JP7813630B2 - Suspension mounting structure - Google Patents

Description

The present invention relates to a suspension mounting structure for a vehicle.

Patent Document 1 below discloses a vehicle suspension mounting structure. More specifically, it discloses a mounting structure for a rear suspension trailing arm to a vehicle frame. In this mounting structure, the front end of the trailing arm is attached to a suspension bracket fixed to the underside of a rear side member. The rear side member is joined to the side sill at the location of the suspension bracket. The suspension bracket fixed to the underside of the rear side member is also fixed to the side of the side sill. In other words, the front end of the trailing arm is attached to the rear side member and side sill via the suspension bracket. A reinforcing member is also attached inside the side sill at the suspension bracket mounting portion.

Japanese Patent Application Laid-Open No. 2021-11199

However, even though the above-mentioned reinforcing members have been installed, there is a demand for further improvement in the support rigidity of the trailing arm, i.e., the attachment point of the suspension arm to the vehicle body.

The object of the present invention is to provide a suspension mounting structure that can improve the support rigidity of the mounting portion of the suspension arm to the vehicle body.

The suspension mounting structure of the present invention comprises a side sill and a rear side member that overlaps at least a portion of the side sill in the longitudinal direction of the vehicle. The suspension mounting structure also comprises a battery protection member that is located to the side of the battery that drives the vehicle and overlaps both the side sill and the rear side member in the longitudinal direction of the vehicle. A suspension bracket, which serves as the vehicle body mounting portion of the rear suspension arm, is fixed to the underside of the rear side member and is also fixed to the side sill and battery protection member.

The suspension mounting structure of the present invention can improve the support rigidity of the mounting portion of the suspension arm to the vehicle body.

1 is a perspective view of a rear portion of a vehicle provided with suspension mounting structures according to an embodiment on the left and right sides, as viewed from below. FIG. 10 is a bottom view of the mounting structure on the left side. FIG. 2 is a perspective view of the right-side mounting structure as viewed from below and in front. FIG. 4 is a perspective view of the right-side mounting structure as viewed from below and behind. FIG. 10 is a cross-sectional view of a vertical section of the right-side mounting structure at the suspension arm vehicle body mounting point, as viewed from the front. FIG. 4 is a left side view of the mounting structure on the left side.

The suspension mounting structure according to the embodiment will be described with reference to the drawings.

The suspension mounting structure according to this embodiment is shown in Figures 1 to 6. As shown in Figure 1, the suspension mounting structure according to this embodiment is a mounting structure for a rear suspension arm 2 of a rear suspension 1 to a vehicle body. The rear suspension 1 according to this embodiment is a torsion beam axle (TBA) type suspension, in which a trailing arm 2 serving as a rear suspension arm 2 extends forward. The front end of the trailing arm 2 is attached to the vehicle body via a suspension bracket 3 (hereinafter simply referred to as bracket 3).

More specifically, the front end of the trailing arm 2 is attached via bracket 3 to the side sill 4 and rear side member 5, which are structurally important to the vehicle body, as well as to a battery protection member 6. The vehicle in this embodiment is a battery electric vehicle (BEV) that does not have an internal combustion engine (ICE), and a battery 7 for driving the vehicle is mounted at the bottom of the body, covering almost the entire passenger compartment. The battery 7 is attached to the battery protection member 6 via multiple battery brackets, but the battery brackets are not shown in the figure.

As shown in Figure 1, the mounting structure for this trailing arm 2 to the vehicle body is provided symmetrically on the right and left sides of the vehicle body. The following explanation will be made with reference to Figures 2 to 6, with Figures 2 and 6 showing the mounting structure on the left side and Figures 3 to 5 showing the mounting structure on the right side. Figure 5 is a view of the right-side bracket 3 cut at a vertical cross section that includes the mounting center point of the trailing arm 2, viewed from the front to the rear.

The side sill 4 extends linearly in the longitudinal direction of the vehicle on the side of the floor of the vehicle body. As shown in Figure 1, the rear end of the side sill 4 reaches the leading edge of the rear wheel arch. Although not shown in the figure, the front end of the side sill 4 also reaches the trailing edge of the front wheel arch. A B-pillar extends from the center of the side sill 4 toward the roof panel. As shown in Figure 5, the side sill 4 forms a closed cross section by joining an outer panel and an inner panel, each of which has a hat-shaped cross section, at their flanges. Reinforcing plates are also attached to the inside of the outer panel and inner panel.

The rear side member 5 is positioned inward in the vehicle width direction relative to the side sill 4 and extends in the vehicle longitudinal direction. In this embodiment, the front end of the rear side member 5 abuts and is connected to a vertical wall 8a (see Figure 3) that is part of the floor panel 8. As shown in Figures 1 and 5, the rear end of the rear side member 5 reaches the rear panel. As shown in Figure 5, the rear side member 5 forms a closed cross section by joining the flange of a member having an inverted hat-shaped cross section to the floor panel 8. As shown in Figure 2, the outer side of the rear side member 5 is also joined to the inner side of the side sill 4 at the overlapping portion with the side sill 4.

The battery protection member 6 extends in the fore-and-aft direction of the vehicle, outward of the battery 7 in the vehicle width direction and inward of the rear side member 5 in the vehicle width direction. That is, the battery protection member 6 extends in the fore-and-aft direction to the side of the battery 7, thereby protecting the battery 7 primarily from the side. As shown in FIG. 1, the rearmost portion of the battery protection member 6 curves upward and inward, wrapping around above the battery 7, and its rear end reaches the rear panel. Also, although not shown, the front end of the battery protection member 6 is joined to the lower rear end of the front side member. As shown in FIG. 5, the battery protection member 6 forms a closed cross section by joining the upper plate 6a to the flange of a member having an inverted hat-shaped cross section. However, in the portion forward of the above-mentioned vertical wall 8a and the portion wrapping around above the battery 7, the flange of the member having the inverted hat-shaped cross section is joined directly to the floor panel 8, not to the upper plate 6a.

The bracket 3 is formed by pressing steel plate, similar to the side sill 4, rear side member 5, and battery protection member 6 described above. In this embodiment, the bracket 3 is formed by joining five pressed members together by spot welding. Hereinafter, these five members will be referred to as the first member 3a to the fifth member 3e.

As shown in Figures 2 to 5, the first member 3a is welded to the underside of the rear side member 5 and the inner side surface of the side sill 4. The first member 3a is also welded to the second member 3b and the third member 3c, which will be described later. As shown in Figure 2, the first member 3a has a crank shape when viewed from the bottom, and a flange formed at its outer end (upper end in Figure 2) is welded to the inner side surface of the side sill 4. A flange formed at the inner end (lower end in Figure 2) of the first member 3a is welded to the second member 3b. The center of the crank shape of the first member 3a is formed as a vertical plate parallel to the fore-and-aft direction of the vehicle, and a mounting hole 30 (see Figures 3 and 4) is formed in this center for mounting the bushing portion 2a at the front end of the trailing arm 2.

A flange is formed on the upper edge of this central portion (the portion shown in cross section in Figure 5), and this flange is welded to the underside of the rear side member 5. A flange is also formed on the upper edge of the connection between the central portion and the outer end (see Figures 2 and 3), and this flange is also welded to the underside of the rear side member 5. The lower edge of the connection between the central portion and the inner end (the portion shown by the dotted line in Figure 5) is welded to the third member 3c (shown by the two-dot chain line in Figure 5), which will be described later.

The second member 3b is a member that faces the first member 3a and holds the bushing portion 2a of the trailing arm 2. As shown in Figures 4 and 5, the upper part of the second member 3b is welded to the inner side surface of the rear side member 5. As shown in Figures 2 to 4, a flange is formed at the front of the second member 3b, and this flange is also welded to the connection between the rear side member 5 and the vertical wall 8a. The second member 3b also has an attachment hole 30 (see Figure 3) for attaching the bushing portion 2a.

As shown in Figures 2 and 4, the third member 3c is welded at its rear edge to the second member 3b described above, and is welded near its front end to the underside of the rear side member 5 and the floor panel 8 at the connection between the rear side member 5 and the vertical wall 8a. As shown in Figure 2, a flange is formed on the inner edge of the third member 3c, and this flange is welded to the second member 3b described above. As shown in Figures 2 and 4, a flange is also formed on the outer edge of the third member 3c, and this flange is welded to the inner side surface of the side sill 4. The third member 3c is not shown in Figure 3. Because the third member 3c is located in front of the cross section in Figure 5, its position is indicated by a two-dot chain line.

The second member 3b is fixed to the battery protection member 6 by the fourth member 3d and the fifth member 3e. As shown in Figure 3, the fourth member 3d is a short angle member. A flange is formed on the outer edge of the fourth member 3d, and this flange is welded to the second member 3b described above. The flange of the fourth member 3d that is welded to the second member 3b also has an attachment hole 30 (see Figure 3) for attaching the bushing portion 2a of the trailing arm 2. Therefore, the attachment portion of the bushing portion 2a of the bracket 3 is reinforced by the double layer of the second member 3b and the fourth member 3d.

As shown in Figure 3, the fifth member 3e is also a short angle member. The outer end of the fifth member 3e is welded to the inner end of the fourth member 3d. A flange is formed on the inner edge of the fifth member 3e, and this flange is welded to the underside and side of the battery protection member 6.

Next, we will explain the positional overlapping relationship between the bracket 3 and the side sill 4, rear side member 5, and battery protection member 6, which extend in the fore-and-aft direction of the vehicle. These members satisfy the following (1) to (3): (1) At least a portion of the rear side member 5 overlaps with the side sill 4 in the fore-and-aft direction of the vehicle in a bottom view. (2) The battery protection member 6 overlaps with both the side sill 4 and the rear side member 5 in the fore-and-aft direction of the vehicle in at least a portion of the overlapping area between the side sill 4 and the rear side member 5 in a bottom view. (3) The entire bracket 3 overlaps with the battery 7 in the fore-and-aft direction of the vehicle in a bottom view.

Note that "overlapping in the vehicle longitudinal direction in bottom view" means that there is a range of overlap in the vehicle longitudinal direction, and it is not necessary that they also overlap within that overlapping range in side view. In other words, "overlapping in the vehicle longitudinal direction" does not require overlap in the vehicle vertical direction. However, in this embodiment, at the position where the bracket 3 is provided, the side sill 4, rear side member 5, battery protection member 6, and battery 7 also at least partially overlap each other in the vehicle vertical direction in side view.

The above items (1) to (3) will be explained with reference to the bottom view of FIG. 2 and the side view of FIG. 6. As shown in FIG. 6, item (1) above means that there is an overlapping area between the extension range C of the side sill 4 and the extension range B of the rear side member. Similarly, item (2) above means that there is an overlapping area between the extension range C of the side sill 4 and the extension range B of the rear side member, and the extension range E of the battery protection member 6. In this embodiment, the entire overlapping area between extension range C and extension range B is included in extension range E.

Because bracket 3 is joined to all of side sill 4, rear side member 5, and battery protection member 6, it is positioned within the overlapping range of extension ranges B, C, and E. In other words, range A of bracket 3 in the vehicle's fore-and-aft direction is included within the overlapping range of extension ranges B, C, and E. Finally, the above (3) means that range A of bracket 3 is included within extension range D of battery 7.

With the mounting structure described above, the bracket 3, which is made up of the first member 3a through the fifth member 3e, connects the side sill 4, rear side member 5, and battery protection member 6, which provide structural strength and rigidity to the vehicle body. As a result, the strength and rigidity of the vehicle body are improved in the area where the bracket 3 is installed.

Because the bracket 3 also serves as the vehicle body mounting point for the trailing arm 2, the suspension mounting structure configured as described above also improves the support rigidity of the rear suspension 1. This allows the rear suspension 1 to function more reliably, improving handling stability, vehicle dynamics, and ride comfort.

As mentioned above, the bracket 3 is joined to the side sill 4, rear side member 5, and battery protection member 6, which provide structural strength and rigidity to the vehicle body. However, these members have closed cross sections. Therefore, it would be difficult to spot-weld the bracket 3 after the hat-shaped components that make up these components have been assembled into the vehicle body. Therefore, the bracket 3 is divided into the first member 3a through the fifth member 3e, and each component is spot-welded to the hat-shaped component in advance. The hat-shaped components are then assembled into the vehicle body to complete the side sill 4, rear side member 5, and battery protection member 6. The first member 3a through the fifth member 3e are then spot-welded together to complete the bracket 3. In other words, unless the bracket 3 is constructed by dividing it into the first member 3a through the fifth member 3e, it would be difficult to assemble the side sill 4, rear side member 5, and battery protection member 6 into the vehicle body and spot-weld the bracket 3 to these components.

In this embodiment, a jack-up point 9 is located adjacent to the bracket 3 on the side sill 4. The vehicle in this embodiment is a BEV that runs on power from a battery 7, which is large and heavy. BEVs tend to be heavier than internal combustion engine vehicles (ICEVs). For this reason, the jack-up point 9 requires greater strength. As described above, the portion where the bracket 3 is located is where the side sill 4, rear side member 5, and battery protection member 6, which provide structural strength and rigidity to the vehicle body, are gathered, and these components are joined to each other by the bracket 3. In other words, the location where the bracket 3 is located has high strength and is the optimal location for the jack-up point 9.

The suspension mounting structure according to this embodiment includes a side sill 4, a rear side member 5, and a battery protection member 6. The side sill 4 extends in the longitudinal direction of the vehicle on the side of the floor of the vehicle body. The rear side member 5 extends in the longitudinal direction of the vehicle, inward in the vehicle width direction from the side sill 4, and at least a portion of the rear side member 5 overlaps with the side sill 4 in the longitudinal direction in a bottom view (see (1) above). The battery protection member 6 extends in the longitudinal direction of the vehicle, outward in the vehicle width direction from the vehicle drive battery 7 disposed on the floor, and inward in the vehicle width direction from the rear side member 5. Furthermore, the battery protection member 6 overlaps with both the side sill 4 and the rear side member 5 in the longitudinal direction of the vehicle, at least a portion of the overlapping area between the side sill 4 and the rear side member 5 in a bottom view (see (2) above).

Furthermore, the suspension bracket 3 that attaches the rear suspension arm 2 to the vehicle body is fixed to the underside of the rear side member 5, as well as to the side sill 4 and battery protection member 6. As a result, the bracket 3 connects the side sill 4, rear side member 5, and battery protection member 6, which provide the structural strength and rigidity of the vehicle body, to one another, improving the strength and rigidity of the vehicle body in the area where the bracket 3 is installed. Because the bracket 3 is also the vehicle body attachment point for the rear suspension arm 2, it also improves the support rigidity of the rear suspension 1. As a result, the rear suspension 1 can function more reliably, resulting in improved handling stability, vehicle dynamics, and ride comfort.

Furthermore, with the suspension mounting structure according to this embodiment, the entire suspension bracket 3 overlaps with the battery 7 in the fore-and-aft direction of the vehicle when viewed from the bottom (see (3) above). As described above, the strength and rigidity of the vehicle body are improved in the area where the suspension bracket 3 is provided. This also applies to lateral loads on the vehicle body. Therefore, it is possible to effectively resist side impact loads input to the area where the suspension bracket 3 is provided, and the above mounting structure effectively protects the battery 7 from side impact loads.

Furthermore, with the suspension mounting structure of this embodiment, a jack-up point 9 is set at a position adjacent to the suspension bracket 3 on the side sill 4. Although the vehicle weight increases due to the battery 7 used to drive the vehicle, by providing the jack-up point 9 adjacent to the portion of the suspension bracket 3 where the strength and rigidity of the vehicle body are improved, the jack-up point 9 can effectively support the vehicle weight.

The suspension mounting structure of the present invention is not limited to the above embodiment. For example, in the above embodiment, as described above, the bracket 3, side sill 4, rear side member 5, battery protection member 6, and battery 7 at least partially overlap one another in the vehicle vertical direction in a side view. However, these components do not necessarily have to overlap one another in the vehicle vertical direction. Also, in the above embodiment, the battery protection member 6 extends to the rear panel to protect the battery 7 from a rear-end collision. However, the battery protection member 6 only needs to extend in the fore-and-aft direction of the vehicle at least to the side of the battery 7, and does not have to extend to the rear panel.

1. Rear suspension 2. Trailing arm (rear suspension arm)
3 Suspension bracket 4 Side sill 5 Rear side member 6 Battery protection member 7 (for driving the vehicle) Battery 9 Jack-up point

Claims (4)

A suspension mounting structure,
a side sill extending in the front-rear direction of the vehicle on a side of a floor portion of the vehicle body;
a rear side member extending in a vehicle longitudinal direction inward of the side sill in a vehicle width direction and at least a portion of which overlaps with the side sill in the vehicle longitudinal direction in a bottom view;
a battery protection member that extends in the vehicle longitudinal direction outward in the vehicle width direction with respect to a battery for driving the vehicle that is disposed on the floor portion and inward in the vehicle width direction with respect to the rear side member, and that overlaps with both the side sill and the rear side member in the vehicle longitudinal direction in at least a portion of an overlapping area between the side sill and the rear side member in a bottom view;
and a suspension bracket that attaches the rear suspension arm to the vehicle body.
a suspension mounting structure, wherein the suspension bracket is fixed to the lower surface of the rear side member and is also fixed to the side sill and the battery protection member. The suspension mounting structure of claim 1, wherein the entire suspension bracket overlaps with the battery in the vehicle fore-and-aft direction when viewed from the bottom. The suspension mounting structure of claim 2, wherein a jack-up point is set at a position adjacent to the suspension bracket on the side sill. 2. The suspension mounting structure according to claim 1, wherein the battery protection member extends to a rear end of the vehicle in the vehicle longitudinal direction.