JPH0283155A - Working method for ceramics rotor - Google Patents

Abstract

PURPOSE:To constrain the rotary unbalance generated on an obtd. work smaller and to reduce a defective part generation rate by deciding a rotary shaft center at reverse center working time based on the rotor shaft decided as the center shaft of a rotor main body part. CONSTITUTION:The outer peripheral face of the large diameter side end part of a hub part 12 is taken as the center reference of a rotor shaft and the projecting end face of a back plate 18 as the inclination reference of the rotor shaft, such a ceramics rotor 10 is held on a specified 1st work jig 40, and a conical reverse center is formed by executing grinding on the one part of the projecting end part 36 of a shaft part. Then, the ceramics rotor 10 is held on a specified 2nd work jig with the reverse center formed on one part of the shaft part and the outer peripheral face of the large diameter side end part of the hub part as the reference, and a conical reverse center is formed by executing grinding at the projecting end part of the other part of the shaft part of the ceramics rotor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a method for easily and advantageously carrying out reverse center processing for determining the rotation center axis of a fired body when manufacturing a ceramic rotor. This relates to possible processing methods.

(Background Art) In recent years, as shown in Japanese Unexamined Patent Publication No. 55-134701, etc., turbine rotors used in gas turbine engines, turbochargers, etc. have been manufactured using predetermined ceramic materials such as silicon ceramics. Ceramic rotors have been increasingly used because of their heat resistance, corrosion resistance, and light weight.

By the way, in such a ceramic rotor,
Usually, by molding and firing a predetermined ceramic material, a substantially truncated conical hub portion with a plurality of blades on the outer circumferential surface and a hub portion coaxially protruding onto the large-diameter end surface of the hub portion are formed. It integrally includes a disk-shaped back plate having a predetermined thickness, and a shaft portion coaxially protruding outward from the small-diameter side end face of the hub portion and the axial end face of the back plate, respectively. However, since such a ceramic rotor is used under high-speed rotation, the resulting fired body is subject to static and dynamic effects around its rotation center axis. It is necessary to adjust the rotational balance.

In order to adjust the rotational balance of such a ceramic rotor, it is first necessary to determine its rotational center axis, and for this purpose, one of the shaft portions of the fired product is usually held by a collet chuck or the like. By grinding the end of the other shaft while rotating it around the shaft, a conical shape rotatably supported by a predetermined center member is formed on the protruding ends of both shafts. A so-called reverse center processing will be performed to form a reverse center.

However, the central axis of the shaft of such a fired body generally does not coincide with the central axis of the hub of the ceramic rotor body, and therefore the central axis of the shaft is set as the central axis of rotation. As a result, the amount of rotational imbalance becomes significantly large. Since ceramics are more difficult to process than metals, it takes a lot of time to adjust the balance by polishing or the like, and in some cases it is impossible to adjust the balance by grinding or the like.

Therefore, in the past, in order to make the initial unbalance smaller than that of a metal rotor, the shaft of the fired body is held by a chuck, etc., and then the eccentricity of the hub, etc. with respect to the central axis of the shaft is It was necessary to determine the center axis of rotation for each fired body by measuring it with a dial gauge, etc., and correcting the deviation according to the measured value. ,
Such reverse center machining requires a great deal of labor and time, and the work itself requires skill.

(Problems to be Solved by the Invention) In addition, especially in recent years when turbochargers are being installed in vehicle engines and rotors are being made of ceramics, there is a strong desire to improve the productivity and reduce manufacturing costs of ceramic rotors. Therefore, there is a strong need for an improvement in the method for processing the reverse center of fired products as described above.

It is an object of the present invention to simply, easily, and advantageously carry out reverse center machining to determine the center axis of rotation of a fired body when manufacturing a ceramic rotor, without requiring any skill. The goal is to realize a processing method that can do this.

(Means for solving the problem) In order to solve the problem, the present invention includes:
A hub part of a turbocharger rotor, a gas turbine, etc., which has a substantially truncated conical shape with a plurality of blades on the outer circumferential surface, and a hub part of a predetermined thickness coaxially protruding from the large-diameter end face of the hub part. integrally molded using a predetermined ceramic material, having a disk-shaped back plate and a shaft portion coaxially protruding outward from the small-diameter end face of the hub portion and the protruding end face of the back plate; In the fired ceramic rotor, when performing reverse center processing on the protruding ends of both shaft parts, the outer peripheral surface of the large diameter end of the hub part is used as the center reference of the rotor shaft, and the protruding end of the back plate is The ceramic rotor is held in a predetermined first processing jig, using the end face as a reference for inclination of the rotor axis, and one protruding end of the shaft is ground to form a conical inverted center. death,
Further, the ceramic rotor is held in a predetermined second processing jig with reference to the reverse center formed on the one shaft portion and the outer peripheral surface of the large diameter end of the hub portion. The method of processing a ceramic rotor is characterized in that a conical inverted center is formed by grinding the protruding end of the other shaft of the ceramic rotor.

Further, in the present invention, when processing a ceramic rotor according to such a method, the first processing jig includes (a)
(b) a large diameter hub portion of the ceramic rotor that is moved toward and away from the ceramic rotor of the chuck body toward the central axis of the chuck body; (C) three claws that contact the outer circumferential surface of the side end and cooperate with each other to grip;
The inner hole is located at the center of the surface of the chuck body, projects at a predetermined height above the surface of the chuck body, and has an inner hole that is open at least at the end surface of the protrusion side, and the end surface of the protrusion side is located at the center of the surface of the chuck body. The chuck is a three-jaw scroll chuck having a positioning bush whose end face is perpendicular to the central axis, and the shaft portion of the ceramic rotor is inserted into the inner hole of the positioning bush, and the protruding end face of the back plate is inserted into the inner hole of the positioning bush. The ceramic rotor is held by the three pawls holding the outer peripheral surface of the large-diameter end of the hub portion of the ceramic rotor while in contact with the protruding end surface of the positioning bush. Another feature of the invention is the method of processing the ceramic rotor.

Furthermore, in the present invention, when processing a ceramic rotor according to the method described above, the second processing jig includes (a) a chuck body; Three pieces that are moved toward and away from each other on the surface of the main body facing the ceramic rotor, contact the outer peripheral surface of the large diameter end of the hub portion of the ceramic rotor, and cooperate with each other to grip and hold the ceramic rotor. (c) a positioning hole provided in the center of the surface of the chuck body and opening on the surface of the chuck body;
A three-jaw scroll chuck having a three-jaw scroll chuck, in which a reverse center formed at the protruding end of one shaft of the ceramic rotor is inserted into the positioning hole and supported, and a large diameter side of the hub of the ceramic rotor is supported. Another feature of the present invention is a method of processing a ceramic rotor, in which the ceramic rotor is held by gripping and holding the outer circumferential surface of the end portion by the three claws.

(Examples) Hereinafter, in order to clarify the present invention more specifically, examples of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 schematically shows a ceramic rotor 10 to be subjected to reverse center processing according to the method of the present invention. In this figure, reference numeral 12 denotes a hub section having a substantially truncated cone shape, and as is well known, a plurality of hub sections (some of which are omitted in the figure) are arranged on the outer peripheral surface of the hub section. The blades 14 are integrally formed at predetermined intervals in the circumferential direction.

Further, at the large-diameter end portion (hereinafter referred to as the hub hem) 16 of the hub portion 12, there is a
A disk-shaped back plate 18 having a predetermined thickness is provided coaxially, and a bottom side shaft portion 22 is provided on the protruding end surface of the back plate 18.
On the other hand, a head-side shaft portion 20 that protrudes outward from the end surface of the small-diameter end portion (hereinafter referred to as the hub head) 38 of the hub portion 12 is formed coaxially and outwardly. installed coaxially.

The head side shaft part 20 has a stepped part in the center in the axial direction, and has a first head shaft part 24 and a second head shaft, each having a smaller outer diameter on the distal end side. On the other hand, the hem part side shaft part 22 is provided with two stepped parts at the center in the axial direction, and the outer diameter of the hem part is made smaller toward the tip side. It is composed of a first shaft portion 28, a second hem shaft portion 30, and a first hem shaft portion 32. Further, the protruding tips of the shaft portions 20.22 on both sides are each formed into an inverted center forming portion 25.27 which is previously formed into a substantially conical shape in order to facilitate the grinding process described later.

As is well known, such a ceramic rotor 10 is formed by integrally molding and firing a predetermined ceramic material such as silicon ceramics or cordierite by injection molding or the like.

For such a ceramic rotor IO, in order to balance the rotation and make it into a finished product, it is first necessary to determine its rotational center axis. -1, the reverse center forming portion 25. provided at the tips of the head side and hem side shaft portions 20.22.
27 are respectively polished into a truncated conical shape having a tapered surface at a predetermined angle, and by forming an inverted center rotatably supported by a predetermined center member,
It will be determined as the axis passing through the vertices of these two opposite centers. Further, when forming such a reverse center, the grinding process for both reverse center forming portions 25 and 27 is usually carried out by sliding a grinding tool on the outer peripheral surface of the ceramic rotor 10 while rotating it around the − axis. , will be carried out.

That is, the rotation center axis of the ceramic rotor 10 depends on the position of the top of the reverse center formed on both shaft portions 20.22, in other words, where the rotation axis is set during the grinding process. The axis of rotation of

By the way, when performing such reverse center processing, conventionally, as described above, the head side and hem side shaft portions 20.
22 was held with a chuck or the like, but if the axes of the shaft portions 20 and 22 are used as the rotation axis as they are, the amount of rotational imbalance of the resulting ceramic rotor 10 often becomes extremely large. It was known that

Therefore, first of all, in order to examine the validity of holding the head side and hem side shaft parts 20.22 during reverse center processing, the present inventors conducted manufacturing under the same molding and firing conditions. Regarding the plurality of ceramic rotors 10,
The hub portion 12, which is the rotor main body, of the shaft portions 20 and 22
When we measured the amount of eccentricity for
It was irregular over a wide range of μm. Also, this eccentricity is
It is thought that this is due to the accuracy of the mold and distortion during molding and firing, and therefore, before firing, the shaft portion 20.22 is processed to improve the roundness and eccentricity by grinding etc. It was also confirmed that it could not be removed.

That is, from this, as long as the shaft portions 20 and 22 are used as a reference for determining the rotation axis, it is necessary to correct the deviation using a dial gauge or the like for each fired product as described above. In other words, it has become clear that the shaft portion 20.22 is inappropriate as a reference for determining the center of rotation.

Therefore, the present inventors directly held the rotor body 34 consisting of the hub part 12 and the back plate 18, and determined the ceramic rotor 1 as the axis of the rotor body 34.
After considering the practicality and validity of adopting the zero axis (rotor axis) as the reference for the rotation axis, it was found that in the rotor main body 34, the outer peripheral surface of the hub hem 16 is used as the center reference. In addition, the rotor axis can be determined using the protruding end surface of the back plate 18 as an inclination reference, and by using the rotor axis as a reference for the rotation axis during reverse center processing, the ceramic rotor lO It has been discovered that it is possible to determine the center axis of rotation of the

That is, first, to examine the practicality of using the axis of the rotor body 34 as the rotor axis of the ceramic rotor lo, the rotor axis can be determined by directly holding the rotor body 34. Due to the complicated shape of the rotor main body 34, it is extremely difficult to determine the axis based on only one point, as in the case of holding the shaft. By setting the outer circumferential surface that serves as a center reference and the plane that serves as an inclination reference, it is possible to determine the rotor axis.

Then, the roundness of the outer circumferential surface and the flatness of the axial end face of each part of the rotor body 34 of the ceramic rotor 10 were measured. It has been found that the protruding end surfaces 36 of the back plate 18 are the best, and therefore, with the outer peripheral surface of the hub hem 16 as the center reference, the protruding end surfaces 3 and 3 of the back plate 18 are 6
By employing this as the inclination reference, the rotor axis of the ceramic rotor IO can be advantageously identified.

On the other hand, in order to examine the validity of adopting the rotor axis of the ceramic rotor 10 determined as described above as a reference for determining the rotation axis, several When the ceramic rotor 10 is subjected to double-reverse center processing by grinding while rotating the rotor around the rotor axis, in other words, the rotor axis determined as described above is used as is for the ceramic rotor. When the eccentricity of the obtained ceramic rotor 1o was measured when adopted as the rotation axis of the rotor 10, regularity was observed in the direction of eccentricity, and the eccentricity was also within a relatively small range and a substantially constant value. It was 1ILW to take.

Therefore, the rotor axis of the ceramic rotor 10 determined as described above can be advantageously adopted as a reference for determining the rotation axis, and furthermore, the rotor axis can be directly used as the rotation axis. It is also possible to use it as

In addition, in the ceramic rotor 10 in which double-reversed centers are formed on the head side and bottom side shaft portions 20.22, the double-reverse centers are supported by a predetermined center member, as is well known. At least, by grinding the head side and hem side shaft parts 2o, 22 while rotating around the rotation center axis determined by the bi-reversal center, these shaft parts 2
o, 22 are formed concentrically, and then static and dynamic rotational unbalance around the rotation center axis is measured and adjustment is made based on the measurement results, and furthermore, After that, the head second shaft portion 2 in which the reverse center is formed
6 and the hem portion third shaft portion 32 are respectively cut off at their bases to form a completed product.

Hereinafter, more specific processing procedures for actually performing the above-described reverse center processing will be further explained.

That is, when performing the above-described reverse center processing on the ceramic rotor 10, first, the head side shaft portion 2 is
In order to reverse center the end of the ceramic rotor 10, it is necessary to hold the ceramic rotor 10 rotatably with reference to the outer peripheral surface of the hub hem 16 and the protruding end surface 36 of the back plate 18.

Here, a first chuck 40 as a first processing jig that is preferably used to hold the ceramic rotor 10 is shown in FIGS. 2 and 3.

The first chuck 40 has a basic structure of a so-called three-jaw scroll chuck. Three pawls 46 are disposed so as to be movable in the radial direction toward the center axis of the chuck body.
By rotationally driving through 0, those three claws 4
6 are adapted to be driven toward and away from each other in conjunction with each other. Note that, since the basic structure of the second chuck 40 is well-known, a detailed explanation of its drive mechanism and the like will be omitted.

Each of the claws 46 of the first chuck 40 has a protrusion 52 that projects at a predetermined height in a direction away from the surface 42 of the chuck body 44 at the central axis side end of the chuck body 44. There is.

Furthermore, a protruding pin 54 protruding from the protruding end surface of the protruding portion 52 at a predetermined height in parallel with the central axis of the chuck body 44 is fixedly attached to the protruding portion 52 by a fixing bolt 55. Note that the protruding pins 54 provided on the winter melon 46 are equidistant from each other from the central axis of the chuck body 44, and while maintaining this equidistant positional relationship, the claws 46 can be moved. Accordingly, they are brought closer and further apart from each other.

Further, in the first chuck 40, a positioning bush 5 having a generally cylindrical shape and having a through hole 60 inside is located in the center of the chuck body 44.
8 is integrally attached by screwing its base into the central hole 56 of the chunk body 44.

The positioning bush 58 is positioned such that its tip protrudes from the center of the surface 42 of the chuck body 44 at a predetermined height. Note that the protruding end surface 62 of the positioning bushing 58 is a surface perpendicular to the axis of the bushing, and by coaxially attaching the positioning bushing 58 to the chuck body 44, The tip surface 62 is connected to the chuck body 4
It is arranged perpendicularly to the central axis of 4.

Furthermore, although not shown, the first chuck 40 is attached to a predetermined rotation drive mechanism such as an electric motor, and is driven to rotate around the central axis of the main body.

When holding the ceramic rotor lO with the first chuck 40 having such a structure,
As shown by the two-dot chain line in the figure, the hem side shaft portion 22 of the ceramic rotor 10 is inserted into the through hole 60 of the positioning bushing 5, and the protruding end surface 36 of the back plate 18 is inserted into the through hole 60 of the positioning bushing 5.
is brought into contact with the distal end surface 62 of the positioning bush 58, and the hub hem 1 of the ceramic rotor lO is
This is done by gripping and holding the outer peripheral surfaces of the winter melons 46 and 6 in cooperation with each other using protruding pins 54 provided on the winter melons 46.

That is, by gripping the hub hem 16 with the protruding pin 54, the center of the hub hem 16 is aligned with the central axis of the chuck body 44, and the tip surface 6 of the positioning bush 58 is aligned with the center axis of the chuck body 44.
2, the protruding end surface 3G is held perpendicular to the central axis of the chuck body 44.
The first chuck 4 includes a ceramic rotor 10.
0, the rotor axis is held coaxially with the center axis of the chuck body.

Next, the ceramic rotor 10 held by the first chuck 40 has its head side shaft portion 20
Reverse center processing will be performed on the tip end portion (reverse center forming portion 25). That is, in such reverse center machining, a grindstone 63 that is rotated around the − axis is normally used as shown in FIG. 4, and the ceramic rotor lO The rotor axis: Y, in other words, the rotational axis of the first chuck 40 is positioned inclined by a predetermined angle: α, and the ceramic rotor lO and the grindstone 63 are rotated in opposite directions to each other. At the same time, the inverted center forming portion 25 of the ceramic rotor 10 is subjected to a grinding process.

By such grinding, a conical head-side inverted center whose top portion is located on the rotor axis is formed at the tip of the head-side shaft portion 20 of the ceramic rotor 10.

Furthermore, in the ceramic rotor 10 in which the head-side reverse center is formed in this way, the end of the hem-side shaft portion 22 is then reverse-centered. Then, it is necessary to rotatably hold the ceramic rotor IO again with the end of the hem-side shaft portion 22 protruding outward.

Here, a second chuck 66 as a second processing jig, which is preferably used for holding the ceramic rotor 10, is shown in FIGS. 5 and 6.

This second chuck 66, like the first chuck 40, has a basic structure of a so-called three-jaw scroll chuck, and thus has a similar structure to the first chuck 4o. By assigning the same reference numerals to the members, detailed explanations of their basic structures will be omitted.

That is, in the second chuck 66, the three claws 46 each protrude at a predetermined height in the direction away from the chuck surface 42 at the outer peripheral end of the chuck body 44, and the protruding ends are Further, the chuck body 44 has a substantially U-shaped shape that is bent toward the central axis of the chuck body 44 . Further, on the surface of the claws 46 facing the chuck surface 42, a protruding pin 54 that protrudes at a predetermined height toward the chuck surface 42 in parallel with the central axis of the chuck body 44 is fixedly erected. It is required to be established.

Further, a circular recess 68 is provided in the center of the chuck body 44 of the second chuck 66 of No. 5, 2, and a substantially disc-shaped center receiving member 70 is accommodated therein. This center receiving member 70 is fixedly attached to the chuck body 44 by three bolts 72, and has a positioning hole in the center of its outer surface that has a tapered inner surface that expands in diameter outward. It has 74.

In addition, especially in this embodiment, such a center receiving member 7
0 is inserted into the circular recess 6 by three adjustment screws 75 disposed radially through the inside of the chuck body 44.
The arrangement position within 8 can be adjusted.

The center receiving member 70 has its positioning hole 7
4 is positioned on the central axis of the chuck body 44 and is fixed in a state coaxial with the central axis of the chuck body 44. Further, the taper angle of the positioning hole 74 is set to be the same as the taper angle of the head-side reverse center formed in the head-side shaft portion 2o of the ceramic rotor 10.

Furthermore, like the first chuck 40, the second chuck 66 is also attached to a predetermined rotational drive mechanism (not shown) so that it can be rotated around the center axis of its main body. It has become.

When the ceramic rotor 1o is held by the second chuck 66 having such a structure,
As shown by the two-dot chain line in FIG.
This is done by holding the outer circumferential surface of the bub hem 16 in cooperation with each other with the protruding pins 54 provided on the winter melon 46 while the winter melon 46 is inserted into the bab hem 46.

That is, by gripping the bub hem 16 with the protruding pin 54, the center of the bub hem 16 is aligned, and by inserting it into the positioning hole 74 of the head control center, the top of the head control center is , and is guided onto the central axis of the chuck body 44, where, as is clear from the state in which the ceramic rotor 10 is held against the first chuck 40, the center of the bub hem 16 and the head control center are aligned. The axis connecting the top of the ceramic rotor 10
Since this is the rotor axis, this second chuck 66
Accordingly, when the ceramic rotor 10 is in a state where its rotor axis coincides with the central axis of the chuck body 44,
The second chuck 66 will hold it coaxially.

Therefore, when the ceramic rotor 10 is held by the second chuck 66, the rotor is tilted by a predetermined angle with respect to the rotor axis, similar to the reverse center processing on the head side shaft portion 20. - Using a grindstone that rotates around an axis, while rotating the ceramic rotor 10 and the grindstone in opposite directions,
By applying a grinding process to 7), a conical hem side advancement center is formed at the tip of the hem side shaft portion 22, the top of which is located on the rotor axis.

Therefore, by following the above-described method, a head reversal center and a hem side advancement center are formed well at both ends of the head side shaft portion 20 and the hem side shaft portion 22, respectively, and In particular, in this embodiment, the rotation center axis determined by these two opposite centers is determined based on the rotor axis determined in the rotor main body 34 based on the outer circumferential surface of the bub hem 16 and the protruding end surface of the back plate 18. Then, it can be formed coaxially with the rotor axis.

In the ceramic rotor obtained in this manner, since the rotor axis is determined in the rotor body 34, the amount of rotational unbalance around the rotation center axis determined by the reversible center is determined by the rotor body 34. Therefore, as mentioned above, it is easy to hold such bi-reversed centers with a predetermined center member and to adjust the static and dynamic rotational balance in the ceramic rotor IO. Therefore, the rate of occurrence of defective products can be extremely advantageously reduced.

Furthermore, according to the method described above, the ceramic rotor 1
0 to the first and second chucks 40.66, the extremely troublesome and highly skilled work using a conventional dial gauge etc. is no longer necessary, making the work easier and faster. This means that it is possible to effectively achieve this goal. In this example, by using the method and jig as described above, the time required for reverse center processing was reduced to one-third or less of the time required in the conventional method.

The method for processing a ceramic rotor according to the present invention has been described above in detail by giving specific examples, but these are literal illustrations, and the present invention should not be interpreted in a limited manner only by the above-mentioned specific explanation. It's definitely not something you can do.

For example, in the embodiment described above, the rotor axis of the ceramic rotor 10 determined in the rotor body 34 was directly adopted as the rotation axis, but the rotation axis may be changed depending on the characteristics of the mold. , it may be eccentric in parallel with the rotor axis as a reference.

Further, the shapes of the claws 46 and the protruding pins 54 of the first and second chucks 40.66 can advantageously grip the outer peripheral surface of the bub hem 16 depending on the shape of the wings 14 of the ceramic rotor 10, which is the object to be held. As such, it should be changed as appropriate.

Furthermore, such first and second chunks 40.66
In order to avoid damage to the outer peripheral surface of the hub hem 16 of the ceramic rotor 10 when gripping by the chuck 40,
．． It is also effective to provide a buffering function by providing copper foil or the like on the gripping surface of 66.

In addition, although not listed, the present invention can be implemented in embodiments with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and such embodiments may be modified. It goes without saying that all of these are included within the scope of the present invention as long as they do not depart from the spirit of the present invention.

(Effect of the invention) As is clear from the above explanation, if the method of the present invention is followed,
The rotational axis during reverse center processing of the ceramic rotor can be well determined based on the rotor axis determined as the central axis of the hub portion and the back plate portion, which are the rotor body portions, and thereby the ceramic rotor can be When holding the ceramic rotor in the first and second processing jigs, the conventional work using a dial gauge or the like, which is extremely troublesome and requires a high level of skill, can be omitted, so the ceramic rotor is attached to the processing jigs. This makes it possible to effectively facilitate and speed up the work involved in holding the ceramic rotor, as well as the reverse center processing of the ceramic rotor, thereby advantageously shortening the processing time.

Also, in this way, the rotation axis during reverse center machining,
According to the method of the present invention, which is determined based on the rotor axis determined as the central axis of the rotor body, as in the conventional method,
Compared to the case where the axis of rotation is determined based on the shaft part, the amount of rotational unbalance that occurs in the resulting processed product can be suppressed to a small extent, reducing the incidence of defective products and improving the rotational balance. This makes it easier to adjust.

Furthermore, by using, as the first processing jig, a three-jaw scroll chuck equipped with a positioning bush that abuts against the back plate of the ceramic rotor, the ceramic rotor can be chucked so that its rotor shaft is in the chuck. It can be advantageously and easily held in a state that coincides with the central axis of the main body.

Furthermore, by using, as the second processing jig, a three-jaw scroll chuck equipped with a positioning hole into which the reverse center formed on one shaft of the ceramic rotor is inserted, the ceramic rotor can be The chuck can be advantageously and easily held in a state where the axis coincides with the central axis of the chuck body.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing a fired product of a ceramic rotor, which is a workpiece to be subjected to the method of the present invention. Also,
FIG. 2 is a front view showing the first chuck suitably used in the method of the present invention, and FIG. 3 is a cross-sectional view taken along the line ■-■ in FIG. Further, FIG. 4 is a schematic explanatory diagram for explaining a grinding operation when performing reverse center processing on the ceramic rotor shown in FIG. 1. Furthermore, FIG. 5 is a front view showing the second chuck suitably used in the method of the present invention, and FIG.
The figure is a sectional view taken along line Vl-Vl in FIG. 10: Ceramic rotor 12: Hub part 16: Hub hem 20: Head side shaft part 34: Rotor body part 38: Hub head 42: Surface 46: Pawl 50: Pinion 58: Positioning bush 62: Tip surface 70: Center holder Element. 14: Wings 18: Back plate 22: Bottom side shaft 36: Projecting end surface 40: First chuck 44: Chuck body 48 Niss roll 54: Projecting pin 60: Through hole 66: Second chuck 74: Positioning hole

Claims (3)

[Claims] (1) A substantially truncated conical hub portion of a turbocharger rotor, gas turbine, etc., which has a plurality of blades on its outer circumferential surface;
A disc-shaped back plate of a predetermined thickness coaxially protruding from the large diameter side end face of the hub part, and coaxially outward from the small diameter side end face of the hub part and the protruding end face of the back plate, respectively. A ceramic rotor integrally molded and fired using a predetermined ceramic material and having a protruding shaft portion,
When performing reverse center processing on the protruding ends of both shaft parts, the outer circumferential surface of the large-diameter end of the hub part is used as the center reference of the rotor shaft, and the protruding end surface of the back plate is used as the tilt reference of the rotor shaft. The ceramic rotor is held in a predetermined first processing jig, and one protruding end of the shaft is ground to form a conical inverted center, and then the ceramic rotor is is held in a predetermined second machining jig with reference to the reverse center formed on the one shaft portion and the outer circumferential surface of the large diameter end of the hub portion, and the other shaft of the ceramic rotor is A method of processing a ceramic rotor, the method comprising: forming a conical inverted center by grinding the protruding end of the rotor. (2) The first processing jig is moved toward and away from the chuck body in conjunction with the surface of the chuck body facing the ceramic rotor toward the central axis of the chuck body. three claws that contact the outer peripheral surface of the large-diameter end of the hub portion of the ceramic rotor and cooperate with each other to grip; and three claws located in the center of the surface of the chuck body that a positioning bush that protrudes upward at a predetermined height and has an inner hole that is open at least at the protruding side end face, and the protruding side end face is an end face perpendicular to the central axis of the chuck body; The jaw scroll chuck is a jaw scroll chuck, and the shaft portion of the ceramic rotor is inserted into the inner hole of the positioning bush, and the protruding end surface of the back plate is brought into contact with the protruding end surface of the positioning bush. Claim 1: The ceramic rotor is held by the three claws gripping the outer peripheral surface of the large-diameter end of the hub portion of the ceramic rotor.
) Machining method of ceramic rotor described. (3) The second processing jig is moved toward and away from the chuck body in conjunction with the surface of the chuck body facing the ceramic rotor toward the central axis of the chuck body. three claws that come into contact with the outer circumferential surface of the large-diameter end of the hub portion of the ceramic rotor and cooperate with each other to grip it; and a surface of the chuck body that is provided at the center of the surface of the chuck body. A three-jaw scroll chuck has a positioning hole that opens upward, and a reverse center formed at the protruding end of one shaft of the ceramic rotor is inserted into the positioning hole to be supported, and the ceramic rotor Processing of a ceramic rotor according to claim 1 or 2, wherein the ceramic rotor is held by gripping the outer circumferential surface of the large-diameter end of the hub portion with the three claws. Method.