To provide the underfloor structure of an automobile that can enhance a cooling effect by efficiently discharging the generated heat of a heat generating part at the rear part of a vehicle body while attaining the decrease of lift of rear wheels by an undercover.
An underfloor rear part 1r of the automobile 1 is covered with the undercover 10 to reduce the lift of the rear wheels Wr, and travel air is taken into the undercover from a lead-in port 11 provided on the vehicle front side. A plurality of stepped parts 12, 13, 14, 15 extending in a vehicle cross direction are formed at the rear part of the lead-in port 11, in the longitudinal direction of the vehicle body, and air exhaust ports 12a, 13a, 14a, 15a for exhausting the travel air taken in from the lead-in port 11 are formed at both end parts in the vehicle cross direction of the stepped parts, communicating with the inside and outside of the undercover 10. The negative pressure of vortex flow formed at the stepped parts is thereby utilized to further reduce the lift of the rear wheels, and the exhaust quantity from the air exhaust ports is increased to enhance a cooling effect inside the undercover.
Yasuo Miyoshi
Iwa Saki Kokuni
Akira Kurihara
Kawamata Sumio
Masakazu Ito
Shunichi Takahashi
Toshio Takamatsu