Hard drive that has a head load/unload ramp including identically compliant slope blocks
Publication Date: 2014-Mar-11
The IP.com Prior Art Database
Disclosed is a disk drive that has a head load/unload ramp with slope blocks whose stiffness to disk contact are identical. This invention can improve hard drive’s operational-shock tolerance by reducing both disk displacement and acceleration. Disk vibration generated by operational-shock cause disk-ramp contact then large acceleration is generated on disk. The disk acceleration can lead head slider jump and damage recording media and recorded data. If ramp’s stiffness is low, the disk acceleration by disk-ramp contact should be low. However, it leads large disk displacement and disk should hit an arm finally. Because arm has relatively high stiffness, the disk-arm contact generates harmful disk acceleration. In this invention, when disk-ramp contact is caused by operational-shock, disks in a drive hit to ramp slopes in same manner and have same reaction force from the ramp slopes. This minimizes contact force by disk-ramp hit and improves operational-shock tolerance of the disk drive. Moreover, the stiffness of ramp slopes is optimized for minimize both displacement and acceleration of disks. Generally, a ramp naturally has different stiffness between end- and mid-side blocks because an end-side block has one slope and mid-side block has tow slopes and height of end-block is shorter than one of mid-side block. Therefore, large acceleration or large displacement is seen in a certain disk, and op-shock tolerance of the drive becomes lower.
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Disclosed is a HDD that has plural disks and a Ramp, and Ramp consists of,
- Fixed Block to be fixed to HDD base plate,
- Slope Surface to lift up suspension lift-tab,
- Parking portion to locate suspension lift-tab on it when the HDD is non- operational condition,
- and recess portion that accommodates disk with some gap.
- The recess portion make bodies that are remained near the ramp one end surface that will contact to disk in shock condition, which is called Contact Block.
and there are plural contact blocks with the Ramp that belong to 2 groups,
1. End-side contact blocks locates on the top surface and bottom surface of the Ramp
2. Mid-side contact block (or blocks) locates on the middle height position of the Ramp
and by adjusting the thickness of Contact Block,
adjusting the thickness bridge portion between Ramp central body to the tip portion of Contact Blocks,
and adding support feature (chamfer) to the Contact Blocks,
all Contact Blocks have nearly same level of bending stiffness.
Bending stiffness is defined as the ratio that the reaction force value divided by the Z-direction displacement when the Disk edge moves up or down.
The bending stiffness of Contact Blocks is made to be at least 38 N/m and to be no more than 84 N/m. This stiffness is achieved by adjusting their shapes or dimensions.
Figure 1, 2, and 3 show schematics of a hard disk drive and details of a ramp.
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Fig.1 Top view of hard disk drive (top cover is hidden)
Fig.2 Ramp, disk and head suspension
Fig.3 Contact blocks of ramp
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Figure 4 shows an embodiment of this invention with support feature. In the present invention, there is a chamfer at the root of the bridge portion between the ramp central body and the End-side contact block. This increases the bending stiffness of the End-side contact block and makes it close to the bending stiffness of the Mid-side contact blocks.
Ramp (Related Art) Ramp (The Present Invention)
Fig. 4 Embodiment of the invention with support feature to Contact Blocks
By increasing bending stiffness of the end-side contact block, displacement of end-disk generated by operational-shock is reduced. Figure 5 compares simulation results between the prior art and the present invention. Each bar represents for maximum relative displacement between mount plate and disk corresponding to each head. This figure shows the relative displacement...