Vehicle underbody structure

Abstract

To provide a vehicle lower part structure which can inhibit vibration of a suspension frame and a floor panel to improve steering stability and NV characteristics of a vehicle.SOLUTION: A vehicle lower part structure 100 includes: a floor panel 102 forming a floor surface of a vehicle; a front suspension frame 106 located at a front part of the floor panel; and floor side members 122, 124 fixed to the front suspension frame at an outer side in a vehicle width direction relative to a center in the vehicle width direction of the front suspension frame and extending to a vehicle rear. Each floor side member has at least two portions, a first portion 134, 136 and a second portion 138, 140 which are branched from the front suspension frame and extend to the vehicle rear. One of the at least two portions is branched from the suspension frame to the outer side in the vehicle width direction or an inner side in the vehicle width direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle underbody structure. [Background technology]

[0002] A vehicle such as an automobile is equipped with a vehicle understructure having, for example, a suspension frame of a front suspension, a front side member extending in the fore-and-aft direction of the vehicle at the front of the vehicle, and a floor side member extending in the fore-and-aft direction below a floor panel. In such a vehicle understructure, the suspension frame is supported by a plurality of members such as the front side member and the floor side member, thereby increasing the rigidity of the front of the vehicle and dispersing the impact transmitted to the front of the vehicle throughout the entire vehicle to suppress vibration.

[0003] On the other hand, when the vehicle turns, vibrations and loads (e.g., centrifugal force and inertial force) occur in the vehicle width direction. By distributing the vibrations and loads in the vehicle width direction, it is possible to suppress the vibration of the floor panel, for example, thereby improving the vehicle's noise and vibration (NV) characteristics and further increasing the vehicle's steering stability. For this reason, it is necessary to distribute the vibrations and loads acting in the vehicle's lower structure in the vehicle width direction.

[0004] Patent Document 1 describes a vehicle body structure that includes a suspension member 13 and a center side member 32. The center side member 32 is disposed on the inner side in the vehicle width direction of a side sill 29 disposed on the outer side in the vehicle width direction, and connects a front frame member 51 disposed in the front part of the vehicle body and a rear frame member 53 disposed in the rear part of the vehicle body.

[0005] Patent Document 1 describes that the center side member 32 extends outward in the vehicle width direction toward the rear of the vehicle and that the strength of the center side member 32 is set to be greater than the strength of the side sills 29, thereby improving the rigidity of the vehicle body. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-63758 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the vehicle body structure of Patent Document 1, the center side member 32 is provided with the longitudinal extension portion 4 of the suspension member 13. 5 is Therefore, the center side member 32 transmits loads (such as centrifugal force and inertial force of the vehicle) and vibrations having a vehicle width direction component that are transmitted to the suspension member 13 when the vehicle turns, through the longitudinal extension portion 4 of the suspension member 13. 5 However, in Patent Document 1, no special measures are taken to reduce such loads and vibrations. As a result, it is not possible to suppress the vibrations of the suspension member 13 (suspension frame) and floor panel that occur when the vehicle turns, making it difficult to improve the steering stability and NV characteristics of the vehicle.

[0008] In view of these problems, the present invention aims to provide a vehicle underbody structure that can suppress vibration of the suspension frame and floor panel, thereby improving the steering stability and NV characteristics of the vehicle. [Means for solving the problem]

[0009] In order to solve the above problems, a typical configuration of a vehicle understructure according to the present invention is a vehicle understructure having a floor panel that forms a floor surface of the vehicle, the vehicle understructure further comprising a suspension frame located at a front portion of the floor panel, and a floor side member fixed to the suspension frame on a side outer than the vehicle width center of the suspension frame and extending toward the rear of the vehicle, the floor side member having at least two portions branching off from the suspension frame and extending toward the rear of the vehicle, and one of the at least two portions branching off from the suspension frame toward the outer side or the inner side of the vehicle width. Effect of the Invention

[0010] According to the present invention, it is possible to provide a vehicle underbody structure that can suppress vibrations of a suspension frame and a floor panel and improve the steering stability and NV characteristics of the vehicle. [Brief description of the drawings]

[0011] [Figure 1] 1 is a bottom view showing a vehicle underbody structure according to an embodiment of the present invention. [Diagram 2] 2 is a diagram showing a state where a part of the vehicle underbody structure in FIG. 1 is viewed from diagonally below. [Diagram 3] 2 is a diagram showing another part of the vehicle underbody structure of FIG. 1 as viewed from diagonally below. FIG. [Figure 4] 2 is a diagram showing a modified example of the vehicle underbody structure of FIG. 1. [Diagram 5] 1. FIG. 4 is a diagram showing another modified example of the vehicle underbody structure of FIG. [Figure 6] 1. FIG. 4 is a diagram showing still another modified example of the vehicle underbody structure of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A typical configuration of a vehicle understructure according to one embodiment of the present invention is a vehicle understructure including a floor panel that forms a floor surface of the vehicle, the vehicle understructure further including a suspension frame located in front of the floor panel, and a floor side member fixed to the suspension frame outside the vehicle width center of the suspension frame and extending toward the rear of the vehicle, the floor side member having at least two portions that branch off from the suspension frame and extend toward the rear of the vehicle, and one of the at least two portions branches off from the suspension frame outside or inside the vehicle width direction.

[0013] In the above configuration, the suspension frame is fixed to the floor side member. Therefore, the floor side member is subjected to loads (such as centrifugal force and inertial force of the vehicle) and vibrations having a vehicle width component acting on the suspension frame, for example, when the vehicle turns. Therefore, the floor side member in the above configuration has at least two portions that branch off from the suspension frame and extend toward the rear of the vehicle, one of which branches off from the suspension frame to the outside or inside in the vehicle width direction.

[0014] Therefore, the floor side member can transmit the load and vibration received from the suspension frame to at least two parts branching from the suspension frame and extending rearward of the vehicle, and efficiently disperse and release the load and vibration to the rearward of the vehicle. Furthermore, if one part branches inward in the vehicle width direction and extends rearward of the vehicle, the inner side of the floor panel in the vehicle width direction is reinforced, so that floor vibration of the floor panel can be suppressed and torsional rigidity can be increased. On the other hand, if one part inclines outward in the vehicle width direction and branches rearward of the vehicle, the load and vibration can be released to the outer side in the vehicle width direction, and further, the inner side of the floor panel in the vehicle width direction can be reinforced by another part located inside the one part in the vehicle width direction. Therefore, floor vibration and torsional vibration of the floor panel can be suppressed. Therefore, according to the above configuration, vibration of the suspension frame and floor panel generated when the vehicle turns can be suppressed, and the steering stability and NV characteristics of the vehicle can be improved.

[0015] At least two portions of the floor side member preferably include a first portion that branches off from the suspension frame to the outside in the vehicle width direction and has an arc shape that convex outward in the vehicle width direction, and a second portion that branches off from the suspension frame to the inside in the vehicle width direction and has an arc shape that convex inward in the vehicle width direction.

[0016] In this way, the first and second parts of the floor side member are arc-shaped. Note that the term "arc-shaped" is not limited to a circular arc that is a part of a circle, but also includes an arc that is a part of an ellipse. Therefore, with the above configuration, it is possible to prevent the vibrations and loads transmitted from the suspension frame to the first and second parts from concentrating locally at the first and second parts, thereby improving the efficiency of transmission of the vibrations and loads.

[0017] An end face of the second portion is connected to a side surface of the first portion of the above-mentioned floor side member, and a protruding portion is formed in the second portion of the floor side member which protrudes from its underside toward the first portion and overlaps and is connected to the underside of the first portion, and the undersides of the first portion and the second portion are inclined so as to become higher or lower as they approach the suspension frame.

[0018] In this way, in the floor side member, the end face of the second part is connected to the side face of the first part, and further, the underside of the first part and the overhanging part that overhangs from the underside of the second part toward the first part are overlapped and connected, thereby increasing the connection rigidity between the first part and the second part. Note that connection includes a form in which each member is joined and a form in which they are fastened together with a bolt.

[0019] In addition, the floor side member is inclined so that the underside of the first portion and the underside of the second portion become higher or lower as they approach the suspension frame, so that the suspension frame can be fixed at the highest or lowest point of the underside of the first portion and the underside of the second portion.

[0020] As another example, assume that the rear end of the underside of the first part and the rear end of the underside of the second part are set at different heights from the locations of the undersides of the first part and the second part to which the suspension frame is fixed. Even in such a case, in the above configuration, the undersides of the first part and the second part are inclined so as to become higher or lower as they approach the suspension frame, so that load and vibration can be efficiently transmitted from the suspension frame to the rear end of the underside of the first part and the rear end of the underside of the second part.

[0021] The suspension frame may overlap the protruding portion of the second portion of the floor side member, whereby the first portion, the second portion and the suspension frame of the floor side member are connected in an overlapping manner.

[0022] According to the above configuration, the suspension frame, the underside of the first portion of the floor side member, and the protruding portion of the second portion can be connected by, for example, overlapping and joining, or fastening together with a bolt, etc. This increases the connection rigidity of the suspension frame, the first portion of the floor side member, and the second portion. In addition, since the underside of the first portion of the suspension frame, the floor side member, and the protruding portion of the second portion are connected by overlapping in the vertical direction, it becomes easier to transmit load and vibration from the suspension frame to the first portion and the second portion of the floor side member.

[0023] The above-mentioned vehicle underbody structure may further include a side sill extending in the fore-and-aft direction of the vehicle along the edge of the floor panel, a front side member located further forward of the side sill, and a torque box connecting the front side member and the side sill, and the floor side member may be connected to the torque box.

[0024] As a result, the floor side member is connected not only to the suspension frame but also to the torque box that connects the front side member and the side sill, so that the floor side member can transmit the load and vibration received from the suspension frame to the torque box, disperse them, and release them.

[0025] The above-mentioned vehicle undercarriage structure further includes a side sill extending in the fore-and-aft direction of the vehicle along the edge of the floor panel and positioned outboard in the vehicle width direction of a first portion of the floor side member, a lower cross member extending in the vehicle width direction below the floor panel and positioned rearward of the second portion of the floor side member, and a rear side member extending from the rear end of the vehicle toward the front of the vehicle and connected to the lower cross member, wherein the rear end of the first portion is connected to the inner side surface of the side sill in the vehicle width direction and the rear end of the second portion is connected to the lower cross member.

[0026] In this way, the rear end of the first portion branching off from the suspension frame is connected to the highly rigid side sill, and the rear end of the second portion is connected to the lower cross member. Therefore, the floor side member can transmit the load and vibration received from the suspension frame via the first and second portions to the side sill and lower cross member, dispersing the load and vibration and dissipating them throughout the vehicle. In addition, because the first portion is connected to the highly rigid side sill, vibration of the first portion can be suppressed.

[0027] As an example, when the rear end of the first portion is connected not only to the side sill but also to the lower cross member, and the rear end of the second portion is further connected to the rear end of the first portion, the rear end of the second portion is indirectly connected to the lower cross member. In this case, the floor side member can transmit and disperse load and vibration not only to the lower cross member but also to the side sill via the second portion. Also, when the rear end of the second portion is directly connected to the lower cross member, the floor side member can transmit and disperse load and vibration not only to the lower cross member but also to the rear side member via the second portion.

[0028] The above-mentioned vehicle undercarriage structure may further include a center tunnel that extends upward in the fore-and-aft direction of the vehicle at the center of the floor panel in the vehicle width direction, and the second portion of the floor side member may extend toward the rear of the vehicle so as to gradually approach and become adjacent to the center tunnel from the suspension frame.

[0029] As a result, the floor side member can transmit and disperse the load and vibration transmitted from the suspension frame to the second portion to the center tunnel. This makes it possible to suppress floor vibration of the floor panel. Also, since the vibration surface of the floor panel can be partitioned in the vehicle width direction by the center tunnel, surface vibration of the floor panel can be suppressed. Note that "the second portion is adjacent to the center tunnel" includes a configuration in which the second portion is disposed close to but not in contact with the center tunnel, or abuts or is connected to the center tunnel.

[0030] The above vehicle undercarriage structure may further include a bridging portion disposed inside the center tunnel and bridging between the two side walls of the center tunnel in the vehicle width direction, and the bridging portion may be adjacent to the location of the second portion of the floor side member that is most convex toward the inside in the vehicle width direction.

[0031] As a result, the floor side member can transmit the load and vibration transmitted from the suspension frame to the second portion to the portion of the center tunnel where the bridge portion is located inside and has high rigidity. Also, by locating the bridge portion inside the center tunnel, the rigidity of the floor panel can be increased. Therefore, floor vibration of the floor panel can be suppressed.

[0032] The above-mentioned vehicle undercarriage structure further includes an upper cross member extending in the vehicle width direction above the floor panel, and the portion of the first portion that is most convex outward in the vehicle width direction and the portion of the second portion that is most convex inward in the vehicle width direction overlap the upper cross member via the floor panel and are joined to the underside of the upper cross member together with the floor panel.

[0033] As a result, the floor side member can transmit and disperse the load and vibration transmitted from the suspension frame to the first and second sections to the upper cross member. In addition, because the first and second sections of the floor side member are connected by the upper cross member, the rigidity of each of these members can be increased, and vibration of each of these members can be suppressed. EXAMPLES

[0034] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown. In the present embodiment, connection includes a form in which the members to be connected are integrated with each other, and a form in which separate members are joined together.

[0035] 1 is a bottom view showing a vehicle underbody structure 100 according to an embodiment of the present invention. The figure shows the vehicle underbody structure 100 as seen from below the vehicle. In each of the figures below, the front-rear direction of the vehicle is indicated by arrows Front and Back, the left and right directions of the vehicle width are indicated by arrows Left and Right, and the top-bottom direction of the vehicle is indicated by arrows Up and Down.

[0036] The vehicle underbody structure 100 includes a floor panel 102 that forms the floor surface of the vehicle, and a front suspension 104. The front suspension 104 is composed of a front suspension frame 106 and a pair of suspension towers 108, 110, for example.

[0037] The front suspension frame 106 is a member located at the front of the lower side of the floor panel 102, and has a main body portion 112, a pair of forward extension portions 114, 116, and a pair of rear extension portions 118, 120. The front extension portions 114, 116 are portions that extend from the main body portion 112 toward the front of the vehicle on the outer side of the main body portion 112 in the vehicle width direction. The rear extension portions 118, 120 are portions that extend from the main body portion 112 toward the rear of the vehicle on the outer side of the main body portion 112 in the vehicle width direction.

[0038] Loads (such as centrifugal force and inertial force of the vehicle) and vibrations having a vehicle width component that are generated when the vehicle turns are transmitted to the front suspension frame 106. Therefore, the vehicle underbody structure 100 employs a configuration that efficiently disperses and releases the load and vibrations transmitted to the front suspension frame 106 when the vehicle turns, toward the rear of the vehicle, and reinforces the inside of the floor panel 102 in the vehicle width direction.

[0039] That is, the vehicle underbody structure 100 includes a pair of floor side members 122, 124. The floor side members 122, 124 have suspension fixing parts 126, 128 that are fixed to the front suspension frame 106. The floor side members 122, 124 receive loads and vibrations that are transmitted to the front suspension frame 106 via the suspension fixing parts 126, 128.

[0040] As shown in the figure, rear end portions 130, 132, for example, of rear extension portions 118, 120 located widthwise outboard of the main body portion 112 in the center of the front suspension frame 106 in the vehicle width direction are fixed to the suspension fixing portions 126, 128 of the floor side members 122, 124.

[0041] The floor side members 122, 124 further have first portions 134, 136 and second portions 138, 140. The first portions 134, 136 and the second portions 138, 140 are portions that branch off from rear ends 130, 132 of rear extension portions 118, 120 of the front suspension frame 106 fixed to the susfle fixing portions 126, 128 and extend toward the rear of the vehicle.

[0042] The first portions 134, 136 branch out from the rear ends 130, 132 of the rear extensions 118, 120 of the front suspension frame 106 toward the outside in the vehicle width direction and have an arc shape that convex outward in the vehicle width direction. The second portions 138, 140 branch out from the rear ends 130, 132 of the rear extensions 118, 120 of the front suspension frame 106 toward the inside in the vehicle width direction and have an arc shape that convex inward in the vehicle width direction. Note that the arc shape is not limited to a circular arc shape that is a part of a circle, but also includes an arc shape that is a part of an ellipse.

[0043] Therefore, in the vehicle underbody structure 100, the load and vibration received by the floor side members 122, 124 from the front suspension frame 106 through the suspension fixing parts 126, 128 can be transmitted to the first parts 134, 136 and the second parts 138, 140 that branch off from the front suspension frame 106 and extend rearward of the vehicle, and can be efficiently dispersed and released rearward of the vehicle. In addition, in the vehicle underbody structure 100, the second parts 138, 140 of the floor side members 122, 124 branch off to the inside in the vehicle width direction and extend rearward of the vehicle, so that the inside of the floor panel 102 in the vehicle width direction can be reinforced. Therefore, the floor vibration of the floor panel 102 can be suppressed and the torsional rigidity can be increased. Therefore, according to the vehicle underbody structure 100, the vibration of the front suspension frame 106 and the floor panel 102 that occurs when the vehicle turns can be suppressed, and the steering stability and NV characteristics of the vehicle can be improved.

[0044] Furthermore, in the vehicle undercarriage structure 100, the first portions 134, 136 and the second portions 138, 140 are arc-shaped. This makes it possible to prevent vibrations and loads transmitted from the front suspension frame 106 to the first portions 134, 136 and the second portions 138, 140 via the suspension fixing portions 126, 128 from concentrating locally at the first portions 134, 136 and the second portions 138, 140, thereby improving the efficiency of transmission of vibrations and loads.

[0045] The vehicle underbody structure 100 further includes a pair of side sills 142, 144 and a pair of front side members 146, 148. The side sills 142, 144 extend in the front-rear direction of the vehicle along the edge of the floor panel 102, and are disposed outward in the vehicle width direction than the first portions 134, 136 of the floor side members 122, 124. The front side members 146, 148 are positioned further forward of the side sills 142, 144 and extend in the front-rear direction of the vehicle.

[0046] The vehicle underbody structure 100 further includes a pair of torque boxes 150, 152, and a connecting member 154. The torque boxes 150, 152 connect the front side members 146, 148 to the side sills 142, 144. The connecting member 154 connects the torque boxes 150, 152 to each other.

[0047] In the floor side members 122, 124, the front end portions 156, 158 of the first portions 134, 136 connect the torque boxes 150, 152 and the connecting member 154 from below so as to straddle a joint surface 159 (see FIG. 2) between the torque boxes 150, 152 and the connecting member 154. This makes it possible to increase the connection rigidity between the torque boxes 150, 152 and the connecting member 154. In addition, vibrations and loads transmitted from the front suspension frame 106 to the first portions 134, 136 via the suspension fixing portions 126, 128 on either the left or right side can be dispersed and released from the front end portions 156, 158 of the first portions 134, 136 via the connecting member 154 to the torque boxes 150, 152 on the opposite side.

[0048] Furthermore, in the floor side members 122, 124, the front end portions 160, 162 of the second portions 138, 140 connect to the torque boxes 150, 152 from below. Therefore, in the floor side members 122, 124, the vibrations and loads transmitted to the second portions 138, 140 via the suspension fixing portions 126, 128 can be dispersed and released from the front end portions 160, 162 of the second portions 138, 140 to the torque boxes 150, 152.

[0049] Thus, in the floor side members 122, 124, the front ends 156, 158 of the first parts 134, 136 are connected to the torque boxes 150, 152 and the connecting member 154 at the suspensory fixing parts 126, 128, and the front ends 160, 162 of the second parts 138, 140 are connected to the torque boxes 150, 152. As a result, in the floor side members 122, 124, vibrations and loads transmitted to the first parts 134, 136 and the second parts 138, 140 via the suspensory fixing parts 126, 128 can be dispersed in all four directions from the suspensory fixing parts 126, 128 and released, for example, as shown by arrows A and B in FIG.

[0050] The vehicle underbody structure 100 further includes a lower cross member 164 and a pair of rear side members 166, 168. The lower cross member 164 extends in the vehicle width direction below the floor panel 102 and is disposed rearward of the second portions 138, 140 of the floor side members 122, 124, and further connects the side sills 142, 144 together. The rear side members 166, 168 extend from a rear end 170 of the vehicle toward the front of the vehicle and are connected to the lower cross member 164. A pair of suspension fixing portions 171, 173 to which swingable suspensions for rear wheels (not shown) are fixed are connected to the rear side members 166, 168.

[0051] Rear end portions 172, 174 of the first portions 134, 136 of the floor side members 122, 124 are connected to inner side surfaces 176, 178 of the side sills 142, 144 on the vehicle width direction, and to the lower cross member 164. Rear end portions 180, 182 of the second portions 138, 140 are connected to the rear end portions 172, 174 of the first portions 134, 136, and are indirectly connected to the lower cross member 164 via these rear end portions 172, 174.

[0052] In this way, the floor side members 122, 124 have their rear ends 172, 174 of the first portions 134, 136 branching off from the front suspension frame 106 connected to the highly rigid side sills 142, 144, and their rear ends 180, 182 of the second portions 138, 140 indirectly connected to the lower cross member 164.

[0053] As a result, the floor side members 122, 124 can transmit the load and vibration transmitted from the front suspension frame 106 via the suspension fixing parts 126, 128 through the first parts 134, 136 and the second parts 138, 140 to the side sills 142, 144 and the lower cross member 164, dispersing the load and vibration and dissipating it throughout the vehicle.

[0054] In addition, because the first portions 134, 136 are connected to the highly rigid side sills 142, 144, it is possible to suppress vibration of the first portions 134, 136. Furthermore, because the rear ends 180, 182 of the second portions 138, 140 of the floor side members 122, 124 are indirectly connected to the lower cross member 164, it is possible to transmit and disperse load and vibration not only to the lower cross member 164 but also to the side sills 142, 144 via the second portions 138, 140.

[0055] The vehicle underbody structure 100 further includes a center tunnel 184, a bridging portion 186, and an upper cross member 188. The center tunnel 184 extends in the vehicle front-rear direction, protruding upward at the center of the floor panel 102 in the vehicle width direction. The bridging portion 186 is disposed inside the center tunnel 184, and bridges between two side walls 190, 192 of the center tunnel 184 in the vehicle width direction. The upper cross member 188 extends in the vehicle width direction above the floor panel 102, and connects the side sills 142, 144 to each other.

[0056] The second portions 138, 140 of the floor side members 122, 124 branch off from the front suspension frame 106 and extend toward the rear of the vehicle so as to gradually approach and become adjacent to the center tunnel 184 as shown in the figure. Therefore, the floor side members 122, 124 can transmit the load and vibration transmitted from the front suspension frame 106 to the second portions 138, 140 via the suspension fixing portions 126, 128 to the center tunnel 184 and disperse them. This makes it possible to suppress floor vibration of the floor panel 102.

[0057] Furthermore, since the vibration surface of floor panel 102 can be divided in the vehicle width direction by center tunnel 184, it is possible to suppress surface vibration of floor panel 102. Note that here, second portions 138, 140 are disposed adjacent to but not in contact with center tunnel 184 as shown in the figure, but are not limited to this and may abut or be connected to center tunnel 184.

[0058] The bridging portion 186 is adjacent to the points 194, 196 of the second parts 138, 140 of the floor side members 122, 124 that are most convex toward the inside in the vehicle width direction. This allows the floor side members 122, 124 to transmit the load and vibration transmitted from the front suspension frame 106 to the second parts 138, 140 via the suspension fixing parts 126, 128 to the part of the center tunnel 184 where the bridging portion 186 is disposed and has high rigidity. In addition, by disposing the bridging portion 186 inside the center tunnel 184, the rigidity of the floor panel 102 can be increased. Therefore, floor vibration of the floor panel 102 can be suppressed.

[0059] Furthermore, in the floor side members 122, 124, the points 198, 200 of the first portions 134, 136 that are most convex toward the outside in the vehicle width direction and the points 194, 196 of the second portions 138, 140 that are most convex toward the inside in the vehicle width direction overlap the upper cross member 188 via the floor panel 102, and are joined together with the floor panel 102 to the underside of the upper cross member 188.

[0060] As a result, floor side members 122, 124 can transmit and disperse the load and vibration transmitted from front suspension frame 106 to first portions 134, 136 and second portions 138, 140 via suspension fixing portions 126, 128 to upper cross member 188. Also, because first portions 134, 136 and second portions 138, 140 of floor side members 122, 124 are connected by upper cross member 188, the rigidity of each of these members can be increased and vibration of each of these members can be suppressed.

[0061] Fig. 2 is a diagram showing a state where a part of the vehicle underbody structure 100 in Fig. 1 is viewed from diagonally below. The figure shows the configuration of the suspension fixing portion 126 of the floor side member 122 and its surroundings. Although not shown, the suspension fixing portion 128 of the floor side member 124 and its surroundings have the same configuration.

[0062] In the floor side member 122, an end face 204 of the second portion 138 is connected to the side surface 202 of the first portion 134. Furthermore, the second portion 138 is formed with a protruding portion 208 that protrudes from its lower surface 206 toward the first portion 134. The protruding portion 208 of the second portion 138 is connected to and overlaps a lower surface 210 of the first portion 134. Furthermore, the rear end portion 130 of the rear extension portion 118 of the front suspension frame 106 is connected to and overlaps the protruding portion 208 of the second portion 138 of the floor side member 122, as shown in the figure.

[0063] As a result, in the vehicle undercarriage structure 100, the underside 210 of the first portion 134 of the floor side member 122, the protruding portion 208 of the second portion 138, and the rear end portion 130 of the rear extension portion 118 of the front suspension frame 106 can be connected at the suspension fixing portion 126, for example, by overlapping and joining them or by fastening them together with a bolt 212 as shown in the figure.

[0064] This increases the connection rigidity of the front suspension frame 106 and the first portion 134 and second portion 138 of the floor side member 122. Also, because the underside 210 of the first portion 134 of the floor side member 122, the protruding portion 208 of the second portion 138, and the rear end portion 130 of the rear extension portion 118 of the front suspension frame 106 are connected in a vertically overlapping manner, it becomes easier to transmit load and vibration from the front suspension frame 106 to the first portion 134 and second portion 138 of the floor side member 122 via the suspension fixing portion 126.

[0065] The vehicle underbody structure 100 further includes reinforcing members 214, 216 shown by dotted lines in the figure. The reinforcing members 214, 216 are disposed inside the first portion 134 of the floor side member 122 at positions that vertically overlap the suspension fixing portion 126. The reinforcing members 214, 216 also function as walls inside the first portion 134, and form a substantially rectangular closed cross-sectional structure together with the side surface 202, the lower surface 210 of the first portion 134, and the lower surface 218 of the floor panel 102. In this way, in the floor side member 122, the reinforcing members 214, 216 can form a closed cross-sectional structure inside the first portion 134, thereby increasing the rigidity around the suspension fixing portion 126 and suppressing vibration.

[0066] Fig. 3 is a diagram showing another part of the vehicle underbody structure 100 shown in Fig. 1 as viewed from diagonally below. The figure shows the configuration of the suspension fixing portion 128 of the floor side member 124 and its surroundings. Although not shown, the suspension fixing portion 126 of the floor side member 122 and its surroundings have the same configuration.

[0067] As shown in the figure, in the floor side member 124, the lower surface 220 of the first portion 136 and the lower surface 222 of the second portion 140 are inclined so as to become lower from the rear end portion 174 of the first portion 136 and the rear end portion 182 of the second portion 140 toward the rear end portion 132 of the rear extension portion 120 of the front suspension frame 106. Note that dotted lines C and D in the figure indicate the heights of the rear end portion 174 of the first portion 136 and the rear end portion 182 of the second portion 140, respectively.

[0068] In this way, in the floor side member 124, the lower surface 220 of the first portion 136 and the lower surface 222 of the second portion 140 are inclined so as to become lower from the rear end portions 174, 182 toward the front suspension frame 106. Therefore, in the vehicle undercarriage structure 100, the suspensory fixing portion 128 can be set at the lowest position of the lower surface 220 of the first portion 136 and the lower surface 222 of the second portion 140, and the front suspension frame 106 can be fixed to this suspensory fixing portion 128. In addition, the load and vibration transmitted from the front suspension frame 106 to the first portion 136 and the second portion 140 of the floor side member 124 via the suspensory fixing portion 128 can be efficiently transmitted toward the rear end portion 174 of the lower surface 220 of the first portion 136 and the rear end portion 182 of the lower surface 222 of the second portion 140.

[0069] Here, the lower surface 220 of the first portion 136 and the lower surface 222 of the second portion 140 of the floor side member 124 are inclined so as to become lower from the rear end portion 174 of the first portion 136 and the rear end portion 182 of the second portion 140 toward the front suspension frame 106, but this is not limited thereto, and the lower surface 220 may be inclined so as to become higher toward the front suspension frame 106. In this way, the suspensory fixing portion 128 can be set at the highest position of the lower surface 220 of the first portion 136 and the lower surface 222 of the second portion 140, and the front suspension frame 106 can be fixed to the suspensory fixing portion 128.

[0070] Fig. 4 is a diagram showing a modified example of the vehicle underbody structure 100 of Fig. 1. The modified vehicle underbody structure 100A differs from the above-described vehicle underbody structure 100 in that it includes floor side members 122A, 124A and a lower cross member 164A.

[0071] The floor side members 122A, 124A have first portions 134A, 136A and second portions 138A, 140A. The first portions 134A, 136A and the second portions 138A, 140A are portions that branch off from rear ends 130, 132 of rear extensions 118, 120 of the front suspension frame 106 fixed to the susfle fixing portions 126A, 128A and extend toward the rear of the vehicle.

[0072] The first portions 134A, 136A are integrated with the rear side members 166, 168 shown in Fig. 1. As shown in Fig. 4, the first portions 134A, 136A branch out from the front suspension frame 106 to the outside in the vehicle width direction, form an arc shape that protrudes outward in the vehicle width direction, and further extend toward the rear of the vehicle along the side sills 142, 144 on the inside in the vehicle width direction of the side sills 142, 144. Note that portions 166A, 168A corresponding to parts of the rear side members 166, 168 are connected to the first portions 134A, 136A and the lower cross member 164A as shown in Fig. 4.

[0073] Lower cross member 164A extends in the vehicle width direction and connects first portions 134A, 136A of floor side members 122A, 124A together in place of side sills 142, 144. Second portions 138A, 140A branch off from front suspension frame 106 toward the inside in the vehicle width direction, forming arc shapes that convex toward the inside in the vehicle width direction, and are further directly connected at rear end portions 180A, 182A to first portions 134A, 136A and lower cross member 164A.

[0074] Therefore, the load and vibration transmitted from the front suspension frame 106 to the second portions 138A and 140A of the floor side members 122A and 124A via the suspension fixing portions 126A and 128A are transmitted to the rear ends of the second portions 138A and 140A. Department 180A, 182A, the force can be transmitted and dispersed to the first portions 134A, 136A and the lower cross member 164A.

[0075] Furthermore, in the vehicle understructure 100A, the load and vibration transmitted to the first portions 134A, 136A of the floor side members 122A, 124A can be transmitted to the side sills 142, 144 via the first portions 134A, 136A, and further to the rear of the vehicle. In this manner, in the vehicle understructure 100A, the load and vibration received from the front suspension frame 106 can be transmitted to the first portions 134A, 136A and the second portions 138A, 140A branching off from the front suspension frame 106 and extending toward the rear of the vehicle, and efficiently dispersed and released to the rear of the vehicle.

[0076] In addition, in the vehicle underbody structure 100A, the second portions 138A, 140A of the floor side members 122A, 124A branch out toward the inside in the vehicle width direction and extend toward the rear of the vehicle, so that the inside of the floor panel 102 in the vehicle width direction can be reinforced. This makes it possible to suppress floor vibration of the floor panel 102 and increase torsional rigidity. Therefore, according to the vehicle underbody structure 100A, it is possible to suppress vibration of the front suspension frame 106 and the floor panel 102 that occurs when the vehicle turns, and improve the steering stability and NV characteristics of the vehicle.

[0077] Fig. 5 is a diagram showing another modified example of the vehicle underbody structure 100 of Fig. 1. The modified vehicle underbody structure 100B differs from the above-described vehicle underbody structure 100 in that it includes floor side members 122B, 124B and a lower cross member 164B.

[0078] The floor side members 122B, 124B have first portions 134B, 136B and second portions 138B, 140B. The first portions 134B, 136B and the second portions 138B, 140B are portions that branch off from the rear ends 130, 132 of the rear extensions 118, 120 of the front suspension frame 106 fixed to the sus-fle fixing portions 126B, 128B and extend toward the rear of the vehicle.

[0079] The first portions 134B, 136B are integrated with the rear side members 166, 168 shown in Fig. 1. As shown in the figure, the first portions 134B, 136B branch out from the front suspension frame 106 to the outside in the vehicle width direction, form an arc shape that convex outward in the vehicle width direction, and further extend toward the rear of the vehicle along the side sills 142, 144 on the inside of the side sills 142, 144 in the vehicle width direction.

[0080] The lower cross member 164B extends in the vehicle width direction and connects the first portions 134B, 136B of the floor side members 122B, 124B together in place of the side sills 142, 144. The lower cross member 164B also has both ends 224, 226. As shown in the figure, the both ends 224, 226 have a shape that expands in the vehicle front-rear direction as it moves outward in the vehicle width direction. Furthermore, the second portions 138B, 140B branch out from the front suspension frame 106 toward the inside in the vehicle width direction, have an arc shape that convex toward the inside in the vehicle width direction, and are directly connected to the both ends 224, 226 of the lower cross member 164B at their rear ends 180B, 182B.

[0081] Therefore, the load and vibration transmitted from the front suspension frame 106 to the second portions 138B and 140B of the floor side members 122B and 124B via the suspension fixing portions 126B and 128B are transmitted to the rear ends of the second portions 138B and 140B. Department The force can be transmitted from 180B, 182B to both ends 224, 226 of the lower cross member 164B and distributed to the first portions 134B, 136B and the lower cross member 164B.

[0082] Furthermore, in the vehicle understructure 100B, the load and vibration transmitted to the first portions 134B, 136B of the floor side members 122B, 124B can be transmitted to the side sills 142, 144 via the first portions 134B, 136B, and further to the rear of the vehicle. In this manner, in the vehicle understructure 100B, the load and vibration received from the front suspension frame 106 can be transmitted to the first portions 134B, 136B and the second portions 138B, 140B that branch off from the front suspension frame 106 and extend toward the rear of the vehicle, and efficiently dispersed and released to the rear of the vehicle.

[0083] Furthermore, in the vehicle underbody structure 100B, the second portions 138B, 140B of the floor side members 122B, 124B branch out toward the inside in the vehicle width direction and extend toward the rear of the vehicle, so that the inside of the floor panel 102 in the vehicle width direction can be reinforced. This makes it possible to suppress floor vibration of the floor panel 102 and increase torsional rigidity. Therefore, according to the vehicle underbody structure 100B, it is possible to suppress vibration of the front suspension frame 106 and the floor panel 102 when the vehicle is turning, etc., and improve the steering stability and NV characteristics of the vehicle.

[0084] Fig. 6 is a diagram showing yet another modified example of the vehicle underbody structure 100 of Fig. 1. The modified vehicle underbody structure 100C differs from the above-described vehicle underbody structure 100 in that it includes floor side members 122C, 124C and a lower cross member 164C.

[0085] The floor side members 122C, 124C have first portions 134C, 136C and second portions 138C, 140C, as well as center side members 228, 230. The first portions 134C, 136C, second portions 138C, 140C, and center side members 228, 230 are portions that branch off from rear ends 130, 132 of rear extension portions 118, 120 of the front suspension frame 106 fixed to the susfle fixing portions 126C, 128C and extend toward the rear of the vehicle.

[0086] The first portions 134C, 136C branch out from the front suspension frame 106 to the outside in the vehicle width direction, incline linearly, and extend rearward along the side sills 142, 144 on the inside in the vehicle width direction of the side sills 142, 144. Further, rear end portions 232, 234 of the first portions 134C, 136C are connected to the side sills 142, 144 and the lower cross member 164C.

[0087] Therefore, the load and vibration transmitted from the front suspension frame 106 to the first portions 134C and 136C of the floor side members 122C and 124C via the suspension fixing portions 126C and 128C are transmitted to the rear ends of the first portions 134C and 136C. Department 232, 234 to the side sills 142, 144 and the lower cross member 164C for dispersion.

[0088] The second portions 138C, 140C branch off from the front suspension frame 106 toward the inside in the vehicle width direction, incline linearly, and extend toward the rear of the vehicle so as to be adjacent to the center tunnel 184. Further, rear end portions 180C, 182C of the second portions 138C, 140C are connected to the lower cross member 164C.

[0089] As a result, the load and vibration transmitted from the front suspension frame 106 to the second portions 138C, 140C of the floor side members 122C, 124C via the suspension fixing portions 126C, 128C can be transmitted and dispersed from the rear end portions 180C, 182C of the second portions 138C, 140C to the lower cross member 164C.

[0090] The center side members 228, 230 branch off from the front suspension frame 106 between the first portions 134C, 136C and the second portions 138C, 140C, extend linearly rearward of the vehicle, and are further inclined linearly toward the outside in the vehicle width direction midway. In addition, the rear end portions 236, 238 of the center side members 228, 230 are connected to the lower cross member 164C.

[0091] As a result, the load and vibration transmitted from the front suspension frame 106 via the suspension fixing parts 126C, 128C to the center side members 228, 230 of the floor side members 122C, 124C can be transmitted and dispersed from the rear end parts 236, 238 of the center side members 228, 230 to the lower cross member 164C.

[0092] It should be noted that the center side members 228, 230 branch off from the front suspension frame 106 and extend linearly to the rear of the vehicle, and are inclined linearly outward in the vehicle width direction, but this is not limited to this, and the center side members may branch off from the front suspension frame 106 and extend linearly to the rear end portions 236, 238 without inclining linearly outward in the vehicle width direction.

[0093] The suspension fixing parts 126C, 128C are formed by stacking and joining the first parts 134C, 136C, the second parts 138C, 140C and the center side members 228, 230 in the vertical direction. Furthermore, the rear ends 130, 132 of the rear extension parts 118, 120 of the front suspension frame 106 are stacked from below on the suspension fixing parts 126C, 128C. Therefore, the front suspension frame 106 can be fixed to the suspension fixing parts 126C, 128C by joining the front suspension frame 106 to them or by fastening them together with bolts or the like.

[0094] In this way, in the vehicle undercarriage structure 100C, the load and vibration transmitted from the front suspension frame 106 via the suspension fixing parts 126C, 128C to the floor side members 122C, 124C are transmitted to the first parts 134C, 136C, second parts 138C, 140C and center side members 228, 230 that branch off from the front suspension frame 106 and extend toward the rear of the vehicle, and are efficiently dispersed and released toward the rear of the vehicle.

[0095] In addition, in the vehicle underbody structure 100C, the second portions 138C, 140C of the floor side members 122C, 124C branch out toward the inside in the vehicle width direction and extend toward the rear of the vehicle, so that the inside of the floor panel 102 in the vehicle width direction can be reinforced. This makes it possible to suppress floor vibration of the floor panel 102 and increase the torsional rigidity. Therefore, according to the vehicle underbody structure 100C, it is possible to suppress vibration of the front suspension frame 106 and the floor panel 102 when the vehicle is turning, etc., and improve the steering stability and NV characteristics of the vehicle.

[0096] In the vehicle underbody structure 100C, the floor side members 122C, 124C are configured to branch from the front suspension frame 106 to the first portions 134C, 136C, the second portions 138C, 140C, and the center side members 228, 230, but are not limited to this. As an example, the floor side members 122C, 124C may branch from the front suspension frame 106 to the first portions 134C, 136C and an appropriate member extending toward the rear of the vehicle, such as the center side members 228, 230, or may branch to this appropriate member and the second portions 138C, 140C.

[0097] That is, each of floor side members 122, 124, 122A, 124A, 122B, 124B, 122C, 124C of vehicle undercarriage structures 100, 100A, 100B, 100C has at least two portions that branch off from front suspension frame 106 and extend rearward of the vehicle, and one of the at least two portions may branch off from front suspension frame 106 to the outside or inside in the vehicle width direction. If this one portion branches off to the outside in the vehicle width direction, vibrations and loads can be released to the outside in the vehicle width direction, and if it branches off to the inside in the vehicle width direction, vibrations and loads can be released to the inside in the vehicle width direction and further the inside in the vehicle width direction of floor panel 102 can be reinforced.

[0098] In addition, in the above vehicle underbody structures 100, 100A, 100B, 100C, the floor side members 122, 124, 122A, 124A, 122B, 124B, 122C, 124C are disposed on the underside of the floor panel 102, but this is not limited thereto, and they may be disposed on the upper side of the floor panel 102. Furthermore, the floor side members 122, 124, 122A, 124A, 122B, 124B, 122C, 124C are each configured as a separate member, but this is not limited thereto, and they may be configured as an integrated structure.

[0099] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Industrial Applicability]

[0100] The present invention can be used in a vehicle underbody structure. [Explanation of symbols]

[0101] 100, 100A, 100B, 100C... vehicle underbody structure, 102... floor panel, 104... front suspension, 106... front suspension frame, 108, 110... suspension tower, 112... main body, 114, 116... front extension, 118, 120... rear extension, 122, 122A, 122B, 122C, 124, 124A, 124B, 124C... floor side member, 126, 126A, 126B, 126C, 128, 128A, 128B, 128C... Souffle fixing portion, 130, 132...rear end portion of rear extension portion, 134, 134A, 134B, 134C, 136, 136A, 136B, 136C...first portion, 138, 138A, 138B, 138C, 140, 140A, 140B, 140C...second portion, 142, 144...side sill, 146, 148...front side member, 150, 152...torque box, 154...connecting member, 156, 158...front end portion of first portion, 159...joint surface, 160, 162...front end portion of second portion, 164, 1 64A, 164B, 164C...lower cross member, 166, 168...rear side member, 166A, 168A part of rear side member, 170...rear end of vehicle, 171, 173...suspension fixing part, 172, 174, 232, 234...rear end of first part, 176, 178...side of side sill, 180, 180A, 180B, 180C, 182, 182A, 182B, 182C...rear end of second part, 184...center tunnel, 186...bridge part, 188...upper cross member, 19 0, 192...side wall of center tunnel, 194, 196...location of second portion, 198, 200...location of first portion, 202...side surface of first portion, 204...end surface of second portion, 206, 222...underside of second portion, 208...projection of second portion, 210, 220...underside of first portion, 212...bolt, 214, 216...reinforcing member, 218...underside of floor panel, 224, 226...both ends of lower cross member, 228, 230...center side member, 236, 238...rear end of center side member

Claims

1. A floor panel forming a floor surface of a vehicle; a suspension frame located in front of the floor panel; a floor side member fixed to the suspension frame at a position outside the center of the suspension frame in the vehicle width direction and extending toward the rear of the vehicle, The floor side member is a first portion that branches outward in a vehicle width direction from the suspension frame and has an arc shape that protrudes outward in the vehicle width direction; a second portion that branches off from the suspension frame toward the inside in the vehicle width direction and has an arc shape that protrudes toward the inside in the vehicle width direction.

2. An end face of a second portion is connected to a side face of the first portion of the floor side member, A protruding portion is formed in the second portion of the floor side member, protruding from a lower surface thereof toward the first portion and overlapping and connected to a lower surface of the first portion, 2. The vehicle underbody structure according to claim 1, wherein the lower surfaces of the first section and the second section are inclined so as to become higher or lower as they approach the suspension frame.

3. The vehicle undercarriage structure according to claim 2, characterized in that the suspension frame overlaps the protruding portion of the second portion of the floor side member, thereby overlapping and connecting the first portion, the second portion of the floor side member and the suspension frame.

4. The vehicle undercarriage further comprises: a side sill extending in a front-rear direction of the vehicle along an edge of the floor panel; a front side member located forward of the side sill; a torque box connecting the front side member and the side sill, 4. The vehicle underbody structure according to claim 1, wherein the floor side member is connected to the torque box.

5. The vehicle undercarriage further comprises: a side sill extending in a vehicle front-rear direction along an edge of the floor panel and disposed outboard in a vehicle width direction relative to a first portion of the floor side member; a lower cross member extending in a vehicle width direction below the floor panel and disposed rearward of the second portion of the floor side member; a rear side member extending from a rear end of the vehicle toward a front side of the vehicle and connected to the lower cross member, A rear end portion of the first portion is connected to a side surface of the side sill on an inner side in a vehicle width direction, 4. The vehicle underbody structure according to claim 1, wherein a rear end of the second portion is connected to the lower cross member.

6. The vehicle underbody structure further includes a center tunnel extending upwardly in a vehicle front-rear direction at a center of the floor panel in a vehicle width direction, 6. The vehicle underbody structure according to claim 1, wherein the second portion of the floor side member extends rearward from the suspension frame toward the vehicle rear so as to gradually approach and be adjacent to the center tunnel.

7. The vehicle undercarriage structure further includes a bridging portion that is disposed inside the center tunnel and bridges between two side walls of the center tunnel in a vehicle width direction, 7. The vehicle underbody structure according to claim 6, wherein the bridge portion is adjacent to a portion of the second portion of the floor side member that is most convex toward the inside in the vehicle width direction.

8. The vehicle lower structure further includes an upper cross member extending in a vehicle width direction above the floor panel, A vehicle undercarriage structure as described in any one of claims 1 to 7, characterized in that the portion of the first portion that is most convex outward in the vehicle width direction and the portion of the second portion that is most convex inward in the vehicle width direction overlap the upper cross member via the floor panel and are joined to the underside of the upper cross member together with the floor panel.

9. A floor panel that forms a floor surface of the vehicle; a suspension frame located in front of the floor panel; a floor side member fixed to the suspension frame at a position outside the center of the suspension frame in the vehicle width direction and extending toward the rear of the vehicle; a cross member disposed rearward of the suspension frame and extending in a vehicle width direction from a center of the floor panel in a vehicle width direction toward an outer side in the vehicle width direction, The floor side member is A first portion branching outward in a vehicle width direction from the suspension frame; A second portion branching from the suspension frame toward an inner side in a vehicle width direction; a third portion branching off from the suspension frame between the first portion and the second portion, extending toward the rear of the vehicle and connected to the cross member.

Images