JPS60234777A - Manufacture of rotor for turbo molecular pump - Google Patents

Abstract

PURPOSE:To enable assembling and diffusion joining without using assembling tools by forming step parts to one surface on the bore side of rotor rings and forming notches into which the step parts can be fitted to the other surface. CONSTITUTION:The many rotor rings 4 and vane plates 5 are alternately stacked to fit the socket and spigot joint parts consisting of the step parts 4a and notches 4b of the rotor rings 4 to each other. The many rotor fings 4 are exactly positioned and stacked to the plates 5. The assembly is installed in this state in a vacuum hot press and the inside of the press is evacuated to a vacuum; at the same time the assembly is heated to the temp. at which are Ti alloy is diffusively joined. The assembly is then pressurized from upper and lower directions and is thus diffusively joined.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for manufacturing a rotor of a turbomolecular pump,
In particular, the present invention relates to a method of manufacturing a rotor of a turbo-molecular pump suitable for diffusion bonding of the rotor of a turbo-molecular pump for ultra-high vacuum pumping used in nuclear fusion devices and the like.

[Background of the invention]

The rotor of a turbomolecular pump for ultra-high vacuum evacuation used in nuclear fusion devices, etc. is a high-speed rotating body that rotates several hundreds of times per minute. Therefore, in order to maintain the rotational balance of the entire rotor, the central axis of the entire rotor must be rotated. It must be produced with high precision.

First, FIG. 1 shows a method of manufacturing a rotor of a conventional turbomolecular pump.

FIG. 1 is a longitudinal sectional view showing an assembled state for diffusion bonding in a conventional method for manufacturing a rotor of a turbo-molecular pump.

A large number of rotor rings 1 and vanes 2 that have been divided in advance
These are stacked on top of each other and integrated by diffusion bonding.
As shown in Fig. 1, all of the joint surfaces that are stacked are flat, so the inner diameter of each rotor ring 1 and each vane plate 2 is machined with high precision, and the outer diameter of the assembly jig 3 is also adjusted to these values. Sufficient centering accuracy cannot be obtained unless it is machined with sufficient accuracy to match the inner diameter of the rotor base.

Furthermore, assembly is difficult without using the assembly jig 3.

Furthermore, since the rotor base is made of Ti alloy and the assembly jig is made of rigid steel, when the temperature is high, the difference in thermal expansion between the Ti-based alloy and the steel material causes the assembly jig to move from the inside of the rotor base to the outside. There was a concern that this would cause stress that would cause the material to bulge, resulting in poor diffusion bonding.

[Purpose of the invention]

The present invention was made in order to solve the problems of the prior art described above, and it is possible to assemble the rotor of a turbo-molecular pump without using an assembly jig and to diffusion bond the rotor of the turbo-molecular pump in that state. Its purpose is to provide a manufacturing method.

[Summary of the invention]

A method for manufacturing a rotor of a turbomolecular pump according to the present invention includes:
In a method for manufacturing a rotor for a turbo-molecular pump, in which a large number of rotor rings and vanes that have been split in advance are piled up and integrated by diffusion bonding, an inner diameter portion of the vane on one surface on the inner diameter side of the rotor ring; forming a stepped part higher than the thickness of the blade plate at a position where it can abut, and forming a notch on the other surface into which the stepped part can fit,
A method in which both of these parts can constitute a pilot part, a large number of rotor rings and vanes are stacked alternately, and diffusion bonding is performed with the pilot parts fitted together to integrate them. It is.

Additionally, the idea behind developing the present invention is as follows.

When manufacturing the rotor of a turbo molecular pump by diffusion bonding, the temperature must be raised to a temperature higher than room temperature. Therefore, if the materials of the rotor base and assembly jig are different, the difference in thermal expansion will cause the rotor base to Stress will be generated between the assembly jig and the assembly jig.

Therefore, it is conceivable to use a material for the assembly jig having a coefficient of thermal expansion similar to that of the rotor base material.

However, although Cr and Pt are conceivable as having thermal expansion coefficients almost the same as those of Ti-based alloys, they are not suitable for use as structural members.

Next, an assembly jig made of the same material as the rotor base may be considered, but since the Ti-based alloy used for this rotor base is an expensive material and a difficult-to-cut material, material costs and machining costs will be reduced. It ends up being expensive.

Therefore, we thought of giving the rotor ring itself the role of a jig. In other words, by providing a positioning protrusion and a groove in the corresponding part on the inside of the rotor ring, the blades can be positioned and the rotor base fixed, and a large number of rotor rings and blades can be assembled without using assembly jigs. We considered stacking them together and fixing them to perform diffusion bonding.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 2 to 5.

First, FIG. 2 shows parts used in a method for manufacturing a rotor of a turbo-molecular pump according to an embodiment of the present invention.
(a-], ) is a plan view showing 1/4 of a single rotor ring, (a-2) is a sectional view taken in the direction of arrow A in (a-1), (
b-B is a plan view showing 1/4 of a single wing plate, (b-2) is a sectional view taken along arrow B of (b-1), and Figure 3 is a longitudinal cross-section of the assembled parts. It is a diagram.

In FIG. 2, reference numeral 4 denotes a large number of rotor rings made of Ti alloy that have been divided in advance, and one surface on the inner diameter side of the rotor ring 4 has a stepped portion 4a, and the other surface has a notched portion 4.
It forms b.

Reference numeral 5 denotes a large number of vanes made of Ti alloy that have been divided in advance and are composed of a blade portion 5a and a disk portion 5b attached to the base of the rotor, and 5c indicates the inner diameter thereof.

The stepped portion 4a of the rotor ring 4 has an inner diameter 5 of the blade plate 5.
If h is the height of the first stepped portion 4a and d is the thickness of the disk portion 5b of the wing plate 5, then h>d is formed. There is.

Further, the cut portion 4b of the rotor ring 4 is a stepped portion 4a.
It is machined into a shape with one dimension that allows it to be fitted into a socket.

These many rotor rings 4 and vanes 5 are stacked alternately as shown in FIG.
By fitting the spigot parts of the notches 4a and 4b, a large number of rotor rings 4 and vanes 5 are accurately positioned and stacked, and no assembly jig is required.

In this state, place it in a vacuum hot press and hold it for 10'T.
At the same time as vacuum evacuation, the Ti alloy is heated to a temperature of 800° C. or higher, which is the temperature at which the Ti alloy is diffusion bonded, and pressure is applied from above and below at 0.2 kg/mm or more to effect diffusion bonding.

According to this embodiment, the rotor ring 4 and the blades 5 can be precisely assembled within the range of machining accuracy, so a rotor with small center axis deviation can be manufactured. Further, since no assembly jig is required, manufacturing costs can be reduced, and assembly can be completed in a short time, resulting in a reduction in man-hours.

Next, another embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a longitudinal cross-sectional view showing an assembled state using an insert material for diffusion bonding of the rotor of the turbo-molecular pump according to the embodiment shown in FIGS. 2 and 3; 3
Items with the same symbols as in the diagram indicate equivalent parts, so
The explanation will be omitted.

In Figure 4, 9 is the insert material, with A Q on both sides.
S'r co-conjugated alloy S i 9-11%) 16-19
This is AQ-8i brazing material with μm cladding.

Rotary tag 4. The blades 5 are pre-divided into the shapes described above, and their materials are all made of Ti-6AQ-4V alloy.

The insert material 9 is attached to the rotor ring 4 and the blade plate 5.
It is inserted between.

The AQ-8i eutectic layer formed on both sides of the insert material 9 has an AQ-8i eutectic temperature (580°C) during diffusion bonding.
At the above bonding temperature, it becomes a liquid phase, and the bonding surfaces of the blades 5 and rotor ring 4 are easily brought into close contact with each other at low pressure to promote diffusion.

The insert material is not limited to AQ-8i brazing material, but AQ or AQ alloy foil can be used as the rotoring material.
The insert material may be inserted between the blade plate 5 and the blade plate 5, and diffusion bonding may be performed by temporarily turning the insert material into a liquid phase during diffusion bonding. Further, AQ or AQ gold alloy may be thermally sprayed on the joint surfaces of the rotor ring 4 or the blade plate 5, or Mg and Si may be added.

This Mg is effective as a getter for oxygen in the atmosphere,
It plays a role in improving bonding properties through its reducing action.

Alternatively, an insert material in which a large amount of Si is added to lower the melting point of the insert material may be used.

As shown in FIG. 4, the assembled product is placed in a vacuum chamber, the chamber is evacuated to a vacuum level of 10' Torr, and then heated to 600°C. Next, each rotor ring 4 and each blade plate are pressurized from the top and bottom (axial direction) (0.5 kgf/nvn) while being maintained at a high vacuum and high temperature.Then, each rotor ring 4 and each blade are maintained in an isothermal and processing state for the required time (30 min). 5 is diffusion bonded.

In this case, only both sides of the AQ-8t brazing material 9 inserted between each rotor ring 4 and each blade plate 5 begin to melt at around 580°C during heating, and the diffusion bonding temperature is 6.
At 00°C, the vicinity of the joint surfaces between each rotor ring 4 and each vane plate 5 is in a liquid phase state. Therefore, when both 4 and 5 are pressurized from the axial direction, they are easily brought into close contact with each other at low pressure via the insert material 9 in a liquid phase, and mutual diffusion of Ti and AQ is also significantly promoted.

Also, when pressurizing, the excess liquid phase is removed from the rotor ring 4 and the vane plate 5.
Since only a very thin AQ alloy layer remains between the two and 4 and 5, there is no risk of reducing the joint strength, so the joint can be moved around with high reliability. .

Next, still another embodiment of the present invention will be described with reference to FIG.

FIG. 5 shows parts used in a method for manufacturing a rotor of a turbo-molecular pump according to still another embodiment of the present invention, and (a-1) is a plan view showing 1/4 of a single rotor ring. , (a-2) is a cross-sectional view of (a-1) in the direction of arrow C, and (b-
i) is a plan view showing a single wing plate 174, (b-2) is (
b-1) is a sectional view taken along arrow D.

In FIG. 5, reference numeral 6 denotes a large number of rotor rings made of Ti alloy that have been divided in advance, and one surface of the rotor ring 6 on the inner diameter side has a stepped portion 6a, and the other surface has a notched portion 6.
b is formed to have partial unevenness at equal intervals on the circumference.

In the previous embodiment, the stepped part and the cut part were provided all around the inner circumference, but in this embodiment, they are not provided all the way around, but only partially, and are spaced at equal intervals on the inner circumference when viewed from the center. It is designed to form partial unevenness on the surface.

Reference numeral 7 denotes a large number of vanes made of Ti alloy that have been divided in advance and are made up of a blade portion 7a and a disk portion 7b, and are provided with notches 7c so as to be able to conform to the irregularities on the inner circumference of the rotor ring. In this case, partial unevenness is formed at equal intervals on the circumference of the inner diameter portion.

Such a large number of rotor rings 6 and blade plates 7 are stacked alternately (not shown), and are adapted to the unevenness on the inner circumference of the rotor ring 6 and the unevenness on the inner circumference of the blade plate 7, and each Stepped portion 6a and cutout portion 6b of rotor ring 6
By fitting the spigot parts together, a large number of rotor rings 6 and vanes 7 are accurately positioned and stacked, and no assembly jig is required.

The following diffusion bonding operation is performed in the same manner as in the previous example.

According to the method of this embodiment, effects exactly the same as those of the previous embodiment can be expected.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a method for manufacturing a rotor of a turbo-molecular pump in which the rotor of a turbo-molecular pump can be assembled without using an assembly jig and then diffusion bonded in that state. can.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an assembled state for diffusion bonding in a conventional method for manufacturing a rotor of a turbo-molecular pump;
FIG. 2 shows parts used in a method for manufacturing a rotor of a turbo-molecular pump according to an embodiment of the present invention.
-1) is a plan view showing 1/4 of a single rotor ring, (a
-2) is a sectional view of (a -1) in the direction of arrow A, (b -1,
) is a plan view showing 1/4 of a single wing plate, (b-2) is,
(b-1) is a sectional view taken along arrow B, FIG. 3 is a longitudinal sectional view of the assembled parts, and FIG.
FIG. 5 is a longitudinal cross-sectional view showing an assembled state using an insert material for diffusion bonding of the rotor of the turbo-molecular pump according to the embodiment shown in the figure. It shows the parts used in the rotor manufacturing method, where (a-1) is a plan view showing 1/4 of a single rotor ring, and (a-2) is a cross section viewed from point C in (a-1). figure,
(+) -1) is a plan view showing ]/4 of a single wing plate, (b
-2) is a sectional view taken along arrow D in (b-1). 4.6...Rotor ring, 4a, 6a...Stepped part,
4-b, 6. b...notch part, 5,7...-wing plate, 5c...
・Inner diameter part, 7C...notch. Agent Patent Attorney Akio Takahashi No. 1 Fig. 1 Z Fig. 3 Fig. 4

Claims (1)

[Claims] 1. In a method for manufacturing a rotor for a turbo-molecular pump, in which a large number of rotor rings and vanes that have been divided in advance are piled up and integrated by diffusion bonding, one of the rotor rings on the inner diameter side A stepped portion is formed higher than the thickness of the blade plate at a position where the inner diameter portion of the blade plate can come into contact with the surface, and a notch portion into which the stepped portion can fit is formed on the other surface. A number of rotor rings and vanes are stacked alternately, and diffusion bonding is performed with the pilot parts fitted together to integrate them. A method for manufacturing a rotor for a turbomolecular pump. 2. In the method described in claim 1, the stepped portion on one surface on the inner diameter side of the rotor ring and the notch portion on the other surface are formed to be partially uneven on the circumference. In addition, a method for manufacturing a rotor for a turbo molecular pump, wherein the inner diameter side of the vane plate is formed with unevenness that can match the unevenness of the rotor ring. 3. In either of the methods described in claim 1 or 2, a turbo is provided in which an insert material with a low melting point is interposed between the rotor ring and the blade plate, and these are stacked one on top of the other. How to make a rotor for a molecular pump. 4. A method for manufacturing a rotor for a turbo-molecular pump, in which the material of the rotor ring and blades is a Ti group metal, according to any of the methods described in claim 1 or 2. 5. A method for manufacturing a rotor for a turbo-molecular pump according to claim 3, wherein the low-melting point insert material is AQ or an AQ-based alloy.