Patent Application
20050057860
The present invention relates generally to actuator assemblies for use in data storage devices. More particularly, the present invention relates to the manufacture of such assemblies.
Consumer demand for increasingly smaller and lighter portable electronic devices with improved and more reliable data storage capabilities is driving the push for miniaturization of data storage devices. In designing smaller and more robust data storage devices, engineers are faced with many challenges, one of which is the difficulty of assembling movable components. Conventional fasteners or assemblies may add to the thickness or width of the assembly, and thus be a hindrance to further overall size reduction of the data storage device.
Conventional fasteners may be inadequate in another aspect. For example, when the size of the actuator assembly is reduced beyond a certain point, there may be insufficient frictional forces or insufficient area for the fasteners to effect a secure attachment. Therefore, with the miniaturization of data storage devices, there is a need to explore alternative methods of assembly.
At the same time, any alternative method of assembly should preferably be amenable to automation so that the final product, be it a data storage device or other consumer electronic device, can be made available to the public at affordable prices. Innovative solutions to such problems are required.
In addition to providing a solution that overcomes these and other problems, the present invention also offers further advantages over conventional assemblies.
The present invention relates to the assembly of actuator assemblies for use in data storage devices such as disc drives.
In accordance with embodiments of the invention, rotatable portions of an actuator assembly are metallurgically bonded together, for example by using lasers to form at least one spot-weld. The rotatable portions may include an actuator arm, a voice coil support, and the rotatable part of a pivot mechanism. Embodiments of the present invention may further provide for contact between the actuator beam and the rotatable part of the pivot mechanism. Preferably, contact is provided between at least a part of the actuator beam and at least one transverse extension from the rotatable part of the pivot mechanism.
Some embodiments involve welding an actuator beam to a rotatable part of the pivot mechanism, where the actuator beam is a monolithic structure having the actuator arm and the voice coil support. During assembly, components of the actuator assembly are preferably introduced to the place of assembly from generally the same direction as the laser.
These and various other features as well as advantages which characterize the present invention will be apparent upon reading of the following detailed description and review of the associated drawings.
Rotatably mounted to the base deck 102 is a disc stack assembly 110 made up of a disc 112 that is secured to a spindle motor by a disc clamp 114. The disc stack assembly 110 may be located in a cavity formed by the base deck 102 so that the disc stack assembly is at least partially surrounded by a shroud 116 extending transversely alongside the edge of the disc 112. When the disc stack assembly 110 rotates, air or fluid near the disc stack assembly is dragged into motion along with the rotating disc 112. A filter 118 may be positioned adjacent the disc stack assembly 110 to trap contaminants in the moving air or fluid, thereby helping to maintain a clean environment within the housing 101.
At least one of the major surfaces of the disc 112 is formatted for storing data. Data is written to and read from one or more tracks on a disc surface by read/write heads 120. The read/write heads 120 may be part of a head gimbal assembly 122 that is suspended from one end of a suspension 124, which is in turn attached to a pivotably mounted actuator arm 204. In addition to other functions, the actuator arm 204 serves as a framework for supporting wiring 126 (which may be in the form of a printed circuit cable) that runs from the head gimbal assembly 122 to a connector or bracket 128, from where it communicates with the printed circuit board assembly. A pre-amplifier 119 or other integrated-circuit chips may be located on the actuator assembly 126 to provide improved signal transmission.
In the present context, an actuator assembly 200 refers to an assembly that includes an actuator arm 204, a rotator 310, and a movable part 206 of a voice coil motor 130 that sets the actuator arm 204 in motion. The rotator 310 is a rotatable part of a pivot mechanism 310 for enabling rotational movement of the actuator arm 204. The movable part 206 of the voice coil motor 130 may be a voice coil support 206 to which a voice coil 136 is attached. The voice coil motor 130 further includes a permanent magnet 132 and a configuration of one or more poles 134 designed to close the magnetic flux from the magnet 132. By controlling the current to the voice coil 136 of the voice coil motor 130, the actuator arm 204 can be used to position the read/write heads 120 at a desired track when data is being read from or written to the track, or to move the read/write heads 120 to a new track location.
The actuator assembly 200 may be limited in its range of movement by suitable placement of limit stops or latches 138.
Turning to
One part of the actuator beam 202 that extends away from the aperture 208 serves as an actuator arm 204. The distal end of the actuator arm 204 provides for attachment to a suspension 124 that can support a head gimbal assembly 122 (
The pivot mechanism 300 can be one in which the rotator 310 is in engagement with a stationary portion 318 via a set of bearings 316 (
The rotator 310 of the pivot mechanism 300 includes a sleeve 312. The sleeve 312 is generally oriented along the axial direction 210. The sleeve 312 may be in the form of a hollow cylinder coupled on the inside to the bearings 316. A flange 314 extends radially outward from one edge of the sleeve 312, to provide at least one abutment surface 316 that is transverse to the axial direction 210. The abutment surface 316 is configured for abutment with at least part of the actuator beam 202. The abutment surface 316 may extend continuously along the circumference of the sleeve 312. Alternatively, the flange 314 may not be continuous throughout the circumference of the sleeve 312.
During the assembly process, the rotator 310 of the pivot mechanism 300 is assembled to the actuator beam 202 by fitting the sleeve 312 through the aperture 208 until the actuator beam 202 abuts the abutment surface 316 of the flange 314. As illustrated in
It is contemplated that the laser 400 may alternatively be directed from a direction that is at an angle to the axial direction 210, or it can be directed from a direction opposite to that shown in
It can be seen from the description above that, not only does the resultant actuator assembly 200 require fewer steps to assemble, fewer components will actually be required. Manufacture of the actuator assembly 200 is also simpler than conventional processes because no additional clamping or fastening processes are required. Overall, this can lead to improved manufacturing efficiencies and lower costs.
Furthermore, embodiments of the present invention are particularly suited for making miniature actuator assemblies where the amount of friction between very small interface areas may be insufficient for effecting a secure joint using other methods.
It is proposed that two spaced-apart laser welds 404, 404′ are formed, although the number of laser welds may be varied. By varying the size of the welds and the number of welds, the integrity of the assembly can be controlled. Material choice for the actuator beam 202 and the rotator 310 is not constrained by the method of assembly because laser welding can be used to effectively join together both similar and dissimilar materials.
It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
