JPH04298870A - Floating head loading/unloading mechanism - Google Patents

Abstract

PURPOSE:To enable dynamic loading/unloading capable of starting/stopping at complete non-contact state between a floating head and a magnetic disk medium. CONSTITUTION:The movement speed at the time of loading/unloading of a floating head slider 2 is controlled by an actuator driver 9 operating as partial function of a sine wave developed in time axis which is obtained by a driving function generator 10 electrically connected to a load/unload actuator (DC motor). Thus, an air lubrication surface 5 of the floating head slider 2 can approach or leave the surface of a magnetic disk medium 1 at a speed profile having an approximately single frequency characteristic within a frequency range, and the loading/unloading can be performed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loading/unloading mechanism for a floating head slider used in a magnetic disk drive.

0002

2. Description of the Related Art A magnetic disk drive uses a floating head slider having a magnetic head mounted on one end surface thereof. The floating head slider floats above the disk due to the mechanical effect of high-speed airflow generated by the high-speed rotation of the disk, and performs recording and reproduction while maintaining a small distance between the magnetic head and the recording medium. The gimbal spring allows the floating head slider to follow the surface protrusions and undulations of the disk while maintaining a constant spacing, allowing it to move freely in pitch, roll, and directions perpendicular to the disk surface. A load spring is attached to the gimbal spring, which simultaneously controls the flying height of the floating head slider and supports the head to move the magnetic head onto a desired recording track.

On the other hand, in current magnetic disk drives, as a start/stop method, the floating head slider and the disk are placed in contact with each other when the disk stops rotating.
Start the rotation of the disk, and as the rotation speed increases, the floating head slider levitates and performs normal operation.
When the disk stops, the disk rotation speed decreases, causing the floating head slider to land on the disk again, which is called a contact start/stop (C).
SS) method is the mainstream. In the CSS method, the floating head slider and the disk surface are in contact, low-speed sliding, separation, and
The machine is operated through various stages of low-speed sliding and contact, which can cause problems with friction and wear, and in some cases, this friction and wear can lead to head crashes.

[Problems to be Solved by the Invention] Although the CSS method has the advantage of having a simple structure, it has the following problems.

The first problem is the contact sliding problem that inevitably occurs during CSS. When the rotation speed of the disk reaches a certain speed or higher, sufficient levitation force is generated in the floating head slider, so that the floating head slider and the disk surface are kept out of contact. In this case, the buoyancy force acting on the floating head slider is small, so that the floating head slider and the disk slide while in contact with each other. Such contact sliding also occurs when the disk is stopped, in which case the floating head slider transitions from a fluid lubrication state to a contact state.

[0005] Floating head sliders are typically made of extremely hard materials such as ceramics. On the other hand, disks have a protective film made of carbon etc. to protect the magnetic recording layer, and a lubricant on the surface to reduce frictional resistance and suppress wear when sliding in contact with the floating head slider. However, due to the characteristics of magnetic recording, they are formed of thin films, so their hardness is lower than that of a floating head slider. Therefore, during contact sliding, there is a problem of frictional wear, and the fine frictional wear particles generated at this time may impede the stable movement of the floating head slider and lead to a head crash.

The second problem is that the finishing accuracy of the slider lubricating surface of the floating head slider, which will continue to be required to have a low floatation level, is required to be extremely smooth, and at the same time,
Since the disk surface is also required to have high flatness that does not interfere with the low flying height of the floating head slider, there is a risk that the floating head slider and the disk may stick together when the disk is stopped. Once adhesion occurs, the frictional force increases rapidly, making it difficult to start the disk.

[0007] Therefore, in order to avoid the above problems,
There is a need for a system for starting and stopping a disk device in which the floating head slider and the surface of the disk always operate without contact. There is a loading process in which the floating head slider mounted on the floating head slider support approaches the surface of the magnetic disk medium by force provided by some mechanical system, and a loading process in which the floating head slider is moved away from the surface of the magnetic disk medium. unloading is required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a floating head load/unload mechanism that eliminates such drawbacks and enables dynamic load/unload that realizes complete non-contact startup/stop between the floating head and the magnetic disk medium. It's about doing.

[0009]

[Means for Solving the Problems] The present invention provides a floating head slider, a gimbal spring consisting of a tongue-shaped plate spring supporting the floating head slider, the gimbal spring being joined to one end of the gimbal spring, and the floating head slider being connected to the gimbal spring at one end thereof. The floating head slider is moved above the surface of the magnetic disk medium by the movement of the floating head slider support by a load-unload actuator or a positioner actuator. A floating head load/unload mechanism for loading or unloading the floating head, the floating head slider being driven by the load/unload actuator or the positioner actuator in the normal direction to the magnetic disk medium surface during the loading or unloading operation. A drive function generator whose velocity component generates a drive pattern as a partial function expanded on the time axis of a sine wave that is considered to be approximately a single frequency in the frequency domain, and which is electrically connected to the load-unload actuator or the positioner actuator. It is characterized by having a container.

0010

[Operation] As shown in FIG. 1, the present invention controls the motion speed of the floating head slider 2 during loading and unloading by a drive function generator 10 electrically connected to a load/unload actuator (DC motor). It is controlled by an actuator driver 9 that operates as a partial function of the sine wave developed on the resulting time axis. Thereby, the air lubricated surface 5 of the floating head slider 2 approaches or moves away from the surface of the magnetic disk medium 1 with a speed profile having a substantially uniform frequency characteristic in the frequency domain, thereby performing loading or unloading.

Therefore, the present invention enables dynamic load-unloading that realizes complete non-contact starting and stopping of the floating head and magnetic disk medium.

0012

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

FIG. 1 is a side view showing one embodiment of a floating head loading/unloading mechanism according to the present invention. Although many configurations are possible for the floating head load/unload mechanism of the present invention, the most basic configuration will be explained here.

The floating head slider support body includes a floating head slider 2, a gimbal spring 4 that supports the floating head slider 2, and a gimbal spring 4 that is joined to one end thereof, and at the same time applies an appropriate load to the floating head slider 2. It consists of a load spring 3 in the form of a leaf spring and a spacer 6. Note that the spacer 6 is rigidly connected to a positioner mechanism (not shown).

As is well known, the load spring 3 includes:
An initial load is applied so that the load acts in the Z- (minus) direction shown in FIG. It is held by arm 110. In FIG. 1, floating head slider support support arm 110 is shown in cross section. The floating head slider support support arm 110 is fixed to one end of a load-unload arm 113, which is rotatably held by a rotating shaft 115 at its center. The other end of the load-unload arm 113 is wrapped around a DC motor output shaft 114 via a steel belt 112. The DC motor 111 is driven by an actuator driver 9 to which a drive function generator 10 is further electrically coupled.

When looking at this embodiment as a load-unload mechanism, FIG. 1 shows a state in which the floating head slider 2 is unloaded. The air lubricated surface 5 of the floating head slider 2 is held a spacing h away from the surface of the magnetic disk medium 1. This spacing h is achieved by the fact that one end of the load/unload arm 113 on the DC motor 111 side swings in the θ direction via the steel belt 112 due to the rotation of the DC motor output shaft 114, centering on the rotation axis 115. The head slider support support arm 110 is lowered in the Z-direction in the figure, and the air lubricating surface 5 approaches the position where it floats above the magnetic disk medium surface with a submicron gap, so that the floating head slider 2 will be loaded. Unloading is the opposite process.

In this loading/unloading operation, the floating head slider support arm 110 controls the movement of the floating head slider 2. This movement of the floating head slider 2 greatly affects the head-medium interface reliability of load-unload operations. Here, if this floating head slider support has an extremely rigid structure, the movement of the floating head slider 2 and the movement of the floating head slider support support arm 110 exhibit similar characteristics except for the amount of displacement. . However, as is well known, floating head slider supports are relatively flexible spring structures, which can, in some cases, cause the relationship between them to be disrupted. This indicates a case where the movement of the floating head slider 2 cannot be controlled by the floating head slider support support arm 110.

Considering this from the perspective of the head-medium interface, the behavior of the floating head slider during loading or unloading, especially the movement speed of the slider, is greatly affected by the reliability of the interface. It is clear that the reliability of the head-medium interface can no longer be guaranteed, especially if its speed of movement becomes uncontrollable. In FIG. 1, a drive function generator 10, which is electrically coupled to the actuator driver 9, modulates the movement of this floating head slider support support arm 110 into a sinusoidal wave spread out in the time domain. The movement is controlled via the actuator driver 9 according to the function.

FIG. 2 shows the velocity of movement of the floating head slider support support arm during a loading operation, where profile a is controlled according to a subsinusoidal function generated by a drive function generator used in an embodiment of the invention. Profile b shows the behavior of velocity as a function of time, which is realized by general constant acceleration motion. Here, the target operating speed of the floating head slider 2, that is, the loading speed is set to Vs, and it is shown that the desired speed is obtained at time Tp. Now, considering that the floating head slider support arm 110 is operated along such a profile, the acceleration acting on the floating head slider support arm 110, that is, the transmission force profile from the actuator, is Corresponds to a differentiated profile. Therefore, profile a results in sinusoidal force transmission, and profile b
It is easily understood that the force is transmitted in a reverse step manner. Considering this as a forcing force on the floating head slider support, the response at the floating head slider section is determined by the forcing force and the transfer characteristics of the floating head slider support.

As explained above, the floating head slider support can be considered as a system consisting of a spring system consisting of a load spring and a gimbal spring, and a mass system of the floating head slider. Therefore, it generally has a primary resonant frequency on the order of several hundred hertz. Therefore, depending on the frequency characteristics of the driving force transmitted by the floating head slider support support arm 110, its characteristic component may be increased by the transmission characteristics of the floating head slider support, and the floating head slider portion may exhibit a large vibration state. be.

Further considering this point, it is clear that profile b in FIG. 2 has an extremely wide range of frequency components in the frequency domain, since it is a time function of an inverse step-like force. Therefore, when operating under profile b, vibrations of the spring mass system occur in the floating head slider, and stable loading speed control may not be possible. On the other hand, profile a basically has only a single frequency component because the external force is defined as a time function that is basically single or close to it in the acceleration region. Therefore, by setting the natural frequency to a value other than the primary resonance of the floating head slider support system, it is possible to realize an operation in which vibrations of the system are suppressed.

FIG. 3 is a diagram showing the state of displacement leading to loading of the floating head slider when driven with each of the profiles shown in FIG. 2. Here, displacement is Figure 1
This refers to the distance h between the air lubricating surface 5 of the floating head slider 2 and the surface of the magnetic disk medium 1, which is also shown in FIG. it is,
The figure shows the process of gradually reducing the amount from h when the floating head slider 2 is completely unloaded to reach the flying height hs of the floating head slider 2 that performs normal operation as a magnetic disk device. There is. In FIG. 3, profile n corresponds to profile a in FIG. 2, and profile m corresponds to profile b. As is clear from FIG. 3, profile n is a basic profile, and a substantially constant speed is achieved just before time h1, and the loading speed is controlled to be constant. On the other hand, in profile m, a high frequency caused by the natural vibration characteristics of the floating head slider support is superimposed on the basic waveform, and the loading speed is
It is the sum of the fundamental waveform component and the vibration component. here,
Considering that the loading speed, which greatly affects the reliability of the head-medium interface, is controlled within a nearly constant range, if the displacement h is constant and the inherent characteristics of the floating head slider support are constant, the profile m Even in a state like this, the speed is controlled in a sense, and therefore,
There is no problem. However, in reality, it is impossible to make the distance h and the unique characteristics uniform in a large number of floating head mechanisms. In this regard, by selecting n as the operating profile of the floating head slider and setting its frequency characteristics using the drive function generator 10, taking into account the natural vibration characteristics of the floating head slider support system, it is possible to sufficiently cope with system variations. , it is possible to realize speed control of the floating head slider operation for stable loading without being affected by vibration disturbance of the slider spring system. Up to this point, the explanation has been given using the loading operation as an example, but the unloading operation can also be realized by tracing the loading operation in reverse, and the effect is the same as that of the loading operation.

FIG. 4 is a partial sectional view for explaining a second embodiment of the floating head load/unload mechanism of the present invention. FIG. 4 explains the operational definition of the present invention regarding a load-unload method known as a so-called ramp load method. Note that the electrical connection of the drive function generator to the actuator (not shown) is the same as in FIG. 1. In this system, the load spring 3 shown in cross section slides down or up the slope while a part of the load spring 3 is in contact with the ramp 15, thereby realizing loading and unloading. At that time,
The moving speed of the floating head slider support including the load spring 3 has a speed component along the ramp 15 of speed Vr at its center of gravity CG. However, the speed component that can actually be controlled is the seek speed component indicated by Vs in FIG.
By simply controlling s, Vp corresponding to the loading speed can be controlled. Therefore, in this case, it goes without saying that by simply defining the driving function corresponding to profile a in FIG. 2 as Vs, qualitatively similar effects to those in the first example can be obtained.

[0024]

Effects of the Invention By using the floating head loading/unloading mechanism of the present invention, it is extremely unlikely to be affected by manufacturing variations in the floating head slider support, and C
It is possible to avoid the problems of friction and wear and adhesion between the floating head slider and the magnetic disk medium related to SS, thereby minimizing the generation of dust in the atmosphere of the magnetic disk device, and greatly reducing the risk of head crash. can be reduced to

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of a floating head load-unload mechanism according to the present invention.

FIG. 2 is a diagram illustrating the operating speed of a floating head slider support.

FIG. 3 is a diagram illustrating the movement of a floating head slider.

FIG. 4 is a partial sectional view showing another embodiment of the floating head loading/unloading mechanism according to the present invention.

[Explanation of symbols]

1 Magnetic disk medium 2 Floating head slider 3 Load spring 4 Gimbal spring 5 Air lubricated surface 6 Spacer 9 Actuator driver 10 Drive function generator

Claims (1)

[Claims] 1. A floating head slider, a gimbal spring consisting of a tongue-shaped leaf spring that supports the floating head slider, and a plate to which the gimbal spring is joined at one end and at the same time applies an appropriate weight to the floating head slider. A floating head that loads or unloads the floating head slider onto or from a magnetic disk medium surface by a floating head slider support made of a spring-like load spring, and a movement of the floating head slider support by a load-unload actuator or a positioner actuator. A load-unload mechanism,
During a loading or unloading operation, a velocity component in the normal direction to the magnetic disk medium surface of the floating head slider driven by the load-unload actuator or the positioner actuator is
A drive function generator that generates a drive pattern as a partial function expanded on the time axis of a sine wave that is considered to be approximately a single frequency in the frequency domain, and that is electrically connected to the load-unload actuator or the positioner actuator. A floating head load-unload mechanism featuring.