Cycloid speed reducer

A cycloid speed reducer, comprising:

• an eccentric device comprising a rotating shaft and an eccentric assembly, wherein the rotating shaft is rotatable and the eccentric assembly is eccentrically fixed on the rotating shaft and arranged between a first end and a second end of the rotating shaft, wherein the eccentric assembly is driven by the rotating shaft to eccentrically rotate relative to an axle center of the rotating shaft;
• a first roller assembly comprising a first wheel disc and a plurality of first rollers, wherein the first rollers are disposed on the first wheel disc;
• a second roller assembly comprising a second wheel disc and a plurality of second rollers, wherein the second rollers are disposed on the second wheel disc;
• a first rotating disc assembly disposed on the eccentric assembly and rotated with the eccentric assembly, and comprising a first outer cycloid disc and a first inner cycloid disc, wherein the first outer cycloid disc and the first inner cycloid disc are arranged adjacent to each other, the first outer cycloid disc comprises at least one first outer tooth and at least one first perforation, the first inner cycloid disc comprises at least one second outer tooth and at least one second perforation, and the at least one first outer tooth and the at least one second outer tooth are in contact with the corresponding first roller of the first rollers, respectively;
• a second rotating disc assembly disposed on the eccentric assembly and rotated with the eccentric assembly, and comprising a second inner cycloid disc and a second outer cycloid disc, wherein the second inner cycloid disc and the second outer cycloid disc are arranged adjacent to each other, the second inner cycloid disc comprises at least one third outer tooth and at least one third perforation, the second outer cycloid disc comprises at least one fourth outer tooth and at least one fourth perforation, and the at least one third outer tooth and the at least one fourth outer tooth are in contact with the corresponding second roller of the second rollers, respectively, wherein the at least one first perforation, the corresponding second perforation, the corresponding third perforation and the corresponding fourth perforation are aligned with each other;
• and
• at least one connecting element penetrated through the at least one first perforation, the corresponding second perforation, the corresponding third perforation and the corresponding fourth perforation, wherein the at least one connecting element is in close contact with inner walls of the at least one first perforation, the corresponding second perforation, the corresponding third perforation and the corresponding fourth perforation,
• wherein the diameter of the second perforation and the diameter of the third perforation are equal to each other, the diameter of the first perforation and the diameter of the fourth perforation are equal to each other, and the diameter of the second perforation and the diameter of the third perforation are greater than the diameter of the first perforation and the fourth perforation.