Magnetic head separator fin material to prevent particulate contamination on slider

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser. No. 61/951,997 filed on Mar. 12, 2014, which is expressly incorporated by reference herein in its entirety.

BACKGROUND

A hard disk drive includes a rotatable storage disk, with magnetic reader heads and writer heads that can be placed in park when the device is not actively reading or writing. A head assembly of reader and writer heads is positioned on a slider, which is a base substrate structure for the head assembly. A ramp is a structure designed to guide and seat a suspension arm for the head assembly when parking. An armature holding the head assembly rotates to an end position toward the ramp, allowing a tip assembly to engage with the ramp, with the head assembly kept at a clearance gap from the ramp. While in park, an opposing slider and head assembly, used for reading and writing on the opposite side of the storage disk, resides below the first slider and head assembly. In order to protect the opposing sliders from clashing with each other upon a shock event (e.g., if the device is dropped or bumped during or after assembly), a separator fin extends outward from the ramp into the space between the parked sliders. However, while the fin protects the top slider from contacting and damaging the bottom slider, small shock events may bring the top and/or the bottom slider into contact with the fin. This contact may leave debris deposits, such as particulate residue, from the fin material onto the slider, and may cause smearing on the slider. This residue and smearing may lead to contamination-related failures of the magnetic reader and writer heads.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the present invention will now be presented in the detailed description by way of example, and not by way of limitation, with reference to the accompanying drawings, wherein:

FIG. 1 shows a diagram of an exemplary hard disk drive;

FIG. 2 shows a diagram of an exemplary ramp assembly with a fin structure composed of a different material;

FIG. 3 shows a top view detail of an exemplary ramp assembly with a fin structure in a relative position with a parked suspension arm of a head gimbal assembly; and

FIG. 4 shows a side view detail of an exemplary ramp assembly and fin arranged between top and bottom sliders in a parked position on the ramp.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various exemplary embodiments and is not intended to represent the only embodiments that may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that the embodiments may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the embodiments. Acronyms and other descriptive terminology may be used merely for convenience and clarity and are not intended to limit the scope of the embodiments.

The various exemplary embodiments illustrated in the drawings may not be drawn to scale. Rather, the dimensions of the various features may be expanded or reduced for clarity. In addition, some of the drawings may be simplified for clarity. Thus, the drawings may not depict all of the components of a given apparatus.

Various embodiments will be described herein with reference to drawings that are schematic illustrations of idealized configurations. As such, variations from the shapes of the illustrations as a result of manufacturing techniques and/or tolerances, for example, are to be expected. Thus, the various embodiments presented throughout this disclosure should not be construed as limited to the particular shapes of elements illustrated and described herein but are to include deviations in shapes that result, for example, from manufacturing. By way of example, an element illustrated or described as having rounded or curved features at its edges may instead have straight edges. Thus, the elements illustrated in the drawings are schematic in nature and their shapes are not intended to illustrate the precise shape of an element and are not intended to limit the scope of the described embodiments.

The word “exemplary” is used herein to mean serving as an example, instance, or illustration. Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. Likewise, the term “embodiment” of an apparatus or method does not require that all embodiments include the described components, structure, features, functionality, processes, advantages, benefits, or modes of operation.

As used herein, the term “about” followed by a numeric value means within engineering tolerance of the provided value.

In the following detailed description, various aspects of the present invention will be presented in the context of a ramp assembly used to park a magnetic head assembly when idle in a disk-based storage device, such as a hard disk drive (HDD) or a solid state hybrid drive (SSHD).

An aspect of a ramp apparatus includes a ramp body constructed of a first material, the ramp being configured to guide and hold a magnetic head assembly in place when parked, and a fin being formed with a second material different than the first material. The fin is arranged with the ramp to protect a top magnetic head assembly from contacting a bottom magnetic head assembly during a shock event when parked on the ramp.

FIG. 1 shows a hard disk drive 111 including a disk drive base 114, at least one rotatable storage disk 113 (such as a magnetic disk, magneto-optical disk, or optical disk), and a spindle motor 116 attached to the base 114 for rotating the disk 113. The spindle motor 116 typically includes a rotating hub on which one or more disks 113 may be mounted and clamped, a magnet attached to the hub, and a stator. At least one suspension arm 108 supports at least one head gimbal assembly (HGA) 112 that holds a slider with a magnetic head assembly of writer and reader heads. A ramp assembly 100 is affixed to the base 114, and provides a surface for tip of the suspension arm 108 to rest when the HGA 112 is parked (i.e., when the writing and reading heads are idle). During a recording operation of the disk drive 111, the suspension arm 108 rotates at the pivot 117, disengaging from the ramp assembly 100, and moves the position of the HGA 112 to a desired information track on the rotating disk 113. A typical hard disk drive 111 uses double sided disks 113 to allow read/write operation on both sides of the disk 113. As such, a second, opposing HGA 112 supported by a second suspension arm 108 (both are not visible in FIG. 1) may be arranged on the underside of the disk 113. The bottom of the ramp 100 may be configured with a surface that accepts the tip of the second suspension arm 108 when the second HGA 112 is parked.

FIG. 2 shows a diagram of an exemplary ramp assembly 100, having a ramp body 105 with a ramp 102 and a fastening slot 114. The ramp assembly 100 also includes a fin 104, which is a means for protecting opposing sliders from contacting each other when the sliders and magnetic head assemblies are parked on the ramp. The fin 104 is a protruding structure that extends from the ramp body 105 in a suspended position between the opposing sliders when parked. As shown in FIG. 2, the fin 104 may be configured in a rectangular shape and a thin vertical profile which conforms to the space between the sliders and the boundaries of the suspended slider position. The relative position of the fin 104 to the sliders will be explained in further detail below with respect to FIG. 3 and FIG. 4.

The material composition of the ramp body 105 may be a durable and resilient plastic material having a hardness suitable for a rigid base to support one or more HGAs 112 and respective suspension arms 108. Also, the ramp body 105 material composition should have a coefficient of friction low enough to permit free and unhindered sliding of the tip of suspension arm 108 on and off of the ramp 102 for entering and leaving the parked position. For example, the material composition of the ramp body 105 may be polyoxymethylene (POM). The material composition of the ramp body 105 may be either POM alone, or a compound that is primarily POM.

The material composition of the fin 104 may be a plastic material selected according to predetermined thresholds hardness, durability, and low material transfer (e.g., residue smearing) on contact. Additional criteria for the material may include a hardness value below a maximum hardness threshold to avoid chipping the slider during a shock event or generating debris from reinforcing fillers or fibers or the main plastic material. For example, the material formulations for the fin 104 may exhibit hardness in a range of about 95-130 (Rockwell M), and a tensile modulus higher than about 2.5 GPa with a limit at about 10 GPa.

In one embodiment, the material composition of the ramp body is different than the material composition of the fin 104. For example, the ramp body 105 may be constructed of POM, and the fin 104 may be constructed of a material that is substantially free of POM, such as polyetherimide (PEI). In this example, the ramp assembly 100 may be fabricated in a two shot mold injection process for a POM based ramp body 105 and a PEI based fin 104. Alternative materials for the fin 104 material composition may include any one of the following: polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyethersulfone (PES), polyimide, polyamide-imide.

The ramp body 105 and fin 104 may be affixed to each other in any one of various techniques, including but not limited to fusion bonding, solvent bonding, ultrasonic boding, a mechanical fastener, or fastening elements formed into each part (e.g., threaded elements, detents, etc.).

FIG. 3 shows a top view of the ramp assembly 100 with the suspension arm 108 parked on the ramp 102. The slider (not visible) is affixed to the head gimbal assembly which is supported by the suspension arm 108. The slider is suspended just above the surface of the fin 104 with a small clearance. The suspension arm 108 slides to the left to leave the parked position, and slides back over the ramp 102 to return to the parked position as shown. As shown in FIG. 3, the fin 104 may be configured with a shape that conforms to the adjacent ramp 102 for providing protection between the opposing sliders along the length of the ramp 102 as the suspension 108 approaches and departs the ramp 102. The length of the fin 104 may be approximately equivalent to the length of the ramp 102, with a minimum length corresponding to the boundary of the suspended sliders when parked.

FIG. 4 shows a side view of the same ramp assembly 100 as shown in FIG. 3 with the suspension arm 108 parked on the ramp 102. In this view as shown in FIG. 4, both the top suspension arm 108A and bottom suspension arm 108B are visible. Also shown is the parked tip 110 of the suspension arm 108A, which rests on the surface of ramp 102. The fin 104 is arranged between the top slider 112A and the bottom slider 112B, which prevents two sliders from contacting each other during a shock event while in the parked position. The fin 104 may be configured with a width (i.e., the dimension extending out perpendicular and away from the ramp 102) that corresponds with the boundary of the suspended sliders 112A and 112B, which are shown suspended from suspension arm 108. The fin 104 may also be configured with a maximum thickness that provides clearance for the sliders 112A and 112B to pass above and below the fin 104 when being parked by the suspension arms 108A and 108B without contacting the fin 104, and a minimum thickness that provides adequate sturdiness to protect the sliders upon contact with the fin 104 during a shock event.

With the fin 104 positioned as shown in FIG. 4, the top slider 112A or the bottom slider 112B, or both, may contact the fin 104 in response to a vibration or shock event to the hard disk drive assembly 111 (e.g., external forces from the environment, such as a bump to the hard disk drive 111 during manufacturing, assembly, or operation), thus protecting against direct slider to slider contact. Constructing the fin 104 with a non-POM material, the top slider 112A and the bottom slider 112B may remain free from deposits, such as particulate residue, from the fin 104 material onto the sliders 112A, 112B, or substantially free of such deposits, for an extended service life of the read and write heads on sliders 112A and 112B.

The various aspects of this disclosure are provided to enable one of ordinary skill in the art to practice the present invention. Various modifications to exemplary embodiments presented throughout this disclosure will be readily apparent to those skilled in the art, and the concepts disclosed herein may be extended to other devices. Thus, the claims are not intended to be limited to the various aspects of this disclosure, but are to be accorded the full scope consistent with the language of the claims. All structural and functional equivalents to the various components of the exemplary embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112(f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”