This study is devoted to evaluate the performance of a ball-type balancer system that is installed in high-speed optical disk drives. The ball-type balancer system, composed of a circular runway and free-moving balls inside, is designed for reducing radial vibrations induced by the inherent unbalance of the rotating system. A balancer system equipped with a pair of balls is considered in this study for its capability to reach possible near-elimination of radial vibrations as opposed to the serious sizing problem of a single balancing-ball system. A mathematical model is first established to describe the dynamics of the balls and rotor system. Utilizing the method of multiple scales and assuming the smallness of radial vibrations, the system dynamics on the slow time scale is represented by eight first-order autonomous differential equations, which accommodate the radial vibratory motions and ball behaviors. The steady-state solutions of these slow equations are then solved and their stability analyzed to predict settling ball positions. The residual vibrations are computed to evaluate the performance of the balancer system and then the design guidelines are distilled for engineers to design the balancer system.

Issue Section:
Technical Papers
Keywords:
vibrations, differential equations, disc drives, damping
Topics:
Disks, Dynamics (Mechanics), Rotors, Stability, Steady state, Vibration, Differential equations, Design
1.
Takashi, K., Yoshihiro, S., Yoshiaki, Y., Shozo, S., and Shigeki, M., 1998, “Disk Type Storage Device,” Japanese Patent 10,092,094.
2.
Kiyoshi, M., Kazuhiro, M., Shuichi, Y., Michio, F., Tokuaki, U., and Masaaki, K., 1997, “Disk Drive Device,” Japanese Patent 10,038,622.
3.
Takatoshi, Y., 1998, “Disk Drive Device,” Japanese Patent 10,188,465.
4.
Masaaki, K., 1998, “Disk Device,” Japanese Patent 10,208,374.
5.
Thearle
,
E. L.
,
1950
, “
Automatic Dynamic Balancers (Part 1 Leblanc Balancer)
,”
Mach. Des.
,
22
,
Sept.
, pp.
119
–
124
.
6.
Thearle
,
E. L.
,
1950
, “
Automatic Dynamic Balancers (Part 2-Ring, Pendulum, Ball Balancers)
,”
Mach. Des.
,
22
,
Oct.
, pp.
103
–
106
.
7.
Inoue
,
J.
,
Jinnouchi
,
Y.
, and
Kubo
,
S.
, “
Automatic Balancers
,”
1979
,
Trans. Jpn. Soc. Mech. Eng., Ser. C
,
49
, pp.
2142
–
2148
.
8.
Bo¨vik
,
P.
, and
Ho¨gfors
,
C.
,
1986
, “
Autobalancing of Rotors
,”
J. Sound Vib.
,
111
, pp.
429
–
440
.
9.
Jinnouchi
,
Y.
,
Araki
,
Y.
,
Inoue
,
J.
,
Ohtsuka
,
Y.
, and
Tan
,
C.
,
1993
, “
Automatic Balancer (Static Balancing and Transient Response of a Multi-Ball Balancer)
,”
Trans. Jpn. Soc. Mech. Eng., Ser. C
,
59
, pp.
79
–
84
.
10.
Tadeusz
,
M.
,
1988
, “
Position Errors Occurrence in Self Balancers Used on Rigid Rotors of Rotating Machinery
,”
Mech. Mach. Theory
,
23
, pp.
71
–
78
.
11.
Rajalingham
,
C.
, and
Rakheja
,
S.
,
1998
, “
Whirl Suppression in Hand-held Power Tool Rotors Using Guided Rolling Balancers
,”
J. Sound Vib.
,
217
, pp.
453
–
466
.
12.
Chung
,
J.
, and
Ro
,
D. S.
,
1999
, “
Dynami Analysis of an Automatic Dynamic Balancer for Rotating Mechanism
,”
J. Sound Vib.
,
228
, pp.
1035
–
1056
.
13.
Huang, Wei-Yu, Kang, Jaan-Rong, Sung, Cheng-Kuo, and Chao, Chang-Po, 2001, “An Application of Ball-Type Balancers on Radial Vibration Reduction of High-Speed Optic Disk Drives,” to appear in J. Sound Vib. .
Copyright © 2001
 by ASME
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