JPH0432081A - Negative pressure slider and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a negative pressure slider and a method for manufacturing the same.

Several composite magnetic head sliders used in hard disk drives have been announced in which the principle of negative pressure generation is applied to the floating of the slider.

The advantages of using negative pressure are that the pressing force that presses the slider from the outside is weak, so a low flying height can be obtained, and that the flying height is less dependent on speed.

The negative pressure slider proposed by the present inventors requires approximately half the external pressing force of the negative pressure slider to achieve the same flying height, and the speed dependence is sufficiently smaller than that of the positive pressure slider. It is.

Another feature is that the negative pressure generating section is formed into a two-stage groove.

Furthermore, the method for manufacturing a negative pressure slider proposed by the present inventors is characterized by the use of an end face processing tool.

"Conventional technology" First, an example of the positive pressure slider 101 is shown in FIG.

It consists of two parallel rails 102 and this rail 10.
2 and a magnetic disk (not shown) facing the slider 101 at a height where the floating blade that pushes up the slider 101 and the pressing force that presses the slider 101 from the outside by spring force etc. are balanced. floats to the surface.

Note that the reference numeral 103 is a magnetic core.

Next, FIG. 6 shows a typical example of the negative pressure slider 106. That is, there is one cross rail 108 connecting two parallel rails 107, and this cross rail 10
The groove on the downstream side of 8 becomes the negative pressure generating section 109. In addition, the code|symbol 110 is a magnetic core.

The negative pressure is generated depending on the distance between the cross rail 108 and the opposing magnetic disk (not shown), the depth of the negative pressure generating section 109, and the area of the negative pressure generating section 109. For example, when the floating height of the crossrail 108 is about 0.1 μs, the negative pressure is greatest when the depth of the negative pressure generating portion 109 is around 1-1, and as the depth of the negative pressure generating portion 109 becomes deeper, the negative pressure becomes larger. The pressure becomes weaker. Furthermore, the larger the area of the negative pressure generating section 109, the larger the negative pressure. The negative pressure slider 106 floats with a flying height that balances the negative pressure generated in this way with the pressing force from the outside, such as a spring that presses down the negative pressure slider 106.

Figure 7 shows a positive pressure slider 101 and a negative pressure slider 106.
The speed-flying height characteristics of

The floating blade of the negative pressure slider 106 becomes larger toward the outer periphery of the magnetic disk (higher circumferential speed), and the flying height increases, but the absolute value of the negative pressure applied to the negative pressure slider 106 also increases, so the positive pressure Compared to the slider 101, the negative pressure slider 106 has a smaller flying height at the outer circumference.

Also, when the slider is on the inner circumference of the magnetic disk,
Alternatively, when the magnetic disk starts rotating, almost no negative pressure is applied to the slider, and the spring pressure of the spring that holds the slider down is weak, so the negative pressure slider 106 floats up faster and there is a risk of damage due to rubbing against the magnetic disk. The pressure is lower than that of the positive pressure slider 101.

In actual use, the slider is placed at an angle to the streamline of the airflow at the outer periphery of the magnetic disk.
There is a drawback that the flying height decreases too much because the number of floating blades due to positive pressure decreases, while the negative pressure remains unchanged. In order to compensate for this, for example, as shown in FIG. 8, a notch 117 is carved in the middle of the positive pressure rail 116 to prevent the positive pressure from decreasing due to the 5KE-angle. In addition, the code|symbol 118 is a cross rail, 119 is a negative pressure generation part, and 120
is the magnetic core.

"Problem to be Solved by the Invention" By the way, the depth of the negative pressure generating portion of the negative pressure slider is several minus, and the accuracy is required to be about ±0.3go+. In order to provide this negative pressure generating part, the conventional technology uses ion etching to meet this requirement, but the depth is 1.
It takes about 1 hour to process 01m, which is extremely inefficient. Therefore, it is desirable to be able to process using other processing methods with good processing efficiency.

Cutting out the middle of the positive pressure rail to prevent the floating blade from decreasing due to the SKE angle also affects the distribution of negative pressure, causing the pressure center of positive pressure and negative pressure to become unbalanced. Further, the depth of the notch must be made shallower than the negative pressure generating part, which requires complicated processing (Japanese Patent Application Laid-open No. 110680/1983).
.

In the positive pressure slider shown in FIG. 8, by narrowing the width of the rail 116, a slider with a low load and low speed dependence can be obtained.

However, in reality, since the magnetic core 120 exists at the outflow end of the positive pressure rail 116, the width of the rail 116 is set to 0.35.
It is difficult to make it narrower than the cabinet.

In addition, in a single conventional negative pressure slider in which the depth of the negative pressure generating part is the same everywhere, as shown qualitatively in Figure 9, the pressure is Since the center is balanced and the pressure center moves toward the inflow side on the outer circumferential side of the magnetic disk, the flying posture has a large pitching (angle of attack), and the slider's ability to follow the swing of the magnetic disk becomes poor. Furthermore, a larger negative pressure than necessary is generated on the outer circumferential side of the magnetic disk, so if the negative pressure generating part is made deeper in order to adjust this, the negative pressure on the inner circumferential side will become too weak. I can't.

``Means for Solving the Problems'' In view of the above circumstances, the present invention has been developed to provide a negative pressure slider with an external pressing force that is approximately half that of a positive pressure slider, resulting in the same flying height and a positive speed dependence. In order to make it sufficiently smaller than the pressure slider, the section between the cross rail and the negative pressure generating section is formed into an arc R, and a negative pressure relief section is provided that is further recessed from the negative pressure generating section to the airflow outflow side. It is something that

In addition, in view of the above circumstances, the present invention aims to replace the negative pressure generating part of the negative pressure slider with another processing method with high processing efficiency in the direction of air flow on the surface facing the magnetic disk. A method for manufacturing a negative pressure slider in which positive pressure rails are provided on both sides of the slider, a cross rail is provided to connect the positive pressure rails, and a portion surrounded by both positive pressure rails and the negative pressure rail is a negative pressure generating section. , a method for manufacturing a negative pressure slider in which a negative pressure generating portion is formed by rotating an end face processing tool.

"Example" FIG. 1 shows a negative pressure slider according to the present invention.

This slider is made of calcium titanate, has a roughly rectangular parallelepiped shape, has an overall width of 3.2 m, and a length (in the direction of air flow) of 4.
It is 5 meters long and 0.8 kaku in height. Width 0 on both sides in the length direction (air flow direction) of the surface facing the magnetic disk (not shown)
．． Two positive pressure rails 1 of about 4 m, and two 1.1 m + groove-shaped grooves with the same arc R depth 4 facing each other in the direction of air flow.
The cross rail 2 is composed of the negative pressure generating part 3 and the positive pressure relief part 5 of a, and the cross rail 2 and the negative pressure generating part 3 are arranged in the same arc R of 1.1 to further control the negative pressure. It consists of a negative pressure relief part 4 having a depth of 104 or more from a groove-shaped negative pressure generating part 3 which is further recessed from the circular arc R to the outflow side of the air flow. The negative pressure generating section 3 is surrounded on three sides by the positive pressure rail 1 and the cross rail 2, and a negative pressure relief section 4 is connected to the downstream side. On the inflow side of the cross rail 2, there is a groove-shaped positive pressure relief part 5.

In addition, the code|symbol 6 is a magnetic core. This negative pressure slider is pressed with a spring pressure of 5 gr.

FIG. 2 compares the negative pressure between the case where the negative pressure generating section 3 has the negative pressure relief section 4 and the case where the negative pressure relief section 4 is not provided. If there is no negative pressure relief section 4, there will be a large difference in negative pressure between the outer circumference and the inner circumference of the magnetic disk. This means that if the necessary negative pressure is obtained at the inner periphery, the negative pressure becomes too strong at the outer periphery. On the other hand, by increasing the width of the positive pressure rail l,
One idea would be to make the negative pressure generating part 3 shallow and wide to balance it without providing the negative pressure relief part 4, but in this case, the effective pressing force (spring force + negative pressure) would become excessively large, and conversely the magnetic disk This worsens the slider's ability to follow vibrations.

From the perspective of damping performance, the effective pressing force is the rail width equal to 1 mm of the rail length. It is said that 5 to 1 Ogr is good for the case of about 5 to 10 gr. Therefore, the floating blade on the inner peripheral side is 9.5 gr (a value generally used in positive pressure sliders at present).

It is appropriate to create a positive pressure rail 1.2 and share the pressure between the suspension and negative pressure.

For this purpose, the negative pressure relief part 4 of the negative pressure generating part 3 as in the present invention is extremely important.

Characteristic curve C of the negative pressure slider in FIG. 7 is the speed-flying height characteristic of the negative pressure slider according to the present invention.

It can be seen that the flying height at the outer periphery of the magnetic head is lower than that of a positive pressure slider with the same rail width or the same load.

The effective pressing force at the inner peripheral portion of the magnetic disk is 9 to 10 gr, and the damping effect is also appropriate. In addition, in actual use, the 5KEW effect is added at the outer periphery, so the flying height is approximately 10%.
The difference between the inner and outer circumferences further becomes smaller.

The reason why the cross rail 2 is shaped like an arc is due to the following three reasons.

If the cross rail 2 is made into an arc shape, first, it can be processed by the end face lapping method.

According to this end face lapping method, the negative pressure generating portion 13 of the negative pressure slider can be processed in a short time and with high precision.

Next, since both ends of the cross rail 2 expand in an arc shape and are connected to the positive pressure rail 1, even if a 5KE-angle is given, the distance that air passes over the rail becomes longer, compensating for the decrease in positive pressure. be able to. This cross rail has a ramp section (
Since there is no air intake (air intake part), positive pressure builds up gradually instead of suddenly. Therefore, if the S)[E- angle is not given, the positive pressure will not become abnormally large due to this crossrail.

FIG. 4 shows an example of the pressure distribution of this negative pressure slider. The figure shows the pressure distribution for half of the slider, and it can be seen that negative pressure is generated in the center.

Furthermore, by dividing the negative pressure into the inflow side and the outflow side, the pressure center on the outer circumferential side of the magnetic disk moves toward the inflow side, increasing pitching, which causes the pressure center to move upstream, albeit slightly. can be held down.

Further, the dimensional tolerances of each part of this negative pressure slider are determined from the following viewpoints.

By changing the depth of the negative pressure generating part by ±0.52 ffil, the pressure changes by ±0.8 to ±1.1 gr.

If the length of the negative pressure generating section is changed by ±50 Jjl, the floating blade will change by ±1.2 gr at the outer circumference of the magnetic disk.

If the crossrail position is moved by ±50°, the entire center of pressure will move by ±0.28° at the outer periphery.

If the depth of the positive pressure relief section and the negative pressure relief section in front of the cross rail is 10 m1 or more, it will not affect the floating blade. If the width of the positive pressure rail is changed by 29-, the flying height will be ±0.01m.
Since it fluctuates by 1, this can be used to make minute adjustments to the flying height.

Next, a manufacturing method according to the third aspect of the present invention will be explained in detail. As mentioned above, the principle of the end lapping method is shown in Fig. 3, in which two workpieces 12 that are machined to become sliders are placed adjacent to each other on a surface plate 10, and their outer diameters are used to generate negative pressure. The wrapping agent 14 is applied to the work 12 and the wrapper 1 while rotating the wrapper 11, which is a hollow cylindrical end processing tool equal to the part 13, and traversing the work 12 in the longitudinal direction.
The negative pressure generating portion 13 is processed by supplying the material between the lower surface of the material and the lower surface of the material. When two workpieces 12 are placed on the surface plate 10 and machined, two workpieces can be machined by the same traverse of the negative pressure generating section 13. According to this end face lapping method, the negative pressure generating portion 13 of the negative pressure slider can be processed in a short time and with high precision. Although not shown, the negative pressure relief part is set to the same arc R as the negative pressure generating part 13, so the depth of cut is increased with the same wrapper 11, making it shorter than when machining the negative pressure generating part 13. Can be processed by traverse. Furthermore, since the positive pressure relief portions are also set to the same arc R, they can be processed using the same wrapper 11.

In this case as well, by arranging the positive pressure relief parts of the two workpieces 12 close to each other, it becomes possible to process the two positive pressure relief parts with the same truss of the wrapper 11.

This wrapper 11 is designed approximately 10mm from the surface to prevent the edge of the outer periphery from being worn out during use and the R of the edge forming the negative pressure generating part to increase, resulting in the width not being the specified width.
It is an extremely hard comb that has been specially treated to a depth of . Therefore, since the inner side of the end face of the wrapper 11 wears out faster than the outer periphery, the edge on the outer periphery is always kept sharp. The amount of wear on the workpiece is determined depending on the material, particle size, and load of the abrasive grains, and the operation of the wrapper 11 is controlled using a timer.

To give an example of this processing, when a processing pressure of 300 gr is applied using diamond abrasive grains with a grain size of 1 gm, the rotation speed of the wrapper 11 is 500 rpm +), the rubber speed is 60 times/sin, and the negative pressure generating part 13 is It takes about 3 minutes to process to a depth of 41 m.

In the above manufacturing method, the diameter of the wrapper 11, which is a hollow cylindrical end face processing tool, is equal to the width of the negative pressure generating part 13, and the workpiece 12 is machined by driving in the longitudinal direction. The width of the wrapper 11 may be made smaller than the width of the negative pressure generating section 13, and the wrapper 11 may be ground by a partitioned portion between the positive pressure rail 1 and the cross rail 2 while rotating.

Furthermore, in the manufacturing method of the present invention, it is not necessary to make the section with the cross rail 2 into an arc R, and the wrapper 11a is placed only at the intersection of the positive pressure rail 1 and the cross rail 2, as shown in FIG. 3(C). A circular arc R may be provided.

"Effects of the Invention" Since the present invention has the above-described configuration, it presses the magnetic disk with a smaller load than a positive pressure slider that obtains the same flying height, so the magnetic disk is There is little damage to the slider and magnetic disk caused by rubbing.

Furthermore, since the present invention allows the flying height at the outer peripheral portion of the magnetic disk to be kept low, higher density recording and reproduction is possible.

Furthermore, since the present invention has a negative pressure relief section compared to conventional negative pressure sliders, the inner periphery of the magnetic disk is sufficient.
Negative pressure that does not become excessive at the outer periphery can be obtained.

Furthermore, in the present invention, the reduction in flying height due to 5KE-angle is small.

According to the manufacturing method of the present invention, when the negative pressure slider is processed by the end face lapping method, high efficiency and low cost can be obtained.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the negative pressure slider of the present invention, Fig. 2 is a comparison of negative pressure when the negative pressure slider has and does not have a negative pressure relief section, and Fig. 3 is a negative pressure of the present invention. A diagram illustrating a method of manufacturing a slider, in which (a) is a front view;
Figure (c) is a plan view of figure (a), figure (C) is a plane view showing another embodiment of the manufacturing method of the present invention, and Figure 4 shows an example of the pressure distribution of the present negative pressure slider. Fig. 5 is a perspective view of a conventional positive pressure slider, Fig. 6 is a perspective view of a conventional negative pressure slider, Fig. 7 is a speed-flying height characteristic diagram of a positive pressure slider and a negative pressure slider, and Fig. 8 9 is a perspective view of an example in which a notch is carved in the positive pressure rail of a conventional negative pressure slider, and FIG. 9 is a diagram showing pressure center positions of a conventional positive pressure slider and a negative pressure slider. 1... Positive pressure rail 3... Negative pressure generating section 2... Cross rail 4... Negative pressure relief section Fig. 1 Fig. 2 Inner circumference outer circumference magnetic disk No. 3 1I (C) Fig. (b) ) Inner circumference speed m/s Outer circumference lower magnetic disk

Claims (3)

[Claims] (1) Positive pressure rails are provided on both sides of the surface facing the magnetic disk in the airflow direction, and a cross rail is provided to connect the positive pressure rails, and the area is surrounded by both positive pressure rails and the cross rail. 1. A negative pressure slider in which a section between a cross rail and a negative pressure generating section is formed into an arc R. (2) Positive pressure rails are provided on both sides of the surface facing the magnetic disk in the airflow direction, and a cross rail is provided to connect the positive pressure rails, and the area is surrounded by both positive pressure rails and the cross rail. In a negative pressure slider in which the negative pressure generating part is a negative pressure generating part, a dividing part between the cross rail and the negative pressure generating part is formed into an arc R, and a negative pressure relief is further recessed from the negative pressure generating part to the airflow outflow side. A negative pressure slider characterized by having a section. (3) Positive pressure rails are provided on both sides of the surface facing the magnetic disk in the airflow direction, and a cross rail is provided to connect the positive pressure rails, and the area surrounded by both positive pressure rails and the cross rail is provided. 1. A method of manufacturing a negative pressure slider in which a portion of the negative pressure generating portion is a negative pressure generating portion, the negative pressure generating portion being formed by rotational machining of an end face processing tool.