Reducer

A reducer comprising:

• a reduction unit configured to reduce a speed of an input torque;
• and
• an output unit configured to be supplied with a preset reduction torque through the reduction unit and to transfer an output torque to the outside,
• wherein the reduction unit comprises:
• an input shaft configured to be supplied with the input torque;
• a cycloidal disc arranged on an outer circumferential surface of the input shaft in an eccentrically rotatable manner, a tooth-type protrusion being formed along a circumference of an edge of the cycloidal disc;
• a hollow housing configured to accommodate the cycloidal disc and including a plurality of inner pins arranged to be spaced a predetermined distance apart from each other along a circumference of an inner circumferential surface of the hollow housing in a manner that possibly comes into contact with the tooth-type protrusion on the cycloidal disc;
• and
• a plurality of rolling pins coupled to the cycloidal disc and having a cylindrical structure,
• wherein the output unit comprises:
• an output rotor configured to accommodate the rolling pins and to transfer the reduction torque transferred from the rolling pins to the outside;
• and
• wherein the rolling pins are eccentrically moved relatively to the output rotor,
• wherein the reducer further comprises:
• a balancing unit formed in such a manner as to face the output unit with the reduction unit in between and configured to cancel out a twisting moment of the reduction torque that occurs when the cycloidal disc is rotated,
• wherein the balancing unit comprises:
• a balancing rotor formed in such a manner as to face the output rotor and configured to accommodate the rolling pins,
• wherein the balancing rotor comprises:
• a plurality of second rolling pin accommodation grooves formed by recessing the balancing rotor by a predetermined depth in a lengthwise direction of the rolling pins in order to accommodate the rolling pins;
• and
• a plurality of second fixation pin accommodation grooves formed by recessing the balancing rotor by a predetermined depth in a lengthwise direction of the fixation pins in order to accommodate the fixation pins that each have a hollow structure,
• wherein the output rotor and the balancing rotor are coupled to each other by a plurality of fastening means which are inserted into the fixation pins, respectively, for being coupled thereto, and thus the output rotor and the balancing rotor are rotated together in conjunction with each other.