Abstract:In order to solve the problem of fixing the surface of the directdrive Computer Numerical Control(CNC) rotary when parts are progressed on it, a directdrive CNC rotary table of doublefaced brake mechanism is proposed. Combined with the structure of the brake mechanism, the brake torque of the mechanism was calculated by differential method.In order to further analyze the key part brake disk of the mechanism,the contact stress was analyzed by Ansys Workbench to obtain the stress and deformation of the brake disc.The maximum equivalent stress of the brake disc was 77.447 MPa, much smaller than allowable stress of brake disc. It showed that the strength of the brake disc met the design requirements.Modal analysis was used to obtain the first six natural frequencies and mode shapes.The results showed that the brake disc would generate resonance when the brake frequency was at 689.68, 864.65, 881.25 and 893.63(Hz). These frequencies should be avoided during parts processing to ensure machining accuracy.The actually brake torque is measured finally and compared with calculated value,which degree of coincidence is 93%, and the safety factor is 1.347 by calculation for the design agreed with requirement.The rationality of the brake mechanism and dependability of the work are verified.