JPH03237295A - Turbo-molecular pump - Google Patents

Abstract

PURPOSE:To shorten the shaft length of a pump itself so as to reduce its size and weight by connecting respective rotary vanes of a molecular pump to ring shaped-rotators of a ring type electric motor. CONSTITUTION:An annular holding cylinder 5 for storing and holding fixedly a ring shaped outer stator 6 and a ring-shaped inner stator 7 which are arranged face to face at a constant interval, is inserted around the top part of the central fixed holding shaft 4. And a ring shaped-rotator 8 is inserted into the clearance between the outer stator 6 and the inner stator 7, and the top end thereof is fixed through a connecting annulus 9 integratedly on a rotary cylinder 10 which is the base of a rotary vane 3. The rotary cylinder 10 is supported by magnetic bearings 12, 13, and the magnetic bearing 12 is maintained by a supporting annulus 14 fixed on a fixed holding shaft 4. The rotary vans 3, 3' are driven in high rotating speed by two upper and lower ring shaped-electric motors RM, RM' so as to carry out exhaust.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Application Field This invention relates to a turbomolecular pump that directs the flow of molecules and exhausts gas molecules to create a vacuum using a turbo mechanism based on the relative rotation of fixed blades and rotary blades. It is something.

B. Prior Art In conventional turbo-molecular pumps of this type, the rotor blades are rotated by an electric motor, but the output of the electric motor is The rotor blade is directly connected to the shaft end. This configuration applies not only to the vertical type but also to the horizontal type.

C4 Problems to be solved by the invention In the case of conventional turbomolecular pumps, the rotary blades and fixed blades are combined in multiple stages, but they are integrated and are driven to rotate by a single electric motor. It is configured. Therefore, in order to change the exhaust characteristics of each stage, it is necessary to change the size of the blades. However, in this case, processing becomes complicated. On the other hand, since the rotor blade is connected to the end of the output shaft of the electric motor, the axial length of the entire pump must be extremely large.

If the capacity is large, the motor will be large and this tendency will increase. An increase in the shaft core length results in an increase in the size and weight of the pump.

The present invention aims to provide a turbomolecular pump that solves these problems.

Means for Solving Problem D1 The turbo-molecular pump according to the present invention employs a ring-type motor as the motor, and a plurality of these motors are installed. This ring-shaped electric motor consists of an outer stator and an inner stator that are placed opposite each other with a certain gap between them, and a ring-shaped rotor that is inserted into these gaps, and the electromagnetic force between the inner stator and the rotor is It is configured to generate torque in the ring-shaped rotor by its action. The rotor blades of the molecular pump are connected to each ring-shaped rotor of this ring-shaped electric motor. At the same time, the drive of each electric motor is controlled separately.

E. Effect Since the rotor blades of the molecular pump connected to the ring-shaped rotor can be located inside or outside the ring, the axial length becomes the axial length of the ring-shaped electric motor. Therefore, the ring type electric motor can be installed in multiple stages in the axial direction.

F. Practical Knee Example The present invention will now be described according to the embodiment shown in the drawings.

FIG. 1 is a longitudinal cross-sectional view showing the entire configuration of a turbomolecular pump according to the present invention, and FIG.
It is an I side view. FIG. 2 is for explaining the structure of a ring type electric motor, and shows a cross section perpendicular to its axis. FIG. 3 shows a control circuit for each ring type motor.

The illustrated example shows an example in which ring-shaped motors are installed in two stages, and the lower stage is the same as the upper stage, so the symbols are -
It is shown with . The explanation of the turbomolecular pump and ring type electric motor will focus on the upper part.

First, the structure of a turbo-molecular pump will be explained in accordance with FIG. 1. In FIG. 0, reference numeral 2 denotes fixed blades, which are fixedly attached to the inner wall of the pump casing 1 in multiple stages at regular intervals. Reference numeral 3 designates rotor blades which are fixedly attached to the rotary cylinder 10 in multiple stages at regular intervals and extend outward from the fixed blade 2.

The fixed blades 2 and the rotary blades 3 are alternately combined to form a turbo mechanism. Then, the high-speed rotation of the rotor blade 3 creates relative rotation between the fixed blade 2 and the rotor blade 3, directs the flow of molecules, and discharges gas molecules from the intake port P to the exhaust port H, which is connected to the intake port P. Exhaust chamber (
(not shown) to obtain a vacuum. 15 is a leg.

The above is no different from the conventional technology and is a known technology.

The present invention is characterized in that, in the above configuration, the rotary blades 3 and 3 are rotated at high speed by the ring-shaped electric motor RM.

This point will be explained with reference to FIG. That is, in the figure, 5 is a part of the ring-shaped electric motor RH, and is an annular holder that fixedly houses and holds the ring-shaped outer stator 6 and inner stator 7, which are arranged opposite to each other with a certain gap. It is a cylinder and is fitted into the upper part of the fixed holding shaft 4 in the center. A ring-shaped rotor 8 is inserted into the gap between the outer stator 6 and the inner stator 7, and its upper end is integrally fixed to the rotary cylinder 10 via a connecting ring 9. This rotary cylinder 10 serves as the base of the rotor blade 3.

This rotary cylinder 10 is supported by magnetic bearing arrangements 12.13. The magnetic bearing device 12 is held by a support ring 14 fixed to the fixed holding shaft 4 . The magnetic bearing device 13 is constituted by the inner annular portion of the rotating cylinder 10.

Therefore, the rotary blades 3 and 3 are driven to rotate at high speed by the two upper and lower ring-shaped electric motors RHRH, thereby performing exhaust gas.

Furthermore, the two upper and lower ring motors RHRM are individually controlled by a drive control circuit CB as shown in FIG. ES comes out from the power supply section. This drive control circuit CB operates according to the degree of vacuum in the chamber C to be evacuated. That is, the degree of vacuum in the chamber C to be evacuated is sensed by the sensor S, and a signal corresponding to the degree of vacuum is input from the detector to the drive control circuit CB. The drive control circuit C8 receives the input and controls two ring-shaped electric fi
The RHRHs are rotated at appropriate speeds.

The features of the present invention are as described above, but are not limited to the above and illustrated examples.
They may be installed in stages, and the rotational speed may not be controlled according to the vacuum degree of the chamber to be evacuated, but may be controlled manually as needed.

This invention includes all of these.

G3 Effects of the Invention Since the present invention has been described above, the exhaust characteristics can be adjusted by controlling the rotational speed of each ring type electric motor, and there is no need to change the size of each turbo mechanism. Therefore, the blades of the turbo mechanism can have the same size, which is advantageous for processing, maintenance, etc.

Moreover, the shaft length of the pump itself can be made as short as possible, making the pump compact.
It is possible to reduce the weight.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing the entire configuration of a turbomolecular pump according to the present invention, FIG. 2 is a side view of FIG. 1, and FIG.
The figure is a control circuit diagram. 1... Pump casing, 2... Fixed blade, 3...
Rotor blade 4... fixed holding shaft, 5... annular holding cylinder.

Claims (2)

[Claims] (1) A molecular pump that directs the flow of molecules and generates a vacuum by discharging gas molecules by using a turbo mechanism based on the relative rotation of a fixed blade and a rotary blade, in which a plurality of the turbo mechanisms are provided, and each turbo mechanism A turbo-molecular pump characterized by having a control mechanism for separately controlling the rotational drive of the rotor blades in the pump. (2) A molecular pump that generates a vacuum by directing the flow of molecules and discharging gas molecules using a turbo mechanism based on the relative rotation of fixed blades and rotary blades, with outer stators facing each other with a certain gap in between. and an inner stator, and a ring-shaped rotor inserted into these gaps, and a plurality of ring-shaped electric motors are provided that generate torque in the ring-shaped rotor by electromagnetic force between both stators and the rotor. A turbo-molecular pump characterized in that a rotor blade of the molecular pump is connected to the ring-shaped rotor of each ring-shaped electric motor, and a control mechanism is provided for controlling the rotational drive of each ring-shaped electric motor.