JPS5818985B2 - Al-Sn bearing alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an AI-Sn bearing alloy that exhibits less growth of Sn particles and less decrease in hardness in high-temperature conditions (excellent fatigue resistance and wear resistance). It provides a bearing base metal that is suitable for use after several times of rolling and annealing, and is particularly suitable for use with spheroidal graphite cast iron shafts, which require harsh conditions for bearings. AlSn
The present invention provides a series bearing alloy.

In recent years, internal combustion engines for automobiles have been required to be smaller in size and have higher output, and as well as the installation of blow-by gas reduction devices for exhaust gas purification measures, bearing sliding materials have become more expensive. The bearings are used under conditions of high loads and high temperatures, and under such adverse conditions, conventional bearing sliding materials suffer from fatigue failure and abnormal wear, causing trouble.

Furthermore, in order to reduce costs, there is a tendency to shift from conventional forged shafts to spheroidal graphite cast iron shafts, which are cheaper to process, or to shafts with larger shaft roughness. , even better fatigue resistance under high humidity conditions,
Improvement in seizure resistance and further improvement in wear resistance are required.

Conventional aluminum bearing alloys are mainly AlS.
n-based alloy, e.g. AI (balance) 5n (by weight percentage)
3,5~4.5) 5i(3,5~4.5) Ou
'('0.7~1.3) t A I (remainder)
Sn(4~8)Si(1~2)-Cu
(0,1~2)tNl(0,1~1),A
I (remainder) -8n (3~40) Pb (0,1~
5) Cu(0,2-2)-sb(o,1-3)-
8i (0,2~3) Ti (0,01~1), AI
(Remainder) 5n (15~30) 0u (0,5~
2) tAl (remainder) Sn(1-23) Pb
(1,5~9) -0u (0,3~3)Si(1~
Al-8R alloys such as 8) are used.

However, when conventional alloys such as these are used in the bearings of automobile internal combustion engines under the severe conditions mentioned above, fatigue failure may occur in a short period of time, such as when the internal combustion engine continues to operate under high load. was there.

This is because the oil in the internal combustion engine becomes particularly hot during continuous high-load operation, and for example, the temperature of the oil in the oil pan is 130°C.
℃ to 150℃, it is expected that the temperature of the sliding surface of the bearing will be quite high.As a result, in conventional AlSn alloys, the hardness rapidly decreases at high temperatures and S
Melting and migration of n occurs, and this is considered to be the cause of the decrease in fatigue strength.

The inventors of the present invention processed an alloy whose hardness does not decrease under high temperatures and an alloy in which Sn does not easily move into the shape of an internal combustion engine bearing.
The above consideration is supported by the fact that an improvement in fatigue strength was observed as a result of a dynamic load fatigue test conducted under high oil temperature.

In addition to the decrease in fatigue strength due to the decrease in high-temperature hardness described above, in conventional AlSn-based alloys, Sn in the alloy structure
Coarsening of particles also causes a decrease in fatigue strength.

In other words, aluminum bearing alloys are generally formed by pressure-welding an AlSn-based alloy to a backing steel plate, but in order to increase the adhesive strength of both metals, annealing is essential after pressure-welding. Specifically, this annealing is performed on Al-Fe
Below the temperature at which intermetallic compounds precipitate, the higher the temperature (longer the time), the greater the wedge bonding strength.

However, conventional AlSn-based alloys have a drawback in that when subjected to high temperatures during annealing, coarsening of Al grain boundaries and Sn particles progresses in the alloy structure.

In other words, when conventional aluminum bearing alloys are annealed to increase the adhesive strength with the backing steel plate, the Sn particles become coarser, and this coarsening causes a decrease in the fatigue strength of the Al-8Sn alloy.

Furthermore, when these conventional AlSn-based alloys are used in combination with a spheroidal graphite cast iron shaft, there is a drawback that they cause extreme wear and are prone to fatigue failure.

The inventors of the present invention added various additive elements to the AlSn-based alloy to improve its high-temperature hardness and fatigue strength, and as a result, they have already added Sn, Or, Cu, etc. manufactured elsewhere, to A1. Developed the alloy and applied for a patent (Japanese Patent Application 1982-269
No. 0).

Furthermore, in addition to Sn, Or, and O, Pb and/or In were added to develop an alloy with particularly improved conformability while maintaining fatigue resistance.
18225).

As a result of further research, the present invention added W, CetNbtVtBa,
We have discovered a bearing material that can further increase hardness and significantly improve wear resistance while maintaining the same fatigue resistance and conformability by adding one or more types of Oa and precipitating them in a dispersed manner. It was made by

These dispersed precipitates are extremely hard, reaching hundreds of Guitzkaas hardnesses, and are considerably harder than the bearing's mating material, that is, the shaft.These hard precipitates significantly improve the wear resistance of the bearing.

The AlSn alloy of the present invention has a weight percentage of 3.5 to 35%.
of Sn, 0.1 to 10% of Or, and W.

Based on an AlSn-based alloy containing one or more of Ce, Nb, V, Ba, Ca, etc. in a total amount of 1 to 10% or less, and the balance essentially consisting of AI, and the amount of SnO is determined by the additive element. It is characterized by being the largest in the
lSn alloy with Or, W, Ce, Nb, V, B
By adding one or more types of a, Oa, etc., Sn is made finer and the hardness is improved.In particular, there is almost no movement and growth of Sn in high temperature conditions, and there is little decrease in high temperature hardness. This was recognized.

This was confirmed by the improvement in fatigue strength under high oil temperature when a dynamic load fatigue test was conducted.

In addition, it was confirmed that wear resistance was also improved.

Such AlSn-based alloys are suitable for use as a bearing base metal material for the mating material that has a large effect on the sliding characteristics of the bearing, that is, for the shaft, which is made of spheroidal graphite cast iron, or for shafts with large shaft roughness. Bearing alloy material.

The reason for limiting the Sn content to 3.5 to 35% by weight is that Sn is an element added primarily for the purpose of lubrication, but adding 35% or more of Sn improves compatibility and lubricity. However, if the hardness is less than 3.5%, the bearing base metal becomes too hard (too hard) and has poor conformability.

The upper limit for the amount of Sn added in conventional AlSn alloys is about 15% in order to isolate and disperse Sn, and the reason for this is that if more than 15% is added, the Sn particles in the alloy will be dispersed in the AI. It was believed that this was because the hardness decreased as the hardness decreased because the hardness could no longer be isolated and dispersed and began to exist in a continuous state, but in the present invention, due to the effect of adding other elements described later
Even when this was added up to 35%, there was no practical problem.

In addition, how to determine the amount of Sn added within the range of 3.5 to 35% should be determined appropriately depending on the application, but in general, it depends on the amount of load applied to the bearing. When the load is small, it is better to increase the Sn amount.

From another point of view, it is better to increase the amount of Sn when used in a state where there is a concern about seizure, and to decrease the amount of Sn when there is no concern.

However, recently, bearings have become hot due to high oil temperatures, and this has caused problems such as deformation, seizure, and fatigue of the bearings, so it is also necessary to determine the amount of Sn from the viewpoint of minimizing deformation at high temperatures.

Or is particularly effective in preventing increase in hardness and softening at high temperatures, and in not causing coarsening of Sn particles even during annealing.

First, let's talk about increasing hardness and preventing softening at high temperatures.
If the amount of Or added is less than 0.1% by weight, no improvement in high-temperature hardness can be expected; if it is added more than 1.0%,
As will be described later, the Al-0r gold metal compound cannot be finely and uniformly dispersed and the effect of addition is weakened, so the amount added is limited to 0.1 to 1□0.

To explain this improvement in high-temperature hardness in more detail, Or increases the recrystallization temperature of AI by forming a solid solution in AI, and increases the hardness of the AI base by forming a solid solution. Even by rolling several times, the hardness increases compared to when it is cast.

Increasing the recrystallization temperature is effective in maintaining stable mechanical properties even in the high-temperature range that internal combustion engine bearings are exposed to. Improves bearing strength in high temperature areas.

In addition, the intermetallic compound of Al0r that precipitates beyond the solid solubility limit has a Witzkars hardness of about 370, which means that this compound is fine (dispersion helps maintain high temperature hardness, so it is necessary to disperse an appropriate amount). produces good effects.

As mentioned above, the appropriate amount range here means 1.0% or less, and within this range, the precipitates are uniform and fine, resulting in an increase in hardness.

Next, the effect of inhibiting the coarsening of Sn particles by adding Or will be described.

The coarsening of Sn particles is a phenomenon that occurs when Al-Sn alloys are exposed to high temperatures due to the movement of A1 grain boundaries and Sn particles. Since compound precipitates are formed and these precipitates are finely dispersed in the AI metal, this intermetallic compound directly prevents the movement of A1 grain boundaries and at the same time prevents the growth of AI crystal grains. This is thought to be because it prevents the movement of Sn particles, that is, the coarsening of Sn particles.

This leads to keeping the Sn particles, which have been refined through repeated rolling and annealing, as they are, resulting in the various effects described above.

Although this phenomenon is observed even when the amount of Sn is small, it has a large effect when the amount of Sn is relatively large (approximately 10% or more), especially when Sn starts to exist continuously at approximately 15% or more. A remarkable effect can be seen.

Furthermore, the fact that the Sn particles remain fine and exist in the AI metal is also effective in preventing the elution phenomenon of Sn particles, which have a low melting point of 232°C, at high temperatures. From this point of view, the effect of preventing a decrease in hardness is confirmed.

The above description describes the effect of inhibiting the coarsening of Sn particles in relation to annealing, but this also applies when the environment in which this bearing material is used is at a high temperature comparable to that of annealing.
Therefore, fatigue strength can be improved by preventing a decrease in high-temperature hardness.

Next, the addition of one or more of W, Oe, Nb tVtBa yOa, etc. will be described.

The reason for limiting the total content of these substances to 1 to 10% is that below 1%, the amount of precipitates is small and the wear resistance effect is not exhibited, and when it exceeds 10%, there are too many precipitates (too much).
The rolling property deteriorates, making it difficult to repeat rolling and annealing, and the refinement of Sn particles is hindered.

The forms of precipitates include precipitates consisting of units of these additive elements, precipitates consisting of intermetallic compounds of these additive elements, precipitates consisting of intermetallic compounds of these additive elements and AI, and precipitates consisting of intermetallic compounds of these additive elements with each other. There are precipitates made of intermetallic compounds and intermetallic compounds of AI, but no matter what form the precipitates are formed in, they are effective in improving wear resistance.

These precipitates are extremely hard with a Witzkars hardness reaching several hundred, so these precipitates can significantly reduce the wear of the bearing due to friction with the shaft. Diversification produces good results.

As mentioned above, the appropriate amount range means 1 to 10%, and within this range, the above-mentioned precipitates are uniformly dispersed and do not adversely affect conformability etc. (it has the effect of improving wear resistance).

In this case, even if each element is added in an amount of less than 1%, if the total amount is 1% or more, the effect of the present invention is sufficiently achieved.

Further, it is preferable to add Or and these elements at the same time since this further improves the high-temperature hardness.

The above-mentioned AlSn-based alloy is generally used in the form of a bearing by being pressed onto a backing steel plate, and is particularly effective when used on a spheroidal graphite cast iron shaft.

In other words, the mating material for a bearing greatly affects the bearing properties. For example, when a conventional AI-S n-based bearing is used in combination with a spheroidal graphite cast iron shaft, the bearing performance such as seizure resistance and wear resistance can be significantly impaired. do.

Recently, spheroidal graphite cast iron shafts, which are cheaper to process, have been increasingly used in place of steel shafts.

However, in spheroidal graphite cast iron, soft graphite is scattered in the iron base, and for this reason, when the shaft is ground, abrasive particles with sharp edges are generated around the graphite.

If a bearing is slid against a shaft with such abrasive cracks under such a high load that the oil film thickness is the same as the shaft and bearing surface roughness, the bearing surface, which is softer than the shaft, will be cut. As this situation progresses, the bearing surface becomes rougher and the clearance between the shaft and bearing increases.
As a result, the oil film may no longer be formed, or the oil film may not be formed due to oil film rupture, resulting in more direct contact, that is, metal contact, between the shaft and the bearing, leading to seizure.

However, the alloy according to the present invention contains precipitates that are harder than the spheroidal graphite cast iron shaft, ie, W, Oe, and Nb.

The effect of dispersing the precipitates produced by adding one or more of V, Ba, Oa, etc. in the At ground, and removing the polished burrs of the spheroidal graphite cast iron shaft by these precipitates, and these precipitates. It also has the effect of preventing the transfer and adhesion of oil, thereby suppressing the progress of wear on the bearing surface in a relatively short period of time, and creating a stable oil film. As a result, it is recognized that the wear resistance is particularly improved for spheroidal graphite cast iron shafts.

A similar effect is also observed for shafts with very rough shafts.

A second invention of the present invention is an AlSn-based alloy having the above-mentioned composition, further adding O and/or Mg in a weight percentage of 3% or less, excluding O. or) Mg is added to further reduce the decrease in hardness at high temperatures.

In order to prevent the decrease in hardness at the same time, this should be set to 0.5~
It is preferable to set it to 3.0%.

A particularly preferable addition ratio is 2.0% or less.

If it is less than 0.5%, no significant increase in hardness can be expected; 3.
If it is added in an amount of 0% or more, it becomes too hard, impairing rolling properties and reducing corrosion resistance.

Furthermore, the effect of O and/or Mg on hardness is produced by adding Or at the same time, and O and/or Mg alone cannot be expected to have the effect of increasing hardness at high temperatures.

In other words, when Ou and/or Mg are added to AI, the increase in hardness during rolling is greater (even at the same rolling rate, the increase in hardness is more pronounced than in AI materials with other elements added). However, it easily softens when heated to nearly 200°C and cannot be expected to maintain high-temperature hardness.

On the other hand, when Or, Ou, and/or Mg are added simultaneously, the hardness, which increases during rolling due to the effect of adding Ou and/or Mg, does not decrease much due to the effect of adding Or even during annealing.

Therefore, an AlSn-based alloy with high hardness can be obtained, and the hardness does not decrease significantly even at high temperatures unlike conventional alloys of this type.

Furthermore, the third invention of the present invention is based on the first invention, that is, 3.5 to 35% Sn and 0.1 to 1.0% Or,
One or more of W, Ce, Nb, V, Ba, Oa, etc. is added to the composition of 1 to 10% and the balance of AI, Pb
tBi t In, one or more types of TI, excluding 0 and 9
It improves the properties of Sn as a lubricating metal.

The effects of Pb, Bt, In, and TI are observed when they are added together with Or.

In other words, adding these elements to Al-Sn alloys has been thought of and has been done in some cases, but if these elements are added alone, they will not be alloyed into Al-Sn alloys. Therefore, the disadvantage that the melting point of Sn becomes low cannot be avoided.

For this reason, in conventional AlSn-based alloys, Sn melts and moves easily at low temperatures, and as a result, it tends to grow into coarse Sn grains.
If this is used as a bearing, it may partially melt and peel off during continuous high-load operation.

On the other hand, as in the present invention, if the Sn grains are made finer by adding Or and the structure is maintained even at high temperatures, Pb.

Adding one or more types of B it I n t T l can improve the lubricity of Sn without causing the above-mentioned adverse effects, and it can also be used for bearings that require high fatigue strength. Therefore, it is possible to improve not only fatigue resistance but also conformability.

P b t B i that can obtain such an effect
The amount of one or more types of t I n t T l added is 9% or less excluding zero, preferably about 15% or more with respect to the amount of Sn contained.

Note that the total amount of one or more of Pb, Bi, In, and TI may be 9% or less.

Furthermore, Sn and P b t B t t I n , T
The total amount of I added is preferably within 35%.

This Pb, Bi. One or more of In, TI,
Further, the same amount may be added to the alloy composition of the second invention.

This can result in less loss of high temperature hardness (and at the same time improve the lubricity of the sn).

The reason why this effect occurs is the same as described above.

AI bearing alloys with the above composition are mainly used as sliding bearings in internal combustion engines for automobiles, but in this case they are usually used by being pressure-bonded to a backing steel plate, and after this pressure-welding, annealing is performed to increase the adhesive strength. I am doing it.

However, as mentioned above, movement of the A1 grain boundary and Sn particles in the conventional Al-Sn alloy structure occurs, causing the Sn particles to become coarser, resulting in drawbacks such as a decrease in hardness and the elution of Sn particles. .

In contrast, in the present invention, A generated from the rolling and annealing steps is
Since the precipitates of the l0r intermetallic compound impede the movement of the A1 grain boundaries and inhibit the growth of the AI crystal grains, the above-mentioned adverse effects due to annealing do not occur. can increase the adhesive strength of

This also applies when the present alloy is placed under high temperatures comparable to annealing, so it also means that it can contribute to improving fatigue strength by preventing softening.

Furthermore, it has been recognized that it is effective in improving wear resistance.
It is particularly effective when used on spheroidal graphite cast iron shafts.

Next, the present invention will be explained by examples.

The following table shows the chemical composition values of alloys (1) to (16) according to the present invention and alloys (17) to (23) for comparison.

For alloys 1 to 16, the AI base metal is melted in a gas furnace, and then Al0r master alloy, AlCu master alloy, Al-Mg master alloy, AI-W master alloy, Al-Ce master alloy, Al-Nb master alloy, A'l-V master alloy, Al-Ba master alloy, AlCa
The master alloy etc. are melted according to the target components and finally Sn and P are melted.
b.Bi.

After adding IntTl, gas treatment was performed, and casting was performed in a mold, followed by rolling and annealing (350
℃) was repeated to prepare samples, and the high-temperature hardness was measured.

Next, this sample was further rolled, and then these alloys and a backing steel plate were pressure-welded to form a bimetallic material, which was annealed and processed into a flat bearing, and a dynamic load fatigue test was conducted.

For Alloys 17 to 23, comparative alloys were prepared using the same manufacturing method as the above-mentioned alloys and used as samples, and the same tests were conducted.

However, Alloy 17.18 also contains Or and Cu.

FIG. 1 shows the results of measuring the hardness of Alloys 1 to 23 at high temperatures using Witzkers hardness.

As is clear from these graphs, 1 to 1 according to the present invention
Compared to Comparative Alloys 11 to 23, Alloy No. 16 has higher hardness in all humidity regions (Also, in comparison with Comparative Alloy 20, Alloy 20 may have higher hardness in the low temperature region; In contrast to Alloys 1 to 18 of the present invention, the hardness of Alloys 1 to 18 of the present invention decreases gradually as the temperature rises, and therefore the bearing condition is less likely to change due to changes in temperature. There is an effect that it can be done.

In particular, alloys to which Ou and/or Mg are added,
It was observed that the hardness was considerably higher than that without addition in the entire temperature range, and the hardness did not decrease with temperature rise compared to Alloy 20 (particularly high hardness was maintained even at a humidity of 200°C).

This is clearly an effect of adding Ou and/or Mg.

Further, from above the alloy structure, alloys 1 to 1 according to the present invention
In No. 6, no coarsening of Sn particles was observed even after annealing after joining with the backing steel plate.

Figure 2 shows alloys 3, 7, and 11 of the present invention and alloy 2 of the comparative material.
The graph shows the results of a dynamic load bearing fatigue test using No. 2 and No. 23 as representatives, but results showing similar trends have been obtained for other alloys as well.

In this test, the shaft rotation speed was 300 Or, 90 m long, 8550 hardened material was used as the shaft material, and under forced lubrication at a constant oil temperature, the fatigue resistance was varied under conditions of 107 stress repetitions, which are known to the fatigue state of steel materials, and the oil temperature was varied. This is a measurement of surface pressure.

As is clear from this graph, alloys 3 and 7. For both IL22 and 23, the fatigue resistance surface pressure decreases as the temperature increases, but the degree of decrease in the fatigue resistance surface pressure of alloys 3, 7, and 11 according to the present invention is not as large as that of comparative alloys 22 and 23, and 3,7,
11 and alloys 22 and 23, the difference in fatigue resistance surface pressure on the low temperature side is not that large (although there is no difference in fatigue resistance surface pressure on the high temperature side, alloys 3, 7,
It is clearly seen that alloy No. 11 outperforms alloy 22.23.

Note that FIG. 2 represents alloys according to the present invention; Alloy 3.
7, 11, and 22°23 are listed as representative alloys for comparison, but results showing similar trends have been obtained for other alloys as well.

Further, FIG. 3 shows alloy 7 according to the present invention and conventional alloy 22,
and Comparative Alloy 18 are graphs showing the results of measuring changes in friction torque when the load is increased.

In this experiment, the shaft rotation speed was 100 Or, 90 m1, 8550 hardened material was used as the shaft material, and the situation was measured using an oscillograph while increasing the load under forced lubrication at a constant oil well (140° C.).

According to this graph, in the conventional alloy 22, the friction torque increases with a large fluctuation accompanied by a peak every time the load is increased, and in the alloy 18, there is no large fluctuation accompanied by a peak, and the friction torque fluctuates smoothly. However, when the load stops increasing, a chevron-shaped friction torque fluctuation occurs.

On the other hand, in Alloy 7 of the present invention, the friction torque increases extremely smoothly following the increase in load, and no harmful friction torque fluctuations occur.

This shows that the alloy of the present invention has excellent conformability and is less prone to seizure.

In other words, the peak waveform with large fluctuations seen in conventional Alloy 22 means that the oil film on the sliding surface is partially destroyed, solid contact occurs, and if this is repeated, total destruction (seizure) will occur. Alloy 1 of the present invention, which does not produce such corrugations, has high conformability and seizure load resistance.

In addition, in the alloy composition according to the present invention, it goes without saying that the AI contains impurities that cannot be avoided by ordinary refining techniques.

Next, FIG. 4 shows the results of a friction test conducted on alloys 3, 6, and 10 according to the present invention and comparative alloys 17, 18, and 22.

In this experiment, the shaft rotation speed was 100 Or-p-m, 8550 hardened material was used as the shaft material, the shaft surface roughness was 1 μm, and the load was increased under forced lubrication in a constant oil lake (12o℃). 3 is a graph showing the results of measuring changes in the amount of wear in different cases.

According to this graph, compared to alloys 17, 1B, and 22, which are comparative materials, 3, 6, and 10, which have added Oe, W, etc., show extremely low wear amount, indicating excellent wear resistance. .

This is recognized to be the effect of W, Oe, Nb, VyBa7Ca, etc.

Next, FIG. 5 shows an experiment similar to that of FIG. 4 conducted using spheroidal graphite cast iron as the shaft material.

Compared to the case of the steel shaft in FIG. 4, the alloy 3.6 according to the invention
, 10 showed a large difference in wear amount from the comparative alloys 17 and 18°22, and W.

The effect of improving wear resistance by adding Oe, Nb, VyBa, Oa, etc. is more obvious when a spheroidal graphite cast iron shaft is used than when a steel shaft is used.

Alternatively, if a steel shaft with increased shaft roughness is used, the effect of improving wear resistance will become more obvious.

Next, FIG. 6 shows the results of a seizure test conducted on alloys 3, 6, and 10 according to the present invention and comparative alloys 17, 18, and 22.

In this experiment, the shaft rotation speed was 100 Or-p-rn, a spheroidal graphite cast iron shaft was used as the shaft material, and the load (static load) up to seizure was measured under forced lubrication at a constant oil well (140°C). Alloys 3, 6, and 10 of the present invention have W and Oe compared to comparative alloys 17, 1B, and 22.

It is recognized that alloy 3.6°10 to which Nb, V, Ba, Oa, etc. are added has a high seizure surface pressure.

Among them, alloys 6 and 10 to which Pb and Bi are added exhibit excellent seizure resistance.

As described above, the AlSn-based bearing alloy according to the present invention improves hardness by adding Or, prevents a decrease in high-temperature hardness, prevents coarsening of Sn particles, improves fatigue resistance through these, improves W
In addition to improving wear resistance by adding , Oe, Nb, V, BayCa, etc., especially when using spheroidal graphite cast iron or shafts with large shaft roughness, it also improves wear resistance and seizure resistance. Pb and B that are effective when added
i.

In? T I can improve conformability and seizure resistance, and further improve Cu and/or M
If g is added, the strength of the gold mud will be further improved.

In addition, since rolling annealing after pressure welding with the backing steel plate can be carried out at high temperature and for a long time, the performance of the alloy is not degraded (adhesion between the two can be improved).

The symbols for each element used in the text are as follows.AI
(aluminum), Sn (tin), Or (chromium), O
u (copper), Mg (magnesium), Pb (lead), Bi (
bismuth), In (indium), Si (silicon), T
I (thallium), W (tungsten), C3e (selenium), Nb (niobium), ■ (vanadium), Ba (barium), Ca (calcium).

[Brief explanation of drawings]

FIG. 1 is a graph plotting changes in hardness with changes in hot water temperature between an AlSn-based bearing alloy according to the present invention and a comparative bearing alloy of the same type. Figure 2 is the same (a graph plotting changes in fatigue resistance surface pressure). Figure 3 is the same (a graph showing changes in friction torque as the load is increased. Figure 4 is a graph plotting changes in friction torque when the load is increased. A graph showing changes in the amount of wear when the load on the shaft is similarly increased. Figure 5 is a graph showing the amount of wear on the spheroidal graphite cast iron material. Figure 6 is a graph showing the amount of wear on the spheroidal graphite cast iron shaft. It is a graph showing the seizure surface pressure against

Claims (1)

[Claims] 1 S n 3.5-35% by weight percentage, Oro, 1
~10%, one or more of W, Oe, Nb, V, BayOa in a total amount of 1 to 10% or less, and the balance essentially consisting of AI. 2 Sn3.5-35% by weight percentage, Oro, 1-1
Cu and (
or) an Al-8n bearing alloy consisting of 3.0% or less Mg (not including 0) and the balance essentially consisting of A1. 3 Sn 3.5-35% Oro, 1 by weight percentage
~IO%, one or more of W, Oe, Nb, V, Ba, Ca in a total amount of 1 to 10% or less, Pb,
9% of one or more of Bt, In, '['l
An Al-8n bearing alloy in which the following (excluding 0) and the remainder essentially consist of AI. 4 Sn 3.5-3.5% in weight percentage, Oro,
1-1.0%, W, Ce, Nb, V, BayOa 1
Species or two or more species in total amount of 1 to 10% or less, P b
, B i , I n , T I or more at 9% or less (not including 0), Ou and/or Mg
3% or less (excluding 0), and the remainder essentially A6
An AgSn-based bearing alloy consisting of