Patent ID: 11898565
Assignee: EDWARDS JAPAN LIMITED
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 4:
5. A linked-type thread groove spacer which is used in a vacuum pump having a casing in which an inlet port or an outlet port is formed, and a stator component enclosed in the casing, the linked-type thread groove spacer comprising:
a Siegbahn pump portion comprising a spiral groove comprising a first ridge portion, a second ridge portion and a root portion positioned between an outer side in a radial direction of the first ridge portion and inner side in the radial direction of the second ridge portion; and
a thread-groove pump portion linked to the Siegbahn pump portion, wherein
the linked-type thread groove spacer has a countersunk hole for a fixing bolt provided in an exhaust channel surface of the root portion in the Siegbahn pump portion, and is fastened to the casing or the stator component by the fixing bolt, wherein the countersunk hole is positioned closer to the outer side of the first ridge portion than the inner side of the second ridge portion.