JPS5868533A - Balancing method for elastic rotor - Google Patents

Abstract

PURPOSE:To reduce imbalance generated in the rotor automatically by receiving a liquefied substance, which is liquefied at a fixed temperature or higher and solidified at a fixed temperature or lower, into a hollow section formed to the rotor, sufficiently distributing the liquefied substance into the hollow section and solidifying said substance. CONSTITUTION:The elastic rotor consists of a rotor proper 8 and a journal 9, and is supported by bearings 10. The hollow section 11 is shaped to said rotor proper 8, and the liqueified substance 12, which is liqueified at a fixed temperature or higher and solidified at a fixed temperature or lower, is received into the hollow section. When the elastic rotor is turned and exceeds critical speed, the rotor is deflected in the direction opposite to imbalance force A, and the center Os is displaced in the direction opposite to imbalance force A. In this case, the liquefied substance 12 is also distributed thickly in the direction opposite to imbalance force A, centrifugal force B by the liquefied substance 12 works in the direction opposite to imbalance force A, and imbalance force A is reduced. Accordingly, the liquefied substance 12 is solidified, resonant amplitude is decreased at critical speed, and the rotor is balanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of balancing an elastic rotor that is operated over a critical speed, and automatically reduces unbalance remaining in the rotor to reduce unbalance vibration.
The present invention relates to a virance method for an elastic rotor that allows the rotor to operate stably.

Due to performance requirements, there is a trend toward smaller and lighter rotating machines in Zhongcheng. This means that the speed of the rotor of a rotating machine increases. As shown in FIG. 1, the rotor is generally composed of a rotor body 1 and a journal 2, and is supported by bearings 3 for rotation. Rotating bodies (not shown) such as two blades, an impeller, and an armature are attached to the rotor body 1, but due to the processing accuracy of ff9 and assembly accuracy, there are some deficiencies. Because this difference 4 exists,
When the rotor body 1 is rotated at high speed, friction vibration occurs. The vibration amplitude changes with respect to the rotational speed N as shown in FIG. The point where the amplitude peaks is the critical speed N
This is a resonance called a r.

Since the rotor rotating at high speed is operated passing through this critical speed N, the amplitude at the critical speed must be kept sufficiently within an allowable value.

In order to reduce the vibration, the unbalance 4 should be made as small as possible. Usually, in order to reduce the unbalance 4, a correction weight 5 is added as shown in FIG. 3, or the unbalance itself is deleted. The size and position of the correction violet in this case are determined by a special method called the elastic rotor nosing method.

Traditional methods measure rotor vibrations at several points and use that data to perform special calculations to determine the size and location of the correction violet. For this purpose, special measuring equipment and electronic computer systems are required, and the work of balancing the elastic rotor is generally large-scale and difficult.

On the other hand, the unbalanced vibration of the rotor increases with the rotational speed N.
The rotor body l responds as shown in the figure, but at that time the rotor main body l moves along the line O-
With respect to 0, the center line of the rotor body l bends and swings in an arched manner, and the center line of the rotor body l becomes K such as 0-0m-0. Rotor body 1
As shown in (a) and Φ in FIG. 2, the center 0■ of the critical speed N0 has a different positional relationship with the non-comb direction A before and after the critical speed N0. At rotation speeds lower than critical speeds N and t, the rotor bends and swings around in the direction of the unbalanced person.
If the critical speed N, t is exceeded, the skew A will break and the liquid contained in the rotating hollow container will tend to become concentric with the center of rotation. In FIG. 5(a), liquid 7 gold is placed in the hollow container 6, and the hollow container 6 is placed around the 0 point.
When , the liquid 7 creates a free surface of equal radius from the zero point.

25th! If the center of the rotor is misaligned and is in the opposite direction to A, as shown in (b) of J, and there is liquid inside the rotor, a situation like that shown in Figure 5) will be created.

Since the liquid tries to be concentric with the rotation line O-0 on the line connecting the bearings, it is distributed thickly on the side opposite to the unbalanced one as shown in the figure. As a result, the flaw caused by the liquid occurs in the direction B, which acts to cancel the flaw A.

It is an object of the present invention to utilize this phenomenon to provide a balancing method that is simpler and more reliable than the conventional parallax method for an elastic rotor.

The present invention combines the whirling characteristics of the elastic rotor after the critical speed M, particularly the characteristics after passing the critical speed, and the behavior of the liquid in the rotating hollow container.

An embodiment of the present invention will be described below with reference to FIG. In the figure, the rotor is the rotor body 8. It is composed of a journal 9 and supported by a bearing 10, and is the same as the rotor shown in FIG. The hollow portion 11 is formed at an arbitrary position, an arbitrary size, and an arbitrary length in the rotor main body 8, and its outer diameter surface is concentric with the rotation center 0-O of the rotor. The liquid substance 12 is placed in the hollow part 11 so that a free surface exists.

When this rotor is rotated, the vibration changes as shown in the curve @b in FIG. 7 as the rotor rotates. In Figure 7, the song @a is
This is the vibration response caused by the gap 13 when the liquid substance 12 is not put into the hollow part 11. At a rotation speed just before the critical speed, the rotor deflects in the direction of the unbalanced rotor, as shown in FIG. 5(a), and its center 01 deviates from the rotation center O in the unbalanced direction. At this time, the liquid substance 12 is moved into the hollow part 1 so that it has an equal radius around the rotation center O due to centrifugal force.
Distributed on the inner surface of 1. Since the liquid substance 12 is thickly distributed in the uneven C6 case A, the centrifugal force B generated thereby is in the same direction as the uneven direction A, as shown in FIG. 5(a). Therefore, since the unbalance is increased, the vibration of the rotor increases compared to the case where there is no liquid substance 12.

However, if the critical speed is exceeded, as shown in Figure 5 (b),
The rotor deflects in the opposite direction to the unbalance A, and the rotor 0 center O1 shifts in the opposite direction to the unbalance A. In particular, the liquid substance 12 is also distributed thickly in the direction opposite to the mismatch A.

The centrifugal force B caused by the liquid material 12 acts in the opposite direction to the unbalanced force, and thus acts to reduce the unbalance A. The unbalanced vibration at this time, as shown in the song @b in Fig. 7, is also lower than the song iia yo ji when there is no liquid substance 12.

The shape of the liquid substance 12 when the hole is in this state is frozen by some method.

In this state, when the rotational speed is lowered, the actual inconsistency is reduced, so the vibration response like that in song mC is not generated, and the resonance amplitude at the critical speed is reduced.

This means that the balance between the knob and the elastic rotor has been achieved.

For this purpose, the liquid substance 12 needs to be fluid only during the balancing operation and solidify during actual rotor operation. Such substances include
For example, there are gelastec that is heated and liquefied, hardening adhesives, and molten metals.
There are low melting point metals.

It is preferable that this kind of substance sealed in the hollow part has the same density as the rotor. In this case, a considerable balance effect can be expected with almost no vibration occurring.

For example, in the case of a steel rotor, Sn (density 7.3g
/cm", melting point 232C) can be used as a base, and a low melting point alloy can be used, which is made by suitably blending PB, J3i, etc. and matching the density.The melting point is 50C, so this can be used as a base material for hollow part 1.
1, the rotor is rotated at a rotation speed well above the dangerous speed, and heat is applied from the outside or inside to liquefy it. After this substance is sufficiently distributed on the inner surface of the hollow portion, heating is performed. FIG. 8 shows an example of the present invention. 14 is a rotor portion in which a liquid substance 12 is sealed.

According to the present invention, balance and balance can be automatically performed without requiring vibration measurement unlike conventional balances.

[Brief explanation of drawings]

Fig. 1 is a front view of the rotor, Fig. 2 is a vibration response diagram of the elastic rotor, (a) and Φ) are cross-sectional views showing the unbalance direction and rotor deflection direction before and after the critical speed, and Fig. 3 Figure 4 is a front view of the nine rotors using the conventional balancing method, Figure 4 is a front view showing the deflection of the rotor during unsteady imaging, Figure 5 is a cross-sectional view showing the distribution of liquid in the hollow container, FIG. 6 is a front sectional view showing an embodiment of the elastic rotor balancing method of the present invention;
FIG. 7 is a rotor vibration response diagram showing the balancing effect when the present invention is implemented, and FIG. 8 is a front sectional view showing another embodiment of the elastic rotor balancing method of the present invention. 8...Rotor body, 9...Journal, lO...
Bearing, 11...Hollow part, 12...Liquid substance, 13.
...Unbalance, 14...Hollow container. Number of revolutions〃￥i 3 Figure 4 Figure 5 (Ku)
(b) Atsushizuzu Punishment 7th Eye [1 Shinyun Ishi (N) Sword S Figure

Claims (1)

[Claims] A hollow part is provided inside the rotor body so that its inner surface is concentric with the center of rotation, or a hollow container having a similar structure is provided outside the rotor main body, and inside these hollow parts,
A liquid substance that becomes liquid above a certain temperature and becomes solid below this temperature is sealed, the rotor is rotated at a rotation speed that sufficiently exceeds the dangerous speed of the rotor, the liquid substance is turned into a liquid by heating, etc., and the liquid substance is transferred to the hollow part. A method of balancing an elastic rotor in which the characteristics are sufficiently distributed on the inner surface, then the temperature is lowered, the liquid substance solidifies, and the rotor is stopped.