Patent Application
20050253342
The claimed invention relates generally to the field of housing structures and more particularly, but not by way of limitation, to an apparatus and method for forming a housing seal.
Disc drives are digital data storage devices which store and retrieve large amounts of user data in a fast and efficient manner. The data are magnetically recorded on the surfaces of one or more data storage discs (media) affixed to a spindle motor for rotation at a constant high speed.
An array of vertically aligned data transducing heads are controllably positioned by an actuator to read data from and write data to tracks defined on the recording surfaces. An actuator motor rotates the actuator to move the heads across the disc surfaces. The heads are configured to be hydrodynamically supported adjacent the disc surfaces by fluidic pressures established by the high speed rotation of the discs.
It is generally desirable to enclose the heads and recording media in a sealed housing to protect these components from the deleterious effects of fluid-borne contaminants from the surrounding atmosphere. Some device designers have proposed hermetically sealed designs that contain a lower density atmosphere within the housing, such as an inert gas (helium, etc.), to reduce windage and vibration effects and achieve higher levels of operational performance.
With the continued demand for higher performance data storage devices, there remains a continual need for improved housing seal configurations. It is to these and other improvements that the claimed invention is generally directed.
As embodied herein and as claimed below, the present invention is generally directed to an apparatus and method for sealing a housing, such as a housing of a data storage device.
In accordance with preferred embodiments, opposing first and second housing members are provided, with the first member having a groove of selected depth and width. A substantially planar member is affixed to the first housing member and has a compliant portion adjacent the groove.
In some embodiments, the compliant portion is cantilevered so as to be supported at one end and to project partially across the groove. In other embodiments, the compliant portion is supported at both ends and completely spans the groove.
A sealing material is compressed between the compliant portion and the second housing member to form a seal therebetween. During compression of the sealing material, the compliant portion deflects into the groove to apply a compliant force against the sealing material.
The sealing material is preferably characterized as a form in place gasket (FIPG). A layer of elastomeric material is further preferably disposed between the planar member and the first housing member to provide constrain layer damping of the first housing member.
These and various other features and advantages which characterize the claimed invention will become apparent upon reading the following detailed description and upon reviewing the associated drawings.
While the claimed invention has utility in any number of different applications,
The housing 101 provides a controlled interior environment for various constituent components of the device 100, including a spindle motor 106 which rotates a number of data recording discs 108, and an actuator 110 which supports a corresponding array of data transducing heads 112 adjacent the disc surfaces.
The actuator 110 is controllably positioned by a voice coil motor (VCM) 114 which aligns the heads 112 with tracks (not shown) defined on the disc surfaces. A flex circuit assembly 116 provides electrical communication paths between the actuator 110 and control electronics supported on a printed circuit board assembly (PCBA) 118 mounted to the underside of the base deck 102.
Of particular interest to the present discussion is the manner in which the top cover 104 mates with the base deck 102 to seal the housing 101. A first preferred embodiment is shown in
The groove 122 circumferentially extends adjacent a peripheral edge 126 of the top cover 104, as shown in
A substantially planar member 128 is attached to the first surface 120 of the top cover 104. The member 128 is also preferably formed from sheet stock aluminum and includes a compliant portion 130. The compliant portion 130 is characterized as a cantilevered distal end which projects partially across the width of the groove 122 as shown.
The compliant portion 130 supports a suitable sealing material 132, such as a bead of viscous elastomeric material that is controllably applied to provide a form in place gasket (FIPG). Other sealing materials and configurations can be used, however, such as a preformed gasket having a selected cross-sectional shape, such as circular (i.e., a hollow or solid o-ring).
The base deck 102 in
During compression of the sealing material 132, the compliant portion 130 deflects upwardly into the groove 122, thereby exerting a compliant force downwardly against the sealing material 132 to support the sealing material. The groove 122 advantageously provides localized structural rigidity to the base of the cantilevered portion 130 at the point where deflection of the portion 130 substantially begins. The groove 122 also provides the necessary clearance for the portion 130 to deflect.
The amount of compliant force applied to the sealing material 132 by the member 128 will depend upon a number of factors, including the dimensions, orientations and materials used. Thus, different amounts of deflection and force can be provided as desired depending upon the requirements of a given application.
Upon compression of the sealing material 132, the compliant portion 146 deflects, or bows into the groove 122, thereby applying a compliant force upon the sealing material 132. Because the portion 146 is secured at both ends instead of just one end as with the cantilevered portion 130, the portion 146 will tend to be substantially stiffer than the cantilevered end 130. Thus, use of a thinner or otherwise more compliant material may be desirable for the member 144 as compared to the member 128. As before, remaining portions of the member 144 can be used to provide constrain layer damping of the top cover 104.
It will be noted that the various preferred embodiments presented herein provide certain advantages over the prior art. The embodiments are easily manufactured and accept tolerance variations within ranges that are readily achievable using standard manufacturing processes.
The compliant portions 130, 146 supply compliant support to the sealing material so that lower compression forces can be utilized during the clamping of the top cover to the base deck. This eliminates the need for the addition of expensive structural members or extra material as in prior art designs.
The groove 122 advantageously provides enhanced structural rigidity to support the controlled deflection of the compliant portion 130, as well as to provide clearance for such deflection while maintaining the desired sealing between the interior and the exterior of the housing.
Also, the need to machine or otherwise precision form a path for a preformed sealing gasket (such as in the base deck) can be eliminated, as well as the sorting of various housing members during the manufacturing process to locate base deck/top cover pairs with desired dimensions and/or tolerances.
It will now be understood that the present invention (as embodied herein and as claimed below) is generally directed to an apparatus and method for sealing a housing.
In accordance with some preferred embodiments, the apparatus comprises opposing first and second housing members (such as 102, 104), the first member having a groove (such as 122) of selected depth and width (such as D and W in
A sealing material (such as 132) is compressed between the compliant portion and the second housing member to form a seal therebetween, wherein the compliant portion deflects into the groove to apply a compliant force against the sealing material.
In some embodiments, the compliant portion is characterized as a cantilevered distal end (such as 130) of the planar member (such as 128) which is supported at one end of the groove and projects partially across the width of the groove. In other embodiments, the compliant portion is characterized as a medial portion (such as 146) of the planar member (such as 144) which is supported at opposing ends of the groove and projects completely across the width of the groove.
Preferably, a layer of elastomeric material (such as 142) is disposed between the planar member and the first housing member to provide constrain layer damping of the first housing member. Moreover, the first housing member comprises a substantially planar first surface (such as 120) to which the planar member is attached. The sealing material is preferably characterized as a form in place gasket (FIPG).
In accordance with other preferred embodiments, the method preferably comprises providing opposing first and second housing members (such as 102, 104), the first housing member having a groove (such as 122) of selected depth and width (such as D and W in
The method further preferably comprises compressing a sealing material (such as 132) between the compliant portion and the second housing member so that the compliant portion deflects into the groove to apply a compliant force against the sealing material.
The method further preferably comprises applying the sealing material as a bead to a selected one of the compliant portion and the second housing member to form a form in place gasket (FIPG). In some preferred embodiments, the compliant portion of the providing step is characterized as a cantilevered distal end (such as 130) which is supported at one end of the groove and projects partially across the width of the groove. In other preferred embodiments, the compliant portion of the providing step is characterized as a medial portion (such as 146) of the planar member which is supported at opposing ends of the groove and projects completely across the width of the groove.
The method further preferably comprises disposing a layer of elastomeric material between the planar member and the first housing member to provide constrain layer damping of the first housing member.
For purposes of the appended claims, the recited “first means” will be understood to correspond to at least the sealing material 132, the groove 122 and the substantially planar members 128, 144 with respective compliant portions 130, 146 as shown in
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 detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements 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. For example, the particular elements may vary depending on the particular application of the housing without departing from the spirit and scope of the present invention.
In addition, although the embodiments described herein are directed to the sealing of a data storage device housing, it will be appreciated by those skilled in the art that the claimed subject matter is not so limited, but rather extends to any number of different housing applications.
