KR20030080098A - Parallel spring design for acoustic damping of a disc drive - Google Patents

Abstract

The present invention relates to a beam buffer 140 for mitigating noise generated by an actuator 110 of a disk drive 100. Beam buffer 140 is compressed between a portion of housings 102 and 104 of disk drive 100 and actuator motor 126. Beam buffer 140 includes a substantially flat platform 148 secured to selected ones of housings 102 and 104 and upper or lower poles 134 and 154 of actuator motor 126. The multiple flex beams 150 extend from the platform 148 at an angle selected to resiliently locate the housing relative to the actuator motor 126 and with the remaining one of the housing 102, 104 and the upper or lower poles 134, 154. Contact. Beam buffer 140 is formed from a sheet of ductile metal stamped to form flex beam 150 with platform 148 after flex beam 150 is bent at a desired angle.

Description

PARALLEL SPRING DESIGN FOR ACOUSTIC DAMPING OF A DISC DRIVE}

Disk drives are commonly used in many computer environments to store large amounts of data in a form readily available to a user. Typically, a disk drive has one or more data storage surfaces that are rotated by a spindle motor at a constant high speed. Each disc has a data storage surface divided into a series of concentric data tracks with radial spacing over a band having an inner diameter and an outer diameter. Data is stored in a data transformer in the form of flux transitions. This flux variation is made by one or more read / write heads.

Each read / write head includes an interactive element, such as a magnetic transducer. The transducer senses magnetic variation on the selected data track for writing data to or reading data stored in the data track. Each read / write head is mounted to a rotary actuator arm and positioned above the data track selected by the actuator arm for writing data to the data track or for reading data stored in the data track. Each read / write head includes a slider assembly having an air bearing surface that causes the head to fly over the disk in response to the air flow generated by the disk rotation. The read / write head and the disk are separated by a predetermined gap.

In general use, a plurality of centrally opened disks and spacer rings are alternately stacked on a spindle motor hub. The hub defining the core of the stack also serves to align the disks and spacers around a common axis. The disk, spacer ring and spindle motor hub collectively form a disk pack assembly. A read / write head mounted in a complementary stack of actuator arms to form part of the actuator assembly accesses the surface of the stacked disks. The actuator assembly includes features for transferring electrical signals from the read / write heads to the flex circuits, which transfer the electrical signals to a flex circuit connector mounted to the base deck of the disk drive.

When the disk drive is not used, the read / write head is parked at a position separate from the data storage surface of the disk. In general, a landing zone is provided on each disk surface where the read / write head is positioned before the rotational speed of the spindle disk is reduced below the critical speed required to maintain the air bearing. In general, the landing zone is located near the inner diameter of the disc.

The actuator assembly generally has an actuator body pivoting around a pivot assembly disposed in an intermediate position of the actuator assembly. The voice coil motor is located at the nearest end of the actuator assembly. Located at the closest end of the actuator assembly, the far end of the actuator assembly supporting the read / write head can move across the disk face.

The coil of the voice coil motor carries current. The current flowing through the coil forms an electric field. The coil is located in a magnetic field between the upper pole and the lower pole of the voice coil motor. The electric field of the coil interacts with the magnetic fields formed by the upper and lower poles to cause the actuator assembly to pivot around the pivot assembly.

The pivoting action of the actuator assembly generates reaction forces in the fixed upper and lower poles, causing the upper and lower poles to vibrate. Since the upper and lower poles are attached to the base deck, vibrations of the upper and lower poles are transmitted throughout the disk drive, in particular to the top cover. Vibration of the top cover causes the top cover to make noise with respect to the surrounding environment.

Many attempts have been made to solve the undesirable vibration problem of voice coil motors. For example, US Pat. No. 5,999,374 to Kim'374, issued to Kim, discloses the use of three elastic threaded shock absorbers inserted in the bore of the upper yoke (upper pole). The tops of the three elastic buffers are pressed against the inner surface of the top cover to suppress the movement of the top cover.

U. S. Patent No. 6,175, 469 (Ahmad'469) to Ahmad et al. Discloses the use of an elastomeric member bonded to a magnetically permeable liner to form a cushioning member. The shock absorbing member is attached to the top cover of the disc and pressed between the top cover and the top pole of the voice coil motor.

Kim'374's shock absorber and Ahmad'469's shock absorber operate to reduce the vibration of the upper cover, but the noise generated by the upper cover is further reduced by dissipating the vibration energy generated by the voice coil motor and transmitted to the upper cover. There remains a need for an apparatus to effectively reduce.

TECHNICAL FIELD The present invention relates to disk drive data storage devices and, more particularly, to shock absorbers for mitigating noise generated by disk drives.

1 is a plan view partially cut away of a disk drive constructed in accordance with a preferred embodiment of the present invention.

FIG. 2 is a plan view illustrating the inside of the top cover and the beam buffer of the disk drive of FIG. 1.

3 is an isometric view of the beam buffer of FIG. 2.

4 is a cross-sectional view taken along the 4-4 portion shown in FIG.

5 is a partial cross-sectional view of the beam buffer with the voice coil motor of the disk drive.

6 is a partial cross-sectional view of a beam buffer according to another embodiment of the present invention.

7 is a partial cross-sectional view of a beam buffer according to another embodiment of the present invention.

According to a preferred embodiment of the present invention, a beam buffer for the voice coil motor (VCM) of the disk drive is provided to reduce the noise generated by the disk drive. The beam buffer reduces noise by dissipating the vibration energy of the disk drive.

The disk drive includes a VCM having a top cover and an upper magnetic pole. The VCM generates vibration energy of the disc drive by the force acting on the upper pole and the lower pole in response to the electrical force generated by the VCM to move the actuator assembly. The beam buffer is attached to the top cover of the disc drive and supported above the top pole. The beam buffer includes a series of flex beams comprising a substantially flat platform and engaging the top pole to elastically position the top cover away from the top pole and away from the top pole.

Various features and advantages of the features of the present invention will be apparent from the following description and the accompanying drawings.

Referring now to the general drawings, in particular FIG. 1, a plan view of a disk drive 100 constructed in accordance with a preferred embodiment of the present invention is shown. Disk drive 100 includes a base deck 102 on which various disk drive components are mounted. The disk drive also has a cover 104 that forms the housing of the disk drive 100 together with the base deck 102 and the gasket 105.

Top cover 104 is shown in a partially cut away manner to represent the selected components that are important. Various components of the disk drive 100 are well known to those skilled in the art and are not included in the following description because they are unnecessary to the description of the present invention.

Spindle motor 106 is mounted to base deck 102, and one or more disks 108 are in turn mounted to spindle motor 106. The clamp ring 110 fixes the spindle motor 106 for constant high speed rotation. Actuator assembly 112 is located immediately adjacent to disk 108. The actuator assembly 112 pivots around the pivot bearing assembly 114 in a plane parallel to the disk 108. The actuator assembly includes an E-block 115 supported by the pivot bearing assembly 114. E-block 115 has an actuator arm 116 that supports rod arm assembly 118. The load arm assembly 118 in turn supports the read / write head 120 and each read / write head 120 is adjacent to the surface of one of the disks 108. The read / write head 120 is maintained in a spatial relationship of data reading or data writing using a conventional slider assembly (not shown) that supports the read / write head 120.

Each disc 108 has a data storage location having a data recording surface 122 divided into concentric data tracks (not shown) and the read / write head 120 reads data from the data track or writes data to the data track. It is located adjacent to the data track to record it. The data recording surface 122 is a circular, textured landing zone 124 near the inner diameter of one of the discs 108 where the read / write head 120 is stationary when the disc drive 100 is not used. Has

E-block 115 is positioned by voice coil motor (VCM) 126. The E-block has a coil yoke 128 attached to the E-block 115 at the nearest end of the actuator assembly. Coil yoke 128 supports coil 130. The coil 130 is in a magnetic field formed by the magnet assembly 132. The magnet assembly 132 in turn comprises a pair of steel plates (upper pole 134 and lower pole 136) that support upper and lower permanent magnets (only upper pole 134 is shown in FIG. 1).

Coil 130 is located between the upper and lower magnets. As current passes through the coil 130, an electromagnetic field is created that interacts with the magnetic field formed by the magnet assembly 132 to allow the coil 130 to move relative to the magnet assembly 132. The movement of the coil 130 pivots the actuator assembly 112 around the pivot bearing assembly 114 to position the read / write head in the desired position relative to the disk 108. The flex circuit 138 provides an essential electrically conductive path between the actuator assembly 132 and the disk drive printed circuit board (not shown). The disc drive printed circuit board is mounted to the bottom side of the base tech 102. The disk drive printed circuit board provides a disk drive read / write circuit for controlling the operation of the read / write head 120. The disk drive printed circuit board also provides other interface and control circuitry for the disk drive 100.

1 shows beam buffer 140 (in dashed lines). As described below, the beam buffer 140 is located between the top cover 104 and the top pole 134 to reduce noise generated by the disc drive 100.

2 is a plan view of the inner surface of the top cover 104 for illustrating the beam buffer 140 in more detail. For reference, features of the top cover 104 shown in FIG. 2 include an actuator assembly contact point 142, a spindle motor contact point 144, and a stacked cushioning structure 146 adjacent the disk 108.

Beam buffer 140 is attached to the inner surface of top cover 104 using an attachment layer or other suitable fixing method. Beam buffer 140 includes a planar base or platform 148 on which a plurality of flex beams 150 extend at an angle. When the top cover 104 is attached to the base deck 102, the flex beam 150 comes into contact with the top pole 134 and resiliently positions the top cover 104 away from the top pole 134. This position is elastic because the flex beam 150 behaves like a spring in this configuration. As such, the flex beam 150 dissipates the vibration energy transmitted to the flex beam 150 through the upper pole 134 but firmly couples the upper cover 104 to the upper pole 134. Each flex beam 150 of the series of flex beams 150 has a desirable spacing along the chord (middle line) of the beam buffer 140 as shown.

3 and 4 show the beam buffer 140 in more detail. 3 is an isometric view and FIG. 4 is a cross-sectional view taken along the line 4-4 in FIG. Beam buffer 140 is formed from a planar sheet of material, such as stainless steel or other ductile metal. Sheets of such materials are stamped and cut to provide the desired structure. The flex beam 150 is cut and bent upward at the desired angle to create an opening 152 corresponding to the platform 148. The flex beam 150 may maintain substantially the same shape as the opening 152, or may be trimmed from around the flex beam 150 such that a small amount of material is smaller than the corresponding opening 152. have.

5 shows a cross-sectional view of the beam damper 140 with the VCM 126. The magnet assembly 132 of the VCM 126 includes an upper pole 134 and a lower pole 154 and upper and lower permanent magnets 156 and 158. Coil 130 is shown positioned between magnets 156 and 158. The tip 160 of each flex beam 150 is pressed against and contacts the top surface of the upper pole 134. Thus, the vibration of the magnet assembly 132 caused by the rapid movement of the coil 130 is mitigated by the compression of the flex beam 150 between the top cover 104 and the top pole 134. The desired amount of compression and resulting cushioning is achieved by appropriate selection of the flex beam 150 size, the starting angle at which the flex beam 150 is formed with the platform 148, and the elastic modulus of the material.

6 shows a cross sectional view of a beam buffer 140 constructed in accordance with another embodiment of the present invention. In particular, the beam buffer 140 includes a flex beam 162 having a semicircular side as shown. Each flex beam 162 includes a curved engagement surface 164 in pressure contact with the upper pole such that the tip 166 does not contact the upper pole 134. The advantage of this configuration is to reduce such things as particle generation due to scraping contact of the beam buffer 140 and the upper pole 134.

7 shows a cross sectional view of a beam buffer 140 constructed in accordance with another embodiment of the present invention. The beam buffer 140 of FIG. 7 shows attached to the upper pawl 134 instead of the top cover 104. The beam buffer of FIG. 7 has a substantially linear flex beam 168 as shown in the embodiment of FIGS. 1-5 but with the addition of a vibration-absorbing material 170 such as rubber. The material 170 is provided at the tip 172 of each flex beam 168 and not only improves the cushioning properties of the beam buffer 140 but also functions to reduce particle generation. The vibration-absorbing material can be a coated or separate piece of material.

For all embodiments of the present invention described above with respect to FIGS. 1-7, the beam buffer 140 resiliently positions the top cover 104 away from the top pole 134 by reducing excitation of the top cover 104. This provides a more robust assembly for energy dissipation. The number of flex beams shown in FIGS. 1-7 is exemplary only and does not limit the scope of the present invention.

Beam buffers with different numbers of flex beams provide different cushioning properties for the top cover 104. Thus, the specific number and configuration of the flex beams is preferably selected according to the conditions of use given.

In general, the larger the number of flex beams, the greater the vibration energy dissipated by the flex beam and the more the vibration energy tends to be distributed over a larger area. Therefore, it is desirable to use more flex beams for beam dampers that manufacturing limits allow. Do. Moreover, using more flex beams can somewhat change the rigidity of each flex beam without significantly affecting the overall energy dissipation by the beam buffer.

Beam buffer 140 has several advantages over the prior art. Beam buffer 140 is easily manufactured and installed, which is important in large volume disk drive manufacturing environments. Operation of the flex beams 150, 162, 168, such as plate springs, provides an improved coupling between the top cover 104 and the top pawl 134 as compared to sandwich type compressible materials such as those disclosed by Kim'374 and Ahmad'469. . The flex beam improves the relaxation of the vibration in a direction parallel to the direction of movement of the coil 130, and unlike the compressed material, the flex beam is released after time and does not weaken the elastic force. Desired cushioning properties can be readily obtained through appropriate selection of the number and configuration of the flex beams.

Although the beam buffer 140 is located between the upper cover 104 and the upper pole 134 in this embodiment, this configuration is exemplary only and does not necessarily limit the present invention as hereinafter claimed. Thus, it may be easily contemplated that the beam buffer 140 be positioned between the base deck 102 and the lower pawl 154 as needed.

The present invention (illustrated herein and claimed below) relates to a beam buffer 140 for a VCM 126 of a disk drive to reduce noise generated by the disk drive 100. The beam buffer reduces noise by dissipating the vibration energy of the disk drive. The disk drive 100 includes a VCM 126 having a top cover 104 and a magnetic top pole 134. The VCM induces vibrational energy in the disc drive by forces acting on the upper pole and the lower pole in response to the electrical forces acting to actuate the actuator assembly 112 into a pivot. The beam buffer is attached to the top cover to align with the top pole when the top cover is attached to the base deck 102. The beam buffer includes (a) a substantially flat platform 148; A plurality of flex beams 150, 162, 168 extending from the platform and contacting the top poles to resiliently position the top cover away from the top poles of the VCM.

In the following claims, it is understood that the recited function performed by the first means is performed by the disclosed beam buffer 140 with the platform 148 fixed to the pawl 134 or to the housing member (upper cover 104). Can be. Multiple flex beams 150, 162, 168 extend from the platform at a desired angle and contact the remaining portion of housing 10 and pawl 134. The beam buffer 140 is formed of a ductile metal so that the flex beam can operate substantially like a leaf spring. Thus, layers of compressible foam rubber or other elastic shock absorbers, such as those disclosed in Kim'374 and Ahmad'469, are not included in the claims, and the formation of structures identical to the claims is excluded.

While many features and advantages of the various embodiments of the present invention have been described, along with the functions and detailed structures of various embodiments of the present invention, these descriptions are illustrative only and to the extent indicated by the broad meaning of the terms set forth in the claims below With regard to partial arrangements and structures within the principles of the invention, various changes may be made in detail. For example, certain elements may vary depending on the particular use of the beam buffer, but may maintain the same functionality without departing from the scope and spirit of the present invention.

In addition, although the embodiments disclosed herein relate to beam buffers for disk drives, it will be apparent to those skilled in the art that beam buffers may be used in other devices in which noise generation is a problem without departing from the spirit and scope of the present invention.

Claims (10)

A beam buffer for a voice coil motor of a disk drive, wherein the disk drive has a top cover and the voice coil motor has a magnetically permeable top pole, and the beam buffer is located between the top pole and the top cover. , (a) a substantially flat platform; And (b) a beam buffer comprising a plurality of flex beams extending from the platform and contacting the top pawl such that the top cover is elastically positioned away from the top surface. The beam buffer of claim 1, wherein the material of the beam buffer is a ductile metal. The beam buffer of claim 1, wherein an end of each flex beam is covered by a vibration-absorbing material. The beam buffer of claim 1, wherein each flex beam has a semicircular profile that provides a curved contact surface in pressure contact with the upper pole. The method of claim 1, further comprising: providing a flat sheet of material, stamping the flat sheet of material to form the platform and the flex beam, and bending the flex beam at a desired angle with respect to the platform. And a beam buffer formed by a process comprising the steps. (a) a housing; (b) a rotatable disk supported in the housing; (c) a voice coil motor having a pole comprising a layer of magnetically permeable material; And (d) a shock absorber for a voice coil motor located between the housing and the pole, the beam buffer comprising: (d1) a substantially flat platform secured to a selected one of said housing and said pole; And (d2) a plurality of flex beams extending from the platform at an angle selected with respect to the platform, each contacting the remaining one of the housing and the pawl to resiliently position the housing relative to the voice coil motor; Disk drive. 7. The disk drive of claim 6, wherein an end of each flex beam is covered by a vibration-absorbing material. 7. The disc drive of claim 6 wherein each flex beam has a semicircular side providing a curved contact surface in pressure contact with the remaining one of the housing and the pawl. 7. The disk drive of claim 6, wherein the number of the flex beams is at least four. 7. The method of claim 6, wherein the beam buffer provides a planar sheet of material, stamping a planar sheet of material forming the platform and the number of flex beams, each flex at a desired angle with respect to the platform. And formed by a process comprising bending the beam.