Lower vehicle-body structure of vehicle

A lower vehicle-body structure of a vehicle, the lower vehicle-body structure comprising:

• left and right rear frames forming a closed cross section extending in a vehicle longitudinal direction;
• arm front-end supporting portions that are on lower portions of the rear frames and support left and right trailing arm front ends of a rear suspension, the arm front-end supporting portions each having a squared U-shape portion including an outer wall portion on an outer side in a vehicle width direction, an inner wall portion on an inner side in the vehicle width direction, and a front wall portion, the squared U-shape portion having a rear side being open when viewed from bottom, the inner wall portion being formed by a first gusset member, and the front wall portion being formed by a second gusset member, each of the arm front-end supporting portions including:
• an extending outer wall portion extending from the outer wall portion to a place in front of the front wall portion, the outer wall portion and the extending outer wall portion being formed by a side sill inner portion joined to each of the rear frames;
• and
• an extending inner wall portion extending from the inner wall portion to a place in front of the front wall portion, the extending inner wall portion being joined to each of the rear frames;
• and
• a first gusset reinforcement flange portion bendable outward in the vehicle width direction from the inner wall portion to the extending inner wall portion on a lower end of the first gusset member, and
• wherein the first gusset member is integrally molded so as to include the extending inner wall portion.

A lower vehicle-body structure of a vehicle, the lower vehicle-body structure comprising:

• left and right rear frames forming a closed cross section extending in a vehicle longitudinal direction;
• and
• arm front-end supporting portions that are on lower portions of the rear frames and support left and right trailing arm front ends of a rear suspension, the arm front-end supporting portions each having a squared U-shape portion including an outer wall portion on an outer side in a vehicle width direction, an inner wall portion on an inner side in the vehicle width direction, and a front wall portion, the squared U-shape portion having a rear side being open when viewed from bottom, each of the arm front-end supporting portions including:
• an extending outer wall portion extending from the outer wall portion to a place in front of the front wall portion, the outer wall portion and the extending outer wall portion being formed by a side sill inner portion joined to each of the rear frames;
• and
• an extending inner wall portion extending from the inner wall portion to a place in front of the front wall portion, the extending inner wall portion being joined to each of the rear frames,
• wherein
• the front wall portion forms a surface extending in the vehicle width direction at a place below a lower wall portion of a rear side frame of the vehicle, and
• a joining flange portion that is integrally formed in a bent manner on an upper end of the surface of the front wall portion, the joining flange portion extending to a front side of the vehicle so as to be joined to the lower portion of the rear side frame.