JPS6242983B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an aluminum alloy bearing, and more specifically, to an improvement of a tin-containing aluminum alloy bearing used as a bearing for an internal combustion engine. The above aluminum-based alloys containing tin are generally used as bearings by being pressure-welded to a backing steel plate, but in order to increase the adhesive strength between the bearing alloy and the backing steel plate, it is essential to anneal the alloy after pressure welding. Generally, this annealing is performed for a long time at a temperature below the temperature at which Al--Fe intermetallic compounds are formed. However, when tin-containing aluminum alloys are exposed to high temperatures during the above-mentioned annealing, the aluminum crystal grains and tin crystallized substances become coarse in the alloy structure, reducing the high-temperature hardness and fatigue strength of the tin-containing aluminum alloys. There was a drawback of doing so. Therefore, in order to eliminate the above-mentioned drawbacks of tin-containing aluminum bearing alloys, bearing alloys containing additive elements are also used, such as 3.5 to 4.5% Sn.
−3.5~4.5%Si−0.7~1.3%Cu−Remaining Al, 4~8%
Sn-1~2%Si-0.1~2%Cu-0.1~1%Ni-Remaining
Al, 3-40% Sn-0.1-5%Pb-0.2-2%Cu-
0.1~3%Sb-0.2~3%Si-0.01~1%Ti-Remaining
Al, 15~30% Sn-0.5~2% Cu-remaining Al, and 1~
23%Sn-1.5~9%Pb-0.3~3%Cu-1~8%
Tin-containing aluminum-based bearing alloys (hereinafter referred to as multi-component bearing alloys) such as Si-residue Al were used. However, in recent years, internal combustion engines for automobiles have been required to be smaller and have higher output, and as it has become necessary to install blow-by gas reduction devices to purify exhaust gas, the usage conditions for internal combustion engine bearings have changed. It has become worse than before. In other words, as bearings in recent years have become smaller and used under higher loads and higher temperatures than before, conventional multi-component bearing alloys are prone to fatigue failure and abnormal wear, which is one of the causes of troubles in automobile internal combustion engines. I was getting used to it. Fatigue phenomena in metal materials generally occur when the material is used for a long period of time, but in modern internal combustion engines, bearings can break due to fatigue even when high-load operation continues for a relatively short period of time. sometimes happened.
This is because the lubricating oil in the internal combustion engine becomes hot during high-load operation, and for example, the temperature of the lubricating oil in the oil pan reaches 130 to 150°C. It is predicted that the bearing alloys will be sliding at considerably high temperatures, and as a result, the high-temperature hardness of conventional multi-component bearing alloys will rapidly decrease, and tin will melt or move, which is the cause of the decrease in fatigue strength. The inventor of the present application believes that this has become the case. The applicant of the present invention proposed an aluminum alloy containing 2.5 to 25% tin, 0.5 to 8% zinc, and 0.1 to less than 1.0 chromium by weight percentage in Japanese Patent Application No. 1985-851. The applicant of this application is Tokugansho.
No. 55-852, by weight percentages 2.5 to 25% tin, 0.5 to 8% zinc and 1 to 7% silicon, chromium, manganese, nickel, iron, zirconium, molybdenum, cobalt, tungsten, titanium, antimony, niobium, vanadium,
An aluminum-based alloy containing at least one element selected from the group consisting of cerium, barium, and calcium, with the balance substantially consisting of aluminum has also been proposed. In these aluminum alloys, silicon, chromium, manganese, etc. are dispersed in the matrix as extremely fine hard crystallized substances, and mainly have the effect of preventing the coarsening of tin particles, and most of the zinc is dispersed in the matrix. The solid solution strengthens the matrix, thereby improving the fatigue strength and high temperature hardness of the alloy. The bearing performance of these aluminum-based alloys is improved by the synergistic effect of both matrix reinforcement and reinforcement by fine dispersion compared to the case of either single action. As one measure of bearing performance, there is the concept of conformability, which in the above patent application is based on the fact that there is always a film of lubricating oil between the bearing and the shaft, depending on the machining accuracy of the shaft, which is the mating material of the bearing. This refers to the property of a bearing in which the surface of the bearing is partially scraped off or worn out by the shaft during the early stage of use, so that the two can come into contact with each other in a state where the soft tin particles It is understood that this provides excellent familiarity. The above-mentioned approach to compatibility is an established concept in the industry, and the idea of imparting compatibility to bearings using soft tin particles is in line with the conventional thinking in the industry. It can be said that it is an extension of that. Regarding the effects of chromium, silicon, etc.,
These particles are viewed from the perspective of preventing the coarsening of tin particles, and there is no technical idea that particles such as chromium, silicon, etc. directly improve compatibility, but indirectly by controlling the shape of soft tin particles. It can be said that the description of the above patent application is consistent with the technical idea of improving the conformability of tin-containing aluminum alloys and the technical means described below. The present inventor conducted detailed research on the bearing performance of tin-containing aluminum alloys, and found that bearing performance, particularly conformability and seizure resistance, can be dramatically improved using technical ideas and means that are completely different from conventional thinking. They discovered this and completed the present invention. As described in detail later, this technical means is the control of the size of hard particles in tin-containing aluminum alloys, but in Si-Al binary alloys, hard particles precipitate or crystallize (hereinafter referred to as crystallization for convenience). It is a well-known fact that silicon particles are distributed in aluminum-based bearing alloys for internal combustion engines, and papers and patents have also been published that discuss the distribution of silicon particles in aluminum bearing alloys for internal combustion engines. According to JP-A No. 55-82756, in the production of bearing alloys, an aluminum alloy consisting of 5 to 15% silicon, 5% or less copper, 10% or less bismuth, and 1% or less lead is heated or cold. By rolling or extruding, a cross-sectional area reduction of at least 90% is obtained, so that the silicon particles in the alloy are present in the form of finely divided particles rather than in a continuous skeleton-like network. An invention that does this has been proposed. It is also stated that this bearing alloy is useful for both bearings with and without soft plating (overlay). The key points of this invention are that coarse silicon particles in a cast state are finely dispersed by rolling or the like, and annealing performed as necessary after rolling is limited to the extent that the processed structure is restored, thereby maintaining the fine morphology of the silicon particles. Furthermore, since this invention specifies that a high silicon content of about 10% is preferable, it is meaningful to finely disperse the silicon particles, which grow quite large in aluminum alloys with high silicon content. ing. However, according to the research of the present inventor, in bearing alloys for internal combustion engines used without overlay, if the content of hard particle precipitated elements such as silicon is high, the fatigue strength of the bearing decreases, especially It has been found that there is a drawback in that the load capacity is significantly reduced when the bearing slides under repeated loads from the shaft. Furthermore, for the purpose of improving bearing performance, methods such as rolling that finely disperse silicon particles do not provide satisfactory results. That is, aluminum alloys for bearings are usually manufactured by giving a cast material a predetermined size by a method such as rolling, and the silicon particles are divided by this rolling or the like. It has been found that bearing performance can be significantly improved by not only dividing these hard particles such as silicon, but also by making them coarse in some cases and controlling the number of hard particles with a certain size to a certain number. . By the way, in the above publication, an experiment was conducted on an aluminum alloy with 11% Si, and it is stated that the size of silicon fine particles is 0.0001 inch (2.5 microns) to 0.001 inch (25 microns), but the per unit area There is no mention of the number. Aluminum from SAE Technical Paper Series
Based Crankshaft Bearings for the High
Paper entitled Speed Diesel Engine (February 1981)
23-27, in Detroit) is a paper published by the same person as the above publication, in which 11% Si
The seizure load for -1% Cu-Al alloy is listed. According to this, silicon particles with a size exceeding 17 microns have a particle size of 8.7× per unit area (mm ² ).
It is explained that if there are ¹⁰⁶ particles, there will be a lot of variation in the seizure load, while if there are 0.6 x ¹⁰⁶ particles larger than 17 microns, the seizure load will be higher and less variable. This and other theoretical explanations are that the fine dispersion of hard silicon particles in the aluminum matrix contributes to improved compatibility and seize load. moreover,
In the above paper, the concept of ``compatibility'' is contradictory to the concept of ``compatibility,'' which refers to ``adaptability,'' which allows for misalignment between the crankshaft and the shaft.
(Conformability), and states that silicon-containing aluminum alloys have low conformability, so it is necessary to have an overlay. Therefore, although there has been a concept focused on silicon particle size in conventional aluminum alloy bearings, there has been no example of success in providing an aluminum alloy that can be used as a bearing without an overlay. In addition, it was known that silicon particles are hard and directly abrade the mating material (steel crankshaft, etc.), directly affecting conformability or compatibility. This was done by applying the theory that fine hard particles are uniformly dispersed in the material, and this theory itself is inherent in, for example, the applicant's earlier patent application, and is well known in the field of sliding materials. This is one well-known theory. The present invention is based on a theory completely different from the conventional technology as described above, and is a tin-containing aluminum alloy that has significantly higher conformability and seizure load than the conventional technology and can be used as a bearing without an overlay. The company provided bearings. The aluminum alloy bearing according to the present invention has a weight percentage of 1 to 35% tin and 0.5 to 11% tin.
an alloy containing at least one element from the group consisting of manganese, iron, molybdenum, nickel, zirconium, cobalt, titanium, antimony, chromium and niobium, the remainder being substantially aluminum, is adhered to the backing metal, The bulk particles consisting of or containing the at least one element having a dimension of 5 microns or more and 40 microns or less as measured by the major axis of the particles are 3.56 x 10 ^-2 mm in any part of the alloy. It is an aluminum alloy bearing that has 5 or more per ² and can be used without an overlay. Hereinafter, the constituent elements of the present invention will be explained in the order of chemical composition, hard particles, and bearing structure. First, regarding the chemical composition, tin is an element that changes the properties of the aluminum alloy into softness, giving it lubricating performance and conformability suitable for bearings. Familiarity here is defined by a technical concept that is generally accepted in the art as described above, and is hereinafter referred to as familiarity of the general concept. When the tin content exceeds 35%, the general conformability and lubricity improve, but the hardness of the aluminum alloy decreases and the strength as a bearing becomes insufficient. On the other hand, if the tin content is less than 1%, the compatibility of the general concept of aluminum alloy as a bearing alloy deteriorates. How to determine the amount of tin added in the range of 1 to 35% should be determined appropriately depending on the application, but generally speaking, it depends on the load applied to the bearing, that is, the amount of tin added via the piston of the internal combustion engine. When the explosive load to be applied is large, the tin content is preferably low, for example 5 to 10%, and when the explosive load is small, the tin content is preferably high. On the other hand, if there is a concern about bearing seizure due to high loads and high speed rotation, the tin content may be increased, for example 15 to 20%. In order to ensure that the fatigue strength and high-temperature hardness of tin-containing aluminum alloys are sufficient for the performance required for bearings, it is important that tin particles are finely dispersed in the alloy. The present applicant thought about it and proposed in a previous patent application to prevent the coarsening of tin particles, which tends to occur when the content exceeds 15%, by using fine particles of chromium or the like. However, in the present invention, since the special running-in effect described later is substantially responsible for bearing performance, there is no problem in using the bearing as a bearing for an internal combustion engine, even if miniaturization of tin particles is not so important. The preferred tin content is 3
~20%. Manganese, iron, molybdenum, nickel, zirconium, cobalt, titanium, antimony, chromium, and niobium (hereinafter collectively referred to as manganese, etc.) are elements that bring about the special conforming effect described below, and their content is less than 0.5%. If it exceeds 11%, the breaking-in effect of the bearing alloy will not be improved, and the fatigue strength and seizure load will tend to decrease. The preferred content of manganese and the like is particularly 1 to 9%. When two or more types of manganese or the like are added, the lower limit of each element is preferably 0.1%. Next, particles generated by adding manganese or the like will be explained. Manganese and the like crystallize either in the form of a single metal or in the form of an intermetallic compound of manganese and aluminum, and it is not possible to analyze the components of the crystallized product. However, by adding manganese or the like to a tin-containing aluminum alloy, hard particles other than soft particles crystallize. Therefore, particles consisting of or containing manganese etc. are crystallized, and these are hereinafter referred to as hard particles. According to the findings of the present inventors, a special running-in effect that does not appear when the major axis dimension (hereinafter simply referred to as the dimension) of the hard particles is less than 5 microns appears when it is 5 microns or more, and the bearing performance of tin-containing aluminum alloys is dramatically improved. This effect is observed when 5 or more hard particles of 5 microns or more are present per 3.56 x 10 ^-2 mm ² , and becomes more pronounced as the number increases. On the other hand, when the size of the hard particles exceeds 40 microns, the fatigue strength of the tin-containing aluminum alloy decreases. From this point of view, the upper limit of the content of manganese, etc. in the alloy of the present invention is 11% as mentioned above. In addition, the significance of specifying coarse hard particles, that is, hard particles with a size of 5 microns or more as a component in the present invention, is that, in a negative sense, fine hard particles do not contribute to improving bearing performance. In this respect, the bearing performance of conventional aluminum-based alloy bearings is different from that of conventional bearings. In other words, in the applicant's previous application, fine silicon particles indirectly improve bearing performance through the control of the shape of tin particles, as mentioned above, and in the above-mentioned SAE journal paper, both theoretically and experimental data However, finer silicon particles provide better bearing performance. However, in the present invention, coarse hard particles have much better performance other than fatigue strength. Therefore, if we were to actively discuss the significance of coarse hard particles, we would say that they are caused by minute irregularities caused by the machining accuracy of the shaft, which is the mating material of the bearing containing such hard particles, or by the fact that the shaft has a roughness around the recesses caused by falling graphite. , as the hard particles become flattened,
It is thought that these favorable sliding movements occur when an oil film is always present between the bearing and the shaft. In addition,
Conventionally, in the field of bearings, it is common to think that soft components such as tin contribute to the conformability of aluminum alloys, and the idea that hard particles directly contribute to flattening the unevenness of the mating material was developed by the inventor. As far as I know, there is nothing other than the above-mentioned SAE magazine, so I will refer to the conforming effect caused by hard particles as the special conforming effect. However, SAE magazine emphasizes that the effect of such hard particles (silicon particles) improves compliance, but has the opposite effect on compliance, and as a result the bearing must have an overlay. .
Here, compatibility is the bearing's ability to adapt to machining misalignment between the shaft and the bearing.
It is semantically equivalent to familiarity (familiarity based on general concepts). Therefore, neither in the SAE journal nor in any other published papers to the best of the inventor's knowledge, there is no idea that hard particles scrape away the surface irregularities of the mating shaft, flatten it, and contribute to conformability. There has also been no published experimental data showing that bearing performance such as seizure load is improved when a large amount of is present in a bearing. Therefore, the above-mentioned special running-in effect is a feature of the present invention, and bearing performance, such as seizure load, is significantly improved when compared with materials that only have a conventional running-in effect in the general concept. Of course, the alloy of the present invention contains tin, but it is believed that the embedding of the soft metal into the surface of the mating material due to the general concept of conforming action is achieved after the unevenness of the mating material is flattened by a special conforming action. As a result, it is believed that the combination of both will provide excellent performance as a bearing for automobile internal combustion engines. The above-mentioned special running-in effect is particularly effective when the mating shaft is made of spheroidal graphite cast iron or flaky graphite cast iron. Spheroidal graphite cast iron tends to be used in place of conventional forged shafts in order to reduce the cost of shafts such as internal combustion engine crankshafts, but graphite particles are scraped off from the shaft surface during shaft polishing.
The traces of the fallen spheroidal graphite particles are many depressions or cavities, and the iron-based matrix around them is work-hardened sharp burrs or edges. Conventional tin-containing aluminum bearing alloys have had the problem that these burrs cause abnormal wear on the bearing surface. According to the inventor's research, the soft aluminum matrix is scraped off by the burr and incorporated into the recess, and the aluminum and the bearing material are very likely to stick together due to the lack of aluminum conformability, resulting in seizure immediately. It was also revealed. However, in the tin-containing aluminum alloy according to the present invention, the coarse hard particles scrape off the burrs and make the area around the recesses smooth. As a result, seizure does not occur even under high loads, and seizure resistance is significantly improved. The thickness of the bearing alloy mentioned above is 0.1~1mm, especially 0.2~
0.5mm is preferred. Apply anti-rust oil to the bearing alloy if necessary. The bearing of the present invention has a structure that does not require an overlay because it has excellent seizure resistance for the reasons described above. The bearing alloy is bonded with or without an underlying layer by a method such as pressure welding. The tin-containing aluminum alloy of the present invention has (A) 0.1
to 10%, preferably 1 to 6%, of at least one of lead, cadmium, indium, thallium, and bismuth (hereinafter referred to as lead, etc.), and (B) 0.1 to 2%, preferably 0.2 to 1% of copper, and It further contains at least one type of magnesium (hereinafter referred to as copper etc.). Lead etc. have the effect of improving the lubricity and general conformability and wear resistance of tin-containing aluminum alloys. Generally, when lead, etc. are added to Al-Sn binary alloys, they are alloyed with tin particles, and the tin particles, whose melting point has been lowered, are more likely to move and melt, making it difficult for bearings to operate under high loads continuously. In some cases, the Al-Sn-Pb alloy partially melted and separated from the bearing. However, in the present invention, since the special conformability makes a large contribution to the improvement of bearing performance, lowering the melting point of alloy particles such as tin-lead does not pose a serious drawback. Lead content
If it is less than 0.1%, the effect is insufficient, and if it exceeds 10%, the fatigue strength required for the bearing will be insufficient. Copper and the like increase the high-temperature hardness of tin-containing aluminum alloys and contribute to improving the fatigue strength of bearings. If the content of copper, etc. is less than 0.1%, the effect of improving high-temperature hardness will be small, and if it exceeds 2.0%, the tin-containing aluminum alloy will become too hard, impairing its rollability, and will also reduce its seizure resistance and corrosion resistance to lubricating oil. The high-temperature hardness improvement effect of copper, etc. becomes even more pronounced when it coexists with chromium, and the hardness does not decrease much even at temperatures above 200°C. Next, a method for controlling the size and number of hard particles will be explained. Judging from the phase diagram of binary alloys such as Al-Mn, the hard particles are considered to be as follows depending on the type of alloying element. Mn:MnAl ₄ and MnAl ₆ Fe:FeAl ₃ Mo:MoAl ₃ Ni:NiAl ₃ Zr:ZrAl ₃ Co:Co ₂ Al ₉ Ti:TiAl ₃ Sb:AlSb Nb:NbAl _3The above intermetallic compounds are considered to be present during casting. Crystallization forms are diverse. These crystallized substances are separated and reduced in size during the process of rolling the cast alloy to the required thickness for the bearing. Such casting-
Most of the hard particles obtained by the rolling method are 5 microns or less, and although some are rarely 10 microns or less, their number per unit area is small and they are acicular or flat. Further, intermediate annealing is performed after rolling, and the temperature is selected to be approximately the recrystallization temperature, so that the hard particles hardly become coarse due to the intermediate annealing. After obtaining a bearing alloy of a predetermined thickness by casting and rolling (intermediate annealing) as described above, this is pressure-welded to a backing steel plate, and at this time Al-Fe
The conventional manufacturing method for tin-containing aluminum alloy bearings has been to annealing the tin-containing aluminum alloy bearings after pressure welding at a temperature below the intermetallic compound formation temperature, for example, 350°C. Even at this temperature of 350°C, the hard particles hardly became coarse, and as a result, fine hard particles, mostly less than 5 microns, were present in the final bearing product. On the other hand, in order to have at least 5 coarse hard particles of 5 microns to ⁴⁰ microns ^per 3.56
It has been found that the most effective method is to perform high-temperature heat treatment at ℃ while adjusting the holding time. That is,
Controlling the size of hard particles in processes other than the heat treatment process before pressure welding is less effective; for example, controlling the heating temperature, rolling reduction rate, etc. in the rolling process, controlling the cooling rate in the casting process, or intermediate annealing can reduce the size of the hard particles. Dimensional control is extremely difficult, and heat treatment during or after pressure welding may result in the formation of Al-Fe intermetallic compounds or the dissolution of low melting point components such as tin in the aluminum alloy of the bearing just before completion. , these have undesirable consequences on bearing performance, especially on the familiarity of the general concept. Table 1 shows how the number of crystallized hard particles changes depending on the content of manganese etc. in the high temperature heat treatment before pressure bonding as described above. Table 1 shows the approximate numbers calculated on the assumption that all manganese etc. are crystallized as cubic hard particles having the dimensions shown in the horizontal column. In reality, most of the hard particles smaller than 5 microns are coarsened into hard particles larger than 5 microns by high-temperature heat treatment before pressure bonding. Therefore, Table 1 is useful as a material for controlling hard particles in the aluminum alloy of the present invention.

[Table] When the content of manganese etc. is 0.5%, the number of hard particles is 340 from Table 1. Even if a part of manganese etc. crystallizes as hard particles of less than 5 microns, it is easy to secure 5 or more particles. The number of 5 micron hard particles is 340 to 3500 depending on the content of manganese etc. The number of hard particles of 5 to 10 microns in actual bearing alloys is smaller than this, but due to high temperature heat treatment before pressure welding,
The ratio of coarse particles of microns or more to fine particles of less than 5 microns is increased. For example, high-temperature heat treatment at 350 to 450° C. before pressure bonding can be used to increase the proportion of coarse manganese particles having a size of 5 to 10 microns. According to Table 1, when the content of manganese etc. is 3%, the number of hard particles is 4 if manganese etc. are completely precipitated as particles of 40 microns. If this number is one, it is possible to crystallize both 5 to 30 micron hard particles and 40 micron hard particles. Therefore, it is possible to crystallize a specific number of coarser hard particles within the range of the content of manganese, etc. in the tin-containing aluminum alloy of the present invention, and within the particle size range of 5 to 40 microns. A preferred example of this is as follows. (a) 5 or more hard particles over 10 microns, (b) 2 or more hard particles over 20 microns, (c) 1 or more hard particles over 30 microns. Next, the morphology of the hard particles according to the present invention will be explained. Generally, the hard particles in rolled tin-containing aluminum alloys are needle-shaped, and their longitudinal direction often coincides with the rolling direction, but when the high temperature heat treatment of the present invention is performed, the hard particles have a relatively narrow width in the direction perpendicular to the rolling direction. It grows larger and becomes flat or lumpy. These hard particles are formed on the horizontal surface of the bearing, that is, the surface in contact with the shaft of the mating material,
Appears flat or lumpy when viewed from the ground. Preferably, it is blocky when viewed in the horizontal and vertical planes. And 5
Most of the hard particles larger than microns are in the form of lumps,
There are few flat shapes, and there are almost no needle shapes in a given area. Such a blocky shape is extremely effective in terms of special conforming effect. Furthermore, as a method for observing the structure of the tin-containing aluminum alloy, the dimensions of the hard particles are measured on the above-mentioned horizontal plane, excluding the mechanically altered outermost surface. In addition to hard particles, tin particles and other particles (phases) are present in this alloy, but in order to identify the hard particles from these, tin and other particles are white when viewed with a metallurgical microscope, and hard particles are gray. (dark gray). The present invention will be explained below using examples. In these Examples, unless otherwise specified, the manufacturing method of the bearing or bearing alloy was as follows. An aluminum alloy of a predetermined composition was continuously cast to form a plate with a thickness of 15 mm, and after peeling, the cast plate was continuously cold-rolled to a plate thickness of 6 mm. Next, intermediate annealing (350°C) was performed, followed by cold rolling to obtain an aluminum alloy thin plate. Subsequently, high temperature heat treatment is performed in the range of 350 to 550°C to obtain hard particles of the desired size, and then the aluminum alloy thin plate is preheated to 230°C, pressure welded to a similarly preheated back metal plate, and then heated to 350°C.
The bearing was completed by annealing for pressure welding. When testing the performance of the bearing alloy itself, the steps after pressure welding were omitted. Example 1 Table 2 shows the composition and hard particle distribution of the aluminum alloy test material. Unless otherwise specified in the table and below, the number of hard particles refers to the number per 3.56×10 ⁻² mm ² .

【table】

[Table] The test materials in Table 2 were subjected to seizure load measurements under the following conditions. Condition A Tester: Journal type seizure tester Conditions: Compatible shaft - FCD70 Shaft Lubricating oil type - SAE10W - 30 Shaft surface roughness - 0.4 to 0.6 μmRz Lubricating oil temperature - 140 ^{± 2.5} ℃ Shaft rotation speed - 1000 rpm Shaft diameter -52mm Shaft hardness - Hv200-300 Load - 50Kg/cm ² Increased by the same amount at 30mm intervals Bearing roughness - 1 to 1.8μmRz Bearing diameter - 52mm The seizure load measurement results are shown in Figure 1. In FIG. 1, the horizontal axis represents the number of maximum dimension hard particles of the sample material. The test materials were divided into five groups from A to E according to the maximum particle size in the five ranges shown in Table 1.
It is shown in FIG. The following facts become clear from this figure. (a) The seizure load is influenced by the number of hard particles with the largest size, and is almost unaffected by the number of hard materials with smaller sizes. (b) The seizure load increases with the number of hard particles of maximum size. However, there is almost no increase in the seizure load for the test materials of Group A, and there is a significant increase in the seizure load for the other groups containing hard particles with larger dimensions. Based on the above facts (a) and (b), the present invention is limited to five or more particles of manganese, etc., each having a minimum size of 5 microns. Example 2 Seizure load and fatigue strength were measured for the test materials shown in Table 3 (1). The conditions for measuring fatigue strength were as follows. Condition B Tester: Alternating load tester Conditions: Mating material shaft - S55C Lubricating oil type - SAE10W - 30 Shaft surface roughness - 0.8μmRz Lubricating oil temperature - 140±2.5℃ Lubricating oil pressure - 5Kg/cm ^2- axis rotation speed - 3000rpm Shaft Diameter - 52〓 Shaft hardness - Hv500~600 Number of shaft rotations - 10 ⁷ times Bearing roughness - 1~1.8μmRz Bearing diameter - 52 x 20mm The measurement results are shown in Table 3 (2). From this, it can be seen that according to the present invention, the seizure load is improved and the fatigue strength is not deteriorated by coarse hard particles. In addition,
In Table 3 (1), the number of hard particles less than 5 microns was not measured. Furthermore, this mating material shaft is made of carbon steel (S55C) for mechanical structures, and it can be seen that the tin-containing aluminum alloy according to the present invention is also effective in the case of iron-based mating materials in which carbon does not exist in the form of graphite.

【table】

【table】

[Table] Example 3 When the same experiment as in Example 2 was conducted on a sample material with a manganese content of 1%, Table 4 (1) and
Similar results were obtained as shown in (2).

【table】

【table】

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[Table] Example 4 Example 2 for the sample material with a manganese content of 3%
The results of experiments conducted in the same manner as above are shown in Tables 5 (1) and (2). This result is almost the same as in Example 2.

【table】

【table】

【table】

[Table] Example 5 Example 2 for sample material with manganese content of 11%
The results of experiments conducted in the same manner as above are shown in Table 6 (1) and (2). The experimental results are almost the same as in Example 2.

【table】

[Table] Example 6 Example 1 For sample material C2, the surface roughness of the spheroidal graphite cast iron shaft of the mating material was varied, and the seizure load was measured under condition A. The results are shown in FIG. As a comparative example (COMP), the seizure load of a 20% Sn-1% Cu-Al alloy was measured. From the figure, it is clear that the seizure load of the material of the present invention is good regardless of the surface roughness of the mating material. In addition, the comparative material does not have precipitation of hard particles and imparts seizure resistance to the aluminum alloy due to the compatibility of the general concept of a soft tin phase. Therefore, from FIG. 2, it is possible to see the difference in the effects of the general concept and special conformability on seizure resistance. Furthermore, since the mating material is spheroidal graphite cast iron, it is well understood that the material of the present invention has high seizure resistance against spheroidal graphite cast iron. Example 7 Figure 3 shows the results of measuring the seizure load (condition A) when the hard particle distribution was kept constant and the contents of all elements such as manganese were varied, as in the test materials shown in Table 7. The results of measuring the fatigue strength (condition B) are shown in FIG. FIGS. 3 and 4 show the values obtained by testing three of each sample material.

[Table] From Figure 3, it can be seen that the seizure load becomes maximum when the content of manganese etc. is about 4%. As mentioned above, the seizure load is controlled by the number and size of the maximum hard particles in the content range of the present invention, but in this example, where the number of particles with a lower limit of 5 microns is controlled constant, the content of manganese, etc. Some influence can be seen. This is thought to be due to fine hard particles of less than 5 microns. From FIG. 4, it can be seen that when the content of manganese etc. exceeds 5%, the fatigue strength decreases. This is also considered to be due to the fine particles mentioned above. Example 7 Experiments similar to Examples 2, 3, 4, and 5 were conducted by changing other types of lead, copper, etc. The results are shown in Table 8 (1) and (2) (numbers 40 and 41 are missing). From these tables, it can be seen that sufficient seizure load and fatigue strength can be obtained with various arbitrary components.

【table】

【table】

【table】

[Table] Example 8 The following experiment was conducted using the test materials shown in Table 2. (1) Effect of lubricating oil temperature At 80°C and
The seizure load was measured at an oil temperature of 140°C. Similar measurements were conducted using a 20% Sn-1% Cu-Al alloy as a comparative material (COMP). The results are shown in FIG. It can be seen that there is an extreme difference in the seizure load at high temperatures between the comparative material and the material of the present invention. (2) Influence of mating materials (forged shaft and spheroidal graphite cast iron) at oil temperature of 140°C C2 specimen and 20%Sn-1%Cu-Al alloy were used as comparative specimens under condition A (however, oil temperature was 140°C). Fig. 6 shows the results of measuring the seizure load at 30°C. There is no big difference in seizure load between the test materials of the present invention and comparative examples when the mating material is a forged material, but an extreme difference appears when the material is made of spheroidal graphite cast iron (DCI). (3) Wear resistance The amount of wear was measured for the C2 sample material under the following conditions. Condition G Tester: Mixed lubrication tester Conditions: Mating material shaft - FCD70 Shaft surface roughness - 0.8 to 0.9 μm Rz Lubricating oil type - Liquid paraffin Shaft rotation speed - 100 rpm Shaft diameter - 40φ (mm) Shaft hardness - Hv200 to 300 Load - 25Kg Test time - 5Hrs For comparison, 20% without manganese etc.
The wear amount of the Sn-1% Cu-Al alloy (COMP) was measured under Condition G. The wear amount measurement results are shown in Fig. 7. While the comparative material shows progressive wear over time, the material of the present invention shows almost no increase in the amount of wear after about one hour. The inventor thinks about such a difference as follows. In the comparative material, the soft tin phase is mainly scraped off by the shaft of the mating material, so that the comparative material is constantly worn. In the material of the present invention, the coarse hard particles present on the bearing surface wear out the protrusions of the surface roughness of the mating shaft and the edges such as burrs around the spherical graphite present on the surface at the initial stage of sliding. By scraping the surface of the shaft and changing it into a shaft surface that provides a better sliding condition for the bearing, it creates a state close to fluid lubrication and prevents direct contact between the shaft and the bearing, which stops the progress of bearing wear. It is assumed that Example 9 An aluminum alloy containing 15% Sn, 3% Pb, and 0.5% Cu, with the content of manganese etc. changed in the same manner as Samples 33 to 39 in Table 7, was cold rolled. A bearing was manufactured using the same manufacturing method as the test material of the present invention, except that annealing of the rolled plate was omitted. The results of measuring the seizure load of this bearing under condition A are shown in FIG. Comparing Fig. 8 showing the seizure load of the test material without coarsening of particles with Fig. 3, it is found that the test material (Fig. ) has significantly superior heat resistance and the variation in seizure load is not small. The amount of wear of the above-mentioned inventive and comparative materials was measured under the following conditions. Condition C Tester: Mixed lubrication test machine Conditions: Compatible shaft - FCD70 Shaft surface roughness - 0.8 to 0.9μmRz Lubricating oil type - Liquid paraffin Shaft rotation speed - 100 rpm Shaft diameter - 40φ (mm) Shaft hardness - Hv200 to 300 Load - Figure 9 shows the measurement results of 25Kg wear amount. It can be seen from this drawing that the wear resistance of tin-containing aluminum alloys is significantly improved when the hard particle size is controlled by performing the high temperature heat treatment according to the present invention. Example 10 Hard particles in the horizontal plane when the annealing temperature before pressure welding of an aluminum alloy containing 3% Sb, 15% Sn, 3% Pb, and 0.5% Cu was changed as follows.
A sketch of the microscopic structure of Sb is shown in each figure. 270°C (low-temperature heat treatment in comparative example) Fig. 10 Slow cooling after heating at 500°C Fig. 11 The hard particles change from flat to lumpy due to the high-temperature heat treatment of the present invention.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between seizure load and the number of maximum dimension hard particles, Figure 2 is a graph showing the relationship between seizure load and shaft surface roughness, and Figure 3 is a graph showing the relationship between seizure load and the content of manganese, etc. Figure 4 is a graph showing the relationship between fatigue strength and content of manganese, etc. Figure 5 is a graph showing the relationship between seizure load and lubricating oil temperature, Figure 6 is seizure depending on the type of mating material shaft Figure 7 is a graph showing the change in load, Figure 7 is a graph showing the change in wear amount over time, Figure 8 is a graph showing the relationship between seizure load and the content of manganese, etc., Figure 9 is the relationship between the amount of wear and the content of manganese, etc. Graphs showing, Figures 10 and 11
The figure is a sketch of the microscopic structure of the aluminum alloy sample. In the drawing, COMP refers to the comparative material, and other numbers and symbols refer to the numbers of the sample materials.

Claims (1)

[Claims] 1. 1 to 35% tin, 0.5 to 11% manganese, iron, molybdenum, nickel, by weight percentage
Zirconium, cobalt, titanium, antimony,
At least one member of the first group consisting of chromium and niobium
element, 0.1 to 10% of at least one element of the second group consisting of lead, cadmium, indium, thallium and bismuth, and at least one element of the third group consisting of 0.1 to 2% of copper and magnesium. particles containing an alloy with the remainder substantially consisting of aluminum adhered to a backing metal, and having a dimension of 5 microns or more and 40 microns or less as measured by the major axis of the lump particles consisting of or containing the elements of the first group. An aluminum-based alloy bearing in which there are 5 or more per 3.56×10 ^-2 mm ² in any part of the alloy, and which can be used without an overlay. 2. The aluminum-based alloy bearing according to claim 1, wherein the particles having a size of 10 microns or more and 40 microns or less are present in any part of the alloy in an amount of 5 or more per 3.56×10 ^-2 mm ² . 3. The aluminum alloy bearing according to claim 1 or 2, wherein the content of tin is 3 to 20%, and the content of at least one element of the first group is 1 to 9%. 4. The aluminum alloy bearing according to any one of claims 1 to 3, wherein the shaft of the bearing mating material is made of spheroidal graphite cast iron or flake graphite cast iron. 5. The aluminum-based alloy bearing according to claim 4, wherein the particles having a particle size of 55 to 40 microns are in the form of a lump when viewed in a horizontal plane, that is, a plane parallel to the plane in contact with the axis of the mating material.