Patent Application
20080239574
1. Technical Field
The present invention relates in general to disk drives and, in particular, to an improved system and apparatus for providing a streamlined contour and reduction in axial flow at the suspension-to-flexure attachment interface in a disk drive.
2. Description of the Related Art
Data access and storage systems generally comprise one or more storage devices that store data on magnetic or optical storage media. For example, a magnetic storage device is known as a direct access storage device (DASD) or a hard disk drive (HDD) and includes one or more disks and a disk controller to manage local operations concerning the disks. The hard disks themselves are usually made of aluminum alloy or a mixture of glass and ceramic, and are covered with a magnetic coating. Typically, one to five disks are stacked vertically on a common spindle that is turned by a disk drive motor at several thousand revolutions per minute (rpm).
A typical HDD uses an actuator assembly to move magnetic read/write heads to the desired location on the rotating disk so as to write information to or read data from that location. Within most HDDs, the magnetic read/write head is mounted on a slider. A slider generally serves to mechanically support the head and any electrical connections between the head and the rest of the disk drive system. The slider is aerodynamically shaped to glide over moving air in order to maintain a uniform distance from the surface of the rotating disk, thereby preventing the head from undesirably-contacting the disk.
A slider is typically formed with an aerodynamic pattern of protrusions on its air bearing surface (ABS) that enables the slider to fly at a constant height close to the disk during operation of the disk drive. A slider is associated with each side of each disk and flies just over the disk's surface. Each slider is mounted on a suspension to form a head gimbal assembly (HGA). The HGA is then attached to a semi-rigid actuator arm that supports the entire head flying unit. Several semi-rigid arms may be combined to form a single movable unit having either a linear bearing or a rotary pivotal bearing system.
The head and arm assembly is linearly or pivotally moved utilizing a magnet/coil structure that is often called a voice coil motor (VCM). The stator of a VCM is mounted to a base plate or casting on which the spindle is also mounted. The base casting with its spindle, actuator VCM, and internal filtration system is then enclosed with a cover and seal assembly to ensure that no contaminants can enter and adversely affect the reliability of the slider flying over the disk. When current is fed to the motor, the VCM develops force or torque that is substantially proportional to the applied current. The arm acceleration is therefore substantially proportional to the magnitude of the current. As the read/write head approaches a desired track, a reverse polarity signal is applied to the actuator, causing the signal to act as a brake, and ideally causing the read/write head to stop and settle directly over the desired track.
In the prior art, airflow-induced vibration of the rotary actuator 11 (see, e.g.,
Embodiments of a system and apparatus for overcoming the adverse effect of flow-induced vibration of the rotary actuator are disclosed. An airflow deflector or diverter may be formed as a separate component or as an integral portion of the flex stiffener or the actuator itself. The invention streamlines the actuator to the incoming airflow and helps reduce the torque disturbance to the actuator as it reduces the sail or parachute effect. This helps reduce power consumption due to a lower drag from the actuator assembly. The contour of the flow deflector is designed to conform closely to the curvature of the disk boundaries when the actuator is rotated to the ID position on the disk. This design serves as a shroud around the disk stack which further helps to reduce power by preserving flow momentum.
In addition, axial or cross airflow impinging on the ILS tail pads is greatly reduced and thereby reduces ILS tail flutter and any vibration from being transmitted to the arm. In one embodiment, the invention is an integral part of the flex stiffener and also helps increase heat conduction away from the stiffener while improving heat dissipation from forced convection. The invention further reduces the likelihood of damage (e.g., bending) to the flex stiffener during handling since it now abuts against the flow deflector which provides a stable support surface.
In one embodiment, the geometry of the disk and actuator provide a concave shape to the modified streamlined contour of the diverter. The shape may be bounded by the original contour of the actuator and extend as a surface from the tip of the flex attachment or stiffener (e.g., tangentially) to the original contour. Various other embodiments may be adjusted for the overall actuator and disk geometries as well as the required functionality, such as TMR requirements, etc.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings.
So that the manner in which the features and advantages of the present invention, which will become apparent, are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings which form a part of this specification. It is to be noted, however, that the drawings illustrate only some embodiments of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
Referring to
In the embodiment shown, each arm 125 has extending from it at least one cantilevered load beam and suspension 127. A magnetic read/write transducer or head is mounted on a slider 129 and secured to a flexure that is flexibly mounted to each suspension 127. The read/write heads magnetically read data from and/or magnetically write data to disk 115. The level of integration called the head gimbal assembly is head and the slider 129, which are mounted on suspension 127. The slider 129 is usually bonded to the end of suspension 127. The head may be pre-loaded against the surface of disk 115 by suspension 127.
Suspensions 127 have a spring-like quality which biases or urges the air bearing surface of the slider 129 toward the disk 115 to enable the creation of the air bearing film between the slider 129 and disk surface. A voice coil 133 housed within a conventional voice coil motor magnet assembly 134 (top pole not shown) is also mounted to arms 125 opposite the head gimbal assemblies. Movement of the actuator 121 (indicated by arrow 135) by controller 119 moves the head gimbal assemblies radially across tracks on the disk 115 until the heads settle on their respective target tracks. The head gimbal assemblies operate in a conventional manner and always move in unison with one another, unless drive 111 uses multiple independent actuators (not shown) wherein the arms can move independently of one another.
Referring now to
As best shown in
Referring now to
The diverter 161 may be configured in many different ways. For example, the diverter 161 may be integrally formed with a barrel 163 (
In another example, when the disk drive comprises embodiments having two or more disks 115, the diverter 161 may be formed from a lightweight plastic material having a plurality of fins 165 (
As best shown in
In some embodiments, the diverter may include a concave surface 173 (
While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.
