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Slide unit, fluid dynamic pressure bearing and motor employed the same

A technology for sliding parts and sliding surfaces, which is applied in sliding contact bearings, rotating bearings, bearings, etc., can solve problems such as increased spark discharge, achieve the effects of increasing rotation speed, suppressing short-term grinding, and reducing frictional resistance

Inactive Publication Date: 2008-11-12
KYOCERA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0034] However, in recent years, opportunities to use fluid dynamic pressure bearings have increased even in mobile environments. Due to the vibration applied to the equipment, the rotating rotating part contacts the fixed part momentarily, and when the rotation is stably separated after frictional electrification, The chance of spark discharge continues to increase, and its countermeasures are required

Method used

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  • Slide unit, fluid dynamic pressure bearing and motor employed the same
  • Slide unit, fluid dynamic pressure bearing and motor employed the same
  • Slide unit, fluid dynamic pressure bearing and motor employed the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～7、 comparative example 1～6

[0168] Contains the following three types of particles and MgO and ZrO as sintering aids 2 , Y 2 o 3 and Yb 2 o 3 The components of are modulated to form Figure 1 ~ Figure 4 The shaft 2, the sleeve 3 and the flange 4 of the fluid dynamic pressure bearing 1 shown are raw materials of ceramics.

[0169] Al 2 o 3 Particles: average particle size 0.5μm, purity over 99%

[0170] TiC particles with large particle size: average particle size 3μm, purity over 98%

[0171] TiC particles with small particle size: average particle size 0.6μm, purity over 98%

[0172] The mixing ratio of two kinds of TiC particles, according to the mass W of the large particle size TiC particles 1 and the mass W of small TiC particles 2 ratio of W 1 / W 2 Say, 50 / 50.

[0173] Al 2 o 3 The mixing ratio of the particles and the two types of TiC particles was adjusted so that the total content (mass %) of the two types of TiC particles in the total amount of the three types of particles became...

Embodiment 8、9

[0217] The same shaft 2 and sliding surfaces 2a, 3c of the sleeve 3 as those manufactured in Examples 1 and 7 were mirror-finished, and then put into the drum together with water and abrasive (white corundum) and rotated for 1 hour. Using an atomic force microscope (AFM), the surface shape of the sliding surfaces 2a, 3c subjected to the above-mentioned treatment was measured, and it was found that, as Figure 9 As shown, TiC grains 41, 42, from Al 2 o 3 The defined sliding surfaces 2 a , 3 c protrude from the surface of the crystal grain 40 . The surface shape of the sliding surfaces 2a and 3c before the above treatment was also measured, and as a result, protrusion of TiC crystal grains was not found.

[0218] For the above-mentioned Examples 8 and 9, the same test as above was carried out. The gap G formed between the opposing sliding surfaces 2a, 3c of the shaft 2 and the sleeve 3 23 The interval is set at 4 μm or more and less than 5 μm. Table 4 shows the results of E...

Embodiment 10～12、 comparative example 14

[0223] Assemble the same shaft 2 and flange 4 as those produced in Example 1, and adjust the TiC content and set the difference from the volume intrinsic resistance value of the above-mentioned shaft 2 and flange 4 to the values ​​shown in Table 5. The sleeve 3 made of ceramics with a small volume intrinsic resistance value constitutes the fluid dynamic pressure bearing 1 . Gap G formed between the opposing sliding surfaces 2a, 3c of the shaft 2 and the sleeve 3 23 The interval was set at 2 μm. In addition, the spin test (I) was carried out. Table 5 shows the results of Example 1 together with the aforementioned Examples and Comparative Examples.

[0224] table 5

[0225] Volume intrinsic resistance value

[0226] It can be seen from the table that if the difference between the volume intrinsic resistance values ​​of the ceramics forming the shaft 2 and the ceramics forming the sleeve 3 is set at 10 5 Ω cm or less, the occurrence of spark discharge can be relia...

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Abstract

The present invention provides sliding members respectively having sliding surfaces opposed to each other for creating dynamic pressure in a fluid, in which the sliding surfaces are formed of ceramics containing crystal grains of Al2O3, crystal grains of TiC contained in the crystal grains of Al2O3, and crystal grains of TiC existing independently of the crystal grains of Al2O3, and having a TiC content of 5 to 20 mass % in the total amount of Al2O3 and TiC, and the respective volume resistivity values R1 and R2 of the ceramics forming the sliding surfaces are within a range simultaneously satisfying equations (1) to (3) to prevent spark discharges from being induced between the sliding surfaces, and a fluid dynamic pressure bearing and a motor to which the configuration is applied: 10<6 >Omega.cmOmega.cm (1); 10<6 >Omega.cmOmega.cm (2) ; |R1-R2|<=10<5 >Omega.cm (3).

Description

technical field [0001] The present invention relates to a sliding member using fluid dynamic pressure for lubrication, which is used in computer peripheral equipment, various industrial machines, machine tools, etc., a fluid dynamic pressure bearing having a structure using the sliding member, and a fluid dynamic pressure bearing incorporating the fluid dynamic pressure. Bearings for the motor. Background technique [0002] In recent years, bearings on the motors of hard disk drives (HDDs) or polygonal reflectors constituting the laser scanning system of laser printers (LBP) have replaced the conventional combined rotating bodies (balls, rollers, etc.) and lubricants (lubricating oil, grease, etc.), hydrodynamic bearings that use fluid dynamic pressure for lubrication are often used. [0003] Figure 11 It is a cross-sectional view showing a state in which the rotating member 1R is rotated in an example of the fluid dynamic pressure bearing 101 . Figure 12 yes means Figu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F16C17/10F16C33/24C04B35/10H02K5/16H02K7/08
Inventor 氏田润草野一英三垣俊二
Owner KYOCERA CORP