Automobile transmission casing having reinforcement

Claim 1

A transmission casing for automobiles which comprises a casing body having a wall formed at an upper portion with an opening which is adapted to be closed by a top cover provided with gear changing motion transmitting means, said casing being adapted for receiving a main shaft, a countershaft and a reverse idle gear shaft which extend longitudinally of the casing body for carrying transmission gears, said wall of the casing body having an inner surface which is of a cross-section comprised of a plurality of outwardly curved portions connected with each other at node portions projecting inwardly with respect to the curved portions, at least one of said curved portions having a curvature which is not coaxial with one of said shafts, said wall being of a substantially uniform thickness and formed with reverse idle gear support bracket means in the vicinity of one of the node portions for supporting the reverse idle gear shaft, one of said node portions being located in the vicinity of the point of intersection between the inner surface of the wall of the casing body and a line passing through the center of said main shaft and the center of the reverse idle gear shaft.