JP2009180376A - Sliding bearing, and working machine connecting device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding bearing having improved seizure resistance and wear resistance under high bearing pressure and low speed sliding states while maintaining characteristics stably for a long time without lowering the strength of a sintered sliding material, and to provide a working machine connecting device using the same. <P>SOLUTION: A lubricant mixture formed by dispersing lubrication oil into wax in terms of liquid is filled into a pore of a Cu alloy. The lubricant mixture is formed so that the lubricating oil containing a 80-99.5 wt% extreme-pressure additive is dispersed in the solid wax of 0.5 wt% or higher and lower than 20 wt% at room temperature in terms of liquid. Its dropping point is 20°C or higher and lower than 60°C, and the viscosity of the lubricating oil in the lubricant mixture at 40°C is lower than 220 cSt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention uses a sliding bearing that is used under a lubrication condition with extremely poor surface pressure, low-speed sliding, and rocking, such as a working machine bush used in a working machine coupling device of a construction machine, and the sliding bearing. The present invention relates to a work machine coupling device.

  Conventionally, oil-impregnated sliding bearings in which lubricating oil is contained in pores in a Cu-based or Fe-based porous sintered alloy are often used as sliding bearings that are used for long-term greasing intervals or without lubrication. Further, the lubricating oil impregnated in these oil-impregnated bearings is adjusted to an appropriate viscosity according to sliding conditions such as surface pressure and sliding speed in which the oil-impregnated bearing is used. On the other hand, the selection of porous Cu-based sintered alloy or Fe-based sintered alloy is determined according to conditions such as oil lubrication, sliding speed, sliding surface pressure, etc. In conditions, bronze-based oil-impregnated bearings are often used, and in high surface pressure and low-speed sliding conditions, Fe-C, Fe-Cu, and Fe-C-Cu-based oil-impregnated bearings are used (see Non-Patent Document 1).

  In Non-Patent Document 1, in selecting a lubricating oil to be used for an oil-impregnated bearing, a high-viscosity lubricating oil is selected for low speed and high load, and conversely for high speed and light load. It is appropriate to select a low-viscosity lubricating oil. Generally, the proper oil for sintered bearings causes a hydraulic escape phenomenon compared to non-porous sliding bearings. It is described that it is close.

  The biggest problems with construction machine work machine coupling devices are that the sliding speed is extremely slow and the lubricity is very poor. For example, the viscosity of the lubricating oil impregnated in the sliding bearing having a sliding speed in the range of 1 to 3 m / min in this work machine coupling device is the kinematic viscosity (cSt) at 50 ° C. according to the above-mentioned selection criteria for the lubricating oil. It is taught that ISOVG400 to ISOVG900 are preferable when the lubricating oil is 100 to 800 cSt, the lubricating oil equivalent to ISOVG100 to ISOVG900 has an appropriate viscosity, and is used under high surface pressure. In addition, it is a known fact that various types of additives such as extreme pressure additives are contained in the lubricating oil for sliding bearings having seizure resistance and wear resistance.

Patent Document 1 discloses that 240 to 1500 cSt of lubricating oil is applied to an iron-based sintered oil-impregnated bearing used for sliding conditions with a high surface pressure of 600 kgf / cm ² or more and a sliding speed of 1.2 to 3 m / min. Impregnated plain bearings are disclosed.

  Furthermore, in Patent Document 2, a lubricating composition having a dropping point of 60 ° C. or higher in a semi-solid state or a solid state at normal temperature contains martensite in an iron-carbon alloy matrix, and at least one of copper particles and copper alloy particles. It is disclosed that a sliding bearing filled in pores of an iron-based sintered alloy in which is dispersed becomes a favorable sliding bearing in a surface pressure state of 30 MPa or more.

  In addition, sliding bearings are also used in which graphite pieces, which are solid lubricants, are regularly arranged on high-strength brass or bronze bearings, and the graphite pieces are impregnated with lubricating oil (for example, manufactured by Oiles Kogyo Co., Ltd.). “500SP”)

  On the other hand, as a sintered alloy for oil-impregnated bearings for high surface pressure, in Patent Literature 3, Cu particles or Cu alloy particles are dispersed in an iron-carbon alloy base where martensite is present, and the Cu content is 7 to 30% by weight, 5-30% by weight of alloy particles having a specific composition as a harder phase than the iron-carbon alloy base are dispersed, and the porosity is 8-30% by volume. A wear-resistant sintered alloy for oil-impregnated bearings is disclosed.

Japanese Patent No. 2832800 JP-A-10-246230 JP-A-8-109450

Edited by Japan Powder Metallurgy Industry Association, “Sintered Machine Parts-Design and Manufacturing-”, Technical Shoin Co., Ltd., October 20, 1987, P327-341

  It is well known that fluid lubrication is rarely achieved in actual oil-impregnated plain bearings, and most of them slide under boundary lubrication conditions. In addition, due to the escape of hydraulic pressure through the pores in the sintered material, the film thickness of the lubricating oil on the sliding surface becomes less than the surface roughness of the bearing surface, and in many cases, solid friction (adhesion) is reduced. Because of the sliding conditions involved, the lubrication condition is easily controlled by the chemical function (composition) of the lubricant and the function (composition and structure) of the bearing material. It is well known that it becomes about .1. FIG. 5 shows the application range of an oil-impregnated sliding bearing that is used for general purposes (see P337 of Non-Patent Document 1, “FIG. 6.19 Application Example of Sintered Bearing”).

As described above, the sliding conditions in the case of applying the sliding bearing to the construction machine working machine coupling device are often such that the surface pressure is 300 kgf / cm ² or more and the sliding speed is 0.1 to ² m / min. For example, in a connecting device provided in a hydraulic cylinder portion of a work machine boom, which will be described later, the surface pressure is 700 kgf / cm ² , and the average sliding speed by rocking is 0.1 m / min. When this is applied to FIG. 5, it is clear that it is necessary to develop a higher-load oil-impregnated slide bearing that is not at least in the range of conventional light-load oil-impregnated slide bearings such as home appliances.

  It is also clear that development of oil-impregnated sliding bearings used in this type of work machine coupling device requires development from the viewpoints of both lubricating oil and sintered sliding material.

  Furthermore, considering recent environmental problems, it is also desired not to add Pb contained in a large amount in the Fe-based or Cu-based sliding material.

By the way, in the said patent document 1, kinematic viscosity in 40 degreeC is used for the iron-type sintered oil-impregnated bearing used for the sliding condition of the sliding speed of 1.2-3 m / min with the high surface pressure of 600 kgf / cm < ² > or more. A sliding bearing impregnated with 240 to 1500 cSt of lubricating oil is disclosed, but this sliding bearing is not sufficient as a sliding bearing used in a lower sliding speed state like the bearing of the working machine boom cylinder. There is a point.

  Further, Patent Document 2 contains an oil and wax containing at least one of an extreme pressure additive and solid lubricant particles in a semi-solid state or a solid state at room temperature, and a lubricating composition having a dropping point of 60 ° C. or higher. The surface pressure state of the sliding bearing in which the pores of the iron-based sintered alloy containing martensite in the iron-carbon alloy matrix and in which at least one of the copper particles and the copper alloy particles is dispersed is 30 MPa or more However, in a mode of extremely low surface pressure and extremely low sliding speed like the bearing of the working machine boom cylinder, a semi-solid state having a dropping point of 60 ° C. or more is disclosed. This lubricant composition has a problem that the lubricity is not sufficiently improved.

  In Patent Document 2, the wax in the lubricating composition is paraffin wax, microcrystalline wax, carnauba wax, rice wax, candelilla wax, beeswax, montan wax, polyethylene wax, preferably paraffin. The wax is a microcrystalline wax, and the oil content in the lubricating composition is an industrial lubricating oil containing an extreme pressure additive. The wax content is 20 to 40% by weight, and 0.5% in the wax. It is disclosed to contain at least one of up to 1.5% by weight of extreme pressure additive and 1.5 to 2.5% by weight of solid lubricant particles, but the working machine is operated at a low temperature of 0 ° C. or lower. In this case, the dynamic viscosity is extremely high, and lubricity due to the partial lubricating oil film as described above can be expected. , From becoming easily caused remarkable adhesion with a metal contact friction, there is a problem that it is impossible to exhibit sufficient functions as a sliding bearing of the work machine connecting device.

  In addition, as long as adhesion wear on the sliding surface proceeds during sliding for a long time, the pores in the sliding material on the sliding surface at a higher surface pressure are blocked by plastic deformation. This is a lubricating composition with a high dropping point because of the clogging of pores on the sliding surface due to the formation of sludge or varnish due to condensation of lubricating oil, decomposition of extreme pressure additive and decomposition of wax. It is clear that high-viscosity lubricating oil has insufficient supply capability to the sliding surface, so that sufficient high surface pressure resistance and durability as an oil-impregnated sintered bearing for a work machine cannot be obtained.

  In addition, even when the pores of a porous oil-impregnated sintered bearing are filled with semi-solid grease to which a solid lubricant is added, the solid lubricant may block the porous capillaries and reduce the oil impregnation effect. From the fact that there are many, it is clear that it is desirable to avoid the addition of a solid lubricant when using a lubricating composition having a long refueling interval and a high dropping point.

  On the other hand, in the wear-resistant sintered alloy for oil-impregnated bearings disclosed in Patent Document 3, (1) C: 0.6 to 1.7 wt%, Cr as alloy particles dispersed in the iron-carbon alloy matrix : Fe-based alloy particles (high-speed tool steel (high-speed) powder particles) containing 3 to 5 wt%, W: 1 to 20 wt%, V: 0.5 to 6 wt%, (2) C: 0. Fe containing 6 to 1.7 wt%, Cr: 3 to 5 wt%, W: 1 to 20 wt%, V: 0.5 to 6 wt%, at least one of Mo or Co: 20 wt% or less Base alloy particles (high-speed tool steel (high-speed) powder particles containing Mo or Co), (3) Mo: Mo-Fe alloy (ferromolybdenum) containing 55 to 70% by weight, (4) Cr: 5 to 15 Co-base alloy containing 1% by weight, Mo: 20 to 40% by weight, and Si: 1 to 5% by weight (heat resistant and wear resistant alloy for overlay spraying (Patent name: Kobamet manufactured by Cabot Co., Ltd.) In addition, in Patent Document 3, the plastic deformation of the base is reduced by the dispersion of the hard alloy particles, and the load applied to the base alloy during sliding sliding. It is disclosed that a sintered oil-impregnated bearing alloy exhibiting excellent wear resistance can be obtained.

  However, in an Fe-C-Cu oil-impregnated bearing material used under normal boundary lubrication, when a Cu or Cu alloy powder is sintered, large outflow holes formed in the sintered body have a long time. The seizure resistance can be improved by preventing the lubrication hole from being blocked on the sliding surface and, in addition, the martensite structure has a high yield strength under higher surface pressure. It is clear from the fact that the sliding surface is used after being subjected to hardening heat treatment such as induction quenching tempering and carburizing quenching tempering, and the marten containing Fe—C-7 to 30 wt% Cu disclosed in Patent Document 2 is used. It is clear that the oil-impregnated sintered sliding material of the structure including the site is not sufficient.

  Moreover, in what is disclosed in Patent Document 2, it is clear that dispersing hard alloy particles such as high-speed powder is effective in improving seizure resistance and wear resistance. There is a limit to the amount of hard alloy particles to be added (5 to 30% by weight), and in order to reduce the burden on the base alloy during sliding, the load is concentrated on the hard alloy particles. There is a problem that the effect of improving the property is not sufficient.

In order to further improve this point, it is widely known that a solid lubricant such as MoS ₂ , WS ₂ , BN, graphite or the like is contained in the sintered sliding material at 3% by weight or less. However, when many of these solid lubricants are added, there is a problem that the strength of the sintered sliding material is significantly deteriorated. In addition, these solid lubricants are generally added on the lubricant side. However, this solid lubricant easily closes the pores on the sliding surface, and as described above, the solid lubricant is added. When the agent is filled in the pores of the oil-impregnated sintered bearing, the amount of solid lubricant added in the lubricating composition filled in the pores of the oil-impregnated sintered bearing is optimized so as not to block the porous capillary tube. There is a problem of having to.

In addition, in a normal work machine coupling device, work machine pins arranged on the inner diameter part of the slide bearing need to support a high stress bending load, so heat treatment such as induction hardening, carburizing, gas soft nitriding, nitriding, etc. is performed. Since the sliding surface hardness of the working machine pin sliding with the working machine sliding bearing is hardened to Vickers hardness H _V = 450 or more, for example, as disclosed in Patent Documents 1 to 3, from the standpoint of conformability, when adjusted to the hardness of Vickers hardness H _{V =} approximately 450 to 750 containing the martensite has a problem of easily galling occurred actuation initial. In particular, for oil-impregnated sintered plain bearings that are filled with a lubricating composition that is difficult to penetrate into the sliding surface due to the high dropping point, the accumulation of local galling in the initial stage of operation leads to abnormal noise. There is a problem that it is easy.

  Furthermore, for oil-impregnated sintered bearings, the wear during use is dominated by adhesion wear, and has a structure containing harder martensite as disclosed in Patent Documents 1 to 3 above. As oil-impregnated sintered sliding bearings for iron-carbon alloy bases, harder oil-impregnated sintered bearings are desired as countermeasures against abrasive wear caused by sand and sand in parts where work machines cannot be prevented from entering from the outside. However, the oil-impregnated sintered plain bearings described in these documents have a problem that they are not always excellent in adhesive wear.

  The present invention has been made to solve such problems, and is excellent in seizure resistance and wear resistance even under high surface pressure and low speed sliding, and reduces the strength of the sintered sliding material. It is an object of the present invention to provide a sliding bearing that can stably maintain its characteristics for a long time without causing a failure, and a work machine coupling device that uses the sliding bearing.

In order to achieve the above object, the sliding bearing according to the first invention is
A sliding bearing in which pores of a Cu alloy-based porous sintered body are filled with a lubricant mixture in which a lubricating oil is liquid-dispersed in wax,
The lubricant mixture is liquid-dispersed with a lubricating oil containing 80 to 99.5 wt% extreme pressure additive in a solid wax of 0.5 wt% or more and less than 20 wt% at room temperature. The point is 20 ° C. or more and less than 60 ° C., and the viscosity of the lubricating oil in the lubricant mixture at 40 ° C. is less than 220 cSt.

  In the present invention, considering the operability at a low temperature, the lubricating oil has a pour point of −20 ° C. or less, a viscosity at 40 ° C. of 100 cSt or less, and excellent lubricity to the sliding surface. It is preferable to adopt the above (second invention).

Further, at a sliding speed of 0.1 m / min or less and a high surface pressure of about 1200 kgf / cm ² , the outermost surface is exposed to a high temperature due to local adhesion during the sliding, so that the low temperature The lubricating oil has a low kinematic viscosity at a low temperature, an excellent heat resistance, and a sliding surface in consideration of improving the lubricity on the side and the heat resistance of the lubricating oil on the high temperature side. It is preferable to use a synthetic lubricating oil that suppresses the generation of sludge that causes clogging of the pores (third invention). This synthetic lubricating oil does not have the property of losing fluidity by crystallizing wax at a low temperature like mineral oil.

  The synthetic lubricating oil is preferably composed of at least one of polyol ester, phosphate ester, polybutene, polyα olefin, polyglycol, and polyphenyl ether having excellent heat resistance (fourth invention). Ester oil and phosphate ester oil have low kinematic viscosity at low temperatures and strong chemical adsorption on metal surfaces, so they have excellent lubricity, and these synthetic oils polycondense at high temperatures to form sludge. Therefore, it is a particularly preferred synthetic lubricating oil in the present invention because it has the characteristic of lower molecular weight (polybutene and polyglycol have the property of decomposing and volatilizing at high temperatures). Further, since the phosphate ester is used as an extreme pressure additive and an antiwear additive when added to mineral oil, the synthetic lubricating oil is preferably a mixture of one or more.

  Furthermore, various additives such as antioxidants and extreme pressure additives that suppress the generation of sludge can be used in the same manner as in the case of general lubricating oils, but excessive addition tends to cause sludge formation. In particular, the addition amount of S which is likely to generate sludge does not exceed 0.2% by weight so that it can be easily applied to a copper alloy oil-impregnated sintered sliding bearing where sulfur attack is likely to occur. It is desirable that 2% by weight or less and Zn, Mg, Ca, B, and I are each 0.1% by weight or less. In addition, the amount of (S + P + Zn + Mg + Ca + B) added in the gear lubricant for missions (75W / 90) encouraged in Japan is 0.85 to 3.43% by weight, and in particular, S is often the main component. The amount of S added is preferably 0.37 to 3.1% by weight. In the present invention, the amount of (S + P + Zn + Mg + Ca + B), which is an extreme pressure additive contained in the synthetic lubricating oil, is adjusted to 0.5% by weight or less to suppress sludge generated on the sliding surface. (5th invention).

  On the other hand, the waxes constituting the mixed composition with the lubricating oil are limited to the range of 3 to 20% by weight from the viewpoint of adjusting the dropping point. As these waxes, natural wax (plant system: candelilla wax, carnauba wax, described in a reference book (written by Kenzo Fusegawa, “Property and Application of Wax”, Sachishobo, September 10, 1983)) Rice wax, animal system: beeswax, lanolin, mineral system: montan wax (brown coal)), petroleum wax (paraffin wax, microcrystalline wax), synthetic wax (polyethylene wax, sazol wax, 12 hydroxystearic acid), etc. Waxes such as derivatives of 12 hydroxystearic acid (amides, esters, metal soaps, etc.), fatty acid amides, fatty acid ketones, fatty acid amines, fatty acid imides and the like that are often used for waxes and lubricating oils can be used. In short, in the present invention, the wax is selected from among waxes such as paraffin wax, microcrystalline wax, carnauba wax, polyethylene wax, and stearic acid, lauric acid, 12 hydroxystearic acid, and oil gelling agent used in lubricants. It is preferable that it is 1 or more types (6th invention).

  It should be noted that, since plant-based and animal-based waxes tend to generate sludge, oil wax and synthetic wax are mainly used, the melting point is at least 35 ° C. and the oil-impregnating conditions in the pores of the porous sintered body Therefore, it is preferable to adjust the melting point of the wax to about 120 ° C. or less in consideration of the temperature at which oxidation of the lubricating oil easily occurs. Among the waxes, paraffin wax, low density polyethylene wax, and 12 hydroxystearic acid are low-melting waxes that do not easily generate sludge and have excellent lubricity, and are clearly preferable waxes.

  By the way, as described above, under boundary lubrication conditions involving metal contact friction, the porous metal sintered body described in Non-Patent Document 1 and the iron-carbon base sintering containing martensite described in Patent Document 2 are used. Since the body does not withstand sufficient durability and use under higher surface pressure conditions, in the seventh invention, in the first invention, the Cu alloy-based porous sintered body is at least Sn: 2 The sliding bearing contains 10 to 10% by weight and Al: 2 to 14% by weight.

The Cu alloy-based porous sintered body is a sintered sliding material for high surface pressure resistance disclosed by the present applicant in Japanese Patent Laid-Open No. 2001-271129. This sintered sliding material is an (α + β) two-phase or β-phase structure in which at least a β phase is dispersed in the sintered structure, and further, various intermetallic compounds, CaF ₂ , graphite It is characterized in that a solid lubricant or the like may be contained. In addition, in order to maintain the bearing rigidity and the pressure input when press-fitted into the work machine coupling device, the sliding material constituted by integrating the sintered sliding material with the inner diameter surface of the iron-based backing metal. Bearings are used.

The Cu-Al-Sn oil-impregnated sintered material is softer than the above-described bearing material containing martensite and has excellent compatibility with work machine pins. It becomes a very good oil-impregnated sintered sliding bearing that cannot be achieved, and an extremely excellent sliding bearing that can be used at a very low sliding speed of, for example, 0.05 m / min and under a high surface pressure of up to 1200 kgf / cm ^2. However, since expensive copper-based materials are used and the above-mentioned rigidity and pressure input (withdrawal strength) are required, it is necessary to integrate with the back metal, which is economically cheaper. Clearly, a bearing is desired.

The porous sintered body preferably contains 10% by volume or less of hard particles harder than at least the sintered base (eighth invention). In this case, the hard particles are preferably TiC, WC, V ₄ C ₃ , TiN, Si ₄ N ₃ , Al ₂ O ₃ , Mo carbide, Cr ₇ C ₃ carbide, ferromolybdenum, or ferrochrome. (13th invention). Further, as a cheaper material, in iron-carbon alloy-based sintered alloys, ceramic particles such as SiO ₂ , Al ₂ O ₃ , TiC, TiP, ZrO ₂ , and phosphorous iron have a remarkable attacking property against work machine pins. It is clear that plain bearings using Fe-C, Fe-C-Cu and Fe-C-P based sintered materials added in the range of 0.2 to 10% by volume not shown also show good sliding characteristics. is there.

  By the way, although the sliding bearing in the said 1st invention-the 9th invention normally slides with the bearing pin distribute | arranged to the internal-diameter part, the direction where it integrates with the outer peripheral surface side of a bearing pin is more. In many cases, the bearing device has the same or more functional advantages and is economically preferable. For this reason, the tenth aspect of the invention is one or more methods of spraying, infiltration joining, sintering joining, brazing, adhesion, caulking, fitting, press fitting, and screwing on the outer peripheral surface of the bearing shaft. A work machine coupling device including an integrated multilayer bearing shaft is provided.

  Further, in the work machine coupling device according to the tenth aspect of the present invention, in order to eliminate grease for a long time, an inexpensive Cu-based oil-impregnated sintered sliding bearing containing a large amount of a lubricating composition and the inner diameter side of the bush are provided. It is preferable that the working machine coupling device is a combination of the arranged multi-layer bearing shafts (multi-layer working machine pins). Further, the sliding layer integrated with the outer peripheral surface of the multilayer bearing shaft in this case is not necessarily porous, and is impregnated with a high melting point wax, resin or low melting point metal, or sealed. It is clear that increasing the density by physical means such as shot peening is preferable for forming the oil film under boundary lubrication (the 11th invention).

  As a coupling device for construction machines having extremely severe use conditions, not only a cylindrical oil-impregnated sliding bearing for a working machine but also a spherical sliding bearing or a spherical bearing shaft can be used (Twelfth Invention). Further, it is clear that this work machine connecting device can be used for a roller assembly, an equalizer, a crawler belt connecting device, and a suspension device (a thirteenth invention), all of which belong to the scope of the present invention.

In the present invention, the pores of the Cu alloy-based porous sintered body are filled with a lubricant mixture or a thermoreversible lubricating oil gel in which a lubricating oil is dispersed in a wax, thereby making it extremely slippery. Even when applied to a work machine coupling device having a low dynamic speed (0.01 to 2 m / min) and a high surface pressure (for example, 300 kgf / cm ² or more), seizure resistance and wear resistance on the sliding surface are high. It is possible to obtain a sliding bearing that is exhibited and that maintains its characteristics stably for a long period of time.

No. Metal structure photograph of A9 sintered sliding material No. Photo of metal structure of B1 sintered sliding material Cross-sectional view showing the shape of a test piece in a bearing test Graph showing coefficient of friction in rocking bearing test Graph showing the range of application of oil-impregnated plain bearings for general use

  Next, specific examples of the sliding bearing according to the present invention and the working machine coupling device using the same will be described with reference to the drawings.

Example 1 Production of Sintered Alloy
In this example, iron powder 1 (Kobe Steel Atmel 300), iron powder 2 (Kobe Steel Atmel 4600), # 100 mesh iron powder 3 (2000 series + 0.5 wt% Ti), graphite powder ( Lonza KS6), electrolytic copper powder (CE15 made by Fukuda Metals), phosphorous iron (Fe 25 wt% P) of # 250 mesh or less, Al powder, Sn powder, TiH powder, high speed steel SKH51 powder, average particle size 1.5 μm Si ₄ N ₃ powder, CaF ₂ (average particle size 55 μm), Ni powder having a particle size of 350 μm or less were used to prepare the mixed powder shown in Table 1. A weight percent organic lubricant was blended and molded into a cylindrical molded body having an inner diameter of 46 mm and a height of 50 mm with a pressure of ^{3 to} 6 ton / cm ² . Here, No. 1 shown in Table 1 is used. A1-No. The iron-based material of A10 was sintered at 1150 ° C. for 1 hr, cooled in the furnace to 950 ° C., and further rapidly cooled by N ₂ gas cooling.

  On the other hand, Table 2 shows examples of copper-based sintered alloys. No. shown in Table 2 The copper-based sintered material B1 is sintered at 960 ° C. for 1 hr and sintered and joined to the inner peripheral surface of a cylindrical steel pipe (equivalent to S50C).

  In Table 1, No. A9 and A10 are Fe-Al-Cu sintered sliding materials having excellent sliding characteristics disclosed in Japanese Patent Application Laid-Open Nos. 9-49006 and 2002-180216. B1 is a Cu—Al—Sn sintered sliding material disclosed in JP-A No. 2001-271129 and having a β phase having excellent sliding characteristics as a parent phase. 1 and FIG. A9 and No. Each representative organization of B1 is shown.

Example 2 Production of Lubricating Composition
In this example, a lubricating composition for filling the pores of the sintered material was prepared. As the lubricating oil, an industrial gear oil based on mineral oil having a kinematic viscosity at 40 ° C. of 68 to 680 cSt (ISOVG 68 to ISOVG680) and a polyol ester synthetic lubricating oil (Mobil Corporation, MJO II) are used. Paraffin wax (melting point 70 ° C., indicated as “P-wax” in Table 3), microcrystalline wax (melting point 63 ° C., indicated as “M-wax” in Table 3), 12 hydroxystearic acid (melting point 73 ° C., Table 3) A lubricating composition as shown in Table 3 was prepared using an oil gelling agent butyramide (GP1; melting point 156 ° C.).

  The amount of wax added was 1 to 40% by weight, but it was found that, for example, when paraffin wax was added in an amount of about 15% by weight or more, the dropping point was 60 ° C. or more. In addition, GP1 (oil gelling agent) has a high melting point of 156 ° C., and in order to prevent deterioration of the lubricating oil, a lubricating composition was prepared by adding a material dissolved in ethyl alcohol to the lubricating oil.

  Further, the method of filling the lubricating composition of the present example into the sintered body pores of Example 1 was a method of immersing the previous sintered body in the liquid lubricating composition heated to 120 degrees under reduced pressure. .

(Example 3; bearing test)
FIG. 3 shows the shape of the bearing test piece used in this example. In this bearing test piece, the surface roughness of the sliding surface is about 2 to 5 μm except for the sintered holes, and the shaft for the bearing test is induction-hardened and tempered with a surface layer of S50C carbon steel (160 ) And the surface hardness was adjusted to be HRC56, and the surface roughness was finished to 1 to 3 μm or less by grinding.

The bearing tester, a swinging test swing angle 10 ° and 160 °, the surface pressure is boosted every 50 kgf / cm ² after repeating oscillating number 2000 cycles to 1300 kgf / cm ^2, friction at that time The front pressure of the surface pressure at which the coefficient rapidly increased to 0.3 or more was evaluated as the seizing limit surface pressure. The average sliding speed at the low swing angle is 0.05 m / min, and the average slip speed at the high swing angle is 0.8 m / min.

  The evaluation results are collectively shown in Table 4 (low swing angle) and Table 5 (high swing angle).

  From these tables, the dropping point of the lubricating composition L4 is about 65 ° C., and the lubricating composition L5 is only for industrial gear oil having a kinematic viscosity of 460 cSt and filled with these lubricating compositions. In comparison with the above, filling with other lubricating compositions adjusted to around 40 ° C. drastically improves the seizure limit surface pressure, and in particular, a lubricating composition L8 using a polyol ester synthetic lubricating oil (drop point 39 ° C.). ) Was found to be effective in improving the critical surface pressure. Further, the lubricating composition L8 is better than the lubricating composition L6 using turbine oil having substantially the same kinematic viscosity of 32 cSt. This is because a synthetic oil with less sludge generation is used as the lubricating oil. It can be seen that this is an improvement effect due to the fact that P was 0.22 wt% as an extreme pressure additive and antiwear agent and no other extreme pressure additive was added.

  In addition, the oil gelling agent, which is an amide derivative of the lubricating compositions L10 and L11, is an appropriate amount of 0.5 to 2.0% by weight, and the addition thereof further reduces the seizure resistance improving effect. Sliding material No. When the lubricating composition for the copper-based material of B1 is used, the improvement effect is lowered, but this is clearly considered to involve corrosion and sludge generation problems due to amide decomposition products.

Further, when evaluating the seizure resistance according to the sintered sliding material, the dispersion effect in the structure of the Cu particles is hardly confirmed from the comparison between A1 * and A6 *, and A1 * and A2 *, A3, A4. From these comparisons, it is recognized that seizure resistance is improved by the dispersion of Fe3P (phosphide) and Si ₄ N _{3 in} the sintered body structure. Further, from A5 and A8, TiC precipitation dispersion during sintering, and from A7, high-speed tool steel powder (SKH51: Mo carbide, W carbide, V carbide is dispersed by about 20% by volume or less) is dispersed. Although improvement in seizure resistance is confirmed, it can be seen that it is preferable to disperse about 2% by volume of harder ceramic particles from an economical viewpoint.

  Table 5 shows the seizure limit surface pressure at a high rocking angle. Compared with the results in Table 4, an improvement in seizure resistance is observed by increasing the average slip speed. This is because the establishment of the oil film formation during the boundary lubrication described above has become high. For example, FIG. 4 shows the friction coefficient at the high swing angle and the low swing angle when the A9 material is filled with the L8 lubricating composition. The friction coefficient at the high swing angle is clearly reduced. I understand that. FIG. 4 shows the friction coefficient of the oil-impregnated bearing in which the A7 * material is filled with the L4 lubricating composition. However, it is clear that a sufficient lubrication state is not obtained even at a high swing angle. From the viewpoint of ensuring lubricity by the lubricating composition, the work viscosity on the low temperature side and the work at a lower sliding speed is set so that the kinematic viscosity of the lubricating oil is at least 100 cSt or less, and the dropping point as the lubricating composition is set. It can be seen that the temperature should be lower than 60 ° C., more preferably 45 ° C. or lower. This means that the amount of microcrystalline wax and paraffin wax added to the lubricating oil should be less than 20% by weight, more preferably 15% by weight or less, and the drop point should be 2% by weight or more at 20 ° C. Yes.

  Further, since the sintered sliding material exhibits excellent seizure resistance, it normally slides with the bearing pin disposed on the inner diameter portion thereof, but is integrated with the outer peripheral side of the bearing pin. In many cases, the bearing device has equal or more functional advantages and is economically preferable. For this reason, the above-mentioned sliding bearing is integrated with the outer peripheral surface of the bearing pin by one or more methods of spraying, infiltration joining, sintering joining, brazing, adhesion, caulking, fitting, press fitting, and screwing. It is clear that a work machine coupling device having excellent seizure resistance can be obtained. It is preferable to form a thermal spray coating including pores by spraying a sliding material such as A9, A10, A11 or the like on the outer peripheral surface of the working machine pin.

Claims (13)

A sliding bearing in which pores of a Cu alloy-based porous sintered body are filled with a lubricant mixture in which a lubricating oil is liquid-dispersed in wax,
The lubricant mixture is liquid-dispersed with a lubricating oil containing 80 to 99.5 wt% extreme pressure additive in a solid wax of 0.5 wt% or more and less than 20 wt% at room temperature. A sliding bearing characterized in that the point is 20 ° C. or higher and lower than 60 ° C., and the viscosity of the lubricating oil in the lubricant mixture at 40 ° C. is lower than 220 cSt.   The sliding bearing according to claim 1, wherein the lubricating oil has a pour point of −20 ° C. or less and a viscosity at 40 ° C. of 100 cSt or less.   The sliding bearing according to claim 2, wherein the lubricating oil is a synthetic lubricating oil that suppresses generation of sludge that causes clogging of pores on a sliding surface.   The sliding bearing according to claim 3, wherein the synthetic lubricating oil is one or more of a polyol ester, a phosphate ester, a polybutene, a poly α-olefin, a polyglycol, and a polyphenyl ether.   The sliding bearing according to claim 3 or 4, wherein the extreme pressure additive contained in the synthetic lubricating oil is adjusted to 0.5 wt% or less to suppress sludge generated on the sliding surface.   The wax is at least one of waxes such as paraffin wax, microcrystalline wax, carnauba wax, polyethylene wax, and stearic acid, lauric acid, 12 hydroxystearic acid, and oil gelling agent used in lubricants. Item 6. The plain bearing according to any one of Items 1 to 5. The sliding bearing according to claim 1, wherein the Cu alloy-based porous sintered body contains at least Sn: 2 to 10 wt% and Al: 2 to 14 wt%. The plain bearing according to any one of claims 1 to 7, wherein the porous sintered body contains at least 10% by volume of hard particles harder than the sintered body. The hard particle is any one of TiC, WC, V ₄ C ₃ , TiN, Si ₄ N ₃ , Al ₂ O ₃ , Mo carbide, Cr ₇ C ₃ carbide, ferromolybdenum, and ferrochrome. Plain bearing. The sliding bearing according to any one of claims 1 to 9 is one or more of spraying, infiltration joining, sintering joining, brazing, adhesion, caulking, fitting, press fitting, and screwing to the outer peripheral surface of the bearing shaft. A work machine coupling device using a slide bearing comprising a multi-layer bearing shaft integrated by the above method. A sliding layer is integrated with the outer peripheral surface of the multilayer bearing shaft, and this sliding layer is impregnated with a high melting point wax, resin or low melting point metal, or sealed with physical means such as shot peening or the like. The working machine coupling device using the plain bearing according to claim 10, wherein the density is increased. The work implement coupling device using a slide bearing according to claim 10 or 11, wherein any one of a cylindrical oil-impregnated slide bearing for a work implement, a spherical slide bearing, or a spherical bearing shaft is used. A work machine coupling device using a sliding bearing according to any one of claims 10 to 12, which is used in a roller assembly, an equalizer, a crawler belt coupling device, and a suspension device.

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