Establishing a housing seal using a flex assembly
Method and apparatus for sealing a housing, and a housing sealed using the same. A peripherally extending flex seal assembly includes a heating member formed of an elongated conductor embedded within a flexible, thin-film dielectric ribbon. The flex seal assembly is placed on a first housing member and a second, mating housing member is placed on the flex seal assembly. Preferably, fasteners are used to affix the first and second housing members to compress the flex seal assembly therebetween. Current is applied to the heating member to fuse at least one ring of sealing material and form a corresponding number of hardened seal joints. The seal joints can be discrete rings to allow the formation of a hermetic housing seal. The seal joints can alternatively be arranged in a continuous spiral to form an elongated diffusion path between the interior of the housing and the exterior environment.
The claimed invention relates generally to the field of mechanical enclosures and more particularly, but not by way of limitation, to an apparatus and method for sealing a housing, such as a housing of a data storage device.
BACKGROUNDDisc 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 control the interior fluidic environment within a data storage device housing. Seals are often employed to prevent the ingress of contaminants from the external environment. Moreover, some device designers have proposed hermetically sealed designs that utilize a lower density atmosphere, such as an inert gas (helium, etc.), to allow the device achieve higher levels of operational performance.
Disc drive designers are constrained by a number of factors, including continually reduced form factors and internal clearance issues, to provide effective internal fluidic control. With the continued demand for higher performance data storage devices, there remains a continual need for improved housing configurations, and it is these and other improvements that the claimed invention is generally directed.
SUMMARY OF THE INVENTIONAs 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 one embodiment, the housing is formed of opposing, substantially planar first and second housing members and a peripherally extending flex seal assembly interposed between the housing members. The flex seal assembly comprises a flexible, thin-film heating member.
Dissipation of heat from current applied to the heating member causes one or more rings of sealing material to fuse to at least the first housing member. This results in the formation of a corresponding number of hardened seal joints at the seal assembly/housing interface. The sealing material preferably comprises solder or a low permeable, thermoset adhesive.
Preferably, the heating member comprises an elongated conductor, characterized as an electrically conductive trace, which is embedded within a flexible, thin-film dielectric ribbon. At least one fastener is preferably used to affix the first housing member to the second housing member and compress the flex seal assembly therebetween.
In some embodiments, the resulting seal joints are arranged into a plurality of nested, discrete rings each in a noncontacting relationship with the remaining rings. This facilitates the formation of an effective hermetic seal between the interior of the housing and the exterior environment.
In other embodiments, the resulting seal joints are arranged as a continuously extending spiral. When the opposing ends of the spiral are configured to be open to the interior of the housing and the exterior environment, respectively, an extremely long, elongated diffusion path can be created that extends along the gaps between adjacent joints, permitting pressure equalization and contaminant entrapment between the interior and exterior environments.
Preferably, a first set of the concentric rings of sealing material is placed on a first side of the heating member to fuse with the first housing member. A second set of the concentric rings of sealing material is placed on an opposing, second side of the heating member to fuse with the second housing member.
In another embodiment, a flex seal assembly is provided as described above to establish a seal between opposing first and second housing members.
In another embodiment, a housing seal is formed by providing opposing, substantially planar first and second housing members, placing a flex seal assembly as described above between the first and second housing members, and applying current to the heating member to fuse the one or more rings of sealing material to at least the first housing member to form a corresponding number of hardened, concentric seal joints.
The method further preferably comprises a step of installing at least one fastener to affix the first housing member to the second housing member to compress the flex seal assembly therebetween prior to the applying current step.
The housing is subsequently unsealed by reapplying current to the heating member to loosen the sealing material, and removing the second housing member from 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.
BRIEF DESCRIPTION OF THE DRAWINGS
The device includes an enclosed housing 101 which defines an internal environment for the drive. The housing 101 is formed by a pair of substantially planar housing members including a base deck 102 and a top cover 104 (shown in partial cut-away in
The base deck 102 supports a spindle motor 106 which rotates a plurality of data storage discs 108 at a constant high speed. A rotary actuator 110 supports a number of data transducing heads 112 adjacent the disc surfaces. The heads 112 are hydrodynamically supported adjacent the disc surfaces via recirculating fluidic currents established by the high speed rotation of the discs 108.
The actuator 110 is pivotally rotated by an actuator motor 114, preferably characterized as a voice coil motor, VCM. As the actuator 110 rotates, the heads 112 are brought into alignment with data tracks (not shown) defined on the disc surfaces. A plenum assembly 116 channels fluidic currents through a pass-through recirculation filter (not shown) and further accommodates a relatively large block of adsorbent filtering material (also not shown).
Interposed between the housing members 102, 104 is a flex seal assembly 120 which is configured to establish a seal against the exterior environment outside the device 100. Preferably, the seal is characterized as a hermetic seal so that, upon sealing, the housing 101 is supplied with an inert gas atmosphere (e.g., helium) at a selected atmospheric pressure. The seal assembly 120 retains the internally contained fluid and further prevents the ingress of fluid-borne contaminants from the external environment for the operational life of the device 100.
With reference to
A tab 132 projects from the member 126 so as to be accessible from the exterior of the housing 101 upon installation of the flex seal assembly 120 between the housing members 102, 104. The tab 132 supports a pair of electrically conductive pads 134 placed in electrical communication with opposing ends 136 of the embedded conductor 128. The pads 134 facilitate interconnection with electrical contacts from a suitable power source (not shown) to pass current along the length of the conductor 128.
As shown in
Preferably, each of the concentric rings 140 is a closed, discrete ring which is separated from the remaining rings by an intervening circumferentially extending gap. That is, the innermost ring is nested within and surrounded (in a noncontacting relationship) by the next innermost ring, and so on.
In an alternative embodiment, the concentric rings of sealing material 140 are formed as a continuous spiral which makes multiple adjacent loops around the periphery of the seal assembly 120, such as represented in
As mentioned above, application of sufficient current to the conductor 128 causes the sealing material 140 to undergo a sufficient increase in temperature to transition to a viscous, flowable state and fuse to the facing housing member. Upon cooling, a resulting series of hardened seal joints 142 are formed at the boundary interfaces, as represented in
Preferably, the sealing material 140 is solder, the base deck 102 and top cover 104 are stamped or cast aluminum, and gold or similar plated features (not shown) are provided on the base deck 102 and top cover 104 to facilitate adequate wetting and attachment between the flex seal and the housing members to provide a hermetic seal through the cross-sectional width (indicated by arrow 144) in each of the sealing joints 142. The flex circuit 130 can likewise be plated with gold or a similar material (not shown) to achieve the requisite “wetting” between the flex circuit 130 and the housing members.
Retention grooves such as shown at 155, 156 can be advantageously used to retain and locate the sealing material 140. One or more alignment pins 157 and corresponding pin apertures 158, 159 can be utilized to ensure alignment of the sealing material 140 with the conductor 128.
To summarize the foregoing discussion,
At step 162, opposing first and second housing members (such as 102, 104) and a flex seal assembly (such as 120) are provided. The flex seal assembly 120 is placed onto the first housing member (in this case, the base deck 102) at step 164. Appropriate keying features can be provided in the seal assembly and/or housing member (such as the pin 158) to ensure correct alignment and retention of the respective members in the desired orientation.
The second housing member (top cover 104) is next placed onto the flex seal assembly 120 at step 166. Preferably, fasteners (such as 122) are installed during this step to mechanically affix the second housing member to the first housing member and compress the flex seal assembly therebetween.
Current is applied to the flex seal assembly 120 at step 168 to fuse the sealing material 140 to the housing members. This is preferably carried out by robotically controlled contacts which locate and engage the conductive pads 134 on the tab 132 and apply the appropriate current for a specified period of time sufficient to ensure complete heating and flow of the sealing material 140. This step further contemplates the removal of the contacts and a short cooling time during which the heated sealing material hardens to form the corresponding concentric rings of seal joints 142 shown in
As mentioned above, the rings of sealing material 140 are preferably configured to form a hermetic seal so as to fully isolate the interior of the housing 101 from the exterior environment during the operational life of the device 100. In this case, an additional step shown at 170 is preferably carried out during which the existing (e.g., ambient air) atmosphere is evacuated and replaced with the desired (e.g., helium) atmosphere. The process then ends at step 172.
It is contemplated that the seal formed by the routine 160 of
At step 182, the aforementioned fasteners 122 used to mechanically affix the top cover to the base deck are removed, and sufficient current is applied to the pads 134 to soften the sealing material 140. This loosens the seal so that the second housing member (top cover) can be removed at step 184, permitting the desired evaluation and/or rework steps.
While the flex seal assembly 120 can be configured in certain applications to be reusable, it is contemplated that in most cases the assembly will be a onetime use component. Thus, after the evaluation and/or rework steps are completed, the originally installed flex seal assembly is discarded and a new, replacement flex seal assembly is installed at step 186.
As before, the second housing member is again affixed to the first housing member at step 188, current is applied to the second, replacement flex seal assembly to reestablish the housing seal at step 190, and as desired, the housing 101 is filled with the appropriate fluid at step 192. The process then ends at step 194.
It will be recognized that the presence of the external tab 134 readily facilitates the ability to carry out the routine of
Advantages of the flex seal assembly 120 as described herein include the ability to provide a low cost, easily manufacturable seal suitable for use in hermetic designs. As desired, the use of multiple rings enhances the capability of the seal to retain a low density inert atmosphere.
The use of solder (or other low permeable sealing material) generally provides a superior seal as compared to other materials such as formed-in-place elastomeric gaskets. Photolithography and similar material deposition techniques can be used to form the various features of the flex seal assembly 120 in a precise and cost effective manner.
The flex seal assembly is contemplated as providing a hermetic seal solution that costs significantly less than existing solutions that rely on precision-formed metal c-shaped or similar gasket seals and precision machined mating surfaces. The flexible nature of the flex seal assembly generally makes the assembly less susceptible to handling damage as compared to these other hermetic seal solutions.
While preferred embodiments contemplate that the flex seal assembly provides a complete, hermetic seal so that nominally no fluidic or contaminant migration occurs across the seal boundary for the life of the device 100, as mentioned above the concentric rings can be alternatively arranged in a continuous spiral or similar fashion (
Such a path could conceivably be several linear feet long; for example, a 3½ inch form factor device with about a 20 inch circumference and having a diffusion path with seven passes (between eight concentric rings) would provide an overall diffusion tube length of about 140 inches, or about twelve feet. This would provide a significantly greater wall surface area to entrap contaminants within the diffusion path as compared to existing diffusion path designs. Thus, it will be noted that the flex seal assembly 120 has utility in both hermetically sealed and non-hermetically sealed applications.
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 (such as a housing 101 of a data storage device 100).
In one embodiment, the housing is formed of opposing, substantially planar housing members (such as 102, 104). A peripherally extending flex seal assembly (such as 120) is interposed between the first and second housing members and comprises a flexible, thin-film heating member (such as 126) and at least one ring of sealing material (such as 140) disposed adjacent the heating member. The sealing material is preferably solder or a low permeable, thermoset adhesive.
Dissipation of heat from current applied to the heating member causes the at least one ring of sealing material to fuse to at least the first housing member to form a corresponding number of hardened seal joints (such as 142).
Preferably, the heating member comprises an elongated conductor (such as 128) embedded within a dielectric ribbon (such as 130). At least one fastener (such as 122) is preferably used to affix the first housing member to the second housing member and compress the flex seal assembly therebetween.
In some embodiments, the hardened seal joints are arranged into a plurality of nested, discrete rings each in a noncontacting relationship with the remaining rings, thereby facilitating the formation of a hermetic seal between the interior of the housing and the exterior environment. In other embodiments, the hardened seal joints are arranged as a continuously extending spiral to facilitate the creation of an elongated diffusion path (such as 146) to permit pressure equalization and contaminant entrapment between the interior and exterior environments.
Preferably, a first set of the rings of sealing material is placed on a first side of the heating member to fuse with the first housing member. A second set of the rings of sealing material is placed on an opposing, second side of the heating member to fuse with the second housing member (such as illustrated in
In another embodiment, a flex seal assembly (such as 120) is provided as described above to establish a seal between opposing first and second housing members (such as 102, 104).
In another embodiment, a housing seal is formed by providing opposing, substantially planar first and second housing members (such as by step 162), placing a flex seal assembly as described above between the first and second housing members (such as by steps 164, 166), and then applying current to the heating member to fuse one or more rings of sealing material to at least the first housing member to form a corresponding plurality of hardened, concentric seal joints (such as by step 168).
The method further preferably comprises a step of installing at least one fastener to affix the first housing member to the second housing member to compress the flex seal assembly therebetween prior to the applying current step.
The housing is subsequently unsealed by reapplying current to the heating member to loosen the sealing material (such as by step 182), and removing the second housing member from the first housing member (such as by step 184).
For purposes of the appended claims, the recited means for sealing will be understood consistent with the foregoing discussion to correspond to the disclosed flex seal assembly 120 as represented in
The further recitation of the means for sealing as establishing a diffusion path will be understood consistent with the foregoing discussion to correspond to the arrangement of the sealing material 140 of the flex seal assembly 120 into a continuously extending spiral or similar arrangement with open, opposing ends, as represented in
The recited steps for sealing will be understood consistent with the foregoing discussion to correspond to at least steps 164, 166 and 168 of
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 hermetic sealing of a data storage device housing, it will be appreciated by those skilled in the art that the housing can be used for various other types of sealed enclosures without departing from the spirit and scope of the claimed invention.
Claims
1. A sealed housing comprising:
- opposing, substantially planar first and second housing members; and
- a peripherally extending flex seal assembly interposed between the first and second housing members and comprising a flexible, thin-film heating member and at least one ring of sealing material disposed adjacent the heating member, wherein dissipation of heat from current applied to the heating member causes the at least one ring of sealing material to fuse to at least the first housing member to form a corresponding number of hardened seal joints.
2. The housing of claim 1, wherein the heating member comprises an elongated conductor embedded within a dielectric ribbon.
3. The housing of claim 2, wherein the dielectric ribbon comprises at least one layer of thin-film polyimide.
4. The housing of claim 1, further comprising at least one fastener which affixes the first housing member to the second housing member to compress the flex seal assembly therebetween.
5. The housing of claim 1, wherein the number of hardened seal joints comprises a plurality of seal joints arranged into nested, discrete rings each in a noncontacting relationship with each remaining ring.
6. The housing of claim 1, wherein the number of hardened, seal joints are arranged as a continuously extending spiral.
7. The housing of claim 1, wherein the number of hardened seal joints are configured to form a nominally hermetic seal between an interior of the housing and an exterior environment.
8. The housing of claim 7, further comprising a low density inert gas atmosphere contained within the sealed housing.
9. The housing of claim 1, wherein each of the at least one ring of sealing material is formed of solder.
10. The housing of claim 1, wherein each of the at least one ring of sealing material is formed of a low permeable, thermoset adhesive.
11. The housing of claim 1, wherein the at least one ring of sealing material comprises a first set of rings disposed on a first side of the heating member to fuse with the first housing member and a second set of rings disposed on an opposing, second side of the heating member to fuse with the second housing member.
12. The housing of claim 1, characterized as a housing of a data storage device in which a data storage medium is supported.
13. A sealed housing, comprising:
- opposing, substantially planar first and second housing members; and
- means for sealing the first and second housing members.
14. The sealed housing of claim 13, wherein the means for sealing further establishes an elongated diffusion path between an interior of the housing and an exterior environment.
15. The sealed housing of claim 13, further comprising at least one fastener which affixes the first housing member to the second housing member.
16. A flex seal assembly for establishing a seal between opposing, substantially planar first and second housing members, comprising:
- a heating member comprising an elongated conductive trace embedded within a flexible, thin-film dielectric ribbon; and
- at least one ring of sealing material disposed adjacent the heating member, wherein dissipation of heat from current applied to the heating member causes the at least one ring of sealing material to fuse to at least the first housing member to form a corresponding number of hardened seal joints.
17. The flex seal assembly of claim 16, wherein the at least one ring of sealing material is arranged so that the resulting number of hardened, concentric seal joints nominally form a plurality of nested, discrete rings each in a noncontacting relationship with each remaining ring.
18. The flex seal assembly of claim 16, wherein the number of hardened seal joints are configured to form a nominally hermetic seal between an interior of the housing and an exterior environment.
19. The flex seal assembly of claim 16, wherein the hardened seal joints are configured to form an elongated diffusion path along gaps between adjacent seal joints from an interior of the housing to an exterior environment.
20. The flex seal assembly of claim 16, wherein the at least one ring of sealing material comprises a first set of rings disposed on a first side of the heating member to fuse with the first housing member and a second set of rings disposed on an opposing, second side of the heating member to fuse with the second housing member.
21. A method for sealing a housing, comprising:
- providing opposing, substantially planar first and second housing members;
- placing a flex seal assembly between the first and second housing members, the flex seal assembly comprising a flexible, thin-film heating member; and
- applying current to the heating member to fuse at least one ring of sealing material to at least the first housing member to form a corresponding number of hardened seal joints.
22. The method of claim 21, wherein the heating member of the placing step comprises an elongated conductor embedded within a dielectric ribbon.
23. The method of claim 21, further comprising a step of installing at least one fastener to affix the first housing member to the second housing member to compress the flex seal assembly therebetween prior to the applying current step.
24. The method of claim 21, wherein the number of hardened seal joints of the applying current step are arranged into a plurality of nested, discrete rings each in a noncontacting relationship with each remaining ring.
25. The method of claim 21, wherein the number of hardened seal joints of the applying current step are configured to form a nominally hermetic seal between an interior of the housing and an exterior environment, and wherein the method further comprises steps of evacuating an existing fluid within the interior of the housing and filling the interior of the housing with an inert fluid.
26. The method of claim 21, wherein the number of hardened seal joints of the applying current step form an elongated diffusion path along gaps between adjacent seal joints from an interior of the housing to an exterior environment.
27. The method of claim 21, wherein each of the at least one rings of sealing material of the placing step are formed of solder.
28. The method of claim 21, wherein each of the at least one rings of sealing material of the placing step are formed of adhesive.
29. The method of claim 21, wherein the concentric rings of sealing material of the applying step comprise a first set of rings disposed on a first side of the heating member and a second set of rings disposed on an opposing, second side of the heating member to fuse with the second housing member so that the applying current step comprises forming the hardened, concentric seal joints between the flex seal assembly and the first housing member and between the flex seal assembly and the second housing member.
30. The method of claim 21, further in combination with a method for subsequently unsealing the housing comprising:
- subsequently applying current to the heating member to loosen the sealing material; and
- removing the second housing member from the first housing member.
31. The method of claim 21, wherein the housing is characterized as a housing of a data storage device in which a data storage medium is supported.
32. The method of claim 21, wherein the providing step further comprises providing the at least one ring of sealing material on the first housing member prior to the placing step.
33. The method of claim 21, further comprising providing the at least one ring of sealing material on the flex seal assembly prior to the placing step.
34. A sealed housing comprising opposing, substantially planar first and second housing members and a peripherally extending flex seal assembly interposed between the first and second housing members and forming a seal between the first and second housing members by steps for sealing the housing.
Type: Application
Filed: Feb 20, 2004
Publication Date: Aug 25, 2005
Inventors: Zine-Eddine Boutaghou (North Oaks, MN), Neal Gunderson (Lake Elmo, MN), Roger Hipwell (Eden Prairie, MN), Frank Bernett (Longmont, CO)
Application Number: 10/783,634