Patent ID: 11802568

Abstract:
A vacuum pump includes a linked-type thread-groove spacer which is a structure for linking a Siegbahn pump portion and a thread-groove pump portion, and when an outlet position of a thread groove which is an exhaust channel portion of this linked-type thread-groove spacer is in a vicinity of the stator portion (stator bolt) of the stator column, conductance of the exhaust channel is lowered. Thus, phases in a circumferential direction of installation positions of a thread ridge of the linked-type thread-groove spacer and the stator portion of the stator column are aligned as much as possible. In other words, the thread groove of the linked-type thread-groove spacer which is the exhaust channel is provided between the installation positions of the stator portions in the circumferential direction of the stator column so that lowering of the conductance of the exhaust channel is suppressed.