A flexural in-line actuator for magnetic recording disk drives

Chainer, Timothy; Sohn, Won Joon; Sri-Jayantha, M.; Brown, D.H.; Apuzzo, N.C.

doi:10.1109/20.278817

Cited by 9 publications

(3 citation statements)

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“…Other methods using a bearing-less pivot have been described in numerous patents (Lawson 2003;Heath 1996;Schuize 1994). Flexural pivot for use in hard disc drive was investigated by He (2003) and Chainer (1991). Although the intend proposed by the above authors was to provide a lower friction torque pivot and to eliminate the need for ball bearings for cost reduction.…”

Section: Introductionmentioning

confidence: 99%

Hinge pivot for disk drive

Liu

Lim

2005

Microsyst Technol

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This paper discusses the findings of a hinge pivot for use in hard disk drives (HDD). The actuator assembly in a HDD is supported by a pivot cartridge and controlled by a servo system to perform seek and track following operations for data recording. The cartridge is composed of a pair of pre-loaded ball bearings. Due to the demand for thin hard disk drives and hence, the need to reduce the height of the actuator assembly, a hinge pivot is proposed to replace the set of bearings. The shaft of the pivot is connected to the sleeve with thin hinges made of ultra-high heat-resistant polyamide film, such as Upilex. Measurement showed that the hinge pivot did not exhibit the nonlinear effects during low frequency actuation, such was inherent for ball bearing pivots. Experiment also showed that at least a million life cycles can be achieved without any performance degradation.

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Section: Introductionmentioning

confidence: 99%

Hinge pivot for disk drive

Liu

Lim

2005

Microsyst Technol

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“…Previously an actuator comprised of parallel pair of steel leaf springs which support a moving coil in a voice coil motor (VCM) was proposed by IBM Research Division, Chainer et al (1989Chainer et al ( , 1991 and Sri-Jayantha et al (1991). In the design, the actuator translation is produced by the bending of the flexible ends.…”

Section: Introductionmentioning

confidence: 99%

Design of flexural pivot for use in hard disc drive actuator

Hua

et al. 2003

Microsystem Technologies

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A cross leaf flexural pivot is proposed and designed for use in disc drive actuator to replace the currently used ball bearing system. The static and dynamic performances of the proposed design are investigated using finite element analysis. It is shown that flexural pivot can achieve a translatory stiffness comparable to currently used ball bearing. The tilt stiffness is lower than that of ball bearing. The design is prototyped and the life cycling test shows that the prototype can work for more than 3 million life cycles without any failure. Our experimental results show that the single-stage servo loop using the flexural pivot can achieve the performances of open-loop bandwidth of 630 Hz and closed loop bandwidth of 1100 Hz, with phase margin of 60°and gain margin of 6.6 dB. When attaching an actuated suspension to from a dual stage servo loop, we show that the performances as open-loop bandwidth of 1700 Hz with the phase margin of 45°and gain margin of 7 dB. IntroductionTo stay competitive in the highly volatile HDD industry, cost cutting is an attractive and viable option. Currently ball bearings are used in hard disc drives to provide rotational mechanism. Ball bearings operate with friction and damping, causing non-linearity in the actuator and therefore make the position control more difficult, Prater (1995) and Liu et al. (2000). Flexure bearings, on the other hand, are simpler in structure and therefore is potential for low cost compare with the current ball bearing systems. The objective of the research involved in this paper is thus to design a flexural pivot, which can replace the bearing currently used in hard disc drives without sacrificing the performance.Previously an actuator comprised of parallel pair of steel leaf springs which support a moving coil in a voice coil motor (VCM) was proposed by IBM Research Division, Chainer et al. (1989 and Sri-Jayantha et al. (1991). In the design, the actuator translation is produced by the bending of the flexible ends. The motion generated without any metal contact typical of conventional ball bearing based actuator systems used in disc files. Therefore, the system does not generate any particulate debris or require any lubrication, resulting in very clean operation. The absence of metal contact eliminates stictional forces, offering potential for very fine motion control. In addition, the translatory motion of the actuator produces a small ±1.0°skew angle at the recording head, much lower than conventional rotary designs. The investigation also indicates that the presence of the significant bias forces and low-frequency modes are clearly inevitable in a flexural actuator. In the work reported by He et al. (2002), the disk drive actuator can be designed with a slant suspension, which achieves ±2.0°skew angle. The dynamic performance of the slanted actuator does not change significantly to the actuator assembly without slanting the suspension. However, as the design of the small skew actuator needs to increase the actuator arm length, this will cause the reso...

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“…The length of the arm/suspension assembly has been increased about 20%, which leads to 20-30% drop of resonance frequencies of the system compared to a conventional design. A parallel link mechanism has been proposed by Seagate Technology to reduce the skew angle variation [5], but the link position and dimensions have yet to be optimized. More recently, a MEMS based rotary actuator was presented for skew angle compensation of HDDs [6].…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Minimum Skew Angle Actuation for Hard Disk Drives

Mou

Chan

2016

MATEC Web of Conferences

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Abstract. The utilization of voice coil motor (VCM) rotary actuator in hard disk drives (HDDs) results in skew angles between the read/write head and disk rotation direction. The system performance and achievable capacity of hard disk drives are excessively sensitive to the skew angle [1][2][3]. The difference in skew angle, between the ID to the OD can be as large as more than 30 degrees in conventional 3.5" and 2.5" VCM actuated HDDs. This paper presents three mechanisms, namely, a slant arm/suspension mechanism, a guider track mechanism, and a 4 link mechanism which can be designed to achieve minimum skew angle actuations for hard disk drives. The slant arm/suspension mechanism reduces the skew angle to ± 2 degrees in rotary actuated systems. The guider track mechanism further achieves the skew angle as zero degree theoretically. As an approximation of the guider track mechanism, the 4 link actuation mechanism reduces the skew angle to 0.4 degree. Their system dynamic behaviors are studied numerically using finite element modelling. Some of designs are prototyped and experimentally investigated.

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A flexural in-line actuator for magnetic recording disk drives

Cited by 9 publications

References 1 publication

Hinge pivot for disk drive

Hinge pivot for disk drive

Design of flexural pivot for use in hard disc drive actuator

Mechanisms of Minimum Skew Angle Actuation for Hard Disk Drives

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