Resonant frequency separation for an actuator assembly of a disc drive

Abstract

An actuator assembly is provided that includes a body portion, a first actuator arm assembly, a second actuator arm assembly, a first flexure assembly, and a second flexure assembly. Each of the first and second actuator arm assemblies projects from the body portion and has a distal end with different respective first and second mechanical configurations. Each of the flexure assemblies is respectively mounted to the distal ends of the first and second actuator arm assemblies. The first and second mechanical configurations are selected to provide the first and second flexure assemblies with different mechanical resonance characteristics. In a preferred embodiment, the second actuator arm assembly includes an actuator arm and a spacer disposed between the actuator arm and the second flexure assembly. The spacer has a stiffness different from the stiffness of the actuator arm.

What is claimed is:  
     
         1 . An actuator assembly, comprising: 
 a body portion;    first and second actuator arm assemblies which project from the body portion and which have distal ends with different respective first and second mechanical configurations; and    first and second flexure assemblies respectively mounted to the distal ends of the first and second actuator arm assemblies, wherein the first and second mechanical configurations are selected to provide the first and second flexure assemblies with different mechanical resonance characteristics.    
     
     
         2 . The actuator assembly of  claim 1 , wherein the second actuator arm assembly comprises an actuator arm and a spacer disposed between the actuator arm and the second flexure assembly.  
     
     
         3 . The actuator assembly of  claim 2  wherein the spacer has a stiffness different from a stiffness of the actuator arm.  
     
     
         4 . The actuator assembly of  claim 1 , wherein the first actuator arm assembly comprises a first actuator arm having a first mounting area to which the first flexure assembly is affixed, wherein the second actuator arm assembly comprises a second actuator arm having a second mounting area to which the second flexure assembly is affixed, and wherein the second mounting area is smaller than the first mounting area.  
     
     
         5 . The actuator assembly of  claim 4 , wherein a notch is formed in the second actuator arm to define the second mounting area.  
     
     
         6 . The actuator assembly of  claim 1 , wherein the first and second flexure assemblies are nominally identical.  
     
     
         7 . The actuator assembly of  claim 1 , wherein the first and second flexure assemblies respectively comprise first and second data transducing heads in a disc drive.  
     
     
         8 . The actuator assembly of  claim 1 , wherein swage interconnections are used to affix the first flexure assembly to the first actuator arm assembly and to affix the second flexure assembly to the second actuator arm assembly.  
     
     
         9 . The actuator assembly of  claim 1 , wherein adhesive is used to affix the first flexure assembly to the first actuator arm assembly and to affix the second flexure assembly to the second actuator arm assembly.  
     
     
         10 . The actuator assembly of  claim 1 , wherein the body portion is rotatable about an actuator axis which extends substantially normal to a direction along which the first and second actuator arm assemblies extend.  
     
     
         11 . The actuator assembly of  claim 2  further comprising a third flexure assembly mounted to the distal end of the second actuator arm, wherein the second flexure is mounted to a top side of the second actuator arm and the third flexure is mounted to a bottom side of the second actuator arm.  
     
     
         12 . A disc drive, comprising: 
 first and second flexure assemblies;    first means for supporting the first flexure assembly; and    second means for supporting the second flexure assembly, wherein the second means provides mechanical response characteristics different from mechanical response characteristics provided to by the first means.    
     
     
         13 . The disc drive of  claim 12 , wherein the first means comprises a first actuator arm assembly having a distal end with a first mechanical configuration and wherein the second means comprises a second actuator arm assembly having a distal end with a second mechanical configuration different from the first mechanical configuration.  
     
     
         14 . The disc drive of  claim 13 , wherein the second actuator arm assembly comprises an actuator arm and a spacer disposed between the actuator arm and the second flexure assembly.  
     
     
         15 . The disc drive of  claim 14  wherein the spacer has a stiffness different from a stiffness of the actuator arm.  
     
     
         16 . The disc drive of  claim 13 , wherein the first actuator arm assembly comprises a first actuator arm having a first mounting area to which the first flexure assembly is affixed, wherein the second actuator arm assembly comprises a second actuator arm having a second mounting area to which the second flexure assembly is affixed, and wherein the second mounting area is smaller than the first mounting area.  
     
     
         17 . The disc drive of  claim 12 , wherein the first and second flexure assemblies are nominally identical.  
     
     
         18 . The disc drive of  claim 12  wherein the first flexure assembly is attached to a top side of an actuator arm and the second flexure assembly is attached to a bottom side of the actuator arm.  
     
     
         19 . A method for forming an actuator, comprising: 
 providing first and second actuator arm assemblies having different, respective first and second mechanical configurations;    providing first and second flexure assemblies;    affixing the first flexure assembly to the first actuator arm assembly; and    affixing the second flexure assembly to the second actuator arm assembly, wherein the second mechanical configuration results in the second flexure assembly having different mechanical response characteristics as compared to mechanical response characteristics of the first flexure assembly.    
     
     
         20 . The method of  claim 19 , wherein the providing first and second flexure assemblies step comprises providing nominally identical first and second flexure assemblies.  
     
     
         21 . The method of  claim 19 , wherein the providing first and second actuator arm assemblies step comprises providing the second actuator arm assembly with a spacer that is disposed between the second flexure assembly and a second actuator arm of the second actuator arm assembly during the affixing the second flexure assembly step.  
     
     
         22 . The method of  claim 19 , wherein the providing first and second actuator arm assemblies step comprises forming a notch in a second actuator arm of the second actuator arm assembly to reduce a flexure mounting area of the second actuator arm as compared to a flexure mounting area of a first actuator arm of the first actuator arm assembly.