JPH0496637A - Damping electrical rotating machine - Google Patents

Abstract

PURPOSE:To obtain a damping electrical rotating machine for supporting a stator so that a vibration generated in the stator is not transmitted to a frame, by sticking a visco-elastic body to an elastic supporting member, when an apparatus is operated by a thyristor variable speed control system, etc. CONSTITUTION:A stator composed of a stator core 2, an outside space plate 3, a core frame 4, a longitudinal rib 4a, annulus rings 4b, 4c, a ring key 5, a stator keep plate 6, a stator winding 7, etc., is elastically supported by a frame 8 via a spring rod device 11. This spring rod device 11 is composed of a conventional spring rod 10 and a visco-elastic body 12 consisting of e.g. rubber, resin, etc., stuck round this spring rod 10 and, when the visco-elastic body is added to the spring rod, the resonance amplification of the spring rod itself can be suppressed so that it is possible to interrupt the vibration of the stator of a motor driven at a variable speed by a thyristor control to obtain a motor of small frame vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a large rotating electric machine, and particularly to a stator structure that reduces vibration.

(Prior Art) FIG. 9 shows an example of the structure of a stator of a conventional large electric motor. This stator consists of a stator core 2. Outer spacing plates 3 are placed at both ends of the stator core 2 to press the core, and the outer spacing plates 3 are further compressed in the axial direction, and a ring key 5 is attached to the core frame 4.
It consists of a stator holding plate 6 that is fixed with a core frame 4.
consists of a plurality of vertical ribs 4a arranged in the circumferential direction and a plurality of circular rings 4b and 4c arranged in the axial direction.

Here, 4b is a ring disposed at both ends in the axial direction,
4c is a circular ring placed in the middle. Usually, these rings 4b, 4c and the vertical ribs 4a are firmly joined by welding at the joints. A coil slot (not shown) is provided on the inner cylindrical surface of the stator core 2, and the stator winding 7 is provided within the coil slot.

In the stator configured as described above, the ring 4b is supported by being joined by welding to the ring-shaped shelf plate 9a firmly fixed to the frame 8, or the stator is supported by the ring 4b being joined by welding to the ring-shaped shelf plate 9a firmly fixed to the frame 8, or as shown in FIG. The ring 4b is welded to the fence plate 9a via a spring rod lO arranged on the same circle as the iron core frame 4, and the joint positions are at different positions in the axial direction (the ring 4b and the fence plate 9a). By doing so, the stator is elastically supported with respect to the frame by utilizing the spring effect of the spring rod 10.

Note that the rotor 1 is rotatably supported by a bearing (not shown).

(Problem to be solved by the invention) In normal operating conditions, the stator core 2 of the electric motor is
It deforms and vibrates due to the action of magnetic force generated in a magnetic circuit consisting of a rotor and stator.

This vibration is twice the power frequency and causes the core frame 4 supporting the stator to vibrate, and the shelf plate 9 is transmitted through the ring 4b.
a and causes the frame 8 to vibrate.

Further, in the elastic support system using the spring rod 10 shown in FIG. 10, sufficient vibration isolation can be realized by appropriately determining the spring constant of the spring rod 10.

However, in recent years, there has been an increase in the number of systems in which electric motors are operated at variable speeds from low speed ranges to high speed ranges using variable speed control systems that utilize thyristor elements. By the way, in this type of power supply using a thyristor element, the voltage waveform is distorted from a sine wave, and therefore contains many high-order harmonics.

The stator core is also deformed and vibrated by the action of the magnetic force due to the harmonics, which is transmitted to the frame 8 and generates large vibration noise. When the stator core 2 is elastically supported using a spring bar 10, vibration transmission due to the fundamental wave magnetic force of the power source can be blocked, but vibrations due to high-order harmonic magnetic force are Resonating with the vibration frequency, unexpectedly large vibrations are transmitted to the frame 8. Particularly in variable speed operation, since the frequency of the high-magnetic magnetic force changes in accordance with the operating frequency, an increase in vibration transmission due to resonance with the natural frequency of the spring shaft itself becomes an unavoidable problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vibration-suppressing rotating electric machine that supports a stator so that vibrations generated in the stator are not transmitted to the frame when operated by a thyristor variable speed control method or the like; [Structure of the Invention] (Means for Solving the Problem) The present invention provides for a stator core fixed to a core frame to be attached to a frame via elastic support members extending in the axial direction and disposed on the circumference. In a vibration-damping rotating electrical machine that is elastically supported by
A viscoelastic body is fixed to an elastic support member.

(Function) By elastically supporting the stator core, the fundamental power frequency can be suppressed by fixation, and the stator core can be supported on the frame with low vibration over the entire frequency range.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a main part of an embodiment of the present invention.

In FIG. 1, 1 is a rotor, 2 is a stator core, 3 is an outer spacer plate, 4 is a core frame, 4a is a vertical rib, and 4b.

4c is a circular ring, 5 is a ring key, 6 is a stator holding plate, 7
8 is a stator winding, 8 is a frame, and 9a is a shelf board, which has the same structure as that of the conventional electric motor described above, and includes a stator core 2, an outer spacer plate 3. The stator, which is composed of a core frame 4, vertical ribs 4a, rings 4b, 4c, a ring key 5, a stator holding plate 6, a stator winding 7, etc., is elastically supported by a frame 8 via a spring rod device 11. Ru.

This spring rod device 11 includes the above-described conventional spring rod 10 and this spring rod 10 as shown in FIG.
A viscoelastic body 12 made of, for example, rubber or resin is fixed around the spring bar 10 to improve the damping effect on the natural vibration of the spring bar 10 itself.

The stator is a spring rod 10 of a spring rod device 111.
It is elastically supported by the frame 8 by firmly joining the end portions to the rings 4a, 4b by welding or the like, and by firmly joining the intermediate portions to the shelf plates 9a, 9a by welding or the like.

Next, the operation of the embodiment configured as above will be explained. FIG. 3 shows each component as a vibration model. 20 is a fixed portion equivalent to the frame 8; 21 is a cantilever beam equivalent to the spring rod 10; and 22 is a weight equivalent to the stator core 2. In such a vibration system, the bending spring constant of the five cantilever beams is KKgf/awe
, when the weight of the weight 22 is IKgf, the natural frequency of this system is fn=±×2π! -! −L (Hz). Here, g is the gravity acceleration. Then, for the weight 22, F=cos2πf1
When an excitation force t is applied, the transmission rate τ of the force transmitted to the fixed part 20 is ideally the fourth in the relationship between f and f□.
It will look like the figure. Therefore, by shortening f, f/fn
If the spring constant K is selected so as to be sufficiently large, sufficient anti-vibration support will normally be obtained. However, in the vibration model of FIG.

As shown in FIGS. 5(a) and 5(b), the cantilever beam deforms into a higher-order vibration mode. In this case, the vibration transmissibility curve is
As shown in FIG. 6, there are places where the vibration transmissibility becomes significantly high due to higher-order vibration modes.

In an electric motor operated under thyristor control, weight 2
The force acting on 2 is F=A, cos 2xf, t+A, cos 4πfit
+A3cos 6πf, t+-, and there is an excitation force with a frequency that is an integral multiple of fl, and these change,
This corresponds to the point where the vibration transmissibility due to the higher-order vibration moat increases as shown in FIG.

Large vibrations will be transmitted to the frame 8.

On the other hand, when a viscoelastic body is fixed to a spring rod as in the present invention, the viscoelastic body absorbs vibration energy when the spring rod is bent, so the vibration transmission rate does not become so large even during resonance. , as shown in FIG. 7, and it can be seen that vibration transmission can be sufficiently prevented even in an electric motor operated at variable speed under thyristor control.

Therefore, in the conventional configuration, the vibration transmission rate increases due to the high-order vibration mode of the spring rod, and the vibration transmission to the frame is large, but as in the above embodiment, a viscoelastic body is added to the spring rod. By doing so, the resonance amplification of the spring shaft itself can be suppressed, so that the vibration of the stator of the electric motor driven at variable speed by thyristor control can be blocked, and an electric motor with small frame vibration can be obtained.

In the above-mentioned embodiment, one viscoelastic body 12 is fixed in the middle of the spring bar 10 as the spring bar device It, but as shown by the dashed line in FIG. You may also do so. Further, as shown in FIG. 8, the spring rod device 23 may be constructed of a leaf spring-like spring rod 24 having four parts in the middle, and a viscoelastic body 25 fixed to a recessed portion of the spring rod 24. good.

〔Effect of the invention〕

As explained above, according to the present invention, the stator core is elastically supported by the spring rod, and a viscoelastic body is fixed to the spring rod, thereby suppressing the resonance amplification of the higher-order motes generated in the spring rod itself. Therefore, it is possible to effectively block harmful electromagnetic vibrations generated in the stator when the stator is operated at variable speed by thyristor control or the like, thereby reducing frame vibrations and providing a vibration-suppressing rotating electric machine.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing essential parts of an embodiment of the present invention, FIG. 2 is a perspective view of a spring rod device used in an embodiment of the present invention, and FIG. 3 is a diagram for explaining the present invention in detail. Model diagram, Figure 4 is a general vibration transmissibility curve diagram of the model shown in Figure 3, and Figures 5 (a) and (b) are explanations showing the deformation state due to higher-order vibration modes of the model shown in Figure 3. Figure 6 is a general vibration transmissibility curve diagram of the higher-order vibration mode of the model shown in Figure 3, and Figure 7 is a vibration transmissibility curve of the present invention according to the higher-order vibration mode of the model shown in Figure 3. 8 is a perspective view of a spring support device used in another embodiment of the present invention, FIG. 9 is a sectional view showing a stator support portion of a conventional electric motor, and FIG. FIG. 3 is a cross-sectional view showing a stator support portion of the electric motor. 1911 Rotor 2... Stator core 4...
Iron core 7... Stator winding 8... Frame 10... Spring rod 12... Viscoelastic body (8733) Agent Patent attorney Yoshiaki Inomata (1 idiot) Figure Figure Figure Figure (a) Figure 1

Claims (1)

[Claims] In a vibration-damping rotating electrical machine in which a stator core fixed to a core frame is elastically supported on a frame via elastic support members extending in the axial direction and disposed on the circumference, the elastic support member has a viscosity. A vibration-damping rotating electric machine characterized by a fixed elastic body.