Minebea Co., Ltd. [ ROF-Type HDD Spindle Motors ]

Annual sales of our spindle motors for 3.5-inch HDDs are currently approximately ¥40.0 billion.
Our newly developed ROF-type FDB unit will enable us to significantly lower costs for these motors.

HDD Spindle Motors
Improving the profitability of our Electronic Devices and Components business segment hinges on our ability to raise the profitability of our HDD spindle motors business. This, in turn, depends on lowering costs for FDB spindle motors for 3.5-inch HDDs and entering the rapidly expanding market for FDB spindle motors for 2.5-inch or smaller HDDs. Our new ROF-type FDB spindle motor was developed primarily for use in 2.5-inch or larger HDDs, while our HMF-type FDB spindle motor was developed for use in 2.5-inch or smaller HDDs.

Market for Spindle Motors for 3.5-inch HDDs

Despite intense pressure on the profitability of this business, owing to the steady erosion of motor prices, we continue to command a global market share of approximately 30%. Accordingly, we are well positioned to strengthen our profit performance if we can achieve necessary, significant cost reductions.

With the aim of significantly lowering costs for FDB spindle motors, we developed the ROF-type FDB unit:

ROF-Type FDB Unit (Patents Pending)

Basic Development Concept

Unmatched
suitability to
mass production

Unrivaled
cost
competitiveness

Outstanding
performance

The basic development concept for our ROF-type FDB unit was to create an FDB that was unmatched in terms of suitability to mass production and offered unrivaled cost competitiveness and outstanding performance.

Features

ROF-type FDB units are manufactured using the same manufacturing technologies, production lines and production methods as our ball bearings, monthly global output of which is currently over 170 million pieces. As with ball bearings, steel is put through quenching and grinding processes to form the bearing, the heart of the FDB unit.

Same manufacturing
technologies

Same production
lines

Same production
methods

We began sample shipments of spindle motors with ROF-type FDB units, primarily for 3.5-inch HDDs, in June 2004, and intend to commence mass production in late 2004.

Production Cost for Miniature and Small-Sized Ball Bearings

Comparison of ROF-Type and Conventional FDB Units

Because ROF-type FDB units are produced on the same lines as ball bearings, requirements in terms of personnel, manufacturing space and processing time are significantly reduced. As a consequence, production cost is approximately one-half of that of conventional FDB units, giving Minebea a considerable advantage in terms of cost competitiveness.

Structure of ROF-Type FDB Unit

The ROF-type FDB unit comprises four parts. In conventional FDB units, the bearing and the casing are integrated in a single component, called the sleeve. In the ROF-type FDB unit, however, the bearing and the casing are independent. This enables us to manufacture the bearing - the costliest part of the FDB unit - using the same manufacturing technologies, production lines and production methods as we use for ball bearings. The two remaining parts of the ROF-type FDB unit - the shaft assembly and the counter plate - are the same as those used for our conventional FDB units.