VACUUM PUMP AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a vacuum pump wherein mechanical damage to a protective net and rotor vanes is prevented by stabilizing the shape of the protective net, and also to provide a manufacturing method of the pump. SOLUTION: The vacuum pump is provided with a protective net comprising an annular rib 22 suitable for a suction port and a net part 23 formed inside the annular rib 22. The net part 23 is sectioned in the radial direction of the rib 22 into a plurality of flat parts 23f, and a plurality of stepped parts 23s. The flat parts 23f are positioned in different locations in the direction of an shaft C so that the distance to the rotor vanes becomes larger as the net part comes closer to the shaft C. The stepped parts 23s joint the respective flat parts 23f, which are adjacent in the radial direction of the shaft C, almost along the axial direction of the shaft C. COPYRIGHT: (C)2009,JPO&INPIT