MACHINE TOOL HAVING COOLING TYPE MOTOR SPINDLE

PURPOSE: To effectively perform the cooling of a main motor by providing a main motor coaxially with a spindle shaft, which comprises a rotor, a stator and a cooling device and by directly introducing a gaseous cooling liquid along the cooling surface of a stator plate. CONSTITUTION: A main motor 28 is assembled into a spindle motor, and a rotor 32 and a stator 36 are assembled into the motor 28. The rotor 32 is formed of a plurality of rotor plates 52, and an air gap 58 is provided between the outer circumference part 54 of the rotor plates 52 and the internal surface 56 of the stator 36. A plurality of cooling fins 86 are formed of the projection part of a stator plate 60, and the fins are formed of a plurality of cooling channels 88 and set in the external surface 68 of a primary set 62. A cooler 98 for introducing air from a fan 96 is fitted between an air introduction channel 94 and an air gap channel 92, thereby cooling the air introduced into the air gap channel 92. Therefore, the cooling of the main motor 28 can be effectively performed.