JPH0349394B2 - - Google Patents

Description

[Detailed Description of the Invention] <Summary> The characteristics of levitating the head of a magnetic disk are determined by the circumferential speed, the external force that changes depending on the shape and pressure conditions of the head, and the intersection angle between the axial direction of the head and the moving direction of the magnetic disk surface ( (commonly known as yaw angle).

On the other hand, for head access (track selection) in magnetic disk drives, there are two methods: one in which the head moves straight in the radial direction, and the other in which the head swings around a fulcrum.The latter inevitably causes a yaw angle, causing the recording track to move straight. Since the maximum value occurs at the innermost and outermost diameter portions of the plane, it is necessary to examine (confirm) the flying characteristics taking into account the influence of the yaw angle at least at the outermost and outermost diameter portions.

The present invention discloses a magnetic disk inspection apparatus that simultaneously satisfies the inspection condition of setting the yaw angle at the outermost diameter portion.

<Industrial Application Field> The present invention relates to a magnetic disk testing device, and more particularly to a testing device for testing the flying characteristics and read/write characteristics of a single disk, in which the characteristics are tested while the head is flying.

<Prior art and its problems> In the conventional test equipment, the track access method of the magnetic disk device was mostly a straight-line method, so the condition was basically that there was no yaw angle, and the test equipment also had a head for testing. A linear mechanism was used to move the.

However, in recent years, a method in which track access is performed by swinging the arm around its fulcrum has come into widespread use, and although this method inevitably produces a yaw angle, the flying characteristics and read/write characteristics are affected by the yaw angle. Since this is known, it has become necessary to perform inspections by taking the yaw angle into consideration, but since general-purpose inspection equipment uses a straight-line movement system, it is necessary to perform inspections by taking the yaw angle into account. If you try to measure the characteristics by changing the mounting angle, you will have to change the set angle each time, which poses a problem in terms of setup. Also, although it would be better to make a dedicated inspection machine, the cost of making an inspection device is not prohibitive, so if possible, I would like to make the inspection device as versatile as possible.

<Means for solving the problem and points of interest> In this application, in view of the above, the characteristics that need to be recognized for inspection are the characteristics at the innermost position where the yaw angle is maximum and at the outermost position in the case of a swing type. Another method is to focus on the fact that if the magnitude of the yaw angle is preserved, the positive and negative directions of the yaw angle do not affect the characteristics that much, and by setting the conditions by combining the two parameters in advance, all that is left is to adjust the flying head. The purpose of this invention is to enable inspection of the flying characteristics, etc. of both ends by simply moving between the innermost diameter part and the outermost diameter part. In order to achieve this, the magnetic disk inspection apparatus described above has a rotating means for rotating a magnetic disk as an object to be inspected, and a linear moving means for moving a measuring floating head in the radial direction of the magnetic disk. tilting the floating head at a predetermined angle α ₁ with respect to the moving direction of the linear moving means, and arranging the linear moving mechanism so that its moving direction passes through a position a predetermined distance X ₁ from the center of the rotating means; The predetermined angle α 1 and the predetermined distance X ₁ are set so that the yaw angle of the floating head becomes a predetermined yaw angle αin at the innermost radial position of the magnetic disk and a predetermined yaw angle _αout at the outermost radial position. An inspection device for a magnetic disk device is provided.

<Effect> If you use this method of setting, for example, αin=
If αout, then X ₁ = 0, α ₁ = αin, and α ₁ = αout, and if αin≠αout, then X ₁ ≠ 0, αout = α ₁ +
X ₁ /Rout, and αin=α ₁ +X ₁ /Rin. However, Rin and Rout are given in advance by the inner and outer radii of the track determined by the disk. Also, the angle is a radian, and X ₁ is an algebraic quantity that can be positive or negative depending on the direction. By making the above settings and moving the floating head, inspection of the innermost diameter portion and the outermost diameter portion can be carried out without changing the setup.

<Example> FIG. 1 is an explanatory diagram of an embodiment that also serves as a principle diagram of the present invention, and FIGS. 2 and 3 are supplementary explanatory diagrams of FIG. 1.

As is clear from the figure, the magnetic disk inspection apparatus to which the present invention is applied rotates the magnetic disk 1 with the center of rotation O ₁
A spindle and motor (both not shown) and rotation center O ₁ to rotate at a predetermined rotation speed
A movable base 2 whose degree of freedom is restricted while leaving a degree of freedom to move in a straight line direction extending more radially, a feed screw 3 for moving and positioning the movable base in the direction of the straight line, and the feed screw. 3, and a tilt block 5 which is adjustable in tilt in the rotational direction about a predetermined position P on the moving table 2 and an axis parallel to the axial direction of the spindle.
and a head arm 6 attached to the tilt 5,
A head 7 attached to the tip of the head arm 6
Let be the relevant element. Further, 8 is a means for monitoring the flying height.

In the relationship between the above related elements, if the straight line O ₁ O ₁ ′ drawn from the spindle center O ₁ to the axial center of the feed screw 3 when viewed from the direction perpendicular to the spindle axis direction is taken as the base line for shaft extension, then this base line O ₁ O ₁ ′ The direction of movement in the direction of the O ₁ O 1 ' line from O 1 O ₁ ' is the distance in the Y direction as y, and the plane direction perpendicular to this is the distance in the X direction as x, and the tilt of the head 7 attached to the tilt block 5 with respect to the X direction (installation 4) The angle is α ₁ , the offset distance from O ₁ O ₁ ' is x ₁ , and the distances from the magnetic disk rotation center O ₁ to the innermost diameter and the outermost diameter are Ri and Ro, respectively. If the yaw angle set as the test condition at the position of the outer diameter Ro is αout (the intersection angle between the moving direction of the disk and the head axis), and the yaw angle set at the innermost radius _R1 position is αin, then Among the above element quantities, αin, αout, Ri, and Ro are values given in advance for the disk test, and x ₁ and α ₁ are set values that can be changed freely during the test, so the disk is determined and tested. When the set inclination angle at the innermost and outermost diameter positions is given, simply moving the moving table in the Y direction will change αout and αin at the Ro and Ri positions, respectively.
In order to satisfy each of the following, it is sufficient to find solutions to the following simultaneous equations.

That is, αout and αin are as follows.

αout=sin ^-1 X ₁ /Ro+α ₁ ...(1) αin=sin ^-1 X ¹ /Ri+α ₁ ...(2) Here, | _{X 1 /} Ro| Even _if we approximate _it as sin ^-1 X ₁ /Ro≒X ₁ /Ro, sin ^-1 Therefore, αout, αin
is approximated as follows.

αout=X ₁ /Ro+α ₁ ...(1)' αinX ₁ /Ri+α ₁ ...(2)' Then, from the above simultaneous equations, X ₁ and α ₁ are approximated as follows.

x ₁ = (αout−αin)/(1/Ro−1/Ri) ……(3) α ₁ = (αout−Ri/Roαin)/(1−Ri/Ro)
...(4) In order to set X ₁ and α ₁ in the above equation, move the moving base 2
The upper tilting block 5 is moved in the X direction and the head arm 6 is rotated. And X ₁ ,
After setting _α1 , simply moving the moving table 2 will set αout at the respective positions Ro and αin at the respective positions Ri, making it possible to test the levitation characteristics near the positions Ro and Ri, which have strict criteria. can be executed under the same set conditions by monitoring the output corresponding to the flying height detected by the monitoring means 8 while moving the head.

Figure 2 shows the correspondence between changes in the tilt angle (yaw angle) when using an actual swing-type access arm and changes in the tilt angle when using this method. The absolute value is the same at the Ro or Ri position, but the direction of the slope will be different from the actual one in either case, and the midpoint between Ri and Ro will not match the actual one, so the middle part is more It can be seen that the inspection conditions are strict.

The situation is shown in FIG. 3. Between the case where the yaw angle is 0 and the case where the yaw angle is set to a predetermined angle, the flying height of the head tends to be lower in the latter case, and the monitoring output of the monitoring means 8 tends to be larger. There is.

<Effects> As explained above, according to the present invention, when testing the flying characteristics of a magnetic disk, it is possible to test the flying characteristics at the innermost diameter part and the outermost diameter part of the recording surface in conjunction with the yaw angle set in the actual device. This can be done using a general-purpose testing machine with a straight-line moving means, and the parameters
If x ₁ and α ₁ are selected, the yaw angle can be matched at the same time with the same parameter set at the outermost diameter portion, so testing can be performed without changing the set by simply selecting the same head position as in the normal case.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of an embodiment that also serves as a principle diagram of the present invention, and Figures 2 and 3 are supplementary diagrams of Figure 1, each explaining the correspondence of yaw angles and the monitoring output associated with yaw angles. This explains how to deal with this. In the figure, 1 is a magnetic disk, 2 is a moving table, 3 is a feed screw, 4 is a feed motor, 5 is a tilting block, 6 is a head arm, 7 is a head, 8 is a monitoring means, etc.
O ₁ is the rotation axis, line O ₁ O ₁ ' is the base line, x ₁ is the offset amount, α ₁ is the tilt setting angle of the head 7, αout and αin are the yaw angles at the outermost and innermost diameter parts. .

Claims (1)

[Scope of Claims] 1. A magnetic disk inspection apparatus comprising a rotating means for rotating a magnetic disk as an object to be inspected, and a linear moving means for moving a measuring floating head in the radial direction of the magnetic disk, comprising: The head is tilted at a predetermined angle α ₁ with respect to the moving direction of the linear moving means, and the linear moving mechanism is arranged so that its moving direction passes through a position a predetermined distance X ₁ from the center of the rotating means, The predetermined angle α ₁ and _the predetermined distance Features: Inspection device for magnetic disk devices.