Automobile rear suspension structure

1. An automobile rear suspension structure comprising:

a suspension including a pair of right and left trailing arms extending in a vehicle longitudinal direction and each supporting right and left rear wheels and a torsion beam extending in a vehicle width direction and coupling both trailing arms,

wherein each trailing arm includes a pair of panels having U-shaped sections and joined to each other in a state in which U-shaped openings face each other such that a sectional shape of the each trailing arm forms a closed sectional shape,

a thickness of one of the panels is greater than a thickness of the other one of the panels,

a rear wheel support unit configured to support each rear wheel is coupled to the one of the panels,

the rear wheel support unit has a hub protruding outward in the vehicle width direction from a coupling portion where the rear wheel support unit and a corresponding one of the trailing arms are coupled together, and having a shaft portion located above the trailing arm, and

each of the pair of panels has a shape such that a stiffness center in a section of a rear portion of each of the trailing arms is positioned closer to an outer top portion of a peripheral wall portion in the vehicle width direction.

2. The automobile rear suspension structure according to claim 1 , wherein

the one of the panels forms a portion of a peripheral wall portion including at least an outer top portion in the vehicle width direction in at least a section of a rear portion of the each trailing arm, and

the rear wheel support unit configured to support the each rear wheel is coupled to at least the outer top portion of the peripheral wall portion in the vehicle width direction in the section of the rear portion of the each trailing arm.

3. The automobile rear suspension structure according to claim 2 , wherein

the rear portion of the each trailing arm is wider in the vehicle width direction than a front portion of the each trailing arm.

4. The automobile rear suspension structure according to claim 2 , wherein

the pair of panels include a top panel and a bottom panel facing each other in a top-to-bottom direction,

a thickness of the top panel is greater than a thickness of the bottom panel,

at the rear portion of the each trailing arm, an outer portion of the top panel in the vehicle width direction is wider in the top-to-bottom direction than an inner portion of the top panel in the vehicle width direction, and

the rear wheel support unit coupled to the each trailing arm is coupled to the top panel of the each trailing arm.

5. The automobile rear suspension structure according to claim 4 , wherein

a closed sectional shape of the rear portion of the each trailing arm is a substantially rectangular shape,

the rear wheel support unit includes an attachment unit attached to the each rear wheel, and a bracket for supporting the attachment unit on the top panel, and

the bracket is attached over a top portion of the top panel and the outer portion of the top panel in the vehicle width direction.

6. The automobile rear suspension structure according to claim 1 , wherein

the rear portion of the each trailing arm is wider in the vehicle width direction than a front portion of the each trailing arm.

7. The automobile rear suspension structure according to claim 1 , wherein

the pair of panels include a top panel and a bottom panel facing each other in a top-to-bottom direction,

a thickness of the top panel is greater than a thickness of the bottom panel,

at the rear portion of the each trailing arm, an outer portion of the top panel in the vehicle width direction is wider in the top-to-bottom direction than an inner portion of the top panel in the vehicle width direction, and

the rear wheel support unit coupled to the each trailing arm is coupled to the top panel of the each trailing arm.

8. The automobile rear suspension structure according to claim 7 , wherein

a closed sectional shape of the rear portion of the each trailing arm is a substantially rectangular shape,

the rear wheel support unit includes an attachment unit attached to the each rear wheel, and a bracket for supporting the attachment unit on the top panel, and

the bracket is attached over a top portion of the top panel and the outer portion of the top panel in the vehicle width direction.

9. An automobile rear suspension structure comprising:

a suspension including a pair of right and left trailing arms extending in a vehicle longitudinal direction and each supporting right and left rear wheels and a torsion beam extending in a vehicle width direction and coupling both trailing arms,

wherein each trailing arm includes a pair of panels having U-shaped sections and joined to each other in a state in which U-shaped openings face each other such that a sectional shape of the each trailing arm forms a closed sectional shape,

a thickness of one of the panels is greater than a thickness of the other one of the panels, and

a rear wheel support unit configured to support each rear wheel is coupled to the one of the panels, wherein

the pair of panels include an inner panel and an outer panel facing each other in the vehicle width direction,

a thickness of the outer panel is greater than a thickness of the inner panel,

at the rear portion of the each trailing arm, a top portion of the outer panel is wider in the vehicle width direction than a bottom portion of the outer panel, and

the rear wheel support unit coupled to the each trailing arm is coupled to the outer panel of the each trailing arm.

10. The automobile rear suspension structure according to claim 9 , wherein

a closed sectional shape of the rear portion of the each trailing arm is a substantially rectangular shape, and

at the rear portion of the each trailing arm, a bottom portion of the inner panel is wider in the vehicle width direction than a top portion of the inner panel.

11. The automobile rear suspension structure according to claim 10 , wherein

the rear wheel support unit includes an attachment unit attached to the each rear wheel, and a bracket for supporting the attachment unit on the outer panel, and

the bracket is attached over the top portion of the outer panel and an outer portion of the outer panel in the vehicle width direction.

12. The automobile rear suspension structure according to claim 10 , wherein

the rear portion of the each trailing arm is wider in the vehicle width direction than a front portion of the each trailing arm.

13. The automobile rear suspension structure according to claim 9 , wherein

the rear portion of the each trailing arm is wider in the vehicle width direction than a front portion of the each trailing arm.

14. An automobile rear suspension structure comprising:

a suspension including a pair of right and left trailing arms extending in a vehicle longitudinal direction and each supporting right and left rear wheels and a torsion beam extending in a vehicle width direction and coupling both trailing arms,

wherein each trailing arm includes a pair of panels having U-shaped sections and joined to each other in a state in which U-shaped openings face each other such that a sectional shape of the each trailing arm forms a closed sectional shape,

a thickness of one of the panels is greater than a thickness of the other one of the panels, and

a rear wheel support unit configured to support each rear wheel is coupled to the one of the panels,

the one of the panels forms a portion of a peripheral wall portion including at least an outer top portion in the vehicle width direction in at least the section of a rear portion of each trailing arm,

the rear wheel support unit configured to support the each rear wheel is coupled to at least the outer top portion of the peripheral wall portion in the vehicle width direction in the section of the rear portion of the each trailing arm,

the pair of panels include an inner panel and an outer panel facing each other in the vehicle width direction,

a thickness of the outer panel is greater than a thickness of the inner panel,

at the rear portion of the each trailing arm, a top portion of the outer panel is wider in the vehicle width direction than a bottom portion of the outer panel, and

the rear wheel support unit coupled to the each trailing arm is coupled to the outer panel of the each trailing arm.

15. The automobile rear suspension structure according to claim 14 , wherein

a closed sectional shape of the rear portion of the each trailing arm is a substantially rectangular shape, and

at the rear portion of the each trailing arm, a bottom portion of the inner panel is wider in the vehicle width direction than a top portion of the inner panel.

16. The automobile rear suspension structure according to claim 15 , wherein

the rear portion of the each trailing arm is wider in the vehicle width direction than a front portion of the each trailing arm.

17. The automobile rear suspension structure according to claim 15 , wherein

the rear wheel support unit includes an attachment unit attached to the each rear wheel, and a bracket for supporting the attachment unit on the outer panel, and

the bracket is attached over the top portion of the outer panel and an outer portion of the outer panel in the vehicle width direction.

18. The automobile rear suspension structure according to claim 14 , wherein

the rear portion of the each trailing arm is wider in the vehicle width direction than a front portion of the each trailing arm.