| 摘要 |
PROBLEM TO BE SOLVED: To improve an efficiency of a motor by prescribing the sheet thickness, surface roughness, specific resistance and grain diameter of a steel sheet. SOLUTION: The sheet thickness is regulated to 0.3 to 0.6mm. In the case of less than the lower limit, the rigidity of the steel is made insufficient, and in the case of more than the upper limit, core loss increases. The surfaced roughness is regulated to <=0.6μm. In the case of more than that, the occupying volume rate at the time of laminating cores reduces and to reduce the magnetic flux density per effective cross-sectional area. The specific resistance is regulated to 40 to 75μΩ.cm. The grain diameter (after stress relieving annealing) is regulated to 40 to 120μm. In the case of fine grains of less than the lower limit, the magnetic flux density is inferior, and the objective magnetic characteristics can not be obtd. In the case of more than the upper limit, core loss of high frequency deteriorates, and the efficiency of a motor does not improve. |
