JP2010119264A - Rotor for compact gas turbine generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor for a compact gas turbine generator having an excellent rotational balance at high-speed rotation. <P>SOLUTION: The rotor 100 for the compact gas turbine generator includes a turbine-compressor 4 integrally forming a turbine 1 made of ceramics, a compressor 2 mutually facing a rear 2a to the rear 1a of the turbine, being joined with the turbine 1 so as to have the same shaft and being made of ceramics, and a connecting shaft 3 being extended from the center of the compressor 2, having the same shaft as the turbine 1 and the compressor 2 and being made of ceramics. The rotor for the compact gas turbine generator further includes a shaft 15 including a magnet incorporating part 13 detachably connecting an end to the connecting shaft 3 so as to have the same shaft as the connecting shaft 3 for the turbine-compressor 4 and being capable of incorporating a permanent magnet 12 and bearings 14 in at least two places. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotor for a small gas turbine generator, and more particularly to a rotor for a small gas turbine generator that has an excellent rotational balance during high-speed rotation.

  In recent years, an ultra-compact gas turbine generator that generates an electric output of 1 kW or less has been expected as a power source that is small, light, and capable of operating for a long time. The rotor used in such a micro gas turbine has a structure including a turbine portion and a compressor portion having a blade portion diameter of about 10 to 30 mm, and a shaft portion having a diameter of 10 mm or less (about 3 mm to 7 mm). Yes, it is operated at ultra high speed rotation (several hundred thousand rpm). Such an ultra-high-speed rotating rotor needs to adjust the rotational balance with high accuracy. In particular, it is important to ensure concentricity between the turbine section, the compressor section, and the shaft section.

Therefore, for example, a small-sized gas turbine for power generation in which a turbine portion, a compressor portion, and a shaft portion are integrally formed has been proposed (for example, see Patent Document 1).
JP-T-2006-504902

  In the power generation small gas turbine rotor described in Patent Document 1, since the turbine part, the compressor part, and the shaft part are integrally formed, it is necessary to correct the rotation balance at the time of production as the whole power generation small gas turbine rotor. was there. Therefore, it is not always easy to correct the rotation balance.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a rotor for a small gas turbine generator having an excellent rotational balance during high-speed rotation.

  In order to solve the above-described problems, the present invention provides the following rotor for a small gas turbine generator.

[1] A ceramic turbine section, a ceramic compressor section joined to the turbine section so that the rear surface faces and is coaxial with the rear surface of the turbine section, and the turbine section extends from the center of the compressor section And a coupling shaft portion made of ceramic that is coaxial with the compressor portion, and a turbine-compressor portion formed integrally with the coupling shaft portion so as to be coaxial with the coupling shaft portion of the turbine-compressor portion. The rotor for small gas turbine generators provided with the magnet built-in part which can incorporate a permanent magnet, and the axial part which has a bearing part of at least two places where the edge part was connected so that attachment or detachment was possible.

[2] The shaft portion has one of the bearing portions between the magnet built-in portion and the end portion to which the coupling shaft portion of the turbine-compressor portion is coupled, The rotor for a small gas turbine generator according to [1], wherein a diameter of a cross section orthogonal to one central axis direction is equal to or less than a diameter of a cross section orthogonal to the central axis direction of the magnet built-in portion.

[3] The small gas turbine according to [1] or [2], wherein a method of connecting the turbine-compressor unit and the shaft unit is screw fastening, and the screw fastening is self-tightening in a rotation direction. Rotor for generator.

  According to the rotor for a small gas turbine generator of the present invention, since the turbine-compressor and the shaft are detachably coupled, the rotational balance between the turbine-compressor and the shaft is separately corrected during production. This makes it possible to obtain a more accurate rotational balance.

  Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiments, and is within the scope of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge of those skilled in the art.

1. Small gas turbine generator rotor:
One embodiment of a rotor for a small gas turbine generator according to the present invention includes a turbine portion 1 made of ceramic, and a turbine portion 1 such that the back face faces the rear face of the ceramic portion 1 and is coaxial with the back face of the turbine portion 1. A turbine-compressor unit formed by integrally forming a ceramic compressor unit 2 joined to each other and a ceramic coupling shaft unit 3 extending from the center of the compressor unit 2 and coaxial with the turbine unit 1 and the compressor unit 2 4, and further, a shaft portion 15 having an end portion 11 detachably coupled to the coupling shaft portion 3 so as to be coaxial with the coupling shaft portion 3 of the turbine-compressor portion 4. The shaft portion 15 has a magnet built-in portion 13 in which the permanent magnet 12 can be built in and two bearing portions 14, 14. The bearing portion 14 is formed in at least two places on the shaft portion 15 and may be three or more places. FIG. 1 is a side view schematically showing one embodiment of a rotor for a small gas turbine generator of the present invention.

  A rotor for a small gas turbine generator that rotates at a rotational speed (operating rotational speed) of 500,000 rpm (rotation / minute) or more needs to correct the rotational balance with extremely high accuracy. The main causes of unbalance in rotational balance include “shape error” of the turbine-compressor portion having a complicated shape and “assembly variation” when a permanent magnet is inserted into the shaft portion. When the turbine-compressor part and the shaft part are formed integrally, the balance correction is made for the rotor for the small gas turbine generator having a plurality of unbalance factors such as “shape error” and “assembly variation”. Therefore, it is very difficult to correct the balance.

  On the other hand, in the rotor for a small gas turbine generator of the present embodiment, since the turbine-compressor portion and the shaft portion are detachably coupled, the turbine-compressor portion and the shaft portion are separated from each other in the turbine -The "shape error" can be corrected for the compressor section, and the "assembly variation" when the permanent magnet is inserted into the shaft section can be corrected for the shaft section. In addition, for the shaft portion, the “assembly variation” when inserting the permanent magnet into the shaft portion is corrected, and then the turbine-compressor portion is mounted on the shaft portion, and the “shape error” for the turbine-compressor portion is corrected. May be modified. In any method, after correcting the balance in a state where a plurality of unbalance factors such as “shape error” and “assembly variation” are separated, the balance of the entire rotor for the small gas turbine generator is adjusted in the final assembly state. By performing the correction, it is possible to perform the balance correction with extremely high accuracy compared to the case of performing the balance correction while having a plurality of unbalance factors. That is, after correcting the balance of the turbine-compressor part and the shaft part separately, the turbine-compressor part and the shaft part are combined to form a rotor for a small gas turbine generator with extremely high accuracy as a whole. It becomes possible.

  In the rotor for a small gas turbine generator according to the present embodiment, the turbine-compressor section 4 includes a ceramic turbine section 1 and a rear face (rear face of the compressor section) with respect to the rear face 1a of the turbine section 1 as shown in FIG. The ceramic compressor part 2 joined to the turbine part 1 so that 2a faces and is coaxial, and the coupling shaft part 3 made of ceramic extending from the center of the compressor part 2 and coaxial with the turbine part 1 and the compressor part 2 It is formed integrally. Here, when it is referred to as “integrally formed”, the ceramic forming raw material before firing is formed to form a desired shape (the shape of the turbine-compressor part) and then fired to obtain a desired fired product. To form. The ceramic raw material is a mixture of ceramic powder, water, an organic solvent, a binder, and the like. When the ceramic raw material is molded and fired, the ceramic powders can be bonded to obtain a ceramic sintered body. And when a turbine part, a compressor part, and a connection shaft part are formed integrally, it becomes a turbine-compressor part in which a joint does not exist among each of a turbine part, a compressor part, and a connection shaft part. FIG. 2 is a side view schematically showing a turbine-compressor part constituting one embodiment of a rotor for a small gas turbine generator of the present invention.

  In the turbine-compressor section 4, the rear surface 1 a of the turbine section and the rear surface 2 a of the compressor section may be directly joined, but as shown in FIGS. 1 and 2, they are integrated with each other via the joint section 5. It may be joined to. The joint portion 5 is coaxial with the coupling shaft portion 3. Although the length of the joint part 5 in the central axis direction is not particularly limited, for example, 0.5 to 5 mm is preferable. If it is shorter than 0.5 mm, the heat of the high-temperature combustion gas flowing into the turbine is easily transmitted to the compressor when it is incorporated in the gas turbine, and the efficiency of the compressor may be reduced. If it is longer than 5 mm, the overhang length from the bearing becomes long, so the stability during high-speed rotation may decrease. It is preferable that the junction part 5 is cylindrical. In the turbine section, the side on which the blade section 1b is disposed is the front face, and the opposite face is the back face (the back face 1a of the turbine section). In the compressor section, the side where the blade section 2b is disposed is the front face, and the opposite face is the back face (the back face 2a of the compressor section).

  The material forming the turbine-compressor section 4 is preferably a ceramic material having excellent heat resistance and high strength, and among these, silicon nitride and silicon carbide are preferable. The turbine-compressor unit 4 is integrally formed and is preferably formed of the above-mentioned material as a whole.

  The turbine section 1 constituting the turbine-compressor section 4 is connected to the hub section 1c, the blade section 1b extending radially and connected to the outer periphery of the hub section 1c, and coaxially connected to the hub section 1c on the front side of the hub section 1c. The boss 1d is integrally formed. The diameter (maximum diameter) in the cross section orthogonal to the central axis of the turbine part 1 is preferably 10 to 30 mm, more preferably 15 to 20 mm. If it is smaller than 10 mm, the operating rotational speed of the rotor for the small gas turbine generator of this embodiment needs to be set to 800,000 rpm or more, for example, and the loss at the bearing may become too large. If it is larger than 30 mm, the centrifugal stress during high-speed rotation increases and the wing part may be easily damaged. Moreover, it is preferable that it is 0.1-1 mm, and, as for the thickness of the blade part 1b which comprises the turbine part 1, it is more preferable that it is 0.2-0.5 mm. If it is thinner than 0.1 mm, the strength may be lowered, and if it is thicker than 1 mm, the aerodynamic performance may be lowered.

  The compressor section 2 constituting the turbine-compressor section 4 is formed by integrally forming a hub section 2c and blade sections 2b connected to the outer periphery of the hub section 2c and extending radially. The diameter (maximum diameter) in the cross section orthogonal to the central axis of the compressor unit 2 is preferably 10 to 30 mm, and more preferably 15 to 20 mm. If it is smaller than 10 mm, the compression efficiency may be reduced, and if it is larger than 30 mm, the centrifugal stress during high-speed rotation may increase and the wings may be easily damaged. Moreover, it is preferable that the thickness of the blade | wing part 1b which comprises the compressor part 2 is 0.1-1 mm, and it is still more preferable that it is 0.2-0.5 mm. If it is thinner than 0.1 mm, the strength may be lowered, and if it is thicker than 1 mm, the aerodynamic performance may be lowered.

  The coupling shaft portion 3 constituting the turbine-compressor portion 4 extends coaxially from the center of the front surface of the compressor portion 2 to the compressor portion 2. 2-20 mm is preferable and, as for the length of the coupling shaft part 3, 5-15 mm is still more preferable. If it is smaller than 2 mm, the area of the air intake part of the compressor may be narrowed and the intake resistance may be increased. If it is larger than 20 mm, the overhang length from the bearing becomes long, so stability during high-speed rotation may be reduced. . Moreover, 2-8 mm is preferable and, as for the thickness of the coupling shaft part 3, 3-7 mm is still more preferable. If it is smaller than 2 mm, the mechanical strength may be reduced and breakage may occur easily. If it is larger than 8 mm, the area of the air intake portion of the compressor may be narrowed and the intake resistance may be increased. The coupling shaft portion 3 is preferably cylindrical.

  As shown in FIG. 3, a screw member 21 is preferably attached to the tip of the coupling shaft portion 3 of the turbine-compressor portion 4. Then, it is preferable that the screw portion 21 is screwed to the shaft portion. By attaching the screw member 21 to the tip of the coupling shaft portion 3, the turbine-compressor portion 4 and the shaft portion can be screwed together. In this case, it is preferable to cut a screw corresponding to the screw shape of the screw member 21 on the shaft side. By connecting the turbine-compressor section 4 and the shaft section with screws as described above, the turbine-compressor section 4 and the shaft section can be easily attached and detached. The screw member 21 includes a cylindrical screw portion 22 and a cap-shaped cap portion 23 disposed at one end of the screw portion 22, and the turbine-compressor portion 4 in the center on the cap portion 23 side. A hole for inserting the coupling shaft portion 3 is formed. The screw member 21 and the connecting shaft portion 3 of the turbine-compressor portion 4 are preferably connected by a method such as press fitting or shrink fitting. Further, the screw fastening by the screw member 21 is preferably fast with respect to the rotation direction of the rotor for the small gas turbine generator. Further, instead of attaching the screw member 21 to the tip of the coupling shaft portion 3 of the turbine-compressor portion 4, the coupling shaft portion 3 may be directly threaded. FIG. 3 is a side view schematically showing a state in which a screw member is attached to a turbine-compressor part constituting one embodiment of a rotor for a small gas turbine generator of the present invention.

  As shown in FIG. 1, in the rotor for a small gas turbine generator according to the present embodiment, the shaft portion 15 has a magnet built-in portion 13 in which a permanent magnet 12 can be built and at least two bearing portions 14. is there. The shaft portion 1 is detachably coupled to the end portion 11 thereof so that the shaft portion 1 is coaxial with the coupling shaft portion of the turbine-compressor portion. A screw corresponding to the screw shape of the screw member 21 is cut at the end portion 11 of the shaft portion 15. Further, a thrust collar 18 is disposed at the end 16 of the shaft 15 opposite to the end 11 where the screw is cut, and the shaft 15 is loose when assembled to the gas turbine. Can be suppressed (unnecessary movement in the axial direction can be suppressed). Although the shape of the thrust collar 18 is not particularly limited, for example, as shown in FIG. 1, it is preferably a disk shape having a diameter larger than the diameter of the bearing portion 14. The thrust collar 18 may be a structure that can be detached from the end portion 16 of the shaft portion 15 when the bearing is set on the end portion 16 side, and can be attached so as not to loosen after being assembled to the gas turbine. For example, a method in which the end portion 16 of the shaft portion 15 or the cylindrical member 19 is threaded and tightened with a nut can be exemplified.

  The length of the shaft portion 15 is preferably 20 to 100 mm, and more preferably 30 to 70 mm. If it is shorter than 20 mm, the interval between the bearings becomes narrow, so that it may be difficult to perform stable rotation. If it is longer than 100 mm, the natural frequency of the shaft may be lowered, and stable rotation may be difficult. Moreover, it is preferable that the shape of the axial part 15 is columnar shape (cylindrical shape).

  Examples of the material for forming the shaft portion 15 include metals and ceramics. Among these, a metal is preferable in terms of excellent workability. Of the metals, titanium alloys are preferred because of their high specific strength. Moreover, when the material which forms the axial part 15 is made into a ceramic, the material quoted as a preferable material of the said turbine-compressor part can be used suitably.

  The shaft portion 15 has one bearing portion 14 between the magnet built-in portion 13 and the end portion 11 to which the turbine-compressor portion 4 is coupled, and the magnet built-in portion 13 is opposite to the end portion 11. One bearing portion 14 is further provided between the end portion 16 on the side. The shaft portion 15 has a magnet built-in portion 13 having a hollow portion 17 for embedding a permanent magnet therein between the two bearing portions 14 and 14. Further, a permanent magnet 12 is embedded in the magnet built-in portion 13 (inside the cavity of the magnet built-in portion 13).

  A rotor for a small gas turbine generator has a built-in permanent magnet in a shaft portion, at least two bearing portions are formed so as to sandwich the permanent magnet, and the bearing portions are supported by the bearing. This is preferable from the viewpoint of rotating balance of the rotor for the generator and making the generator compact. In order to incorporate a permanent magnet, the inside of the shaft part is hollow (hollow) and the permanent magnet is incorporated into the hollow part. Generally, however, the magnet material has low mechanical strength and the magnetic force decreases when stress is applied. Therefore, in order to avoid stress on the permanent magnet, it is necessary to ensure sufficient mechanical strength by the magnet built-in portion in which the permanent magnet is embedded. Therefore, the magnet built-in portion 13 and the bearing portion 14 may have the same thickness as in the embodiment of the rotor for a small gas turbine generator of the present invention shown in FIG. As in other embodiments of the rotor for a small gas turbine generator, the magnet built-in portion 13 in which the permanent magnet 12 is embedded is made thicker than the thickness of the bearing portion 14 by increasing the thickness of the wall 13a. More preferably, it is formed. Another embodiment of the rotor for a small gas turbine generator of the present invention is one of the rotors for a small gas turbine generator of the present invention except that the wall 13a of the magnet built-in portion 13 in which the permanent magnet 12 is embedded is thickened. This is the same as the embodiment. FIG. 4 is a side view schematically showing another embodiment of the rotor for a small gas turbine generator of the present invention.

  Further, if the magnet built-in portion 13 is formed thicker than the bearing portion 14, the outer diameter of the turbine-compressor section (diameter in the cross section perpendicular to the central axis) is usually larger than the outer diameter of the shaft section 15. It becomes difficult to insert a bearing portion (intermediate bearing portion) located between the magnet built-in portion and the “end portion where the coupling shaft portion of the turbine-compressor portion is coupled” into the bearing. For example, in the case where the turbine-compressor part and the shaft part are integrally formed, when the intermediate bearing part is inserted into the bearing, it is necessary to pass the turbine-compressor part side or the magnet built-in part side through the bearing. Regardless, both have the problem that the outer diameter is too large to pass through the bearing. On the other hand, in the case of the rotor for a small gas turbine generator of the present invention, the turbine-compressor portion and the shaft portion are detachably coupled, so that the turbine-compressor portion and the shaft portion are separated, By inserting the intermediate bearing portion into the bearing and coupling the turbine-compressor portion and the shaft portion after inserting the intermediate bearing portion into the bearing, the intermediate bearing portion can be easily inserted into the bearing.

  Therefore, in the rotor for a small gas turbine generator of the present invention, the shaft portion is one of the bearing portions between the magnet built-in portion and the “end portion where the combined shaft portion of the turbine-compressor portion is coupled”. And one of the bearing parts (a bearing part formed between the magnet built-in part and the end part to which the coupling shaft part of the turbine-compressor part is coupled) goes straight in the direction of the central axis. Even when the diameter of the cross section is smaller than the diameter of the cross section perpendicular to the central axis direction of the magnet built-in portion, the bearing portion (intermediate bearing portion) can be passed through the bearing, and a higher effect can be achieved.

  In one embodiment of the rotor for a small gas turbine generator of the present invention, the diameter in the cross section perpendicular to the central axis of the cavity portion 17 in which the permanent magnet 12 of the magnet built-in portion 13 is embedded is preferably 4 to 20 mm, 15 mm is more preferable. If it is smaller than 4 mm, the size of the magnet that can be incorporated becomes small, and it may be difficult to secure a sufficient amount of power generation. If it is larger than 20 mm, the magnetic force may decrease due to centrifugal stress during high-speed rotation. The length of the hollow portion 17 in the central axis direction is preferably 4 to 40 mm, and more preferably 10 to 30 mm. If the length is shorter than 4 mm, a desired permanent magnet may not be embedded. If the length is longer than 40 mm, the mechanical strength of the shaft portion 15 may be reduced, and high-speed rotation may be difficult. When a permanent magnet is embedded in the hollow portion 17 of the magnet built-in portion 13, a space portion may remain or the space portion may disappear.

  2-20 mm is preferable and, as for the diameter in the cross section orthogonal to the central axis of the bearing part 14, 3-10 mm is more preferable. If it is thinner than 2 mm, the strength may decrease, and if it is larger than 20 mm, the rotor for a small gas turbine generator may be difficult to rotate at a high speed of 500,000 rpm or more. Further, when the magnet built-in portion 13 is thicker than the bearing portion 14 as in the small gas turbine generator rotor 200 shown in FIG. 4, the diameter of the magnet built-in portion 13 and the bearing portion 14 in the cross section perpendicular to the central axis thereof. The difference from the diameter is preferably 10 mm or less, and more preferably 5 mm or less mm. If it is larger than 10 mm, the outer diameter of the magnet built-in portion 13 is increased, and the rotor for the small gas turbine generator may be difficult to rotate at a high speed of 500,000 rpm or more.

  Moreover, it is preferable that the thickness of the wall surrounding the cavity part 17 of the magnet built-in part 13 is 0.3-3 mm, and it is still more preferable that it is 0.5-2 mm. If it is thinner than 0.3 mm, it may be difficult to ensure the mechanical strength by the magnet built-in part 13. If it is larger than 3 mm, the outer diameter of the magnet built-in part 13 will be large, and the rotor for the small gas turbine generator will be 500,000 rpm. It may become difficult to rotate at the above high rotation.

  In the rotor for a small gas turbine generator according to the present invention, a through hole is formed in the central shaft portion of the turbine-compressor portion, and one end portion of the shaft portion is disposed on the compressor portion side of the through hole of the turbine-compressor portion. Inserted from the opening, made into an elongated shape that penetrates from the opening on the turbine side, and is threaded into the part that has penetrated the turbine-compressor at one end of the shaft and fixed with a nut It may be. In addition, the rotor for a small gas turbine generator according to the present invention forms a through hole in the central shaft portion of the turbine-compressor portion and also forms a through hole in the central shaft portion of the shaft portion. In a state where the parts are connected, a tension bolt may be passed through the two through holes, and both ends may be fastened with nuts and fixed.

2. Manufacturing method of rotor for small gas turbine generator:
Ceramic powder, binder, solvent and the like are mixed, and then kneaded by a kneader to produce a ceramic forming raw material. As the ceramic powder, silicon nitride, silicon carbide or the like is preferably used. The ratio of the ceramic powder to the whole forming raw material is preferably 50 to 80% by mass. As the binder, isocyanate, cellulose, butyral, or the like is preferably used. The ratio of the binder to the whole forming raw material is preferably 1 to 5% by mass.

The green molding is obtained by carrying out cold isostatic pressing (CIP) of the obtained shaping | molding raw material. The shape of the green molded body is not particularly limited, but a cylindrical shape, a rectangular parallelepiped or the like is preferable. The size of the green molded body is preferably about 2 to 500 cm ³ .

  The obtained green molded body is calcined to prepare a calcined body. Organic components such as binder are removed by calcining. The calcining conditions are a nitrogen atmosphere and heating at 1000 to 1500 ° C. for 1 to 5 hours.

  Next, the calcined body is processed to form the shape of the turbine-compressor part, and the calcined turbine-compressor part is manufactured. The processing method is preferably cutting. As the processing apparatus, it is preferable to use an NC processing machine. It is preferable to impregnate the calcined body with silicone oil before cutting. By impregnating with silicone oil, cutting can be easily performed.

  Next, the calcining turbine-compressor part is fired (main firing) to produce a turbine-compressor part 4 as shown in FIG. The firing conditions are a nitrogen atmosphere and heating at 1700-1800 ° C. for 3-6 hours.

  A screw member 21 as shown in FIG. 3 is produced on a lathe. The screw member 21 includes a cylindrical screw portion 22 and a cap-shaped cap portion 23 disposed at one end of the screw portion 22. And the hole which inserts the coupling shaft part 3 of the turbine-compressor part 4 is formed in the center at the side of the shade part 23 of the screw member 21. The screw portion 22 may be a female screw or a male screw.

  Next, the coupling shaft portion 3 of the turbine-compressor portion 4 is press-fitted into the hole formed in the screw member 21. It is preferable to form the screw portion so as to be tightened with respect to the rotation direction of the turbine-compressor portion.

  Next, the shaft portion is manufactured. The shaft portion is preferably manufactured while adjusting the balance when coupled to the turbine-compressor portion 4.

  It is preferable to use a cylindrical metal or ceramic as a material for producing the shaft portion. In view of easy processing, it is more preferable to use a columnar metal. Moreover, as a metal, a titanium alloy is preferable. The length and thickness of the columnar metal or ceramic are preferably the length and thickness of the shaft portion to be produced.

  First, one end of a columnar metal or ceramic (shaft material) is threaded in a shape corresponding to the threaded portion 22 of the threaded member 21 attached to the turbine-compressor portion to obtain a threaded cylindrical body. Form. When the screw portion 22 is a male screw, a female screw having a corresponding shape (a shape that can be screw-fastened) is formed. Moreover, when making a magnet built-in part thicker than a bearing part, it is preferable to carry out the lathe process so that the part corresponded to a bearing part may become desired thickness.

  Next, the threaded portion of the threaded cylinder and the screw member of the turbine-compressor part are screwed together, and the external shape of the threaded cylinder and the turbine-compressor part, which are joined by screw fastening, is precisely It is preferable to perform trimming by lathe processing so that the coaxiality between the threaded cylindrical body and the turbine-compressor unit is equal to that of the integrally molded product.

  A hollow portion for incorporating a permanent magnet is formed from the “end opposite to the threaded end” of the threaded cylindrical body to form a shaft portion. The cavity is preferably formed by precision lathe processing.

  Next, as shown in FIG. 5A, the cylindrical permanent magnet 12 is inserted into the cavity 17 of the threaded cylindrical body from the "end 16 opposite to the threaded end" and fixed by adhesion. Or press fit. When using an adhesive, it is preferable to use an epoxy adhesive or the like.

  After the magnet is inserted and fixed, as shown in FIG. 5B, from the “end 16 on the opposite side of the threaded end” of the threaded cylindrical body, it is solid with the same material as the threaded cylindrical body. It is preferable to insert the cylindrical member 20 to fill the cavity 17. When the cylindrical member 20 is inserted, it is preferable that the cylindrical member 20 is integrated with the threaded cylindrical body by a method such as press fitting, adhesion, or welding. Thereby, the intensity | strength of a cavity part can be improved.

  Next, as shown in FIG. 5C, it is preferable to form the projection 24 while trimming the end of the threaded cylindrical body on which the cylindrical member 20 is embedded by trimming by precision lathe processing to ensure the same axis. Then, by inserting the ring-shaped thrust collar 18 (see FIG. 1) and the ring-shaped cylindrical member 19 (see FIG. 1) into the protrusion 24, the rotor 100 for the small gas turbine generator (see FIG. 1). It is preferable that When the thrust collar 18 and the cylindrical member 19 are fitted, it is preferable that the protrusion 24 (end portion 16), the thrust collar 18 and the cylindrical member 19 are screwed and screwed. The thrust collar 18 may be connected to the protruding portion 24 (end portion 16) or may be connected to the cylindrical member 19. In the case of manufacturing another embodiment of the rotor for a small gas turbine generator of the present invention shown in FIG. 4, when the end of the threaded cylindrical body on the side where the cylindrical member 20 is embedded is precision lathe processed. Further, it is preferable to form the shape of the bearing portion 14. 5A to 5C are schematic views showing a manufacturing process of one embodiment of the rotor for a small gas turbine generator of the present invention.

  Also, instead of turning the cylindrical member after inserting the cylindrical member into the threaded cylindrical body, a cylindrical member having a protrusion is inserted into the threaded cylindrical body so that the subsequent lathe machining is omitted. May be. In addition, when manufacturing another embodiment of the rotor for a small gas turbine generator of the present invention shown in FIG. 4, a cylindrical member formed with a protrusion and a bearing is inserted into a threaded cylindrical body, Later lathe machining may be omitted. When manufacturing another embodiment of the rotor for a small gas turbine generator according to the present invention, the bearing portion 14 is turned on the “end opposite to the threaded end” of the threaded cylindrical body. You may make it abbreviate | omit a later lathe process by inserting the cylindrical member in which it formed by the process and the projection part was formed in it.

  In addition, as a method for producing the shaft portion, a method in which a magnet is inserted into a cylindrical member having both ends opened and a solid member processed into a desired shape is fitted to both end portions is also a preferable method. This is a particularly suitable method for manufacturing another embodiment of the rotor for a small gas turbine generator of the present invention shown in FIG.

  In order to adjust the rotor balance necessary for high-speed rotation, first, the two-surface balance correction is performed only with the shaft portion incorporating the permanent magnet. As a correction method, it is desirable to grind and remove the unbalanced weight based on the result of balance measurement using a soft type autobalancer. Thereafter, the turbine-compressor portion is screwed and the balance is further corrected to obtain a rotor for a small gas turbine generator. By this method, it is possible to separate and correct the unbalance factor between the shaft portion and the turbine-compressor portion, and it is possible to easily produce a rotor for a small gas turbine generator excellent in rotational balance.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1
A rotor for a small gas turbine generator as shown in FIG. 1 was produced.

  First, a cylindrical green molded body of silicon nitride ceramics formed by cold isostatic pressing (CIP) was calcined to prepare a calcined body. Organic components such as a binder were removed by calcining. The calcining conditions were a nitrogen atmosphere and heating at 1300 ° C. for 2 hours. The calcined body had a bottom diameter of 30 mm and a height of 30 mm.

  Next, the calcined body was processed to form the shape of the turbine-compressor part, and the calcined turbine-compressor part was produced. The processing method was cutting using an NC processing machine. Prior to cutting, the calcined body was impregnated with silicone oil to facilitate cutting.

  Next, the calcined turbine-compressor part was fired (main firing) to produce a turbine-compressor part 4 as shown in FIG. The firing conditions were a nitrogen atmosphere and heating at 1800 ° C. for 5 hours. The outer diameter of the turbine section and the compressor section constituting the turbine-compressor section was 15 mm, and the minimum thickness of the blade sections of the turbine section and the compressor section was 0.3 mm.

  A screw member 21 as shown in FIG. 3 was produced by precision lathe processing. The screw member 21 includes a cylindrical screw portion 22 and a cap-shaped cap portion 23 disposed at one end of the screw portion 22. A hole for inserting the coupling shaft portion 3 of the turbine-compressor portion 4 was formed in the center of the screw member 21 on the side of the shade portion 23. The screw portion 22 was a male screw. The length of the screw portion 22 was 5 mm, and the diameter of the cross section perpendicular to the central axis direction (diameter including the screw thread) was 6 mm.

  Next, the coupling shaft portion 3 of the turbine-compressor portion 4 was press-fitted into the hole formed in the screw member 21. The screw part was formed so as to be tightened with respect to the rotation direction of the turbine-compressor part.

  Next, a shaft portion was produced. The shaft portion was produced while adjusting the balance when combined with the turbine-compressor portion.

  A cylindrical titanium alloy having a bottom diameter of 8 mm and a length of 40 mm was used as a material for producing the shaft portion.

  First, at one end of a cylindrical metal or ceramic (shaft material), a female screw having a shape corresponding to the screw portion 22 of the screw member 21 attached to the turbine-compressor portion is formed to form a threaded cylindrical body. Formed. The female thread was formed by precision lathe machining.

  Next, the threaded cylindrical body and the screw member of the turbine-compressor part are screw-fastened, and the external shape of the screw-worked cylindrical body and the turbine-compressor part in a state of being coupled by screw fastening Was trimmed by precision lathe machining. Thereby, the coaxiality of the threaded cylindrical body and the turbine-compressor portion was processed so as to be equivalent to that of the integrally molded product.

  Next, a hollow portion for containing a permanent magnet was formed from the end of the threaded cylindrical body opposite to the end subjected to the threading to form a shaft portion. The diameter of the cross section perpendicular to the axial direction of the hollow portion was 6 mm, and the length in the central axis direction was 35 mm. The cavity was formed by precision lathe processing.

  Next, a cylindrical permanent magnet is inserted into the hollow portion of the threaded cylindrical body and bonded and fixed. The permanent magnet was a cylinder having a length of 23 mm and a bottom diameter of 6 mm. The diameter of the bottom surface of the permanent magnet was slightly smaller than the diameter of the cross section of the cavity, and the permanent magnet was sized to fit in the cavity. An epoxy adhesive was used as the adhesive.

  In order to adjust the rotor balance required for high-speed rotation, the two-surface balance was corrected only with the shaft portion with a built-in permanent magnet. The two-surface balance correction was performed by grinding and removing unbalanced mass based on the result of balance measurement using a soft type autobalancer. Thereafter, the turbine-compressor portion was screwed and the balance was further corrected to obtain a rotor for a small gas turbine generator.

  The produced rotor for a small gas turbine generator was incorporated into a rotation tester equipped with a predetermined bearing, and the turbine portion was rotated at a rotational speed of about 600,000 rpm with heated air. It was confirmed that stable rotation was possible at a rotation speed of 600,000 rpm.

  The rotor for a small gas turbine generator of the present invention can be suitably used as a rotor for an ultra-compact gas turbine generator that generates an electric output of 1 kW or less that is used as a power source that is small, lightweight, and capable of operating for a long time. it can.

It is a side view showing typically one embodiment of a rotor for small gas turbine generators of the present invention. It is a side view which shows typically the turbine-compressor part which comprises one Embodiment of the rotor for small gas turbine generators of this invention. It is a side view which shows typically the state which attached the screw member to the turbine-compressor part which comprises one Embodiment of the rotor for small gas turbine generators of this invention. It is a side view which shows typically other embodiment of the rotor for small gas turbine generators of this invention. It is a schematic diagram which shows the manufacture process of one Embodiment of the rotor for small gas turbine generators of this invention. It is a schematic diagram which shows the manufacture process of one Embodiment of the rotor for small gas turbine generators of this invention. It is a schematic diagram which shows the manufacture process of one Embodiment of the rotor for small gas turbine generators of this invention.

Explanation of symbols

1: turbine part, 1a: rear face of turbine part, 1b, 2b: blade part, 1c, 2c: hub part, 1d: boss part, 2: compressor part, 2a: rear face of compressor part, 3: coupling shaft part, 4 : Turbine-compressor part, 5: joint part, 11: end part, 12: permanent magnet, 13: magnet built-in part, 13a: wall, 14: bearing part, 15: shaft part, 16: end part, 17: cavity part 18: Thrust collar, 19: Cylindrical member, 20: Column member, 21: Screw member, 22: Screw portion, 23: Cap portion, 24: Projection portion, 100, 200: Rotor for small gas turbine generator.

Claims (3)

A ceramic turbine section, a ceramic compressor section joined to the turbine section so that the rear surface faces and is coaxial with the rear surface of the turbine section, and the turbine section and the compressor extending from the center of the compressor section A turbine-compressor part in which a ceramic coupling shaft part coaxial with the part is integrally formed;
A magnet built-in portion capable of incorporating a permanent magnet and having at least two bearing portions, the end of which is detachably coupled to the coupling shaft portion so as to be coaxial with the coupling shaft portion of the turbine-compressor portion. And a rotor for a small gas turbine generator.   The shaft portion has one of the bearing portions between the magnet built-in portion and an end portion to which the combined shaft portion of the turbine-compressor portion is coupled, and is one of the bearing portions. The rotor for a small gas turbine generator according to claim 1, wherein a diameter of a cross section perpendicular to the central axis direction is equal to or smaller than a diameter of a cross section perpendicular to the central axis direction of the magnet built-in portion.   The rotor for a small gas turbine generator according to claim 1 or 2, wherein a coupling method between the turbine-compressor part and the shaft part is screw fastening, and the screw fastening is self-tightening in a rotation direction.

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