Abstract:
A disk drive suspension has a load beam with a base portion, a spring portion and a rigid portion to carry a flexure and slider in operative association with a disk. The spring portion is normally bendable between the base portion and the rigid portion. Welding of the spring portion to the base portion and the rigid portion tends to raise the temperature of the adjacent parts of the spring portion to temperatures above their annealed temperature and there is a loss of temper and thus spring properties in these adjacent parts. The invention limits the bending of the spring portion to a region between the base and rigid portion adjacent parts by stiffening the spring portion locally in these parts as with an edge rail. The non-railed region of the spring portion remains bendable and is far enough away from welding heat that it retains its temper and spring properties.

Description:
REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application Ser. No. 60/391,823 filed Jun. 26, 2002. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable 
   REFERENCE TO A MICROFICHE APPENDIX 
   Not Applicable 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to disk drive suspensions, and, more particularly, to disk drive multipiece suspensions having a spring portion that is weld-attached to the suspension base and rigid portions. The invention suspensions have the spring portion bend preferentially in a zone removed from the weldment areas to be free of influences of weld-heating. 
   2. Description of the Related Art 
   Multipiece suspensions use a separate metal member as the spring portion. This spring portion is welded to the proximate or base portion of the suspension and to the distal or rigid portion of the suspension. The welding operation may adversely affect the spring properties of the spring portion, particularly since the spring portion has only a small axial extent as suspensions become smaller and smaller. 
   BRIEF SUMMARY OF THE INVENTION 
   It is an object, therefore, of the present invention to provide an improved disk drive suspension. It is a further object to provide a suspension in which the spring portion flexing or bending is limited to a relatively small region that is substantially centered and equidistantly spaced from the proximate and distal sections of the spring portion that are secured by welding to adjacent base and rigid portions of the suspension. It is another object to provide a suspension spring portion that is locally stiffened to have limited bending ability except beyond the locally stiffened zones. It is a further object to provide a disk drive suspension in which the loss of temper in the spring portion sometimes associated with welding the spring portion to adjacent base and rigid portions is avoided in the center of the spring portion, and in which the spring region is substantially restricted to the center of the spring portion. It is a still further object to provide a disk drive suspension spring portion that bends in a limited region well spaced from any areas of the spring portion that may be subjected to weld-heating, the limited region being defined by opposed pairs of rails that are interrupted intermediate their ends at the locus of intended bending. 
   These and other objects of the invention to become apparent hereinafter are realized in a disk drive suspension having along a longitudinal axis a base portion, a rigid portion and a bendable spring portion, the spring portion being extended along the longitudinal axis a given extent and having edge rails that are interrupted at a locus, bending of the spring portion being limited by the edge rails except at their interruption, whereby the locus of the spring portion bending extends longitudinally less than the given extent and is defined by the locus of interruption. 
   In this and like embodiments, typically, the base portion and the spring portion are separately formed and joined together solely by welding, the spring portion edge rails having distal and proximate extents on opposite sides of the locus of interruption, the distal and proximate extents being distal of the welding, the base portion has a distal edge margin, and the spring portion has a proximate edge margin, the distal and proximate edge margins being joined solely by welding, the edge rail extents include a pair of left and right hand proximate edge rail extents and a pair of left and right hand distal edge rail extents, the pairs being laterally opposed, the distal and proximate edge rail extents being longitudinally spaced across the locus of interruption, the spring portion has a proximate section adjacent the proximate edge margin that is free of welding, the proximate edge rail extents extending vertically from the proximate section in proximate section stiffening relation, and the spring portion has a center section distal of and contiguous with the proximate section, the longitudinal extent of the proximate section being such that the heat of welding the spring portion proximate edge margin to the base portion distal edge margin does not substantially reduce the temper hardness of the center section. 
   Additionally, or separately, in this and like embodiments, typically, the rigid portion and the spring portion are separately formed and joined together solely by welding, the spring portion edge rails having distal and proximate extents on opposite sides of the locus of interruption, the distal and proximate extents being distal of the welding, the rigid portion has a proximate edge margin, and the spring portion has a distal edge margin, the proximate and distal edge margins being joined solely by welding, the edge rail extents include a pair of left and right hand proximate edge rail extents and a pair of left and right hand distal edge rail extents, the pairs being laterally opposed, the distal and proximate edge rail extents being longitudinally spaced across the locus of interruption, the spring portion has a distal section adjacent the proximate edge margin that is free of welding, the distal edge rail extents extending vertically from the distal section in distal section stiffening relation, and the spring portion has a center section proximate of and contiguous with the distal section, the longitudinal extent of the distal section being such that the heat of welding the spring portion distal edge margin to the rigid portion distal edge margin does not substantially reduce the temper hardness of the center section. 
   In this and like embodiments, the left and right laterally opposed pairs of rail extents are substantially parallel, the base portion and the spring portion are separately formed and joined together solely by welding, the spring portion edge rails having distal and proximate extents on opposite sides of the locus of interruption, the distal and proximate extents being distal of the welding, the base portion has a distal edge margin, and the spring portion has a proximate edge margin, the distal and proximate edge margins being joined solely by welding, the edge rail extents include a pair of left and right hand proximate edge rail extents and a pair of left and right hand distal edge rail extents, the pairs being laterally opposed, the distal and proximate edge rail extents being longitudinally spaced across the locus of interruption, the spring portion has a proximate section adjacent the proximate edge margin that is free of welding, the proximate edge rail extents extending vertically from the proximate section in proximate section stiffening relation, and the spring portion has a center section distal of and contiguous with the proximate section, the longitudinal extent of the proximate section being such that the heat of welding the spring portion proximate edge margin to the base portion distal edge margin does not substantially reduce the temper hardness of the center section. 
   In a further embodiment, the invention provides a disk drive suspension comprising a load beam having a base portion, a spring portion and a beam portion, the spring portion being normally bendable over a given axial extent between proximate and distal edge margins, the spring portion being locally stiffened between the edge margins to be bendable only over a part of the spring portion axial extent. 
   In this and like embodiments, typically, the spring portion part is intermediate the spring portion distal and proximate edge margins, the spring portion has interrupted right and left hand rails providing the local stiffening. 
   In a further embodiment, the invention provides a disk drive suspension comprising a base portion, a beam portion and a spring portion therebetween, the spring portion having a proximate edge margin welded to the base portion, and a distal edge margin welded to the rigid portion, and a center region between the proximate and distal edge margins, the center region having a proximate section contiguous with the proximate edge margin and subject to loss of temper hardness during welding of the proximate edge margin to the base portion, a distal section contiguous with the distal edge margin and subject to loss of temper hardness during welding of the distal edge margin to the rigid portion, and a center section between the proximate and distal sections that is sufficiently distant from the proximate and distal edge margins to not be subject to loss of temper hardness from welding at the edge margins, the spring portion normally being bendable throughout its center region, the spring portion center region being locally stiffened in its proximate and distal sections to limit spring portion bending to the center section whereby the spring portion bending is localized in the center section and unaffected by edge margin welding. 
   In its method aspects, the invention provides a method of limiting the bendable region of a disk drive suspension spring portion, including supporting the spring portion between a suspension base portion and a suspension rigid portion, and stiffening the spring portion locally to limit the bendable region of the spring portion to the part of the spring portion free of local stiffening. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The invention will be further described in conjunction with the attached drawings in which: 
       FIG. 1  is an exploded, oblique view of the invention suspension; and 
       FIG. 2  is a side elevation view thereof. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The load beam of a disk drive suspension comprises a base portion, a spring portion and a rigid portion arranged to apply a vertical force on the slider as it flies over the disk. The amount of vertical force depends on the vertical stiffness (spring rates) of the load beam and the free state angle as determined by the bend of the load beam. The vertical stiffness also depends on the length of the spring portion of the load beam, the spring portion here being the weaker part of the load beam. Typically, at both ends of spring portion length, the sections adjacent the rigid or base portions are made more rigid than the balance of the spring per se by welding on a mount plate, by forming rails, or by welding a thicker material to it. 
   In general, in a magnetic drive suspension comprising a mount plate, load beam and a flexure, the load beam is welded to the mount plate and the rigid part of the load beam is made by bending the load beam at an angle and/or welding a plate as a stiffener or support plate to it. The rigid portion of the load beam is designed with a view toward having a controlled stiffness, shape and other mechanical parameters to achieve optimum parameters of the suspension. 
   One of the problems with presently available suspensions is a variation in their vertical stiffness property. This property, which is largely governed by the spring portion length (its axial extent parallel with the suspension longitudinal axis), is subject to change as the spring portion is weld-attached to the base portion (which term herein includes the mount plate and other structures at the proximate end of the suspension as well as the base portion per se) and to the rigid portion (which term herein includes the rigid portion per se and any stiffener and support plates that may be added). 
   Vertical stiffness in this respect can vary unpredictably as the weldment diameters and locations vary due to manufacturing tolerances. Further, the suspension resonance frequencies and gains are also varied since they are functions of stiffness as well as of the suspension inertial properties. 
   Spring portion length is generally becoming shorter, particularly with newer, multi-piece designs having a welded support plate piece. It is a serious manufacturing challenge to form the spring in the available short area, but, making the spring length a bit more extended, decreases the resonance frequencies, and weakens the spring portion mechanical properties. 
   The present invention employs short fold up rails to make the spring portion less sensitive to the adjacent welds. A rail on the spring portion that is adjacent or next to the base portion mount plate will minimize the weld diameter effect on the spring portion proximate zone, and a rail on the spring portion that is adjacent or next to the rigid portion support plate will minimize the weld diameter effect on the spring portion distal zone for an improved suspension having improved spring portion properties. 
   In general, the invention strategically placed short rail pairs will provide most of the rigidity near the mount plate, and will define the commencement of the rigid zone very accurately through the possible very tight etching tolerances compared to welding tolerances. Support plate adjacent rails will provide the same benefits at the distal zone of the spring portion, and additionally provide more room for gram forming operations. Further, the presence of the rails at both proximate and distal zones of the spring portion will reduce the effects of the welds, and thus give tighter control of resonance frequencies and gains. This result in turn improves manufacturing yields, as tighter control of resonance is one a key performance parameters. 
   With reference now to  FIGS. 1 and 2  of the drawings in detail, disk drive suspension  10  has a longitudinal axis L, and comprises a load beam  12  having a base portion  14  including a mount plate  16 , a base per se  18  and a base plate  22 . Suspension  10  further comprises a rigid portion  24  including a beam  26  and a support plate  28 . Suspension  10  further includes a bendable spring portion  32 . Spring portion  32  is extended along the longitudinal axis L a given extent E and has local stiffening through thickening, folding or otherwise increasing the amount or nature of the material in the area of local stiffening, and preferably, as shown, by providing edge rails  42 ,  44 ,  46 ,  48  arranged by virtue of interruption  50  at locus  52  into a proximate pair  54 , and a distal pair  56 . In accordance with the invention the edge rails  42 – 48  locally stiffen the spring portion  32  on either side of locus  52  to allow bending of the spring portion substantially solely at the locus where the spring portion is free of stiffening. Thus, bending of the spring portion  32  is limited by the edge rails  42 – 48  except at their interruption  50 . Since the spring portion  32  length, extent E, is not changed, just the bendable region  58  of the spring portion, it will be noted that the locus  62  of spring portion bending extends longitudinally less than the given extent E and is defined by the locus  52  of interruption  50 . 
   In the preferred embodiment shown, the suspension  10  includes a unitary elongated member  72  shaped distally into a forward segment  74  that forms the beam  26 , a proximate segment  76  that forms the base  18  and a spring segment  78  that is the spring portion  32 . Base portion mounting plate  16  and base plate  22  are separately formed from the spring segment/spring portion  78 / 32  and are joined together preferably solely by welding at sites  82 . 
   The spring portion  32  edge rails  42 – 48  include the pair  56  of distal extents  42 ,  44  and the pair  54  of proximate extents  46 ,  48 , the pairs being located to be laterally opposed between pair members and longitudinally opposed across, or on opposite sides of, the interruption locus  52 . Distal and proximate edge pairs  56 ,  54  are located distal of the welding sites  82 . 
   The base portion  14  has a distal edge margin  84 , and the spring portion  32  has a proximate edge margin  86 . These distal and proximate edge margins  84 ,  86  are preferably joined solely by welding, as at sites  82 . The edge rail extents  42 – 48  include the pair  54  of left and right hand proximate edge rail extents  46 ,  48  and the pair  56  of left and right hand distal edge rail extents  42 ,  44 . 
   Spring portion  32  has a proximate section  88  adjacent the proximate edge margin  86  and that is free of welding. The proximate edge rail extents  46 ,  48  extend vertically, e.g. at 30 to 90 degrees from the planar surface  92  of proximate section  88  in proximate section stiffening relation. 
   The spring portion  32  further has a center section  94  distal of and contiguous with the proximate section  88 . The longitudinal extent LEP of the proximate section  88  is such that the heat of welding the spring portion proximate edge margin  86  to the base portion distal edge margin  84 , e.g. at sites  82 , does not substantially reduce the temper hardness of the center section  94 . 
   The spring portion  32  further is weld-attached to the rigid portion support plate  28  where the support plate is separately formed from the spring portion, and typically joined solely by welding. The rigid portion support plate  28  has a proximate edge margin  96 ; spring portion having a distal edge margin  98 . The plate  28  proximate edge margin  96  and the spring portion edge margin  98  are typically joined solely by welding e.g. at sites  83 . The edge rail extents  42 – 48  are as just described and extend in the spring portion distal section  102  that is adjacent and inward of the spring portion distal edge margin  98  and typically free of welding. The distal edge rail extents  42 ,  44  extend vertically, e.g. at 30 to 90 degrees from the planar surface  95  of distal section  102  in distal section stiffening relation. Spring portion center section  94  is proximate of and contiguous with the distal section  102 . The longitudinal extent LED of the distal section  102  is such that the heat of welding the spring portion distal edge margin  98  to the rigid portion proximate edge margin  96  does not substantially reduce the temper hardness of the center section  94 . 
   The left and right rail extents  42 ,  46  and  44 ,  48  that are laterally opposed are preferably substantially parallel, that is within 30 degrees of parallel. 
   In summary, the invention apparatus comprises disk drive suspension  10  with a load beam  12  having a base portion  14 , a spring portion  32  and a rigid or beam portion  24 . Spring portion  32  is normally bendable over a given axial extent E between spring portion proximate and base portion distal edge margins  86 ,  84 , but the spring portion is locally stiffened between its proximate and distal edge margins  86 ,  88  to be bendable only over a part of the spring portion axial extent E defined by bendable region  58 . The spring portion axial extent E is intermediate the spring portion distal and proximate edge margins  98 ,  86  and the spring portion has interrupted right and left hand rails  42 – 48  providing the local stiffening. 
   In further detail, the invention disk drive suspension  10  comprising the base portion  14 , a rigid or beam portion  24  and a spring portion  32  therebetween. The spring portion  32  has a proximate edge margin  86  welded to the base portion  14 , a distal edge margin  98  welded to the rigid portion  24 , and a center region or section  94  between the proximate and distal edge margins. The center region  94  has a proximate section  88  contiguous with the base portion distal proximate edge margin  84  and subject to loss of temper hardness during welding of the spring portion proximate edge margin  86  to the base portion distal edge margin. Center region  94  further has a distal section  102  contiguous with the spring portion distal edge margin  98  and subject to loss of temper hardness during welding of the distal edge margin to the rigid portion  24 , and a center section  94  between the proximate and distal sections that is sufficiently distant from the spring portion proximate and distal edge margins to not be subject to loss of temper hardness from welding at the edge margins. The spring portion  32  is normally bendable throughout its center region  94 , but the spring portion center region is locally stiffened in its proximate and distal sections  88 ,  102  to limit spring portion bending to the center section, whereby the spring portion bending is localized in the center section and unaffected by edge margin welding. 
   The invention method for limiting the bendable region of a disk drive suspension spring portion  32  includes supporting the spring portion between a suspension base portion  14  and a suspension rigid portion  24 , and stiffening the spring portion locally to limit the bendable region of the spring portion to the part  58  of the spring portion free of local stiffening. 
   The invention thus provides an improved disk drive suspension in which the spring portion flexing or bending is limited to a relatively small region that is substantially centered and equidistantly spaced from the proximate and distal sections of the spring portion that are secured by welding to adjacent base and rigid portions of the suspension by having the spring portion locally stiffened to have limited bending ability except beyond the locally stiffened zones. In the improved disk drive suspension the loss of temper in the spring portion sometimes associated with welding the spring portion to adjacent base and rigid portions is avoided in the center of the spring portion, as the spring region is substantially restricted to the center of the spring portion, and the spring portion bends in a limited region well spaced from any areas of the spring portion that may be subjected to weld-heating, the limited region being defined by opposed pairs of rails that are interrupted intermediate their ends at the locus of intended bending. 
   The foregoing objects are thus met.