Infinite speed ratio transmission device

An infinite speed ratio transmission device for a vehicle, comprising:

• an input shaft;
• a first toroidal unit comprising a first input disk which rotates together with the input shaft, a first output disk, and two power rollers gripped between the first input disk and the first output disk;
• a second toroidal unit comprising a second input disk which rotates together with the input shaft, a second output disk, and two power rollers gripped between the second input disk and the second output disk, the output disks of the two toroidal units being disposed coaxially adjacent to each other;
• a first sprocket disposed between the output disks, which rotates together with the output disks;
• a fixed speed ratio transmission which varies the rotation speed of the input shaft at a fixed speed ratio;
• a planetary gear set comprising a sun gear joined to a second sprocket, a planet carrier which inputs the output rotation of the fixed speed ratio transmission, and a ring gear which rotates according to the relative rotation of the sun gear and the planet carrier;
• a chain connecting the first sprocket and the second sprocket;
• a casing housing the first toroidal unit, the second toroidal unit and the planetary gear set;
• and
• an intermediate wall supporting the first sprocket free to rotate, the intermediate wall being fixed to the casing;
• wherein, the casing comprises a supporting surface which supports the intermediate wall and forms an approximate right angle to an action direction of a tension of the chain.