JP2010100232A - Suspension member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively inhibit the deformation of a suspension member with a simple constitution. <P>SOLUTION: Since shelf-shaped parts 122, 222 are formed on side wall parts 106, 206 of curving parts 104, 204 of side rails 100, 200 of a suspension member 10, the rigidities (planar-view flexural rigidities) of the side wall parts 106, 206 of the curving parts 104, 204 are improved. Therefore, flexural deformation (planar-view flexural deformation) in the vehicle fore-and-aft direction at the curving parts 104, 204 caused by a fore-and-aft input force from tires 58, 68 can be effectively inhibited. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle suspension member.

  It is known that a pair of left and right side members extending in the vehicle front-rear direction are provided on both outer sides in the vehicle width direction, and a suspension member (subframe) having a substantially well shape in plan view is bridged between the side members. Yes.

The pair of left and right side rails constituting the suspension member (subframe) is a closed cross-sectional structure in which a side rail upper and a side rail lower formed by press molding are overlapped in the vertical direction and spot welded. A suspension member (subframe) has been proposed in which an upright wall and a plurality of reinforcing bulges are provided at the joint between the side rail upper and the side rail lower to increase rigidity and durability.
JP 2007-168754 A

  However, it is desired to effectively suppress the deformation of the suspension member with a simple configuration.

  In consideration of the above, an object of the present invention is to effectively suppress the deformation of the suspension member, particularly the deformation of the curved portion, with a simple configuration.

  The invention according to claim 1 has a closed cross-sectional structure in which the side rail upper and the side rail lower are overlapped and joined in the vehicle vertical direction, and the vehicle rear side portion is curved outward in the vehicle width direction. A pair of side rails arranged at intervals in the vehicle width direction along the direction, and the side rail upper and the side rail at the side wall portion on the vehicle width direction outer side of the curved portion of the vehicle rear side portion of the side rail. And a shelf-shaped portion that is formed along a joint portion with the lower and that is recessed on the outer side and protrudes in a shelf shape on the inner side.

  Accordingly, the rigidity of the curved portion of the side rail is improved, and for example, bending deformation in the vehicle longitudinal direction at the curved portion due to the longitudinal input from the tire is effectively suppressed.

  According to a second aspect of the present invention, in the suspension member according to the first aspect, the shelf-shaped portion is formed in the vicinity of the joint portion in parallel or substantially parallel to the joint portion.

  Therefore, the stress at the joint portion at the curved portion is effectively reduced, and as a result, the peeling deformation at the joint portion at the curved portion is effectively suppressed.

  According to a third aspect of the present invention, in the suspension member according to the first or second aspect, the shelf-shaped portion is formed in at least one of the side rail upper and the side rail lower.

  Accordingly, the rigidity of at least one of the curved portions of the side rail upper and the side rail lower is improved, and for example, bending deformation in the vehicle longitudinal direction at the curved portion due to the longitudinal input from the tire is effectively suppressed.

  According to a fourth aspect of the present invention, in the suspension member according to the third aspect, the side rail upper and the side rail lower are formed by press molding, and at least one of the side rail upper and the side rail lower at the time of press molding. The shelf-shaped portion is formed on the side wall portion of this.

  Therefore, a shelf-shaped portion without a press load (or with a small press load) is easily formed during press molding.

  According to the first aspect of the present invention, it is possible to effectively suppress the deformation of the suspension member, particularly the deformation of the curved portion, with a simple configuration.

  According to the second aspect of the present invention, it is possible to effectively suppress the peeling deformation of the joint portion at the curved portion of the suspension member.

  According to the third aspect of the present invention, it is possible to effectively suppress bending deformation in the vehicle front-rear direction in at least one of the curved portions of the side rail upper and the side rail lower.

  In the invention according to claim 4, the shelf-shaped portion can be easily formed by press molding.

  An example of the embodiment of the suspension member of the present invention will be described in detail with reference to FIGS. In each figure, the arrow UP indicates the vehicle upward direction, the arrow RR indicates the vehicle rear direction, and the arrow OUT indicates the vehicle width direction outer side direction.

  FIG. 1 is a plan view of a suspension member according to an embodiment of the present invention as viewed from above the vehicle. 2A is a bottom view of the suspension member according to the embodiment of the present invention as viewed from the lower side of the vehicle, and FIG. 2B is an enlarged bottom view of the portion B surrounded by the square in FIG. 2A. FIG.

  FIG. 3A is a perspective view of the suspension according to the embodiment of the present invention as viewed obliquely from the lower front side of the vehicle, and FIG. 3B is an enlarged view of a portion B surrounded by a square in FIG. It is a perspective view. FIG. 3C is an enlarged perspective view of a portion corresponding to FIG. 3B in the suspension member to which the present invention is not applied. FIG. 4 is a cross-sectional view taken along line AA in FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3C.

  FIG. 5A is a side view showing a curved portion of the suspension member. 5B is a cross-sectional view taken along the line BB in FIG. 5A in a state where the curved portion is deformed, and FIG. 5C is taken along the line CC in FIG. 5A. It is sectional drawing. 5B and 5C are enlarged cross-sectional views in which a portion surrounded by a square in the left diagram is enlarged. 5B and 5C are cross-sectional views in a state where the curved portion of the suspension member to which the present invention is not applied is deformed.

  As shown in FIGS. 1, 2, and 3 (A), the suspension member 10 includes a rear cross member 20 between a pair of side rails 100, 200 arranged along the vehicle longitudinal direction on both outer sides in the vehicle width direction. And the front cross member 30 are formed in a substantially well shape in plan view. In addition, the suspension member 10 has mounting portions 12, 14, 16, and 18 provided at four corners (both ends of the side rails 100 and 200) at both side ends in the vehicle width direction along the vehicle front-rear direction. Are coupled to a front side member (not shown).

  The pair of side rails 100 and 200 are disposed substantially parallel to the vehicle width direction both sides of the suspension member 10 along the vehicle front-rear direction. The vehicle rear side portions 102 and 202 of these side rails 100 and 200 are curved toward the outer side in the vehicle width direction. Further, the front end portions of the side rails 100 and 200 are bent toward the front side in the vehicle width direction.

  Between the vehicle rear side portions 102 and 202 of the side rails 100 and 200, a rear cross member 20 is installed along the vehicle width direction, and both ends of the rear cross member 20 in the vehicle width direction are respectively side rails. The vehicle rear side portions 102 and 202 (curved portions 104 and 204 thereof) of 100 and 200 are joined to the vehicle width direction inner side portions.

  On the other hand, between the front end portions of the side rails 100 and 200, a front cross member 30 is installed along the vehicle width direction, and both ends of the front cross member 30 in the vehicle width direction are respectively side rails 100 and 200. Are joined to the inner side in the vehicle width direction.

  The pair of side rails 100 and 200 are overlapped by facing (facing) the side rail uppers 110 and 210 and the side rail lowers 120 and 220 made of press-formed (pressed) steel plates, and arc welding. Thus, a closed cross-sectional structure is formed (see also FIGS. 4 and 5A).

  As shown in FIGS. 2, 3 (A), 3 (B), and 4, the side rail upper 110 and the side rail of the side wall portion 106 on the outer side in the vehicle width direction at the curved portion (corner portion) 104 of the side rail 100. A shelf-shaped portion 122 is formed in the vicinity of the vehicle lower side of the joint portion (arc welding portion) 130 with the lower 120 (the shelf-shaped portion 122 is formed in the vicinity of the upper end portion of the side wall portion 121 of the side rail lower 120. ).

  As shown in FIG. 4, the shelf-shaped portion 122 is formed so that the outer side surface is concave and the inner side surface is convex, and the shelf-like portion projects inward in a shelf shape. Further, the shelf-shaped portion 122 has a substantially triangular cross section, a shelf portion 122A that constitutes an upper portion that is slightly inclined obliquely inwardly downward, and an inclination that is inclined obliquely outwardly and downwardly from the end of the shelf portion 122A to constitute a slope. And a surface portion 122B. The inclined surface portion 122B has a draft angle θ with respect to the pressing direction P (see also FIG. 8C, details will be described later).

  3B, the shelf-shaped portion 122 extends from the vehicle rear side end portion of the curved portion 104 to the vehicle front side end portion along the joint portion 130 in parallel or substantially parallel to the joint portion 130. (From the beginning to the end of R).

  Although the shelf-shaped portion 122 formed on the side wall portion 106 of the curved portion 104 of the side rail 100 has been described, the same applies to the shelf-shaped portion 222 formed on the side wall portion 206 of the curved portion 204 of the opposite side rail 200. Since it is the structure of this, description is abbreviate | omitted.

  As shown in FIG. 1, the suspension member 10 supports a pair of left and right suspension arms 50 and 60 constituting a suspension so as to be rotatable (movable) in the vehicle vertical direction. The suspension arms 50, 60 include vehicle front side portions 52, 62 arranged with the vehicle width direction as a longitudinal direction, and a vehicle rear side portion 54 extended from the vehicle front side portion 52 in an oblique rearward direction in the vehicle width direction, 64, and is substantially Y-shaped in plan view.

  Ends on the vehicle width direction inner side of the vehicle front side portions 52 and 62 of the suspension arms 50 and 60 are connected to the vehicle front side slightly in the vehicle longitudinal direction center portion of the side rails 100 and 200, and the vehicle rear side portions 54 and 64 The end portions are connected to the front end side slightly from the curved portions 104 and 204 of the vehicle rear side portions 102 and 202 of the side rails 100 and 200. Tires 58 and 68 are supported at the outer ends of the suspension arms 50 and 60 in the vehicle width direction.

  Next, the operation of this embodiment will be described.

  When starting and braking, front and rear inputs from the tires 58 and 68 cause bending deformation (bending deformation in the vehicle longitudinal direction) in the curved portions 104 and 204 of the side rails 100 and 200. Thereby, peeling deformation may occur in the joint portions 130 and 230 in the curved portions 104 and 204 of the side rails 100 and 200.

  However, in this embodiment, since the shelf-shaped portions 122 and 222 are formed on the side wall portions 106 and 206 of the curved portions 104 and 204, the rigidity (bending rigidity in plan view) of the side wall portions 106 and 206 of the curved portions 104 and 204 is formed. ) Has been improved. Therefore, bending deformation (bending deformation in plan view) in the vehicle front-rear direction in the curved portions 104, 204 due to the front-rear input from the tires 58, 68 is effectively suppressed.

  Further, since the shelf-shaped portions 122 and 222 are formed in the vicinity of the joint portions 130 and 230 of the curved portions 104 and 206 in parallel or substantially parallel to the joint portions 130 and 230, the stress of the joint portions 130 and 230 is effective. As a result, the peeling deformation of the joints 130 and 230 is effectively suppressed.

  Next, suppression of bending deformation (bending deformation in plan view) in the vehicle front-rear direction in the curved portions 104 and 204 due to front and rear inputs from the tires 58 and 68 will be described in detail with reference to FIGS. 3 and 5 to 7. Note that, as a representative, a configuration in which the shelf-shaped portion 122 is not formed for suppressing bending deformation in the vehicle front-rear direction in the curved portion 104 due to front-rear input from the tire 58 during braking (see FIGS. 3C and 4). Reference) and will be described.

  As described above, FIG. 3 (A) is a perspective view of the suspension member according to the embodiment of the present invention as viewed obliquely from the lower front side of the vehicle, and FIG. 3 (B) is a square in FIG. 3 (A). FIG. 3 (C) is an enlarged perspective view of a portion corresponding to FIG. 3 (B) in a suspension member to which the present invention is not applied. FIG. 4 is a cross-sectional view taken along line AA in FIG. In addition, the dashed-two dotted line of FIG. 4 is sectional drawing along the AA line of FIG.3 (C) (structure in which the shelf-shaped part is not formed).

  FIG. 5A is a side view showing a curved portion of the suspension member. 5B is a cross-sectional view taken along the line BB in FIG. 5A in a state where the curved portion is deformed, and FIG. 5C is taken along the line CC in FIG. 5A. It is sectional drawing. 5B and 5C are enlarged cross-sectional views in which a portion surrounded by a square in the left diagram is enlarged. 5B and 5C are cross-sectional views in a state where the curved portion of the suspension member to which the present invention is not applied (the shelf-shaped portion is not formed) is deformed.

  FIG. 6A is an explanatory diagram for explaining the front-rear input from the tire 58 during braking, and is a plan view of the suspension member corresponding to FIG. 1 as viewed from the vehicle upper side. 6 (B) and 6 (B) are enlarged plan views in which the curved portion 104 of (A) is enlarged.

  FIG. 7 (A) shows a stress portion distribution of the main part corresponding to FIG. 3 (C) to which the present invention is not applied (the shelf-shaped portion is not formed), and FIG. 7 (B) is the present invention. 3 is a stress part distribution of a main part corresponding to FIG. 3B to which is applied (a shelf-shaped part is formed). It should be noted that a dot having a higher density is given to a portion where the generated stress is higher.

  As shown in FIG. 6A, a portion M2 supporting the end portion of the vehicle front side portion 52 of the suspension arm 52 in the suspension member 10 by the longitudinal input by the longitudinal force F1 generated in the tire 58 at the time of braking, As indicated by an arrow F2, force is applied (input) in the vehicle width direction outer side direction (longitudinal direction of the vehicle front side portion 52).

  Further, a portion M3 supporting the end portion of the vehicle rear side portion 54 of the suspension arm 50 in the suspension member 10 has an oblique rearward direction in the vehicle width direction (longitudinal direction of the vehicle rear side portion 54) as indicated by an arrow F3. Force is applied (input).

  As a result, as shown in FIG. 6 (B), a bending deformation in a plan view may occur in the curved portion 104 of the suspension member 10 (a bending deformation in a plan view occurs in the bending portion 104 by the front and rear input from the tire 58). Sometimes). In addition, in order to make it easy to understand, the deformation amount of the curved portion 104 is shown larger than the actual amount (exaggerated).

  However, in this embodiment, since the shelf-shaped portion 122 is formed in the curved portion 104, the bending rigidity of the curved portion 104 in plan view is improved. Therefore, the amount of bending deformation is reduced (see the comparison between the solid line and the two-dot broken line in FIG. 5B), and the stress in the vicinity of the joint 130 of the curved portion 104 is reduced (FIGS. 7A and 7). Compare with (B)). As a result, since the deformation amount of the cross-sectional deformation of the curved portion 104 is reduced, the peeling deformation of the joint 130 is reduced (see the comparison between the solid line and the two-dot broken line in FIG. 5C).

  Note that the shelf-shaped portion 122 is formed in the vicinity of the joint portion 130 along the joint portion 130 in parallel or substantially parallel to the joint portion 130 (see FIG. 5A). Therefore, the peeling deformation of the joint portion 130 of the curved portion 104 is effectively reduced. (See FIG. 7A and FIG. 7B for comparison).

  Next, a method for forming the shelf-shaped portions 122 and 222 will be described with reference to FIG. As a representative, the formation of the shelf-shaped portion 122 will be described.

  FIG. 8A is an image diagram schematically showing press molding of the side rail lower 500 in which the shelf-shaped portion 122 is not formed. FIG. 8B is an enlarged view of the side wall portion 502 of the side rail lower 500 in FIG. FIG. 8C is an enlarged view of the side wall 121 of the image diagram schematically showing the side rail lower 120 on which the shelf-shaped portion 122 is formed (note that the actual shelf-shaped portion 122 (see FIG. 4) is the same). The shape is slightly different for clarity.) FIG. 8D is a diagram in which a bead 504 having a substantially rectangular cross section is formed on the side wall portion 502 of the side rail lower 500 so that the inner side surface is concave and the outer side surface is convex.

  As shown in FIGS. 8A and 8B, the side wall 502 is generally provided with a draft angle θ (having an angle of θ with respect to the pressing direction) of the press-molding die K. ing. Further, since the curved portion has a planar shape with low rigidity, it can be formed by such general press molding. The arrow P indicates the pressing direction.

  And as shown in FIG.8 (C), the shelf shape part 122 is formed so that an outer side surface may be dented and an inner side surface may become convex, and it may protrude in a shelf shape inside. In addition, the shelf-shaped portion 122 includes a shelf portion 122A and an inclined surface portion 122B. The inclined surface portion 122B has a draft angle θ with respect to the press direction (has an angle with respect to the press direction). Therefore, since there is no press load, the shelf-shaped portion 122 can be easily formed on the side wall 121 of the side rail lower 120 by press molding. In other words, similarly to FIG. 8A, the side rail lower 120 in which the shelf-shaped portion 122 is formed can be formed by normal press molding.

  In addition, as shown in FIG. 8D, a bead 504 having a substantially rectangular cross section with a concave inner surface and a convex outer surface is formed on the side wall 502 of the side rail lower 500 in the same manner as in FIG. It cannot be formed by press molding. In other words, it is necessary to mold with a special molding method and special equipment, which makes it difficult to produce and high cost.

  As described so far, the deformation of the curved portion 104 of the suspension member 10 can be effectively suppressed by the shelf-shaped portion 122 that can be easily formed.

  In recent years, the tire front and rear force generated at the time of starting and braking (F1 in FIG. 6 (A)) due to the increase in tire size, shortening of the braking rest distance, and increase in engine output (torque) capacity, which are market needs in recent years. Increase). Thereby, since the input to the suspension member also increases, the durability strength of the suspension member relatively decreases. Therefore, in order to maintain the durability of the suspension member against the tendency to increase the input, it is necessary to reinforce the curved portion having a particularly heavy load. However, reinforcing the curved portion increases the weight, and the increase in weight leads to an increase in carbon dioxide emission. In addition, there is a demand for a significant reduction in carbon dioxide emissions from an environmental point of view (reducing carbon dioxide emissions is a challenge for the entire automobile industry). Therefore, there is a need for a suspension member that is lightweight (without increasing weight) and has high durability strength.

  In the present embodiment, as described above, by forming the shelf-shaped portion 122, it is possible to join the curved portions 104 without increasing the weight, in other words, without increasing the discharge amount of carbon dioxide. The rigidity in the vicinity of the portion 130 is improved.

  In addition, this invention is not limited to the said embodiment.

  For example, in the above-described embodiment, the shelf-shaped portions 122 and 222 are in the vicinity of the joint portions 130 and 230 of the curved portions 104 and 204, along the joint portions 130 and 230, and parallel or substantially parallel to the joint portions 130 and 230. Although formed, it is not limited to this. If the bending rigidity in plan view is improved, the shelf-shaped portion may be formed obliquely with respect to the joint portions 130 and 230. Further, if the peeling deformation of the joint portions 130 and 230 is improved, the shelf-shaped portion may be formed away from the joint portions 130 and 230.

  Further, for example, in the above-described embodiment, the shelf-shaped portions 122 and 222 are formed from the vehicle rear side end portion to the vehicle front side end portion (from the start to the end of R) of the curved portion 104, but are not limited thereto. . The shelf-shaped portions 122 and 222 may be formed from the rear side of the curved portion 104 to the front side of the vehicle front side end from the vehicle rear side end portion (if it includes from the start to the end of R). Good). Alternatively, the shelf-shaped portions 122 and 222 are formed in a narrower range than the above-described embodiment (from the vehicle rear side end portion of the curved portion 104 to the vehicle front side end portion to the rear side). It may be. When the shelf-shaped portion is formed in a narrow range, the effect of suppressing the bending deformation in plan view is reduced, but the amount of deformation is reduced compared to a configuration in which the shelf-shaped portion is not formed.

  Further, for example, in the above embodiment, the shelf-shaped portion 122 is formed on the vehicle lower side of the joint portion 130 between the side rail upper 110 and the side rail lower 120, that is, the shelf-shaped portion 122 is formed on the side wall portion 121 of the side rail lower 120. However, the present invention is not limited to this. The shelf-shaped portion 122 may be formed on the vehicle upper side of the joint portion 130, that is, the shelf-shaped portion may be formed on the side wall portion of the side rail upper 110. Furthermore, a shelf-shaped portion may be formed on both the vehicle upper side and the lower side of the joint portion 130, that is, both the side rail lower 120 and the side rail portion of the side rail upper 110.

It is the top view which looked at the suspension member which concerns on embodiment of this invention from the vehicle upper side. (A) is the bottom view which looked at the suspension member which concerns on embodiment of this invention from the vehicle downward side, (B) is the expanded bottom view which expanded the B section enclosed with the square of (A). (A) is the perspective view which looked at the suspension member which concerns on embodiment of this invention from the vehicle lower side diagonally forward, (B) is the expansion perspective view which expanded the B section enclosed with the square of (A), (C) is an enlarged perspective view of a portion corresponding to (B) in a suspension member to which the present invention is not applied. It is sectional drawing along the AA line of FIG.3 (B). (A) is a side view showing a curved portion of the suspension member, (B) a right view is a sectional view taken along line BB of (A) in a state where the curved portion is deformed, and a left view is a right view. The right figure in (C) is a cross-sectional view along the line C-C in the state where the curved portion is deformed, and the left figure is a square in the right figure. It is the figure which expanded the part which enclosed. (A) is explanatory drawing for demonstrating the front-back input from the tire at the time of braking, It is the top view which looked at the suspension member corresponding to FIG. 1 from the vehicle upper side, (B) is (A). It is the enlarged plan view which expanded the curved part. (A) is the stress distribution figure of the principal part corresponding to Drawing 3 (C) where the present invention is not applied (the shelf shape part is not formed), and (B) is the present invention applied. It is the stress part distribution of the principal part corresponding to FIG.3 (C) (the shelf shape part is formed). (A) is an image figure which shows typically the press molding of the side rail lower in which the shelf-shaped part is not formed, FIG.8 (B) is an enlarged view of the side wall of the side rail lower of (A), (C) is an enlarged view of the side rail lower side wall in which the shelf-shaped portion is formed, and (D) is a view in which a bead is formed on the side rail lower side wall with a concave inner surface and a convex outer surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Suspension member 100 Side rail 104 Curved part 106 Side wall part 110 Side rail upper 120 Side rail lower 121 Side wall part 122 Shelf-shaped part 130 Joint part 200 Side rail 204 Curved part 210 Side rail upper 220 Side rail lower 222 Shelf-shaped part 230 Joint Part

Claims (4)

The side rail upper and the side rail lower have a closed cross-sectional structure that is overlapped and joined in the vehicle vertical direction, and the vehicle rear side portion is curved outward in the vehicle width direction, and the vehicle width direction along the vehicle longitudinal direction A pair of side rails that are spaced apart from each other,
It is formed along the joint between the side rail upper and the side rail lower at the side wall portion on the vehicle width direction outer side of the curved portion of the vehicle rear side portion of the side rail, and the outer surface is recessed to form a shelf inside. An overhanging shelf-shaped part,
Suspension member characterized by comprising.   The suspension member according to claim 1, wherein the shelf-shaped portion is formed in the vicinity of the joint portion in parallel or substantially in parallel with the joint portion.   The suspension member according to claim 1 or 2, wherein the shelf-shaped portion is formed in at least one of the side rail upper and the side rail lower. The side rail upper and the side rail lower are formed by press molding,
The suspension member according to claim 3, wherein the shelf-shaped portion is formed on at least one side wall of the side rail upper and the side rail lower during press molding.

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