1. Technical Field
The present invention relates in general to an improved suspension for a disk drive and, in particular, to an improved system, method, and apparatus for improving the performance of a four-piece suspension using a separate, extended hinge plate.
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). Hard disk drives have several different typical standard sizes or formats, including server, desktop, mobile (2.5 and 1.8 inches) and microdrive.
A typical HDD also 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, such as an integrated lead suspension (ILS), 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.
A typical four-piece ILS 11 is shown in
Referring now to
The change in elevation 15 is an undesirable bend in the structure of the flexure 13 that is required to go from a relative height of the load beam 3 to that of the hinge plate 2 on the mount plate 4. Such a bend puts a mechanical moment in the flexure 13, which can twist the HGA at the hinge springs 2A. This twist can increase the off-track motion of the slider under excitation, such as windage or any other external vibration in the file. It can be detrimental to the performance of the device.
One embodiment of a system, method, and apparatus for improving the performance of a four-piece suspension having a separate, extended hinge plate is disclosed. The present invention comprises an ILS flexure that is centrally-routed through the hinge area of the suspension and, in one version, is completely symmetrical. This design eliminates many of previously described problems associated with the prior art, including much of the unwanted off-track motion of the slider for bending modes. By extending the hinge plate from the base of the load beam to the base of the flexure legs, any height mismatch for the flexure is completely eliminated. The ILS flexure, hinge plate, and load beam may be welded together to provide a stiff structure for high torsional frequencies. Flexure torsional mode frequency is further increased by welding the flexure to the hinge plate and load beam at two locations closer to the dimple formed at the distal end of the suspension.
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. For example, other types of suspensions (e.g., wireless suspensions, CIS, etc.) that employ a four-piece construction also benefit from the present invention.
So that the manner in which the features and advantages of the invention, as well as others 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 embodiment thereof which is illustrated in the appended drawings, which drawings form a part of this specification. It is to be noted, however, that the drawings illustrate only an embodiment 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 now to
In the embodiment shown, each arm 125 has extending from it at least one of the suspensions 127. A magnetic read/write transducer or head is mounted on a slider 129 and secured to the 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 is typically pico size (approximately 1250×1000×300 microns) and formed from ceramic or intermetallic materials. The head also may be femto size (approximately 850×700×230 microns), Pemto size (approximately 1250×700×230 microns), or even smaller in size. The head is pre-loaded against the surface of disk 115 (e.g., in the range two to ten grams) by suspension 127.
The hinge of the suspension 127 has a spring-like quality which biases or urges the air bearing surface of the slider 129 against 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
The mount plate 151 is mounted to the arm 125 and extends in the longitudinal direction to define a first plane. The hinge plate 153 is mounted to the mount plate 151 and also extends in the longitudinal direction. As shown in
The flexure 155 is mounted to the load beam 157 and extends in the longitudinal direction. The read/write transducer 129 is mounted to the flexure 155 for reading data from and writing data to the magnetic media 115. The flexure defines and extends in a configuration that is parallel to the first and second planes. Thus, the flexure 155 may lie in a single plane (e.g., from flexure area 155A to 155B in
However, flexure 155 has no distortions that form mechanical moments therein. The plane defined by the flexure 155 extends from the mount plate 151 to the read/write transducer 129 to reduce undesirable off-track motion of the read/write transducer 129 relative to media tracks on the magnetic media 105. Furthermore, the flexure 155 may extend symmetrically down a lateral center of the hinge plate 153 and the load beam 157 to the read/write transducer 129.
The present invention has several advantages, including the ability to eliminate many of the problems associated with the prior art, such as the unwanted off-track motion of the slider for bending modes. Height mismatch for the flexure is eliminated by extending the hinge plate from the base of the load beam to the base of the flexure legs. The welded ILS flexure, hinge plate, and load beam provide a stiff structure for high torsional frequencies.
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. For example, other types of suspensions (e.g., wireless suspensions, CIS, etc.) that employ a four-piece construction also benefit from the present invention.