| 摘要 |
<p>Disclosed is a cylindrical fixed member of a thread-groove exhaust pump unit, with which the cost of a vacuum pump can be reduced while the strength thereof against breakdown torque is maintained, in which thread grooves having complicated shapes of which width, depth, lead angle, and the like change in the rotation-axis direction of a rotating member of the thread-groove exhaust unit can be easily formed, and that is suitable for improving exhausting performance and compression performance of the entire vacuum pump by using such thread grooves. A cylindrical fixed member (thread-groove exhaust unit stator (18)) of a thread-groove exhaust unit (Ps) disposed so as to enclose the outer circumference of a rotating member (substantially the lower half of a rotor (6)) of the thread-groove exhaust unit (Ps) forms a helical thread-groove exhaust path (S) for exhausting gas between the rotating member and the cylindrical fixed member. This cylindrical fixed member includes two or more separable pieces (18A, 18B) that can be divided in the rotation-axis direction of the rotating member, and the separable pieces are joined together using a fastening means such as bolts or a joining means such as shrink fitting.</p> |
