Abstract:
A flexible cable assembly (FCA) has a flexible cable, first and second brackets attached to the flexible cable, and a band for holding the first and second brackets while the flexible cable is folded back and the first and second brackets overlap. The band is detachably mounted to the first and second brackets to facilitate efficient manufacturing and disassembly methods. The FCA may be implemented at various manufacturing stages including the head suspension assembly (HSA) or the entire hard disk drive (HDD) assembly.

Description:
1. Technical Field 
     The present invention relates generally to the internal structure of a hard disk drive (HDD), and a method of manufacturing and disassembling the HDD. More particularly, the present invention relates to a method of properly supporting an HDD flexible cable. 
     2. Description of the Related Art 
     In prior art, there is no structure that can properly support a flexible cable that has been folded back while facilitating attachment and detachment in a hard disk drive (HDD). 
     SUMMARY OF THE INVENTION 
     A flexible cable assembly (FCA) has a flexible cable, first and second brackets attached to the flexible cable, and a band for holding the first and second brackets while the flexible cable is folded back and the first and second brackets overlap. The band is detachably mounted to the first and second brackets to facilitate efficient manufacturing and disassembly methods. The FCA may be implemented at various manufacturing stages including the head suspension assembly (HSA) or the entire hard disk drive (HDD) assembly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a hard disk drive (HDD); 
     FIG. 2, which includes a plan view (FIG. 2A) and several perspective views (FIGS. 2B to  2 E), illustrates a head suspension assembly (HSA); 
     FIG. 3 is a perspective view of a flex cable assembly (FCA)  50 ; 
     FIG. 4 is a plan view of a flexible cable  60 ; 
     FIG. 5 is a plan view of the flex cable assembly (FCA)  50 ; 
     FIG. 6 is an enlarged plan view of part of the flex cable assembly (FCA) before folding back a flexible cable  60 ; 
     FIG. 7 is an enlarged top view of part of the flex cable assembly (FCA) after folding back the flexible cable  60 ; 
     FIG. 8 is a perspective view of the head suspension assembly (HSA)  30 ; 
     FIG. 9 is a plan view showing the head suspension assembly (HSA)  30  in the hard disk drive (HDD)  10 ; 
     FIG. 10 is a perspective view showing the case of causing a second bracket  80  to have hooked portions as supposition; 
     FIG. 11 is an enlarged perspective view illustrating the need to attach flex cable assembly (FCA)  50  to head gimbal assembly (HGA)  32  with attaching screw  44  before folding back flexible cable  60 ; 
     FIG. 12, which includes a perspective view (FIG. 12A) and a plan view (FIG.  12 B), illustrates the need to attach flex cable assembly (FCA)  50  to head gimbal assembly (HGA)  32  with attaching screw  44  before folding back the flexible cable  60 ; 
     FIG. 13 is a perspective view showing that a band  90  is utilized separately from the first bracket  70  and second bracket  80 ; 
     FIG. 14, which includes a perspective view and a plan view, illustrates that band  90  can be provided with both hooked portions  92  and support portions  96 ; 
     FIG. 15 is a plan view showing grooves  94  formed in the band  90 ; 
     FIG. 16 is a perspective view showing protrusions provided on the second bracket side; and 
     FIG. 17 is a schematic diagram comparing the case where only band  90  is bent (FIG.  17 A), and the case where band  90  is bent while attached to flexible cable  60  (FIG.  17 B). 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a perspective view of a hard disk drive (HDD)  10  with a cover  18  removed to show its internal state. A disk  14  is attached to a base  12  so that it is rotatable. Also, a head suspension assembly (HSA)  30  is attached to the base  12  so that it can have access to a predetermined position on the disk  14  in the radial direction of the disk  14 . 
     FIGS. 2A E shows a plan view (FIG. 2A) and perspective views (FIGS. 2B to  2 E) of the head suspension assembly (HSA)  30 . The perspective views are taken in various directions. The head suspension assembly (HSA)  30  includes a head gimbal assembly (HGA)  32 , a coil support  38 , and a flex cable assembly (FCA)  50 . 
     The head gimbal assembly (HGA)  32  and the coil support  38  are fixedly attached with each other, they being mounted on the base  12  so that they are rotatable on a shaft  40  (also see FIG.  1 ). Current is applied to the coil portion of the coil support  38  through the flex cable assembly (FCA)  50 . The coil support  38  rotates the head suspension assembly (HSA)  30  in cooperation with a magnetic field given by a voice coil motor (VCM) assembly  16  (FIG.  1 ). With this rotation, the head suspension assembly (HSA)  30  can have access to a desired position on the disk  14 . 
     With respect to recording data on the disk  14  and reading data from the disk  14 , a signal is given to a head  34  positioned on the pointed end of a suspension  36  and a signal is taken from the head  34 . The data recording and reading signals are also transmitted through the flex cable assembly (FCA)  50 . 
     FIG. 3 is a perspective view of the flex cable assembly (FCA)  50 . The flex cable assembly (FCA)  50  includes a flexible cable  60 , a first bracket  70 , a second bracket  80 , a bracket band (hereinafter referred to as simply a “band”)  90 , arm electronics (AE)  100 , other electrical parts  110 , a vertical bracket  120 , a base bracket  130 , and a connector  140 . There are cases where the flex cable assembly (FCA)  50  does not include the band  90  before the band  90  is mounted. 
     FIG. 4 is a plan view of the flexible cable  60 . The whole flexible cable  60  can be cut into a sheet, which can include a wiring pattern therein. One end  62  of the flexible cable  60  is connected to both the head gimbal assembly (HGA)  32  and the coil support  38 , while the other end  66  is mounted on the base  12  (FIG.  1 ). The flexible cable  60  can be folded back to a mountain side or a valley side at positions indicated by dotted lines. That is, the flexible cable  60  can also be folded back between positions at which the first bracket  70  and the second bracket  80  will be attached, indicated by  64 . 
     FIG. 5 is a plan view of the flex cable assembly (FCA)  50 . The first bracket  70 , second bracket  80 , band  90 , AE  100 , other electrical parts  110 , vertical bracket  120 , base bracket  130 , and connector  140  are attached to the flexible cable  60  that has been cut out into a sheet shape over its whole. Note that in order to attach these components to the flexible cable  60 , it is easy for those having skill in this field to adopt various methods, such as adhesion, welding, and soldering. 
     The FCA  50  can be assembled three-dimensionally as shown in FIG. 3, by folding back it to a mountain side or a valley side at positions indicated by dotted lines in FIG.  4 . As a result of assembly, the connector  140  attached to the other end  66  of the flexible cable  60  is moved to a plane (indicated by a dotted line in FIG. 3) opposite from the plane shown in FIG. 4 or  5 . Also, the flexible cable  60  can be assembled perpendicular to the base bracket  130 , by assembling the vertical bracket  120  perpendicularly with respect to the base bracket  130  (FIG.  3 ). 
     FIG. 6 is an enlarged plan view of part of the flex cable assembly (FCA)  50  before folding back the flexible cable  60 . As shown in this figure, the first bracket  70  and the second bracket  80  are separated through the flexible cable  60 , so that the portion  64  between the first bracket  70  and the second bracket  80  can be folded back. 
     FIG. 7 is an enlarged top view of part of the flex cable assembly (FCA)  50  after folding back the flexible cable  60 . According to this figure, it can be seen that the first bracket  70  and the second bracket  80  overlap each other with the flexible cable  60  folded back. The first bracket  70  and the second bracket  80  are held because the band  90  is interposed therebetween. 
     Also, since the band  90  is interposed between the first bracket  70  and the second bracket  80 , the second bracket  80  and the flexible cable  60  attached thereto are spaced from the AE  100 . Furthermore, the first bracket and the second bracket  80  are held while maintaining a predetermined angle formed therebetween. 
     The reason why such a configuration becomes necessary is related to the fact that the AE  100  and the other electrical parts  110  are provided near the head suspension assembly (HSA)  30 . Disposing electrical parts at a position as near as possible with respect to the head  34  is advantageous in function. For instance, there are cases where only a weak current can be taken out from the head  34 , so it is advantageous to apply current to a preamplifier circuit within the AE  100  in an early stage. In practice, the AE  100  and the other electrical parts  110  occupy a considerable area on the first bracket  70 . 
     FIG. 8 is a perspective view of the head suspension assembly (HSA)  30  and is also an enlarged view showing one of the perspectives of FIG.  2 . From FIG. 8, both a position at which the flex cable assembly (FCA)  50  is attached to the head gimbal assembly (HGA)  32  and the coil support  38  and a position at which the flexible cable  60  is folded back are understood. 
     FIG. 9 is a plan view showing the relationship that the head suspension assembly (HSA)  30  is disposed within the hard disk drive (HDD)  10 . The flexible cable  60  is in the shape of S. The head suspension assembly (HSA)  30  has not had access to a desired position on the disk  14  (when the head suspension assembly (HSA)  30  is at a desired position on the disk  14 , it is in a so-called loaded state). That is, the head suspension assembly (HSA)  30  is at an unloaded position (or in a so-called unloaded state). It can be understood that the S shape of the flexible cable  60  is deeply related to the fact that the first bracket  70  and the second bracket  80  are held while maintaining a predetermined angle formed therebetween. 
     If the head suspension assembly (HSA)  30  has access to a desired position on the disk  14 , the radius of curvature of the arc drawn as letter S will vary correspondingly. That is, the flexible cable  60  produces a variable bias force. This bias force produces a force having influence on the rotation of the head suspension assembly (HSA)  30  about the shaft  40 , namely, moment of rotation. If such moment of rotation changes largely, there is a possibility that, when the head suspension assembly (HSA)  30  has access to a predetermined position on the disk  14 , it will cause an erroneous operation to occur. Therefore, in order to ensure the data access reliability of the HDD, a less change in the moment of rotation is desirable. 
     For this reason, careful consideration must be given to the attachment position of the HSA to the base, the access range of the HSA, and the seek angle (angle of rotation) between the shaft  40 , which is the center of attachment of the HSA, and the disk  14 , when they are designed. That is, in consideration of them, 15 degrees, which is the angle between the first bracket and the second bracket, has been determined. Note that it is easy f or those skilled in the art to adopt various angles between the first bracket  70  and the second bracket  80  in other various HDDs. 
     It is understood that in order to utilize the space within the HDD  10  efficiently, the flexible cable  60  has to be folded back at the position where it is attached to the HGA  30 . If the flexible cable  60  is folded back as shown in FIG. 9, the flexible cable  60  will have substantially the same effect as the flexible cable  60  is attached at a position as near as possible with respect to the shaft  40  that is the center of rotation of the head suspension assembly (HSA)  30 . That is, the arm length to the root of the flexible cable  60  producing moment of rotation is shortened, whereby the moment of rotation can be suppressed to a small value. Also, if the S-shaped portion formed by the flexible cable  60  is lengthened, a change in the radius of curvature can be made relatively small. 
     Here, the reason that, as shown in FIG. 6, the flex cable assembly (FCA)  50  is provided with the first bracket  70  and the second bracket  80  will be set forth. Although also evident in the fact that the flexible cable  60  can be folded back at the portion  64  between the first bracket  70  and the second bracket  80 , it cannot be the that the flexible cable  60  alone has sufficient rigidity with respect to bending. Rigidity is also necessary for fixing the flexible cable  60  to other components. Hence, if the first bracket  70  and the second bracket  80  are provided, at least the portions provided with these brackets will ensure rigidity. 
     The first bracket  70  and the second bracket  80  are held with the brackets engaging each other, while they need to be easily mounted from the standpoint of manufacturing and easily detached from the standpoint of disassembly. In order to meet both the mounting function and the detaching function, it is considered that the second bracket  80  is provided with hooked portions, as assumed in FIGS. 10A-B, for example. 
     However, if the second bracket  80  is provided with hooked portions, the second bracket  80  will not be in flat shape. Considering the convenience of the manufacturing that the second bracket  80  is attached to the cable  60  by adhesion, it is desirable that the second bracket  80  be as flat as possible. It is desirable to remove a protruding portion from the second bracket  80 , such as the hooked portion assumed in FIGS. 10A-B, as much as possible. It is assumed that the first bracket is provided with hooked portions and handled as a flat shape. 
     It is also desirable that the first bracket  70  be in flat shape. The reason is that electrical parts, such as AE  100  or the like, are mounted on the first bracket  70 . More specifically, access operation, such as soldering or the like, becomes necessary for the electrical connection between the one end  62  of the flex cable assembly (FCA)  50  and the head gimbal assembly (HGA)  32  (see an arrow in FIG.  11 ). In performing such access operation, a protruding portion such as a hooked portion is physically a hindrance and is therefore undesirable. 
     Also, there are cases where either the hook shape of the first bracket  70  or the hook shape of the second bracket  80  is damaged by forcible attachment or detachment. In such a case, not only either of the first and second brackets  70 ,  80  but the flexible cable  60  to which they are attached, namely, the entire flex cable assembly (FCA)  50  has to be exchanged. 
     As shown in FIGS.  11  and  12 A-B, there is a need to attach the flex cable assembly (FCA)  50  to the head gimbal assembly (HGA)  32  by means of an attaching screw  44  before folding back the flexible cable  60 . The threaded portion of the attaching screw  44  projects from the first bracket  70 . The threaded portion of the attaching screw  44  is spatially avoided because of the existence of the band  90 , as in the description of FIG. 7. A portion fulfilling such a function is called the support portion of the band  90 , a detailed description thereof being made later. 
     As shown in FIG. 13, the present invention is provided with the band  90  as a component separate from the first and second brackets  70 ,  80 . Using this band  90 , the band  90  is mounted while the first bracket  70  and the second bracket  80  are being overlapped with each other, whereby the first bracket  70  and the second bracket  80  can be held. Since the band  90  is employed as a separate component, attachment is easy and detachment is also easy. Although, in FIG. 13, the band  90  is drawn as a component separate from the second bracket  80 , the band  90  and the second bracket  80  can be held as one body, as described infra. 
     A description will next be made of which manufacturing stage the attachment or detachment of the band  90  should be performed at. This operation may be performed at the stage of forming the flex cable assembly (FCA)  50  (FIG.  3 ). It may also be performed at the stage of forming the head suspension assembly (HSA)  30  (FIGS. 2,  8  and  13 ). Furthermore, it may be performed at the stage of finally assembling the head suspension assembly (HSA)  30  into the base  12  of the hard disk drive (HDD)  10  (FIGS.  1  and  9 ). 
     For instance, consider the stage of finally assembling the head suspension assembly (HSA)  30  into the base  12  of the hard disk drive (HDD)  10 . Attaching the other end  66  of the flexible cable  60  to the base  12  through the connector  140  has previously been set forth. At this time, the connector  140  is on the back side, as shown in FIG. 3, so that the connection of the connector  140  to the base  12  and the detachment of the connector  140  from the base  12  are extremely easy and can be performed even before band attachment or even after band attachment, namely, at any stage. That is, attachment of the band  90  is realizable in the unit of head suspension assembly (HSA)  30  or in the unit of the entire hard disk drive (HDD) assembly. 
     As shown in FIGS. 14A-B, the band  90  can also be provided with both a hooked portion  92  and a support portion  96 . The hooked portion  92  is a portion engageable with the first bracket  70 . If the support portion  96  is formed to have a certain angle, as shown in FIG. 14, the second bracket  80  and the flexible cable  60  attached thereto can spatially avoid the attaching screw  44  and the AE  100 . The first bracket  70  and the second bracket  80  are held while maintaining about an angle of 15° formed therebetween, which is a predetermined angle. When the band  90  does not engage the first bracket  70 , the band  90  and the second bracket  80  can be held as one body by the engagement between the grooves  94  of the band  90  and the protrusions  82  provided on the side of the second bracket  80 . If done in this manner, there is no need to archive only the band  90  as a separate component. 
     FIGS. 17A-B is a schematic diagram comparing the case where the band  90  alone is bent (FIG. 17A) and the case where the band  90  is bent with the band  90  attached to the flexible cable  60  (FIG.  17 B). For example, if at least a portion of the band  90  is made of elastically deformable material, that portion will be bent. As a result, the hooked portions  92  of the band  90  are widened and clamp the first bracket  70 , whereby engagement becomes possible. Of course, it is easy for those having skill in this field to adopt other various methods of engagement. 
     However, from FIGS. 17A-B it follows that the case in FIG. 17A is more advantageous in bending than that in FIG.  17 B. The reason is that bending is not restricted by the flexible cable  60 . That is, in the case of FIG. 17B, the bending rigidity of the flexible cable  60  increases excessively. Also, in the case of FIG. 17A, the hooked portions  92  can be provided lengthwise, so they can firmly engage (or clamp) the first bracket  70 . Even if there were a great vibration or shock, disengagement would be difficult. On the other hand, in the case of FIG. 17B there is even a possibility of damaging the grooves  94 . The case of FIG. 17B is also considered equivalent to the case (FIGS. 10A-B) where hooked portions are provided on the side of the second bracket as supposition. The reason is that bending rigidity increases excessively by the amount that the second bracket  80  has a wider width than the band. 
     The first bracket  70 , the second bracket  80 , and the band  90  employ plastic material. The reason is that the plastic material can be formed into a complicated shape; the plastic material is light in weight and also has elasticity; and the plastic material is suitable for mass production. ULTEM (trademark of GE. Plastic Co.) consisting of polyether imide (PEI) was employed as a suitable material. More particularly, a grade of ULTEM1000 was used. If it is desirable to change the coefficient of elasticity, those having skill in this field may adopt other grades. 
     In the reasons why the aforementioned material was used, heat-resisting property has also been taken into consideration. The reason is that the attachment of the AE  100  and the other electrical parts  110  to the first bracket  70  of the flex cable assembly (FCA)  50  and the attachment of the flexible cable  60  to head gimbal assembly (HGA)  32  are performed by soldering. Furthermore, if the materials for the first bracket  70 , the second bracket  80 , and the band  90  are all the same, they will fit each other, because they engage and physically contact. 
     In order for the band to obtain sufficient elasticity, it is considered that the thinnest possible band  90  is better. However, in practical production, if the thickness is less than 0.3 mm, resin will not easily flow into a metal mold and therefore stable products cannot be made. On the other hand, it has been confirmed that even a thickness of 0.3 mm fulfills a sufficient function. 
     It should be apparent to those skilled in the art to adopt other substitute plastic materials and other proper thickness with respect to the band.