Rotary drive for a data carrier

Abstract

A data medium is driven by a brushless direct current more, and possesses control signals en a track which can be picked up by a sensing device and supplied to a switch arrangement for activation of the motor winding. The control signals on the track characterize at least those angular positions of the rotor with respect to the stator in which commutation is to be initiated.

Description

BACKGROUND OF THE INVENTIONThe invention concerns rotation-impairing drive unit for rotating a data carrier having a brushless d.c. motor with a permanent-magnet rotor, and a stator having a winding, the winding being formed by one or plural winding coils, a circuit arrangement for controlling the energization of the winding to generate a magnetic field effecting rotary motion of the rotor, and also a reading arrangement for reading signals recorded on the data carrier.For driving daft carriers such as computer data-storage planers use is generally made of a brushless d.c. motor, with a data-carrier-receiving hub preferably being secured directly a the motor's shaft, so that the data carrier be directly driven. In order to assure a reliable, error-free reading of the data signals despite high daft recording density, it is necessary to drive the data carrier at a high speed that is uniform; for this purpose, as exact as possible a switchover (commutation of the current fed to the d.c...

AI Technical Summary

Benefits of technology

The advantage of the invention resides in particular in the fact that, by using components that are anyway present in a data-storage unit of the type here in question, one can entirely eliminate the sensor structure that in prior art was conventionally provided internal to the motor, and can furthermore eliminate the associated circuitry and circuit board. As there no longer needed components were arranged in the motor housing at an axial end thereof, it becomes possible to shorten the axial length of the motor correspondingly. At the same time, one eliminates problems associated with the need to connect inside the motor housing, a perhaps rather high number of coil ends to a circuit. Further, there no longer arises the particularly critical problem of the heating up of electronic components within the interior of the motor housing, which is closed and heats up as a result of the heating-up of the winding.

resides in particular in the fact that, by using components that are anyway present in a data-storage unit of the type here in question, one can entirely eliminate the sensor structure that in prior art was conventionally provided internal to the motor, and can furthermore eliminate the associated circuitry and circuit board. As there no longer needed components were arranged in the motor housing at an axial end thereof, it becomes possible to shorten the axial length of the motor correspondingly. At the same time, one eliminates problems associated with the need to connect inside the motor housing, a perhaps rather high number of coil ends to a circuit. Further, there no longer arises the particularly critical problem of the heating up of electronic components within the interior of the motor housing, which is closed and heats up as a result of the heating-up of the winding.

The to the relatively large data carrier diameter and high resolution or the recorded signals, very exact angular positioning of the commutation-control signals can be realized. Also, and without added cost, plural signals can be provided for each time of switchover in the supply of current to the winding, so that e.g. speed-regulating units effective during small amounts of angular motion can be provided, such that immediate corrective adjustment of the supply of energizing current to the winding become possible. Such speed-regulating units, when used in conjunction with sets of desired-speed data, make possible the implementation of speed profiles, for example acceleration and deceleration profiles.

Problems solved by technology

Further, there no longer arises the particularly critical problem of the heating up of electronic components within the interior of the motor housing, which is closed and heats up as a result of the heating-up of the winding.

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