Voice coil motor with shielded coil portion

#The present invention relates generally to electromagnetically actuated apparatus. More particularly, the present invention relates to an improved voice coil motor.

#Voice coil motors are useful for providing controllable motion. One practical application of voice coil motors can be found in data storage devices where a voice coil motor is used for controllably positioning read/write heads with respect to storage media.

#While various voice coil motors have been proposed in the past, there remains a need to provide a voice coil motor with improved torque at reduced cost. Other considerations that may determine the commercial utility of a voice coil motor include ease of manufacture and assembly.

#FIG. 1 is a perspective view of a disc drive.

#FIG. 2 is a perspective view of a voice coil motor according to one embodiment of the present invention.

#FIG. 3 is a schematic diagram of the voice coil motor of FIG. 2.

#The disc drive 10 illustrated in FIG. 1 is one example of a data storage device in which a voice coil motor 12 of the present invention is applied. Provided within a protective housing 14, which may comprise a base 16 and a complementary cover 18, are storage media and apparatus for storing and retrieving data from the storage media. In this example, storage media is provided in the form of one or more discs 20. Each disc 20 is secured to a spindle motor 22, forming a disc stack assembly that is rotatably mounted to the base 16. Read/write heads 24 are supported by an actuator 26 so that they can be brought into proximity to a corresponding disc surface at various desired radial locations during drive operations. The actuator 26 may include a body 28 pivotably mounted to the base 16 and one or more actuator arms 30 extending from the body 28. Each actuator arm 30 is joined to one or more suspensions 32 from which the read/write heads 24 are supported. Extending substantially diametrically from the actuator arms 30 is a movable part of a voice coil motor. The remaining part of the voice coil motor is mounted to the base 16 or cover 18. Circuitry required for drive operations is generally located on a printed circuit board assembly 34 attached to an underside of the base. Within the protective housing 14, flex circuits 36 are used to accommodate moving components such as the actuator 26.

#Following the trend of increasingly smaller consumer electronic devices, there is a desire to reduce the size of data storage devices such as disc drives. As can be seen from the brief description provided above of an exemplary disc drive, there is limited space within the protective housing for the various components. In such applications, a voice coil motor fashioned according to one embodiment of the present invention can be particularly useful as it requires less space while providing comparable or improved torque in comparison with conventional voice coil motors.

#A voice coil motor 12 according to one embodiment of the present invention is shown in FIG. 2. A support 40 extends from the body 28 of the actuator in a direction substantially diametric to the one or more actuator arms 30. The voice coil 42 is fixed to the support 40 such that it presents a first coil portion 44 and an opposing second coil portion 46 that is each substantially perpendicular to the axis of rotation 48 of the actuator. The first coil portion 44 and the second coil portion 46 are joined by a third coil portion 50 and an opposing fourth coil portion 52, each of which is substantially parallel to the axis of rotation 48 of the actuator.