Acoustic isolator for a disc drive assembly

Abstract

An improved acoustic isolation apparatus for reducing the total acoustic noise of a disc drive assembly and the like, comprising at least one acoustic isolator having a selectively reduced thickness acoustic compliance area disposed between an excitation source and a support member to impede coupling of vibrations from the excitation source and the structure member to prevent the vibrations from inducing harmonic vibrations in the support member, thus reducing the total acoustic noise.

What is claimed is:  
     
         1 . An improved acoustic isolation apparatus for reducing the acoustic noise produced by a system having at least one excitation source disposed so as to impart vibrations to a structure member coupled thereto, the acoustic isolation apparatus comprising: 
 at least one acoustic isolator providing determined compliance of the structure member in a selected area of compliance disposed to impede coupling of the vibrations of the excitation source and the structure member.    
     
     
         2 . The improved acoustic isolation apparatus of    claim 1    wherein the excitation source is attached to the structure member at a contact point, and wherein the acoustic isolator comprises an acoustic compliance area on the structure member disposed to provide the increased compliance in near proximity to the contact point.  
     
     
         3 . The improved acoustic isolation apparatus of    claim 2    wherein the acoustic isolator is integrally formed with the structure member.  
     
     
         4 . The improved acoustic isolation apparatus of    claim 3    wherein the acoustic isolator further comprises damping means supported by the acoustic compliance area for damping acoustic coupling in cooperation with the compliance of the acoustic compliance area.  
     
     
         5 . In a disc drive having a housing assembly supporting an excitation source such as an internal motor or the like attached to at least one housing wall such that vibrations of the excitation source are coupled to the housing causing portions of the housing assembly to vibrate in sympathy with the vibrations to cause acoustic noise, an improved acoustic isolation apparatus comprising: 
 acoustic isolator means supported by the housing assembly providing determined compliance in a selected axis of compliance while maintaining rigidity of the housing assembly so that sympathetic coupling of vibration from the excitation source with the housing assembly is substantially impeded.    
     
     
         6 . The improved acoustic isolation apparatus of    claim 5    wherein the acoustic isolator means comprises: 
 at least one acoustic isolator supported by the housing assembly and disposed to provide increased compliance at an acoustic compliance area.  
 
     
     
         7 . The improved acoustic isolation apparatus of    claim 6    wherein the at least one of the acoustic isolators comprises: 
 damping means supported on the acoustic compliance area for damping a portion of the vibration energy from the excitation source imparted to the housing wall.  
 
     
     
         8 . The improved acoustic isolation apparatus of    claim 6    wherein a portion of the acoustic isolator is integrally formed with the housing wall.  
     
     
         9 . The improved acoustic isolation apparatus of    claim 7    wherein a portion of the acoustic isolator is integrally formed with the housing wall.  
     
     
         10 . An improved acoustic isolation apparatus for a disc drive, the disc drive having an external housing with a lower surface and a top surface, the disc drive including at least one motor with a stationary shaft secured to and between the lower and top surfaces of the housing, whereby vibration of the motor is coupled to the housing at the attachment points to cause the surfaces to vibrate to create acoustic noise, the improved acoustic isolation apparatus comprising: 
 at least one high compliance area located on one of the surfaces of the housing, the high compliance area having a thickness less than the thickness of the remainder of the surface, the high compliance area being selected to minimize the passage of the motor vibrations from the second attachment point to the remainder of the surface so that overall acoustic noise is reduced thereby.  
 
     
     
         11 . The improved acoustic isolation apparatus of    claim 10    further comprising a damping pad supported on at least one of the high compliance areas.  
     
     
         12 . The improved acoustic isolation apparatus of    claim 10    further comprising: 
 a second high compliance area located on one of the surfaces, the second high compliance area having a reduced thickness and disposed in close proximity to the periphery of the surface and extending along substantially the entire periphery of the surface.  
 
     
     
         13 . The improved acoustic isolation apparatus of    claim 12    further comprising a damping pad supported on the second high compliance area.  
     
     
         14 . A method for reducing acoustic noise emission from a disc drive assembly or the like having a housing assembly supporting an excitation source such as an internal motor or the like attached to at least one housing wall such that vibrations of the excitation source are coupled to the housing to cause portions of the housing assembly to vibrate to emit acoustic noise, the method comprising the steps of: 
 determining the frequencies of acoustic noise to be reduced for the disc drive assembly; and    reducing the thickness of the housing wall to form at least one acoustic compliance area of increased compliance in a selected axis of compliance so that the selected frequencies of acoustic noise are attenuated a desired amount.    
     
     
         15 . The method for reducing acoustic noise emission of    claim 14    wherein at least one acoustic compliance area is disposed in near proximity to the point of contact between the excitation source and the housing wall.  
     
     
         16 . The method for reducing the acoustic noise emission of    claim 14    further comprising the step of: 
 placing damping material on at least one of the acoustic compliance areas.  
 
     
     
         17 . The method for reducing the acoustic noise emission of    claim 14    wherein the excitation source imparts vibrations to the housing wall along a substantially vertical axis, wherein the selected axis of compliance is vertical, and wherein at least one acoustic compliance area is in near proximity to the point of contact between the excitation source and the housing wall.  
     
     
         18 . A method for attenuating undesirable acoustic noise from a disc drive assembly having a housing assembly containing an excitation source such as a motor having a vertically extending shaft attached to at least one wall of the housing assembly at a contact point, the method comprising the step of: 
 reducing the wall thickness of a portion of the wall to provide an acoustic compliance area at the contact point while maintaining the rigidity of the housing assembly as necessary to support the vertically extending shaft, the acoustic compliance area having an increased compliance in the vertical axis thereof sufficient to attenuate selected frequencies of acoustic noise.    
     
     
         19 . The method for attenuating undesirable acoustic noise of    claim 18    further comprising: 
 placing a damping pad on the acoustic compliance area to provide further acoustic noise attenuation as desired.