Continuously variable transmission drive system for electric vehicles with improved driving performance and energy efficiency

A continuously variable transmission drive system for an electric vehicle which is installed in a chassis (100) having wheels (110), (120) at the front and rear and supplies rotational driving force to the wheels by power supplied from a battery, comprising:

• a housing (210) fixed to the chassis (100);
• a first motor (220) installed on one side of the housing (210) and supplying rotational driving force;
• a second motor (230) installed on the other side of the housing (210) and supplying rotational driving force;
• a first gear assembly (240) including a sun gear (241) built into the housing (210) and having a main input shaft (241a) connected to the rotational shaft of the first motor (220), an inner ring gear (242) arranged to surround the sun gear (241) in a circumferential direction, a plurality of planetary gears (243) arranged between the sun gear (241) and the inner ring gear (242), and a carrier (244) having an output shaft (244a) protruding outward from the housing (210) on the opposite side of the main input shaft (241a) and connected to the rotational shafts of the plurality of planetary gears (243);
• and a second gear assembly (250) including a sub-drive gear (251) built into the housing (210) and having a sub-input shaft (251a) connected to the rotational axis of the second motor (230), an outer ring gear (252) forming one body with the outer side of the inner ring gear (242), and an idler gear (253) arranged between the outer ring gear (252) and the sub-drive gear (251) and transmitting the rotational driving force of the second motor (230) to the outer ring gear (252), and a gear shifter (260) is further included, which is installed in the housing (210) and selectively rotates or stops the rotation of the idler gear (253),
• wherein the gear shifter (260) includes:
• a plurality of dog grooves (261) formed in a cylindrical shape centered on the surface of the idler gear (253);
• a spline fixed shaft (262) which is fixed to the second housing (212) and has a rotation support groove (262a) formed at the tip thereof in which a rotation axis (253a) of the idler gear (253) is rotatably supported;
• a detachable ring (263) which moves forward and backward while not rotating relative to the spline fixed shaft (262);
• a dog tooth (264) formed on the front surface of the detachable ring (263) and which is detachable from the dog groove (261);
• and a selector (265) which moves the detachable ring (263) forward and backward so that the dog tooth (264) is coupled to or detached from the dog groove (261).