JPS60201003A - Ceramic rotor and manufacture thereof - Google Patents

Abstract

PURPOSE:To enhance the mass productivity of a ceramic rotor by a method in which the center of a shaft is fixed by holes drilled in both end portions on the center line of the shaft molded of ceramics, and the shaft is subjected to a polishing process while being turned. CONSTITUTION:A ceramic molding 5 consisting of a disc part and a shaft is subjected to hydrostatic pressure, and holes 51 and 52 are drilled in both end portions on the center line of the shaft. The center of the shaft is fixed by the holes 51 and 52, and while turning the disc part and the shaft part, the molding 5 is subjected to a polishing process. Since the needs to attach the ceramic molding 5 to the other object with the aid of an adhesive is eliminated, the mass productivity of the ceramic rotors can be raised with a high easiness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ceramic rotor that is excellent in mass productivity and quality.

In recent years, attention has been focused on the heat resistance of ceramics, and it has been desired to use ceramics for engine peripheral parts, especially turbine rotors used in turbochargers and the like. In general, high-speed rotating bodies are required to have good dynamic balance, and turbine rotors also require fairly good dynamic balance because they rotate at a speed of several tens of thousands of revolutions per minute. However, ceramic molded bodies undergo deformation and dimensional variations due to firing shrinkage, so in order to satisfy the above requirements, a long polishing process must be performed after firing. In traditional rotor manufacturing methods,
Both end surfaces of the fired body that will become the rotor are glued to a separate body such as a metal body using an epoxy resin adhesive, and while checking the balance by rotating the fired body, the position is approximately on the axial center line of the separate body. A hole was drilled in the hole, and the fired body was polished using a diamond whetstone while rotating around the line connecting the holes. In some cases, a hole is drilled in advance at the center of the axis of a separate body, and the fired body is polished by adhering it to both end surfaces of the separate body. However, in either case, it is troublesome as it is necessary to separate the separate body from the fired body after one sharpening and scrape off unnecessary parts such as adhesives attached to both end faces of the fired body, and it is difficult to use a diamond whetstone. Since it has to be used, processing costs are high. In addition, in the latter case, it was difficult to align the hole drilled in a separate body with the axial center line of the fired body.

The present invention overcomes the above-mentioned difficulties, and the ceramic molded body of the impeller part and the shaft has a weight of 500 kg/cm2.
After applying the above hydrostatic pressure, a hole is bored in the side end surface on the shaft center line, the shaft center is fixed with these two holes, and the impeller part and shaft are polished while rotating and fired. The present invention provides a method for manufacturing a ceramic rotor characterized by the following, and a ceramic rotor manufactured by the method.

The present invention will be explained below based on the drawings.

FIG. 1 is a cross-sectional view of a ceramic molded body showing an example of the initial stage of the manufacturing method of the present invention. Reference numeral 1 indicates the ceramic molded body, in which a blade wheel portion 11 and a shaft 12 are integrally molded. 21st
The figure is a sectional view of a ceramic molded body showing another example of the initial stage of the manufacturing method of the present invention, and 2 shows the ceramic molded body,
After separately molding the impeller part 21 and the shaft 22, one end of the shaft 22 is fitted and fixed into the knob hole of the impeller part 21.

The above molded bodies are made by injection molding and slurry casting.

The molded body may be molded according to a well-known molding method such as a powder pressure molding method or by a combination of these molding methods, but at this stage, the molded body is a non-uniform molded body in which the filling state of ceramic particles differs depending on the molded location. For example, in the case of injection molding, there is often a difference in green density between the vicinity of the injection port and other parts of the molding base. If this heterogeneous state is fired without any correction treatment, significant deformation will occur due to the difference in shrinkage rate. The first point of the present invention is to apply 500 h/h to such a heterogeneous molded body.
The purpose is to apply a hydrostatic pressure of 1 yyr2 or more. In other words, when pressure is applied uniformly from all directions, the particles move from dense areas to sparse areas inside the molded body, eliminating unevenness in the filling state of particles, which can minimize firing deformation. It's there. This effect is due to the hydrostatic pressure of 5001g
/ cm2, it will not appear. Furthermore, if the molded article contains an organic component such as a binder, it is desirable to apply hydrostatic pressure after degreasing. The second point of the present invention is that after applying the above-mentioned hydrostatic pressure, holes are formed in the side end surfaces of the ceramic molded bodies 1 and 2 on the axial center line. In other words, the green density and green strength of the green body are improved by the above-mentioned hydrostatic pressurization, so if the axial center is fixed with the two holes on the side end surface, the green body can be rotated and easily ground and polished. Furthermore, the polished molded body hardly undergoes firing deformation even if it is subjected to the above-mentioned through-firing, so that processing after polishing is unnecessary. At this point, the hydrostatic pressure is 500
kg/t, yr 12 or more is required, and i, oo is required to facilitate the drilling of holes.

ig,/cm2 or more is desirable. Therefore, it is possible to avoid the trouble associated with adhering and separating separate bodies such as metal bodies, which was conventionally used, and the tool does not require a diamond whetstone; a Go whetstone is sufficient for processing. This means that wages can be reduced. Such a hole may be formed to the minimum size that only has the function of fixing the shaft center as described above, but when a metal shaft is joined to the oil gear rally side end surface of the rotor shaft, it may be formed as shown in FIG. 6. two holes 3
．． If the hole 4 on the oil gear rally side end surface of 4 is formed by a small diameter part 4a for the purpose of fixing the shaft center and a large diameter part 4b that is connected to this small diameter part 4a and is also shallow, then
The large diameter portion has a function of insulating heat transmitted from the impeller side after joining with the metal shaft. In this structure, a heat insulating hole is provided at the joint with the metal shaft, or, although not shown, in a structure in which the impeller and shaft are separately molded and the two are joined, a cavity is provided at the joint.41 ``Turbine shaft joining 4'' was invented by the applicant in Japanese Patent Application No. 58-208344.
1 degree 11 construction" or the patent application invention "Turbine shaft" dated December 19, 1981. However, the present invention has a large diameter portion 4b formed by the heat insulating hole and a small diameter portion 1≦
There is an advantage that drilling can be performed simultaneously with 4a. The molded body thus polished is fired and becomes a ceramic rotor with good dynamic balance. FIG. 4 is a cross-sectional view of a ceramic rotor obtained by processing and firing the ceramic molded body 1 of FIG. 1 according to the manufacturing method of the present invention. ．．
52.

Examples are shown below.

Example 1 Heavy 111. As standard, α-8i3 with an average particle size of 0.611 m
N4 powder 89, Y2O35.5% and AI! ,085
, 5% was mixed in ethanol using an alumina thoron mill for 50 hours, and after drying, 13 parts of atactic polypropylene, 5 parts of paraffin, and 6 parts of diethyl ntalate were added to 100 parts of the total inorganic powder, and the mixture was heated and kneaded at a temperature of 80°C. Then, it was made into pellets using a pelletizer. This pellet was injected into an injection molding machine, and the impeller part 11 and shaft 12 were integrally molded as shown in Fig. 7, and heated to 50'C at a heating rate of 1.5°C/)1r.
After heating and degreasing the molded body, and applying the hydrostatic pressure shown in Table 1, the molded body was rotated to observe the eccentricity of the shaft 12 and the perpendicularity of the hub part rear shaft 121 of the impeller part 11. Holes were made with a drill at positions substantially on the axial center line of both end faces of the molded body. Ten molded bodies were made at different hydrostatic pressures, and the success rate of hole drilling was investigated. Table 1 shows the results.

Table 1 Note *υ Drilling success rate In the case of compacts to which no hydrostatic pressure was applied, 4 out of 10 were destroyed during the drilling process, and 4 more had hole chipping, so the success rate was set at 20%. , and the hydrostatic pressure is 0.5 tonA! In the case of the molded product with 12 added, hole chipping occurred in 4 out of 10, so the success rate was reduced to 60.
%.

*2) The difference between the maximum and minimum radius when rotating with any one point on the circumference 5a as 0 point was taken as the maximum swing width of the circumference 5a.

It can be seen from Table 1 that the molded articles within the scope of the present invention have sufficient green strength to facilitate processing. Next, the molded body was rotated with the axial center fixed through two holes drilled in both end faces, and polished using a GO grindstone so that the molded body became axially symmetrical while observing the axial direction. Thereafter, the ceramic rotor 5 shown in FIG. 4 was manufactured by firing at a temperature of 1600° C. in a nitrogen atmosphere. Fix the shaft center with two holes 51 and 52 on one side of both ends of the ceramic rotor 5,
The average value of the results of measuring the maximum amplitude of the circumference 5a of the back surface of the hub portion when the ceramic rotor 5 is rotated is also listed in Table 1. For comparison, a molded body was fired without either hydrostatic pressure treatment or hole drilling, and a separate metal body was adhered to both end surfaces of the fired body with an epoxy adhesive.
A hole is drilled at a position approximately on the axial center line of the separate body, and while the fired body is rotated around a line connecting these two holes, the blade wheel portion and the shaft are By polishing the outer circumference of the ceramic rotor 5, a ceramic rotor having the same shape as the ceramic rotor 5 described above except that it does not have the holes 51 and 52 is manufactured. The average value of the results of measuring the maximum amplitude of vibration is also listed in Table 1. Note that the diameter of the back surface of the hub portion was all 45mm. As shown in Table 1, 5,001g/ty is within the scope of the present invention.
The one to which a hydrostatic pressure of s2 or more was applied had a vibration amplitude as small as the comparative example and had a good dynamic balance, but the one to which no hydrostatic pressure was applied had a large vibration amplitude and a poor dynamic balance. there were.

Example 2 β-8iO powder 96 with an average particle size of 0; 2 μm on a weight basis
parts, 2 parts of boron carbide, 2 parts of carbon and 0 parts of sodium alginate
．． 5 parts were wet-mixed to form a slurry, poured into a mold and cast, and then the hydrostatic pressure shown in Table 2 was applied to produce a molded body having the same shape as the molded body of Example 1, the same as in Example 1. Holes were drilled at positions estimated to be approximately on the axial center line of both end faces of the molded body. Table 2 shows the results of examining the success rate of hole drilling in 10 molded bodies at different hydrostatic pressures.

Note to Table 2: Drilling success rate In the case of molded bodies to which no hydrostatic pressure was applied, 10 pieces were destroyed during the drilling process, and four more had hole chipping, so the success rate was set as 0%. In addition, in the case of a molded body to which a hydrostatic pressure of 0.5 ton/α2 is applied, 10
Since hole chipping occurred in each case, the success rate was set at 60%.

Table 2 shows that the molded articles within the scope of the present invention have sufficient green strength to facilitate processing.

Next, the axial center was fixed with two holes drilled in both end faces, the molded body was rotated, and the molded body was polished in the same manner as in Example 1, and then fired in a vacuum at a temperature of 2100'Q. A ceramic rotor 3 shown in FIG. 2 was manufactured. As in Example 1, the average value of the results of measuring the maximum swing width of the circumference 5a on the back surface of the hub portion is also shown in Table 2.

As shown in Table 2, 500 is within the scope of the present invention.
, kg/cm2 or more of hydrostatic pressure was applied, the amplitude of vibration was as small as that of the comparative example shown in Example 1, and the dynamic balance was good, but the vibration amplitude of the specimen to which hydrostatic pressure was not applied was small. It was wide and had poor dynamic balance.

Example 6 A pellet with the same composition as Example 1 was injected into an injection molding machine,
After molding the impeller part and the shaft separately and degreasing both parts, insert the shaft 2 into the hub hole of the prefect wheel part 21 as shown in FIG.
Molded bodies were produced under the same conditions as in Example 1, except that one end of 2 was fitted and fixed, and the hydrostatic pressure shown in Table 3 was applied. Holes were drilled in 10 molded bodies for each different hydrostatic pressure. Table 3 shows the results of examining the processing success rate. In addition, the molded body with holes drilled therein was polished in the same manner as in Example 1.
By firing under the same conditions as above, a ceramic rotor (not shown) having the same external shape as the ceramic rotor 5 shown in Example 1 was manufactured. The maximum amplitude was measured in the same manner as in Example 1, and the average value is also shown in Table 1.

Table 3 It can be seen from Table 3 that even when the impeller part and the shaft are molded separately, the molded bodies within the scope of the present invention have sufficient green strength to be easily processed. Further, it can be seen that the ceramic rotor of the present invention has a good anti-drive balance as well as the comparative example shown in Example 1.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a ceramic molded body showing an example of the initial stage of the manufacturing method of the present invention, FIGS. 2 and 3 are cross-sectional views of a ceramic molded body showing other examples, and FIG. FIG. 2 is a cross-sectional view of a ceramic rotor obtained by processing and firing a ceramic molded body according to the manufacturing method of the present invention. 1.2... Ceramic molded body, 11.21... Impeller part, 12.22... Shaft, 3.4.51.52... One hole,
4a...Small diameter part, 4b...Large diameter part, 5...Ceramic rotor representative Patent attorney Mamoru Takeuchi Figure 1 Figure 2 Figure 3 Figure 4 Procedure Tadashi Sode -1) - (Voluntary initiative) ) Showa, ↑1+ 597rP-January 25th Patent Office Officer Wakasugi >U Husband 1. Indication of the case 1987 special it'f copy No. 57336 2. Name of the invention Ceramic rotor and its manufacturing method 3. Ministry of Justice 4 (Article 11-Applicant Address: Nago, Aichi Prefecture) 1, Mizuho-ku, Rui City (Mutsuji+or 14)
City No. 18 Name Title (454) Nippon Tokushu Toto Co., Ltd. Representative name Shuji Ogawa 4.1 (Buried 101 Address Yu!Lkyo!ili Chiyoda-ku Enjin 1j4 2-chome [1
No. 15, No. 13, No. 6 amendment to the invention that changed the species to 1 (1) Corrected shell - 1 copy of the deceased, (2) Reason - 1 copy of JF (
(Attachment) (1) Add the statement "(%iiT' application pursuant to Article 38 of the Patent Act, however, Article I)" to the application plan. (2) Next to Ganki's "1. Title of invention" column, enter r2. '
i Request for permission 1 (jjj, number of inventions stated in the box 2
” to join. (3) Therefore, the item numbers in the application are 1, title of the invention, 2
Particularly, the scope of the invention set forth in the claims, 3. Special 1'F applicant, 5° agent, 6. Attached is the catalog of the expedition, ``origins other than D'l iiQ''. (4) In the description of the inventors in the application, the phrase ``4i5J r Pi or 4 people'' is corrected to ``3 other people''.

Claims (1)

[Claims] 1) A ceramic rotor characterized by having holes on both end faces on the axis center line. 2) The ceramic rotor according to claim 1, wherein the hole includes a hole on both end faces of the oil gear rally, or a small diameter portion, and a large diameter portion that is connected to the small diameter portion and is also shallower than the small diameter portion. 5) 500 g on the ceramic molded body consisting of the wheel part and shaft.
After applying a hydrostatic pressure of kg/cm2 or more, holes are drilled in both end faces on the shaft center line, and the shaft center is fixed with these two holes, and the impeller part and shaft are prevented from rotating. A method for manufacturing a ceramic rotor, which includes grinding and firing.