Vibration Analysis of a Self-Excited Vibration in a Rotor System Caused by a Ball Balancer

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Yukiko Ishida ◽  
Hideaki Niimi
Keyword(s):  
Rotational Speed ◽  
Critical Speed ◽  
Vibration Suppression ◽  
The Self ◽  
Rotor Systems ◽  
Excited Vibration ◽  
Amplitude Vibration ◽  
Speed Range ◽  
Large Amplitude Vibration ◽  
Fundamental Equations

The ball balancer has been used as a vibration suppression device in rotor systems. It has a superior characteristic that the vibration amplitude is reduced to zero theoretically at a rotational speed range higher than the critical speed. However, the ball balancer causes a self-excited vibration near the critical speed when the balls rotate in the balancer. This self-excited vibration may occur in the wide rotational speed range with a large amplitude vibration, and in such a case, escaping from it becomes difficult. In this paper, the occurrence region and the vibration characteristics of the self-excited vibration caused by the ball balancer are investigated. The nonlinear theoretical analysis is performed and a set of the fundamental equations governing the self-excited vibration is obtained. The influences of the parameters of the ball balancer, such as, the damping of the ball’s motion, the ball’s mass, and radius of the balls’ path, are explained and they are also validated experimentally.

Vibration Analysis of the Self-Excited Vibration in the Rotor System Due to Ball Balancer

2009 ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Hideaki Niimi ◽  
Yukio Ishida
Keyword(s):  
Vibration Suppression ◽  
Rotor System ◽  
The Self ◽  
Excited Vibration ◽  
Amplitude Vibration ◽  
Speed Range ◽  
Large Amplitude Vibration ◽  
Fundamental Equations ◽  
Ball Mass ◽  
Ball Motion

The ball balancer has been used as the vibration suppression device in rotor system. It has a superior characteristic that the vibration amplitude is reduced to zero at the rotational speed range higher than the major critical speed. However, the ball balancer may cause a self-excited vibration when the balls rotate in the balancer, and this self-excited vibration results in the large amplitude vibration. In this paper, the occurrence region and vibration characteristics of the self-excited vibration are investigated. The theoretical analysis is performed and a set of the fundamental equations governing the self-excited vibration is obtained. The influences of the parameters, such as, damping of the ball motion, ball mass, and radius of the ball orbit are explained. As the result, it is shown that the damping of the ball motion and the ball mass have the effect on decreasing the occurrence region of the self-excited vibration.

Efficiency Improvement of an Automatic Ball Balancer

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Yukio Ishida ◽  
Tomonori Matsuura ◽  
Xiao Long Zhang
Keyword(s):  
Critical Speed ◽  
Vibration Suppression ◽  
The Self ◽  
The Other ◽  
Efficiency Improvement ◽  
Cylindrical Chamber ◽  
Rotor Systems ◽  
Speed Range ◽  
Excited Oscillation ◽  
Inside Wall

An automatic ball balancer is a unique vibration suppression device for rotor systems. Theoretically, two balls in a cylindrical chamber of the rotor are located at the optimal positions on the opposite side to the unbalance and cancel the unbalance automatically in the super-critical speed range. However, this device is not used widely due to two malfunctions. One is the influence of friction. Due to the inevitable friction between the balls and the inside wall of the channel, the balls stop near the optimal positions and do not balance the rotor perfectly. The other is the self-excited oscillation which occurs near and above the major critical speed. The objectives of the present paper are to clarify the fundamental characteristics of a ball balancer and to introduce some simple methods to eliminate these malfunctions.

Vibration Suppression of Rotating Machinery Utilizing an Automatic Ball Balancer and Discontinuous Spring Characteristics

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Jun Liu ◽  
Yukio Ishida
Keyword(s):  
Rotational Speed ◽  
Large Amplitude ◽  
Small Amplitude ◽  
Critical Speed ◽  
Vibration Suppression ◽  
Rotating Machinery ◽  
Almost Periodic ◽  
Periodic Motions ◽  
Speed Range ◽  
Suppression Method

Automatic ball balancer is a balancing device where two balls inside a hollow rotor move to optimal rest positions automatically to eliminate unbalance. As a result, vibrations are suppressed to the zero amplitude in the rotational speed range higher than the major critical speed. However, it has the following defects. The amplitude of vibration increases in the rotational speed range lower than the major critical speed. In addition, almost periodic motions with large amplitude occur in the vicinity of the major critical speed due to the rolling of balls inside the rotor. Because of these defects, an automatic ball balancer has not been used widely. This paper proposes the vibration suppression method utilizing the discontinuous spring characteristics together with an automatic ball balancer to overcome these defects and to suppress vibration. The validity of the proposed method is confirmed theoretically, numerically, and experimentally. The results show that amplitude of vibration can be suppressed to a small amplitude in the vicinity of the major critical speed and the zero amplitude in the range higher than the major critical speed.

Vibration Suppression of Rotating Machinery Utilizing an Automatic Ball Balancer and Discontinuous Spring Characteristics

2007 ◽  
Author(s):  
Jun Liu ◽  
Yukio Ishida
Keyword(s):  
Rotational Speed ◽  
Large Amplitude ◽  
Small Amplitude ◽  
Critical Speed ◽  
Vibration Suppression ◽  
Rotating Machinery ◽  
Almost Periodic ◽  
Periodic Motions ◽  
Speed Range ◽  
Suppression Method

Automatic ball balancer is a balancing device where two balls inside a hollow rotor move to optimal rest positions automatically to eliminate unbalance. As the result, vibrations are suppressed to a small amplitude or a zero amplitude in the rotational speed range higher than the major critical speed. However, it has the following defects. The amplitude of vibration increases in the rotational speed range lower than the major critical speed. In addition, almost periodic motions with large amplitude occur due to the rolling of balls inside the rotor in the vicinity of the major critical speed. Due to those defects, the automatic ball balancer has not been used widely. This paper proposes the vibration suppression method utilizing the discontinuous spring characteristics together with an automatic ball balancer to suppress vibration and to overcome these defects of the automatic ball balancer. The validity of proposed method is confirmed theoretically, numerically and experimentally. The results show that amplitude of vibration can be suppressed to a small amplitude in the vicinity of the major critical speed and the zero amplitude in the range higher than the major critical speed.

scholarly journals Suppression of Self-Excited Vibrations in Rotating Machinery Utilizing Leaf Springs

2019 ◽  
pp. 599-608
Author(s):  
Chang Wang ◽  
Jun Liu ◽  
Zhiwei Luo
Keyword(s):  
Dry Friction ◽  
Critical Speed ◽  
Rotating Machinery ◽  
The Self ◽  
Internal Damping ◽  
Structural Damping ◽  
Leaf Springs ◽  
Excited Vibration ◽  
Hysteretic Damping ◽  
Theoretical Analyses

When rotating machinery is operated above the major critical speed, self-excited vibrations appear due to internal friction of the shaft. Internal frictions are classified into hysteretic damping due to the friction in the shaft material and structural damping due to the dry friction between the shaft and the mounted elements. In this paper, a method to suppress the self-excited vibration using leaf springs are proposed. The structural damping is considered as the internal damping. The characteristics of a rotor with leaf springs are investigated systematically by using simulative and theoretical analyses. The validity of the proposed method is also proved by experiments.

Free Vibration of Uniform, Flexible, Cylindrical Shell Rotors

1999 ◽  
Author(s):  
Fei-Yue Wang ◽  
Albert C. J. Luo
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Rotational Speed ◽  
Rotation Speed ◽  
Isotope Separation ◽  
Critical Speeds ◽  
Amplitude Vibration ◽  
Large Amplitude Vibration ◽  
Very High ◽  
Good Agreement

Abstract The critical speeds and responses of uniform, flexible, cylindrical rotors are predicted by use of the Riccati transfer matrix method. The critical speeds are also measured experimentally. The computational and experimental results are in good agreement. The balancing of two cylindrical shell rotors is completed. For the two balanced rotors, no large amplitude vibration occur when the operating, rotational speed passes through critical speeds, and that rotation speed can arrive to a very high value to meet the requirement of isotope separation in engineering.

scholarly journals Self-excited vibration of whole vehicle with multiple limit cycles induced by shimmy of front wheels

2019 ◽  
Vol 39 (4) ◽  
pp. 1052-1064 ◽  
Author(s):  
Daogao Wei ◽  
Wenhao Zhai ◽  
Yingjie Zhu ◽  
GenSheng Jiang ◽  
Andong Yin ◽  
...  
Keyword(s):  
Limit Cycles ◽  
Lateral Force ◽  
Steering System ◽  
Front Wheel ◽  
The Self ◽  
Vehicle Speed ◽  
Bifurcation Theorem ◽  
Excited Vibration ◽  
Speed Range ◽  
Existence And Stability

Front wheel shimmy may induce the self-excited vibration of whole vehicle with multiple limit cycles. This kind of shimmy is difficult to control and can do great harm to the vehicle. In order to obtain the mechanism of this phenomenon, a 7-DOF dynamic model of whole vehicle self-excited vibration induced by the shimmy of front wheels which take the nonlinear factor of tire lateral force and the dry friction force in suspension and steering system into consideration was established. By using Hopf bifurcation theorem and central manifold theorem, the existence and stability of limit cycles are qualitatively determined. By means of numerical analysis, the self-excited vibration with multiple limit cycles is found. The results show that in the speed range of 50–185 km/h, front wheels shimmy induced the self-excited vibration of whole vehicle and the amplitude of system’s vibration decreases with the increase of vehicle speed; in the speed range of 50–83 km/h and 149–185 km/h, the self-excited vibration with multiple limit cycles occurs; in the speed range of 83–149 km/h, the self-excited vibration with single limit cycle occurs.

A Lower Pad Adjustable Bearing Reducing Vibration Response of Rotor Systems During Acceleration

2019 ◽  
Author(s):  
Lei Zhang ◽  
Hua Xu ◽  
Shenglun Zhang ◽  
Shiyuan Pei
Keyword(s):  
Critical Speed ◽  
Vibration Suppression ◽  
Load Condition ◽  
Element Model ◽  
Rotor System ◽  
Vibration Response ◽  
Resonance Amplitude ◽  
Suppression Effect ◽  
Rotor Systems ◽  
Light Load

Abstract A lower pad movable bearing is proposed which has the ability to change the lubricating performance of the journal bearing. The structure and working principle of the adjustable bearing are introduced. This bearing can adjust the working status of the rotor system by changing the position of the bearing pad and reduces the vibration amplitude of rotor. In this paper, a simple rotor bearing finite element model is used to study the vibration response of the rotor system. Through research, it is found that larger ellipticity can effectively reduce the amplitude of the rotor when the rotor speed is running at a certain speed away from the critical speed, and the vibration suppression effect can reach 67%. When the rotor passes the critical speed, reducing the ellipticity can significantly reduce the resonance amplitude of the rotor, and the vibration suppression effect reaches about 37%. In addition, when the rotational speed increases to twice the critical speed, the oil film oscillation occurs under light load condition, which can be suppressed by reducing the ellipticity. Adjustable bearing can then be proposed to adaptively improve the vibration of the rotor system based on the rotor speeds.

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