CA2972225A1

CA2972225A1 - Rotor

Info

Publication number: CA2972225A1
Application number: CA2972225A
Authority: CA
Inventors: Jin Woo Choi; Kuk Tae Kim; Ji Hyo OK; Jae Young Park; Bae Han LEE; Chang In BYEON
Original assignee: Hyosung Corp
Current assignee: Hyosung Heavy Industries Corp
Priority date: 2014-12-24
Filing date: 2015-12-23
Publication date: 2016-06-30
Also published as: KR101711457B1; JP2018501773A; WO2016105113A1; KR20160078184A

Abstract

The present invention relates to a rotor. The rotor of the present invention comprises: a rotary shaft (10) having supporting parts (12) at both ends of a hollow part (14); and a plurality of salient poles (24) provided at predetermined intervals on the outer surface of the hollow part (14), and has a plurality of cooling fans (26) arranged along both end edges of the hollow part (14) so as to form an air current flowing to the salient poles (24). The hollow part (14) has an inner space (20) formed therein, and ejection holes (22) are formed to be open to the outer surface of the hollow part (14) so as to make the inner space (20) communicate with the outside. The ejection holes (22) are formed in a region extending from the longitudinal middle of the hollow part (14) toward both end portions thereof. Flanges (16) are formed at the end portions of the supporting parts (12), and inflow holes (18) are formed at the flanges (16) so as to allow air to flow into the inner space (20) due to a difference in air pressure generated by rotation. According to the present invention as above, the weight of the rotor can be reduced and heat generated from the rotor can be smoothly emitted to the outside, thereby improving the performance and lifespan of the rotor.

Description

Attorney Ref.: 1145P006CA01 ROTOR
TECHNICAL FIELD
The present invention relates to a rotor, and more particularly, to a rotor relatively rotating with respect to a stator in a generator or a motor.
BACKGROUND
A generator, a motor, and the like perform a desired function by rotating a rotor by an electromagnetic interaction between the rotor and a stator. The rotor is required to be lighter, since the rotor relatively rotates with respect to the stator.
Since the rotor rotates with respect to the stator for a long time though the electromagnetic interaction, it is necessary to smoothly dissipating heat generated in the rotor and the stator to the outside.
However, a hydraulic turbine generator having a rotary shaft that is several meters long and on which a rotor is disposed has a problem in that heat is not properly dissipated from a middle portion in the lengthwise direction of such a rotary shaft.
In addition, since heat is not properly dissipated from a coil portion of the rotor corresponding to the middle portion in the lengthwise direction of the rotary shaft that is several meters long, the hydraulic turbine generator has a problem in that operation performance of a rotor or a stator is reduced, or the rotor or the stator is damaged by heat. This is because the middle portion in the lengthwise direction of the rotary shaft that is several meters long is a portion to which it is most difficult for outside air be supplied.
Since rotors of existing rotors used in a large hydraulic turbine generator are heavy, it is necessary to remove elements interrupting rotation through lightening and to facilitate a movement of the rotors after the manufacture of the rotors.

Attorney Ref.: 1145P006CA01 SUM MARY
Technical Problem Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to reduce the weight of a rotor used in a large generator or a large motor.
Another object of the present invention is to allow heat to be smoothly dissipated from a central portion in the lengthwise direction of a rotor used in a large generator or a large motor.
Technical Solution ln order to achieve the above object, according to one aspect of the present invention, there is provided a rotor including: a rotary shaft having support portions and a hollow part in which an inner space and inflow holes are formed, the support portions being disposed at both ends of the hollow part, and the inflow holes allowing outside air to flow into the inner space therethrough; and salient poles disposed at predetermined intervals on an outer surface of the hollow part. Ejection holes are opened through portions of the outer surface of the hollow part, placed between the salient poles such that while air that has entered the inner space of the hollow part is being discharged to an outside through the ejection holes, the air dissipates heat from the hollow part and the salient poles.
A plurality of the ejection holes may be formed in the outer surface of the hollow part and arranged from a region corresponding to a middle portion in a lengthwise direction of the hollow part to both ends of the hollow part.
The inner space formed in the hollow part may be opened though the both ends of the hollow part, flanges disposed at end portions of the support portions may be attached together to the hollow part, and inflow holes may be formed in the flanges to allow cooling air to enter the inner space.
A plurality of the inflow holes may be formed to form a circular trajectory along the flanges.
Through-holes may be formed in the flanges, the though-holes being penetrated by coupling members connecting the flanges disposed at the end portions of the support portions disposed at the both ends of the hollow part.

2 Attorney Ref.: 1145P006CA01 The through-holes may be disposed in positions of the flanges, corresponding to positions on which the salient poles are disposed.
According to one aspect of the present invention, there is provided a rotor including: a rotary shaft; a hollow part allowing the rotary shaft to penetrate a central portion thereof, the hollow part having an inner space therein opened through both sides thereof; shaft spiders supporting the hollow part with respect to the rotary shaft; and salient poles disposed at predetermined intervals on an outer surface of the hollow part. While air in the inner space is being discharged to the outside through portions of the outer surface of the hollow part, placed between the salient poles, the air dissipates heat from the hollow part and the salient poles.
The hollow part may have a plurality of ejection holes in the outer surface thereof, through which the air in the inner space is discharged, the plurality of ejection holes being arranged from a region corresponding to a middle portion in a lengthwise direction of the hollow part to both ends of the hollow part.
The hollow part may be formed by stacking a plurality of boards, and the air in the inner I 5 space is discharged through the outer surface by forming gaps between the plurality of boards.
The ejection holes and the gaps may be disposed in the outer surface of the hollow part, between regions on which the salient poles are mounted.
Advantageous Effects As described above, a rotor according to the present invention has advantages as follows.
First, in the present invention, since a hollow part is disposed in a middle portion in the lengthwise direction of a rotary shaft and heat is dissipated from a rim core and salient poles while air flows into the hollow part and is discharged in the centrifugal direction of the rotor, heat is more smoothly dissipated from the rotor. It is possible to prevent local deterioration and improve a lifespan and performance of a device by smoothly supplying cooling air to a rotor center to which the cooling air has difficulty in accessing.

3 Attorney Ref.: 1145P006CA01 In the present invention, since the hollow part is disposed in the middle portion in the lengthwise direction of the rotary shaft, the weight of the rotor is reduced as a whole. In particular, since the rotary shaft has support portions at both ends thereof and a hollow part at a middle portion thereof, weight may be reduced due to the hollow part. Accordingly, energy consumed to rotate the rotor may be minimized, thereby minimizing an effort necessary for handing such as a transfer or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic cross-sectional view illustrating a configuration of a rotor according to a preferred embodiment of the present invention.
FIG. 2 is a front view illustrating a configuration of a rotary shaft viewed from one end of the rotor, according to an embodiment of the present invention.
FIG. 3 is an exploded perspective view illustrating a main configuration according to an embodiment of the present invention.
FIG. 4 is an operation state view illustrating a state in which air flows in the rotor, according to an embodiment of the present invention.
FIG. 5 is a longitudinal cross-sectional view illustrating a configuration according to another embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating the configuration according to the embodiment shown in FIG. 5.
FIG. 7 is an operation state view illustrating a state in which air flows in the embodiment shown in FIG. 5.
Mode for Invention Hereinafter, some embodiments of the present invention will be described in detail with reference to the exemplary drawings. It is to be noted that in giving reference numerals to elements of each drawing, like reference numerals refer to like elements even though like elements

4 Attorney Ref.: 1145P006CA01 are shown in different drawings. Further, in describing embodiments of the present invention, well-known functions or constructions will not be described in detail since they may unnecessarily obscure the understanding of the present invention.
It will also be understood that, while terms such as "first," "second," "A,"
"B," "(a)," and "(b)" may be used herein to describe various elements, such terms are merely used to distinguish one element from another element. The substance, sequence, order, or number of these elements is not limited by these terms. It will be understood that when an element is referred to as being "connected," or "coupled," to another element, it can be directly connected or coupled to the other element or intervening elements may be present.
As shown in drawings, a rotor according to an embodiment of the present invention is used in a rotary device such as a generator or a motor, in particular, a large generator or a large motor.
A rotational center of the rotor becomes a rotary shaft 10. The rotary shaft 10 has a length of several meters in the present invention. The rotary shaft 10 has support portions 12 at both ends thereof and a hollow part 14 at a middle portion thereof. The support portions 12 are rotatably supported by bearings (not shown) disposed in a housing of a rotary device.
The support portions 12 have a cylindrical shape in the present embodiment. Of course, the support portions 12 have a tubular shape. The support portions 12 may have any shape as long as at least the outer surfaces of portions thereof supported by the bearings are circular.
Flanges 16 are formed at both ends of the support portions 12. The Flanges 16 are formed in a disc shape. A plurality of inflow holes 18 are formed so as to penetrate the flange 16. The inflow holes 18 are configured to allow outside air to flow into an inner space 20 described below.
The plurality of inflow holes 18 are formed in the flange 16, and a trajectory thereof forms a circular shape. The inflow holes 18 and the formation trajectories thereof may have various shapes according to a design condition.
On the other hand, the flanges 16 are coupled through a bolt (not shown) for connecting the support portions 12 at the both ends to each other. To this end, through-holes (not shown) may be formed in the flanges 16 and may be placed on a trajectory equal to or different from the trajectory

5 Attorney Ref.: 1145P006CA01 of the inflow holes 18. The through-holes are not illustrated in drawings for convenience of description. A connection structure between the support portions 12 and the hollow part 14 may be variously designed. However, the connection hole should be designed such that the bolt penetrating the through-hole does not hinder air from flowing through ejection holes 22.
The inner space 20 is formed in the hollow part 14. The inner space 20 is opened though both ends of the hollow part 14, and opened portions of the inner space 20 are shielded from the outside by the flanges 16. Stepped portions 21 are formed on inner surfaces of both inlets of the inner space 20, respectively. The stepped portions 21 are portions on which the flanges 16 are stably disposed. An inner diameter of the inner space 20 inside of the stepped portions 21 is smaller than an inner diameter of the inner space 20 outside of the stepped portions 21. The flanges 16 do not enter the inner space 20 with respect to the stepped portions 21.
The hollow part 14 acts as a rim core, and salient poles 24 described below are mounted on the outer surface of the hollow part 14. A plurality of ejection holes 22 penetrate the hollow part 14 to be opened through the outer surface of the hollow part 14. The inner space 20 communicates with the outside through the ejection holes 22. The ejection holes 22 are intensively formed in a central region in the lengthwise direction of the hollow part 14, so as to efficiently dissipate heat from middle portions of the salient poles 24. In particular, the ejection holes 22 are formed to be opened through the outer surface of the hollow part 14, on which the salient poles 24 described below are not mounted. The plurality of ejection holes 22 are formed in the outer surface of the hollow part 14 from a region corresponding to a middle portion in the lengthwise direction of the hollow part 14 to both ends of the hollow part 14.
While air entering the inner space 20 through the inflow holes 18 is discharged though the ejection holes 22, the air dissipates heat from the hollow part 14 itself and the salient poles 24 to the outside. As shown in FIG. 3, the ejection holes 22 are formed to be opened though a region of the outer surface of the hollow part 14, on which the salient poles 24 are not formed. The plurality of ejection holes 22 form a line or are formed in a predetermined region.

6 Attorney Ref.: 1145P006CA01 The salient poles 24 are mounted on the hollow part 14, i.e., the outer surface of the rim core. The salient poles 24 are formed by winding a coil on a stacked core. A
plurality of salient poles 24 are mounted at predetermined intervals on the hollow part 14. The salient poles 24 may be mounted on the outer surface of the hollow part 14 by using a dovetail structure or a bolt.
A plurality of cooling fans 26 are disposed along edges of both ends of the hollow part 14.
The cooling fans 26 naturally guide air according to the rotation of the rotor to allow cooling air to flow toward the salient poles 24 and the outer surface of the hollow part 14.
The locations and the number of the cooling fans 26 are changed according to a design condition of the rotor.
As shown in FIGS. 5 to 7, a rotary shaft 110 is provided at the rotational center of the rotor according to the present embodiment. The rotary shaft 110 has support portions 112 on both ends, supported by bearings (not shown). The support portions 112 are rotatably supported by the bearings (not shown) disposed in the housing of a rotary device.
A plurality of shaft spiders 113 are disposed along an outer surface of the rotary shaft 110.
A hollow part 114 is disposed across a predetermined region from a middle portion in the lengthwise direction of the rotary shaft 110 to both ends of the rotary shaft 110 by the shaft spiders 113. The hollow part 114 is formed in a tubular shape and acts as a rim core.
An inner space 116 is formed in the hollow part l 14. The rotary shaft 110 penetrates a center of the inner space 116, and the shaft spiders 113 connect an inner surface of the inner space 116 and the rotary shaft 110.
The inner space 116 has both opened ends to communicate with the outside.
A plurality of ejection holes 118 are formed so as to penetrate the hollow part 114 and are opened through an outer surface of the hollow part 114. The inner space 116 communicates with the outside through the ejection holes 118. The ejection holes 118 are intensively formed in a central region in the lengthwise direction of the hollow part 114, so as to effectively dissipate heat from a middle portion of salient poles 120 described below. In particular, the ejection holes 118 are formed to be opened through the outer surface of the hollow part 114, on which the salient poles 120 described below are not mounted. The plurality of ejection holes 118 are formed in the outer surface of the hollow part 114 from a region corresponding to a middle portion in the lengthwise

7 Attorney Ref.: 1145P006CA01 direction of the hollow part 114 to both ends of the hollow part 114. For reference, the hollow part 114 may be formed by stacking a plurality of boards. In this case, gaps may be formed between the boards to substitute for the ejection holes 118.
While air entering the inner space 116 through the both ends of the inner space 116 is discharged though the ejection holes 118, the air dissipates heat from the hollow part 114 itself and the salient poles 120 to the outside. As shown in FIG. 6, the ejection holes 118 are formed to be opened though a region of an outer surface of the hollow part 114, on which the salient poles 120 are not formed. The plurality of ejection holes 118 form a line or are formed in a predetermined region.
The salient poles 120 are mounted on the hollow part 114, i.e., an outer surface of the rim core. The salient poles 120 are formed by winding a coil on a stacked core. A
plurality of salient poles 120 are mounted at predetermined intervals on the hollow part 114. The salient poles 120 may be mounted on the outer surface of the hollow part 114 by using a dovetail structure or a bolt.
A plurality of cooling fans 122 are disposed along edges of both ends of the hollow part 114. The cooling fans 122 naturally guide air according to the rotation of the rotor to allow cooling air to flow toward the salient poles 120 and the outer surface of the hollow part 114. The locations and the number of the cooling fans 122 may vary according to the design condition of the rotor.
Hereinafter, uses of the rotor having the aforementioned configuration according to the present invention will be described in detail.
First, in the embodiment shown in FIG. 1, the rotor 10 is formed by coupling the flanges l 6 of the support portions 12 and the stepped portions 21 in both inlets of the inner space 20 in a state in which the flanges 16 closely contact the stepped portions 21. Since weight corresponding to a volume of the inner space 20 is removed due to the formation of the inner space 20 in the hollow part 14, the aforementioned rotary shaft 10 is relatively lighter than a rotor having the same size.
When the plurality of salient poles 24 are mounted at predetermined intervals on the outer surface of the hollow part 14 as shown FIG. 2, the assembly of the rotor is completed. The rotor as

8 Attorney Ref.: 1145P006CA01 formed above is disposed in a space formed in a stator in a rotary device such as a generator or a motor. At this time, the support portions 12 at the both ends are supported by the bearings disposed in the housing of the rotary device.
The rotor disposed in the rotary device rotates by an electromagnetic interaction with a stator. That is, the rotor rotates by an electromagnetic interaction between a coil of the salient poles 24 and a coil of the stator. When the aforementioned rotation is generated by the electromagnetic interaction, heat is generated in the coils. When the heat is not smoothly dissipated to the outside, rotation performance of the rotor is reduced, or the rotor is damaged.
The dissipation of heat generated in the rotor and the stator will be described with reference to FIG. 4. When the rotary shaft 10 rotates, the cooling fans 26 operate integrally with the rotary shaft 10, and the operation of the cooling fans 26 forms a current of air. The current of air is directly transmitted to the salient poles 24 and the outer surface of the hollow part 14. The plurality of cooling fans 26 are disposed along edges of both ends of the hollow part 14 and allow air to flow from both ends in the lengthwise direction of the hollow part 14 to a middle portion of the hollow part 14. The current of air as formed above absorbs heat while contacting the salient poles 24 and the outer surface of the hollow part 14.
However, when the rotary shaft 10 rotates, air around the salient poles 24 forms a current of air in the centrifugal direction. Accordingly, most of current of air formed by the cooling fans 26 is not transferred to a center portion of the salient poles 24 and is transferred to the stator. Since the pressure of air inside the center portion of the salient poles 24 and the hollow part 14 is lowered, air is discharged from the inner space 20 to the outside of the hollow part 14 through the ejection holes 22 opened though the outer surface of the hollow part 14.
Since air flows into the inner space 20 through the inflow holes 18 formed in the flanges 16 of the support portions 12 at the both ends, air flows in the inner space 20 encounter each other near the ejection holes 22, and the air is discharged to the outside through the ejection holes 22.
The air discharged through the ejection holes 22 acts to dissipate heat from a region corresponding to a middle portion in the lengthwise direction of the rotor.
Therefore, the cooling

9 Attorney Ref.: 1145P006CA01 fans 26 may compensate a fact that a current of air formed from the both ends to the middle portion of the salient poles 24 does not reach the middle portion of the salient poles 24 and flows in the centrifugal direction of the rotor not to dissipate heat from the middle portion, and thus the middle portion is overheated.
In other words, the ejection holes 22 of the hollow part 14 are configured to intensively transfer air to a central region in the lengthwise direction of the hollow part 14 and a central portion of the salient poles 24 to intensively dissipate heat from a corresponding portion. Therefore, heat generated by the rotor may be entirely and smoothly dissipated to the outside.
As described above, currents of air formed in the centrifugal direction from the rotor are constantly maintained with respect to an entire region in the lengthwise direction of the rotor by the ejection holes 22, and thus, a current of air transmitted to the stator is uniform as shown in FIG. 4.
Accordingly, heat generated in the stator may be smoothly dissipated.
On the other hand, since the dissipation of heat in the embodiment shown in FIGS. 5 to 7 is similar to the dissipation of heat in the embodiment described above, the description will be simply provided. That is, when the rotary shaft 110 rotates, an atmospheric pressure is lowered in the inner space 116 of the hollow part 114. Accordingly, air is transferred from the inner space 116 to the outside of the hollow part 114 through the ejection holes 118 as shown in FIG. 7. Of course, currents of air formed by the cooling fans 122 are formed along the outer surface of the hollow part 114 to cool the salient poles 120.
Here, air discharged from the inner space 116 through the ejection holes 118 may intensively dissipate heat to the outside from the salient poles 120 and the middle portion of the hollow part 114.
Although the exemplary embodiments of the present disclosure have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from essential characteristics of the disclosure.
Therefore, exemplary embodiments of the present disclosure have not been described for limiting Attorney Ref.: 1145P006CA01 purposes. Accordingly, the scope of the disclosure is not to be limited by the above embodiments but by the claims and the equivalents thereof.
In the embodiments described for reference, the flanges 16 of the support portions 12 are coupled to the hollow part 14 through the bolt, but the embodiments are not necessarily limited thereto. For example, the flanges 16 of the support portions 12 may be directly coupled to the hollow part 14 without using the bolt, or the support portions 12 may be integrally formed into the hollow part 14. That is, the rotary shaft 10 may be manufactured by using a three-dimensional (3D) printer to integrally form the support portions 12 and the hollow part 14.
As in the embodiments shown, when the support portions 12 and the hollow part 14 are separately formed and are coupled to each other, air may also flow into the inner space 20 though gaps or the like between the flanges 16 and the hollow part. In this case, the gaps become the inflow holes 18.
The inflow holes 18 and the ejection holes 22 are illustrated in the embodiments as being formed in a circular shape, but the embodiments are not limited thereto. The inflow holes 18 and the ejection holes 22 may have not only the circular shape, but also a variety of other shapes, such as an oval shape and a polygonal shape.

Claims

What is claimed is:

1. A rotor comprising:
a rotary shaft having support portions and a hollow part in which an inner space and inflow holes are formed, the support portions being disposed at both ends of the hollow part, and the inflow holes allowing outside air to flow into the inner space therethrough; and salient poles disposed at predetermined intervals on an outer surface of the hollow part, wherein ejection holes are opened through portions of the outer surface of the hollow part, placed between the salient poles such that while air that has entered the inner space of the hollow part is being discharged to an outside through the ejection holes, the air dissipates heat from the hollow part and the salient poles.

2. The rotor of claim 1, wherein a plurality of the ejection holes are formed in the outer surface of the hollow part and arranged from a region corresponding to a middle portion in a lengthwise direction of the hollow part to both ends of the hollow part.

3. The rotor of claim 2, wherein the inner space formed in the hollow part is opened though the both ends of the hollow part, flanges disposed at end portions of the support portions are attached together to the hollow part, and inflow holes are formed in the flanges to allow cooling air to enter the inner space.

4. The rotor of claim 3, wherein a plurality of the inflow holes are formed to form a circular trajectory along the flanges.

5. The rotor of any one of claims 1 to 4, wherein through-holes are formed in the flanges, the though-holes being penetrated by coupling members connecting the flanges disposed at the end portions of the support portions disposed at the both ends of the hollow part.

6. The rotor of claim 5, wherein the through-holes are disposed in positions of the flanges, corresponding to positions on which the salient poles are disposed.

7. A rotor comprising:
a rotary shaft;
a hollow part allowing the rotary shaft to penetrate a central portion thereof, the hollow part having an inner space therein opened through both sides thereof;
shaft spiders supporting the hollow part with respect to the rotary shaft; and salient poles disposed at predetermined intervals on an outer surface of the hollow part, wherein, while air in the inner space is being discharged to the outside through portions of the outer surface of the hollow part, placed between the salient poles, the air dissipates heat from the hollow part and the salient poles.

8. The rotor of claim 7, wherein the hollow part has a plurality of ejection holes in the outer surface thereof, through which the air in the inner space is discharged, the plurality of ejection holes being arranged from a region corresponding to a middle portion in a lengthwise direction of the hollow part to both ends of the hollow part.

9. The rotor of claim 7, wherein the hollow part is formed by stacking a plurality of boards, and the air in the inner space is discharged through the outer surface by forming gaps between the plurality of boards.

10. The rotor of any one of claims 7 to 9, wherein the ejection holes and the gaps are disposed in the outer surface of the hollow part, between regions on which the salient poles are mounted.