JPS63251626A - Plastic bearing - Google Patents

Abstract

PURPOSE:To increase the surface rigidity of the captioned bearing by manufacturing the bearing from a composite which mainly consists of plastics and which is compounded with ceramic particles. CONSTITUTION:A plastic bearing is made up of a composite in which ceramic particles having a mean particle diameter of 100mum or smaller are mixed into a synthetic resin in 50-80wt.% Since the mean particle diameter of the ceramic particles is 100mum or smaller, the surface of the bearing is smooth. In addition, the hardness of the particles consisting of ceramic is high enough, and the compounding ratio is kept at as high as 50-80wt.%, which is a maximum that can be held by the synthetic resin. Therefore, the surface rigidity of the bearing can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a plastic bearing that has excellent wear resistance and is used in spindles of audio equipment and the like.

[Conventional technology]

The main types of resins used in plastic bearings are so-called engineering plastics such as Chikini polyacetal, polyamide, and polyphenylene sulfide resin. It is used in the form of a composite material mixed with lubricating substances.

[Problem that the invention seeks to solve]

Plastic bearings using this type of resin are widely used in drive parts of copying machines and other equipment, but among these, plastic bearings used in spindles of video tape recorders, compact disc players, etc. However, very strict wear resistance is required. In other words, the wear resistance I required for conventional plastic bearings was approximately several microns at a friction of 71, but
Plastic bearings for the above-mentioned spindles are required to have a value of several microns or less.

However, conventional plastic bearings could not satisfy this value, especially in the thrust bearing portion.

The reason for this can be seen by closely observing the initial wear of plastic bearings used in conventional thrust bearings (the period when t9 wear is extremely small).

One is that the surface of the plastic bearing undergoes peeling in units of molecules due to contact with the phase Y material, and the other is that the surface of the plastic bearing lacks rigidity.
This is because the bearing is elastically deformed by the high surface pressure generated by the thrust load 1, which expands the contact area between the bearing and the mating material, increases the sliding speed, and accelerates wear.

The present invention was made to solve these conventional problems, and aims to provide a plastic bearing that has high surface rigidity and prevents wear from progressing during initial wear.

[Means for solving problems]

The plastic bearing according to the present invention is made of a composition in which 50 to 80% by weight of ceramic particles having an average particle size of 100 μm or more are blended into a synthetic resin.

The synthetic resin mentioned above may be either a thermal i+7 plastic resin or a thermosetting resin, but it is preferable to use a thermosetting resin such as an epoxy resin or a phenol resin, which has a high surface rigidity.

Although the shape of the ceramic particles is not particularly limited, it is preferably close to spherical. This is because if the particles are round, the orientation will be poor and it will not be possible to improve the molding precision, but if the particles are spherical, the precision will be better.

The reason why the average particle diameter of the ceramic particles is set to 100 μm or less is because if the diameter exceeds 100 μm, the surface of the plastic bearing will become uneven, and the convex portions will protrude from the lubricating oil film and damage the mating material that comes into sliding contact. It is. The ceramic particles are made of silica, alumina, silicon nitride,
It may be made of a material with high hardness such as glass, and is not particularly limited.

The reason why the amount of ceramic grains Y- added to the synthetic resin is limited to 50% to 80% is because if it is less than 50%, the rigidity of the surface of the plastic bearing will decrease and the This is because when used in spindles, it is not possible to obtain sufficient wear resistance. This can be determined from the results of the wear resistance test (FIG. 2) of a bearing having the composition of Comparative Example 5 shown in Table 1.゛Also, 80%
If this value is exceeded, the force of the synthetic resin to hold the ceramic particles will be low, and the ceramic particles will peel off from the synthetic resin and disperse into the lubricating oil film. This is because this damages or wears out the mating material.

[Effect]

Since the above-mentioned ceramic particles have an average particle size of 100 μm or more, the surface of the bearing becomes smooth. In addition, the material constituting the particles is ceramic and has high hardness.
0 to 80 jQ 1%, which is sufficient to hold the synthetic resin, increases the surface rigidity of the bearing.

For this reason, it is thought that the surface of the bearing is less likely to be deformed by the thrust load, the contact area with the mating material is not expanded, and wear does not progress in the initial wear state.

〔Example〕

Based on epoxy resin, 70% silica particles with an average particle size of 11 μm are added as a compounding material (see Table 1).
A disk-shaped bearing with an outer diameter of 10Il+oφ and a thickness of 2mm was molded.

1! A thrust wear resistance test was conducted using the prepared PlusDeck bearing as the thrust lF4 bearing of the durability test spindle shown in FIG.

The shaft 2, which is the mating material, has a roughness Ra = 0.05 ~
0.07, quenched 5US420J2, tip radius 3R
It is. The test conditions are as follows. That is, F
a-300 gf, the temperature was 40° C., the rotational speed of the shaft 2 was 490 r, p, m, and the lubricating oil was mineral oil grease. In the figure, 3 is a housing, 4 is an oil-impregnated metal bearing, 5 is a load plate, and 6 is a pulley for driving the shaft 2.

(Comparative Examples 1 to 4) As Comparative Examples 1 to 4, bearings having the compositions shown in Table 1 were molded in the same manner as in the examples, and 1! A thrust wear resistance test was conducted using the bearing as shown in FIG. 1 as a thrust bearing for the spindle shown in FIG. Note that Comparative Examples 1 to 3 are based on thermosetting resin, and Comparative Example 4 is a typical example of a conventional plastic bearing based on thermoplastic resin. The shape, properties, and test conditions of the shaft 2 are the same as in the example.

(Comparative Example 5) Comparative Example 5 is an example in which the composition is the same as that of the example, but the amount of silica grains as a compounding material is less than 50%. This comparative example is a test example conducted in order to set the limit of the blending ratio of ceramic grains t in the present invention. The spindle, test conditions, etc. used in the test were the same as in the example.

FIG. 2 shows the test results of the above Examples and Comparative Examples 1 to 5.

As is clear from the figure, the plastic bearing of the actual hh example has a wear depth of 1 to 3 μm even after 1000 hours of operation. This wear Fil is at least one b+- part or less compared to the plastic bearings of Comparative Examples 1 to 4.

The reason why wear;

(Effects of the Invention) As explained above, according to the present invention, a composition is based on a synthetic resin and contains ceramic particles having an average particle size of 100 μm or less at a ratio of 50 to 80 lQ jd%. Since it is made of plastic, it is possible to obtain a plastic bearing that has high surface rigidity and prevents wear from progressing during initial wear.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a plastic bearing according to an embodiment of the present invention and a spindle of a comparative example subjected to a thrust wear resistance test, and FIG. 2 is a graph showing the results of the thrust wear resistance test. 1-------Thrust bearing 2...Shaft 3...Housing 4-----1 Oil-impregnated metal bearing 5---Load plate Applicant 11 16 [Stocks] Company Figure 1 Figure 2

Claims (1)

[Claims] A plastic bearing made of a composition in which 50 to 80% by weight of ceramic particles with an average particle size of 100 μm or less are blended into a synthetic resin.