JPH04261491A - Damping material and production thereof and buffer vibration damping mechanism using the same material - Google Patents

Abstract

PURPOSE:To obtain a damping material capable of preventing occurrence of evaporating ingredients exerting bad influence on operation of a precision machine, freely controlling ratio of viscosity and electricity and obtaining always stabilized damping effects and buffer vibration damping mechanism and magnetic disk using the above-mentioned damping material. CONSTITUTION:A damping material 15 is constituted by packing space among particles of hard ceramic fine particles 21 of silicon carbide, etc., having <=1mum average particle size with a high molecular fluorine based oil or grease 22 such as perfluoropolyether. Then a buffer vibration damping mechanism obtained by packing the above-mentioned damping material in fine gaps formed by each fitting piston parts 5a and 5b in cylinder-like holes 14a and 14b is used for a head-retaining part 4 of magnetic disk and coupling part of a driving part 6.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a damping material suitable for precision machines such as magnetic disk drives that require high cleanliness against minute dust or gas, a method for producing the same, and a method using the same. Regarding a damping vibration damping mechanism.

0002

2. Description of the Related Art Conventionally, in magnetic disk drives, in order to rapidly record and reproduce information on tracks formed on a magnetic disk, a magnetic head is moved to a target track position on the surface of a magnetic disk at high speed. need to be moved. However, when the magnetic head moves at high speed to the target track, vibrations may occur in the magnetic head, and these vibrations are an obstacle to positioning the magnetic head accurately and at high speed with respect to the target track. .

In order to prevent problems caused by such vibrations of the magnetic head, conventionally, as described in Japanese Patent Application Laid-Open No. 63-257967, a weight or a spring has been installed on the surface of the carriage opposite to the surface on which the arm is mounted. Some were equipped with a vibration absorption mechanism consisting of parts and vibration isolating parts. In this conventional vibration absorbing mechanism, a leaf spring is used as the spring component, and a vibration isolating rubber is used as the vibration isolating component. Furthermore, another method for suppressing vibrations of the magnetic head is to use a friction damper that utilizes frictional force.

[0004]Furthermore, fine dust from outside the device may enter the inside of the device, oil mist may be generated inside the device due to a rise in temperature inside the device, and metal powder may be generated inside the device due to friction of movable parts inside the device. It may occur. When these dust, oil mist, and metal powder adhere to the magnetic head, a problem arises in that recording and reproducing performance deteriorates. In addition, during recording and playback, the flying posture of the magnetic head relative to the magnetic disk surface is disturbed and the magnetic head collides with the magnetic disk surface (head crash), which can damage the magnetic disk surface and cause defects to form on the magnetic disk surface. There is a problem in that the information recorded on the track is lost.

[0005]

[Problem to be solved by the invention] The above-mentioned Japanese Patent Application Laid-Open No. 63-25
In the technology described in Publication No. 7967, low-molecular organic substances contained in the rubber used in vibration-proof parts become gaseous and fill the inside of the device as the temperature inside the device rises and over time, causing damage to the magnetic head. There was a problem in that it adhered and caused a head crash. Furthermore, since rubber has both viscous and elastic properties, it is difficult to select a rubber with the most suitable properties for the device, and there is a problem in that its elasticity transmits vibrations.

[0006] Furthermore, in the method using the friction damper described above, since frictional force is unstable compared to viscosity, there is a problem that it is difficult to always obtain a constant effect. Furthermore, since frictional force is used, the generation of dust such as metal powder cannot be avoided, and it is necessary to separately provide a sealing mechanism to prevent the generated dust such as metal powder from leaking to the outside.

A first object of the present invention is to provide a damping material suitable for use in precision machinery, which prevents the generation of evaporated components that adversely affect the operation of precision machinery.

A second object is to provide a damping material whose ratio of viscosity and elasticity can be freely adjusted.

A third object is to provide a method for producing a damping material having the above-mentioned properties.

A fourth object is to provide a damping and damping mechanism that can effectively absorb vibrations and shocks using a damping material having the above characteristics.

[0011] The fifth purpose is to prevent the vibrations generated when the magnetic head is positioned at a desired position on the magnetic disk at high speed from being transmitted to the magnetic head. An object of the present invention is to provide a magnetic disk device using a damping material having the above characteristics as a damping material of a damping damping mechanism provided between the two.

0012

[Means for Solving the Problems] In order to achieve the above object, the damping material according to the present invention is made by impregnating fine particles of metal or ceramic with a polymeric high-viscosity fluorine-based oil or grease.

[0013] In order to provide such a damping material, the air present between the metal or ceramic particles is forcibly evacuated to impregnate the particles with high-molecular, high-viscosity fluorine-based oil or grease. It is something that

Furthermore, the damping mechanism according to the present invention includes a damping material for precision machinery in which fine particles of metal or ceramic are impregnated with polymeric high-viscosity fluorine-based oil or grease, and a substantially cylindrical damping material with an opening on one side. The damping material is constructed by providing a cylinder member having a cylindrical shape and a substantially cylindrical piston member that fits into the cylinder member, and filling the space formed when the cylinder member and the piston member are fitted with the damping material.

[0015] In the above-mentioned shock absorbing damping mechanism, the piston member has a shape having a head that fits into the cylinder member with a small gap formed therebetween, and a neck having a diameter smaller than the diameter of the head. , so as to always obtain a stable damping effect.

In the above-mentioned damping damping mechanism, a recess is provided around the piston member, and an O-ring is fitted into the recess to completely prevent the oil component from evaporating from the damping material. .

Further, in the present invention, in a magnetic disk device having an actuator section including a magnetic disk on which information is magnetically recorded and a magnetic head for recording or reproducing information on the magnetic disk, the damping The material is used as a damping material for the shock absorbing damping mechanism of the actuator section.

[0018]

[Operation] The damping material according to the present invention can be produced by selecting the material, size, etc. of the metal or ceramic fine particles, and selecting the type, amount, etc. of the fluorine-based oil or grease. Properties such as viscosity and elasticity can be freely set.

Furthermore, since the method for manufacturing a damping material for precision machinery according to the present invention is carried out under high vacuum conditions, most of the elastic air bubbles existing between the metal or ceramic fine particles can be removed, and almost only the viscosity can be removed. damping materials with almost no elasticity can be obtained.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing an example of an actuator section of a magnetic disk device using the damping material of the present invention in a damping damping mechanism.

The magnetic heads 2 arranged facing the recording surfaces of the plurality of magnetic disks 1 are each supported by a support arm member 3.
Supported by The end portion of the support arm member 3 that supports the magnetic head 2 that does not support the magnetic head 2 is attached to the head holding portion 4 .

The head holding portion 4 has piston members 5a, 5.
b is attached, and these piston members 5a, 5b
is a cylindrical hole 14a formed in the guide/drive section 6.
, 14b, respectively, with a small gap between them.

A damping material 15 having a structure as shown in FIG. 3 is filled in the minute gaps formed by fitting the piston members 5a and 5b into the cylindrical holes 14a and 14b, respectively. .

A spring holder 13 is attached to the head holding section 4, and a preload spring 12 is disposed between the spring holder 13 and the guide/drive section 6. Due to this preload spring 12, a force is always applied to the head holding portion 4 and the piston members 5a, 5b in a direction that pulls them in the direction of the guide/drive portion 6.

The guide/drive section 6 is provided with a plurality of guide rollers 7 that can roll on the surface of a guide rail 8. A drive coil 11 is attached to the opposite side of the guide/drive unit 6 to the surface facing the magnetic disk 1, and the drive coil 11, magnet 10, and magnetic circuit 9 form a voice coil motor. And drive coil 11
By energizing, an electromagnetic driving force is generated, and the guide roller 7 rolls on the surface of the guide rail 8, thereby moving the actuator section so as to position the magnetic head 2 at a predetermined position on a desired track. .

In the actuator section of the magnetic disk drive configured as described above, the magnetic head 2 is positioned and driven to a desired track on the magnetic disk 1 using the electromagnetic driving force generated by energizing the driving coil 11. do. At this time, the electromagnetic driving force generated by the driving coil 11 may locally elastically deform each part of the guide/drive section 6 and generate high frequency vibrations.

Furthermore, when the guide roller 7 rolls on the surface of the guide rail 8 and the actuator section moves to a desired position, there may be problems such as surface roughness of the contact surface between the guide roller 7 and the guide rail 8. Vibration may occur.

These vibrations are transmitted to the guide/drive section 6,
Vibration components of various modes other than the driving force act on the guide/drive section 6.

However, in the magnetic disk drive of this embodiment, the damping material 15 is filled in the minute gap formed by the cylindrical holes 14a, 14b and the piston members 5a, 5b, so that the above-mentioned problem occurs. This high frequency vibration is absorbed by the damping material 15 and is prevented from being transmitted from the guide/drive section 6 to the head holding section 4.

FIG. 2 shows the piston members 5a and 5a shown in FIG.
5b maintains a small gap between the cylindrical holes 14a and 14.
FIG. 6 is a diagram showing another embodiment of the damping part fitted in b.

In FIG. 2, the piston member 5a' (5b
') consists of a head part 18, a neck part 17 and a body part 19. Neck 1
7 is located between the head 18 and the body 19, and has a smaller diameter than the head 18 and the body 19.

[0033]The diameter of the body portion 19 is the diameter of the cylindrical hole 14.
a (14b), and the diameter of the head portion 18 is formed to be slightly smaller than the diameter of the body portion 19.

However, in the present invention, the head portion 18 and the body portion 19 may each have the same diameter and approximately the same size as the diameter of the cylindrical hole 14a (14b).

Furthermore, in the embodiment shown in FIG. 2, a damping material 15 is filled in the space formed by the head 18 and the cylindrical hole 14a (14b).

Further, a recess 20 is provided around the body 19, and an O-ring 16 is fitted into the recess 20 to improve airtightness.

Next, the damping material 15 will be explained using FIG. 3.

The damping material 15 is made of a polymeric fluorinated oil such as perfluoropolyether having a molecular structure of [Chemical formula 1] between the hard ceramic fine particles 21 such as silicon carbide having an average particle size of 1 μm or less, or It is filled with grease 22.

[0039]

[Chemical formula 1]

[0040] In the damping material 15 having such a structure,
The ceramic fine particles 21 and polymeric fluorine-based oil or grease 22, which are its constituent elements, both have the characteristic of extremely low compressibility, and the polymeric fluorine-based oil or grease 22 has the characteristic of high viscosity. have. Therefore, this damping material 15 has almost only viscosity and almost no elasticity.
becomes.

The perfluoropolyether used here as the polymeric fluorinated oil or grease 22 has a low vapor pressure of 10~8 mmHg at room temperature and hardly evaporates even in vacuum, so it is suitable as a lubricant for bearings for artificial satellites. used in Therefore, the amount of evaporation is almost negligible under normal atmosphere, and there is little possibility of contaminating the equipment even if it is used inside a precision machine.

In the damping section shown in FIG.
The head 18 is connected to the cylindrical hole 14a (14b).
) Damping material 1 filled in the space formed by
When 5 is pressed, the damping material 15 is inserted into the cylindrical hole 14a.
(14b) and the head 18 of the piston member 5a'(5b')
It passes through a narrow clearance S with the neck part 17 and protrudes into a wide clearance part of the neck part 17. The damping material 15 that has passed through the narrow clearance S accumulates in the wide clearance portion of the neck portion 17.

Since the damping material 15 does not produce viscous resistance in the wide clearance portion of the neck portion 17, a certain damping effect can be obtained even if the piston member 5a'(5b') moves with a large stroke.

As described above, a damping effect can be obtained by the viscous resistance during flow when the damping material 15 passes through the narrow clearance S in the length range L of the head 18. At this time, since the damping material 15 has almost only viscosity and almost no elasticity as described above, it can absorb the vibrations from the guide/drive section 6 without transmitting them to the magnetic head 2.

FIG. 4 shows the damping characteristics of the damping section shown in FIG. 2. In the graph shown in FIG. 4, the vertical axis represents the pushing force of the piston 5a'(5b'), and the horizontal axis represents the pushing displacement amount.

As the piston 5a'(5b') is pushed in, the pushing force increases, but this pushing force is saturated at a certain value. This is a cylindrical hole 14a (14
b) shows a state in which the narrow clearance S between the head 18 of the piston member 5a'(5b') is completely filled with the damping material 15. Thereafter, even if the pushing amount is increased, no increase in pushing force is observed, and a constant resistance force is always obtained.

Furthermore, if the operation of pushing the piston member 5a'(5b') is interrupted after the resistance force becomes constant, the position of the piston member 5a'(5b') remains unchanged, and only the pushing force becomes zero. . This is because the damping material 15 has almost only viscosity and almost no elasticity. When the pushing of the piston member 5a'(5b') is resumed, the pushing force returns to the level before the interruption of pushing, and this state is maintained.

This damping characteristic is similar to that of the piston member 5a' (5
b'), the shape and dimensions of the cylindrical hole 14a (14b), the size of the clearance S, and the piston member 5a' (5b).
') can be freely set by selecting the pushing speed and the damping material 15.

Next, a method for manufacturing the damping material 15 will be explained using FIG. 5.

The oil-impregnated container 23 contains a polymeric fluorine-based oil or grease 22 . Further, the particle holding container 24 contains ceramic fine particles 21 . A particle holding container 24 containing ceramic fine particles 21 is submerged in an oil-impregnated container 23 containing polymeric fluorine-based oil or grease 22.

Furthermore, the oil-impregnated container 23 is a hermetically sealed container with one end connected to the vacuum pump 25 and an exhaust pipe 26 connected to the other end.

[0052] With the device configured in this way, the vacuum pump 2
When the air pressure inside the oil-impregnated container 23 is lowered to below atmospheric pressure by forcibly exhausting air 27 in step 5, the air 27 existing between the ceramic fine particles 21 that have entered the particle holding container 24 is removed.
is discharged to the outside of the oil-impregnated container 23, and high-molecular fluorine-based oil or grease 22 is filled between the particles in place of the discharged air 27.

By doing this, it is possible to obtain the damping material 15 in which the air 27 existing between the ceramic fine particles 21 is completely replaced with the polymeric fluorine-based oil or grease 22.

In this embodiment, the same effect can be obtained by using ceramic particles such as silicon nitride, zirconia, alumina, or diamond particles instead of silicon carbide as the ceramic particles 21.

In this embodiment, if elastic metal particles or the like are used, a damping material having some elasticity can be obtained. Examples of metal particles that can be used here include chemically stable metals such as stainless steel, nickel, chromium, aluminum, gold, and silver. On the other hand, metals that rust and corrode, such as iron, are not suitable.

In particular, when a ceramic material containing components such as silicon carbide, silicon nitride, zirconia, and alumina is used, it is possible to obtain a damping material having almost only viscosity because of its extremely high hardness and rigidity. Moreover, when metal powder having elasticity is used, a damping material having both viscosity and elasticity can be obtained.

Furthermore, in this embodiment, when selecting the oil or grease, a high viscosity effect can be obtained by using a particularly highly viscous polymer oil or grease as the base oil.

For example, fluorine-based polymer oil or grease has the characteristic that it is difficult to evaporate to the extent that it is normally used for bearing lubrication in a vacuum environment. The damping material prevents the oil content from evaporating and does not contaminate the inside of precision machinery that uses this damping material. Fluorine-based oil is used as a lubricant for the surface of the magnetic disk in magnetic disk drives, so if you select an oil or grease that is similar to this oil, the information stored on the magnetic disk will be protected against trace amounts of evaporated components. is unlikely to be destroyed.

In this embodiment, the damping material is a chemically stable solid material such as metal or ceramic, that is, a solid material that does not cause a chemical reaction in the general atmosphere, and a chemically stable oil or oil that is originally liquid. Since grease is used, the molecular structure is less likely to change over time, unlike rubber, so stable viscoelastic properties can always be obtained.

The damping material in this example has almost no compressibility due to its material composition. In addition, like clay, it is easy to change its shape freely, and its shape is less likely to be restored.

Furthermore, the method for producing the damping material in this example involves impregnating fluorinated oil or grease into the minute voids existing between fine metal or ceramic particles under high vacuum conditions. Alternatively, the density of metal or ceramic fine particles contained in the grease can be easily increased, and the fluidity, liquid retention, etc. of the damping material can be freely set.

The damping damping mechanism of this embodiment fills the above-mentioned damping material into the space formed by fitting the piston member into the cylinder member, and prevents the cylinder member from moving relative to the piston member in the thrust direction. A high damping effect can be obtained due to the viscous resistance during shear deformation of the damping material due to the damping material, or the viscous resistance when the damping material flows through the narrow gap formed between the cylinder member and the piston member.

[0063] In the above-mentioned shock absorbing damping mechanism, by providing a sealing means such as an O-ring on the piston member, it is possible to prevent a small amount of fluorine oil or grease from evaporating.

[0064]

Effects of the Invention The damping material according to the present invention is composed of a fluorine-based oil or grease that has high molecular weight and high viscosity and is extremely difficult to evaporate, and fine particles of metal or ceramic that mainly have elasticity or rigidity. It prevents the generation of evaporative components that adversely affect precision machines such as disk devices, and has almost only viscosity or can freely adjust the ratio of viscosity and elasticity, making it possible to always obtain a stable damping effect. There is an effect that it can be done.

Furthermore, since the damping material according to the present invention is manufactured under conditions where the pressure is lowered to below atmospheric pressure, the air existing between the ceramic fine particles can be completely replaced with polymeric fluorine-based oil or grease. This has the effect of eliminating elasticity due to air existing between particles.

The shock absorbing damping mechanism according to the present invention using the damping material manufactured by the above method has the advantage of being able to effectively absorb vibrations and shocks of the device.

[0067] The magnetic disk drive using the above-mentioned damping vibration damping mechanism does not generate dust inside the drive.
It is possible to prevent phenomena such as head crashes that adversely affect the device, and furthermore, it is possible to precisely position the target track.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of an actuator section of a magnetic disk device using the damping material of the present invention in a damping damping mechanism.

FIG. 2 is a diagram showing another embodiment of the damping portion shown in FIG. 1;

FIG. 3 is a diagram for explaining the structure of the damping material of the present invention.

FIG. 4 is a diagram showing the damping characteristics of the damping section shown in FIG. 2;

FIG. 5 is a diagram for explaining a method for producing a damping material of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Magnetic disk, 2... Magnetic head, 3... Support arm member, 4... Head holding part, 5... Piston member, 6... Guide
Drive unit, 7... Guide roller, 8... Guide rail, 9... Magnetic circuit, 10... Magnet, 11... Drive coil, 12
...Preload spring, 13...Spring holder, 14...Cylindrical hole,
15...damping material, 16...〇ring, 17...neck, 1
8...Head, 19...Body, 20...Recess, 21...Ceramic fine particles, 22...Polymer fluorine oil or grease,
23... Oil impregnated container, 24... Particle holding container, 25... Vacuum pump, 26... Exhaust piping.

Claims (6)

[Claims] 1. A damping material characterized in that fine particles of metal or ceramic are impregnated with a polymeric, high-viscosity fluorine-based oil or grease. [Claim 2] Fine metal or ceramic particles placed in a particle holding container are immersed in a high-molecular, high-viscosity fluorinated oil or grease placed in a sealed container, and the air in the sealed container is forcibly evacuated. A method for producing a damping material, which comprises impregnating high-molecular and high-viscosity fluorine-based oil or grease between fine metal or ceramic particles by bringing the inside of the closed container close to a vacuum state. 3. A damping material in which fine particles of metal or ceramic are impregnated with high molecular weight, high viscosity fluorine-based oil or grease, a cylinder member that is approximately cylindrical and has an opening on one side, and a damping material that is fitted into the cylinder member. A damping damping mechanism characterized in that a substantially cylindrical piston member is provided, and a space formed when the cylinder member and the piston member are fitted is filled with the damping material. 4. A recess is provided on the circumferential surface of the piston member,
4. The shock absorbing damping mechanism according to claim 3, wherein an O-ring is fitted into said recess. 5. The piston member has a head that fits into the cylinder member with a small gap therebetween, and a neck having a diameter smaller than the diameter of the head. The buffer damping mechanism according to claim 3 or claim 4. 6. A magnetic disk on which information is magnetically recorded, a magnetic head for recording or reproducing information on the magnetic disk, a support arm member for supporting the magnetic head, and a supporting arm member for supporting the magnetic head. In a magnetic disk drive having a head holding section to which a supported support arm member is attached, and a guide/drive section for positioning the magnetic head at a desired position on the magnetic disk, the head holding section and the guide/drive section may be connected to each other. A damping vibration damping mechanism is provided between the magnetic heads to prevent vibrations generated in the guide/drive section from being transmitted to the magnetic head.
2. A magnetic disk device using a damping material according to claim 1, wherein the damping material is used as a damping material of the damping damping mechanism.