JP2022112090A - Vehicle lower part structure - Google Patents

Abstract

To provide a vehicle lower part structure that is able to improve the NV characteristics and steering stability of a vehicle by suppressing torsional vibration of a floor panel.SOLUTION: A vehicle lower part structure 100 according to the present invention includes: side sills 104, 106 extending in a vehicle lengthways direction along edges 112, 114 of a floor panel 102 forming a floor surface of a vehicle; rear side members 108, 110 extending from a rear end 116 of the vehicle toward a vehicle front and connected to rear end portions 118, 120 of the side sills; suspension fixing portions 122, 124 connected to the rear side members to fix swinging suspensions for rear wheels; and a coupling member 128 having X-coupled portions 150 extending obliquely rearward from the respective side sills, crossing each other, and coupled to the respective rear side members. Each of the X-coupled portions of the coupling member and each of the suspension fixing portions are adjacent to each other on each rear side member or face each other with the rear side member therebetween.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle undercarriage.

A vehicle such as an automobile includes a vehicle lower structure including a suspension fixing portion to which a swinging suspension for a rear wheel is fixed, and a rear side member extending forward from the rear end of the vehicle and connected to the suspension fixing portion.

In such a vehicle lower structure, a load in the swing axis direction of the suspension is applied from the suspension fixing portion to the rear side member due to lateral acceleration (lateral G) when the vehicle is turning, for example, while the vehicle is running. The rear side member vibrates in the swing axis direction. When the rear side member vibrates in the swing axis direction, the vibration causes torsional vibration of the vehicle body and floor vibration of the floor panel.

Further, in the vehicle lower structure, one of the front, rear, left, and right wheels may receive a vertical load, such as the inertial force of the vehicle acting on the outer wheel side when the vehicle turns. In such a case, torsional vibration occurs with the maximum amplitude at the lower surface of the wheel-side floor panel located diagonally to the wheel receiving the load. This torsional vibration includes a vibration component in the vertical direction and a vibration component in the vehicle width direction. In the vehicle lower structure, these vibrations cause the lower surface of the floor to vibrate, and this vibration makes it difficult to improve NV (Noise and Vibration) characteristics and steering stability of the vehicle.

Patent Literature 1 describes a suspension support structure for an automobile. In this support structure, a bending member 13 bending toward the side sill 2 and a torque box 43 are provided at the front end of the rear frame 12 . The torque box 43 is arranged behind the bending member 13 and connects the rear frame 12 and the side sill 2 . Furthermore, in this support portion structure, these members have a closed cross-sectional structure, and a trailing arm 7 constituting a rear suspension is fixed to the bottom surface thereof by a support bracket 6 . Thus, in this structure, the support rigidity of the support bracket 6 in the longitudinal direction of the vehicle body is increased.

Japanese Patent No. 4349039

In the support portion structure of Patent Document 1, due to lateral acceleration (lateral G) when the vehicle turns, the swing axis of the rear suspension moves from the trailing arm 7 via the support bracket 6, the bending member 13 and the torque box 43. Directional vibration is transmitted to the rear frame 12 . In such a support structure, this vibration may cause torsional vibration of the vehicle body or floor vibration of the floor panel.

Further, in the support portion structure of Patent Document 1, when vibration having a vibration component in the vehicle width direction is generated in the rear frame 12, no special measures are taken to efficiently disperse the vibration. Therefore, it is difficult to say that the support structure of Patent Document 1 maintains good NV characteristics and steering stability of the vehicle.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle lower structure capable of suppressing torsional vibration of a floor panel and improving NV characteristics and steering stability of the vehicle.

In order to solve the above-described problems, a typical configuration of a vehicle underbody structure according to the present invention is a vehicle underbody structure that includes a floor panel that forms a floor surface of a vehicle, and the vehicle underbody structure further includes a floor panel along an edge of the floor panel. a pair of side sills extending in the front-rear direction of the vehicle, a pair of rear side members extending forward from the rear end of the vehicle and connected to the rear ends of the pair of side sills, and a rocker for the rear wheels connected to the pair of rear side members. A connecting member comprising a pair of suspension fixing portions to which a moving suspension is fixed, and a connecting member having an X connecting portion extending obliquely rearward from each of the pair of side sills, intersecting each other and further connected to each of the pair of rear side members. The X connecting portion and the pair of suspension fixing portions are adjacent to each other on the pair of rear side members, or face each other across the pair of rear side members.

ADVANTAGE OF THE INVENTION According to this invention, the vehicle lower part structure which can suppress the torsional vibration of a floor panel and can improve the NV characteristic and steering stability of a vehicle can be provided.

1 is a bottom view showing a vehicle lower structure according to an embodiment of the present invention; FIG. FIG. 2 is a view showing part of the vehicle lower structure of FIG. 1; FIG. 2 is a view showing another portion of the vehicle lower structure of FIG. 1; FIG. 2 is a top view showing part of the vehicle lower structure of FIG. 1; It is a figure which shows typically the modification of the vehicle lower part structure of FIG. It is a figure which shows the other modification of the vehicle lower part structure of Fig.2 (a). FIG. 2 is a diagram showing still another modification of the vehicle lower structure of FIG. 1;

A representative configuration of a vehicle underbody structure according to an embodiment of the present invention is a vehicle underbody structure that includes a floor panel that forms a floor surface of the vehicle. a pair of side sills extending in the direction of the vehicle, a pair of rear side members extending forward of the vehicle from the rear end of the vehicle and connected to the rear ends of the pair of side sills, and a swinging suspension for the rear wheels connected to the pair of rear side members. and a connecting member having an X connecting part extending obliquely rearward from each of the pair of side sills, intersecting each other and further connected to each of the pair of rear side members, wherein the X connecting of the connecting member The part and the pair of suspension fixing parts are characterized in that they are adjacent to each other on the pair of rear side members, or face each other across the pair of rear side members.

In the above configuration, the suspension fixing portion is connected to the rear side member. For this reason, the rear side member receives a load in the swing axis direction of the suspension from the suspension through the suspension fixing portion, for example, while the vehicle is running. Therefore, in the above configuration, the X connecting portion of the connecting member and the suspension fixing portion are arranged adjacent to each other on the rear side member or facing each other across the rear side member. The X connecting portion of the connecting member connects the pair of side sills and the pair of rear side members along, for example, a diagonal line so as to intersect, thereby increasing the torsional rigidity of the floor panel.

In the above configuration, the load transmitted from the suspension fixed portion to the rear side member on either the left or right side can be dispersed and released to the side sill on the opposite side via the X connecting portion of the connecting member. In addition, the load transmitted from the front member located in the lower front part of the floor panel to the left or right side sill, especially the vibration in the vehicle width direction, is transferred to the opposite rear side through the X connection part of the connection member. Even the members can be dispersed and escaped. Therefore, according to the above configuration, by suppressing the torsional vibration of the floor panel and reducing the torsional vibration of the vehicle body and the floor vibration of the floor panel caused by the vibration of the rear side member, the NV characteristics and the steering stability of the vehicle are improved. can be made

The X connecting portion of the connecting member may be connected to side surfaces of the pair of rear side members that intersect the swing axis of the suspension.

As a result, when the pair of rear side members receives a load in the direction of the swing axis through the suspension fixing portion, the connecting member is connected to the side surfaces of the pair of rear side members that intersect the swing axis that receives this load. ing. Therefore, the load received by the rear side member on either the left or right side can be efficiently received by the X connecting portion of the connecting member and dispersed to the side sill on the opposite side to be released. As a result, the vibration of the rear side member in the swing axis direction can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be reduced.

It is preferable that the X connecting portion of the connecting member is connected to the front end portion of each of the pair of side sills.

As a result, the pair of side sills and the pair of rear side members are connected, for example, diagonally by the X connecting portion of the connecting member, so that the torsional rigidity of the floor panel can be further increased. Furthermore, torsional vibration of the vehicle body caused by vibration transmitted from the suspension fixed portion to the rear side member can be efficiently transmitted from the front end portion of the side sill to the front member via the X connecting portion of the connecting member. Therefore, the vibration of the rear side member can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be reduced.

The pair of suspension fixing portions may be connected to the pair of rear side members so that the swing axis direction of the suspension is parallel to the X connecting portion of the connecting member.

In the above configuration, the suspension fixed portion is connected to the rear side member so that the swing axis direction of the suspension and the extending direction of the X connecting portion of the connecting member, such as the diagonal direction, are parallel to each other. Therefore, the vibration in the swing axis direction, which is transmitted from the suspension fixing portion to the rear side member on either the left or right side, can be efficiently transmitted to the side sill on the opposite side via the X connecting portion of the connecting member. Therefore, the vibration of the rear side member can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be further reduced.

The vehicle lower structure further includes one or more rear cross members extending in the vehicle width direction and connecting the pair of rear side members, and the X connection portion of the connecting member is connected to the pair of rear side members and the rear cross member. I hope it is.

As a result, the X connecting portion of the connecting member is supported not only by the rear side member but also by the rear cross member, so that the supporting rigidity of the connecting member can be increased, and vibration of the connecting member can be suppressed. In addition, the load transmitted to either the left or right rear side member via the suspension fixing portion is dispersed and released to the opposite rear side member and side sill via the X connecting portion of the connecting member and the rear cross member. can be done. Therefore, the vibration of the rear side member can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be further reduced.

The vehicle underbody structure described above further includes a front member positioned at the front portion of the lower side of the floor panel, the X-connecting portion of the connecting member being connected to the inner side surface of each of the pair of side sills, the connecting member further comprising: It is preferable to have a pair of front connecting portions branched inward in the vehicle width direction from the X connecting portion forward of the intersection of the X connecting portions and connected to the front member.

Thereby, the connecting member is connected to the side sill by the X connecting portion and is also connected to the front member via the front connecting portion. Therefore, the supporting rigidity of the connecting member can be increased, and vibration of the connecting member can be suppressed. Further, the vibration transmitted from the rear suspension fixed portion to the rear side member can be transmitted to the front member via the X connecting portion and the front connecting portion of the connecting member and dispersed. Therefore, the vibration of the rear side member can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be further reduced.

The front members include a pair of front side members located forward of the vehicle relative to the pair of side sills, a pair of torque boxes connecting the pair of front side members and the pair of side sills, and a connection connecting the pair of torque boxes. The pair of side sills and the pair of torque boxes are connected to each other by a predetermined first connection surface, the X connection portion of the connection member is connected to the first connection surface, and the pair of torque The box and the connecting member may be connected to each other by a predetermined second connecting surface, and the pair of front connecting portions may be connected to the second connecting surface.

Thereby, in the connecting member, the X connecting portion connected to the first connecting surface and the front connecting portion connected to the second connecting surface are connected via the torque box. Therefore, in the connecting member, the X connecting portion and the front connecting portion can be arranged adjacent to each other to reduce the branching angle between the X connecting portion and the front connecting portion. Therefore, the vibration transmitted from the rear side member on either the left or right side can be easily transmitted to the front member via the X connecting portion and the front connecting portion on the opposite side.

Furthermore, in the connecting member, the side sill and the torque box connected at the first connecting surface are connected to the X connecting portion, and the torque box and the connecting member connected at the second connecting surface are connected to the front connecting portion. Therefore, the supporting surfaces of the X connecting portion and the front connecting portion are increased, so that the supporting rigidity of the connecting member can be increased, and the vibration of the connecting member can be suppressed.

The connecting member may further include a pair of intermediate connecting portions that connect positions in front of and behind the intersection of the X connecting portions in the longitudinal direction of the vehicle.

Thereby, the connecting member can connect the positions in front of and behind the crossing point of the X connecting portion over the vehicle front-rear direction by the intermediate connecting portion. Therefore, the rigidity of the connecting member can be increased, and vibration of the connecting member can be suppressed.

The front end portions of the pair of intermediate connecting portions of the connecting member overlap the rear end portions of the pair of front connecting portions via the X connecting portion in the longitudinal direction of the vehicle, and the connecting member further extends inside the X connecting portion. It is preferable to have a bridging portion that bridges the front ends of the pair of intermediate connecting portions and the rear ends of the pair of front connecting portions in the longitudinal direction of the vehicle.

As a result, in the connecting member, the rear end portion of the front connecting portion and the front end portion of the intermediate connecting portion are bridged by the bridging portion arranged inside the X connecting portion. Vibration can be suppressed between Therefore, in the above configuration, the load can be efficiently transmitted in the longitudinal direction of the vehicle between the front member and the pair of rear side members via the front connecting portion, the X connecting portion and the intermediate connecting portion of the connecting member.

The one or more rear cross members have a first rear cross member that extends in the vehicle width direction and connects positions behind the intersection of the X connecting portions of the connecting members, and the pair of intermediate connecting portions. The rear end portion may be connected to the first rear cross member at a predetermined connection area, and further connected to the X connection portion at a position adjacent to the connection area.

As a result, the X connecting portion of the connecting member is connected not only to the rear side member but also to the first rear cross member, so that the supporting rigidity of the X connecting portion can be increased, and vibration of the connecting member can be suppressed. In addition, in the connecting member, when a load or vibration is transmitted from the front to the X connecting portion via the intermediate connecting portion, the load or vibration is dispersed not only to the X connecting portion but also to the first rear cross member so as to escape. can be done. Furthermore, since the intermediate connecting portion and the X connecting portion are connected at a position adjacent to the connecting region of the intermediate connecting portion and the first rear cross member, the connection rigidity of the intermediate connecting portion, the first rear cross member and the X connecting portion can increase

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these examples are merely examples for facilitating understanding of the invention, and do not limit the invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are given the same reference numerals to omit redundant description, and elements that are not directly related to the present invention are omitted from the drawings. do.

FIG. 1 is a bottom view showing a vehicle lower structure 100 according to an embodiment of the invention. FIG. 2 shows a portion of the vehicle undercarriage 100 of FIG. In the drawing, the vehicle lower structure 100 is shown as viewed from below the vehicle. In each figure below, the front and rear directions of the vehicle are indicated by arrows Front and Back, the left and right directions of the vehicle width are indicated by arrows Left and Right, and the vertical directions of the vehicle are indicated by arrows Up and Down.

A vehicle lower structure 100 includes a floor panel 102 that forms the floor surface of the vehicle, a pair of side sills 104 and 106, and a pair of rear side members 108 and 110. As shown in FIG. Since the vehicle lower portion structure 100 has a symmetrical structure as shown in FIG. 1, only the structure on the right side in the vehicle width direction will be described below unless particularly necessary.

The pair of side sills 104 and 106 are spaced apart in the vehicle width direction and extend in the vehicle front-rear direction along edges 112 and 114 of the floor panel 102 . The pair of rear side members 108, 110 are arranged on the inside of the pair of side sills 104, 106 in the vehicle width direction, extend forward of the vehicle from a rear end 116 of the vehicle, and extend toward the rear end portions 118, 118 of the pair of side sills 104, 106. 120.

The vehicle lower structure 100 further includes a pair of suspension fixing portions 122 and 124 , a front member 126 and a connecting member 128 . The pair of suspension fixing portions 122, 124 are connected to the pair of rear side members 108, 110, and fix swinging suspensions for rear wheels (not shown).

Also, the suspension fixing portion 122 is passed through by a swing shaft Sa of the suspension (see FIG. 2(a)). Note that FIG. 2A illustrates the structure of the suspension fixing portion 122 and its surroundings. The swing axis Sa passing through the suspension fixing portion 122 is inclined toward the front side of the vehicle toward the inner side in the vehicle width direction, and this direction is defined as the swing axis direction. Therefore, the rear side member 108 connected to the suspension fixing portion 122 receives a load in the swing axis direction from the suspension through the suspension fixing portion 122 during running of the vehicle, for example.

The front member 126 is a member located in the lower front portion of the floor panel 102 and has a pair of front side members 130 and 132 , a pair of torque boxes 134 and 136 and a connecting member 138 . The pair of front side members 130, 132 are located in front of the vehicle relative to the pair of side sills 104, 106 and extend in the longitudinal direction of the vehicle. A pair of torque boxes 134 , 136 connect the pair of front side members 130 , 132 and the pair of side sills 104 , 106 . A connecting member 138 connects the pair of torque boxes 134 and 136 .

The pair of side sills 104 and 106 and the pair of torque boxes 134 and 136 are connected to each other by predetermined first connection surfaces 140 and 142 . A pair of torque boxes 134 and 136 and a connecting member 138 are connected to each other by predetermined second connecting surfaces 144 and 146 . A suspension frame 148 included in the front member 126 overlaps the second connecting surfaces 144 and 146 from below the vehicle as shown.

The connecting member 128 has an X connecting portion 150, a pair of front connecting portions 152,154, and a pair of intermediate connecting portions 156,158. The X connecting portion 150 extends obliquely rearward from each of the pair of side sills 104 and 106 on the lower side of the floor panel 102, intersects each other at a predetermined intersection point 160, and further connects to each of the rear side members 108 and 110 on the opposite side. be done.

The X connecting portion 150 also has a pair of side sill connecting portions 162 and 164 and a pair of rear connecting portions 166 and 168 . The pair of side sill connecting portions 162, 164 extend obliquely forward from the intersection 160 toward the front ends 170, 172 of the pair of side sills 104, 106 and the first connecting surfaces 140, 142, and these front ends 170, 172 and the first connecting surfaces 140 , 142 .

Vehicle undercarriage 100 further comprises a first rear cross member 174 and a second rear cross member 176 . The first rear cross member 174 extends in the vehicle width direction and connects front ends 178 and 180 of the pair of rear side members 108 and 110 . As shown, the second rear cross member 176 is spaced behind the first rear cross member 174 and extends in the vehicle width direction to connect the pair of rear side members 108 and 110 .

The pair of rear connecting portions 166, 168 of the X connecting portion 150 extends obliquely rearward from the intersection 160 toward the front ends 178, 180 of the pair of rear side members 108, 110. 180.

Therefore, in the vehicle lower structure 100 , the pair of side sills 104 , 106 and the pair of rear side members 108 , 110 are diagonally connected under the floor panel 102 by the X connecting portions 150 of the connecting member 128 . Therefore, the torsional rigidity of the floor panel 102 can be further enhanced.

Further, in the vehicle lower structure 100, the torsional vibration of the vehicle body caused by the vibration transmitted from the suspension fixing portions 122, 124 to the rear side members 108, 110 is transferred from the side sills 104, 106 to the front side sills 104, 106 via the X connecting portion 150 of the connecting member 128. It can be efficiently communicated to members 126 . Therefore, the vibration of the rear side members 108 and 110 can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be reduced.

The front ends 178, 180 of the pair of rear side members 108, 110 are joined to the inner side portions of the rear ends 118, 120 of the pair of side sills 104, 106 positioned on the outside in the vehicle width direction. Therefore, the pair of rear side members 108 and 110 are sandwiched in the vehicle width direction by the pair of side sills 104 and 106 having high rigidity. Accordingly, in the vehicle lower portion structure 100, the vibration of the pair of rear side members 108, 110 can be suppressed more sufficiently.

Further, the pair of rear connecting portions 166, 168 of the X connecting portion 150 are also connected to the first rear cross member 174 and the second rear cross member 176 shown in FIG.

The pair of intermediate connecting portions 156 and 158 connect the pair of side sill connecting portions 162 and 164 and the pair of rear connecting portions 166 and 168 in the longitudinal direction of the vehicle at positions before and after the intersection 160 of the X connecting portion 150 . . As a result, the connecting member 128 can be connected in the longitudinal direction of the vehicle by the intermediate connecting portions 156 and 158 at positions in front of and behind the intersection 160 of the X connecting portion 150, so that rigidity can be increased and vibration can be suppressed. be able to.

Thus, in the vehicle lower structure 100, the pair of rear connecting portions 166, 168 of the X connecting portion 150 of the connecting member 128 are connected not only to the rear side members 108, 110 but also to the first rear cross member 174 and the second rear cross member 176. Supported. Therefore, the supporting rigidity of the connecting member 128 can be increased, and the vibration of the connecting member 128 can be suppressed.

Further, in the vehicle lower structure 100, the load transmitted to either the left or right rear side members 108, 110 via the suspension fixing portions 122, 124 is transferred to the X connecting portion 150 of the connecting member 128, the first rear cross member 174 and the Via the second rear cross member 176, the air can be dispersed to the opposite rear side members 108, 110 and the side sills 104, 106 to escape. Therefore, the vibration of the rear side members 108, 110 can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be further reduced.

Further, the pair of front connecting portions 152 and 154 of the connecting member 128 branch inward in the vehicle width direction from the pair of side sill connecting portions 162 and 164 ahead of the crossing point 160 of the X connecting portion 150 to form a second connecting surface 144. , 146 (see FIG. 2(b)). Note that FIG. 2B illustrates the structure of the front connecting portion 152 of the connecting member 128, the side sill connecting portion 162, and their surroundings.

In the connecting member 128, as shown in FIG. 1, a pair of side sill connecting portions 162, 164 of the X connecting portion 150 connected to the first connecting surfaces 140, 142 and a pair of side sill connecting portions 162, 164 connected to the second connecting surfaces 144, 146 are provided. Front connecting portions 152 and 154 are connected via a pair of torque boxes 134 and 136 . As a result, the connecting member 128 can arrange the pair of side sill connecting portions 162, 164 and the pair of front connecting portions 152, 154 of the X connecting portion 150 adjacent to each other. A branching angle between the pair of front connecting portions 152 and 154 can be reduced. Therefore, vibrations transmitted from the rear side members 108, 110 on either the left or right side can be easily transmitted to the front member 126 via the side sill connecting portions 162, 164 and the front connecting portions 152, 154 on the opposite side.

In the connecting member 128, a pair of side sills 104, 106 and a pair of torque boxes 134, 136 connected by first connecting surfaces 140, 142 are connected to a pair of side sill connecting portions 162, 164, and a second connecting surface 144, A pair of front links 152 , 154 are connected to a pair of torque boxes 134 , 136 and a connecting member 138 connected at 146 . Therefore, in the vehicle lower structure 100, the supporting surfaces of the pair of front connecting portions 152, 154 and the pair of side sill connecting portions 162, 164 of the X connecting portion 150 are increased. 128 vibration can be suppressed.

Further, the X connecting portion 150 of the connecting member 128 has the rear connecting portion 166 connected to the side surface 182 of the rear side member 108 as shown in FIG. 2(a). A side surface 182 of the rear side member 108 intersects the swing axis Sa of the suspension.

Therefore, when the rear side members 108 and 110 on either the left or right side receive a load in the swing axis direction via the suspension fixing portions 122 and 124, the load is transferred to the pair of X connecting portions 150 of the connecting member 128. can be efficiently received by the rear connecting portions 166, 168 on the other side and dispersed to the side sills 104, 106 on the opposite side to escape. As a result, in the vehicle lower structure 100, the vibration of the rear side members 108, 110 in the swing axis direction can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be reduced.

In the connecting member 128, as shown in FIG. 2(a), the rear connecting portion 166 of the X connecting portion 150 extends toward the corner portion 184 where the rear side member 108 and the second rear cross member 176 are connected. 184 are overlapped and joined. In this manner, in the connecting member 128, the rear connecting portion 166 is connected to the corner portion 184 of the connecting portion between the rear side member 108 and the second rear cross member 176 in addition to the side surface 182 of the rear side member 108, thereby improving connection rigidity. can be made

Further, in the vehicle lower structure 100, the rear connecting portion 166 of the X connecting portion 150 and the suspension fixing portion 122 are arranged adjacent to each other on the rear side member 108 as shown in FIG. 2(a). The rear connecting portion 166 is connected to the rear side member 108 with a connection width La with respect to the corner portion 184, and is connected to the second rear cross member 176 with a connection width Lb. A bolt shaft (not shown) of the suspension fixing portion 122 is positioned within the connection width La of the rear side member 108 .

As shown in FIG. 2(b), the side sill connecting portion 162 of the X connecting portion 150 extends toward a corner portion 186 of the side sill 104 and the first connecting surface 140 of the torque box 134, and overlaps the corner portion 188 to join. It is The side sill connecting portion 162 is connected to the inner side surface 188 of the side sill 104 with a connection width Lc, and further connected to the torque box 134 with a connection width Ld. Thereby, the connection rigidity of the side sill connecting portion 162 can be improved.

The front connecting portion 152 of the connecting member 128 extends toward the corner 190 of the second connecting surface 144 of the torque box 132 and the connecting member 138 as shown in FIG. It is The front connecting portion 152 is connected to the torque box 134 with a connection width Le, and further connected to the connecting member 138 with a connection width Lf. Thereby, the connection rigidity of the front connecting portion 152 can be improved.

The front link 152 is also attached to the suspension frame 148 at attachment points 192 . Therefore, the front connecting portion 152 can receive the load transmitted from the suspension (not shown) to the suspension frame 148 via the mounting point 192 and transmit the load to the X connecting portion 150 for distribution. The front end portion 193 of the front connecting portion 152 extends linearly in the vehicle front-rear direction as shown in FIG. may be

FIG. 3 is a diagram showing another part of the vehicle undercarriage 100 of FIG. FIG. 3(a) is a diagram showing the structure of the suspension fixing portion 124 and its surroundings. FIG. 3(b) is a diagram of the vehicle lower structure 100 of FIG. 3(a) with the intermediate connecting portion 158 of the connecting member 128 omitted.

A rear end portion 194 of the intermediate connecting portion 158 is joined to a front surface 198, a lower surface 200 and a rear surface 202 of the first rear cross member 174 at a predetermined connection area 196 as shown in FIG. It is connected to the rear link 168 of the X link 150 at another connection area 204 at an adjacent position.

The vehicle undercarriage 100 further comprises truss structures 206, 208 shown in FIG. 3(a). Truss structure 206 is formed by being surrounded by first rear cross member 174 , front end portion 180 of rear side member 110 and rear connecting portion 168 , and can increase the rigidity of these members and floor panel 102 . The truss structure 208 is formed by being surrounded by the side sill connecting portion 164 and the rear connecting portion 168 of the X connecting portion 150 and the intermediate connecting portion 158, and the rigidity of each of these members and the floor panel 102 can be increased. can.

As shown in FIG. 3(b), the rear end 210 of the rear connecting portion 168 is joined to the front surface 198, lower surface 200 and rear surface 202 of the first rear cross member 174 at the connection area 196. As shown in FIG. Therefore, in the connection region 196, three pieces are joined by the rear end portion 194 of the intermediate connecting portion 158, the rear end portion 210 of the rear connecting portion 168, and the first rear cross member 174 to increase the connection rigidity of these members. be able to.

Thus, in the vehicle lower structure 100, the rear connecting portion 168 of the X connecting portion 150 of the connecting member 128 is connected not only to the rear side member 110 but also to the first rear cross member 174, so that the support rigidity of the X connecting portion 150 is increased. can be increased, and vibration of the connecting member 128 can be suppressed. Further, in connection member 128 , when a load or vibration is transmitted from the front to X connection portion 150 via intermediate connection portion 158 , the load or vibration is transferred not only to X connection portion 150 but also to first rear cross member 174 . You can disperse and escape.

Furthermore, the rear end portion 194 of the intermediate connecting portion 158 and the rear connecting portion 168 of the X connecting portion 150 are connected at a position adjacent to the connection region 196 between the rear end portion 194 of the intermediate connecting portion 158 and the first rear cross member 174 . Therefore, the connection rigidity of the intermediate connecting portion 158, the first rear cross member 174 and the rear connecting portion 168 of the X connecting portion 150 can be increased.

FIG. 4 is a top view showing a portion of the vehicle undercarriage 100 of FIG. FIG. 4( a ) shows a portion of the vehicle undercarriage 100 with the floor panel 102 seen through. FIG. 4(b) shows the connecting member 128 of FIG. 4(a).

The vehicle undercarriage 100 further comprises a center tunnel 212, a front seat cross member 214 and a rear seat cross member 216, as shown in FIG. 4(a). The center tunnel 212 extends upward in the longitudinal direction of the vehicle at the center of the floor panel 102 in the vehicle width direction.

The front seat cross member 214 is a member that extends in the vehicle width direction and connects the pair of side sills 104 and 106, and has a plurality of front seat mounting brackets 218 mounted on its upper surface. The rear seat cross member 216 is a member that is spaced behind the front seat cross member 214 and extends in the vehicle width direction to connect the pair of side sills 104 and 106 . A seat mounting bracket 220 is installed.

Here, the center tunnel 212 has a tunnel portion 222 raised upward from the floor panel 102 . For example, the amount of protrusion of the tunnel portion 222 from the floor panel 102 decreases toward the rear of the vehicle. Therefore, the floor panel 102 tends to vibrate in planes at a position behind the lower end 224 of the tunnel portion 222 shown in FIG. 4(a). Therefore, in the vehicle lower part structure 100, by arranging the intersection point 160 of the connecting member 128 at a position behind the lower end 224 of the tunnel portion 222, the surface vibration of the floor panel 102 can be suppressed.

In the connecting member 128 , the rear connecting portions 166 and 168 are arranged behind the rear seat cross member 216 while overlapping the intersection 160 with the rear seat cross member 216 . Therefore, planar vibration at a position behind the lower end 224 of the tunnel portion 222 in the floor panel 102 can be sufficiently suppressed.

Furthermore, in the connecting member 128, the rear seat mounting brackets 220a, 220b installed on the rear seat cross member 216 and the side sill connecting portions 162, 164 are vertically stacked near the intersection 160. . As a result, it is possible to increase the rigidity of the lower surface of the front seat (not shown) that receives a load when the passenger sits on the seat, suppress vibrations transmitted to the passenger, and improve NV characteristics. Moreover, since the rear seat mounting brackets 220a, 220b that receive the weight of the occupant and the side sill connecting portions 162, 164 are superimposed in the vertical direction near the intersection 160 of the connecting member 128, the side sill connecting portions 162, 164 are placed on the front side. Vibration transmitted to the occupant can be more sufficiently suppressed than when the seat mounting brackets 218 are stacked.

The rear seat mounting bracket 220 is not limited to the side sill connecting portions 162 and 164, and may be arranged so as to overlap the intermediate connecting portions 156 and 158 in the vertical direction. It may be arranged so as to vertically overlap the predetermined region 226 surrounded by the connecting portion 166 .

The connecting member 128 further includes a plurality of bridging portions 228a, 228b, 230a, 230b, 232a, 232b as shown in FIG. 4(b). A front end portion 234 of the intermediate connecting portion 156 overlaps a rear end portion 236 of the front connecting portion 152 via the side sill connecting portion 162 of the X connecting portion 150 in the vehicle longitudinal direction. The bridging portions 228a and 228b are arranged inside the side sill connecting portion 162, and serve as bulkheads by bridging a front end portion 234 of the intermediate connecting portion 156 and a rear end portion 236 of the front connecting portion 152 in the longitudinal direction of the vehicle. It is functioning. As a result, the rigidity between the front connecting portion 152 and the intermediate connecting portion 156 can be increased, and the transmission efficiency of vibration and load can be increased.

A front end portion 238 of the intermediate connecting portion 158 overlaps a rear end portion 240 of the front connecting portion 154 via the side sill connecting portion 164 of the X connecting portion 150 in the vehicle longitudinal direction. The bridging portions 230a and 230b are arranged inside the side sill connecting portion 164, and serve as bulkheads by bridging a front end portion 238 of the intermediate connecting portion 158 and a rear end portion 240 of the front connecting portion 154 in the longitudinal direction of the vehicle. It is functioning. As a result, the rigidity between the front connecting portion 154 and the intermediate connecting portion 158 can be increased, and the transmission efficiency of vibration and load can be increased.

A front end portion 242 of the rear connecting portion 168 overlaps a rear end portion 244 of the side sill connecting portion 162 in the vehicle front-rear direction via the intersection 160 of the X connecting portion 150 . The bridging portions 232a and 232b are arranged inside the crossing portion 160 of the X connecting portion 150, and bridge the front end portion 242 of the rear connecting portion 168 and the rear end portion 244 of the side sill connecting portion 162 in the longitudinal direction of the vehicle. functions as a bulkhead. As a result, the rigidity between the rear connecting portion 168 and the side sill connecting portion 162 can be increased, and the transmission efficiency of vibration and load can be improved.

Therefore, in the vehicle lower structure 100, between the front member 126 and the pair of rear side members 108, 110, the front connecting portions 152, 154, the X connecting portion 150, and the intermediate connecting portions 156, 158 of the connecting member 128 are connected to the vehicle. A load can be efficiently transmitted in the longitudinal direction.

Although the connecting member 128 and the rear side members 108 and 110 are arranged below the floor panel 102 , they may be arranged above the floor panel 102 .

FIG. 5 is a diagram schematically showing a modification of the vehicle lower structure 100 of FIG. In the vehicle lower structure 100A shown in FIG. 5(a), the rear connecting portion 166 and the suspension fixing portion 122 of the X connecting portion 150 of the connecting member 128 are connected to the regions of the rear side member 108 facing each other in the vehicle width direction, that is, the side surfaces 246 and 248. connected to each other. That is, the rear connecting portion 166 of the X connecting portion 150 and the suspension fixing portion 122 are arranged to face each other with the rear side member 108 therebetween. Even with such a vehicle lower portion structure 100A, it is possible to suppress the vibration of the swing axis Sa of the rear side member 108 in the swing axis direction.

In the vehicle lower structure 100B shown in FIG. 5(b), the rear connecting portion 166 of the X connecting portion 150 of the connecting member 128 and the suspension fixing portion 122 are attached to the regions facing each other in the vertical direction of the rear side member 108, that is, the upper surface 250 and the lower surface 252. connected to each other. That is, the rear connecting portion 166 of the X connecting portion 150 and the suspension fixing portion 122 are arranged adjacent to each other on the rear side member 108 . Even with such a vehicle lower portion structure 100B, it is possible to suppress the vibration of the swing axis Sa of the rear side member 108 in the swing axis direction.

FIG. 6 is a diagram showing another modification of the vehicle lower structure 100 of FIG. 2(a). A vehicle lower structure 100</b>C of the modification differs from the vehicle lower structure 100 in that a suspension fixing portion 122</b>A is provided instead of the suspension fixing portion 120 .

The suspension fixing portion 122A is mounted on the rear side so that the swing axis direction of the suspension swing shaft Sb (not shown) is parallel to the extending direction of the rear connecting portion 166 of the X connecting portion 150 of the connecting member 128, for example, the diagonal direction T. It is connected to member 108 .

Thus, in the vehicle lower structure 100C, the suspension fixing portion 122A is attached to the rear side member 108 so that the swing axis direction of the swing shaft Sb of the suspension and the diagonal direction T of the rear connecting portion 166 of the X connecting portion 150 are parallel to each other. Connected. Although not shown, in the vehicle lower structure 100C, the suspension fixing portion 124 is also connected to the rear side member 110 so as to be parallel to the diagonal direction of the rear connecting portion 168. As shown in FIG.

Therefore, in the vehicle lower structure 100C, vibrations in the swing axis direction transmitted from the suspension fixing portions 122A, 124 to the left or right rear side members 108, 110 are transferred to the opposite side via the X connecting portion 150 of the connecting member 128. side sills 104, 106. Therefore, the vibration of the rear side members 108, 110 can be suppressed, and the torsional vibration and floor vibration caused by this vibration can be further reduced.

FIG. 7 is a diagram showing still another modification of the vehicle lower structure 100 of FIG. A vehicle lower structure 100D shown in FIG. 7A differs from the vehicle lower structure 100 in that a connecting member 128A is provided instead of the connecting member 128. As shown in FIG.

The connecting member 128A has an X connecting portion 150A, a pair of front connecting portions 162A and 164A, and a pair of intermediate connecting portions 156A and 158A. The X connecting portion 150A has a pair of side sill connecting portions 162A, 164A and a pair of rear connecting portions 166A, 168A. The X connecting portion 150A connects the pair of side sills 104, 106 and the pair of rear side members 108, 110 so as to cross each other on the lower side of the floor panel 102. However, as shown in FIG. are not linked.

That is, the pair of side sill connecting portions 162A, 164A are located at a predetermined position on the pair of side sills 104, 106 that are positioned behind the first connecting surfaces 140, 142 from the intersection 160A rather than the first connecting surfaces 140, 142 described above. It extends diagonally forward toward 254 and 256 and is connected to these predetermined locations 254 and 256 .

The pair of rear connecting portions 166A, 168A extend obliquely rearward from the intersection 160A toward the front ends 178, 180 of the pair of rear side members 108, 110 and are connected to the front ends 178, 180. .

The pair of front connecting portions 152A and 154A are branched inward in the vehicle width direction from the pair of side sill connecting portions 162A and 164A forward of the intersection 160A of the X connecting portion 150A and connected to the front member 126. The pair of intermediate connecting portions 156A, 158A connect the pair of side sill connecting portions 162A, 164A and the pair of rear connecting portions 166A, 168A in the longitudinal direction of the vehicle at positions in front of and behind the intersection 160A.

Thus, in the vehicle lower structure 100C, although the pair of side sills 104, 106 and the pair of rear side members 108, 110 are not connected diagonally below the floor panel 102 by the X connecting portion 150A of the connecting member 128A, Since they are connected so as to intersect, the torsional rigidity of the floor panel 102 can be increased.

A vehicle lower structure 100E shown in FIG. 7B differs from the vehicle lower structure 100 in that a connecting member 128B is provided instead of the connecting member 128. As shown in FIG. The connecting member 128B has a pair of floor side members 258, 260, an X member 262, and a pair of side sill connecting portions 162B, 164B.

The pair of floor side members 258, 260 are connected to the front member 126 at their front ends 264, 266 below the floor panel 102 as shown in FIG. It connects to the front ends 178,180 of 108,110. Thus, the pair of floor side members 258, 260 connect the front member 126 and the pair of rear side members 108, 110. As shown in FIG.

The X member 262 extends in an X shape between the pair of floor side members 258 and 260 and is connected to the pair of floor side members 258 and 260 respectively. The pair of side sill connecting portions 162B, 164B branch outward in the vehicle width direction from the pair of floor side members 258, 260 and are connected to the first connecting surfaces 140, 142. As shown in FIG.

The connecting member 128B further includes a plurality of bridging portions 272a, 272b, 274a, 274b, 276, 278 as shown in FIG. 7(b). A front end portion 280 of the X member 262 overlaps a rear end portion 282 of the side sill connecting portion 162B via the floor side member 258 in the extending direction of the X member 262 . The bridging portions 272a and 272b are arranged inside the floor side member 258 and function as bulkheads by bridging the front end portion 280 of the X member 262 and the rear end portion 282 of the side sill connecting portion 162B in the extending direction. ing. As a result, the rigidity between the X member 262 and the side sill connecting portion 162B can be increased, and the transmission efficiency of vibration and load can be increased.

A front end portion 284 of the X member 262 overlaps a rear end portion 286 of the side sill connecting portion 164B via the floor side member 260 in the extending direction of the X member 262 . The bridging portions 274a and 274b are arranged inside the floor side member 260 and function as bulkheads by bridging the front end portion 284 of the X member 262 and the rear end portion 286 of the side sill connecting portion 164B in the extending direction. ing. As a result, the rigidity between the X member 262 and the side sill connecting portion 164B can be increased, and the transmission efficiency of vibration and load can be increased.

The rear end portion 288 of the X member 262 overlaps the rear end portion 268 of the floor side member 258 in the extending direction of the X member 262 . The bridging portion 276 is arranged inside the floor side member 258 and functions as a bulkhead by bridging the rear end portion 288 of the X member 262 and the rear end portion 268 of the floor side member 258 in the extension direction. there is As a result, the rigidity between the X member 262 and the floor side member 258 can be increased, and the transmission efficiency of vibration and load can be increased.

A rear end portion 290 of the X member 262 overlaps a rear end portion 270 of the floor side member 260 in the extending direction of the X member 262 . The bridging portion 278 is arranged inside the floor side member 260 and functions as a bulkhead by bridging the rear end portion 290 of the X member 262 and the rear end portion 270 of the floor side member 260 in the extension direction. there is As a result, while increasing the rigidity between the X member 262 and the floor side member 260, the transmission efficiency of vibration and load can be increased.

Therefore, in the vehicle lower structure 100E, the front member 126 and the pair of rear side members 108, 110 are interposed via the pair of floor side members 258, 260 of the connecting member 128B, the pair of side sill connecting portions 162B, 164B, and the X member 262. Therefore, the load can be efficiently transmitted in the longitudinal direction of the vehicle. Although the connecting member 128B differs from the connecting member 128 shown in FIG. 1 in the number and shape of each constituent member, it has the same shape when the constituent members are combined. have the same function. Although the pair of floor side members 258 and 260 are arranged below the floor panel 102 , they may be arranged above the floor panel 102 .

As described above, in the vehicle lower structures 100, 100A to 100E, the torsional rigidity of the floor panel 102 can be increased by the connection members 128, 128A, 128B. Further, in the vehicle lower structures 100, 100A to 100E, the load transmitted to the left or right rear side members 108, 110 via the connecting members 128, 128A, 128B is distributed to the side sills 104, 106 on the opposite side. Further, the load transmitted from the front member 126 to the side sills 104, 106 on either the left or right side can be dispersed to the rear side members 108, 110 on the opposite side and released.

Therefore, according to the vehicle lower structures 100, 100A to 100E, the torsional vibration of the floor panel 102 is suppressed, and the torsional vibration of the vehicle body caused by the vibration of the rear side members 108, 110 and the floor vibration of the floor panel 102 are reduced. , the NV characteristics and the steering stability of the vehicle can be improved.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope described in the claims, and these also belong to the technical scope of the present invention. Understood.

INDUSTRIAL APPLICABILITY The present invention can be used for vehicle undercarriages.

100, 100A to 100E Vehicle lower structure 102 Floor panel 104, 106 Side sill 108, 110 Rear side member 112, 114 Edge of floor panel 116 Rear end of vehicle 118, 120 Side sill Rear end 122, 122A, 124 Suspension fixing part 126 Front member 128, 128A, 128B Connection member 130, 132 Front side member 134, 136 Torque box 138 Connection member 140, 142 First connection surface 144, 146 Second connection surface 148 Suspension frame 150, 150A X connection portion 152, 152A, 154, 154A Front connection portion 156, 156A, 158, 158A Intermediate Connecting portions 160, 160A... Crossing points 162, 162A, 162B, 164, 164A, 164B... Side sill connecting parts 166, 166A, 168, 168A... Rear connecting parts 170, 172... Front ends of side sills 174... Third 1 rear cross member 176 second rear cross member 178, 180 front end of rear side member 182, 246, 248 side surface of rear side member 184, 186, 190 corner 188 inner side surface of side sill Reference numeral 192: Attachment point 193: Front end of front connecting portion 194: Rear end of intermediate connecting portion 196, 204: Connection region 198: Front surface of first rear cross member 200: Lower surface of first rear cross member , 202... Rear surface of first rear cross member 206, 208... Truss structure 210... Rear end of rear connecting portion 212... Center tunnel 214... Front side seat cross member 216... Rear side seat cross member 218... front seat mounting brackets 220, 220a, 220b rear seat mounting brackets 222 tunnel portion 224 lower end of tunnel portion 226 predetermined regions 228a, 228b, 230a, 230b, 232a, 232b, 272a, 272b, 274a, 274b, 276, 278... Bridge portion 234, 238... Front end portion of intermediate connecting portion 236, 240... Rear end portion of front connecting portion 242... Front end portion of rear connecting portion 244, 282, 286... Side sill Rear end portion of connecting portion 250... Upper surface of rear side member 252... Lower surface of rear side member 254, 256... Predetermined portion of side sill 258, 260... Floor side member 262... X member 264, 266... Floor side member Front ends of members 268, 270 Rear ends of floor side members 280, 284 Front ends of X members 288, 290 Rear ends of X members

Claims (10)

A vehicle undercarriage comprising a floor panel forming a floor of the vehicle, the vehicle undercarriage further comprising:
a pair of side sills extending in the longitudinal direction of the vehicle along edges of the floor panel;
a pair of rear side members extending forward of the vehicle from a rear end of the vehicle and connected to rear ends of the pair of side sills;
a pair of suspension fixing parts connected to the pair of rear side members and fixing a swinging suspension for the rear wheels;
a connecting member having an X connecting portion that extends obliquely rearward from each of the pair of side sills, crosses each other, and is connected to each of the pair of rear side members;
The X connecting portion of the connecting member and the pair of suspension fixing portions are adjacent to each other on the pair of rear side members, or face each other across the pair of rear side members. Vehicle undercarriage. 2. The vehicle lower structure according to claim 1, wherein the X-connecting portions of the connecting members are connected to side surfaces of the pair of rear side members that intersect the swing axis of the suspension. 3. The vehicle lower structure according to claim 1, wherein the X connecting portion of the connecting member is connected to the front end portion of each of the pair of side sills. 4. The pair of suspension fixing portions according to claim 3, wherein the pair of suspension fixing portions are connected to the pair of rear side members so that the swing axis direction of the suspension is parallel to the X connecting portion of the connecting member. Vehicle undercarriage. The vehicle lower structure further includes one or more rear cross members extending in the vehicle width direction and connecting the pair of rear side members,
The vehicle lower structure according to any one of claims 1 to 4, wherein the X connecting portion of the connecting member is connected to the pair of rear side members and the rear cross member. The vehicle undercarriage further comprises:
comprising a front member positioned in front of the lower side of the floor panel;
The X connecting portion of the connecting member is connected to the inner side surface of each of the pair of side sills,
3. The connecting member further has a pair of front connecting portions branching inward in the vehicle width direction from the X connecting portion forward of the intersection of the X connecting portions and connected to the front member. 6. The vehicle lower structure according to any one of 1 to 5. The front member is
a pair of front side members located in front of the vehicle with respect to the pair of side sills;
a pair of torque boxes connecting the pair of front side members and the pair of side sills;
a connecting member that connects the pair of torque boxes,
The pair of side sills and the pair of torque boxes are connected to each other by predetermined first connection surfaces,
The X connecting portion of the connecting member is connected to the first connecting surface,
The pair of torque boxes and the connecting member are connected to each other by a predetermined second connecting surface,
7. The vehicle lower structure according to claim 6, wherein the pair of front connecting portions are connected to the second connecting surface. 8. The vehicle lower portion structure according to claim 6, wherein the connecting member further includes a pair of intermediate connecting portions that connect front and rear positions of the intersection of the X connecting portions in the longitudinal direction of the vehicle. Front end portions of the pair of intermediate connecting portions of the connecting member overlap rear end portions of the pair of front connecting portions via the X connecting portion in the vehicle front-rear direction, and
The connecting member further includes a bridge portion that is disposed inside the X connecting portion and bridges between the front end portions of the pair of intermediate connecting portions and the rear end portions of the pair of front connecting portions in the longitudinal direction of the vehicle. The vehicle undercarriage according to claim 8, characterized in that: The one or more rear cross members have a first rear cross member that extends in the vehicle width direction and connects a position behind the intersection of the X connecting portions of the connecting members,
The rear end portions of the pair of intermediate connecting portions are connected to the first rear cross member at a predetermined connecting region, and further connected to the X connecting portion at a position adjacent to the connecting region. The vehicle substructure according to claim 8 or 9.

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