The present invention relates to a motor assembly of a new structure which improves a heat radiation function while minimizing the radiation of noise generated in the motor assembly through structural improvement for the motor assembly. Multiple first cooling holes connected with a space in which a motor part is located are formed on the front side of a front side housing. Multiple second cooling holes connected with the space in which the motor part is located are formed on one side between the circumference side of a rear side housing and the circumference.
