Suspension member assembly

Abstract

This ensures the rigidity of the suspension member assembly while also providing space for battery installation. [Solution] The suspension member assembly 70 comprises a suspension member 30 and a tower bar 60, the suspension member 30 comprising left and right side beams 31L, 31R, a front cross member 34, and first and second rear cross members 32, 33, the front cross member 34 having a length in the vehicle longitudinal direction shorter than the vehicle vertical direction, the tower bar 60 is provided further rear than the front cross member 34 and above the first and second rear cross members 32, 33, connects the left and right side beams 31L, 31R in the width direction, and has at least two fastening points 61L, 61R, 62L, 62R with the left and right side beams 31L, 31R.

Description

Technical Field

[0001] The present disclosure relates to the structure of a suspension member assembly attached to the rear part of a vehicle body.

Background Art

[0002] Patent Document 1 discloses a hollow suspension member connected in a square frame shape manufactured by casting using a core. When the suspension member is configured to be hollow, there may be a case where the rigidity of a portion where a large load is input from a suspension arm or the like connected to a wheel carrier is insufficient. Therefore, in the suspension member described in Patent Document 1, a reinforcing member is provided inside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a battery electric vehicle (BEV) in which a drive device for a rear wheel is mounted in a suspension member is used. In such a battery electric vehicle, it is required to increase the mounting capacity of the battery. However, in order to mount the drive device, it is necessary to ensure the rigidity of the entire suspension member. Therefore, in some cases, the front cross member has a closed cross-section structure. However, when the front cross member has such a closed cross-section structure, there is a problem that the battery mounting space is reduced by the length of the front cross member in the vehicle front-rear direction.

[0005] Therefore, an object of the present disclosure is to ensure the rigidity of the suspension member assembly and secure a battery mounting space.

Means for Solving the Problems

[0006] The suspension member assembly of this disclosure is a suspension member assembly attached to the rear of a vehicle body, comprising a suspension member and a tower bar attached to the suspension member, wherein the suspension member is integrally formed by casting and comprises left and right side beams arranged on both sides of the rear of the vehicle and extending in the longitudinal direction, a front cross member connecting the front portions of the left and right side beams in the vehicle width direction, and a rear cross member connecting the rear portions of the left and right side beams in the vehicle width direction, wherein the length of the front cross member in the vehicle longitudinal direction is shorter than the length of the vehicle vertical direction, and the tower bar is provided further rear than the front cross member and above the rear cross member, connecting the left and right side beams in the width direction and having at least two fastening points with each of the left and right side beams.

[0007] By surrounding the front and upper front portion of the suspension member with a surface using the front cross member and tower bar, the rigidity of the front portion of the suspension member can be increased. This allows the front cross member to be constructed with a T-shape, where its length in the vehicle's longitudinal direction is shorter than its length in the vehicle's vertical direction, rather than a closed section, thus shortening the length of the front cross member in the vehicle's longitudinal direction. This allows for securing battery mounting space in front of the front cross member.

[0008] In the suspension member assembly of this disclosure, the left and right side beams are provided with upper arm connection portions to which the suspension upper arm is attached in the center in the longitudinal direction of the vehicle, The tower bar may be provided in front of the upper arm connection point.

[0009] This ensures the rigidity of the suspension member forward of the upper arm connection point.

[0010] In the suspension member assembly of this disclosure, the length of the front cross member in the vehicle width direction may be shorter than the length in the vehicle longitudinal direction.

[0011] This allows for securing battery mounting space in the center of the vehicle's width.

[0012] In the suspension member assembly of this disclosure, the rear cross member may have a first rear cross member and a second rear cross member located further forward than the first rear cross member.

[0013] This increases the overall rigidity of the suspension member assembly and suppresses deformation modes that cause the entire suspension member assembly to flex.

[0014] In the suspension member assembly of this disclosure, the second rear cross member may have a lower arm mounting portion to which a suspension lower arm is attached.

[0015] This allows the load from the coil spring, which is input via the suspension lower arm, to be received by the second rear cross member.

[0016] In the suspension member assembly of this disclosure, the lower arm mounting portion may be a through hole provided in the second rear cross member that penetrates in the longitudinal direction of the vehicle.

[0017] This ensures that the load from the coil spring, which is input via the suspension lower arm, is reliably transmitted to the second rear cross member.

[0018] In the suspension member assembly of the present disclosure, the left and right side beams include an upper portion and a lower portion, and the lower portion may be curved convexly downwards so as to create a space between it and the upper portion.

[0019] As a result, the vertical height of the entire side beam increases, the longitudinal bending rigidity of the side beam improves, and the overall rigidity of the suspension member assembly can be increased.

[0020] In the suspension member assembly of the present disclosure, the upper portion may be configured in a groove shape with the outer side in the vehicle width direction being open.

[0021] Thereby, the longitudinal bending rigidity of the upper portion can be increased.

[0022] In the suspension member assembly of the present disclosure, the lower portion may be configured in a groove shape with the lower side of the vehicle being open.

[0023] Thereby, the lateral bending rigidity of the lower portion in the vehicle width direction can be increased.

[0024] In the suspension member assembly of the present disclosure, the second rear cross member may extend from the lower surfaces of the left and right side beams and have a downwardly convex U-shaped configuration.

[0025] Thereby, the torsional rigidity of the suspension member assembly can be improved.

Advantages of the Invention

[0026] The present disclosure can ensure the rigidity of the suspension member assembly and secure the battery mounting space.

Brief Description of the Drawings

[0027] [Figure 1] It is a bottom view of the rear part of a vehicle to which the suspension member assembly of the embodiment is attached. [Figure 2] It is a perspective view of the suspension member assembly of the embodiment seen from an upper obliquely rearward direction. [Figure 3] It is a perspective view of the suspension member assembly of the embodiment seen from an upper obliquely forward direction. [Figure 4]This is a perspective view of the suspension member assembly of the embodiment, seen from below and diagonally to the rear. [Figure 5] This is a plan view of the suspension member assembly of the embodiment. [Figure 6] This is a schematic cross-sectional view of the suspension member assembly of the embodiment, which is the AA section shown in Figure 5. [Figure 7] This is a schematic cross-sectional view of the suspension member assembly of the embodiment, which is the BB cross-section shown in Figure 5. [Figure 8] This is a schematic vertical cross-sectional view of the rear base of the suspension member assembly of the embodiment, which is the CC cross-section shown in Figure 5. [Figure 9] This is a schematic cross-sectional view of the suspension member assembly of the embodiment, which is the DD cross-section shown in Figure 5. [Modes for carrying out the invention]

[0028] The suspension member assembly 70 of the embodiment will be described below. First, the vehicle 100 to which the suspension member assembly 70 is attached will be described. In each figure, FR, UP, and RH indicate the front, upper, and right sides of the vehicle 100 to which the suspension member assembly 70 is attached, respectively. The opposite directions of FR, UP, and RH indicate the rear, lower, and left sides. Hereafter, when simply using the directions front / back, left / right, and up / down, unless otherwise specified, these refer to the front / back in the front-back direction, left / right in the left-right direction, and up / down in the up / down direction of the vehicle 100. Furthermore, the front / back in the front-back direction, left / right in the left-right direction, and up / down in the up / down direction of the vehicle 100 refer to the front / back in the front-back direction, left / right in the left-right direction, and up / down in the up / down direction of the suspension member assembly 70.

[0029] As shown in Figure 1, the vehicle 100 includes a vehicle body 200 and a suspension member assembly 70 attached to the rear of the vehicle body 200. The suspension member assembly 70 comprises a suspension member 30 and a tower bar 60.

[0030] As shown in Figure 1, the vehicle body 200 includes a rear unit 10, a center unit 17, and a front unit (not shown). The rear unit 10 constitutes the rear of the vehicle body 200. The center unit 17 constitutes the central part of the vehicle body 200. The front unit (not shown) constitutes the front of the vehicle body 200. The rear unit 10, the center unit 17, and the front unit are all die-cast products manufactured by integral casting. The drive unit 19 of the vehicle 100 is mounted on the front unit.

[0031] The rear unit 10 includes left and right rear side member sections 11L and 11R, left and right rear wheelhouse sections 12L and 12R, and a rear floor section 13.

[0032] The left and right rear side member sections 11L and 11R are skeletal parts located on the left and right sides of the rear unit 10 and extending in the longitudinal direction of the vehicle. The rear side member sections 11L and 11R may, for example, be configured in a groove-shaped form with the outer side in the vehicle width direction open, and may have a structure in which multiple reinforcing ribs are arranged. Coil spring seats 15L and 15R that hold the upper ends of the coil springs 22L and 22R are arranged on the left and right rear side member sections 11L and 11R. The left and right crash boxes 14L and 14R are attached to the rear ends of the left and right rear side member sections 11L and 11R. The rear bumper reinforcement 16 is attached to the rear ends of the left and right crash boxes 14L and 14R. The rear bumper reinforcement 16 is a skeletal member that connects the rear ends of the left and right crash boxes 14L and 14R in the vehicle width direction.

[0033] The left and right rear wheel well sections 12L and 12R are semicircular, arc-shaped plate-like portions that connect to the outer edges of the left and right rear side member sections 11L and 11R in the vehicle width direction. The left and right rear wheel well sections 12L and 12R house the rear wheels inside.

[0034] The rear floor section 13 is a plate member that connects the left and right rear side member sections 11L and 11R.

[0035] The center unit 17 is connected to the front of the rear unit 10 by bolts or welding. A cabin (not shown) is mounted above the center unit 17. A battery pack 18 is mounted on the center unit 17. As shown in Figure 1, the center of the battery pack 18 in the vehicle width direction protrudes rearward toward the suspension member 30. This protruding portion may house auxiliary components of the battery pack 18, such as a junction box and an ECU.

[0036] The suspension member 30 is integrally formed by casting and mounted under the rear unit 10 of the vehicle body 200. The suspension member 30 is a rectangular frame-shaped member that includes left and right side beams 31L and 31R, a rear first rear cross member 32, a second rear cross member 33, and a front cross member 34. Here, the first rear cross member 32 and the second rear cross member 33 constitute a rear cross member that connects the left and right side beams 31L and 31R in the vehicle width direction at the rear part of the suspension member 30. The front cross member 34 connects the left and right side beams 31L and 31R in the vehicle width direction at the front part of the suspension member 30.

[0037] The left and right side beams 31L and 31R are positioned on both the left and right sides of the vehicle 100 and extend in the longitudinal direction of the vehicle. At the front ends of the left and right side beams 31L and 31R, there are left and right front body mounting parts 35L and 35R which are attached to the underside of the left and right rear side member parts 11L and 11R by mounting members. At the rear ends of the left and right side beams 31L and 31R, there are rear body mounting parts 36L and 36R which are attached to the underside of the rear unit 10 by mounting members. The left and right rear ends 37L and 37R of the left and right side beams 31L and 31R extend towards the rear of the vehicle from the rear body mounting parts 36L and 36R. The left and right rear ends 37L and 37R are located further rearward than the front ends of the left and right crash boxes 14L and 14R.

[0038] As shown in Figures 2 and 3, the upper parts of the left and right side beams 31L and 31R are provided with left and right first upper arm connection parts 45L and 45R to which the left and right first suspension upper arms 23L and 23R (see Figure 1) are connected, and left and right second upper arm connection parts 46L and 46R to which the left and right second suspension upper arms 24L and 24R (see Figure 1) are connected. The left and right first upper arm connection parts 45L and 45R are located immediately behind the left and right front body mounting parts 35L and 35R. The second upper arm connection parts 46L and 46R are located in the center of the left and right side beams 31L and 31R in the vehicle's longitudinal direction. The first upper arm connection parts 45L and 45R and the second suspension upper arms 24L and 24R are each composed of two plate-like members. Furthermore, as shown in Figure 3, the upper parts of the left and right side beams 31L and 31R are provided with left and right front bases 48L and 48R and left and right rear bases 49L and 49R, to which the tower bar 60 is attached.

[0039] As shown in Figure 3, the front cross member 34 is the part that connects the left and right front body mounting parts 35L and 35R in the vehicle width direction. As shown in Figure 4, the rear first rear cross member 32 is the part that connects the left and right rear body mounting parts 36L and 36R in the vehicle width direction. The second rear cross member 33 is located in front of the first rear cross member 32 and is the part that connects the left and right side beams 31L and 31R in the vehicle width direction. As will be explained later, the second rear cross member 33 extends from the lower surface of the left and right side beams 31L and 31R and is a U-shaped part that is convex downwards. The left and right ends of the second rear cross member 33 are provided with left and right lower arm mounting parts 39L and 39R to which the suspension lower arms 21L and 21R are attached.

[0040] As shown in Figures 1 and 5, the suspension member 30 is connected to multiple arms of the left and right suspension devices 20L and 20R that suspend the left and right rear wheels. The suspension devices 20L and 20R consist of multiple arms that connect the left and right rear wheel knuckles to the suspension member 30, coil springs 22L and 22R, and left and right shock absorbers (not shown). Of these, the vehicle body side ends of the left and right suspension lower arms 21L and 21R are connected to the left and right lower arm mounting portions 39L and 39R of the second rear cross member 33. In addition, the left and right coil springs 22L and 22R are attached to the upper parts of the left and right suspension lower arms 21L and 21R. The upper ends of the left and right coil springs 22L and 22R are held by the coil spring seats 15L and 15R of the left and right rear side member portions 11L and 11R. Furthermore, as shown in Figure 5, the vehicle-side ends of the left and right first suspension upper arms 23L and 23R are connected to the first upper arm connection parts 45L and 45R. Also, the vehicle-side ends of the left and right second suspension upper arms 24L and 24R are connected to the second upper arm connection parts 46L and 46R. Note that the arms other than the left and right suspension lower arms 21L and 21R, the left and right first suspension upper arms 23L and 23R, and the left and right second suspension upper arms 24L and 24R are not shown or described.

[0041] As shown in Figures 3 and 5, the tower bar 60 is a plate-shaped member that connects the left and right side beams 31L and 31R in the vehicle width direction. Multiple reinforcing beads (not shown) are provided on the upper surface of the tower bar 60. The tower bar 60 is attached by bolts 65 to the left and right front bases 48L and 48R and the left and right rear bases 49L and 49R, which are provided on the upper part of the left and right side beams 31L and 31R. The fastening points between the front bases 48L and 48R and the left and right rear bases 49L and 49R constitute the left and right front fastening points 61L and 61R and the left and right rear fastening points 62L and 62R of the tower bar 60. As shown in Figures 3 and 5, the tower bar 60 is located behind the front cross member 34 and above the first rear cross member 32 and the second rear cross member 33.

[0042] Next, we will describe the structural details of the suspension member 30 and the tower bar 60 with reference to Figures 2 to 9. First, we will describe the structural details of the suspension member 30.

[0043] As explained earlier with reference to Figure 1, the suspension member 30 is a rectangular frame-shaped member that includes the left and right side beams 31L and 31R, the rear first rear cross member 32, the second rear cross member 33, and the front cross member 34.

[0044] As shown in Figures 2 to 5, the left side beam 31L includes an upper portion 41L and a lower portion 51L. The lower portion 51 is curved downwards in a convex shape so that there is a space between it and the upper portion 41.

[0045] The upper section 41L includes a front section 42L, a connecting section 42C, a central section 43L, a rear section 44L, and a rear end section 37L of the vehicle. The front section 42L extends from the left front body mounting section 35L diagonally upward and rearward to the rear of the first upper arm connecting section 45L. The connecting section 42C connects to the front section 42L and extends from the rear of the first upper arm connecting section 45L diagonally upward and rearward to just before the second upper arm connecting section 46L. The central section 43L connects to the rear end of the connecting section 42C and curves upward in a convex shape, with the rear end extending horizontally toward the rear of the vehicle. The rear section 44L connects to the rear end of the central section 43L and extends horizontally toward the rear of the vehicle to the rear body mounting section 36L. The left rear end of the vehicle, 37L, is the portion that extends horizontally toward the rear of the vehicle from the left rear body mounting section, 36L, as explained earlier.

[0046] As shown in Figure 6, the central section 43L is composed of a web 43A, an upper flange 43B, and a lower flange 43C, and has a groove-shaped form that is open on the outer side in the vehicle width direction (to the left of the vehicle). Similarly, the front section 42L and the rear section 44L also have a groove-shaped form that is open on the outer side in the vehicle width direction (to the left of the vehicle). Therefore, the bending rigidity of the upper sections 41L and 41R around the X0 axis is greater than the bending rigidity around the Z0 axis. Here, the X0 axis is a coordinate axis in the vehicle width direction passing through the center of the cross-section of the upper section 41L, and the Z0 axis is a coordinate axis in the vertical direction passing through the center of the cross-section of the upper section 41L. Also, as shown in Figures 2 and 3, the front section 42L and the rear section 44L are provided with plate-shaped rib plates 47 that extend in the vehicle width direction (to the left of the vehicle). A mount attachment section 58L to which the mount of the drive unit 19 is attached is provided at the rear of the central section 43L. As shown in Figures 3 and 8, the connecting portion 42C has a groove-shaped form with the upper side of the vehicle open, and, similar to the lower portion 51L which will be described later, its bending rigidity around the Z2 axis is greater than its bending rigidity around the X2 axis. Here, the Z2 axis is a coordinate axis in the vertical direction passing through the center of the cross-section of the connecting portion 42C, as shown in Figure 8, and the X2 axis is a coordinate axis in the vehicle width direction passing through the center of the cross-section of the connecting portion 42C.

[0047] As shown in Figure 4, the lower left portion 51L includes a front end 52L, a rear end 54L, and a curved portion 53L. The front end 52L is the portion that connects to the lower side of the front portion 42L of the upper portion 41L. The rear end 54L is the portion that connects to the lower side of the rear portion 44L of the upper portion 41L. The curved portion 53L is the portion that curves downwards convexly between the front end 52L and the rear end 54L. A cylindrical space 50L is open between the upper surface of the curved portion 53L and the lower surface of the central portion 43L of the upper portion 41L. As shown in Figure 6, the space 50L is the space through which the drive shaft 19A passes in the vehicle width direction.

[0048] As shown in Figures 4 and 6, the curved portion 53L of the lower part 51L is composed of a web 53A, an inner flange 53B, and an outer flange 53C, and has a groove-shaped form with the underside of the vehicle open. Therefore, the bending stiffness of the curved portion 53L is greater around the Z1 axis than around the X1 axis. Here, the Z1 axis is a coordinate axis in the vertical direction passing through the center of the cross-section of the curved portion 53L, and the X1 axis is a coordinate axis in the vehicle width direction passing through the center of the cross-section of the curved portion 53L. Similarly, the front end portion 52L and the rear end portion 54L also have a groove-shaped form with the underside of the vehicle open, and their bending stiffness is greater around the Z1 axis than around the X1 axis. The front end portion 52L, the curved portion 53L, and the rear end portion 54L are provided with a plurality of plate-shaped rib plates 55 extending in the vertical direction of the vehicle.

[0049] As shown in Figures 3, 5, and 7, the left front base 48L is located immediately behind the left front body mounting portion 35L. The left front base 48L is a portion that protrudes inward in the vehicle width direction from the inner surface in the vehicle width direction of the front portion 42L, between the two plate-shaped members that constitute the first upper arm connection portion 45L. The front base 48L is provided with a screw hole into which a bolt 65 is screwed. The left rear base 49L is located at the center of the left side beam 31L in the vehicle longitudinal direction, at the front end of the central portion 43L (the rear end of the connection portion 42C). As shown in Figures 7 and 8, the rear base 49L is a cylindrical portion located between the inner end in the vehicle width direction of the front plate-shaped member of the two plate-shaped members that constitute the second upper arm connection portion 46L, and the inner flange of the connection portion 42C. The rear base 49L is also provided with a screw hole into which a bolt 65 is screwed.

[0050] The right side beam 31R is symmetrical to the left side beam 31L and includes an upper portion 41R and a lower portion 51R. The upper portion 41R includes a front portion 42R, a connecting portion 42C, a central portion 43R, a rear portion 44R, and a vehicle rear end portion 37R, and is provided with a first upper arm connecting portion 45R, a second upper arm connecting portion 46R, a front base 48R, a rear base 49R, and a mount attachment portion 58R. The lower portion 51R also includes a front end portion 52R, a rear end portion 54R, and a curved portion 53R.

[0051] As shown in Figures 3 and 7, the front cross member 34 has a T-shape comprising a vertical plate 34A and a horizontal plate 34B. The front cross member 34 is curved such that the central part in the vehicle width direction is convex toward the rear of the vehicle. In addition, the length of the central part of the front cross member 34 in the vehicle width direction is shorter in the vehicle longitudinal direction than in the vehicle vertical direction.

[0052] As shown in Figures 3 and 9, the first rear cross member 32 is composed of a web 32A, an upper flange 32B, and a lower flange 32C, and has a groove-shaped form with the rear of the vehicle open. Therefore, the bending rigidity of the first rear cross member 32 around the Y3 axis is greater than the bending rigidity around the Z3 axis. Here, the Y3 axis is a coordinate axis in the longitudinal direction of the vehicle that passes through the center of the cross section of the first rear cross member 32, and the Z3 axis is a coordinate axis in the vertical direction that passes through the center of the cross section of the curved portion 53L. In addition, the first rear cross member 32 is provided with a rib plate 32D that extends from the web 32A toward the rear of the vehicle.

[0053] As shown in Figures 4 and 9, the second rear cross member 33 extends downward from the lower surfaces of the rear ends 54L and 54R of the left and right lower portions 51L and 51R, and is a skeletal portion that connects the left and right side beams 31L and 31R in the vehicle width direction. The second rear cross member 33 is composed of a left end 33L, a right end 33R, and a horizontal portion 33H. The left end 33L and the right end 33R are portions that extend downward from the lower surfaces of the rear ends 54L and 54R. The horizontal portion 33H is the portion that connects the left end 33L and the right end 33R in the vehicle width direction. The left end 33L, the right end 33R, and the horizontal portion 33H have a downward-convex U-shape.

[0054] The horizontal section 33H is composed of a web 33A, a front flange 33B, and a rear flange 33C, and has a groove-shaped form with the underside of the vehicle open. The horizontal section 33H is also provided with a rib plate 33D extending from the web 33A toward the underside of the vehicle. As a result, the bending rigidity of the second rear cross member 33 is greater around the Z4 axis than around the Y4 axis. Here, the Z4 axis is a vertical coordinate axis passing through the center of the cross-section of the second rear cross member 33, and the Y4 axis is a longitudinal coordinate axis passing through the center of the cross-section of the second rear cross member 33. In addition, the left and right ends of the horizontal section 33H are provided with left and right lower arm mounting sections 39L and 39R. The left and right lower arm mounting sections 39L and 39R are through holes that penetrate in the longitudinal direction of the vehicle. This allows the load from the left and right coil springs 22L and 22R to be reliably transmitted to the second rear cross member 33. Furthermore, this ensures that the second rear cross member 33 can reliably withstand the loads from the left and right coil springs 22L and 22R.

[0055] In the suspension member assembly 70 of the embodiment described above, the front portion of the suspension member 30 can be made rigid by surrounding the front and upper part of the front portion of the suspension member 30 with a surface by the front cross member 34 and the tower bar 60. As a result, the front cross member 34 can be configured as a T-shape, where the length in the vehicle longitudinal direction is shorter than the length in the vehicle vertical direction, rather than a closed cross section, thereby shortening the length of the front cross member 34 in the vehicle longitudinal direction. This makes it possible to secure battery mounting space in front of the front cross member 34.

[0056] Furthermore, the front cross member 34 is curved such that its central portion in the vehicle width direction protrudes towards the rear of the vehicle. As a result, the central portion of the battery pack 18 in the vehicle width direction, which protrudes rearward toward the suspension member 30, can be accommodated in front of the front cross member 34.

[0057] In the suspension member assembly 70 of this embodiment, the front of the tower bar 60 is fastened with bolts 65 to the left and right front bases 48L and 48R, which are located immediately behind the left and right front body mounting parts 35L and 35R. The rear of the tower bar 60 is fastened with bolts 65 to the left and right rear bases 49L and 49R, which are located in the center of the left and right side beams 31L and 31R in the longitudinal direction of the vehicle. Thus, the tower bar 60 has two fastening points on the left and right side beams 31L and 31R: front fastening points 61L and 61R and rear fastening points 62L and 62R. As a result, the plate-shaped tower bar 60 and the left and right side beams 31L and 31 are integrated to increase the rigidity of the front portion of the suspension member 30.

[0058] Furthermore, in the suspension member assembly 70 of the embodiment, the tower bar 60 is positioned forward of the vehicle beyond the second upper arm connection points 46L and 46R, which are located in the center of the left and right side beams 31L and 31R in the vehicle's longitudinal direction. As a result, the tower bar 60 can increase the rigidity of the front portion of the suspension member 30 that is forward of the second upper arm connection points 46L and 46R.

[0059] Furthermore, the suspension member 30 of the suspension member assembly 70 in the embodiment has left and right spaces 50L, 50R, and is connected to left and right side beams 31L, 31R which have a high vertical height and high longitudinal bending rigidity, and a first rear cross member 32 which has a groove-shaped structure with an open rear end and high longitudinal bending rigidity. In addition, a second rear cross member 33 which is U-shaped with a downward convex shape, with an open underside of the vehicle and high lateral bending rigidity in the vehicle's longitudinal direction is connected to the lower surface of the left and right side beams 31L, 31R. This makes it possible to increase the rigidity of the rear part of the suspension member 30.

[0060] In this way, the suspension member assembly 70 increases the rigidity of the front part of the suspension member 30 by surrounding the front and upper front portion of the suspension member 30 with a surface by the front cross member 34 and the tower bar 60, and increases the rigidity of the rear part of the suspension member assembly 70 by connecting the first rear cross member 32 and the second rear cross member 33, which have different directions of high rigidity, to the left and right side beams 31L and 31R. As a result, the overall rigidity of the suspension member assembly 70 can be increased. This makes it possible to suppress deformation modes or return deformations that cause the entire suspension member assembly 70 to deform.

[0061] Furthermore, the suspension member 30 has a groove-shaped configuration in which the upper portions 41L and 41R of the left and right side beams 31L and 31R are open on the outer side in the vehicle width direction or on the upper side of the vehicle, and the first rear cross member 32 has a groove-shaped configuration in which the rear side of the vehicle is open. In addition, the lower portions 51L and 51R of the left and right side beams 31L and 31R and the second rear cross member 33 have a groove-shaped configuration in which the lower side of the vehicle is open. Therefore, by setting the molding direction to the outer side in the vehicle width direction, the rear side of the vehicle, and the vertical direction of the vehicle, the suspension member 30 can be constructed by integral casting.

[0062] In the above description, the tower bar 60 was described as having two fastening points on the left and right side beams 31L and 31R: front fastening points 61L and 61R and rear fastening points 62L and 62R. However, it is not limited to this. For example, it may be configured to have three or more fastening points on each of the left and right side beams 31L and 31R. [Explanation of Symbols]

[0063] 10 Rear unit, 11L, 11R Rear side member section, 12L, 12R Rear wheelhouse section, 13 Rear floor section, 14L, 14R Crash box, 15L, 15R Coil spring seat, 16 Rear bumper reinforcement, 17 Center unit, 18 Battery pack, 19 Drive unit, 19A Drive shaft, 20L, 20R Suspension system, 21L, 21R Suspension lower arm, 22L, 22R Coil spring, 23L, 23R First suspension upper arm, 24L, 24R Second suspension upper arm, 30 Suspension member, 31L, 31R Side beam, 32 First rear cross member, 32A, 33A, 43A, 53A Web, 32B, 43B Upper flange, 32C, 43C Lower flange, 32D, 33D, 47, 55 Rib plate, 33 33L, 33R 2nd rear cross member, 33B Front flange, 33C Rear flange, 33H Horizontal section, 33L Left end, 33R Right end, 34 Front cross member, 34A Vertical plate, 34B Horizontal plate, 35L, 35R Front body mounting section, 36L, 36R Rear body mounting section, 37L, 37R Rear end of vehicle, 39L, 39R Lower arm mounting section, 41L, 41R Upper section, 42C Connection section, 42L, 42R Front section, 43L, 43R Center section, 44L, 44R Rear section, 45L, 45R 1st upper arm connection section, 46L, 46R 2nd upper arm connection section, 48L, 48R Front base, 49L, 49R Rear base, 50L, 50R Space, 51L, 51R Lower section, 52L, 52R Front end, 53B inner flange, 53C outer flange, 53L, 53R curved section, 54L, 54R rear end, 58L, 58R mount attachment section, 60 tower bar, 61L, 61R front fastening point, 62L, 62R rear fastening point, 65 bolt, 70 suspension member assembly, 100 vehicle, 200 body.

Claims

1. A suspension member assembly that is attached to the rear of the vehicle body, Suspension member and, The suspension member is equipped with a tower bar, The suspension member is integrally formed by casting. The left and right side beams are positioned on both sides of the rear of the vehicle and extend in the front-to-back direction, A front cross member connects the front portions of the left and right side beams in the vehicle width direction, It comprises a rear cross member connecting the rear portions of the left and right side beams in the vehicle width direction, The aforementioned front cross member has a length in the vehicle's longitudinal direction that is shorter than its length in the vehicle's vertical direction. The tower bar is provided further rearward than the front cross member and above the rear cross member, connecting the left and right side beams in the width direction, and having at least two fastening points with each of the left and right side beams. A suspension member assembly characterized by the following.

2. A suspension member assembly according to claim 1, The left and right side beams are equipped with upper arm connection points to which the suspension upper arms are connected in the center in the longitudinal direction of the vehicle. The tower bar is provided in front of the upper arm connection portion of the vehicle. A suspension member assembly characterized by the following.

3. A suspension member assembly according to claim 1, The central portion of the aforementioned front cross member in the vehicle width direction has a length in the vehicle longitudinal direction that is shorter than the length in the vehicle vertical direction. A suspension member assembly characterized by the following.

4. A suspension member assembly according to claim 1, The aforementioned rear cross member is First rear cross member and, It has a second rear cross member located further forward of the vehicle than the first rear cross member, A suspension member assembly characterized by the following.

5. A suspension member assembly according to claim 4, The second rear cross member has a lower arm mounting portion to which the suspension lower arm is attached. A suspension member assembly characterized by the following.

6. A suspension member assembly according to claim 5, The lower arm mounting portion is a through hole provided in the second rear cross member that penetrates in the vehicle's longitudinal direction. A suspension member assembly characterized by the following.

7. A suspension member assembly according to any one of claims 1 to 6, The aforementioned left and right side beams include an upper portion and a lower portion. The lower portion is curved downwards in a convex shape so that there is a space between it and the upper portion. A suspension member assembly characterized by the following.

8. A suspension member assembly according to claim 7, The aforementioned upper portion is configured with a groove-shaped form that is open on the outer side in the vehicle width direction. A suspension member assembly characterized by the following.

9. A suspension member assembly according to claim 7, The aforementioned lower portion is configured in a groove-shaped form with the underside of the vehicle open. A suspension member assembly characterized by the following.

10. A suspension member assembly according to any one of claims 4 to 6, The second rear cross member extends from the lower surfaces of the left and right side beams and has a U-shaped form that is convex downwards. A suspension member assembly characterized by the following.

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