Abstract: A torsion beam of a coupled torsion beam axle may include an external beam having a first cross-section in which an external protrusion of a middle end portion of the external beam is formed to protrude toward upward in a longitudinal direction of the external beam, and external skirt portions are vertically extended along the longitudinal direction at both end portions of the external protrusion; and an internal beam having a second cross-section in which an internal protrusion of a middle end portion in the internal beam is inserted into the external beam to face the external protrusion of the external beam, and internal skirt portions are extended in a vertical direction at both end portions of the internal protrusion, and each external surface of the internal skirt portions and each internal surface of the external skirt portions are surface-bonded in a mutually matched state.

Abstract: A suspension system for a vehicle may include a knuckle rotatably supporting a wheel, and a lower control arm disposed along a vehicle's width direction and connecting the knuckle and a vehicle body, wherein the lower control arm includes a wheel-side end portion connected to a lower portion of the knuckle through a front lower external joint and a rear lower external joint, and two vehicle body-side end portions connected to the vehicle body through a front lower inner joint and a rear lower inner joint, the two vehicle body-side end portions including first and second vehicle body-side end portions, wherein the first vehicle body-side end portion among the two vehicle body-side end portions is connected to the vehicle body interposing a compliance control arm between the first vehicle body-side end portion and the vehicle body.

Abstract: A torsion beam of a coupled torsion beam axle may include an external beam having a first cross-section in which an external protrusion of a middle end portion of the external beam is formed to protrude toward upward in a longitudinal direction of the external beam, and external skirt portions are vertically extended along the longitudinal direction at both end portions of the external protrusion; and an internal beam having a second cross-section in which an internal protrusion of a middle end portion in the internal beam is inserted into the external beam to face the external protrusion of the external beam, and internal skirt portions are extended in a vertical direction at both end portions of the internal protrusion, and each external surface of the internal skirt portions and each internal surface of the external skirt portions are surface-bonded in a mutually matched state.

Abstract: A suspension system for a vehicle may include a knuckle rotatably supporting a wheel, and a lower control arm disposed along a vehicle's width direction and connecting the knuckle and a vehicle body, wherein the lower control arm includes a wheel-side end portion connected to a lower portion of the knuckle through a front lower external joint and a rear lower external joint, and two vehicle body-side end portions connected to the vehicle body through a front lower inner joint and a rear lower inner joint, the two vehicle body-side end portions including first and second vehicle body-side end portions, wherein the first vehicle body-side end portion among the two vehicle body-side end portions is connected to the vehicle body interposing a compliance control arm between the first vehicle body-side end portion and the vehicle body.