MINEBEA Technical Conference HDD Spindle Motor & Bearing - - PDF document

MINEBEA

Technical Conference

～HDD Spindle Motor & Bearing～

March 24, 2000

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１．HDD Spindle Motor Business - Current Prospect ２．RO Bearing Motor - Performance and Advantage ３．Fluid Dynamic Bearing - Minebea Strategy ４．Fluid Dynamic Bearing - Impact to Ball Bearing Business ５．RO Bearing - Future Application ６．Minebea Production Support and It’s Organization ７．Summary Contents

In accordance with the table of contents, I would like to provide you with a technical profile of Minebea's businesses concerning HDD spindle motors and bearings including fluid dynamic bearings.

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2 2001 CQ3 5,000Kpcs / Month

1,500K 500K 1,600K 1,400K

1999 CQ1 2,022Kpcs / Month 65K 1,958K

2003 10,000Kpcs / Month

2000 April 2,150Kpcs / Month

550K 3K 1,147K 450K 2000 CQ3 3,500Kpcs / Month 1,000K 300K 1,200K 1,000K

１． HDD Spindle Motor Business - Current Prospect

3.5-inch Lowend, Desktop PC/STB 3.5-inch Highend, Desktop PC 2.5-inch Mobile 3.5-inch Highend, Enterprise/Host As of April 2000, our monthly production volume of HDD spindle motors stood at 2,150,000, but we expect this level to reach 3.5 million during the third quarter of 2000 and 5 million during the third quarter of 2001. The "3.5-inch highend, desktop" shown in Figures refers to spindle motors for 3.5-inch HDDs that are now said to have the largest storage capacity in the

• world. We expect to produce 10 million HDD spindle motors each month during 2003.

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Annual production quantity K=1,000pcs Excluding Minebea, Other Manufacturers total, referenced from Pixie Pinnacle Corporation

114,600K

20%

117,600K

13%

140,400K

14%

189,000K

21%

240,000K

25%

272,000K

30%

330,000K

36%

0K 50,000K 100,000K 150,000K 200,000K 250,000K 300,000K 350,000K 400,000K

Shipping Quantity [pcs]

1997 1998 1999 2000 2001 2002 2003

HDD Spindle Motor Forcast

Others Minebea

１．HDD Spindle Motor Business - Current Prospect

Our market share of HDD spindle motors is expected to rise from 21% in 2000 to 36% in 2003. We have calculated the market size by adding about 10% to Pixie Pinnacle Corporation's estimate.

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Floating inner ring Motor hub Outer ring with two raceways Balls + Cage

Preload

Shaft with integrated raceway

２． RO Bearing Motor – Performance and Advantage

Stracture of RO Bearing

An RO bearing is composed of one outer ring with two raceways, one shaft with one raceway, and one inner ring with one raceway.

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RO discrete

Resonance Range ( Max. ～ Min. ) at Different Rotational Speeds

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 RO Bearing Motor Discrete Bearing Motor Discrete Bearing Motor, 10μm- Misaligned Discrete Bearing Motor, 20μm- Misaligned

Resonance Range @20°C [Hz]

@4,500rpm @5,400rpm @7,200rpm

Thermal ( 20°C ～ 60°C ) Radial Runout Shift

0.00 0.10 0.20 0.30 RO Bearing Motor Discrete Bearing Motor Discrete Bearing Motor, 10μm- Misaligned Discrete Bearing Motor, 20μm- Misaligned Radial Runout [μm] Mean 3σ

Thermal ( 20°C ～ 60°C ) Resonance Shift 10.0Hz 6.1Hz

0.0 2.0 4.0 6.0 8.0 10.0 12.0 RO Bearing Motor Discrete Bearing Motor

Resonance Shift [Hz] RO Bearing Motor Discrete Bearing Motor

２． RO Bearing Motor – Performance and Advantage Graph A Graph C Graph B

The key features of RO bearing motors are that they are less affected by temperature variation and that they suffer no misalignment. The advantages of RO bearings over discrete bearings are evident as shown in Graphs A (Thermal Resonance Shift) and B (Resonance Range at different Rotational Speed), and Graph C (Thermal Radial Runout Shift).

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6 Resonance Range ( @25°C )

23.2Hz 11.8Hz

0.0 5.0 10.0 15.0 20.0 25.0 RO-Bearing Motor Discrete Bearing Motor Resonance Range [Hz]

NRRO, Axial, With Disk, OverAll 0.55μm 0.40μm 0.0 0.1 0.2 0.3 0.4 0.5 0.6

RO-Bearing Motor Discrete Bearing Motor

NRRO, Axial [μm]

2.5 inch Spindle Motor Performance ～RO Bearing stiffness results in smaller NRRO and narrower Resonance range. ～

２． RO Bearing Motor – Performance and Advantage

RO bearings have advantages in NRRO and resonance range. They have a high reputation as bearings for use in spindle motors for 2.5-inch, notebook type HDDs which require higher accuracy.

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Loosing of Preload Ball Bearing with Steel Balls: Same Ball and Ring Materials => Same Thermal Expansion Ball Bearing with Ceramic Balls: Different Ball and Ring Material => Different Thermal Expansion

No Preload Loosing Problem in Temperature Variation Preload Loosing Problem in Temperature Variation

Technical Problem of Ball Bearings with Ceramic Balls

２． RO Bearing Motor – Performance and Advantage

Generally speaking, in discrete ball bearings, when we use ceramic balls that have different thermal expansion rate from steel rings a technical problem of the preload loosing occurs.

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Room Temperature High Temperature Prevention of the Loosing Preload in RO Bearing with Ceramic Balls

２． RO Bearing Motor – Performance and Advantage

When assembled into a motor, the outer ring of RO Bearing is compressed as shown in the above figure. This assembling method prevents the problem of the preload loosing at high

• temperature. We have applied for a patent for this structure.

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Principle of Compensating the Preload

２． RO Bearing Motor – Performance and Advantage

In the case of RO bearing, pre-load is retained even when its outer ring is elongated due to a rise of temperature, since the compression of the outer ring is released to the longitudinal

• direction. The contact angle only changes slightly.

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Difficulty of Retaining the Preload in Discrete Ball Bearings with Ceramic Balls

Compression of Spacer

NO

２． RO Bearing Motor – Performance and Advantage

Compression of Outer Ring In the case of discrete ball bearings with Ceramic Balls, the same principle to prevent the loosing of preload is not applicable.

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2000 CQ3 3,500Kpcs / Month

Discrete Bearing

RO- Bearing 61%

2000 April 2,150Kpcs / Month

Discrete Bearing

RO- Bearing 45%

Projection of RO Bearing Motor Production

２． RO Bearing Motor – Performance and Advantage

All of our spindle motors for 2.5-inch and 3.5-inch, highend desktop HDDs use RO bearings. Production of RO bearing motors is expected to grow further in the future.

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Reality ・High Cost ・Questionable reliability

Burr/Contamination

Oil Leakage

Contradiction

Cost is a Key to the Success in FDB Business.

３． Fluid Dynamic Bearing – Minebea Strategy

Sales talk ・ Low Cost ・Good Performance NRRO/Noise/ Speed

The number of components used in fluid dynamic bearings are fewer than those used in other types of bearing. Thus, the price of fluid dynamic bearings should be lower by that count.

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FDB developed by Seagate

Capital expenditure： 2 Ball Bearings + 1 Shaft > 1 FDB Reliability: Excellent Design and know-how

(Burr Free, less Contamination and No Oil Leakage)

３． Fluid Dynamic Bearing – Minebea Strategy

(Greater than)

The fluid dynamic bearing developed by Seagate Technologies Inc. satisfies our requirements with regards to both cost and reliability.

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Capital expenditure for Additional HDD Spindle Motor Production Capacity

Existing capacity

• 4Mil. Units/Month

Additional Capacity

• 6Mil. Units/Month

at ¥7.5 Billion

• 10Mil. Units/Month

FDB Mass production starts within year 2000

３．Fluid Dynamic Bearing – Minebea Strategy

＋

We will start the mass production of fluid dynamic bearings by the end of 2000. We will invest 7.5 billion yen in Bang Pa-in, Thailand to build a HDD spindle motor plant with a monthly production capacity of 6 million units. After the completion of the new plant, our monthly production capacity of HDD spindle motor, including the existing production lines, will be 10 million units.

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Spindle Motor Performance Comparison by Bearing Types

（Note）RO : Ceramic Ball Type

３．Fluid Dynamic Bearing – Minebea Strategy

NRRO Life, High Speed Rotation

Acoustic Noise Load Carrying Capacity Torque Shock Torrelance Thermal Characteristics Cost Advantage Rotating Direction Ease of Assembly

RO △ △ ○ ◎ ○ ○ ○ ◎ Both ○ ○ ○ ○ ◎ ○ ○ ◎ ◎ Both ◎ ◎ ◎ ◎ △ ？ ？ ？ ？ Specific ？ Discrete

Non Minebea’s

FDB

The question mark placed on fluid dynamic bearings means that they will vary depending upon FDB's, design and manufacturing process. The above comparison clearly shows that RO bearings have certain advantages over discrete bearings.

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Spindle Motor Performance Comparison by Bearing Types

（Note）RO : Ceramic Ball Type

３．Fluid Dynamic Bearing – Minebea Strategy

NRRO Life, High Speed Rotation

Acoustic Noise Load Carrying Capacity Torque Shock Torrelance Thermal Characteristics Cost Advantage Rotating Direction Ease of Assembly

RO △ △ ○ ◎ ○ ○ ○ ◎ Both ○ ○ ○ ○ ◎ ○ ○ ◎ ◎ Both ◎ Discrete

Minebea’s

FDB

◎ ◎ ◎ △ ○ ○ ○ ◎ Specific ○

In the case of Minebea‘s fluid dynamic bearings, the question mark will turn to O or ◎. The fluid dynamic bearings have an NRRO and noise advantage over ball bearings. However, at highspeed rotation, the fluid dynamic bearings lose these advantages due to the disc dynamics and wind noises. Minebea's fluid dynamic bearings include fluid dynamic bearings designed for the highspeed rotation type HDDs and those designed for 2.5-inch HDDs. At present, however, we believe that the immediate area in which we can make the best use of the features of fluid dynamic bearings is the area of lowend HDDs, including HDDs for AV

• application. The best advantage of Minebea's fluid dynamic bearings is their low cost. With

this in mind, we believe that Minebea's fluid dynamic bearings best suit lowend HDDs.

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Ball Bearing Sales Results & Forecast

November 1999 126,417Kpcs P/O received February 2000 121,264

90,000K 100,000K 110,000K 120,000K 130,000K 140,000K

Mar-98 Jun-98 Sep-98 Dec-98 Mar-99 Jun-99 Sep-99 Dec-99 Mar-00 Jun-00 Sep-00

Quantity / Month [ pcs ]

Results Forecast

• 4. Fluid Dynamic Bearing – Minebea Strategy

Since fluid dynamic bearings have a weakness in load carrying capacity and the limitation of rotational direction, while having an NRRO and noise advantage over ball bearings, their applications will be limited. However, even if all bearings for HDD spindle motors are replaced by fluid dynamic bearings, our ball bearing businesses will not be overly affected.

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RRO, Radial, OverAll

0.09μm, Average 4.52μm, Average 0.0 1.0 2.0 3.0 4.0 5.0 6.0

RO-Bearing Discrete Bearing

RRO, Radial [μm] Rotating accuracy comparison between RO bearing and Discrete Bearing for Pivot Assy.

Eg.１：Precision Pivot Assy. Though we now have a strong demand of RO Bearing for HDD Spindle Motors, we will explore new applications.

NRRO, Radial, OverAll

0.07μm, Average 0.21μm, Average 0.00 0.05 0.10 0.15 0.20 0.25

RO-Bearing Discrete Bearing

NRRO, Radial [μm] ５. RO Bearing – Future Application

We consider high precision pivot assembly as a new application area for RO bearings. In the case of HDDs, higher accuracy is required not only for the HDD spindle motors that function to rotate the disks, but also for the pivot assemblies that function to control the position of heads.

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Pivot Assy Sales Results & Forecast

February 2000 8,335Kpcs October 1999 9,480Kpcs P/O received

4,000K 6,000K 8,000K 10,000K 12,000K

Mar-98 Jun-98 Sep-98 Dec-98 Mar-99 Jun-99 Sep-99 Dec-99 Mar-00 Jun-00 Sep-00

Quantity / Month [ pcs ]

Results Forecast

５. RO Bearing – Future Application

We expect that market demand for our pivot assemblies will increase further in the future.

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RO Bearing Fan Motor

• Ultra High Performance & High Reliability -

５. RO Bearing – Future Application

Impeller RO Bearing Yoke Casing Casing

We consider ultrahigh performance, highly reliable fan motors as the next application area for RO bearings. We can obtain the stable rotation of fan motors by using RO bearings. In addition, we can multiply the operating life by three times or more if ceramic balls are used. High performance, highly reliable fan motors are expected to be used in a wide variety of areas, including the aerospace, information and telecommunication industries.

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• Product Design
• Product Development
• Tool/Equipment Development
• Electrical/Software

Development.

• Production Engineering
• Quality Engineering
• Pilot Production
• Clean Technology
• Material Science
• Tribology
• Reliability
• Planning
• Product Design
• Product Development
• Tool/Equipment

Development

• Electrical/Software

Development

• Production Engineering
• Quality Engineering

Thailand

R & D Germany Japan

57 53 20 15

• Mass Production

６．Minebea Production Support and It’s Organization

Motor Engineer ：９２ R&D Engineer ：５３

At present, Minebea has 92 HDD spindle motor engineers and 53 R&D engineers.

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Planning Sample Production Design & Development Mass-Production

R&D

Japan Germany Thailand Singapore

S u p p

• r

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６．Minebea Production Support and It’s Organization

Thailand Germany Japan Japan Thailand Germany Japan

We are engaged in the design and development of HDD spindle motors in both Japan and

• Germany. We mass-produce HDD spindle motors in Thailand. Our R&D centers in various

parts of the world support these operations.

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１．Minebea HDD Spindle Motor expects Strong Demand and Steep Growth.

７．Summary

２．Minebea HDD Spindle Motor continues to use RO Bearing because of its Superior Performance. ３．Minebea FDB has Advantages in both Cost and Reliability. ４．FDB does not Affect has Minebea’s Current Ball Bearing Business. ５．RO Bearing will be used not only for HDD Spindle Motors but also for Other High Value Added Products. ６．Globalized R&D Production set up will enhance Minebea’s Further Growth.