JPH0442423A - Magnetic head for magnetic disk device - Google Patents

Abstract

PURPOSE:To perform the positioning control of a magnetic head by using the data information of a data track by reducing the width of the gap parts of two servo cores to the half of that of the gap part of a data core, and arranging the gap parts of the two servo cores at a position symmetric to the center line of the width of the gap part of the data core. CONSTITUTION:One data core 10 to perform the read/write of data, and the two servo cores 20, 30 to read out positioning information of servo system are provided on the floating plane of the magnetic head. The width of the gap parts 21, 31 of the servo cores 20, 30 are formed in the half that of the gap part 11 of the data core 10, and the gaps 21, 31 are arranged at the position symmetric to the center line L-L of width of the gap part 11, and set in parallel with the gap part 11. In such a way, the positioning control of the magnetic head following the data information can be performed by inputting the difference of output of the readout signals of the servo cores 20, 30 to a servo positioning control circuit as an error voltage, and controlling the error voltage so as to be zero.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head used in a magnetic disk device.

[Conventional technology]

In recent years, as the density of magnetic disk devices has increased, various servo-based magnetic head positioning systems have been developed in order to improve the radial recording density (track density) of magnetic disks.

For example, in the dedicated servo magnetic/rad positioning method, servo information written in advance on a dedicated servo magnetic disk (servo surface) is read out using a dedicated servo magnetic head (servo head) for positioning. The magnetic head (data head) is of a type that determines the position by mechanically interlocking with a servo head. In addition, the index servo method and sector servo method magnetic head positioning methods use a data head to read servo information written on a part of a magnetic disk (data surface) for data recording, and position each data head accordingly. In the conventional magnetic head used in such a magnetic disk device, one magnetic head has one
It has two data cores and one servo core.

[Problem to be solved by the invention]

Among the magnetic heads of the conventional magnetic disk drives mentioned above, dedicated servo type magnetic disk drives require a dedicated servo surface in addition to the magnetic disk for data recording, and therefore have a correspondingly smaller storage capacity. Moreover, since the data head and the servo head are located at different positions, there is a drawback that 5 off-track occurs if the relative positional relationship between them cannot be maintained. Furthermore, index servo type and sector servo type magnetic disk drives have a drawback in that special servo information must be written in advance on a portion of the data surface.

[Means to solve the problem]

A magnetic head of a magnetic disk device according to the present invention has one data core for reading and writing data, and two servo cores for reading positioning information of a servo system, and the two servo cores The width of the gap portion of the data core is half the width of the gap portion of the data core, and the gap portions of the two servo cores are provided at symmetrical positions with respect to the center line of the width of the gap portion of the data core. Further, the gap portion of the servo core and the gear portion of the data core are parallel to each other.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing the core position of the air bearing surface in an embodiment of the present invention, and FIG. 2 is a plan view showing the relationship between the core and data track in the embodiment of FIG.

The embodiment shown in FIG. 1 includes one data core 10 for reading and writing data, and two servo cores 20 and 30 for reading servo positioning information on the air bearing surface of the magnetic head. It has data core 10
The width of the gap portion 11 of the servo cores 20 and 30 is W, and the width of the gap portions 21 and 31 of the servo cores 20 and 30 is 1/2W, which is half the width of the gap portion 11 of the data core 10. The gap portions 21 and 31 of the servo cores 20 and 30 are aligned with the center line L-L of the width of the gap portion 11 of the data core 10.
It is placed in a symmetrical position with respect to the Furthermore, the gap portions 21 and 31 of the servo cores 20 and 30 are parallel to the gap portion 11 of the data core 10.

Next, the operation of the above-mentioned embodiment will be explained with reference to FIG.

FIG. 2(a) is a plan view showing the state when the magnetic head is accurately positioned on the data track 50.
Gap part 1 between data track 50 and data core 10
1 and the gap portion 21 of the servo cores 20 and 30
and 31 have their center lines coincident with each other, and the entire width of the gap portion 11 of the data core IO lies on the data track 50. Therefore, the output of the read signal of the data core 10 shows the maximum value, and the entire width of the servo cores 20 and 30 is in the data track 50-F, and the output of their read signals are at the same level.

(The arrows in the figure indicate the magnetization direction.) FIG. 2(b) is a plane view showing the state when the magnetic head is not accurately positioned on the data track 50 and is misaligned. In the figure, the center lines of the gap portion 11 between the data track 50 and the data core 10 and the gap portions 21 and 31 of the servo cores 20 and 30 do not coincide with each other.
A part of the width of the first part 11 is out of the data track 50, so the output of the read signal of the data core 10 is
It is lower than the case in Figure (a). Also, servo core 20
A part of the width of the gap portion 21 of the servo core 30 is off the data track 50, while the entire width of the gap portion 31 of the servo core 30 is on the data track 50. Therefore, the output of the read signal from the servo core 30 is larger than the output of the read signal from the servo core 20. The difference between the read signal outputs of the servo cores 20 and 30 is input as an error voltage to a servo positioning control circuit (not shown), and the positioning of the magnetic head is controlled by controlling this error voltage to zero. be able to.

〔Effect of the invention〕

As described above, the magnetic head of the magnetic disk device of the present invention includes one data core for reading and writing data, and two servo cores for reading servo-type positioning information. The width of the gap between the two servo cores is half the width of the gap between the data cores, and 2
By arranging the gap portions of the servo cores at positions symmetrical to the center line of the width of the data core gap portion, it is possible to control the positioning of the magnetic head using the data information of the data track. Therefore, there is an effect that positioning control of the magnetic head can be performed without using special servo information written in advance on a dedicated servo surface or data surface. Furthermore, since it is a servo system that follows data information, it has the advantage of being able to perform accurate positioning control.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the core position of the air bearing surface in an embodiment of the present invention, and FIG. 2 is a plan view showing the relationship between the core and data track in the embodiment of FIG. 10... Data core, 1]... Data core gap section, 20, 30... Servo core,
21・31・・・Servo core gap part, 50・
...Data track.

Claims (1)

[Claims] 1. It has one data core for reading and writing data, and two servo cores for reading positioning information of the servo system, and a gap portion between the two servo cores. The width of is half the width of the gap part of the data core,
A magnetic head for a magnetic disk device, characterized in that the gap portion between the two servo cores is provided at a symmetrical position with respect to the center line of the width of the gap portion of the data core. 2. It has one data core for reading and writing data and two servo cores for reading positioning information of the servo system, and the width of the gap between the two servo cores is determined by the width of the gap between the two servo cores. half the width of the gap,
The gap portions of the two servo cores are provided at symmetrical positions with respect to the center line of the width of the gap portion of the data core, and the gap portion of the servo core and the gap portion of the data core are parallel to each other. magnetic head of a magnetic disk device.