Gearbox of numerically-controlled vertical lathe

The utility model discloses a gearbox of a numerically-controlled vertical lathe. The gearbox comprises an upper box body, a lower box body, a coupling body and a motor base, and adopts a structure with two-piece unit. A main motor sits on the lower box body through the motor base; the motor shaft is coupled with a shaft I through a coupler; the power of the motor shaft is transmitted to a shaft II and a lower box shaft III through a speed-reduction gear; the lower box shaft III is coupled with an upper box shaft III through a splined coupling sleeve and transmits power; a shaft VI in a workbench transmits power to a large gear ring through a gear, a shaft IV, and a shaft V, and the power transmitted by the workbench is then transmitted to a workbench base after hydraulic control machinery changes speed through two gears. The gearbox has the benefits of high precision, high transmission efficiency, high transmission rigidity, simple and compact structure, low manufacturing cost, low noise, high reliability, a