JPH0536655U - VCM actuator for magnetic head drive of magnetic disk device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a structure of a VCM actuator for driving a magnetic head, which can be downsized and which can improve vibration resistance, impact performance and shorten positioning time. A VCM actuator for driving a magnetic head of a magnetic disk device, in which a magnetic head 1 is provided on one side of a swing arm 7 via a magnetic head suspension 6 around a rotating shaft 2 and a drive coil 5 is provided on the opposite side. A balance weight 3 made of a non-magnetic material having a specific gravity of 15 g / cm ³ or more is fixed between the rotary shaft 2 and the drive coil 5 with a screw 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a swinging magnetic head driving VCM actuator for a magnetic disk device.

[0002]

[Prior Art]

 The VCM actuator for driving the magnetic head of the magnetic disk device is generally divided into two types: a straight-advance type and a swing type. The oscillating type has a smaller inertia than the straight-ahead type and is advantageous for speeding up the seek time. However, the oscillating arm rotation center position of the magnetic head driving VCM actuator and the center of gravity of the oscillating portion around the rotation direction are If the position shifts, even a small impact or vibration will greatly affect the positioning accuracy. In addition, the positioning servo time is extended due to the displacement of the center of gravity. Further, in a large-capacity magnetic disk device, a large number of magnetic heads are mounted, and therefore the center of gravity of the rotation center and the center of gravity of the oscillating portion easily deviate, and the center of gravity is often displaced from the center of rotation of the actuator toward the magnetic head. . In order to solve this problem, conventionally, as shown in FIG. 1, balance weights 3 for adjusting the center of gravity made of SUS-based or Fe-based metal material are provided on both sides of the mounting portion of the coil 5 of the swing arm 7. Although it was added, the balance weight for adjusting the center of gravity became very large and it was difficult to attach it to the swing arm 7 in order to reduce the size, increase the capacity, and reduce the thickness. In addition, there was a problem that the use of magnetic materials would affect the magnetic circuit created by VCM.

[Problems to be solved by the device]

 An object of the present invention is to provide a magnetic head driving VCM actuator that can be made smaller than the conventional structure, and that can improve vibration resistance, impact performance, and shorten positioning time.

[0004]

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention provides a magnetic disk drive in which a magnetic head is provided on one side of a swing arm via a magnetic head suspension and a drive coil is provided on the opposite side about a rotation axis. In the head driving VCM actuator, a balance weight made of a non-magnetic material having a specific gravity of 15 g / cm ³ or more is screwed between the rotating shaft and the driving coil. As the material of the balance weight used for the implementation of the present invention, an alloy containing 97% W, 1.8% Ni and 1.2% Cu (specific gravity 18.5 g / cm ³ ), and tungsten (specific gravity 19 .3g / cm3), platinum (specific gravity 21.37g / ^cm 3), there are gold (density 19.3 g / cm @ 3) and the like.

[Action]

In the magnetic disk device, if the center of gravity of the swing arm of the swing arm equipped with the magnetic head of the VCM actuator for driving the magnetic head is displaced from the center of gravity of the swing portion, when a vibration or impact is applied in the movable direction, Since the force is applied to the position of the center of gravity, the swinging part easily moves and the position of the magnetic head is displaced. The present invention has a structure in which a balance weight made of a non-magnetic material having a specific gravity of 15 g / cm ³ or more is added between the rotating shaft on the side opposite to the magnetic head of the swing arm and the drive coil, and the position of the center of gravity in the rotating direction is Since the rotational center of gravity of the swing arm is matched, even if a vibration or impact is received, the force is applied to the center axis of rotation, and the swing part can be stable and downsized.

[0005]

【Example】

FIG. 2 shows an embodiment in the case of being applied to a magnetic head driving VCM actuator of a 3.5-inch thick hard disk drive, in which W is 97%, Ni is 1.8%, and Cu is 1.2%. % Of the balance weight 3 made of alloy of 10% from the rotation center on the side opposite to the magnetic head 1 with the rotation center of the swinging arm 7 carrying the magnetic head 1 as a boundary (12 mm in the embodiment). The balance weight 3 is attached to the oscillating arm 7 at two positions on both ends by screws 4 in the direction of the arrow in FIG. 2B. The balance weight 3 has a counterbore in the screw mounting portion so that the screw head is hidden in the balance weight 3. In this embodiment, when the balance weight 3 is not provided, the position of the center of gravity of the oscillating portion around the rotational direction is displaced from the center of rotation of the oscillating arm 7 in the direction of the magnetic head 1 mm (4 mm in the embodiment). In order to withstand high-speed access of 20 ms or less and 1G vibration and 5G shock during operation of the hard disk drive, the displacement of the center of gravity must be kept within a few hundreds of microns (200 microns in the example). There is a point. For this purpose, a balance weight of several g to several tens of g (4 g in the embodiment) is required, but with the conventional balance weight material (SUS, Fe system, etc.), since the specific gravity is 8 g / cm ³ or less, the volume is It becomes too large to fit within the standard dimensions, and the swing arm to be attached is too small to be attached. On the other hand, according to the structure of the embodiment, the balance weight 3 is attached in the vicinity of the rotation center of the swing arm 7 (12 mm from the rotation center in the embodiment) so that the balance weight 3 can be easily attached in a small size and is non-magnetic, so that the magnetic head is provided. The position of the center of gravity of the swing arm can be easily adjusted accurately without being affected by the magnetism generated by the VCM actuator for movement. Therefore, vibration resistance, improved shock performance, shorter positioning time, and shorter seek time as well as high-speed access, as well as downsizing, large capacity, and thinning can be realized.

[0006]

[Effect of the device]

 As described above, according to the present invention, it is possible to improve vibration resistance and impact performance by making the center of rotation of the oscillating portion of the magnetic head driving VCM actuator coincide with the center of gravity of the oscillating portion in the rotational direction. A VCM actuator for driving a magnetic head of a small-sized, large-capacity and thin magnetic disk device capable of high-speed access by shortening positioning time and seek time can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view and a side view of a conventional magnetic head driving VCM actuator.

FIG. 2 is a plan view and a side view of an embodiment of the present invention.

[Explanation of symbols]

 1 magnetic head 2 central axis of rotation of actuator 3 balance weight 4 balance weight mounting screw 5 drive coil 6 magnetic head suspension 7 swing arm

Claims (1)

[Scope of utility model registration request] 1. A magnetic head is provided on one side of a swing arm about a rotation axis via a magnetic head suspension,
In a magnetic head driving VCM actuator of a magnetic disk device having a driving coil on the opposite side, a balance weight made of a non-magnetic material having a specific gravity of 15 g / cm ³ or more is screwed between the rotating shaft and the driving coil. A VCM actuator for driving a magnetic head, characterized in that