JPS6026197A - Turbo machine and blade wheel chip - Google Patents

Abstract

PURPOSE:To obtain a large centrifugal fan easy to mold and sinter while not subject to defect, by forming a blade wheel through combination of ceramic blade wheel chip and shaft. CONSTITUTION:In order to combine a ceramic shaft 10, blade wheel 20 and blade wheel stopper 30, a plurality of ceramic blade wheel chips 24 splitted radially are first combined to produce a blade wheel 20 then the flange 11 of the shaft 10 is contacted against a notch section having reduced thickness while provided near the shaft 10 of the blade wheel chip 24 and the shaft 10 is fitted. Thereafter, the shaft 10 is inserted into a hole of an inward flange 31 of the blade wheel stopper 30 and the cylindrical section 21 of the blade wheel 20 is fitted to the blade wheel stopper 30. Consequently, a large centrifugal fan having a ceramic blade wheel 20 can be produced through mass production of small blade wheel chips resulting in facilitation of molding and sintering without defect.

Description

[Detailed description of the invention] About machines.

Taking a centrifugal fan, which is a type of turbomachinery, as an example, centrifugal fans often have to handle high-temperature or high-temperature and corrosive gases, and research into heat-resistant and corrosion-resistant materials is being actively conducted. ing. However, metal materials have extremely limited heat resistance or high temperature corrosion resistance. recently,
Ceramic materials such as silicon carbide and silicon nitride with excellent properties have been developed, and centrifugal fans using these materials are attracting attention.

Ceramics have excellent heat resistance and corrosion resistance, but their toughness and
Since workability is inferior to metal, in centrifugal fans that handle high-temperature gas, only the part that comes into contact with the high-temperature gas is made of a ceramic ring, the other parts are made of metal, and the two are joined together. In a centrifugal fan, the impeller and shaft are exposed to high temperatures, so it is desirable to make them of ceramics.

On the other hand, extrusion molding, press molding, injection molding, or casting molding methods are generally used to form ceramic parts, but complex molding methods such as impellers, especially centrifugal fan impellers, etc. are generally used. Extrusion molding is not suitable for molding shaped members, and press molding requires processing, which is unsuitable for mass production. Therefore, injection molding or casting molding is used to mold products with complex shapes such as impellers. However, when attempting to make larger molded products, the injection molding method has equipment limitations such as the need to increase the size of the injection molding machine, and there are also internal defects due to the fluidity of the polymer-powder system. There are problems such as easy to cause.

Furthermore, the casting method has problems in forming thick parts.

As mentioned above, if the contact part with the high-temperature gas is made of ceramic ring, in the case of a centrifugal fan, the entire impeller along with the shaft must be molded from ceramics, which requires large and complicated parts. In addition to the problem of having to be molded, increasing the size of this centrifugal fan also increases the size of the impeller, making it even more difficult to solve the above-mentioned problems.

These problems are the same in centrifugal turbo driven machines such as centrifugal blowers and centrifugal compressors, or centrifugal turbo prime movers such as centrifugal turbines. Also, axial flow
, mixed-flow type turbomachinery suffers from similar problems to varying degrees.

The purpose of the present invention is to fully demonstrate the characteristics of ceramics without having to mold the ceramic members that make up the structure even when the size is increased, and to have a large-sized To provide a turbomachine having a ceramic blade wheel, which can be used under high temperature conditions, and a blade wheel piece therefor.

The turbomachine of the present invention has a blade wheel retainer having a cylindrical body, a blade wheel piece having a ceramic ring, and a shaft having a ceramic ring, the shaft having a flange, and the blade wheel piece having a cylindrical portion. is divided radially into a plurality of pieces, and the blade wheel pieces are combined to form the blade wheel, and the shaft is fitted to the blade wheel and butted against the flange, and the cylindrical part is attached to the blade wheel holder. The blade wheel of the present invention has a shape in which the blade wheel is divided radially into a plurality of pieces. This is a ceramic ring blade wheel piece for turbo machinery.

In a preferred embodiment of the turbomachine of the present invention, the flange surface of the shaft is inclined obliquely toward the impeller contact side, the flange contact surface of the impeller is obliquely inclined corresponding to the flange surface, and the other In a preferred embodiment, the shaft portion of the shaft closer to the flange and the flange surface closer to the shaft portion form an arc with a continuous cross section. In another preferred embodiment of the turbomachine of the present invention, the wheel retainer has an outward flange correspondingly abutting the rear surface of the blade wheel, and in yet another preferred embodiment, the wheel retainer has an inward flange. In yet another preferred embodiment of the present invention, the impeller presser is pressed against the flange side by the impeller presser.

In a preferred embodiment of the blade wheel piece of the present invention, the blade wheel piece is integrally molded.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A turbomachine and a blade wheel piece according to the present invention will be described in detail below with reference to the drawings, taking a centrifugal fan as an example as an example.

The centrifugal fan whose main parts are shown in FIG. 2 includes a ceramic shaft 10, a ceramic impeller 20, and a impeller holder 3.
It has 0.

The shaft 10 has a flange 11. Figure 2C is an example of a cantilever type centrifugal fan, so the flange 11 is provided at the tip of the shaft 10, but in the case of a double-sided type, etc., the flange does not necessarily have to be located at the tip of the shaft. do not.

The impeller 20 consists of a cylindrical portion 21, a main plate 22, and blades 23. The main plate 22 is a portion that typically occupies the main projected area in a front view of the centrifugal impeller as seen from the wing side, and
In a cross section parallel to the axis of the blade wheel, the blade side line of the main plate 22 is typically parallel to the axis or at a small angle with the axis near the axis, and increases at an angle with the axis as it moves away from the axis. This main plate 22 has the function of holding and fixing the blades at a required interval in the impeller, and also has the function of converting the direction of movement of the fluid flowing in parallel to the axis into the radial direction. Note that the main plate 22 may extend to the outermost edge of the wing, or may not extend to the outermost edge of the wing.

The blades 23 are typically erected on the main plate 22 approximately parallel to the axis, and are typically provided along the radius.
There is one. However, it may also form an angle with the axis or may form an angle with the radius. The blade 23 mainly has the function of mutually converting the energy of the fluid and the rotational energy of the blade wheel.

The cylindrical portion is typically provided so as to protrude from the back side of the main plate 22 and surround the shaft.

The blade wheel 20 is formed by combining a plurality of blade wheel pieces 24, for example, 10 pieces, as shown in FIGS. 1(a) and 1'Cb). The blade wheel pieces 24 have a shape in which the blade wheel 20 is radially divided into radial sections. Increasing the number of divisions as much as possible will make each blade wheel smaller and easier to form, and will improve the quality of the blade wheel, but the number of divisions may be smaller in terms of the strength and stability of the combined blade wheel. desirable. Therefore, as the impeller becomes larger, the number of divisions increases, and the number of divisions is usually preferably about 5 to 18. It is preferable that each blade wheel piece 24 has the same shape, but for example, a blade wheel piece with blades 25 and a blade wheel piece without blades may be combined, so that they are not mutually the same shape. Good too. In the case where each blade wheel piece 24 has a cylindrical portion 21, a main plate 22, and blades 23, the number of blades for each blade wheel month is derived by taking into account the number of blades of the entire blade wheel and the number of divisions, It is usually preferable to have one to three blades, particularly one blade, but it is desirable that one blade does not span multiple blade wheels. Also, as shown in Figure 1(c),
For example, it is preferable to provide the notch 25 in a portion of the blade wheel near the shaft to reduce the thick part of the blade wheel because it facilitates molding and sintering of the blade wheel. The flanges may be able to butt against each other. In addition, in cases where the blade is not curved in a radius but is curved in a spiral shape, for example, the blade wheel may be divided into shapes using such spiral lines, and such divisions may also be used. This is included in the concept of "radially dividing" in the present invention.

In FIG. 2, the impeller holder 30 has an inward flange 5 at the end.
It is preferably made of mashikuke ceramics.

To combine the shaft 10, the blade wheel 20, and the blade wheel retainer 30, first combine the blade wheel pieces 24 to form the blade wheel 20, and then bring the flange 11 of the shaft 10 into contact with this. Insert. Next, the shaft 10 is inserted into the hole of the inward flange 31 of the blade wheel holder 30, and the blade wheel 2 is inserted into the blade wheel holder 50.
Insert the cylindrical portion 21 of 17. The other end of the shaft 10 is shrink-fitted to the metal shaft 1 in the embodiment shown in FIG.

Generally, shaft 10 is preferably joined to a metal shaft by any suitable means.

In the embodiment shown in FIG. 2, the spacer 41 is made of ceramic or the like.
, a spacer washer 42, a spring such as a disc spring 45, a metal cylinder 44, a nut washer 45, a nut 46, etc. The impeller holder 60 is pressed 17 toward the flange side by the impeller holder 40. . In assembling these members, the blade wheel 20 combined with the blade wheel pieces 24 is attached to the shaft 1.
0 to abut against the flange 11, and then the cylindrical portion 21 of the impeller 20 is fitted into the impeller holder 60. Next, the shaft 10 is fitted into the spacer 41, the spacer washer 42, and the disc spring 43. Here, it is preferable that the inner diameter of each of the spacer 41, spacer washer 42, and disc spring 43 be slightly larger than the outer diameter of the shaft 10 to facilitate positioning. Next, the shaft 10 is joined to the metal shaft 1 by an appropriate means. In the case of joining by shrink fitting as in this embodiment, an adapter prepared to match the flange 11 is used. The shaft 10 fitted in the impeller 20 etc. is fixed vertically with the joint part with the metal shaft 1 facing upward, and the metal shaft 1 heated to an appropriate temperature is inserted into the shaft 1 from vertically above.
0 and perform a shrink fit. Next, a metal cylinder 44,
By inserting the nut washer 45 and the nut 46 from the other end of the metal shaft 1 and tightening the nut 46, the disc spring 4
6 and press the impeller holder 30 to fix the impeller 20.

The impeller is thus fixed to the shaft 10, the shaft 10 is joined to the metal shaft 1, and the metal shaft 1 is connected to the power section. It goes without saying that the impeller pusher means 40 is not limited to the configuration described above.

In the example of FIG. 2, the wheel retainer 30 has its inward flange 31
is pressed by the spacer 41, and the end surface of the blade wheel retainer 30 closer to the flange 11 comes into contact with the back surface of the blade wheel main plate, thereby pressing and fixing the blade wheel toward the flange. At the same time, since the cylindrical portion 21 of the blade wheel is fitted into the blade wheel retainer 30, when the blade wheel rotates, the blade wheel will fly outward due to centrifugal force. Note that when fitting the cylindrical portion 21 of the blade wheel to the blade wheel retainer 31, an appropriate heat-resistant cushioning material or the like may be interposed in the fitting portion. Further, the inward flange 31 of the impeller holder 30 may be in contact with the end surface of the cylindrical portion of the impeller, and in place of the above-mentioned impeller holder pressing means, the hole diameter of the inward flange 61 may be replaced with the shaft diameter. Similarly, the male thread provided on the shaft and the female thread provided on the hole surface of the inward flange may be screwed together, and the blade wheel piece may be fixed to the shaft with a blade wheel retainer. Thus, having an inwardly directed flange has the advantage of being able to adopt the configuration described above.

Moreover, instead of the shape shown in FIG. 3(a), the blade wheel retainer 60 may have an outward flange 32 corresponding to and abutting on the rear surface of the blade wheel, as shown in FIG. 3(b). In this case, compared to the case with outward flanges, the area in contact with the back surface of the impeller is larger, which averages out the load acting on the back surface of the impeller and increases the frictional force, thus preventing breakage. It has the effect of preventing rotational force and transmitting rotational force well.

Note that it is not essential that the impeller holder 50 has an inward flange and an outward flange, and may be a cylindrical body having equal inner diameters and equal outer diameters, for example.

Furthermore, the cylindrical portion of the impeller is made into a conical tube shape by combining the blade wheel pieces as shown in FIG. 1(C), and the diameter of the impeller is reduced at the end. When the conical cylindrical retaining surface comes into contact with the impeller, rotational force can be transmitted through this retaining surface, and a component of the pressing force acts in the axial direction, causing the rotary force to act on the impeller. This has the effect of preventing one side from popping out 7.

The flange 11 of the shaft 10 is not limited to a thin tube as long as it has a structure that can lock the blade wheel piece in the axial direction, but it can be used to easily prevent the blade wheel piece from flying outward due to centrifugal force when the blade wheel rotates. As shown in FIG. 2, the flange surface is inclined toward the impeller contact side, and it is desirable that the flange contact surface of the impeller be inclined correspondingly to the flange surface.

The flange-side shaft portion of the shaft may be provided at an angle with respect to the shaft-side flange surface, but as shown in FIG. It is preferable that an arc with a continuous cross section be formed entirely at an angle υ with respect to the plane. When the blade wheel comes into contact with the flange surface, stress is applied to the base of the flange surface.
By clearly connecting these parts, stress concentration can be avoided. Although the hollow portion 13 is present in FIG. 2, the hollow portion may be omitted by making the blade wheel piece have a shape corresponding to the flange abutment shaft portion 14.

The ceramics constituting the blade wheel pieces and the shaft are not particularly limited, but silicon nitride, silicon carbide, zirconia, alumina, etc. can be preferably used. Further, the blade wheel piece and the shaft may be made of different ceramics, but it is preferable that they be made of the same material so as not to cause a difference in thermal expansion.

Although the impeller holder 30 may be made of a solid material such as metal, it is preferably made of ceramics, especially the above-mentioned ceramics, in order to reduce or eliminate the difference in thermal expansion. The spacer may also be made of metal, but is preferably made of ceramic, and is particularly preferably made of highly heat-insulating ceramic, such as cordierite.

As detailed above, the blade wheel piece of the present invention is used to form a small blade wheel instead of integrally molding a large blade wheel in order to obtain a large centrifugal fan having a ceramic blade wheel. There are advantages to doing so. These blade wheels are easy to mold and sinter, and defects are unlikely to occur during molding and sintering.If defects are still found or if they are damaged during operation, only that blade wheel can be removed. All you have to do is replace it, and the replacement is easy. Furthermore, in order to obtain a blade wheel having a large number of blades, it is sufficient to prepare one type or a small number of types of simple-shaped blade wheel pieces having the same shape as each other, thereby improving mass production efficiency. However, it is preferable that the wing east piece of the present invention has a cylindrical part or does not include a shaft so that the above-mentioned assembly method can be adopted. Any suitable method of assembly is possible, and therefore the blade wheel may be a wheel piece that includes a shaft or a wheel piece that does not have a cylindrical part. Further, it is preferable that the blade wheel pieces be integrally molded by an injection molding method, a cast molding method, or the like, since this improves productivity, but it is not necessarily necessary to be integrally molded.

In addition, the centrifugal fan of the present invention is not only useful because it can employ blade wheels having the above-mentioned advantages, but also has excellent heat resistance and corrosion resistance. It also has the effect of making it function as a.

Note that although the above description has mainly been given to centrifugal fans, the present invention can also be applied to other centrifugal turbomachines such as centrifugal blowers, centrifugal compressors, and centrifugal turbines. Although the present invention is particularly suitable for centrifugal turbomachines and blade wheels therefor, it is also applicable to mixed-flow or axial-flow turbomachines and blade wheels therefor.

[Brief explanation of drawings]

FIG. 1 is a front view (a) and a sectional view (b) of an embodiment of a blade wheel piece of the present invention, and a sectional view (c) of another embodiment. - FIG. 2 is an upper half sectional view of the main part of a centrifugal fan which is an embodiment of the turbomachine of the present invention. Figure 5 (a), (b)
) and (C) are sectional views of different embodiments of the impeller holder used in the turbomachine of the present invention. 10: Shaft 11: Flange 20:,! R wheel 21: Cylindrical part 22: Main plate 23: Wing 24: Blade wheel piece 30: Wheel holder 31: Inward flange 52 = Outward flange f) (αn (λ4) 1 i3 shoulder -566- <C-)

Claims (1)

[Scope of Claims] 1. A blade wheel holder having a cylindrical body, a blade wheel piece made of ceramics, and a shaft made of ceramics. The blade wheel is divided radially into a plurality of pieces, and the blade wheel pieces are combined to form the blade wheel, and the shaft is fitted to the blade wheel and butted against the flange, and the blade wheel is pressed against the blade wheel holder. A turbomachine characterized in that the cylindrical portion is fitted and the blade wheel piece is fixed to the shaft by the blade wheel retainer. 2. The turbo according to claim 1, wherein the flange surface of the shaft is not obliquely inclined toward the impeller contact side, and the flange contact surface of the impeller is obliquely inclined corresponding to the flange surface. machine. 3. The turbomachine according to claim 1 or 2, wherein the flange protrusion shaft portion of the shaft and the shaft protrusion flange surface form a continuous arc in cross section. 4. The turbomachine according to any one of claims 1 to 3, wherein the blade wheel retainer has an outward flange that corresponds to and contacts the rear surface of the blade wheel. 5. The turbomachine according to any one of claims 1 to 4, wherein the impeller holder has an inward flange. 6. The turbomachine according to any one of claims 1 to 5, wherein the impeller presser is pressed toward the flange by a impeller presser suppressing means. 7. Ceramic blade wheel pieces for turbomachinery, which have a shape in which the blade wheel is divided radially into multiple pieces. 8. The blade wheel piece according to claim 7, wherein the blade wheel piece is integrally molded.