JPS595805A - Axial flow turbine rotor - Google Patents

Abstract

PURPOSE:To freely predetermined a proper pitch-chord ratio, by engaging a ceramic turbine blade into an annular recess from the axial opening of metallic rotor disk and then feeding the blade in a peripheral direction. CONSTITUTION:The rim section 15 of ceramic segment 13 constituting a turbine blade is engaged with an annular recess 16 from the opening of metallic rotor disk and then feeding the blade progressively in a peripheral direction. Thereafter, an opening lid 18 is provided on the opening 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an axial flow turbine rotor, and more particularly to an axial flow turbine rotor constructed of ceramic rotor blades and metal disks.

In recent years, research has been progressing on the application of ceramics, which have high-temperature strength characteristics, to zeta-biturine rotors, and examples of axial flow turbine rotors include, for example, U.S. Pat.
There are known rotors in which the entire rotor is made of ceramics, as disclosed in No.

FIG. 1 shows an example of a trickle turbine rotor made of a combination of ceramic blades and a metal disk published in the Journal of the American Society of Mechanical Engineers, where l is the turbine rotor, C is the ceramic blade, and 3 is the metal rotor. It's a disc.

In this example, each of the ceramic blades is separated and arranged as a segment of the same shape, and adjacent ceramic blades are connected to their rims at a portion jA near the middle of the inter-blade flow path l. Comrades are structured to maintain contact.

This example is shown as viewed from the gas inflow side, where t is the wing of the ceramic wing, 7 is a dovetail provided from the rim j of the ceramic R- to the disk 3 side on the back surface; 2A and 2B are the leading and trailing edges of wing 2. r is a dovetail fitting groove carved at the mounting position corresponding to each blade in the metal rotor disk 3, and as shown in Figure 1, the tapered surface rA on the picture side of the fitting groove is the dovetail 7. The tapered surface rA and the wedge surface 7A are formed to be slightly wider toward each other, and a cushioning material is interposed between the tapered surface rA and the wedge surface 7A as shown in FIG. This prevents compressive stress from occurring in the ceramic blades due to thermal expansion of the disk 3 during operation of the rotor.

However, in such a conventional axial flow turbine quadrant, the dovetail portions 7 of the individual ceramics R,2
Since the rotor is fitted into the fitting groove L of the metal roller disk 3 to form an integrated rotor/entire structure, the following problems arise.

/) Both the molding process and the processing process are complicated, and precision is required for a large number of individual ceramics R, 2, and the number of fitting grooves t corresponding to the number of these ceramic wings 2 is Nv. The manufacturing process for the metal rotor disk 3 that needs to be completed increases the cost.

e) In the rotor disk 3, a model fitting groove t corresponding to the shape of the dovetail 7 is provided for each position for mounting the container 2, so in this case, the bottoms of the adjacent fitting grooves are constricted. Since it is necessary to ensure the circumferential thickness of the remaining neck lσ for strength, the pitch P between the blades λ is limited, and the pitch P between the blades λ exceeds the appropriate value in terms of aerodynamic performance. Pitch/code ratio cannot be selected.

In view of these conventional problems, an object of the present invention is to provide a shaft that can reduce costs by simplifying the machining and assembly process, and that can be made into a ceramic blade having an appropriate pitch P and chord ratio. An object of the present invention is to provide a flow turbine rotor.

In order to achieve this object, in the present invention, a turbine blade is formed by connecting ceramic segments of the same type in the circumferential direction, each consisting of one or more blade parts and a rim part. In the metal rotor disk, an annular groove is formed in which the rim portion of each segment fits in both the radial and circumferential directions, and a portion of the groove is cut out in the circumferential direction, so that each segment can be separated from the axial direction. An opening is provided for low insertion into the groove, and the segments are fitted one after another through this opening and fed in circumferentially while remaining fitted, and the last segment is installed and the opening is closed with a metal lid. Configure it to do so.

The present invention will be described in detail below based on the drawings.〇 Figure 3 shows an embodiment of the present invention, where // is a turbine rotor, /2 is a metal rotor disk, and 13 is a turbine 8. This is the ceramic segment that makes up the In this example, one segment /3 has q wing parts /4' and a common rim part /S, and the fourth segment has a shape as shown in the figure. That is, the circumferential end surface ljA of the rim portion /j is formed to be in the radial direction of the rotor l/, and the angle α0 formed between the end surfaces /jA is a value obtained by dividing 3600 into several equal parts. In FIG. 3, such a segment 13
are shown being assembled one after another into the rotor disk /2, where /6 is the outer circumferential surface of the disk 12 /λA
An annular groove is carved along the annular groove, /7 is an opening made by cutting out a part of this annular groove /B to match the side shape of the rim part /S of segment /3, and 1g is an opening that closes this opening /7. It is an opening lid for Note that by making the angle β0 formed by the opening 17 and the circumferential end of the opening lid n somewhat larger than the angle α0 formed by the end surface ljA of the rim portion /S described above, the groove of segment)/3 is formed. 16 can be made easier.

Figure 5 shows the state in which the rim part /j is fitted into the groove /6, and in this way both shoulder surfaces /3B and groove /6 of the rim part /j are fitted.
A cushioning material 19 made of a heat-resistant material such as ceramic fiber is inserted between this shoulder surface of B and the surface facing B. Note that the cross-sectional shape of the groove /B is the same as that shown in FIG. 5 when the opening cover /g is attached to the disk /2 except for the part where the opening /7 is provided.

Furthermore, as shown in FIG. 6, a cushioning material 19 is interposed between the end surfaces /jA of adjacent segments /3, and the bottom surface of the groove 76 and the rim end surface nA of the bottom surface /4A abut against each other. At least one of the positions corresponding to the parts is provided with a protruding retaining protrusion as shown in this figure, and on the other hand, a protrusion is also provided at each end of the end face/SA corresponding to the position of this protrusion. Four parts 2t are formed according to the shape. That is, by engaging such a protrusion with the recess 2/ of the rim part /S, each of the seven rings and the mento /3 is prohibited from moving in the circumferential direction along the groove l≦.

Note that the cross-sectional shapes of the protrusion and the four parts λl are preferably smooth, for example, arcuate, to avoid stress concentration.

The axial flow turbine rotor constructed in this way has an odor element (81
C), it can be formed by a molding method such as injection molding or slip casting using a ceramic material such as silicon nitride (8iN4). The thus formed segments /3 are fitted into the rotor disk /2 one after another from the opening m/7 along the annular groove /6, and the rim portion /! A buffer material /9 is interposed between the shoulder surface /K B and the groove 76 and between the abutment surface ljA of the rim /j, and the segment /3 at the opening /7 is inserted. Finally, after fitting, the opening cover /g is attached to the opening /7, and its welded surfaces are welded and joined by, for example, electron beam welding.

In the above description, a case has been described in which a plurality of wing parts /4I are provided in segment /3, but the number of wing parts /4I may be seven. However, the greater the number of blade parts /41 provided in the seven segments /3, the simpler the molding of the segments /3 and the processing and assembly process as the rotor //. Accordingly, although not shown, in one embodiment of the present invention, a segment may be integrally formed with a wing extending over its entire circumference, and if necessary, a slit may be provided at one location on the rim to release thermal stress. When forming the rim and wing portion in this way, an opening is provided around the entire circumference of the groove of the quadruple disk into which the rim is fitted, and the opening lid that is fitted and welded to this opening is also ring-shaped. to form. Furthermore, it goes without saying that the segment )/3 may be divided into thirds or thirds of the entire circumference in the same manner.

As explained above, according to the present invention, one or more wing portions and a rim portion for arranging the wing portions around a disk are molded from ceramic as an integral segment. The rim portion of the same-shaped segment formed in this manner is inserted into the opening of the annular groove provided along the outer circumferential surface of the metal rotor disk to engage with the groove, and the opening cover is attached to the opening to remove the rotor disk. This structure simplifies the manufacturing process and reduces costs. It also eliminates the need to provide dovetail grooves for each blade in the rotor disk as in the past, so the pitch P between the blades can be reduced. As a result, there are no restrictions and an appropriate pitch/code ratio can be set freely, thereby improving aerodynamic performance.

Furthermore, if the wing portion and the rim portion covering the entire circumference are made into one cell, the manufacturing process can be further simplified and the cost can be further reduced.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an example of a conventional axial flow turbine rotor consisting of a combination of ceramic blades and a metal rotor disk, Fig. 1 is an enlarged view of the blade attachment section, and Fig. 3 is an axial flow turbine rotor according to the present invention. A configuration diagram showing an example of a turbine rotor, FIG. 1 is a configuration diagram of the ceramic segment, and FIG. 3 is A in FIG.
-A partial sectional view, and FIG. 6 is a BB line sectional view of FIG. /, l/... Turbine quarter, 2... Ceramic A, , 2A... Leading edge, 2B... Trailing edge, 3... Rotor disk, G... Inter-blade flow path , ! ...Rim part, 3k...Part, 6...Wing part, 7
...Dovetail, 7A...side surface! ...fitting groove,
A...Tapered surface, W...Buffer side,
lθ...Neck, 12...Rotor disk, 7
2 people...Outer circumferential surface, /3...Ceramics segment, /G...wing part, /! ;...Rim part, /SA...End face, /3B...Shoulder surface, /l...Annular groove, /7...Opening part, 7g...Opening lid,
/9...Buffer side,〃...Protrusion,
2/...four parts. Patent applicant Nissan Motor Co., Ltd.

Claims (1)

[Claims] /) An axial flow turbine rotor in which ceramic blades are attached to a metal rotor disk, including at least one blade and a mechanism for arranging the blade around the outer peripheral surface of the rotor disk. The rim portion is formed of ceramic as an integral segment, and an annular groove is provided on the outer peripheral surface of the rotor disk to engage the rim portion of the segment in the radial direction of the rotor disk over the entire circumference, and at least one of the annular grooves An opening into which the rim part can be fitted is formed in a part of the blade, and the rim part is fitted into the annular groove via a cushioning material through the opening, thereby arranging the blades on the rotor disk. An axial flow turbine rotor characterized by having a closed opening. h) In the axial flow turbine quaternary according to claim 1, the annular groove is provided with a locking protrusion that prevents movement of the rim portion in the circumferential direction at least at one location. turbine rotor.