Subframe

Abstract

The subframe (100) includes a base component (110) and a first component (121). The base component (110) includes a base face portion (111) and two longitudinal wall portions (112) located on both sides of the base face portion (111) in the vehicle length direction, and is a groove-shaped member that opens at the lower side in the vehicle height direction. The first component (121) includes a bottom wall portion (121g), a top wall portion (121t), and a side wall portion (121s). The bottom wall portion (121g) and the top wall portion (121t) are arranged in the same direction as the base face portion (111). The top wall portion (121t) is overlapped and joined to the base face portion (111). The longitudinal wall portion (112) and the bottom wall portion (121g) form a groove shape. The side wall portion (121s) is a wall located between the bottom wall portion (121g) and the top wall portion (121t) and shields the vehicle width direction. A first lower arm support portion (131) is formed by the base surface portion (111) and the bottom wall portion (121g).

Description

Technical Field

[0001] The present invention relates to a sub frame.

[0002] This application claims priority based on Japanese Patent Application No. 2020-146523 filed on September 1, 2020, the contents of which are incorporated herein by reference. Background Art

[0003] Conventionally, there is a subframe that is attached to a chassis (main frame) of a vehicle body and supports a lower arm.

[0004] However, there is room for improvement in the conventional subframe in terms of weight reduction and performance of the lower arm supporting portion.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-114422 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The present invention has been made in view of the above-mentioned problems of the background art, and an object of the present invention is to provide a subframe capable of achieving both weight reduction and the performance of a lower arm support portion.

[0010] Means used to solve problems

[0011] The gist of the present invention is as follows.

[0012] (1) A subframe according to a technical solution of the present invention comprises: a base member and a first member; the base member comprises a base face portion and two longitudinal wall portions located on both sides of the base face portion in the vehicle length direction, the base member being a groove-shaped member opening at the lower side in the vehicle height direction; the first member comprises a bottom wall portion, a top wall portion and a side wall portion; the bottom wall portion and the top wall portion are arranged in the same orientation as the base face portion; the top wall portion overlaps and is joined to the base face portion; the longitudinal wall portion and the bottom wall portion form a groove shape; the side wall portion is a wall located between the bottom wall portion and the top wall portion and shielding the vehicle width direction; a first lower arm support portion is formed by the base face portion and the bottom wall portion.

[0013] (2) In the above (1), it may be that the bracket is provided; the bracket includes a second component and a third component; the second component includes a first vehicle body mounting portion at the top, and the second component is joined to the bottom wall portion, the side wall portion and the base surface portion.

[0014] (3) In the above (2), the second lower arm support portion may be formed by the vertical wall portion and the second member.

[0015] (4) In the above (2) or (3), the top wall portion and the second member may be joined in an overlapping manner.

[0016] (5) In any one of the above (2) to (4), the base surface portion and the second member may be joined in an overlapping manner.

[0017] (6) In any one of the above (1) to (5), the first member may include a second lower arm support wall; and the second lower arm support wall may be adjacent to the side wall portion and joined to the vertical wall portion so as to overlap.

[0018] (7) In any one of the above (1) to (6), the base member may include a second vehicle body mounting portion oriented in the same direction as the base surface portion at an end portion of the base member that is closer to the vehicle width direction than the side wall portion.

[0019] (8) In any one of the above (1) to (7), the top wall portion may be joined to the base surface portion in an overlapping manner.

[0020] (9) In any one of the above (1) to (8), an inward flange may be provided adjacent to the vertical wall portion and facing the base surface portion.

[0021] Effects of the Invention

[0022] According to the present invention, it is possible to provide a subframe capable of achieving both weight reduction and the performance of a lower arm supporting portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a perspective view of a portion of a vehicle body including a subframe viewed from below.

[0024] Figure 2 This is a three-dimensional view of the subframe viewed from above.

[0025] Figure 3 This is a perspective view of the subframe viewed from below.

[0026] Figure 4 is a three-dimensional view of the torque rod support bracket.

[0027] Figure 5 It is an exploded perspective view of the bracket.

[0028] Figure 6 yes Figures 1 to 3 The A-direction view is the front view of the subframe.

[0029] Figure 7It is a plan view of the subframe.

[0030] Figure 8 It is a side view of the subframe.

[0031] Fig. 9 This is a bottom view of the subframe.

[0032] Fig.10 This is the rear view of the subframe.

[0033] Fig.11 yes Figure 6 B view. DETAILED DESCRIPTION

[0034] Conventionally, there is a subframe (also called a suspension member) which is a member attached to the chassis of a vehicle body and supports a lower arm of a suspension.

[0035] In order to ensure desired rigidity, the subframe may be a hollow structure in which a closed space is formed between a pair of steel plate members of substantially the same size, and a cross section perpendicular to the vehicle width direction is a closed cross section.

[0036] However, since the subframe of such a structure is a structure obtained by making a pair of steel plate members (a base member and a closing plate thereunder) of the same size face each other and integrally welded to each other, especially the peripheral edges, there is still room for improvement in terms of balancing weight reduction and the performance of the lower arm support portion.

[0037] Therefore, the structure of the subframe was reviewed, and a subframe that can achieve both weight reduction and the performance of the lower arm support portion was found.

[0038] The subframe of the present invention comprises a base member and a first member. The base member is a groove-shaped member that is open at the lower side in the vehicle height direction, and comprises a base face portion and two longitudinal wall portions on both sides of the base face portion in the vehicle length direction. The first member comprises a bottom wall portion, a top wall portion, and a side wall portion. The bottom wall portion and the top wall portion are arranged in the same orientation as the base face portion. The top wall portion is joined to the base face portion in an overlapping manner. The longitudinal wall portion and the bottom wall portion form a groove shape. The side wall portion is a wall that is located between the bottom wall portion and the top wall portion and blocks the vehicle width direction. The first lower arm support portion is formed by the base face portion and the bottom wall portion. Thus, since there is no cover plate across the entire width in the vehicle width direction, the subframe can be made lightweight. In addition, since the side wall portion is adjacent to the lower arm support portion (the first lower arm support portion), the side wall portion is fixed to the base member via the top wall portion, so that the lower arm support portion (the first lower arm support portion) becomes less likely to deform. Furthermore, since the side wall restrains the base member and the bottom wall, the end portion of the subframe in the vehicle width direction is less likely to deform. Therefore, both the weight reduction of the subframe and the performance of the lower arm support portion (first lower arm support portion) can be achieved.

[0039] Hereinafter, embodiments of the present invention will be described.

[0040] (Implementation Method)

[0041] A subframe 100 according to the embodiment will be described.

[0042] Figure 1 This is a perspective view of a portion of the vehicle body 1 including the subframe 100 as viewed from below. Figure 2 This is a perspective view of the subframe 100 viewed from above. Figure 3 This is a perspective view of the subframe 100 viewed from below. Figure 4 1 is a perspective view of the torque rod support bracket 140 . Figure 5 It is an exploded perspective view of the bracket 120 . Figure 6 yes Figures 1 to 3 The view in the direction of A in FIG. 1 is a front view of the subframe 100 . Figure 7 1 is a plan view of the subframe 100 . Figure 8 It is a side view of the subframe 100 . Fig. 9 1 is a bottom view of the subframe 100 . Fig.10 It is a rear view of the subframe 100 . Fig.11 yes Figure 6 B view in the figure.

[0043] Hereinafter, the vehicle length direction of the vehicle body 1 may be referred to as an X direction, the vehicle width direction of the vehicle body 1 may be referred to as a Y direction, and the vehicle height direction of the vehicle body 1 may be referred to as a Z direction.

[0044] (Subframe)

[0045] The subframe 100 will be described.

[0046] The subframe 100 is a component mounted on the vehicle body 1 including the chassis. Figures 1 to 3 and Figures 6 to 11 As shown, when the subframe 100 is mounted on the vehicle body 1, it has a flat shape shorter in the Z direction than in the X direction when viewed in the vehicle width direction (Y direction), and has an elongated shape longer in the Y direction than in the X direction when viewed in the vertical direction (Z direction).

[0047] The subframe 100 may have a shape that is substantially line-symmetrical in the vehicle width direction (centered on the axis of symmetry along the X direction).

[0048] The subframe 100 is a member that supports the lower arm 210. The subframe 100 supports the lower arm 210 including the left lower arm 210L and the right lower arm 210R through the first lower arm support portion 131 (and / or the second lower arm support portion 132). The subframe 100 supports the left lower arm 210L through the left lower arm support portions 131L and 132L, and supports the right lower arm 210R through the right lower arm support portions 131R and 132R. The subframe 100 supports the lower arm 210 so as to be rotatable with a predetermined degree of freedom via a bearing (not shown). In addition, the lower arm 210 is a member that constitutes a suspension 200 that is a device that suspends a vehicle body on wheels.

[0049] The subframe 100 includes a base member 110 extending in the vehicle width direction of the vehicle body 1 and having an open cross section, and a bracket 120 joined to the base member 110 .

[0050] The bracket 120 includes a left bracket 120L that supports the left lower arm 210L and a right bracket 120R that supports the right lower arm 210R.

[0051] Here, the subframe 100 includes a base member 110 and a first member 121 .

[0052] like Figure 2 and Figure 3 As shown, the base member 110 includes a base surface portion 111 and two vertical wall portions 112 (a second vertical wall portion 112f and a first vertical wall portion 112r) located on both sides in the vehicle length direction of the base surface portion 111. The base member 110 is a channel-shaped member that opens downward in the vehicle height direction.

[0053] like Figure 5 As shown in FIG. 1 , the first member 121 includes a bottom wall portion 121 g , a top wall portion 121 t , and a side wall portion 121 s . The bottom wall portion 121 g and the top wall portion 121 t are arranged in the same direction as the base surface portion 111 .

[0054] When viewed in the vehicle length direction, the top wall portion 121t and the bottom wall portion 121g of the first member 121 are arranged on the vehicle width direction outer side relative to the side wall portion 121s to face each other.

[0055] The top wall 121t is joined to the base surface 111 in an overlapping manner. The vertical wall 112 and the bottom wall 121g form a groove shape. The side wall 121s is a wall that blocks the vehicle width direction between the bottom wall 121g and the top wall 121t. The first lower arm support 131 is formed by the base surface 111 and the bottom wall 121g.

[0056] Thus, since there is no closing plate across the entire width in the vehicle width direction, the weight of the subframe 100 can be reduced. In addition, since the side wall portion 121s is provided adjacent to the first lower arm support portion 131 and the side wall portion 121s is fixed to the base member 110 via the top wall portion 121t, the first lower arm support portion 131 becomes less likely to deform. In addition, since the side wall portion 121s constrains the base member 110 and the bottom wall portion 121g, the end portion of the subframe 100 in the vehicle width direction becomes less likely to deform. Therefore, it is possible to achieve both weight reduction of the subframe 100 and performance of the lower arm support portion (first lower arm support portion 131).

[0057] In addition, the left bracket 120L and the right bracket 120R are separated from each other. As a result, the area where the base component 110 and the bracket 120 are joined can be concentrated in two areas, namely, the area where the base component 110 and the left bracket 120L are joined and the area where the base component 110 and the right bracket 120R are joined. Furthermore, in an area where the bracket 120 does not exist at a position opposite to the base component 110, that is, in a space formed between the left bracket 120L and the right bracket 120R, an object that is integrated by welding with respect to the base component 110 can be removed. That is, the area (welding amount) where the base component 110 and the left bracket 120L and the right bracket 120R are joined by mutual welding can be reduced. As a result, the weight and manufacturing cost related to welding can be reduced. Furthermore, since the joints between the base member 110 and the left and right brackets 120L and 120R can be welded to each other, the seat surfaces required for spot welding can be ensured, and therefore the joints can be welded by spot welding instead of arc welding.

[0058] The subframe 100 has a second vehicle body mounting portion 110b or a first vehicle body mounting portion 120b on the base member 110 and the bracket 120, respectively. The subframe 100 is mounted on the vehicle body 1 via the second vehicle body mounting portion 110b or the first vehicle body mounting portion 120b. In the present embodiment, the subframe 100 is mounted on the vehicle body 1 at a total of four locations, namely, two locations of the second vehicle body mounting portion 110b of the base member 110 and two locations of the first vehicle body mounting portion 120b of the bracket 120.

[0059] The base member 110 includes a second vehicle body mounting portion 110 b oriented in the same direction as the base surface portion 111 at an end portion of the base member 110 in the vehicle width direction relative to the side wall portion 121 s .

[0060] In this way, the vehicle width direction end portion of the base member 110 becomes less likely to be deformed by the side wall portion 121 s of the first member 121 , so that the rigidity of the second vehicle body mounting portion 110 b provided at the vehicle width direction end portion can be improved.

[0061] The base member 110 and the bracket 120 have an overlapping connection portion V that are joined to each other in a partially overlapping state. The joining at the overlapping connection portion V is preferably performed by both welding and fastening by bolts or the like, but may be performed by either one. Thus, the rigidity and strength of the overlapping connection portion V can be particularly improved. In addition, by joining the base member 110 and the bracket 120 only at the overlapping connection portion V in the subframe 100, the rigidity and strength of the subframe 100 can be ensured. Thus, the amount of welding can be suppressed. Thus, the weight and manufacturing cost related to welding can be reduced.

[0062] Furthermore, since a seat surface required for spot welding can be secured at the overlapped connection portion V, joining can be performed by spot welding instead of arc welding. This can further reduce the weight and manufacturing cost associated with welding.

[0063] The overlap connection portion V is preferably located at a position where the distance to the first lower arm support portion 131 (or the second lower arm support portion 132), the second vehicle body mounting portion 110b, or the first vehicle body mounting portion 120b is shorter than the distance to the center (centroid in a plan view) of the subframe 100. Thus, the overlap connection portion V can be located near the first lower arm support portion 131 (or the second lower arm support portion 132), the second vehicle body mounting portion 110b, or the first vehicle body mounting portion 120b, which are required to have high rigidity and strength.

[0064] (Base parts)

[0065] The base member 110 is as follows Figures 1 to 3 and Figures 6 to 11 As shown, when viewed in the vehicle width direction (Y direction), the base member 110 is a flat shape shorter in the Z direction than in the X direction, and when viewed in the vertical direction (Z direction), the base member 110 is a shape that is line-symmetrical in the vehicle width direction (centered on the symmetry axis along the X direction).

[0066] The base member 110 is formed by performing plastic working such as press forming on a plate material having substantially uniform plate thickness. The base member 110 is made of steel having a tensile strength of 590 MPa or more, for example. The tensile strength of the base member 110 is preferably 980 MPa or more.

[0067] The base member 110 is formed by plastic working such as press forming, using a substantially homogeneous plate material having a predetermined plate thickness (eg, 2.9 mm) as a base.

[0068] The base member 110 includes a base face portion 111 having an opposing surface facing the vehicle body 1 and a vertical wall portion 112 extending downward from the periphery of the base face portion 111. The base member 110 has a substantially U-shaped cross section (see FIG. 1 ). Fig.11). Thus, the base member 110 having high rigidity can be formed from a single plate material.

[0069] The base member 110 is joined to the left bracket 120L and the right bracket 120R in a state of being overlapped on both a part of the left bracket 120L and a part of the right bracket 120R from above and being bridged between the left bracket 120L and the right bracket 120R.

[0070] The base surface portion 111 extends in a planar shape along a horizontal plane (XY plane). The vertical wall portion 112 extends downward (in the Z direction) from the front end portion of the base surface portion 111 .

[0071] The base surface portion 111 may include a recessed portion 111 k that is appropriately recessed upward or downward. This can improve the rigidity of the base surface portion 111 .

[0072] The base member 110 may include a torque rod support portion 150 for supporting a torque rod (not shown). Specifically, the base member 110 may include a torque rod support portion 150 for supporting a torque rod at a front portion substantially in the center of the base surface portion 111. The torque rod support portion 150 may be a hole provided at a front portion substantially in the center of the base surface portion 111. The torque rod support portion 150 provided on the base surface portion 111 cooperates with the torque rod support portion 150 provided on the torque rod support bracket 140 via a suitable bearing (not shown) to support the torque rod.

[0073] The base member 110 may appropriately include a stabilizer mounting portion 115 including a hole for mounting a stabilizer (not shown).

[0074] The base member 110 may appropriately include a steering rack housing mounting portion 116 including a hole for mounting a steering rack housing (not shown).

[0075] The vertical wall portion 112 includes a first lower arm support portion 131 and a second lower arm support portion 132 at the rear and front of the left and right ends, respectively. Thus, the lower arm 210 can be supported in cooperation with the first lower arm support portion 131 and the second lower arm support portion 132 provided on the bracket 120 .

[0076] The longitudinal wall portion 112 has a second vehicle body mounting portion 110b at the left and right ends of the rear longitudinal wall portion 112 (first longitudinal wall portion 112r). The second vehicle body mounting portion 110b is provided at the left and right ends of the rear longitudinal wall portion 112 (first longitudinal wall portion 112r) so as to extend from the lower end toward the rear (X direction). The second vehicle body mounting portion 110b may be provided integrally on the longitudinal wall portion 112, or may be provided by joining other components to the longitudinal wall portion 112. The second vehicle body mounting portion 110b may also be formed integrally with the rear longitudinal wall portion 112 when the base member 110 is subjected to plastic working such as stamping.

[0077] The vertical wall portion 112 may have an opening portion 112p through which a torque rod constituting the engine mount passes, appropriately at the center of the front vertical wall portion 112 (second vertical wall portion 112f).

[0078] The subframe 100 may also include an inward flange 113, which is adjacent to the vertical wall portion 112 and faces the base surface portion 111. As a result, the secondary wheelbase of the cross section of the subframe 100 is increased, and deformation of the subframe 100 such as bending with the vehicle length direction as the axis can be suppressed. As a result, deformation of the lower arm 210 in the vehicle width direction can be suppressed.

[0079] In detail, the vertical wall portion 112 may have an inward flange 113 extending from the lower end of the vertical wall portion 112 in the vehicle length direction (X direction) of the vehicle body 1. Specifically, the base member 110 may have an inward flange 113 extending from the lower end of the vertical wall portion 112 on the front side toward the rear (X direction). Similarly, the base member 110 may also have an inward flange 113 extending from the lower end of the vertical wall portion 112 on the rear side toward the front (X direction).

[0080] The inward flange 113 extends from the lower end of the vertical wall portion 112 toward the X direction by a length of, for example, about 10 mm. The inward flange 113 is provided at the lower end of the vertical wall portion 112 from the left end to the right end of the vertical wall portion 112 along the Y direction. Thus, the bending rigidity and torsional rigidity of the subframe 100 can be mainly improved.

[0081] The subframe 100 may include a torque rod support bracket 140, which is provided so as to span from the first vertical wall portion 112r to the second vertical wall portion 112f and form a hollow portion between the base member 110. The torque rod support bracket 140 includes a torque rod support portion 150 that supports the torque rod in cooperation with the torque rod support portion 150 of the base surface portion 111. Thus, the rigidity of the torque rod support portion 150 can be increased, and the overall rigidity of the subframe 100 can be increased.

[0082] The base member 110 is formed to be bent in the transition portion from the base face portion 111 to the longitudinal wall portion 112 and the transition portion from the longitudinal wall portion 112 to the inward flange 113. In addition, a space is formed between the first longitudinal wall portion 112r and the second longitudinal wall portion 112f that are separated from each other. In addition, a space is formed between the rear end of the front inward flange 113 and the front end of the rear inward flange that are separated from each other. In this way, since the base member 110 has an open cross-section formed by the base face portion 111, the longitudinal wall portion 112, and the appropriate inward flange 113, rigidity can be ensured, and it can be formed from a single sheet of blank material by plastic processing such as stamping without requiring joining means such as spot welding and arc welding.

[0083] (bracket)

[0084] The bracket 120 is formed by performing plastic working such as press forming on a plate blank material having substantially uniform plate thickness. The bracket 120 includes a left bracket 120L and a right bracket 120R. The left bracket 120L is joined to the left end of the base member 110 by an appropriate joining means such as spot welding. The right bracket 120R is joined to the right end of the base member 110 by an appropriate joining means such as spot welding. The left bracket 120L and the right bracket 120R are line-symmetrical in the vehicle width direction (centered on the symmetry axis along the Z direction).

[0085] In the following, regarding the bracket 120 , there is a case where the left bracket 120L is used as a representative example for explanation.

[0086] like Figure 5 As shown, the left bracket 120L (bracket 120 ) includes a second member 122 and a third member 123 .

[0087] Here, the second member 122 has the first vehicle body mounting portion 120 b at the top thereof. The second member 122 is joined to the bottom wall portion 121 g of the first member 121 , the side wall portion 121 s of the first member 121 , and the base surface portion 111 of the base member 110 .

[0088] Thus, the side wall portion 121s which has high rigidity and is not easily deformed and forms the end portion in the vehicle width direction of the subframe 100 can contribute to the rigidity of the first vehicle body mounting portion 120b. In addition, by joining the second member 122 to the side wall portion 121s of the first member 121, the side wall portion 121s which has high rigidity and is not easily deformed and forms the end portion in the vehicle width direction of the subframe 100 can contribute to the rigidity of the first vehicle body mounting portion 120b.

[0089] The second lower arm support portion 132 may be formed by the vertical wall portion 112 and the second member 122 .

[0090] Thus, the vertical wall portion 112 having high rigidity and the side wall portion 121 s of the first member 121 joined to the second member 122 can contribute to the rigidity of the second lower arm support portion 132 .

[0091] The first member 121 includes a second lower arm support wall 121a. The second lower arm support wall 121a may be adjacent to the side wall portion 121s and joined to the vertical wall portion 112 (second vertical wall portion 112f) so as to overlap.

[0092] Thus, since the side wall portion 121s constrains the second lower arm support wall 121a, the rigidity of the second lower arm support portion 132 can be improved.

[0093] The top wall portion 121 t may be joined to the base surface portion 111 in an overlapping manner.

[0094] Thus, the side wall portion 121s can be made less likely to deform than by performing fillet welding by abutting the side wall portion 121s against the base surface portion 111. In addition, in terms of rust prevention and implementation cost, the joining in which the surfaces overlap each other is more advantageous than fillet welding. In addition, the joining in which the surfaces overlap each other does not require the surfaces to be joined as a whole, but can be point joining. Examples of point joining include welding such as spot welding and laser welding, and fastening such as threaded fixing and rivet fixing.

[0095] like Figure 5 As shown, the top wall portion 121t and the second member 122 may be joined in an overlapping manner.

[0096] Thus, deformation of the second member 122 can be suppressed.

[0097] like Figure 2 As shown, the base surface portion 111 and the second member 122 may be joined in an overlapping manner.

[0098] Thus, deformation of the second member 122 can be suppressed.

[0099] In addition, if Figure 5 As shown, the left side bracket 120L (bracket 120) includes: a first component 121, which has an open cross-section and includes left lower arm support portions 131L, 132L (the first lower arm support portion 131 and the second lower arm support portion 132); a second component 122, which is joined to the first component 121, has an open cross-section and includes the left lower arm support portion 131L and the first vehicle body mounting portion 120b; and a third component 123, which is joined to the second component 122, has an open cross-section and includes a lower arm support portion.

[0100] Thus, even if the bracket 120 has a complicated structure, it can be manufactured by joining a plurality of parts formed by plastic working such as press forming of a plate blank having substantially uniform plate thickness in an overlapping state. Furthermore, since the plates can be overlapped in the portion of the bracket 120 that requires rigidity (for example, the left lower arm support portions 131L, 132L, the first vehicle body mounting portion 120b), the rigidity and strength of the required portion can be improved.

[0101] The first component 121, the second component 122, and the third component 123 are formed by performing plastic working such as press forming on a plate blank having substantially uniform plate thickness. The first component 121, the second component 122, and the third component 123 are joined to each other by appropriate joining means such as spot welding (in Figure 5 The parts are joined together (the parts indicated by the circular dotted lines in FIG. 1 ).

[0102] The first member 121 has a bottom wall portion 121g whose upper surface is exposed and faces the vehicle body 1, and a side wall portion 121s extending upward from the bottom wall portion 121g toward the base member 110. Thus, the upper surface of the bottom wall portion 121g faces the vehicle body 1 and is exposed, and a cross section perpendicular to the vehicle width direction (Y direction) in the subframe 100 can be made into an open cross section. Thus, the subframe 100 can be made lightweight. In addition, the first member 121 can be formed from a single sheet of plate material by plastic working such as press forming.

[0103] In addition, the upper surface of the bottom wall portion 121g is preferably separated from the lower surface of the base surface portion 111 of the base member 110 (see Figure 8 ) Since the upper surface of the bottom wall portion 121g is separated from the lower surface of the base surface portion 111 of the base member 110, the rigidity can be improved especially with respect to bending centered in the Z direction and the Y direction.

[0104] Furthermore, since the first member 121 has the side wall portion 121s formed by bending from the end of the bottom wall portion 121g, the rigidity can be improved particularly with respect to bending centered in the Z direction. Since the first member 121 has the side wall portion 121s, the load generated between the first vehicle body mounting portion 120b and the first lower arm support portion 131 and the second lower arm support portion 132 in the plate surface direction can be received and effectively resisted. Thus, the subframe 100 can ensure the required rigidity and strength, and can also be made lightweight.

[0105] The second member 122 includes a second lower arm support portion 132 and a first vehicle body mounting portion 120b. The second member 122 is joined to the first member 121 by a joining means s such as spot welding in a state where a portion of the second member 122 overlaps the first member 121. The second lower arm support portion 132 provided on the second member 122 supports the lower arm 210 in cooperation with the second lower arm support portion 132 provided on the first member 121.

[0106] The third component 123 is joined by a joining means s such as spot welding in a state where a part of the third component 123 overlaps with the second component 122. The third component 123 may have a second lower arm support portion 132. The second lower arm support portion 132 of the third component 123 overlaps with the second lower arm support portion 132 of the second component 122. Thus, the rigidity and strength of the second lower arm support portion 132 can be improved. In addition, the third component 123 is joined to the second component 122 in a manner that a closed space is formed between the third component 123 and the second component 122. The cross section perpendicular to the Z direction formed by the second component 122 and the third component 123 is a closed cross section. Thus, the rigidity and strength of the vicinity of the first vehicle body mounting portion 120b can be improved.

[0107] (Torque rod support bracket)

[0108] The torque rod support bracket 140 is formed by performing plastic working such as press forming on a plate material having substantially uniform plate thickness. Figure 4 As shown, the torque rod support bracket 140 includes a bridge portion 145 extending from one end portion 141 toward the other end portion 142 along the X direction, and a connecting portion 146 that is integral with the bridge portion 145 and extends toward the left and right along the Y direction. The torque rod support bracket 140 is generally T-shaped. The torque rod support bracket 140 is an open cross-section as a whole. One end portion 141 of the torque rod support bracket 140 is joined to the first longitudinal wall portion 112r or the inward flange 113 of the base member 110 by a joining means s such as spot welding. In addition, the connecting portion 146 at the other end portion 142 of the torque rod support bracket 140 is joined to the second longitudinal wall portion 112f or the inward flange 113 of the base member 110 by a joining means s such as spot welding. The torque rod support bracket 140 has a torque rod support portion 150.

[0109] (Method of manufacturing subframe)

[0110] Next, a method for manufacturing the subframe 100 will be described.

[0111] (1) First, the base member 110 is manufactured.

[0112] Specifically, a substantially homogeneous plate material having a predetermined plate thickness (eg, 2.9 mm) is prepared, and then a base member 110 is formed by press forming, wherein the base member 110 has a base surface portion 111, a vertical wall portion 112, and an appropriate inward flange 113 and has a substantially U-shaped cross section.

[0113] (2) Manufacturing the bracket 120 (bracket manufacturing step). Specifically, a substantially homogeneous plate blank having a predetermined plate thickness (for example, 3.6 mm) is formed by press forming. Figure 5 The first component 121, the second component 122 and the third component 123 constituting the bracket 120 are formed as shown. Then, they are overlapped and joined by spot welding. Then, the left bracket 120L and the right bracket 120R formed in this way and having a line-symmetrical relationship with each other are prepared.

[0114] (3) Next, the base member 110 and the bracket 120 are welded by spot welding and fastening members such as bolts. Specifically, the base member 110 is arranged so as to be bridged between the left bracket 120L and the right bracket 120R. Next, the overlapping portions of the base member, the left bracket 120L, and the right bracket 120R are fastened by fastening members and joined by spot welding.

[0115] In this way, the subframe 100 can be manufactured. Thus, the subframe 100 capable of reducing the manufacturing cost related to welding can be provided.

[0116] <Other Embodiments>

[0117] As mentioned above, although one embodiment was described in detail with reference to drawings, the specific structure is not limited to the above, and various design changes and the like can be made.

[0118] The subframe 100 according to the present embodiment includes a base member 110 and a first member 121. The base member 110 includes a base face portion 111 and two longitudinal wall portions 112 located on both sides of the base face portion 111 in the vehicle length direction. The base member 110 is a channel-shaped member that is open on the lower side in the vehicle height direction. The first member 121 includes a bottom wall portion 121g, a top wall portion 121t, and a side wall portion 121s. The bottom wall portion 121g and the top wall portion 121t are arranged in the same direction as the base face portion 111. The top wall portion 121t is joined to the base face portion 111 in an overlapping manner. The longitudinal wall portion 112 and the bottom wall portion 121g form a channel shape. The side wall portion 121s is a wall located between the bottom wall portion 121g and the top wall portion 121t and shields the vehicle width direction. The first lower arm support portion 131 is formed by the base face portion 111 and the bottom wall portion 121g. Thus, since there is no cover plate across the entire width in the vehicle width direction, the weight of the subframe 100 can be reduced. In addition, since the side wall portion 121s is adjacent to the first lower arm support portion 131 and the side wall portion 121s is fixed to the base member 110 via the top wall portion 121t, the first lower arm support portion 131 is less likely to be deformed. In addition, since the side wall portion 121s constrains the base member 110 and the bottom wall portion 121g, the end portion of the subframe 100 in the vehicle width direction is less likely to be deformed. Therefore, the weight reduction of the subframe 100 and the performance of the first lower arm support portion 131 can be achieved at the same time.

[0119] Description of symbols

[0120] 1 vehicle body; 100 subframe; 110 base member; 110b second vehicle body mounting portion; 111 base face portion; 111k recessed portion; 112 longitudinal wall portion; 112f second longitudinal wall portion; 112p opening portion; 112r first longitudinal wall portion; 113 inward flange; 115 stabilizer mounting portion; 116 steering rack housing mounting portion; 120 bracket; 120b first vehicle body mounting portion; 120L left side bracket; 120R right side bracket; 121 first member; 121a second lower arm support wall; 121g bottom wall portion; 121s side wall portion; 12 1t top wall portion; 122 second component; 123 third component; 131 first lower arm support portion; 131L left lower arm support portion; 131R right lower arm support portion; 132 second lower arm support portion; 132L left lower arm support portion; 132R right lower arm support portion; 140 torque rod support bracket; 141 one end portion; 142 other end portion; 145 bridging portion; 146 connecting portion; 150 torque rod support portion; 200 suspension (suspension); 210 lower arm; 210L left lower arm; 210R right lower arm; s joining means; V overlapping connecting portion.

Claims

1. A subframe, characterized in that: A base member and a first member are provided. The base member includes a base face portion and two longitudinal wall portions located on both sides of the base face portion in the vehicle length direction. The base member is a groove-shaped member that opens at the lower side in the vehicle height direction. The first component comprises a bottom wall portion, a top wall portion and a side wall portion, The bottom wall portion and the top wall portion are arranged in the same direction as the base surface portion. The top wall portion is joined to the base surface portion in an overlapping manner. The two vertical wall portions and the bottom wall portion form a groove shape. The side wall portion is a wall located between the bottom wall portion and the top wall portion and shielding the vehicle width direction. The base surface and the bottom wall form a first lower arm support portion. The subframe has no cover plate across the entire width of the vehicle width direction.

2. The subframe according to claim 1, characterized in that: With bracket, The bracket comprises a second component and a third component. The second member includes a first vehicle body mounting portion at a top portion, and the second member is joined to the bottom wall portion, the side wall portion, and the base surface portion.

3. The subframe according to claim 2, characterized in that: A second lower arm support portion is formed by the vertical wall portion located on the front side in the vehicle length direction and the second member.

4. The subframe according to claim 2 or 3, characterized in that: The top wall portion and the second member are joined to each other in an overlapping manner.

5. The subframe according to claim 2 or 3, characterized in that: The base surface portion and the second member are joined to each other in an overlapping manner.

6. The subframe according to any one of claims 1 to 3, characterized in that: The first component includes a second lower arm supporting wall, The second lower arm support wall is adjacent to the side wall portion and is joined to overlap with the vertical wall portion located on the front side in the vehicle length direction.

7. The subframe according to any one of claims 1 to 3, characterized in that: The base member includes a second vehicle body mounting portion oriented in the same direction as the base surface portion at an end portion of the base member that is closer to the vehicle width direction than the side wall portion.

8. The subframe according to any one of claims 1 to 3, characterized in that: The top wall portion is joined to the base surface portion so as to overlap.

9. The subframe according to any one of claims 1 to 3, characterized in that: An inward flange is provided, the inward flange being adjacent to the vertical wall portion and facing the base surface portion.

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