JP2004028276A - Main motion mechanism of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the abrasion of both of a crankshaft and a sliding bearing in a rotation mechanism of an internal combustion engine formed by including a micro alloying steel crankshaft treated by neither high frequency hardening nor surface hardening and having a structure comprising perlite and pro-eutectoid ferrite, or the perlite, and the sliding bearing installed in the outer circumference of the crankshaft and composed of an aluminum bearing alloy. <P>SOLUTION: The area fraction of pro-eutectoid perlite is 3% or less and the surface roughness of the crankshaft of the surface sliding with the sliding bearing is Rz 5μm or less. Hard substances composed of Si or including Si and having the hardness of Hv 900 or more are distributed in the matrix for the aluminum bearing alloy and the Si content is 1-4 mass%. <P>COPYRIGHT: (C)2004,JPO

Description

【００４２】
実施例１〜６では鋼軸およびＡｌ系合金の両方の摩耗量が少なくなっている。これに対して比較例７は初析フェライトの面積率が多いためにＡｌ系合金の摩耗が多い。さらに、比較例８は表面粗さが粗いために軸受の摩耗が多い。比較例９はＡｌ系合金のＳｉ量が低いために軸受摩耗量が多い。比較例１０はＡｌ系の合金のＳｉ量が多いために軸摩耗量がい多い。比較例１１は初析フェライト面積率が多く、表面積粗さも粗く，かつＳｉ含有量が低いために軸受摩耗量が多い。比較例１２は初析フェライト面積率が多く。表面粗さも粗く、かつＳｉ含有量も多いために軸と軸受摩耗量の両方が多い。
【００４３】
実施例２
実施例１のＡｌ系合金のＳｉに代えてＳｉ_３Ｎ_４を使用し、表１の２同じ条件で試験したところ鋼軸の摩耗量が１μｍＡｌ系合金の摩耗量が１μｍであった。
【００４４】
実施例３
実施例１の鋼材に代えて、Ｃ：０．６２％、Ｓｉ：０．２５％、Ｍｎ：０．８７％、Ｓ：０．０６％、Ｃｒ：０．１９％、Ａｌ：０．００３％、Ｏ：０．００２％、Ｐｂ：０．１９％、残部Ｆｅ及び不可避不純物（Ｐ，Ｃｕ，Ｎｉ，Ｍｏ，Ｎ）からなる鋼を使用し、表１の２と同じ条件で試験したところ鋼軸の摩耗量が１μｍ、Ａｌ系合金の摩耗量が１μｍであった。
【００４５】
【発明の効果】
以上説明したように、本発明は非調質クランク鋼軸とＡｌ系合金すべり軸受の組成、組織、表面粗さを総合的に考察して、低コストの方法で両者の摩耗を少なくすることに成功した。
【図面の簡単な説明】
【図１】内燃機関の主運動機構の要部を示す図面である。
【符号の説明】
１０　摺動部
１１　（クランク）ジャーナル部
１２　（クランク）ピン部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a main motion mechanism of an internal combustion engine, and more specifically, to a main motion mechanism including a crankshaft and a slide bearing mounted on an outer periphery of the crankshaft.
[0002]
As shown in FIG. 1, a crankshaft of an internal combustion engine of an automobile or the like includes a crankpin portion 12 which is a connection portion of a connecting rod connected to a piston (not shown), and a crank journal which is a mounting portion to a cylinder block. A part 11. The rotational movement of the crankshaft is supported by the half-part sliding bearing made of an Al-Sn-based aluminum alloy or a Cu-Pb-based copper alloy at the connection portion and the attachment portion. Further, an oil film is formed on the sliding portion 10 between the pin and the journal of the crankshaft and the slide bearing.
[0003]
Crankshaft materials are broadly divided into cast iron and steel.
As the steel material, a material obtained by quenching and tempering medium carbon steel for machine structure such as S50C or alloy steel such as SCM440 has been used. Thereafter, V-added steel has come to be used as a non-heat treated steel from which quenching and tempering has been omitted. A non-heat treated steel to which Ti is added as an additional element in place of V is known, for example, from Japanese Patent No. 3149741, and its structure is a ferrite-pearlite mixed structure.
Some non-heat treated type steel materials further omit surface hardening treatment such as induction hardening and soft nitriding. The present invention belongs to this "non-heat treated steel material not subjected to induction hardening or surface hardening treatment".
It is also known that, in a non-heat treated steel having a ferrite / pearlite structure, the area ratio of proeutectoid ferrite decreases with an increase in carbon content (Japanese Patent Laid-Open No. 61-264162, FIG. 2).
[0004]
As the Al-based bearing alloy, a bimetallic alloy in which an Al-Sn-based rolled alloy is pressed against a back metal steel plate is generally used. As the Al-based bearing alloy, JIS-AJ2 (6.0 to 9.0% Sn, 0.5 to 1.0% Cu, 1.0% or less Ni, 0.5% or less Mg, balance Al), SAE 785 (0.2% Sn, 0.7-1.3% Cu, 4.5-5.5% Zn, 0.3% Fe, 0.2% Ni, 0 0.1% Mn, 1.0-2.0% Si, 0.1% Ti).
[0005]
One of the applicants, German Patent DE 32 49 133 C2 (hereinafter referred to as "German Patent"), discloses that in the final rolling before the aluminum alloy rolled sheet containing 0.5-11% Si is pressed against the back metal, A method is disclosed in which Si is coarsened and spheroidized by heating at a temperature in the range of ℃ 550 ° C. for at least 30 minutes and then cooling at a rate of less than 200 ° C./h. There are 5 or more Si particles having a size of 5 to 40 μm per 3.56 × 10 ⁻² mm ² . There are many finer Si particles than this. The coarse Si particles contribute to the improvement of bearing performance by smoothing the roughness of the spheroidal graphite (nodular) cast iron shaft.
The mating shaft in the German patent fatigue strength test is AISI 1055. This is a non-alloyed medium-carbon tempered steel used after quenching and tempering.
[0006]
According to Japanese Patent Publication No. 5-69895, the composition contains 3 to 5% Si, 8 to 20% Sn, 0.5 to 2% Cu, does not contain Cr, Mn and Pb, and the balance is Al. An Al alloy has been proposed, in which (a) Sn is formed in a net-like structure, (b) Si particles have a diameter of 20 μm or less, and 60% or more is contained in the Sn phase. The "network" means that the Al phase and the Sn phase are both continuous, and the Sn phase is continuous along the Al crystal grain boundary or the grain boundary triple point. The method of refining the Sn phase is a method of recrystallizing Al crystals and developing a network structure during annealing after cold working. In this alloy, Cr and Mn are not included because they hinder the formation of a network Sn phase. Such a composition and structure contribute to obtaining excellent seizure resistance and fatigue resistance using the nodular cast iron shaft and the steel shaft as mating shafts. Note that the steel shaft is not specified as a non-heat treated type.
[0007]
[Problems to be solved by the invention]
The steel shaft tested in the aforementioned Japanese Patent Publication No. 5-69895 is not specified as a non-heat treated steel. The steel shaft tested in the German patent is AISI 1055 tempered. Therefore, the prior art does not consider what Al-based bearing alloy is suitable for a non-heat treated steel shaft having a ferrite-pearlite structure and not subjected to surface treatment such as induction hardening.
[0008]
[Means for Solving the Problems]
The sliding state between the crankshaft and the Al-based plain bearing alloy varies depending on the combination of materials as follows.
(A) According to the aforementioned Japanese Patent Publication No. 5-69895, it is considered that the lower the hardness, the better the seizure resistance, and the better the fatigue resistance, the higher the hardness. Since the Sn particles are held in the soft Sn phase in the "structure in which Sn is in a network and wraps around Si", when pressure is applied to the Si particles, the Sn phase below the Si particles will also be deformed. It is considered that the apparent hardness of the Si particles is lower than the original hardness, so that good seizure resistance and fatigue resistance are obtained for both the cast iron shaft and the steel shaft. It is considered that the above-mentioned consideration is applicable except for the initial stage of sliding where the sliding situation is unstable.
[0009]
(B) As shown in FIGS. 16 and 17 of the German patent, Sn particles are isolated, and coarse spherical Si particles and the Sn phase are separated from each other. An Al alloy plain bearing slides on a spherical graphite shaft. Then, the Si particles sharpen the sharp edges formed by the graphite falling off the cast iron surface, thereby preventing the aluminum alloy from being worn.
[0010]
(C) When an Al-based bearing alloy such as JIS-AJ2 or SAE 785 is slid with respect to an induction hardened steel shaft, a conforming phenomenon occurs and a conformable surface is easily formed.
[0011]
(D) When an Al-based bearing alloy such as JIS-AJ2 or SAE 785 is slid against a non-heat-treated steel shaft having a ferrite-pearlite structure, a break-in phenomenon occurs in a relatively early stage, and the shaft is The Al phase and the Sn phase of the Al alloy plain bearing adhere to the ferrite phase prior to adhesion wear. Comparing (c) and (d), the induction hardened structure of the steel shaft is very hard, so that a conformable surface is easily formed in order to abrasively wear the Al alloy, but the ferrite-pearlite structure causes Al and Sn adhesion. Easy to say.
[0012]
(E) The cause of adhesive wear as described in (d) above is considered as follows. The pearlite has a sandwich structure of lamellar cementite (hardness of about Hv700) and ferrite (hardness Hv150 to 300) with submicron dimensions. When the polished steel shaft is viewed in cross section, lamellar cementite protrudes and has a fine uneven structure in which ferrite is depressed. On the other hand, proeutectoid ferrite has a continuous network or discontinuous network in plan view, and its width is much larger than the lamellar ferrite in pearlite. Proeutectoid ferrite is so-called pure iron and has a large adhesive property. Therefore, cohesive wear occurs on a non-heat treated steel shaft containing a large amount of proeutectoid ferrite.
[0013]
The present invention has a structure composed of pearlite and proeutectoid ferrite or pearlite, in order to solve the above problems, a crankshaft made of a non-heat treated steel material not subjected to induction hardening or surface hardening treatment, and the crankshaft of this crankshaft In a main motion mechanism of an internal combustion engine comprising: a sliding bearing comprising an Al-based alloy mounted on an outer periphery; wherein the non-heat-treated steel has an area fraction of proeutectoid ferrite of 3% or less; The surface roughness of the crankshaft on the surface that slides with the sliding bearing is Rz 0.5 μm or less, and the Al-based alloy is made of Si or contains Si, and a hard material having a hardness of Hv 900 or more is formed of an Al matrix. And a main kinetic mechanism of the internal combustion engine, characterized in that the Si content is 1 to 4% by mass or less and the balance is substantially Al.
Hereinafter, the present invention will be described in detail.
[0014]
On the premise of the above-mentioned wear mechanisms (c), (d) and (e), in the present invention, a crankshaft made of a non-heat-treated steel material not subjected to induction hardening or surface hardening treatment (hereinafter referred to as "non-heat-treated crank steel shaft") ), The promotion of initial wear is suppressed. That is, since initial adhesion wear is unlikely to occur between the pearlite structure and the Al alloy or Al-Sn alloy, it is necessary to suppress the upper limit of the area fraction of proeutectoid ferrite. Preferably, the area fraction of proeutectoid ferrite is 0.1 to 1%.
[0015]
Further, the roughness of the surface where the non-heat treated crank steel shaft contacts the plain bearing is set to Rz 0.5 μm or less. That is, by setting the roughness to Rz 0.5 μm or less, the formation of the fluid lubricated surface is facilitated so that even if the adhesion occurs, the seizure of the bearing does not occur. The preferred roughness is Rz 0.4 μm or less.
[0016]
Further, it is assumed that a hard material having an Hv of 900 or more is dispersed in the Al matrix of the Al alloy of the sliding bearing, and the Si content of the Al alloy is 1 to 4% by mass.
In the present invention, the “Al matrix” is a region where an Al peak is observed in EPMA analysis. In addition, the fact that the hard substance is dispersed in the Al matrix has a substantial meaning, and a coincidence region where the peak of Al and the peak of the hard substance that are observed by using the image analysis and the EPMA together are detected at the same time. The amount may be 80% or more, more preferably 90% or more, based on the total number of hard particles. The remaining small amount of the hard material may be dispersed in the Sn or Pb phase or the like.
[0017]
In the present invention, the hardness of a hard object is the hardness of the substance having a measurable size. That is, since the hard particles dispersed in the Al-based alloy may be smaller than the measurable size, the hard particles are set to the original values as described above. When the hardness of such hard particles is Hv900 or more, even if Al or Sn adheres to the mating shaft, it prevents the hard particles from shaving off the adhered matter and causing seizure.
The upper limit of the hardness of the hard material is preferably Hv3500. As the hard material, Si particles of about Hv1200 can be used, and other ceramic particles having good compatibility with Al, such as Si ₃ N ₄ and Al ₂ O _3, can also be used. The size of the ceramic particles is preferably 6 μm or less. When the hard material is Si, the content is preferably 1 to 4% by mass, and the amount of the hard material other than Si is preferably 0.5 to 4% by mass.
[0018]
Further, in the present invention, the Si content of the Al-based alloy is 1 to 4% by mass. When the Si content is 1% by mass, the effect of the above-mentioned hard material is not exhibited. On the other hand, when the Si content exceeds 4% by mass, the tendency of the hard material to scrape off the ferrite of the mating shaft becomes remarkable, which is not preferable. The preferred Si content is 2 to 4% by mass.
[0019]
An Al-based alloy having the above-mentioned structural characteristics and a method of manufacturing a plain bearing in which the Al-based alloy is integrated with a backing metal are described in German Patent No. 9, page 57, line 66, Table 2 and Table 2 (continued). ), And the invention method of coarsening and spheroidizing Si. The conventional method is a usual method for producing a bimetallic plain bearing, and the invention method is a method for slowing down cooling after final rolling described in paragraph 0005. Note that these production conditions are essentially different from the conditions for refining the Sn phase disclosed in Japanese Patent Publication No. 5-69895.
When ceramic particles are used as a hard material, they are added to a molten aluminum alloy and then treated by a process described in a German patent.
[0020]
In the Al-based alloy of the present invention, the balance of the above components is substantially Al. The Al-based alloy of the present invention further comprises, for example, 1 to 5% Pb, 0.5 to 2% Cu, 0.1 to 1% Cr, 0.5% in addition to 2 to 20% of Sn. It may contain one or more such as ， 2% Mg, 0.1-1% Zr, Mn, V, Ti, and / or B (percentages are by weight). As in this composition example, the total amount of components other than Si may be 40%, that is, the Al content may be at least 60%.
Of the above components, Sn greatly contributes to the improvement of the bearing performance when the above-mentioned means for preventing initial adhesion is taken. Pb is also easy to adhere at the initial stage, but if anti-adhesion measures are similarly taken, it contributes to improvement in bearing performance. However, when the content of Sn and Pb increases, the ratio of Si particles taken into the Sn and Pb phases increases, which is not preferable. Cr refines Sn, but since refined Sn also has an initial adhesion tendency, it has essentially no effect on preventing adhesion to a non-heat treated steel shaft. However, since the fine Sn phase is preferable in terms of fatigue strength and the like, Cr can be added. Although Cu and Mg bring about solid solution strengthening and / or precipitation strengthening of the Al-based alloy, the hardness of the precipitate is less than Hv900 and thus does not correspond to a hard material. That is, the precipitates of Cu and Mg do not have the effect of preventing initial adhesion, but can strengthen the Al-based alloy.
[0021]
Next, a description will be given of a steel material for a crankshaft in which a countermeasure against wear of a crankshaft and / or a sliding bearing during long-term use is taken in addition to the initial adhesion wear described above.
This steel material for a crankshaft is, by mass%, C: 0.62 to 0.80%, Si: 0.60% or less (excluding 0), Mn: 0.30 to 1.80%, S: 0. 0.04 to 0.35%, Cr: 0.05 to 0.50%, Al: less than 0.005% (excluding 0), O: 0.0020% or less (excluding 0), balance Fe and It is made of unavoidable impurities and contains sulfide-based inclusions having a thickness of 20 μm or less.
[0022]
Since the amount of Al in the steel material for a crankshaft is regulated to less than 0.005%, the generation of hard inclusions is suppressed, and damage to the slide bearing can be prevented. Further, S is contained in the steel for crankshafts in an amount of 0.04 to 0.35%, and the amount of Al is regulated to less than 0.005% and the amount of O (oxygen) is regulated to 0.0020% or less. Can be improved in machinability. Furthermore, sulfide-based inclusions such as MnS generated by the inclusion of S deteriorate the wear resistance of the crankshaft when the thickness is large, but since the thickness is 20 μm or less, the wear resistance of the crankshaft is reduced. Can be good.
The reasons for limiting the amounts (% by mass) of each element of the steel material for a crankshaft are described below.
[0023]
C: 0.62 to 0.80%,
C is an element necessary for securing strength and improving wear resistance. If C is less than 0.62%, the strength and wear resistance of the steel decrease, so the lower limit needs to be 0.62%, preferably 0.67% or more. On the other hand, when C exceeds 0.80%, the strength is increased more than necessary, and the machinability of steel decreases, so the upper limit needs to be 0.80%, preferably 0.76% or less. is there.
[0024]
Si: 0.60% or less,
Si is an element that is effective as a deoxidizing aid during steelmaking and is also an element that is effective in improving strength and wear resistance. However, if Si exceeds 0.60%, the machinability of the steel is reduced, so the upper limit must be 0.60%, preferably 0.35% or less.
[0025]
Mn: 0.30 to 1.80%,
Mn is an element that is effective as a deoxidizing aid at the time of steel making and is an element necessary for ensuring the strength of steel. If Mn is less than 0.30%, the strength is reduced, so the lower limit must be 0.30%, preferably 0.40% or more. On the other hand, when Mn exceeds 1.80%, a low-temperature transformation structure such as bainite or martensite is generated, which causes a decrease in the machinability of steel. Therefore, the upper limit is 1.80%, preferably 1.50%. It is necessary to:
[0026]
S: 0.04-0.35%,
S is an element indispensable for improving the machinability of steel. If S is less than 0.04%, the effect cannot be obtained, so the lower limit needs to be 0.04%, preferably 0.13% or more. On the other hand, if S exceeds 0.35%, the strength and hot workability of steel are impaired, so the upper limit must be 0.35%, preferably 0.20% or less.
[0027]
Cr: 0.05 to 0.50%,
Cr is an element effective for improving the wear resistance of steel. If Cr is less than 0.05%, the improvement cannot be expected, so the lower limit needs to be 0.05%, preferably 0.10% or more. On the other hand, if Cr exceeds 0.50%, the machinability of the steel is reduced, so the upper limit must be 0.50%, preferably 0.35% or less.
[0028]
Al: less than 0.005%,
Since Al generates Al ₂ O ₃ and AlN which are harmful to the wear resistance of the slide bearing and the machinability of steel, it is necessary to keep Al as low as possible. If Al is 0.005% or more, the increase and coarsening of Al ₂ O ₃ and AlN are caused, and the wear resistance of the slide bearing and the machinability of steel are deteriorated. %.
[0029]
O (oxygen): 0.0020% or less,
If O exceeds 0.0020%, there is a problem that the thickness of the sulfide-based inclusions increases and the wear resistance of the steel decreases, so the upper limit must be made 0.0020%.
[0030]
The sulfide inclusions are formed in the crankshaft steel. It is necessary to regulate the thickness of the sulfide-based inclusion to 20 μm or less from the viewpoint of the wear resistance of steel. If the thickness of the sulfide-based inclusions exceeds 20 μm, the wear resistance will decrease.
[0031]
More preferable steel materials for crankshafts are, by mass%, C: 0.62 to 0.80%, Si: 0.60% or less, Mn: 0.30 to 1.80%, and S: 0.04 to 0. 35%, Cr: 0.05 to 0.50%, V: 0.01 to 0.09%, Al: less than 0.005%, O: 0.0020% or less, balance Fe and inevitable impurities, and It contains sulfide inclusions having a thickness of 20 μm or less.
This steel for crankshafts contains V in an amount of 0.01 to 0.09% by mass in addition to the above components. V is an element effective for securing the wear resistance of steel. In order to obtain the effect, the content must be at least 0.01%, so the lower limit must be 0.01%, preferably 0.03% or more. However, if the V content exceeds 0.09%, the cost increases, so the upper limit is set to 0.09%.
[0032]
More preferable crankshaft steels further include, by mass%, Bi: 0.01 to 0.30%, Pb: 0.01 to 0.30%, Ca: 0.0003 to 0.020%, and Mg: 0. When one or more selected from the group of 0003 to 0.0020% and REM: 0.001 to 0.10% is contained, the machinability of steel is further improved. Next, the reasons for limiting the content of each component will be described.
[0033]
Bi: 0.01 to 0.30%,
Bi is an element effective for improving the machinability of steel. In order to exert its effect, Bi needs to be contained at 0.01% or more, preferably 0.02% or more. On the other hand, when Bi is contained in excess of 0.30%, the effect is saturated, the cost is increased, and the hot workability is impaired. Therefore, the upper limit is 0.30%, preferably 0.15%. It is necessary to:
[0034]
Pb: 0.01 to 0.30%,
Pb is an element that is effective for improving machinability and exhibits the same effect as Bi, and it is necessary to contain 0.01% or more, preferably 0.04% or more in order to exhibit the effect. On the other hand, when Pb is contained in excess of 0.30%, the effect is saturated and the hot workability is impaired. Therefore, it is necessary to set the upper limit to 0.30%, preferably 0.25% or less. is there.
[0035]
Ca: 0.0003-0.020%,
Ca is an element that is effective in improving machinability, and in order to exhibit its effect, its content must be 0.0003% or more, preferably 0.0005% or more. On the other hand, if the content exceeds 0.020%, the effect is saturated and the cost increases, so the upper limit is made 0.020%.
[0036]
Mg: 0.0003-0.020%,
Mg exhibits the same effect as Ca, and when it is present as a composite with Ca, a large machinability improving effect and an anisotropic mechanical property improving effect are obtained. In order to obtain the effect, Mg must be at least 0.0003% or more, preferably 0.0005% or more. However, even if it is contained more than necessary, the effect becomes saturated and is useless. 0.020%.
[0037]
REM: 0.001 to 0.10%
REM is a rare earth element that is effective for improving machinability, and it is necessary to contain 0.001% or more, preferably 0.005% or more in order to exhibit its effect. On the other hand, if the content of REM exceeds 0.10%, the effect is saturated and the cost is increased. Therefore, the upper limit is set to 0.10%. Hereinafter, the present invention will be described in detail with reference to examples.
[0038]
【Example】
Example 1
As a crankshaft steel, C: 0.71%, Si: 0.23%, Mn: 0.63%, S: 0.164%, Cr: 0.20%, Al: 0.003% by weight %, O: 0.002%, Ca: 0.003%, a steel material consisting of the balance Fe and unavoidable impurities (P, Cu, Ni, Mo, N) was forged to a diameter of 60 mm, and cooled after completion of the forging. The cooling method is water cooling, forced air cooling by air blowing, cooling in still air, or a combination of these, ie, water cooling → forced air cooling, forced air cooling → still air cooling, and the amount of proeutectoid ferrite changes as shown in Table 1. I let it.
Thereafter, the outer peripheral surface of the forged shaft was polished with emery paper having a different particle size to change the surface roughness as shown in Table 1.
[0039]
The method for producing the Al-based alloy containing 12% Sn was the same as the process and conditions of the conventional method of the German patent. The surface of the alloy was finished to a roughness Rz of 1 μm.
[0040]
The method of the abrasion test was as follows.
Wear test The wear test of the shaft and the bearing was performed using a rotating load bearing wear tester.
Test conditions Shaft diameter: 42 mm, bearing width: 17 mm, shaft rotation speed: 8000 rpm, oil type: 5W-20, bearing surface pressure: 29 MPa
After operating for 3 hours under the above conditions, the wear amount of the shaft and the bearing was measured.
Table 1 shows the test results.
[0041]
[Table 1]

[0042]
In Examples 1 to 6, the amounts of wear of both the steel shaft and the Al-based alloy are reduced. On the other hand, in Comparative Example 7, since the area ratio of the proeutectoid ferrite is large, the Al-based alloy has much wear. Further, in Comparative Example 8, the bearing had a large amount of wear because the surface roughness was rough. Comparative Example 9 has a large amount of bearing wear because the amount of Si in the Al-based alloy is low. Comparative Example 10 has a large amount of shaft wear because the Al-based alloy has a large amount of Si. Comparative Example 11 had a large pro-eutectoid ferrite area ratio, a large surface area roughness, and a low Si content, so that the bearing wear was large. Comparative Example 12 has a large proeutectoid ferrite area ratio. Since the surface roughness is large and the Si content is large, both the shaft and bearing wear are large.
[0043]
Example 2
When the test was conducted under the same conditions as in Table 2 using Si ₃ N ₄ instead of Si of the Al-based alloy of Example 1, the wear amount of the steel shaft was 1 μm, and the wear amount of the Al-based alloy was 1 μm.
[0044]
Example 3
Instead of the steel material of Example 1, C: 0.62%, Si: 0.25%, Mn: 0.87%, S: 0.06%, Cr: 0.19%, Al: 0.003% , O: 0.002%, Pb: 0.19%, and the balance of Fe and inevitable impurities (P, Cu, Ni, Mo, N) was used. The wear amount of the shaft was 1 μm, and the wear amount of the Al-based alloy was 1 μm.
[0045]
【The invention's effect】
As described above, the present invention comprehensively considers the composition, structure, and surface roughness of a non-heat-treated crank steel shaft and an Al-based alloy plain bearing, and reduces wear of both parts by a low-cost method. Successful.
[Brief description of the drawings]
FIG. 1 is a drawing showing a main part of a main motion mechanism of an internal combustion engine.
[Explanation of symbols]
10 Sliding part 11 (Crank) Journal part 12 (Crank) Pin part

Claims (5)

A non-heat treated steel crankshaft having a structure consisting of pearlite and proeutectoid ferrite or pearlite, and not subjected to induction hardening or surface hardening, and a slip comprising an Al-based alloy mounted on the outer periphery of the crankshaft In the main motion mechanism of the internal combustion engine including the bearing, the non-heat treated steel has an area fraction of pro-eutectoid ferrite of 3% or less, and a surface of the crankshaft which slides with the sliding bearing. The Al-based alloy has a roughness of Rz 0.5 μm or less, and the Al-based alloy is made of or contains Si, and a hard material having a hardness of Hv900 or more is dispersed in an Al matrix, and the Si content is 1 to 4 A main kinetic mechanism for an internal combustion engine, characterized in that the mass is% by mass and the balance is substantially Al. The Al-based alloy is, in mass%, 2 to 20% Sn, 1 to 5% Pb, 0.5 to 2% Cu, 0.1 to 1% Cr, 0.5 to 2%. 2. The internal combustion engine according to claim 1, wherein the internal combustion engine contains one or more members selected from the group consisting of Mg,, and 0.1 to 1% of Zr, Mn, Ti, and / or B. 3. Main motion mechanism. The non-tempered steel material is, by mass%, C: 0.62 to 0.80%, Si: 0.60% or less (excluding 0), Mn: 0.30 to 1.80%, S: 0.04 to 0.35%, Cr: 0.05 to 0.50%, Al: less than 0.005% (excluding 0), O: 0.0020% or less (excluding 0), balance Fe The main motion mechanism of an internal combustion engine according to claim 1 or 2, wherein the main motion mechanism comprises a sulfide-based inclusion having a thickness of 20 µm or less. The non-heat treated steel material further contains, by mass%, Bi: 0.01 to 0.30%, Pb: 0.01 to 0.30%, Ca: 0.0003 to 0.020%, and Mg: 0 4. The main motion mechanism of the internal combustion engine according to claim 3, wherein the main motion mechanism contains one or more selected from the group consisting of 0.0003 to 0.0020% and REM: 0.001 to 0.10%. . The main motion mechanism of an internal combustion engine according to claim 3 or 4, wherein the non-heat treated steel further contains V: 0.01 to 0.09 mass%.

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