Suspension member

Abstract

To make reduced weight and high rigidity of a suspension member compatible with each other.SOLUTION: A suspension member comprises a main body portion 1 having hollow shape, and a vehicle body mount portion 2 which directly joins the main body portion 1 to a vehicle body. The main body portion 1 has a pair of right and left side rails 11 and 12 disposed on both ends in a vehicle body width direction, extending in a longitudinal direction, and a pair of front and rear cross members 13 and 14 extending in the vehicle body width direction. The pair of right and left aide rails 11 and 12 and the pair of front and rear cross members 13 and 14 are connected by integral molding in a square frame shape in a top view, and a reinforcing member for improving rigidity of the main body portion 1 is disposed inside the main body portion 1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a suspension member of a vehicle.

Background Art

[0002] Patent Document 1 discloses a subframe (suspension member) having a pair of left and right side rails extending in the front-rear direction and a pair of front and rear cross members extending in the vehicle width direction connected in a square frame shape, and having a vehicle body attachment portion directly connected to the vehicle body without passing through a damping element such as a rubber bush.

[0003] Patent Document 2 discloses a subframe (suspension member) including a hollow main body portion and a vehicle body attachment portion for fastening the main body portion to the vehicle body, and integrally formed by casting.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a suspension member in which a pair of left and right side rails and a pair of front and rear cross members are connected in a square frame shape, when assembling the suspension member by joining the side rails and the cross members by a method such as welding, the strength of the joint portion becomes lower than that of the base material, and deformation and breakage tend to occur starting from the joint portion. In addition, in order to achieve good joining, it is necessary to ensure the quality of the base material that can be joined and the accuracy during assembly, etc. The number of processes and management items increases compared to integral molding, and the cost may increase.

[0006] Therefore, it is required to integrally form a suspension member in which a pair of left and right side rails and a pair of front and rear cross members are connected in a square frame shape by a manufacturing method such as casting. Then, by using a manufacturing method such as casting with a core, the suspension member connected in a square frame shape is formed into a hollow shape, so that a suspension member with high rigidity and good weight efficiency can be realized.

[0007] However, if the entire interior of the suspension member is completely hollowed out, the rigidity of the portion where a particularly large load is applied from the suspension arm or the like connected to the wheel carrier may be insufficient.

[0008] Therefore, an object of the present invention is to achieve both weight reduction and high rigidity of the suspension member.

Means for Solving the Problems

[0009] The suspension member according to the present invention includes a hollow main body portion and a vehicle body mount portion for directly fastening the main body portion to the vehicle body. The main body portion includes a pair of left and right side rails provided at both ends in the vehicle width direction and extending in the front-rear direction, and a pair of front and rear cross members extending in the vehicle width direction. The right side rail, the left side rail, the front cross member, and the rear cross member are integrally formed and connected in a square frame shape in a top view. The right side rail and the left side rail are each divided into two upper and lower rows, and have an annular shape in a side view with a hole penetrating in the vehicle width direction formed in the central portion. The front cross member is connected to a portion where the upper and lower two rows in front of the hole of the right side rail are connected and a portion where the upper and lower two rows in front of the hole of the left side rail are connected. The rear cross member is connected to a portion where the upper and lower two rows behind the hole of the right side rail are connected and a portion where the upper and lower two rows behind the hole of the left side rail are connected. A drive shaft extending from a differential gear disposed between the right side rail and the left side rail to both sides in the vehicle width direction is disposed so as to pass through the hole provided in the right side rail and the hole provided in the left side rail. Inside the main body portion, a reinforcing member for increasing the rigidity of the main body portion As an inner wall that partitions the boundary between the right side rail and the front cross member, an inner wall that partitions the boundary between the left side rail and the front cross member, an inner wall that partitions the boundary between the right side rail and the rear cross member, and an inner wall that partitions the boundary between the left side rail and the rear cross member, is provided.

Effects of the Invention

[0010] The present invention can achieve both weight reduction and high rigidity of the suspension member.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0012] <First Embodiment> Hereinafter, with reference to FIGS. 1 to 3, the suspension member 10 of the first embodiment will be described. The arrows FR, UP, and RH shown in each of the following figures indicate the front direction (travel direction), upward direction, and right direction of the vehicle, respectively. Also, the opposite directions of the arrows FR, UP, and RH indicate the rear direction, downward direction, and left direction of the vehicle, respectively. Hereinafter, when simply describing the directions of front and rear, left and right, and up and down, unless otherwise specified, they shall indicate the front and rear in the vehicle front-rear direction, the left and right in the vehicle left-right direction (vehicle width direction), and the up and down in the vehicle up-down direction.

[0013] FIG. 1 is a perspective view of the suspension member 10. As shown in FIG. 1, the suspension member 10 includes a hollow main body portion 1 and four vehicle body mount portions 2 for fastening the main body portion 1 to a vehicle body (not shown).

[0014] The main body portion 1 has a pair of left and right right side rails 11 and left side rails 12 provided at both ends in the vehicle width direction and extending in the front-rear direction, and a pair of front cross members 13 and rear cross members 14 extending in the vehicle width direction. Both the right side rail 11 and the left side rail 12 have a curved shape in top view such that the central portion in the front-rear direction is disposed inside the vehicle width direction rather than the front end and the rear end. The right side rail 11, the left side rail 12, the front cross member 13, and the rear cross member 14 are all of hollow shape and are connected in a square frame shape in top view by integral molding.

[0015] Right side rail 11 and the left side rail 12 are bothIt is divided into upper and lower two rows, and has an annular shape in a side view with a hole 15 penetrating in the vehicle width direction formed in the central part. The front cross member 13 is connected to the part where the upper and lower two rows in front of the hole 15 of the right side rail 11 are connected and the part where the upper and lower two rows in front of the hole 15 of the left side rail 12 are connected. The rear cross member 14 is connected to the part where the upper and lower two rows behind the hole 15 of the right side rail 11 are connected and the part where the upper and lower two rows behind the hole 15 of the left side rail 12 are connected.

[0016] The vehicle body mount part 2 is arranged at the front end and rear end of the right side rail 11 and the front end and rear end of the left side rail 12. A bolt hole 2a penetrating in the vertical direction is formed in each vehicle body mount part 2. By fastening a bolt passed through the bolt hole 2a from bottom to top to a vehicle body (not shown), the suspension member 10 is fixed to the vehicle body. The vehicle body mount part 2 is directly connected to the vehicle body without passing through a damping element such as a rubber bush.

[0017] Drive units such as a differential gear, an electric motor, and an engine are mounted on the suspension member 10. Note that the drive unit to be mounted may be only a differential gear. A cylindrical through hole 14a penetrating in the front-rear direction is formed in the rear cross member 14. The through hole 14a is used as a mount part to which the drive unit is fastened. A drive unit mount part 13a to which the drive unit is fastened is provided below the front cross member 13. The drive unit may be connected to the suspension member 10 via a damping element such as a rubber bush, or may be directly connected to the suspension member 10 without passing through a damping element such as a rubber bush.

[0018] The differential gear (not shown) is between the right side rail 11 and the left side rail 12 ofIt is disposed in between. And the drive shafts extending from the differential gear to both sides in the vehicle width direction are arranged to pass through the holes 15 provided in the right side rail 11 and the holes 15 provided in the left side rail 12. The suspension member 10 includes the right side rail 11 and the left side rail 12 having an annular shape around the axis of the drive shaft, so that a large second moment of area can be ensured against the load input from the drive shaft, and the rigidity around the tire rotation axis can be improved.

[0019] A plurality of suspension arms connected to the right wheel carrier are fastened to the right side rail 11. And a plurality of suspension arms connected to the left wheel carrier are fastened to the left side rail 12. Therefore, the load transmitted in the arm axis direction from the suspension arms to the suspension member 10 is transmitted to the vehicle body via the four vehicle body mount portions 2. The right side rail 11 and the left side rail 12 are provided with a plurality of arm fastening portions 16 to which the suspension arms are fastened. The suspension arms may be coupled to the suspension member 10 via a damping element such as a rubber bush, or may be directly coupled to the suspension member 10 without passing through a damping element such as a rubber bush.

[0020] The suspension member 10 includes fastening portions 17 for holding peripheral components such as an ECU (Electronic Control Unit), a vehicle height sensor, and a stabilizer. The fastening portions 17 are all screw holes, and these peripheral components can be fixed by fastening them with screws. These peripheral components may be coupled to the suspension member 10 via a damping element such as a rubber bush, or may be directly coupled to the suspension member 10 without passing through a damping element such as a rubber bush.

[0021] The suspension member 10 is integrally formed by casting using a core, and the hollow right side rail 11, left side rail 12, front cross member 13, and rear cross member 14 are continuously connected without joints. Therefore, compared with a suspension member in which the side rails and the cross members are joined in a square frame shape by a construction method such as welding, the suspension member 10 does not cause a decrease in rigidity at the joint, so the rigidity can be improved.

[0022] In addition, since the suspension member 10 is integrally formed by casting using a core in this way, the suspension member 10 is provided with a cope hole necessary for generating a hollow shape by casting. Therefore, in the suspension member 10, by arranging and reinforcing an annular rib in the cope hole, a local decrease in rigidity of the portion provided with the cope hole is prevented.

[0023] Further, in the suspension member 10, when a load is applied in the arm axis direction from the suspension arm to the right side rail 11 and the left side rail 12, a load that attempts to deform the front cross member 13 having a hollow elongated shape extending in the vehicle width direction by bending may be applied. Therefore, in the suspension member 10, as shown in FIG. 2, ribs 13b and 13c are provided as reinforcing members inside the front cross member 13. FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1. The rib 13b projects downward from the upper inner wall surface of the front cross member 13 and extends from the right end to the left end of the front cross member 13 along the upper inner wall surface of the front cross member 13. The rib 13c projects forward from the rear inner wall surface of the front cross member 13 and extends from the right end to the left end of the front cross member 13 along the rear inner wall surface of the front cross member 13. By providing the ribs 13b and 13c in this way, the suspension member 10 can improve the rigidity against the load that attempts to deform the front cross member 13 by bending.

[0024] In addition, in the suspension member 10, when a load is applied in the arm axis direction from the suspension arm to the right side rail 11 and the left side rail 12, a load that attempts to deform the right side rail 11 and the left side rail 12 by bending may be applied. Therefore, in the suspension member 10, an inner wall 18 and a rib 19 are provided as reinforcing members inside the right side rail 11 and the left side rail 12. FIG. 3 is a cross-sectional view taken along line B-B in FIG. 1. As shown in FIG. 3, in the right side rail 11 and the left side rail 12, the upper part and the lower part above the hole 15 are each hollow. And the inner wall 18 having a cross-shaped cross section extends in the vehicle front-rear direction inside the upper part of the right side rail 11 and the left side rail 12 above the hole 15. The rib 19 is provided so as to protrude from the inner wall surface of the lower part of the right side rail 11 and the left side rail 12 below the hole 15 and extends in the vehicle front-rear direction. By providing the inner wall 18 and the rib 19 in this way, the suspension member 10 can improve the rigidity against the load that attempts to deform the right side rail 11 and the left side rail 12 by bending.

[0025] As described above, the suspension member 10 has the hollow main body portion 1 integrally formed and seamlessly connected in a square frame shape, ribs 13b and 13c are provided inside the front cross member 13, and the inner wall 18 and the rib 19 are provided inside the right side rail 11 and the left side rail 12, so that both weight reduction and high rigidity can be achieved. And, not only does the rigidity of the suspension member 10 itself improve in this way, but also, since it is directly fastened to the vehicle body at the vehicle body mounting portion 2 without passing through damping elements such as rubber bushes, the body rigidity of the vehicle can be improved. Also, regarding the Kt value indicating the body rigidity of the vehicle, when there is no need to improve the Kt value, since the rigidity of the suspension member 10 is improved, even if the rigidity of the body skeleton portion is reduced, the same Kt value can be achieved, so that the vehicle body can be made lighter and the cost can be reduced.

[0026] <Second Embodiment> Next, with reference to FIGS. 4 to 6, the suspension member 20 of the second embodiment will be described. FIG. 4 is a perspective view of the suspension member 20. As shown in FIG. 4, the suspension member 20 includes a hollow main body portion 7 and four vehicle body mount portions 8 for fastening the main body portion 7 to a vehicle body (not shown).

[0027] The main body portion 7 has a pair of left and right side rails 21 and 22 provided at both ends in the vehicle width direction and extending in the front-rear direction, and a pair of front and rear cross members 23 and 24 provided at both ends in the front-rear direction and extending in the vehicle width direction. The right side rail 21, the left side rail 22, the front cross member 23, and the rear cross member 24 are all hollow and are integrally formed to be connected in a square frame shape in top view. The right side rail 21 and the left side rail 22 both have an annular shape in side view with a hole 25 penetrating in the vehicle width direction formed at the center.

[0028] The vehicle body mount portions 8 are arranged at the front and rear ends of the right side rail 21 and the front and rear ends of the left side rail 22. A bolt hole 8a penetrating in the vertical direction is formed in each vehicle body mount portion 8, and the suspension member 20 is fixed to the vehicle body by fastening a bolt passed through the bolt hole 8a from the bottom to the top to the vehicle body (not shown). The vehicle body mount portion 8 is directly connected to the vehicle body without passing through a damping element such as a rubber bush.

[0029] A plurality of suspension arms for connecting to the right wheel carrier are fastened to the right side rail 21. And a plurality of suspension arms for connecting to the left wheel carrier are fastened to the left side rail 22. Therefore, arm fastening portions 26 to which the suspension arms are fastened are provided on the right side rail 21 and the left side rail 22. The suspension arm may be connected to the suspension member 20 via a damping element such as a rubber bush, or may be directly connected to the suspension member 20 without passing through a damping element such as a rubber bush.

[0030] The suspension member 20 is integrally formed by casting using a core, and the hollow right side rail 21, left side rail 22, front cross member 23, and rear cross member 24 are continuously connected without joints. Therefore, compared with a suspension member in which a side rail and a cross member are joined in a square frame shape by a construction method such as welding, the suspension member 20 does not cause a decrease in rigidity at the joint, and thus the rigidity can be improved.

[0031] In the suspension member 20, since a load is applied in the arm axis direction from a suspension arm (not shown) to the right side rail 21 and the left side rail 22, a load is applied to deform it so as to twist about a straight line L1 as a rotation axis as shown by an arrow A1 in FIG. 4, or a load is applied to deform the right side rail 21 and the left side rail 22 so as to bend as shown by an arrow A2.

[0032] Therefore, in the suspension member 20, as shown in FIGS. 5 and 6, inner walls 27 and 28 are provided as reinforcing members inside the main body portion 7. FIG. 5 is a cross-sectional view taken along line C-C in FIG. 4. FIG. 6 is a cross-sectional view taken along line D-D in FIG. 4. As shown in FIG. 5, the inner wall 27 is provided so as to partition the boundary between the right side rail 21 and the front cross member 23. And the inner wall 27 is similarly provided at the boundary between the left side rail 22 and the front cross member 23. Further, as shown in FIG. 6, an inner wall 28 is provided so as to partition the boundary between the right side rail 21 and the rear cross member 24, and similarly, an inner wall 28 is provided so as to partition the boundary between the left side rail 22 and the rear cross member 24. By providing the inner walls 27 and 28 in this way, the suspension member 20 can improve the rigidity against a load that deforms the right side rail 21 and the left side rail 22 so as to twist or a load that deforms the right side rail 21 and the left side rail 22 so as to bend.

[0033] The suspension member 20 can achieve both weight reduction and high rigidity by integrally molding the hollow main body 7 into a square frame shape without joints as described above and by providing the inner walls 27 and 28. And, not only is the rigidity of the suspension member 20 itself improved in this way, but also, since it is directly fastened to the vehicle body at the vehicle body mounting portion 8 without passing through damping elements such as rubber bushes, the body rigidity of the vehicle can be improved.

[0034] <Supplement to the Embodiment> The suspension member of the present disclosure is not limited to the above-described form and can be implemented in various forms within the scope of the gist of the present disclosure. For example, the number of cross members is not limited to two, and three or more cross members may be provided.

Description of Reference Numerals

[0035] 1,7 Main body portion, 2,8 Vehicle body mounting portion, 2a,8a Bolt hole, 10,20 Suspension member, 11,21 Right side rail, 12,22 Left side rail, 13,23 Front cross member, 13a Drive unit mounting portion, 13b,13c Rib, 14,24 Rear cross member, 14a Through hole, 15,25 Hole, 16,26 Arm fastening portion, 17 Fastening portion, 18 Inner wall, 19 Rib, 27,28 Inner wall.

Claims

【Claim 1】 A main body portion having a hollow shape, and a vehicle body mounting portion for directly fastening the main body portion to the vehicle body, wherein the main body portion includes a pair of left and right side rails provided at both ends in the vehicle width direction and extending in the front-rear direction, and a pair of front and rear cross members extending in the vehicle width direction, the right side rail, the left side rail, the front cross member, and the rear cross member are integrally formed and connected in a square frame shape in top view, both the right side rail and the left side rail are divided into upper and lower two rows, and have an annular shape in side view with a hole penetrating in the vehicle width direction formed in the central portion, the front cross member is connected to a portion where the upper and lower two rows in front of the hole of the right side rail are connected and a portion where the upper and lower two rows in front of the hole of the left side rail are connected, the rear cross member is connected to a portion where the upper and lower two rows behind the hole of the right side rail are connected and a portion where the upper and lower two rows behind the hole of the left side rail are connected, a drive shaft extending from a differential gear disposed between the right side rail and the left side rail to both sides in the vehicle width direction is disposed so as to pass through the hole provided in the right side rail and the hole provided in the left side rail, inside the main body portion, as a reinforcing member for increasing the rigidity of the main body portion, an inner wall partitioning the boundary between the right side rail and the front cross member, an inner wall partitioning the boundary between the left side rail and the front cross member, an inner wall partitioning the boundary between the right side rail and the rear cross member, and an inner wall partitioning the boundary between the left side rail and the rear cross member are provided, and a suspension member is characterized in that.

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