JPH0626464B2 - Casting rotor - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a cast rotor formed by casting end rings at both ends of a rotor core by casting aluminum.

[Technical background of the invention]

2. Description of the Related Art Conventionally, for example, a casting rotor used in a high-speed rotating electric machine has a rotor core 1 formed by laminating magnetic steel sheets with a predetermined thickness as shown in FIG. And the cylindrical end rings 4 are integrally formed at both ends (only one side is shown in the figure) of the rotor core 1 by casting aluminum. The rotary shaft 5 is press-fitted into the rotor core 1, and the reinforcing ring 6 made of a non-magnetic steel material, for example, high chrome nickel steel, is shrink-fitted on the outer peripheral portion of the end ring 4 and fixed by screws 7. .

[Problems of background technology]

However, in the case of the above configuration, the end ring 4
Has a large exposed surface area in order to secure its cross-sectional area and to provide a centrifugal force resistant structure. Therefore, especially when the rotor rotates at a high speed, there is a problem that the friction loss between the surface of the end ring 4 and the surrounding fluid is large and the rotation efficiency is reduced.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object thereof is to reduce the friction loss between the end ring portion and the surrounding fluid to improve the rotation efficiency, and to provide a centrifugal force resistant structure with a simple configuration. It is to provide a casting rotor that can be.

[Outline of Invention]

In order to achieve the above object, the present invention has an end formed by stacking non-magnetic steel plates having a hole portion having a size larger than an opening portion of a slot in the rotor core at both ends of the rotor core by shifting the angle. The ring core is arranged, and the end ring is formed by casting aluminum into the hole of the end ring core and filling it. Thus, it is characterized in that the exposed surface area of the end ring portion is reduced.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. First, in FIG. 1, reference numeral 11 denotes a rotor iron core formed by laminating magnetic steel plates to a predetermined thickness. As shown in FIG. 3, a shaft insertion hole 12 is formed in the central portion and a large number of peripheral portions are provided. The slot 13 is formed. Reference numeral 14 is an end ring iron core arranged at both ends of the rotor iron core 11, which is formed by laminating non-magnetic steel plates 14a with a predetermined thickness as shown in FIG. The non-magnetic steel plate 14
a is a shaft insertion hole 15 at the center as shown in FIG.
And a plurality of substantially fan-shaped hole portions 16 (in this case, holes each having a size of about three openings of the slots 13) larger in size than the openings of the slots 13. There is. In this case, the end ring iron core 14 is in a laminated form in which the hole 16 does not close the opening of the slot 13 and the non-magnetic steel plate 14a has a different angle in the hole 16 in the middle. Reference numeral 17 denotes a rotor bar as a secondary conductor filled in the slot 13 of the rotor core 11. Reference numeral 18 denotes an end ring which is continuously filled with the rotor bar 17 in the hole portion 16 of the end ring iron core 14 and which projects slightly annularly from the end surface of the end ring iron core 14. The rotor bar 17 and the end ring 18 are integrally formed by casting aluminum as shown in FIG. Reference numeral 19 denotes a rotary shaft, which is press-fitted into the shaft insertion holes 15 and 12 of the end ring iron core 14 and the rotor iron core 11.

Here, the casting rotor of the present embodiment and the casting rotor of the conventional configuration have the same specifications, and the surface area of the end ring portion will be compared with reference to FIGS. 5 and 6. Now
The outer diameter of the end ring (the outer diameter of the end ring iron core 14 in FIG. 5) is D ₁ , the inner diameter of the end ring is D ₂ , the outer diameter of the rotating shaft is D ₃ , and the rotor core of the end ring is Let L ₁ be the projecting dimension (corresponding to the laminated thickness dimension of the end ring iron core 14 in FIG. 5) from the end face. Further, in FIG. 5, assuming that the projecting dimension of the end ring 18 from the end surface of the end ring iron core 14 is L ₂ , the surface area A ′ of the end ring portion of the conventional structure and the surface area A of the end ring portion of this embodiment are as follows. It is represented by a formula. That is, A ′ = π (D ₁ + D ₂ + D ₃ ) L ₁ + (π / 4) D ₁ ² A = πD ₁ L ₁ + (π / 4) D ₁ ² + π (D ₁ + D ₂ + D ₃ ) L ₂ Here, taking L ₁ >> L ₂ into consideration and taking the difference between them, A′−A = π (D ₂ + D ₃ ) L ₁ −π (D ₁ + D ₂ + D ₃ ) L ₂ ≈π (D ₂ + D ₃ ) L ₁ and therefore the surface area of the end ring portion of this embodiment is greatly reduced compared to the conventional configuration.

Further, generally, in a rotating body, friction loss occurs due to friction between the surface of the rotating body and the surrounding fluid, and this is proportional to the surface area of the rotating body and the exponential power of the number of revolutions. That is, in a high-speed rotating body, it is known that the surface area, in particular, greatly affects the friction loss and thus the rotation efficiency.
Here, the friction loss of the end ring portion of the configuration of the present embodiment and the conventional configuration will be compared with reference to FIGS. 5 and 6.

Now, assuming that the friction loss of the end ring portion is Lf [KW], this friction loss Lf is the end surface (side surface) friction loss L in this case.
It is divided into fs and the inner and outer peripheral surface friction loss Lf _0, which are respectively expressed by the following equations. ^{That, Lfs = 2.68 × 10 -7 γn} 2.8 (D 0/2) 4.6 ν 0.2 Lf o = 1.39 × 10 -8 γl 0 D 0 3.76 n 2.76 ν -0.24 × S
^-0.24 where n: number of revolutions [rpm] l ₀ : axial length of end ring part [m] D ₀ : diameter of target cylinder [m] S: rotation with inner circumference of end ring Distance from shaft outer surface [m
Γ: specific gravity of surrounding fluid [Kg / m ³ ] ν: kinematic viscosity coefficient of surrounding fluid [m ² / s], and suffix 1 in the conventional case, suffix 2 in the present embodiment The respective friction losses are shown below. That is, the conventional _{case, Lf 1 = Lfs 1 + Lf} 0 1 = {2.68 × 10 -7 γn 2.8 ν 0.2 (D 1/2) 4.6} + {1.39 × 10 -8 γn 2.76 ν 0.24 S -0.24 × L 1 ^{_{D 1 3.76 + L 1 D 2}} 3.76 + L 1 D 3 3.76)} in this _{embodiment, Lf 2 = Lfs 2 + Lf} 0 2 = {2.68 × 10 -7 γn 2.8 ν 0.2 (D 1/2) 4.6} + [ 1.39 × 10 ^-8 γn ^2.76 ν ^0.24 S ^-0.24 {(L ₁ +
L ₂ ) D ₁ ^3.76 + L ₂ D ₂ ^3.76 }] Here, when L ₁ >> L ₂ is taken into consideration and the difference between Lf ₁ and Lf ₂ is taken, Lf ₁ −Lf ₂ = 1.39 × 10 ⁻⁸ γn ^2.76 ν ^0.24 S ^-0.24 × L
₁ become ^{_{(D 2 3.76 + D 3 3.76}} ). And now, L ₁ = 0.1 [m], ν = 0.175 × 10 ⁻⁴ [m ² / s] (40
℃) D ₂ = 0.45 [m], n = 15000 [rpm] D ₃ = 0.3 [m], γ = 1.091 [Kg / m ³ ] (40 ℃) S = 0.01 [m], Lf ₁ − Lf ₂ ≈7 [KW]. Therefore,
According to the present embodiment, the friction loss of the end ring portion can be significantly reduced as compared with the conventional configuration, and thus the rotation efficiency can be improved.

Further, according to the present embodiment, the special reinforcing ring 6 for centrifugal force, which is conventionally required, is not required, and the rotor core 11 is simply used.
The end ring iron cores 14 may be disposed at both ends of the end rings 18 and the end rings 18 may be formed by casting aluminum, and the end rings 18 can be easily manufactured and have a simple structure. Furthermore, since a frictional force that restrains the axial extension of the end ring 18 is generated between the end ring 18 and the end ring iron core 14, it is not necessary to consider the extension of the end ring 18. It can have a strong structure.

〔The invention's effect〕

As is clear from the above description, the present invention can reduce the exposed surface area of the end ring portion, so that the friction loss with the surrounding fluid can be reduced and the rotation efficiency can be improved. This has an excellent effect that a force structure can be obtained.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is a vertical sectional side view of the whole, and FIG. 2 is a perspective view of an essential part shown by cutting away a rotary shaft. , FIG. 3 is a front view of a rotor core, FIG. 4 is a front view of an end ring core, FIG. 5 is an enlarged vertical side view of a main part, and FIG. 6 is a conventional configuration corresponding to FIG. It is a figure. In the drawing, 11 is a rotor core, 13 is a slot, 14 is an end ring core, 16 is a hole, 17 is a rotor bar (secondary conductor), and 18 is an end ring.

Claims (1)

[Claims] 1. A rotor core, wherein a secondary conductor is formed in a slot, and end rings are integrally formed at both ends of the rotor core by casting aluminum, respectively. , The non-magnetic steel plate having a hole larger in size than the opening of the slot, the iron core for an end ring, which is formed by stacking at a different angle, is arranged, and the aluminum is cast into the hole of the iron core for an end ring. A casting rotor characterized by being filled to form an end ring.