1. Field of the Invention
The present invention relates to a spindle motor and a hard disk drive including the same.
2. Description of the Related Art
A hard disk drive (HDD), an information storage device, reads data stored on a disk or writes data to a disk using a read/write head.
A hard disk drive requires a disk driving device capable of driving the disk. In such a disk driving device, a small-sized spindle motor is commonly used.
Such a small-sized spindle motor frequently uses a hydrodynamic bearing assembly. A shaft, a rotating member of the hydrodynamic bearing assembly, and a sleeve, a fixed member thereof, have a lubricating fluid interposed therebetween, such that the shaft is supported by fluid pressure generated in the lubricating fluid.
In addition, an upper portion of the shaft is mounted with a rotor hub rotating together with the shaft and having a recording disk mounted thereon, wherein the rotor hub is fixedly coupled to the upper portion of the shaft and has a disk shape in which it is extended in a radial direction, based on the shaft. Therefore, the lubricating fluid may also be interposed between an upper surface of the sleeve and the rotor hub.
According to the related art, in manufacturing a base provided in the hard disk drive, a post-processing scheme of die-casting aluminum (Al) and then removing flash, or the like, generated due to the die-casting has been used.
However, in the die-casting scheme according to the related art, since a process of injecting aluminum (Al) in a molten state to make a form is performed, high degrees of temperature and pressure are required, such that a large amount of energy is required in the process and a process time and manufacturing costs increase.
Therefore, in order to solve the problems of the die-casting process, an attempt to manufacture the base by performing plastic working such as press working, or the like, on a steel sheet has been conducted. However, in the case of manufacturing the base by press working, since the base basically has a unique thickness, a problem may be generated in coupling a core to the base.
That is, in the case in which the base is manufactured in the die-casting process, the base may be provided with a step so as to allow the core to be seated thereon. However, in the case in which the base is manufactured by pressing a plate having a unique thickness, since the base has the unique thickness, it may be difficult to form a core seating part on the base.
In addition, for the same reason, in the case in which the base is manufactured by die-casting, the base may be provided with a step to seat the sleeve thereon. However, in the case in which the base is manufactured by pressing a plate having a uniform thickness, it may be difficult to couple the base and the sleeve to each other.