Patent ID: 8820819

Claim:
A vehicle floor frame structure comprising: a floor panel provided in a lower portion of a vehicle body and having a main floor panel and a rear floor panel; and side members provided at both sides of the floor panel in a vehicle body width direction, and each having a floor side member and a rear side member which extend in a vehicle body front-and-rear direction, the floor side member being provided on the main floor panel, the rear side member being provided on the rear floor panel, the floor side members are disposed on the main floor panel away from each other in a vehicle body width direction across a floor tunnel, wherein a reinforcement extending in the vehicle body front-and-rear direction is disposed above each of the floor side members in a vehicle body vertical direction with the main floor panel interposed therebetween in a stacked manner, an upper surface of the reinforcement is formed to become higher toward a rear of the vehicle body, a front portion and lower portions of longitudinal direction side surfaces of the reinforcement are joined to an upper surface of the main floor panel, and a rear end of the reinforcement is joined to a vertical wall formed in a front portion of the rear floor panel, whereby a first closed section space enclosed by the main floor panel, the front portion of the rear floor panel, and the reinforcement is formed in a side view, the first closed section space is formed in a triangle shape in a side view, and a lower surface of a rear end of the floor side member is formed to become gradually higher toward the main floor panel, and an upper surface of the reinforcement and the lower surface at the rear end of the floor side member are inclined at almost the same angles and are formed to have a monotonous cross-sectional shape in a side view, wherein a rear-floor front cross member extending in the vehicle body width direction is provided behind the front portion of the rear floor panel in the vehicle body front-and-rear direction, the rear-floor front cross member is joined to a lower surface of the rear floor panel to form a second closed section space in a side view, the second closed section space enclosed by the rear floor panel and the rear-floor front cross member, and the second closed section space is disposed adjacent to the first closed section space, wherein the first closed section space and the second closed section space are formed to have cross-sectional shapes which change continuously in the vehicle body front-and-rear and vertical directions, and wherein the second closed section space is disposed in the rear side and in the upper side of the vehicle body with respect to the first closed section space.