Cylindrical fixed member of thread-groove exhaust unit and vacuum pump using same

Abstract

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.

Description

technical field [0001] The present invention relates to a cylindrical fixing member constituting a screw groove exhaust portion of a vacuum pump and a vacuum pump using the same, in particular capable of maintaining the strength of the vacuum pump against the torque generated when the rotor in the vacuum pump is destroyed (hereinafter referred to as "destruction torque"), and Reduce its cost, and at the same time, it is easy to make thread grooves on the cylindrical fixed part of the thread groove exhaust part. The corners and the like change and the shape is complicated. By adopting such thread grooves, the exhaust performance and compression performance of the vacuum pump as a whole can be improved. Background technique [0002] With the increase in diameter of wafers on semiconductor manufacturing equipment in recent years, vacuum pumps used in the equipment are required to achieve large-flow gas evacuation, low arrival pressure, and high evacuation performance. [0003]...

AI Technical Summary

Problems solved by technology

Therefore, it is not possible to use only low-strength castings to manufacture the entire cylindrical fixing part of the threaded groove exhaust portion.

In order to ensure the strength of the vacuum pump against the breaking moment, such cylindrical fixing parts must use expensive cutting parts obtained by cutting high-strength materials, such as materials manufactured by forging processing or push / pull processing, resulting in thread grooves The cylindrical fixing part of the exhaust part is the main cause of the high overall price of the vacuum pump

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