VACUUM PUMP AND VACUUM APPARATUS

摘要

PURPOSE: A vacuum pump is provided to eliminate the disproportion of the pressure distribution of circumference and to prevent the flowing backward of the gaseous molecules toward the position without a pump. CONSTITUTION: The vacuum pump comprises:an inner case(22) communicated with the atmosphere and having a cavity(25) able to store a driving apparatus(86); an outer case(23) placed outside the inner case; an exterior body(21) including a lower annular plate(24) to close the space between the outer case and the inner case at one side; rotor wings(54) placed on the circumferential wall of a rotor body(52) by multiple steps; bearings(69, 60) to support the rotor body; and a motor(33) to rotate the rotor body. Therefore the distribution of pressure is made uniform.