In accordance with fundamental theory of conjugate mesh

a perfect modification of profile(PMP)method was analyzed for a 6-teeth inner rotor and a 7-teeth outer one. The modified outer rotor could mesh with the inner rotor perfectly and the minimal dead volume could beachieved. Though PMP method can not be applied easily

it is the assessment boundary of other modification methods. Moreover

a feasible method called arc modification of profile(AMP)method was proposed. This method is much simpler and can be adopted in the practical machining process. AMP method could also obtain a smaller dead volume and the machining cost could decrease sharply. The present study of the profile modifications is useful for the application of internal-meshing cycloid rotary compressors.