JPS59131567A - Abrasion resistant sliding material - 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 The present invention provides a wear-resistant sliding material. More specifically, the present invention relates to a wear-resistant sliding material that can be used even at high humidity without lubrication.

Graphite bearings have conventionally been used as sliding bearings that can be used in high humidity conditions without lubrication, and have been used as sliding bearings. Graphite bearings have excellent wear resistance and self-lubricating properties, so they can be used up to high temperatures.However, their large porosity and therefore poor mechanical strength is a major drawback. do.

Therefore, in order to reinforce this mechanical strength, the pores are impregnated with a thermosetting resin or a metal with a relatively high melting point. When impregnated with resin or metal, it expands, decomposes, melts, and leaches under high temperature and pressure. Due to decomposition, heat resistance and humidity are below 200℃, and the difference in thermal expansion coefficient between graphite and resin causes blistering phenomenon (
fire, phenomenon) occurs. However, if it is impregnated with metal, it will deteriorate its durability, corrosion resistance, and its sliding properties will deteriorate, causing a seizure phenomenon.

In addition, bronze-based and iron-based gold
J/J of graphite, molybdenum disulfide, etc. using Z metallurgy method
-G roller) The solid lubricant dispersion type smoky metal g bearing is also popular, and compared to the graphite bearing G, the mechanical stability is improved, and it is possible to achieve high A without lubrication. Although it can be used up to 494, since the base material is metal, it has poor chemical resistance and corrosion resistance, and it not only has poor wear resistance at high temperatures, but also causes the inner diameter of the bearing to shrink due to oxidation expansion, affecting the bearing clearance. There are some shortcomings.

In addition, plastic bearings and sintered oil-impregnated bearings are also used, but these are based on the heat resistance temperature of the material itself or
Considering the service life of the impregnated lubricating oil, etc., the operating temperature is approximately 80 to 120℃, excluding fluororesin bearings.
Alternatively, it is actually used at a temperature of 11 or lower. In addition, fluororesin bearings do not only have a high heat resistance temperature of approximately 250°C, but also have characteristics such as a low coefficient of friction and excellent chemical resistance, but on the other hand, they are soft and prone to creep. It has its drawbacks. In particular, the greater the surface pressure or the higher the temperature, the greater the creep, deformation, and problems such as flow. Furthermore, the coefficient of thermal expansion is on the order of 10, which is an order of magnitude larger than that of metals, and because of such coefficient of thermal expansion and creep, it is often used practically at temperatures below 200°C.

The present invention provides a wear-resistant sliding material that does not exhibit any of these drawbacks, and the friction-resistant sliding material of the present invention made of a glassy carbon material and a solid lubricant graphite can be Self-lubricating properties are maintained up to about 450°C in the atmosphere and up to about 2500°C in an inert gas atmosphere.

Glassy carbon materials are produced by carbonizing a cured molded product of furan resin, phenol resin, or a mixture thereof in an inert atmosphere at a high temperature, generally at a temperature of about 1000°C or higher, and if necessary. It can be obtained by further graphitizing. In addition, a carbon precursor material having an oxygen functional group derived from a pitch with an adjusted hydrogen/carbon atomic ratio (H/C) is powder-molded, then similarly fired and carbonized, and if necessary, this is further added to graphite. It can be obtained by converting

Graphitization treatment, which is performed as necessary, is performed by subjecting the fired material to high temperature treatment for a long time at about 2000 to 300° C. using a graphitization furnace. However, the glassy carbon material is a non-graphitizable material, and even if such high-temperature heat treatment is performed, graphitization will progress only slightly, but this graphitization will cause the glassy carbon material to have poor lubricity. When a carbon material causes contact between gold and M, developing a graphite structure improves lubricity, although the hardness slightly decreases.

These glassy carbon materials have a light specific gravity like graphite, but are very hard and strong, have excellent chemical resistance and corrosion resistance, and have a heat resistance of about 450°C in the air and in an inert gas atmosphere. It is a new carbon material with a high temperature of about 2500℃ and an extremely high specific strength, and is mainly used in crucibles, boats,
It has been traditionally used for heaters, electrodes, etc.

Graphite as a solid lubricant blended into such a glassy carbon material has a hexagonal crystal structure and tends to be sheared in a direction parallel to the layers, so it has self-lubricating JIJ and It is an inexpensive material. Graphite is used in a blending ratio of about 20 to 70% by weight of the glassy carbon material. If the proportion is less than this, the coefficient of friction will increase due to lack of lubricity, while if the proportion is greater than this, the mechanical strength of the sliding material will be insufficient.

The sliding material is manufactured by forming a homogeneous mixture of a glassy carbon material forming material and graphite into a predetermined shape, and then carbonizing this at the firing temperature of the glassy carbon material forming material. When using a cured resin molded product, since a sliding material with a thickness of only about 3 mm can be produced from a mixture with graphite alone, a carbon material such as graphite or a carbon precursor containing an oxygen functional group is generally used. It is used in the form of a coating on a molded body as a base material, which is formed from a fired product of the substance.

In this case, since the resin is impregnated into the pores of the molded body made of a base material such as a carbon material, the coating is firmly adhered to the molded body, and at the same time, the strength of the molded body itself is improved thereby. In addition, when the oxygen-functional group-containing carbon precursor substance is used as a material for forming a glassy carbon material, after powder-forming a uniformly blended powder with graphite into a predetermined shape with an arbitrary thickness under pressure at room temperature, Firing and carbonization are performed. The sliding material manufactured in this way has sufficient mechanical strength because it is made of glassy carbon material, but in order to further improve it, it is necessary to add carbon fiber, It is also possible to form a carbon-carbon composite material by blending graphite fibers or the like.

The sliding material according to the present invention is extremely hard and has high strength.
The base material is a heat-resistant glassy carbon material.
Since it contains graphite as a solid lubricant, it has excellent wear resistance and maintains its lubricity up to high temperatures of about 450°C in the air and about 2500°C in an inert gas atmosphere. Furthermore, it has excellent chemical resistance and corrosion resistance, and is stable even in high-temperature forming chemicals, so it does not have the drawbacks of poor chemical resistance and corrosion resistance or oxidation that were found in conventional metal-impregnated graphite bearings and graphite-dispersed sintered metal bearings. There is no such phenomenon as expansion. Furthermore, even at high temperatures, it does not tend to leap as seen in fluororesin bearings, and its coefficient of thermal expansion is slightly lower than that of iron, making it easy to control the bearing clearance.

Next, the present invention will be explained with reference to examples.

Example 1 A powder mixture of pitch coke with a particle size of 10μ or less and binder pitch in a weight ratio of 7:3 was heated at room temperature under a compacting pressure of 3.
The powder was molded into a disk shape with a diameter of 5 Qmm and a thickness of 1011171 mm at 000 r.

On the other hand, 50 parts by weight of natural graphite (particle size 10 to 20 μm) was uniformly dispersed in 50 parts by weight of liquid furan-based resin, and this dispersion was applied several times to the surface of the disc-shaped powder compact with a brush. Each time, curing was repeated to form a film there. Then, the coating surface was polished to make it flat, and the temperature was raised to 1000° C. at a rate of 10° C./hr in an inert gas atmosphere to perform firing and carbonization.

A coating approximately 1 mm thick was formed on the surface of the disk and was made of a very hard glassy carbon material containing 50% by weight graphite.

Regarding this, the frontal friction and wear characteristics were investigated using a precious wood type friction and wear tester (thrust type tester). In the friction and wear test, a cylindrical mating material (54 mm) with an inner diameter of 20 blades and an outer diameter of 25.671111 mm was placed on this disc test piece (surface roughness: 3 s).
5a carburizing and quenching, hardness HRC51-54, surface roughness ISX
The test piece was mounted so that the sliding area 27) was fixed, and the test piece was rotated under the following conditions.

Lubrication: None Rotation speed: Constant above 40mA (Rotation speed: 559 rpm)
Surface pressure: 0.5.3.0.5.5, S, O ~ (cumulative load) Operating time: Maintained at each surface pressure for 8 hours (32 hours in total) Ambient air temperature: Normally wet Comparative example 1 Induction from pitch The powder compact containing only the oxygen-functional group-containing carbon precursor material was fired and carbonized by increasing the temperature to 1000 °C at a temperature increase rate of 20 °C/hr.
The friction and wear characteristics of S) were similarly investigated.

Furthermore, for comparison, the M abrasion characteristics were similarly investigated for a graphite-dispersed bronze-based sintered metal bearing material (Comparative Example 2) 3 and a graphite material (Comparative Example 3), both of which had a surface roughness of 38. Ta.

The values of the friction coefficient and the temperature rise with respect to the cumulative load (and its converted PV value) are both shown in the graph of FIG. Further, the results of measuring the amount of wear of each test piece and its counterpart material at the end of 32 hours of operation are shown in Table 1 below.

Table 1 Example 1' 0.002 0.4 Comparative Example 1
0. -017 3.51/ 2 0
．． 029 2・6// 3 0.012
2.3 From the results shown in Figure 1 and Table 1, the sliding material according to the present invention has a smaller coefficient of friction, lower temperature rise, and lower wear amount than other materials, and can be used satisfactorily as a sliding material. I understand.

Example 2 In Comparative Example 1, natural graphite (particle size 1o~20μ) 50
Powder compaction of a disc body containing % by weight and sintering thereof,
Carbonization was carried out similarly.

This was heated to 300℃ using a precious wood type friction and wear tester (thrust type tester) equipped with a high-frequency heating device, and 'i'f
, an abrasion test was conducted. The test conditions were a rotation speed of 5
The procedure was the same as in Example 1, except that the pressure was changed to m1 minute, the surface pressure was changed to 8 to 100 hours, and the operating time was changed to 100 hours.

A similar test was conducted on material S1 of each of the ratios of Na:13 and Mae 5.

The amount of 1 near H wear is shown in the graph in Figure 2, and 100
The friction coefficients of each test piece immediately before the end of the time run are shown in Table 2 below.

Table 2 Example 2 0.19 Comparative Example 1033 tt 20.36 〃3 0.28 From the results in Figure 2 and Table 2, even under the high humidity condition of 300°C, the sliding gain according to the present invention is It can be seen that the amount of wear is significantly lower than that of the material, and the coefficient of friction is also small and stable. In addition, when observing the sliding surface after the friction and wear test, other materials had clear sliding marks and severe unevenness, but the sliding material of the present invention has a smooth sliding surface. This confirms that a good I-scan condition was maintained during sliding.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the values of the friction coefficient and temperature rise with respect to the cumulative load (and its converted pv value) in the friction and wear test. Further, FIG. 2 is a graph showing the value of the amount of wear against the operating time in the friction and wear test. Representative Patent Attorney Yoshi IB Toshio Figure 1 0 100, 200
300 4oo p1
4 (Q/l-1ψ) 2nd figure number change Rtl (time)

Claims (1)

[Claims] 1. Glassy charcoal=? A wear-resistant sliding material made of a lubricant and a solid lubricant. 2 Special 8'IM containing about 20 to 70% graphite
Abrasion-resistant sliding material N'1゜3 described in item 1 of the scope of interest Patent jj;
Wear-resistant sliding material 'p'FQ4 described in item or item 2 Patent f applied to a bearing sample as a sliding surface of a sliding bearing
tl'7 desired range jl-r (1st, 1st term or 2nd term, 1st term) Wear-resistant tC sliding material.