Browse Prior Art Database

Linear Actuator

IP.com Disclosure Number: IPCOM000051859D
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Bauck, RC: AUTHOR [+2]

Abstract

A low-cost star-shaped linear actuator for DASD (direct-access storage device) applications includes a plurality of printed circuit coils and magnetic gaps where the coil boards also provide a symmetrical rigid moving mass for improved dynamic performance. The plurality of coils provides a variety of connection combinations to tailor overall coil impedance and power requirements. The plurality of magnetic gaps tend to average the flux-fringing effects for improved force constant linearity.

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Linear Actuator

A low-cost star-shaped linear actuator for DASD (direct-access storage device) applications includes a plurality of printed circuit coils and magnetic gaps where the coil boards also provide a symmetrical rigid moving mass for improved dynamic performance. The plurality of coils provides a variety of connection combinations to tailor overall coil impedance and power requirements. The plurality of magnetic gaps tend to average the flux-fringing effects for improved force constant linearity.

As shown in Fig. 1, a low-cost, flexibly designable, linear actuator has a star- shaped carriage movably mounted on a mounting ring or shaft. A plurality, such as four, of printed circuit boards extend radially outwardly from the center of the carriage to form a symmetrical structure. Each printed circuit board carries two planar coils. Four arcuate permanent magnets, which are circumferentially magnetized, constitute the permanent magnet field of the actuator. Four complementary low carbon steel flux return segments are symmetrically disposed to the permanent magnets. The flux returns may also be permanent magnets of appropriate magnetic polarity if a longer magnetic path is desired. The magnets and return elements are suitably secured to the mounting ring. The polarity of the permanent magnets is appropriately chosen with the coil design to provide additive forces for efficiently moving the carriage. The electrical connections to the planar coils are achieved using usual co...