JPS582577B2 - aluminum bearing alloy - Google Patents

Description

【発明の詳細な説明】 本発明は、高温状態におけるＳｎ（スズ）粒子の成長お
よび硬さの低下が少なく、耐疲労性に優れかつ耐摩耗性
に優れたアルミニウム（Ａｌ）軸受合金に関するもので
、特に鋳造後数回の圧延と焼鈍を行なった後使用する場
合に好適な合金を提供するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum (Al) bearing alloy that exhibits less growth of Sn (tin) particles and less decrease in hardness in high-temperature conditions, has excellent fatigue resistance, and has excellent wear resistance. In particular, the present invention provides an alloy suitable for use after several rounds of rolling and annealing after casting.

従来のアルミニウム軸受合金としては、主としてＡｌ−
Ｓｎ系合金、たとえばＡｌ−Ｓｎ（２０％）−Ｃｕ（銅
）１％、Ａｌ−Ｓｎ（２０％）−Ｐｂ（鉛）３％−Ｃｕ
（１％）−Ｓｉ（ケイ素）３％等が使用されているが、
この合金を自動車用内燃機関の軸受に使用した場合、内
燃機関の高負荷運転が継続したとき等に短時間で疲労破
壊の起ることがあった。Conventional aluminum bearing alloys are mainly Al-
Sn-based alloys, such as Al-Sn (20%)-Cu (copper) 1%, Al-Sn (20%)-Pb (lead) 3%-Cu
(1%)-Si (silicon) 3% etc. are used,
When this alloy is used in bearings for automobile internal combustion engines, fatigue failure may occur in a short period of time, such as when the internal combustion engine continues to operate under high load.

これは内燃機関内のオイルが高負荷連続運転時に特に高
温となり、たとえばオイルパン内のオイルの温度は１３
０℃〜１５０℃にも達するため、軸受はそのすべり面に
おいてかなり高温度になることが予想され、この結果従
来のＡｌ−Ｓｎ系合金では高温下で硬さが急激に低下し
てＳｎの溶融や移動がおこり、このことが疲労強度も低
下することの原因であると考えられる。This is because the oil in the internal combustion engine becomes particularly hot during continuous high-load operation; for example, the temperature of the oil in the oil pan is 13.
Since the temperature reaches 0°C to 150°C, it is expected that the sliding surface of the bearing will reach a considerably high temperature.As a result, in conventional Al-Sn alloys, the hardness rapidly decreases at high temperatures and the Sn melts. This is thought to be the cause of the decrease in fatigue strength.

本発明の発明者等が高温下で硬さの高い合金やＳｎの動
きにくい合金を内燃機関軸受の形状に加工し、高温油下
で動荷重疲労試験を行なった結果、疲労強度の向上が認
められたことは上記考察を裏付けている。The inventors of the present invention fabricated an alloy with high hardness or an alloy in which Sn does not easily move under high temperatures into the shape of an internal combustion engine bearing, and conducted a dynamic load fatigue test under high temperature oil, and as a result, improved fatigue strength was found. The above findings support the above considerations.

また、以上の高温硬さの低下に基く疲労強度の低下とは
別に、従来のＡｌ−Ｓｎ系合金では合金組織におけるＳ
ｎ粒子の粗大化も疲労強度の低下の原因となっている。In addition to the decrease in fatigue strength due to the decrease in high-temperature hardness, in conventional Al-Sn alloys, S
Coarsening of n-particles also causes a decrease in fatigue strength.

すなわち、アルミニウム軸受合金は、Ａｌ−Ｓｎ系合金
を裏金鋼板に圧接して形成するものであるが、両金属の
接着強度を増すために圧接後これを焼鈍する工程が不可
欠であり、一般的にはこの焼鈍は、Ａｌ−Ｆｅの金属間
化合物の析出する温度（約４７５℃）以下で、温度が高
く時間が長い程接着強度が大となる。In other words, aluminum bearing alloys are formed by pressure-welding an Al-Sn alloy to a backing steel plate, but in order to increase the adhesive strength of both metals, it is essential to anneal the alloy after pressure-welding, and generally This annealing is performed at a temperature below the temperature at which the Al-Fe intermetallic compound precipitates (approximately 475° C.), and the higher the temperature and the longer the time, the greater the adhesive strength.

ところが、従来のＡｌ−Ｓｎ系合金は焼鈍によって高温
下におかれると、合金組織中でＡｌ粒界およびＳｎ粒子
の移動が起り、この結果時間の経過とともにＳｎ粒子の
粗大化が進行してしまうという欠点があった。However, when conventional Al-Sn alloys are exposed to high temperatures during annealing, Al grain boundaries and Sn particles move within the alloy structure, resulting in coarsening of the Sn particles over time. There was a drawback.

つまり従来のアルミニウム軸受合金では、裏金鋼板との
接着強度を増すために焼鈍すれば、Ｓｎ粒子の粗大化を
招き、この粗大化はＡＩ−Ｓｎ系合金の疲労強度を低下
させる原因となっている。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 is the cause of lowering the fatigue strength of the AI-Sn alloy. .

本発明の発明者等は、Ａｌ−Ｓｎ系合金に種々の添加元
素を加えてその高温硬さ、疲労強度についての改良を進
めた結果、既にＡｌにＳｎの他所要量のＣｒ（クロム）
またはＺｒ（ジルコニウム）およびＣｕ等を加えた合金
を開発し、特許出願（特願昭５２−２６９０号つしてい
る。The inventors of the present invention have added various additive elements to Al-Sn alloys to improve their high-temperature hardness and fatigue strength.
Alternatively, we have developed an alloy containing Zr (zirconium), Cu, etc., and have filed a patent application (Japanese Patent Application No. 52-2690).

さらにＳｎ、ＣｒおよびＣｕ等の他、ｐｂまたはＩｎ（
インジウム）を加え、耐疲労性を同等に維持したまま特
になじみ性を向上させた合金を開発し、特許出願（特願
昭５２−１８２５５）している。Furthermore, in addition to Sn, Cr, Cu, etc., pb or In(
Indium) was added to develop an alloy with particularly improved conformability while maintaining the same fatigue resistance, and a patent application (Japanese Patent Application No. 52-18255) was filed.

本発明は、さらに研究を進めた結果、Ａｌ−Ｓｎ系合金
に特にＣｒの含有量を増すことにより、相手材質を選ば
ずに耐摩耗性を著しく向上させることができる材料を見
出してなされたものである。The present invention was achieved by further research and the discovery of a material that can significantly improve wear resistance regardless of the mating material by increasing the Cr content in an Al-Sn alloy. It is.

本発明のＡｌ−Ｓｎ系合金は、基本的には重量％で３５
％〜３５％のＳｎと、１．０％を越え７０％のＣｒとか
らなるＡＩ−Ｓｎ系合金を基本とし、これにＣｕおよび
（または）Ｍｇ（マグネシウム）３０％以下（０を含ま
ず）、９％以下（０を含まず）のｐｂ、Ｉｎ、Ｂｉ（ビ
スマス）の少なくとも１種とから構成され、かつ、Ｓｎ
量は添加元素中最大となるようにしたことを特徴とする
もので、従来のＡＩ−Ｓｎ系合金に比べＣｒ、Ｐｂ、Ｂ
ｉ、Ｉｎを加えたことによってＳｎが微細化されるとと
もになじみ性が向上し、加えて硬さが上昇し、特に高温
状態におけるＳｎの移動と成長がほとんどないことが認
められた。The Al-Sn alloy of the present invention is basically 35% by weight.
Based on an AI-Sn alloy consisting of % to 35% Sn and more than 1.0% to 70% Cr, plus Cu and/or Mg (magnesium) 30% or less (not including 0) , 9% or less (not including 0) of at least one of pb, In, and Bi (bismuth), and Sn
The amount of Cr, Pb, and B is the largest among the added elements, compared to conventional AI-Sn alloys.
It was observed that by adding i, In, Sn was made finer and conformability improved, and in addition, hardness increased, and there was almost no movement or growth of Sn, especially at high temperatures.

また高温硬さの低下も少ない。Also, there is little decrease in high temperature hardness.

さらに動荷重疲労試験を行なったところ、高油温下での
疲労強度の向上が確認された。Furthermore, when a dynamic load fatigue test was conducted, it was confirmed that the fatigue strength was improved under high oil temperatures.

また、特に軸受の摺動性能に大きな影響を及ぼす相手材
質、すなわち軸材質を選ばず、どんな材料であっても充
分な耐摩耗性を持つこども確認された。In addition, it has been confirmed that the material has sufficient wear resistance regardless of the material of the bearing, that is, the material of the shaft, which has a particularly large effect on the sliding performance of the bearing.

Ｓｎの含有量を重量％で３５〜３５％に限定した理由は
、Ｓｎは潤滑を主目的として添加される元素であるが、
これを３５％以上添加するとなじみ性、潤滑性は向上す
るが硬さが低下し、これが３．５％以下では逆に軸受台
金としてはなじみ性等に劣るからである。The reason for limiting the Sn content to 35 to 35% by weight is that Sn is an element added primarily for the purpose of lubrication, but
This is because if it is added in an amount of 35% or more, the conformability and lubricity improve, but the hardness decreases, and if it is less than 3.5%, the conformability as a bearing base metal is inferior.

なお、このＳｎの添加量はＳｎを弧立分散させるために
、従来のＡｌ−Ｓｎ系合金では１５％程度が上限とされ
ており、その理由はこれを１５％以上添加すると合金中
のＳｎ粒子がＡｌ中に弧立して分散できなくなり連続状
態で存在し始めるため、硬さが低下するからとされてい
たが、本発明では後述する他の元素の添加効果によって
これを３５％迄添加した場合でもＳｎ粒子が弧立分散し
実用上支障がなくなった。The upper limit of the amount of Sn added in conventional Al-Sn alloys is about 15% in order to disperse Sn vertically, and the reason is that if more than 15% is added, the Sn particles in the alloy It was believed that this was because the hardness decreased because the aluminum could no longer be dispersed vertically in the aluminum and began to exist in a continuous state, but in the present invention, it was added up to 35% due to the effects of adding other elements, which will be described later. Even in this case, the Sn particles were dispersed vertically and there was no problem in practical use.

また、Ｓｎの添加量を３．５〜３５％の範囲でどのよう
に定めるかは、用途に応じ適宜決定されるべきものであ
るが、一般的には軸受に加わる荷重（負荷）の大なると
きはＳｎ量を少なく、荷重の小なるときはＳｎ量を多く
すると良い。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 generally speaking, it is When the load is small, it is better to reduce the amount of Sn, and when the load is small, it is better to increase the amount of Sn.

また別の観点からは、焼付きが懸念される状態で使用さ
れるときはＳｎ量を多く、この心配のないときはＳｎ量
を少なくするのが良い。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.

しかし最近は高油温により軸受が高温になり、これが原
因で軸受が変形し焼付、疲労を起すことが問題であるの
で、高温での変形が少ないという点からＳｎ量を定める
必要もある。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.

Ｃｒは硬さの上昇と高温時の軟化を防ぐ点、および焼鈍
によってもＳｎ粒子の粗大化を招かないという点、また
相手材質を選ばずに充分な耐摩耗性茶持つという点につ
いて特に添加効果が高い。Cr is particularly effective as an additive in that it prevents increases in hardness and softening at high temperatures, that it does not cause coarsening of Sn particles even during annealing, and that it maintains sufficient wear resistance regardless of the material used. is high.

まず硬さの上昇と高温時の軟化防止について述べると、
このＣｒの添加量が重量で１．０％以下では高温硬さの
改良は期待できるが耐摩耗件の向上が望めない。First, let's talk about increasing hardness and preventing softening at high temperatures.
If the amount of Cr added is less than 1.0% by weight, improvement in high temperature hardness can be expected, but improvement in wear resistance cannot be expected.

７．０％以上添加するとＣｒＡｌ等のＡｌ−Ｃｒ金属間
化合物が析出し過ぎ、軸受合金としては硬くなり過ぎ、
耐摩耗性は向上してもなじみ性が極端に低下し過ぎるこ
とからその添加量を１０を越え７．０％に限定したもの
である。If 7.0% or more is added, Al-Cr intermetallic compounds such as CrAl will precipitate too much, making the bearing alloy too hard.
Even if the wear resistance is improved, the conformability is extremely reduced, so the amount added is limited to more than 10% and 7.0%.

この高温硬さの向上についてさらに詳述すると、Ｃｒは
ＡＩ中に固溶することによってＡＩの再結晶温度を上げ
、かつ固溶すること自体でＡＩ地の硬さを上昇させるが
、これと同時に数回の圧延によっても鋳造時に比して硬
さが上昇する。To explain this improvement in high-temperature hardness in more detail, Cr increases the recrystallization temperature of AI by solid solution in AI, and the solid solution itself increases the hardness of the AI base. Even by rolling several times, the hardness increases compared to when it is cast.

再結晶温度を上げることは内燃機関の軸受がさらされる
高温領域でも安定した機械的性質を維持させるために効
果があり、特に硬さについては、高温下での硬さの低下
を少なくして高温領域での軸受の軟化を防ぐことができ
、ひいては疲労強度の向上をもたらす。Increasing the recrystallization temperature is effective in maintaining stable mechanical properties even in the high temperature range to which internal combustion engine bearings are exposed. This can prevent the bearing from softening in this region, which in turn improves fatigue strength.

また固溶限を過ぎて析出するＡｌ−Ｃｒの金属間化合物
は、ウイツカース硬さで約３７０を示しこのためこの化
合物が分散析出することは高温硬さの維持を助け、これ
が適量分散することは良い効果を生ずる。In addition, the Al-Cr intermetallic compound that precipitates beyond the solid solubility limit has a Utzkers hardness of approximately 370. Therefore, the dispersion and precipitation of this compound helps maintain high-temperature hardness, and dispersion of this compound in an appropriate amount is essential. produce good effects.

次にＣｒ添加によるＳｎ粒子の粗大化阻止効果について
述べる。Next, the effect of inhibiting the coarsening of Sn particles by adding Cr will be described.

Ｓｎ粒子の粗大化はＡｌ−Ｓｎ系合金が高温下におかれ
た場合Ａｌ粒界およびＳｎ粒子の移動が起るために生ず
る現象であるが、Ｃｒは上記のようにＡｌ−Ｃｒの金属
間化合物の析出物を作り、この析出物がＡｌ地金中に細
かく分散して存在するため、この金属間化合物が直接的
にはＡｌ粒界の移動を妨げ、同時にＡｌ結晶粒の成長を
妨げてＳｎ粒子の移動、つまりＳｎ粒子の粗大化を防ぐ
からであると考えられる。The coarsening of Sn particles is a phenomenon that occurs due to the movement of Al grain boundaries and Sn particles when an Al-Sn alloy is exposed to high temperatures, but as mentioned above, Cr Precipitates of compounds are formed and these precipitates are finely dispersed in the Al metal, so these intermetallic compounds directly prevent the movement of Al grain boundaries and at the same time prevent the growth of Al crystal grains. This is thought to be because it prevents the movement of Sn particles, that is, the coarsening of Sn particles.

このことは、圧延、焼鈍等により微細化されたＳｎ粒子
を、そのまま保つことにつながり、前記種々の効果を持
つのである。This leads to keeping the Sn particles that have been refined by rolling, annealing, etc. as they are, and has the various effects mentioned above.

そしてこのような現象は比較的Ｓｎ量の多い場合（約１
０％以上）において、またより顕著な効果はＳｎが連続
して存在しはじめる約１５％前後以上において効果があ
る。This phenomenon occurs when the amount of Sn is relatively large (approximately 1
0% or more), and a more significant effect occurs at about 15% or more, where Sn begins to exist continuously.

しかし、Ｓｎ量が１０％以下であってもその使用条件、
用途によっては上記Ｃｒの添加による効果が充分必要と
されることはもちろんである。However, even if the Sn amount is 10% or less, the usage conditions
It goes without saying that the effects of the addition of Cr may be required depending on the application.

また、Ｓｎ粒子が微細のまま保持されてＡｌ地金中に存
在するということは、同時に２３２℃という低い融点を
もつＳｎ粒子の高温下での溶出現象を防止するためにも
効果的であると考えられ、この観点からしても硬さの低
下防止の効果が背首される。Furthermore, the fact that the Sn particles remain fine and exist in the Al base 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 significant.

なお、以上は焼鈍に関してＳｎ粒子の粗大化阻止効果を
述べたものであるが、以上の効果は本軸受材料の使用環
境が焼鈍に匹敵する高温下である場合にもそのまま妥当
し、したがって軟化の防止を通じ疲労強度の向上を図る
、ことができる。The above is a description of the effect of inhibiting the coarsening of Sn particles during annealing, but the above effect also applies when the bearing material is used in a high-temperature environment comparable to that of annealing. It is possible to improve fatigue strength through prevention.

次に、Ｃｒ添加による耐摩耗性向上効果について述べる
。Next, the effect of improving wear resistance by adding Cr will be described.

ＣｒはＡｌ地金中において上記のようにＡｌ−Ｃｒの金
属間化合物の析出物を作るが、この化合物は、ウイツカ
ース硬さで約３７０を示し、非常に硬い析出物であるの
で軸との摩擦による軸受の摩耗をこの析出物により著し
く減少させることができ、これが適量分散することは良
い効果を生ずる。Cr forms a precipitate of an Al-Cr intermetallic compound in the Al base metal as described above, but this compound has a Utzkers hardness of about 370 and is a very hard precipitate, so it is difficult to cause friction with the shaft. This precipitate can significantly reduce the wear of bearings caused by oxidation, and dispersing an appropriate amount of this precipitate produces a good effect.

ここに適量の範囲は、前述のようにＣｒが７．０％以下
を意味し、この範囲であれば上記折出物は均一に分散し
、なじみ性等他に悪影響を与えることなく耐摩耗性を向
上させる効果が得られる。As mentioned above, the appropriate amount range here means 7.0% or less of Cr, and within this range, the above-mentioned precipitates will be uniformly dispersed, and the wear resistance will be improved without adversely affecting other properties such as conformability. The effect of improving this can be obtained.

加えてＡｌ−Ｃｒ析出物は次のような効果を持つ。In addition, Al-Cr precipitates have the following effects.

すなわち軸受にとって相手材質は軸受性能を大きく左右
し、たとえば従来のＡｌ−Ｓｎ系軸受と球状黒鉛鋳鉄軸
と組合せて使用すると焼付性、耐摩耗性等についての軸
受性能を著しく阻害する。In other words, the mating material for a bearing greatly influences the bearing performance, and for example, when a conventional Al-Sn bearing is used in combination with a spheroidal graphite cast iron shaft, the bearing performance in terms of seizure resistance, wear resistance, etc. is significantly impaired.

そしてまた昨今、鋼軸に替わり加工上安価な球状黒鉛鋳
鉄軸が多く使われるようになってきた。Recently, spheroidal graphite cast iron shafts, which are cheaper to process, have been increasingly used in place of steel shafts.

ところが球状黒鉛鋳鉄は軟質な黒鉛が鉄地の中に点在し
ていて、このためこの軸を研削するとその黒鉛の周囲に
鋭い刃形を持った研摩パリが発生する。However, in spheroidal graphite cast iron, soft graphite is dotted within the iron base, and for this reason, when this shaft is ground, grinding chips with sharp edges are generated around the graphite.

このような研摩パリの発生した軸を相手に油膜厚さと軸
および軸受表面粗さとが同じになる程度の高荷重下で軸
受を摺動させると、このパリにより軸より軟かい軸受面
は切削されることになり、この状況が進行すると軸受表
面精度が粗くなったり軸の軸受とのクリアランスが増大
したりし、しいては油膜圧力が構成されなくなったり、
油膜破断により油膜が構成されなくなったりして、その
結果軸と軸受との直接接触つまり金属接触がより多く起
り焼付に至る。When a bearing is slid against a shaft with such abrasive chips under such a high load that the oil film thickness is the same as the surface roughness of the shaft and bearing, the bearing surface, which is softer than the shaft, will be cut by these chips. As this situation progresses, the bearing surface accuracy becomes rough, the clearance between the shaft and the bearing increases, and the oil film pressure is no longer formed.
When the oil film breaks, the oil film is no longer formed, and as a result, direct contact between the shaft and the bearing, that is, metal contact, occurs more frequently, leading to seizure.

ところが本発明に係る合金は球状黒鉛鋳鉄軸のパリより
も硬いＡｌ−Ｃｒの析出物をＡｌ地中に分散存在させて
、このＡｌ−Ｃｒ析出物により球状黒鉛鋳鉄軸の研摩パ
リを取り去る効果およびＡｌ−Ｃｒの析出物が移着、凝
着現象を起しにくくする効果をも持たせてあり、これに
より軸受表面の摩耗の進行は比較的短時間で抑えられ安
定した油膜が構成されるようになり、この結果球状黒鉛
鋳鉄軸に対して特に耐摩耗性、耐焼付性を向上させる。However, the alloy according to the present invention has the effect of dispersing Al-Cr precipitates that are harder than the pars of the spheroidal graphite cast iron shaft in the Al ground, and has the effect of removing the polishing pars of the spheroidal graphite cast iron shaft with these Al-Cr precipitates. It also has the effect of making it difficult for Al-Cr precipitates to migrate and adhere, 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, wear resistance and seizure resistance are particularly improved for spheroidal graphite cast iron shafts.

次に本発明は、上記組成に加えてＣｕ または（および
）Ｍｇを重量％で３％以下加えたものである。Next, in the present invention, Cu or (and) Mg is added in an amount of 3% or less by weight in addition to the above composition.

このうちＣｕを用いる場合にはその添加量を３％以下と
する。Among these, when Cu is used, the amount added is 3% or less.

３％以下添加すると硬さは向上するがＣｕの増加と共に
圧延性、耐斡性が低下し好ましくないからである。This is because adding 3% or less of Cu improves hardness, but as Cu increases, rollability and punching resistance decrease, which is not preferable.

ここでより好ましい添加割合は２．０以下である。Here, a more preferable addition ratio is 2.0 or less.

またＭｇについては、これを３％以上添加すると、硬さ
は向上するが圧延による硬さ上昇が大きくなり過ぎて充
分な圧延ができなくなり、このため微細なＳｎ組織を得
ることが困難になる。As for Mg, if it is added in an amount of 3% or more, the hardness improves, but the increase in hardness due to rolling becomes too large, making it impossible to perform sufficient rolling, making it difficult to obtain a fine Sn structure.

また焼鈍時にＡｌに固溶していたＭｇが析出しやすく余
分に添加された量は析出してしまうため、固溶によるＡ
ｌ地の強化は期待できない。In addition, Mg that was dissolved in Al during annealing is likely to precipitate, and the excess amount added will precipitate.
We cannot expect to strengthen our base.

ここでより好ましい添加割合は２．０以下である。Here, a more preferable addition ratio is 2.0 or less.

このＣｕとＭｇの上記効果はＣｒと同時に添加して生ず
るもので、ＣｕまたはＭｇ単独では高温下での硬さの上
昇の効果が期待できない。The above-mentioned effect of Cu and Mg occurs when Cr is added at the same time, and Cu or Mg alone cannot be expected to have the effect of increasing hardness at high temperatures.

すなわちＣｕまたはＭｇはＡｌ中に添加した場合に圧延
時の硬さの上昇が大きく同一圧延率でも他の元素を添加
したＡｌ材料に比し、硬さの上昇は顕著であるが、２０
０℃近く迄加熱すると容易に軟化し、高温硬さの維持は
期待できない。In other words, when Cu or Mg is added to Al, the hardness increases significantly during rolling, and even at the same rolling rate, the increase in hardness is remarkable compared to Al materials with other elements added.
It easily softens when heated to near 0°C, and cannot be expected to maintain high temperature hardness.

これに対してＣｒとＣｕ またはＭｇを同時に添加する
と、ＣｕまたはＭｇの添加効果によって圧延時に高くな
った硬さが、焼鈍をしてもＣｒの添加効果、すなわち再
結晶温度の上昇によりあまり低下しない。On the other hand, when Cr and Cu or Mg are added at the same time, the hardness that increases during rolling due to the effect of adding Cu or Mg does not decrease much even after annealing due to the effect of adding Cr, that is, the increase in recrystallization temperature. .

この硬さは高温時においても保たれ、従来合金に比べて
高温強度のある合金となり、ひいては疲労強度の向上に
もつながる。This hardness is maintained even at high temperatures, resulting in an alloy with higher high-temperature strength than conventional alloys, which in turn leads to improved fatigue strength.

なおＣｕとＭｇを同時に添加する場合は、その合計量は
３％以内とし、その内Ｃｕは２％以内とすることが好ま
しい。Note that when Cu and Mg are added at the same time, the total amount thereof is preferably within 3%, of which Cu is preferably within 2%.

次にＰｂ，Ｂｉ、Ｉｎのうち少なくとも１種添加するこ
とはＳｎの潤滑金属としての性質を改良するためであり
、Ｃｒと一緒に添加したときに効果が認められる。Next, the addition of at least one of Pb, Bi, and In is to improve the properties of Sn as a lubricating metal, and the effect is observed when it is added together with Cr.

従来Ａｌ−Ｓｎ系合金の中にこれらの元素を添加するこ
とは考えられ、また一部行なわれているが、これらの添
加元素を単独で加えるとＡｌ−Ｓｎ系合金の中へ合金化
されてしまうためＳｎの融点が低くなってしまうという
欠点が避けられない。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. Because of storage, the disadvantage that the melting point of Sn becomes low cannot be avoided.

このため従来のＡｌ−Ｓｎ系合金は低温でＳｎの溶融と
移動が起こり易くなる結果、粗大なＳｎ粒に成長しやす
く、これを軸受として使用すると、高負荷運転が連続し
たとき部分的に溶融し、ハクリすることもありうる。For this reason, in conventional Al-Sn alloys, Sn easily melts and moves at low temperatures, and as a result, it tends to grow into coarse Sn grains. However, it may peel off.

これに対し本発明のようにＣｒを加えることによってＳ
ｎ粒を微細化し、かつその組織を高温でも維持でぎるよ
うにしておくと、Ｐｂ，Ｂｉ、Ｉｎのうち少なくとも１
種を加えても上記のような幣害は生ぜずにＳｎの潤滑性
を改鋳することができ、高い疲労強度の必要とされる軸
受にも使用可能となり、さらに耐疲労性に加えてなじみ
性の向上も図ることができる。On the other hand, by adding Cr as in the present invention, S
By making the n grains fine and maintaining their structure even at high temperatures, at least one of Pb, Bi, and In
Even with the addition of seeds, the lubricity of Sn can be improved without causing the above-mentioned damage, making it possible to use it in bearings that require high fatigue strength. It is also possible to improve the

またさらに析出したＡｌ−Ｃｒ金属間化合物の軸受表面
に露出した表面に、Ｐｂ、Ｂｉ、Ｉｎの添加によって潤
滑性能が改善されたＳｎ系低融点金属が薄く被膜を形成
することにより、摩擦特性が改善される。Additionally, a thin film of Sn-based low melting point metal, whose lubricating performance has been improved by adding Pb, Bi, and In, is formed on the exposed surface of the bearing surface of the precipitated Al-Cr intermetallic compound, thereby improving frictional properties. Improved.

このような効果を得ることのできるＰｂ、Ｂｉ、Ｉｎの
うち少なくとも１種の添加量は９％以下（０を含まず）
であり、好ましくは含有Ｓｎ量に対し約１５％以下程度
がよい。The amount of at least one of Pb, Bi, and In that can obtain such effects is 9% or less (excluding 0)
The content is preferably about 15% or less based on the amount of Sn contained.

なおｐｂとＢｉとＩｎを合わせて９％以下としてもよい
。Note that the total amount of pb, Bi, and In may be 9% or less.

さらにＳｎとｐｂ、Ｂｉ、Ｉｎのうち少なくとも１種と
の合計添加量は３５％以内がよい。Furthermore, the total addition amount of Sn and at least one of pb, Bi, and In is preferably within 35%.

なおＡｌ中に潤滑金属を微細に存在させるためにＳｎ量
は添加示素の中では最も多くなければならない。Note that the amount of Sn must be the largest among the added atoms in order to allow the lubricating metal to exist finely in Al.

上記組織のＡｌ軸受合金は、主に車輌用内燃機関のすべ
り軸受として使用されるが、この場合裏金鋼板に圧接し
て用いるのが普通であり、この圧接後には接着強度を増
すために焼鈍を行なっている。Al bearing alloys with the above structure are mainly used as sliding bearings in internal combustion engines for vehicles, but in this case they are usually used by being pressure-bonded to a backing steel plate, and after this pressure-bonding, annealing is performed to increase the adhesive strength. I am doing it.

ところが前述のように従来のＡｌ−Ｓｎ系合金では圧延
後の数回に渡る焼鈍によって合金組織中のＡｌ粒界およ
びＳｎ粒子の移動が生じ、Ｓｎ粒子が粗大化するため、
硬さの低下、Ｓｎ粒子の溶出等の欠点が生じていた。However, as mentioned above, in conventional Al-Sn alloys, the Al grain boundaries and Sn particles in the alloy structure move due to several times of annealing after rolling, causing the Sn particles to become coarse.
There were drawbacks such as a decrease in hardness and elution of Sn particles.

これに対し本発明では、圧延、焼鈍の工程から生じるＡ
ｌ−Ｃｒ金属間化合物の析出物がＡｌ粒界の移動を妨げ
るとともにＡｌ結晶粒の成長を阻止するので、焼鈍によ
る上記悪影響の生ずることがなく、このため焼鈍温度を
上げてＡｌ−Ｓｎ系合金と裏金鋼板との接着強度を増す
ことができる。In contrast, in the present invention, A generated from the rolling and annealing steps is
Since the precipitates of the l-Cr intermetallic compound impede the movement of Al grain boundaries and inhibit the growth of Al crystal grains, the above-mentioned adverse effects due to annealing do not occur, and therefore the annealing temperature can be raised to improve the Al-Sn alloy. It is possible to increase the adhesive strength between the metal plate and the backing steel plate.

なおこのことは、本合金が焼鈍に匹敵する高温下に置か
れる場合にも、そのまま妥当するから、軟化の防止を通
じ疲労強度の向上に寄与できることも同時に意味してい
る。This also means that this alloy remains valid even when it is placed under high temperatures comparable to annealing, so it can contribute to improving fatigue strength by preventing softening.

次に実施例によって本発明を説明する。Next, the present invention will be explained by examples.

次表は本発明に係る合金１〜１７、比較材として合金１
８〜２１の化学成分値を示すものである。The following table shows alloys 1 to 17 according to the present invention, and alloy 1 as a comparative material.
It shows chemical component values from 8 to 21.

合金１から１７迄は、ガス炉においてＡｌ地金を溶解し
、次にＡｌ−Ｃｒ母合金やＡｌ−Ｃｕ母合金Ａｌ−Ｍｇ
母合金を目的成分に応じて溶解し最後にＳｎおよびｐｂ
等を添加したのち脱ガス処理をし、湯温７２０℃で金型
に鋳造を行なったものでその後圧延と焼鈍（３５０℃）
を繰り返して試料を作り、高温硬さ測定を行なった。Alloys 1 to 17 are obtained by melting Al base metal in a gas furnace, and then melting Al-Cr master alloy or Al-Cu master alloy Al-Mg.
The master alloy is melted according to the target components, and finally Sn and PB are melted.
etc., then degassed and cast into a mold at a hot water temperature of 720°C, then rolled and annealed (350°C).
Samples were prepared by repeating the steps, and high-temperature hardness measurements were performed.

次にこの試料をさらに圧延し、その後これらの合金と裏
金鋼板とを圧接してバイメタル材とし、これを焼鈍（３
８０℃）した後平面軸受に加工して動荷重疲労試験を行
なった。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 then annealed (3
80°C), it was processed into a flat bearing and subjected to a dynamic load fatigue test.

また合金１８〜２１は、比較の便宜のために従来の組成
の合金を上記合金と同一の製造法で作製して試料とし、
同一の試験を行なった。For convenience of comparison, Alloys 18 to 21 were prepared using the same manufacturing method as the above alloys, and used as samples.
An identical test was conducted.

第１図は、上記合金１ないし２１の高温下での硬さをヴ
イツカース硬度で測定した結果を示すものである。FIG. 1 shows the results of measuring the hardness of Alloys 1 to 21 at high temperatures using Witzkers hardness.

これらのグラフから明らかなように、本発明に係る合金
１〜１７は従来の合金１８〜２０に比してすべての温度
領域において硬度が高く、また従来の合金２１との比較
では、合金２１の方が低温度領域において硬度の高い場
合も存在するが、合金２１は温度の上昇と共に急激にそ
の硬度が低下するのに対し、本発明の合金１ないし１７
は温度上昇に伴う硬度低下の程度がゆるやかであり、し
たがって温度の変化に伴う軸受状態の変化を少なくでき
るという効果がある。As is clear from these graphs, alloys 1 to 17 according to the present invention have higher hardness in all temperature ranges than conventional alloys 18 to 20. Although there are cases where the hardness of Alloy 21 is higher in the low temperature range, the hardness of Alloy 21 decreases rapidly as the temperature rises, whereas Alloy 1 to 17 of the present invention
The hardness decreases slowly as the temperature rises, and therefore has the effect of reducing changes in the bearing condition due to changes in temperature.

また特にＰｂ、Ｂｉ、Ｉｎの他にＣｕまたは（および）
Ｍｇを添加した合金５〜１３，１６，１７は、全温度領
域において特に硬度の高いことが認められ、かつ合金２
１に比して温度上昇に伴う硬度低下が少なく特に温度２
００℃においても高い硬度を維持している。In addition to Pb, Bi, and In, Cu or (and)
Alloys 5 to 13, 16, and 17 to which Mg was added were found to have particularly high hardness in the entire temperature range, and alloy 2
Compared to 1, the hardness decreases with increasing temperature, especially at temperature 2.
It maintains high hardness even at 00°C.

これは明らかにＣｕ，Ｍｇを加えたことによる効果であ
る。This is clearly an effect of adding Cu and Mg.

また合金組織の上からは、本発明に係る合金１ないし１
７は、裏金鋼板との接合後の焼鈍を経ても、Ｓｎ粒子の
粗大化は認められなかった。Moreover, from above the alloy structure, alloys 1 to 1 according to the present invention
In No. 7, no coarsening of Sn particles was observed even after annealing after joining with the backing steel plate.

第２図は、本発明の合金２，５，９，１４，１６と従来
の合金１Ｂ，１９，２０について動荷重軸受疲労試験を
行なった結果を示す。FIG. 2 shows the results of a dynamic load bearing fatigue test conducted on alloys 2, 5, 9, 14, and 16 of the present invention and conventional alloys 1B, 19, and 20.

この試験は、軸回転数３０００ｒ．ｐ．ｍ、軸材として
Ｓ５５Ｃ焼入れ材を使用し、一定油温の強制潤滑下にお
いて、鉄鋼材料の疲労状況を知る１０７回応力繰り返し
条件で油温を異ならせて耐疲労面圧を測定したものであ
る。This test was conducted at a shaft rotation speed of 3000 r. p. m, S55C hardened material was used as the shaft material, and the fatigue resistance surface pressure was measured under forced lubrication at a constant oil temperature, under conditions of 107 stress repetitions, which determine the fatigue state of steel materials, and at different oil temperatures. .

このグラフから明らかなように合金２，５，９，１４，
１６，１８，１９，２０とも温度が高い程耐疲労面圧が
低下するが、本発明に係る合金２，５，９，１ ４，１
６は耐疲労面圧の低下の程度が従来の合金１８，１９，
２０程大きくなく、かつ合金２，５，９，１４，１６と
合金１８，１９，２０は低温側の耐疲労面圧での差はそ
れ程大きくないが、高温側の耐疲労面圧は合金２，５，
９，１４，１６が合金１８，１９，２０を凌駕している
ことが明瞭に認められる。As is clear from this graph, alloys 2, 5, 9, 14,
Alloys 16, 18, 19, and 20 have lower fatigue resistance as the temperature increases, but alloys 2, 5, 9, 1 4, 1 according to the present invention
6 has a lower fatigue resistance surface pressure than conventional alloys 18, 19,
20, and the difference in fatigue resistance surface pressure on the low temperature side between alloys 2, 5, 9, 14, 16 and alloys 18, 19, 20 is not that large, but the fatigue resistance surface pressure on the high temperature side is higher than that of alloy 2. ,5,
It is clearly seen that alloys 9, 14, and 16 outperform alloys 18, 19, and 20.

なお、第２図は本発明に係る合金を代表させて合金２，
５，９，１４，１６従来の合金を代表させて１８，１９
，２０を挙げたものであるが、他の合金も同様の傾向を
行す結果が得られている。In addition, FIG. 2 shows alloys 2 and 2 representing alloys according to the present invention.
5,9,14,16Representative of conventional alloys18,19
, 20, but similar results have been obtained for other alloys.

また次表は本発明に係る合金２，９，１２と従来の合金
１８，１９について焼付試験を行なったときの焼付荷重
を示すものである。Further, the following table shows the seizure loads when a seizure test was conducted on alloys 2, 9, and 12 according to the present invention and conventional alloys 18 and 19.

この実験は、軸回転数１０００ｒ．ｐ．ｍ、軸材として
Ｓ５５Ｃ焼入れ材を使用し、一定油温（１４０℃）の強
制潤滑下において、焼付に至る迄の荷重（静荷重）を測
定したものであって、本発明の合金２，９，１２は合金
１８，１９に比しはるかに優れた焼付荷重を示しており
、これはなじみ性を向上させる添加剤、すなわちＰｂ，
Ｂｉ、Ｉｎの効果であることが認められる。In this experiment, the shaft rotation speed was 1000 r. p. m, S55C hardened material was used as the shaft material, and the load (static load) up to seizure was measured under forced lubrication at a constant oil temperature (140 ° C.). Alloys 2 and 9 of the present invention , 12 shows a much better seizure load than alloys 18 and 19, which is due to the addition of additives that improve conformability, namely Pb,
It is recognized that this is an effect of Bi and In.

さらに第３図は本発明に係る合金２，９と従来の合金１
９について、荷重を増加させた場合の摩擦トルクの変化
の状態を測定した結果を示すグラフである。Furthermore, FIG. 3 shows alloys 2 and 9 according to the present invention and conventional alloy 1.
9 is a graph showing the results of measuring changes in friction torque when the load is increased for No. 9.

この実験は、上記焼付試験の際、荷重を増加させる途中
の状況をオシログラフで測定している。In this experiment, the situation during the load increase during the seizure test was measured using an oscillograph.

このグラフによれば、従来の合金１９では荷重を増加さ
せる度に摩擦トルクはピークの発生を伴って大きく変動
しつつ増加し、また合金２ではピークを伴う程大きな変
動は認められず滑らかに変動しているが、荷重増加の停
１Ｆ時に山形の摩擦トルク変動が生じている。According to this graph, in the conventional alloy 19, the friction torque increases with a large fluctuation accompanied by a peak every time the load is increased, and in the case of alloy 2, the friction torque fluctuates smoothly without a large fluctuation accompanied by a peak. However, when the load increases and stops at 1F, a chevron-shaped friction torque fluctuation occurs.

これに対し本発明の合金９では、荷重の増加に対して極
めて滑らかに追従して摩擦トルクが増加しており、有害
な摩擦トルク変動は生じていない。On the other hand, in Alloy 9 of the present invention, the friction torque increases extremely smoothly following the increase in load, and no harmful friction torque fluctuations occur.

これは本発明の合金がなじみ性に優れ、かつ焼付の生じ
にくいことを示している。This shows that the alloy of the present invention has excellent conformability and is less prone to seizure.

すなわち従来の合金１９にみられる変動の大きなピーク
波形は、摺動面の油膜が部分的に破壊され、固体接触が
生じこれが繰り返されると全体破壊（焼付）を生じるこ
とを意味しており、このような波形を生じない本発明の
合金２，９はなじみ性および耐焼付荷重が高い。In other words, the peak waveform with large fluctuations seen in conventional Alloy 19 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. Alloys 2 and 9 of the present invention, which do not produce such corrugations, have high conformability and seizure load resistance.

なお、本発明に係る合金組成において、Ａ１中には通常
の精練技術ではどうしても避けられない不純物が含まれ
ることは勿論である。In addition, in the alloy composition according to the present invention, it goes without saying that A1 contains impurities that cannot be avoided by ordinary scouring techniques.

次に第４図は本発明に係る合金１，５，１４と従来の合
金１８，１９について摩耗試験を行なったときの荷重を
増加させた場合の摩耗量の変化の状態を測定した結果を
示すグラフである。Next, Figure 4 shows the results of measuring changes in the amount of wear when the load was increased when a wear test was conducted on alloys 1, 5, and 14 according to the present invention and conventional alloys 18 and 19. It is a graph.

このグラフによれば、従来の合金１８と比較しＣｒを添
加した１，５，１４また従来の合金中Ｓｉを添加した１
９は摩耗量が極めて少ないことが認められる。According to this graph, compared with the conventional alloy 18, 1, 5, 14 with added Cr and 1 with Si added in the conventional alloy
No. 9 is recognized to have extremely low wear amount.

またＣｒを添加した合金でもＣｒ含有量の差によって摩
耗量に差が認められる。Furthermore, even in alloys to which Cr is added, differences in the amount of wear are observed depending on the difference in Cr content.

すなわち、Ｃｒ添加量の多い５，１４の方が１より摩耗
量が少ない。That is, Nos. 5 and 14, which have a large amount of Cr added, have a smaller amount of wear than No. 1.

この実験は、軸回転数１０００ｒ．ｐ．ｍ，軸材として
Ｓ５５Ｃ焼入れ材（軸アラサ１μ）を使用し、一定油温
（１２０℃）の強制潤滑下において荷重を増加させた場
合の、各荷重での摩耗量を測定したものであり、本発明
の合金１，５，１４は合金１８に比しはるかに優れた耐
摩耗性を示しており、これはＣｒ添加による効果である
ことが認められる。In this experiment, the shaft rotation speed was 1000 r. p. m, S55C hardened material (shaft roughness 1μ) was used as the shaft material, and the amount of wear was measured at each load when the load was increased under forced lubrication at a constant oil temperature (120°C). Alloys 1, 5, and 14 of the present invention exhibit much better wear resistance than Alloy 18, and this is recognized to be the effect of the addition of Cr.

次に第５図は第４図と同様の実験を軸材質として球状黒
鉛鋳鉄材を使用して行なったものである。Next, FIG. 5 shows an experiment similar to that of FIG. 4 conducted using spheroidal graphite cast iron as the shaft material.

第４図の鋼軸の場合と比して、本発明に係る合金１，５
，１６は、従来の合金である１８と摩耗量において大き
な差が認められ、Ｃｒ添加による耐摩耗性向上効果は、
球状黒鉛鋳鉄軸を使用した場合の方が鋼軸を使用した場
合より、より明確となる。Compared to the case of the steel shaft in FIG. 4, alloys 1 and 5 according to the invention
, 16 was found to have a large difference in wear amount from the conventional alloy 18, and the effect of improving wear resistance due to the addition of Cr was
This is more obvious when using a spheroidal graphite cast iron shaft than when using a steel shaft.

なお、第４図、第５図の結果では、本件発明品と従来材
の一部とは同様の結果を示しているが、従来材は第１〜
３図で明らかなように欠点を持ち、結局は充分な合金と
はいえない。In addition, in the results shown in FIGS. 4 and 5, the present invention product and a part of the conventional material show similar results, but the conventional material shows
As is clear from Figure 3, it has drawbacks, and in the end it cannot be said to be a sufficient alloy.

次に第６図は本発明に係る合金１．２，９と従来の合金
１８，１９，２０について焼付試験を相手材質として球
状黒鉛鋳鉄軸を使用して行なったときの、焼付に至った
ときの面圧を示すグラフである。Next, Figure 6 shows the results of a seizure test for alloys 1.2, 9 according to the present invention and conventional alloys 18, 19, and 20 using a spheroidal graphite cast iron shaft as the mating material. It is a graph showing surface pressure of.

このグラフによれば従来の合金１８と比較しＣｒを添加
した合金１，２，９は焼せ面圧が高いことが認められる
。According to this graph, it is recognized that Alloys 1, 2, and 9 to which Cr is added have higher sintering surface pressures than the conventional Alloy 18.

またＣｒを添加した合金宅もＣｒ含有量の差によって焼
付荷重に差が認められる。Also, in the case of alloys containing Cr, differences in seizure load are observed depending on the difference in Cr content.

すなわちＣｒ添加量の多い合金２の方が１より耐焼付性
に優れている。In other words, Alloy 2 with a large amount of Cr added has better seizure resistance than Alloy 1.

中でもｐｂを添加した合金９については、すぐれた耐焼
付性を示している。Among them, Alloy 9 containing PB shows excellent seizure resistance.

また従来の合金１９は、その化学成分中のＳｉによると
思われる耐焼付性の向下が見られ、かつｐｂが添加され
た合金２０はよりすぐれた本件発明と同様の効果が認め
られる。In addition, the conventional alloy 19 shows an improvement in seizure resistance, which is thought to be due to Si in its chemical composition, and the alloy 20 to which PB is added exhibits the same superior effect as the present invention.

ただし前述した如く、これら従来材は本発明の合金の特
徴の一つである高温硬さの低下防止、耐疲労性の向上等
は認められない。However, as mentioned above, these conventional materials do not exhibit one of the characteristics of the alloy of the present invention, such as prevention of reduction in high-temperature hardness and improvement in fatigue resistance.

以上の通り本発明に係るアルミニウム軸受合金は、Ｃｒ
添加による硬さの向上、高温硬さの低下防止、Ｓｎ粒子
の粗大化阻止効果、これらを通じての耐疲労性向上、お
よび耐摩耗性の向上に加え、特に球状黒鉛鋳鉄軸に使用
する場合においての耐摩耗性、耐焼付性の向上、またＣ
ｒとともに添加して効果のあるＰｂ，Ｂｉ、Ｉｎにより
なじみ性の向上、耐焼付性の向上を図ることができ、さ
らにＣｕ、Ｍｇを加えれば高蝉強度がより向上する。As described above, the aluminum bearing alloy according to the present invention has Cr
In addition to improving hardness, preventing a decrease in high-temperature hardness, and inhibiting the coarsening of Sn particles through addition, it improves fatigue resistance and wear resistance, especially when used in spheroidal graphite cast iron shafts. Improved wear resistance, seizure resistance, and C
Pb, Bi, and In, which are effective when added together with r, can improve conformability and seizure resistance, and further addition of Cu and Mg can further improve high strength.

また裏金鋼板との圧接後の圧延焼鈍を高温度長時間で行
なえるので、両者の密着性を高めることができる。Further, since rolling annealing after pressure bonding with the backing steel plate can be performed at high temperature for a long time, the adhesion between the two can be improved.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、本発明に係るアルミニウム軸受合金と従来の
同種軸受合金等との温度変化に伴う硬度変化の様子をプ
ロットしたグラフ、第２図は、同じく耐疲労面圧の変化
の様子をプロットしたグラフ、第３図は同じく荷重を増
加させた場合の摩擦トルクの変化の状態を示すグラフ、
第４図は、鋼軸に対して同じく荷重を増加させた場合の
摩耗量の変化の状態を示すグラフであり、第５図は同じ
く球状黒鉛鋳鉄軸に対しての摩耗量を示すグラフである
。 第６図は球状黒鉛鋳鉄軸に対しての焼付面圧を示すグラ
フである。Fig. 1 is a graph plotting changes in hardness due to temperature changes between the aluminum bearing alloy according to the present invention and conventional similar bearing alloys, etc., and Fig. 2 is a graph plotting changes in fatigue resistance surface pressure. Figure 3 is a graph showing the change in friction torque when the load is increased.
Figure 4 is a graph showing how the amount of wear changes when the load is similarly increased on a steel shaft, and Figure 5 is a graph showing the amount of wear on a spheroidal graphite cast iron shaft. . FIG. 6 is a graph showing the seizure pressure against the spheroidal graphite cast iron shaft.

Claims (1)

【特許請求の範囲】 １ 重量でスズ３．５〜３５％、クロム１．０を越え７
．０％、および残部が本質的にアルミニウムからなるア
ルミニウムースズ系軸受合金。 ２ 重量でスズ３．５〜３５％、クロム１．０を越え７
．０％、銅および（または）マグネシウム３，０％以下
（０を含まず）、および残部が本質的にアルミニウムか
らなるアルミニウムースズ系軸受合金。 ３ 重量でスズ３．５〜３５％、クロム１．０を越え７
．０％、銅および（または）マグネシウム３．０％以下
（０を含まず）、Ｐｂ、Ｂｉ、Ｉｎの少なくとも１種を
９．０％以下（０を含まず）、および残部が本質的にア
ルミニウムからなるアルミニウム−スズ系軸受合金。 ４ 重量でスズ３．５〜３５％、クロム１．０を越え７
．０％、Ｐｂ、Ｂｉ、Ｉｎの少なくとも１種を９．０％
以下（０を含まず）、および残部が本質的にアルミニウ
ムからなるアルミニウム−スズ系軸受合金。[Claims] 1 3.5 to 35% tin by weight, more than 1.0 chromium 7
．． An aluminum-tin based bearing alloy consisting of 0% and the balance essentially aluminum. 2 3.5 to 35% tin by weight, over 1.0 chromium 7
．． 0%, copper and/or magnesium 3.0% or less (excluding 0), and the balance essentially aluminum. 3 3.5 to 35% tin by weight, more than 1.0 chromium 7
．． 0%, 3.0% or less (excluding 0) of copper and/or magnesium, 9.0% or less (excluding 0) of at least one of Pb, Bi, In, and the remainder essentially aluminum An aluminum-tin bearing alloy consisting of 4 3.5 to 35% tin by weight, over 1.0 chromium 7
．． 0%, at least one of Pb, Bi, In 9.0%
An aluminum-tin bearing alloy in which the following (excluding 0) and the balance essentially consist of aluminum.