Abstract:
A method for mounting a flexible flexure, which has a slider fixed thereto and having an electro-magnetic conversion element integrally, on a load beam includes the steps of joining a main flexure, which has a junction piece for joining the load beam, to the load beam with the junction piece therebetween; inspecting characteristics by floating the electromagnetic conversion element onto a magnetic disc; when the characteristics do not satisfy a reference as a result of the inspection, removing the main flexure from the load beam by cleaving the main flexure at a cleavage part disposed in a vicinity of the junction piece; and at least one time joining a sub-flexure having no junction piece to the load beam, from which the main flexure is removed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a magnetic-head assembly system suitable for use in writing and reading means of a hard magnetic-disc drive and a manufacturing method thereof.  
         [0003]     2. Description of the Related Art  
         [0004]     A so-called magnetic-head assembly used recently in a hard disc drive (HDD), as shown in  FIG. 9 , comprises a slider  201  having an integrally formed electromagnetic conversion element, a flexure (suspension)  202  made of a flexible metallic plate and bonded to the slider  201 , and a load beam  203  with the leading edge fixed, by spot welding for example, to one end of the flexure  202 , so that a gap between an ABS (air bearing surface) of the slider  201  and the hard magnetic-disc is maintained by the balancing between an elastic force of the flexure  202  and a fluid force produced between the slider  201  and the rotating magnetic hard disc. Such a conventional magnetic-head assembly is disclosed in Japanese Unexamined Patent Application Publication No. 7-73625, Japanese Unexamined Patent Application Publication No. 10-269538, Japanese Unexamined Patent Application Publication No. 2000-21709, and Japanese Unexamined Patent Application Publication No. 2000-105913, for example.  
         [0005]     On such a kind of magnetic-head assembly, static and dynamic characteristic tests are performed before shipping.  
         [0006]     While the static characteristic test is performed by applying an external magnetic field to the slider  201  as a unit test, the dynamic characteristic test is performed in a state the flexure  202  having the slider  201  bonded thereto and being fixed to the load beam  203  is mounted on a spin stand, etc., so that the hard magnetic-disc is rotated. Since the dynamic characteristic test is final, if the result does not match a reference value, this magnetic-head assembly is regarded as defective. Even if the reason of the failure comes from the slider  201  or the flexure  202 , since it is difficult to peel the slider  201  off the flexure  202  or to remove the flexure  202  from the load beam  203 , the entire magnetic-head assembly including the load beam  203  is regarded as defective, so that it cannot be reproduced. It would appear that the slider  201  is removed from the flexure  202  so that a new slider is attached to a new flexure; however, since the flexure  202  is very thin and fragile in comparison with the load beam  203  so that if the slider  201  is to be peeled off the flexure  202  fixed to the load beam  203 , the flexure  202  is easily deflected and adhesive is difficult to be completely removed, so that the reproduction of the flexure  202  and the load beam  203  has been difficult.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention has been made in view of the conventional problems described above, and it is an object thereof to provide a magnetic-head assembly capable of reusing component parts and its production.  
         [0008]     A magnetic head assembly according to the present invention for achieving the above object comprises a flexible flexure comprising a slider fixed thereto and having an electro-magnetic conversion element integrally therewith; and a load beam for mounting the flexure, wherein the flexure comprises a junction piece protruded from an edge of the flexure for joining the load beam and a main flexure in that the junction piece is detached from the load beam by an external force pulling the flexure in the leading end direction in a state that the junction piece is joined to the load beam.  
         [0009]     According to the structure of the present invention, in the case where characteristics of the slider in the magnetic head assembly having the main flexure mounted thereon have a problem, the main flexure can be easily detached from the load beam.  
         [0010]     Moreover, according to the present invention, a sub-flexure may be joined to the load beam with the main flexure detached therefrom, so that the load beam can be reused, promoting effective use of resources.  
         [0011]     Furthermore, a magnetic head assembly according to the present invention comprises a flexible flexure comprising a slider fixed thereto and having an electro-magnetic conversion element integrally therewith; and a load beam for mounting the flexure, wherein the flexure comprises a junction piece protruded from an edge of the flexure for joining the load beam and a main flexure having a cleavage part that is cleaved upon exertion of an external force pulling the flexure in the leading end direction in a state that the junction piece is joined to the load beam.  
         [0012]     According to this structure, in the case where characteristics of the slider in the magnetic head assembly having the main flexure mounted thereon have a problem, the main flexure can be easily removed from the load beam by cleaving the main flexure at the cleavage part. Because it can be cleaved at the cleavage part, the main flexure can be securely and stably removed.  
         [0013]     Moreover, according to the present invention, the sub-flexure may be mounted on the removed load beam, so that the load beam can be reused, promoting effective use of resources.  
         [0014]     A method for manufacturing a magnetic head assembly according to the present invention, the manufacturing method for mounting a flexible flexure, which supports a slider having an electro-magnetic conversion element integrally, on a load beam, the method comprises the steps of detachably joining a main flexure, which has a junction piece for joining the load beam, to the load beam with the junction piece therebetween; inspecting characteristics by floating the electro-magnetic conversion element onto a magnetic disc; when the characteristics do not satisfy a reference as a result of the inspection, removing the main flexure by applying a pulling force to the main flexure so as to detach the junction piece from the load beam; and at least one time joining a sub-flexure, which has a junction piece located at a position different from that of the junction piece of the main flexure, to the load beam, from which the main flexure is detached, at the junction position.  
         [0015]     According to the manufacturing method of the present invention, upon determining the magnetic disc assembly having the main flexure to be defective in the inspection process, the sub-flexure can be mounted on the load beam after the main flexure is removed from the load beam, so that the load beam can be reused, promoting effective use of resources.  
         [0016]     A method for manufacturing a magnetic head assembly according to the present invention, the manufacturing method for mounting a flexible flexure, which has a slider fixed thereto and having an electro-magnetic conversion element integrally, on a load beam, the method also comprises the steps of joining a main flexure, which has a junction piece for joining the load beam, to the load beam with the junction piece therebetween; inspecting characteristics by floating the electromagnetic conversion element onto a magnetic disc; when the characteristics do not satisfy a reference as a result of the inspection, removing the main flexure from the load beam by cleaving the main flexure at a cleavage part disposed in a vicinity of the junction piece; and at least one time joining a sub-flexure, which can be joined at a position different from that of the junction piece, to the load beam, from which the main flexure is removed so as to leave the junction piece.  
         [0017]     According to the manufacturing method of the present invention, upon determining the magnetic disc assembly having the main flexure to be defective in the inspection process, the sub-flexure can be mounted on the load beam after the step of removing the main flexure from the load beam by cleaving the main flexure at the cleavage part, so that the load beam can be reused, promoting effective use of resources. Because it can be cleaved at the cleavage part, the main flexure can be securely and stably removed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a front view of a magnetic-head assembly according to an embodiment of the present invention;  
         [0019]      FIG. 2  is an enlarged front view of a main flexure according to the embodiment;  
         [0020]      FIG. 3  is an enlarged front view showing a vicinity of the end extremity of a load beam according to the embodiment;  
         [0021]      FIG. 4  is an enlarged front view showing a state that the main flexure according to the embodiment is attached to the load beam;  
         [0022]      FIG. 5A  is a front view of a sub-flexure according to the embodiment, and  FIG. 5B  is an enlarged front view showing the load beam after the main flexure is removed from the load beam;  
         [0023]      FIG. 6  is an enlarged front view showing a state that the sub-flexure according to the embodiment is attached to the load beam;  
         [0024]      FIG. 7  is an enlarged front view of a flexure according to another embodiment of the present invention;  
         [0025]      FIG. 8  is a schematic perspective view of an embodiment of test equipment used in a test process according to the present invention; and  
         [0026]      FIG. 9  is a perspective view of a conventional magnetic-head suspension. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     The present invention will be described below with reference to the drawings.  FIG. 1  is a final drawing of a magnetic-head assembly according to an embodiment of the present invention for use in a hard disc drive.  
         [0028]     In the magnetic-head assembly, a slider  11  having an electromagnetic conversion element (a magnetic head)  13  integrated therein is fixed to a flexible main flexure  21 . The main flexure  21  is mounted at the end extremity of the load beam  31  in a state that the slider  11  is elastically suspended on the load beam  31 . The main flexure  21  is a flexible metallic plate like a leaf spring having flexible printed circuit boards (FPCs)  22  and  23  on the surface bonded with adhesive. The flexible printed circuit boards  22  and  23  are separated from each other at terminals  22   a  and  22   b , which are electrically connected to terminals (not shown) of the electro-magnetic conversion element, and extend alongside both-side edges so as to be further pulled out of the rear edges of the main flexure  21  and brought together to become a relay flexible printed circuit board  24 . Terminals of the end of the relay flexible printed circuit board  24  are connected to a control circuit (electronic components) of a hard disc magnetic-disc apparatus to be mounted thereon.  
         [0029]      FIG. 2  is an enlarged view of the main flexure  21  according to the embodiment before being attached to the load beam  31 . The main flexure  21  is provided with a semi-circular junction piece  25  protruded from substantially the central rear end (in the right in  FIG. 2 ).  
         [0030]     On the other hand, the load beam  31  is provided with a support part  32  disposed at the end extremity for supporting the main flexure  21  with a stepped part  31   a  therebetween. The support part  32  is provided with a semi-circular bonding part  33  formed in the vicinity of the stepped part  31   a.    
         [0031]     The junction piece  25  of the main flexure  21  is spot-welded to the bonding part  33  overlapped with the junction piece  25 . Thus the main flexure  21  supports the slider  11  in a non-contact state that the slider  11  is separated from the support part  32  using the bonding part  33  as a fulcrum (a point of action), so that the main flexure  21  functions as a suspension deflecting in directions towards and away from the support part  32  so as to have predetermined deflection characteristics. The flexible printed circuit boards  22  and  23  are bonded to the load beam  31  at portions overlapping with the load beam  31 . The spot welding, as shown in  FIG. 3 , is performed by laser at a cleavage position  25   b  shown by symbol + as a center in a state that the junction piece  25  is abutted and positioned to the bonding part  33 . A tab  34  protruded from the end extremity of the load beam  31  is a member used in allowing running over a slope of a ramp disposed outside the hard magnetic-disc so as to evacuate the slider  11  from the hard magnetic-disc.  
         [0032]     Next, the dynamic characteristic-test process of the magnetic-head assembly will be described.  
         [0033]     First, the magnetic-head assembly having the main flexure  21  attached to the load beam  31  is mounted on an inspection machine such as a spin stand so as to perform predetermined characteristic tests thereon.  
         [0034]     The magnetic-head assembly determined to be non-defective by the dynamic characteristic test results in a product.  
         [0035]      FIG. 8  shows an embodiment of an inspection device for performing the dynamic characteristic test. This is a device for testing characteristics of a magnetic head for recording information on a disc-like magnetic-recording medium (referred to below as a magnetic disc) D and for reproducing the information in the magnetic disc D in a state that the magnetic disc D is rotated and floated. This inspection device  100 , as essentially shown in  FIG. 8 , comprises a magnetic disc  103  rotated by a spindle motor  101 , an arm  105  for fixing the magnetic-head assembly, a motor  107  for precisely moving the arm  105  as an actuator, a movement conversion mechanism  109 , and a cross-roller table  111 . These members are mounted on a base frame (not shown).  
         [0036]     The motor  107  is fixed to a base  115  with a bracket  113  therebetween. The movement conversion mechanism  109  is arranged in a space formed between the base  115  and the bracket  113 . The base  115  is arranged adjustably in position relative to the base frame according to need. The motor  37 , such as a DC motor and a stepping motor, has a rotation precision capable of finely moving the magnetic head (slider) in the diametric direction (X-direction) of the magnetic disc  103  so as to trace a predetermined track.  
         [0037]     The movement conversion mechanism  109  converts the rotational movement of the motor into the linear movement in the X-direction of the arm  105  with a crank mechanism.  
         [0038]     The arm  105  is supported by the cross-roller table  111  slidably in the X-direction. The arm  105  is provided with U-shaped fixing portions  106   a  and  106   b  formed at the end extremity for detachably fixing the magnetic head assembly. To the fixing portions  106   a  and  106   b , two magnetic head assemblies may be detachably held, respectively. According to the embodiment, base plates  35  of the load beams  31  are inserted into the fixing portions  106   a  and  106   b  so as to detachably fix them thereto by screwing screws  121   a  and  121   b  into tapped holes  35   a  ( FIG. 1 ) with the fixing portions  106   a  and  106   b  therebetween, for example. The sliders  11  and  11  are faced to each other at a predetermined interval. End terminals of the relay flexible printed circuit board  24  are connected to input terminals of a reading/writing unit (R/W control unit)  131 .  
         [0039]     In a state that the magnetic head assembly is mounted on the inspection device  100  as described above, the slider  11  is moved to a predetermined track of the magnetic disc  103  by the inspection device  100  and the reading/writing in the magnetic disc  103  by the magnetic head of the slider  11  is controlled by the reading/writing unit  131 . Furthermore, characteristics of the slider  11  are analyzed from signals read by the magnetic head of the slider  11  so as to display at least the analyzed result whether they satisfy predetermined characteristics on a result display  133 . This result may be not only displayed but also be recorded or printed on a recording medium.  
         [0040]     As a result of the inspection by the inspection device, the process when the slider  11  is determined to be defective is as follows.  
         [0041]     An inspector pulls a pulling piece  26  protruded from the end extremity of the main flexure  21  by pinching it with a predetermined jig. Then, the junction piece  25  is decoupled at the cleavage position  25   b , so that only the main flexure  21  is removed from the load beam  31  leaving the junction piece  25 . During the decoupling, the flexible printed circuit boards  22  and  23  are also decoupled in the vicinity of the boundary between the main flexure  21  and the load beam  31 , so that parts  22   b  and  23   b  of the flexible printed circuit boards  22  and  23  and the relay flexible printed circuit board  24  are left in the load beam  31  ( FIG. 5B ).  
         [0042]     In such a manner, according to the embodiment, if the slider  11  on the main flexure  21  is determined to be defective, the main flexure  21  can be simply removed from the load beam  31 .  
         [0043]     Recently, along with a recent progress toward high density in the magnetic recording, there have been advances in the reduction in size of the slider and the reduction in thickness of the flexure. In the conventional magnetic head, the reduction in thickness of the flexure may also reduce the thickness of the relay flexible printed circuit board tending to be liable to deflect. This deflection (rolling) is disadvantageous for handling. Whereas, according to the present invention, by using a material different from that of the main flexure  21 , the relay flexible printed circuit board can be designed to have a thickness suitable for the handling.  
         [0044]     According to the embodiment, since the junction piece  25  may be left in the bonding part  33 , the cleavage position  25   b  may be of any structure as long as it is easily cleavable, such as perforations, kerfs, or constriction.  
         [0045]     Next, a structure of a sub-flexure  212  to be mounted on the load beam  31  ( FIG. 5B ) with the main flexure  21  eliminated will be described with reference to  FIG. 5A . The embodiment is characterized that the sub-flexure  212  is provided in addition to the main flexure  21 ; the main flexure  21  can be easily removed from the load beam  31 ; and the sub-flexure  212  can be mounted on the load beam  31  with the main flexure  21  eliminated.  
         [0046]     The sub-flexure  212  has no equivalent of the junction piece  25  of the main flexure  21 , and furthermore, although the sub-flexure  212  has no equivalents of the terminal parts  22   b  and  23   b  of the flexible printed circuit boards  22  and  23  and the relay flexible printed circuit board  24 , the sub-flexure  212  comprises flexible printed circuit boards  222  and  223  and terminal parts  222   a  and  223   a  respectively corresponding to the flexible printed circuit boards  22  and  23  and the terminal parts  22   b  and  23   b , and terminal parts  222   b  and  223   b  that are overlapped with a conduction wiring pattern of the terminal parts  22   b  and  23   b  when the flexible printed circuit boards  222  and  223  are mounted on the load beam  31 .  
         [0047]     The process when the sub-flexure  212  is mounted on the load beam  31  is as follows.  
         [0048]     In a state that the sub-flexure  212  is located at a predetermined position on the load beam  31 , a bonding position  212   a  shown by symbol + is spot-welded. The bonding position  212   a  is a position different from a bonding position  25   a  of the main flexure  21 , and a corresponding position on the support part  32  of the load beam  31  is also different from the position of the main flexure  21 .  
         [0049]     Then, the terminal parts  222   b  and  223   b  that are respectively overlapped with conduction wiring patterns corresponding to the terminal parts  22   b  and  23   b  are fixed together by a predetermined method such as soldering.  
         [0050]     The sub-flexure  212  mounted in such a manner supports the slider  11  using the bonding point as a fulcrum in a state that the slider  11  is separated from the support part  32  at a predetermined distance so as to support the slider  11  movably in directions towards and away from the support part  32  so as to have predetermined deflection characteristics. The deflection characteristics of the sub-flexure  212  are substantially the same as those of the main flexure  21 .  
         [0051]     On the magnetic-head assembly having the sub-flexure  212  mounted to the load beam  31  in such a manner, a dynamic characteristic test is performed by the above-mentioned inspection device, for example. The magnetic-head assembly determined to be non-defective by the dynamic characteristic test results in a product as a re-workable product.  
         [0052]     As described above, according to the embodiment, as a result of the inspection performed by the dynamic inspection device on the magnetic head assembly having the main flexure  21  fixed to the load beam  31 , if the slider  11  is determined to be defective, since the main flexure  21  can be removed from the load beam  31  and the sub-flexure  212  can be attached to the load beam  31  with the main flexure  21  eliminated, the load beam  31  can be reused as it is.  
         [0053]     According to the embodiment described above, the main flexure  21  may be pulled by pinching the junction piece  25  thereof; alternatively, in order to pull the main flexure  21  without deflection in the longitudinal direction, as shown in  FIG. 7 , the main flexure  21  may be provided with two or more holes  27  formed at edges so as to be fitted by a pin for pulling the main flexure  21 .  
         [0054]     According to the embodiment shown in the drawings, upon determining the main flexure  21  to be defective in the dynamic characteristic test, the main flexure  21  is removed in a state that the junction piece  25  is left in the bonding part  33 ; alternatively, the junction piece  25  may be also removed from the bonding part  33  integrally with the main flexure  21 . In this case, the junction piece  25  of the main flexure  21  is not provided with the cleavage position  25   b.    
         [0055]     Furthermore, in the case where the sub-flexure  212  is attached also having the same structure of the thin plate itself as that of the main flexure, i.e., the structure having a part corresponding to the junction piece  25  of the main flexure  21 , the position of spot welding may be different from the position where the main flexure is welded, or the sub-flexure  212  may also be welded at a spot larger than that of the main flexure  21  overlapping therewith.  
         [0056]     Also, according to the embodiment shown in the drawings, in the case where the main flexure  21  is defective, part of the flexible printed circuit boards  22  and  23  and the relay flexible printed circuit board  24  are left; alternatively the entire flexible printed circuit boards  22 ,  23  and  24  may be removed together.  
         [0057]     As is apparent from the above description, according to the manufacturing method of the magnetic-head assembly of the present invention, if the slider having the flexure or the electro-magnetic conversion element attached to the load beam is determined to be defective as a result of the dynamic inspection, since the main flexure can be removed from the load beam and the sub-flexure can be attached to the load beam with the main flexure eliminated, the load beam can be reused.  
         [0058]     According to the magnetic-head assembly of the present invention, since the main flexure attached to the load beam can be simply removed therefrom and the sub-flexure can be attached to the load beam with the main flexure eliminated, the load beam can be reused.