Patent Publication Number: US-8117628-B2

Title: Apparatus of dynamic anti-vibration for storage device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to an apparatus of dynamic anti-vibration for a storage device, and more particularly, to an apparatus of dynamic anti-vibration for a storage device that actively generates a force to neutralize the vibration. 
     2. Related Art 
     With the increase of data capacity, data density is becoming higher and higher, and the reading device of the storage medium is getting more and more precise. 
     Take the optical drive as an example; the increase of data density has shortened the distance between the optical pickup head and the surface of an optical disk. Vibrations caused either by the unevenness of the optical disk itself during the rotation or by collision from an external force may lead to the shift of the optical pickup head, and thus the optical pickup head cannot be precisely focused on a data track that is predetermined to be read, and may even collide with the optical disk. And in a hard disk drive, the magnetic head of the hard disk drive also has the same problem, that is, it is easily collided because of vibration, and meanwhile, with the increase of the rotation speed of the disk, vibration of the hard disk drive itself further aggravates the problem. 
     Therefore, many anti-vibration designs have been provided. For example, in U.S. Pat. Nos. 6,883,175, 6,834,393, and 6,690,638, damping elements made of rubber materials are placed between the base board of the optical pickup head and the housing of the optical drive so as to absorb kinetic energy to dissipate the vibration. However, the design using damping elements to passively absorb or isolate the vibration is limited by the characteristics of the materials, and thus cannot completely absorb all vibration. In case that amplitude is too large or frequency is too low, the damping elements are not capable of effectively absorbing or isolating the vibrations. Moreover, nowadays, designs for both optical drives and hard disk drives tend to be of higher rotation speeds, and the frequency of eccentric vibration caused by the spindle motor is increased, rendering the effect of vibration absorption or isolation through the damping elements unsatisfactory. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a dynamic anti-vibration apparatus for a storage device, so as to solve the problem of poor performance in conventional passive vibration absorption and isolation devices. 
     To achieve the aforementioned object, the present invention provides a dynamic anti-vibration apparatus for a storage device to support the storage device in a housing, wherein, the storage device can be an optical pickup device of an optical drive or a hard disk drive. The anti-vibration apparatus includes a base board, a plurality of damping elements, at least one actuator and a control unit. 
     The efficacy of the present invention is to actively generate a force through an actuator to neutralize the vibration, which enhances the effect of vibration absorption and isolation and improves overall anti-vibration performance. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a perspective view of a first embodiment of the present invention; 
         FIG. 2  is a partial exploded view of the first embodiment; 
         FIG. 3  is a partial sectional view of the first embodiment; 
         FIG. 4  is a side view of the actuator of the first embodiment; 
         FIG. 5  is a systematic block diagram of the first embodiment; 
         FIG. 6  is a partial sectional view of a second embodiment of the present invention; and 
         FIG. 7  is a perspective view of a third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     To better understand the object, structure, features and functions of the present invention, the embodiments are described below in detail. 
       FIGS. 1 and 2  show a dynamic anti-vibration apparatus for a storage device according to one embodiment of the invention, which is used to support a storage device  50  in a housing  10  and includes a base board  20 , a plurality of damping elements  30 , one or more actuators  40  and a control unit  62  (shown in  FIG. 5 ). 
     The base board  20  is used to hold the storage device  50 , and a plurality of through holes  21  are set in corners of the base board  20  to let a plurality of columns  11  through, and one end of each of the columns  11  is fixed to the inner side of the housing  10 . In this embodiment, the storage device  50  is an optical pickup module or an in-car optical drive, comprising: a spindle motor  51  fixed to the bottom side of the base board  20 , for driving a rotating spindle  512  protruded from the top side of the base board  20 ; an optical pickup head  52  for projecting a laser beam for reading and writing on the read/write surface of an optical disk; a transmission component  53  for causing the optical pickup head  52  to reciprocate within a groove  22  in the base board  20 , wherein the rotating spindle  512  is used to support the optical disk and cause it to rotate, and the transmission component  53  is used to cause the optical pickup head  52  to reciprocate within the groove  22  in the base board  20 , such that the laser beam may be focused on a data track that is predetermined to be read. 
     The plurality of damping elements  30  is made of a rubber material and has damping characteristics. Each of the damping elements  30  has a dowel bore  31  throughout, and has a trench  32  surrounding the periphery on the outer surface thereof. The damping element  30  is placed between the base board  20  and the housing  10 , and each of the columns  11  passes through the dowel bore  31  of the damping element  30 . The trench  32  matches with the through hole  21  of the base board  20 , such that the edge of the through hole  21  is fit in the trench  32 . Thus, the base board  20  and the housing  10  are coupled, and the damping characteristics of the damping elements  30  are used to dissipate the kinetic energy generated by the vibration of the base board  20  to absorb the vibration of the base board  20 . 
     The damping elements  30  passively absorb and dissipate the kinetic energy of the vibration, while the actuator  40  electrically connected to the control unit  62  is driven by the control unit  62 , so as to actively generate a force with the same frequency and the opposite direction to the vibration to directly interfere and thus neutralize the vibration. 
     Referring to  FIGS. 3 and 4  together with  FIG. 2 , the actuator  40  is disposed on the housing  10 , and is connected to a side edge of the base board  20 . Moreover, the storage device  50  further includes the control unit  62  disposed thereon. The actuators  40  are electrically connected to the control unit  62  to be controlled by the control unit  62 . When the base board  20  is vibrated, the actuator  40  is driven by the control unit  62  to generate a force to neutralize the vibration of the base board  20 . 
     In this embodiment, the actuator  40  is a voice coil motor. The voice coil motor includes a pair of yokes  41 , a pair of permanent magnets  42 , a magnetically permeable element  43  and a coil  44 , wherein the yokes  41  are set on the housing  10 , the two permanent magnets  42  are fixed on two sides of the two yokes  41  that face one another, and the magnetically permeable element  43  is also fixed to the housing  10  between the two permanent magnets  42 . The coil  44  is wound about the magnetically permeable element  43 , and is located on two sides of the two permanent magnets  42  that face one another, i.e. the coil  44  is located between the two permanent magnets  42  and the magnetically permeable element  43 , such that the permanent magnets  42 , the magnetically permeable element  43  and the yokes  41  form two pairs of closed loops of magnetic line of force which are perpendicular to the direction of a current in the coil  44 . 
     A connection board  23  is further arranged on the base board  20 . One end of the connection board  23  is fixed to the base board  20 , and the other end forms a dowel bore  231  and extends towards the actuator  40 , and an annular rib  232  is formed on the edge of the dowel bore  231 , wherein the magnetically permeable element  43  may pass through the dowel bore  231 , and then the coil  44  is fixed to the annular rib  232 , such that the coil  44  is combined to the connection board  23  so as to combine the base board  20  and the coil  44 . When a current is supplied to the coil  44 , the amount and direction of the current interact with the permanent magnets  42 , and the amount and direction of the magnetic force generated by the coil  44  can be determined according to Fleming&#39;s left hand rule, and the columns  11  guide the coil  44  to reciprocate along a straight line, such that the force generated by the coil  44  actuates the base board  20 , thus neutralizing the vibration of the base board  20 . 
       FIG. 5  is a systematic block diagram of the first embodiment of the present invention. The storage device  50  further includes a sensor  61  disposed thereon according to the demand. The sensor  61  is electrically connected to the control unit  62 . The amount, phase, and frequency of the force generated by the coil  44  are changed in accordance with the vibration state of the storage device  50 . The sensor  61  is set on the storage device  50  or the base board  20  to measure the vibration state of the storage device  50  or the base board  20 . The sensor  61  can be an acceleration sensor, velocity sensor, a displacement sensor, angular displacement sensor, angular velocity sensor, angular acceleration sensor, force sensor, or torque sensor according to the demand. Then, the measured result is transmitted to a control unit  62 , it is calculated together with the influence caused by the damping elements  30 . Then a current of an appropriate size and direction is sent to the actuator  40 , such that the actuator  40  generates a force with the same frequency, the opposite phase and of an amount that will just neutralize the vibration. Thus, the vibration is further eliminated to reduce the impact of the vibration on the storage device  50 , such that the optical pickup head  52  can be precisely focused on the correct data track, and will not over shift due to the vibration. 
       FIG. 6  shows a dynamic anti-vibration apparatus for a storage device provided in a second embodiment of the present invention, wherein the actuator  70  is a piezoelectric element which has a base  71  and an actuating portion  72 , wherein the base  71  is disposed on the housing  10 , and the actuating portion  72  is disposed on the base  71  and is connected to the connection board  23  of the base board  20 . The actuating portion  72  is made from a piezoelectric material, and deforms when a voltage is received, such that the force is generated to the base board  20  to eliminate the vibration. 
       FIG. 7  shows a dynamic anti-vibration apparatus for a storage device disclosed in a third embodiment of the present invention, wherein a storage device  80  is a hard disk drive fixed on the base board  20 , and damping elements  30  and an actuator  90  are disposed between the base board  20  and the housing  10 , such that the vibration of the base board  20  and the storage device  80  is absorbed with the damping elements  30 , and is simultaneously neutralized by a force actively generated by the actuator  90 . 
     From the above-mentioned embodiments of the present invention, a force is actively generated through an actuator to neutralize the vibration, which enhances the effect of vibration absorption and isolation; therefore, overall anti-vibration performance is achieved. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.