JP2014196813A - Sliding bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sliding bearing which prevents deterioration of bearing characteristics due to exfoliation of an overlay from aluminum alloy in an aluminum alloy sliding bearing with solid lubricant overlay.SOLUTION: A sliding bearing is provided by applying a resin overlay onto the surface of an aluminum alloy rolled plate which contains 1 to 20% of Sn, 0.5 to 12% of Si and >0.20% and ≤2.0% of Fe and consists of the remainder of Al and inevitable impurities. Therein, the resin overlay has a composition of (1) solid lubricant-MoS, PTFE, graphite, WS, h-BN and SbOand (2) binder-polyamide imide[PAI] resin, polyimide resin, phenol resin, polyacetal resin, polyether ether ketone resin, polyphenylene sulfide resin and/or epoxy resin.

Description

The present invention relates to a slide bearing. More specifically, the present invention relates to a slide bearing in which a resin overlay is baked on the surface of an aluminum alloy layer for a slide bearing instead of a metal overlay such as Pb and Sn.

Sliding bearing alloys are roughly classified into copper alloys and aluminum alloys. Aluminum alloys have excellent wear resistance, and copper alloys have excellent compatibility. An aluminum alloy for a slide bearing that further improves the wear resistance of the aluminum alloy and does not use an overlay has been proposed by the present applicant in Japanese Patent Publication No. 62-42983. In patent document 1, before press-contacting an Al-Sn type bearing alloy rolled sheet to a back metal plate, it anneals at 350-550 degreeC, and coarsens and agglomerates Fe, Si, etc. which were added to this alloy. Propose that. The composition, structure and structure of the aluminum alloy are as follows. Composition-(a) 1-35 wt% (hereinafter the same) Sn, (b) 0.5-11% Mn, Fe, Mo, Ni, Zr, Co, Ti, Sb, Cr and / or Nb, ( c) 0.1-10% Pb, Cd, In, Tl and / or Bi, (d) 0.1-2% Cu and / or Mg. Tissue-Bulk particles composed of the element (b) or containing the element (b) are formed, and there are 5 or more particles having a major axis size of 5 to 40 μm per 3.56 × 10 ⁻² mm ² . Also, the bearing structure-overlay is not used, and the lump particles on the surface of the sliding bearing ensure the familiarity with the mating shaft.

On the other hand, the present applicant has proposed an overlay for an aluminium-based bearing alloy comprising 90 to 55% by weight of a solid lubricant and the remaining polyimide-based binder in Patent Document 2: Japanese Patent Laid-Open No. 4-83914. The aluminum-based bearing alloy contains 10% or less of Cr, Si, Mn, Sb, Sr, Fe, Ni, Mo, Ti, W, Zr, V, Cu, Mg, and / or Zn (hereinafter referred to as “strengthening component”). In the examples, Al-12Sn-1.8Pb-1.0Cu-3.0Si is described as containing 20% or less of Sn, Pb, In, Tl and / or Bi. -0.3Cr has been tested. In addition, fatigue resistance and seizure resistance depending on whether or not an aluminum alloy is ground-treated are compared.
Patent Document 2 can be said to be a technique of attaching a solid lubricant overlay having a conformability to an aluminum-based bearing alloy, but among a number of strengthening components, it is used for a normal rolling bearing rolling plate. There are quite a few elements that cannot be done. For example, heavy metals such as W and Mo are difficult to be alloyed with aluminum by as much as 10% unless special measures such as forced cooling of the molten metal are taken. Further, Fe is used in a lump form in Patent Document 1 that does not use an overlay, but is an impurity in a normal aluminum alloy.

Non-patent Document 1: Tribology Conference of the Japan Society of Tribology Tribology Conference Tokyo 1999-5 Proceedings “Development of plain bearing material with solid lubricated overlay (1st report) ) A13 ”. In Non-Patent Document 1, the surface of an aluminum alloy bearing material having a composition of Al-12.5Sn-2.7Si-1Cu-0.2Cr-2Pb is roughened to 5 μmRz, and a resin overlay having a thickness of 5 μm is baked thereon. The surface roughness of the overlay is 2 to 3 μm Rz. The resin-based overlay is composed of an epoxy resin or polyamideimide (PAI) resin and a solid lubricant, and the solid lubricant is MoS ₂ , graphite or h-BN.

Patent Document 3: Japanese Patent Application Laid-Open No. 2002-61652 discloses a slide bearing in which a resin coating layer is formed on a bearing alloy layer. The resin coating layer has a tensile strength at 25 ° C. of 70 to 110 MPa and an elongation of 7 70-30% by volume of a thermosetting resin having a tensile strength at 200 ° C. of 15 MPa or more and an elongation of 20% or more and good elongation at a high temperature and 30-70% by volume of a solid lubricant. (Here, the total of both is 100 vol%), and the Vickers hardness Hv of the resin coating layer is 20 or less. The same aluminum alloy as in Patent Document 1 is described, and the aluminum alloy used in the examples is Al-11Sn-1.8Pb-1Cu-3Si.

Patent Document 4: Japanese Patent Application Laid-Open No. 2004-263727 proposes that the glass transition point of the coating resin of the sliding bearing with a solid lubricant overlay be 150 to 250 ° C. The aluminum alloy is the same as that in Patent Document 2, and the aluminum alloy used in the examples also has the same composition as that in Patent Document 2.

Non-patent document 2 explaining technology about 15 years after Patent Document 2: Tribology Society of Japan, Tribology Conference Proceedings, Tottori 2004-11 “Tribology of Sliding Parts at Toyota: 1A3” According to the item 2), it can be seen that the aluminum alloy plain bearing with a solid lubricant overlay of Patent Document 2 is now mounted on a commercial version car.

The following summarizes and summarizes the conventional knowledge on aluminum alloy plain bearings with solid lubricant overlays.
(A) Surface treatment of aluminum alloy In Patent Document 2, the surface of the aluminum alloy is subjected to a treatment such as alkali etching, pickling and zinc phosphate conversion treatment, or a surface treatment is performed without applying a solid lubricant overlay. Although it is baked, the surface treatment is better in terms of seizure resistance and fatigue resistance. However, commercially available bearings do not employ a surface treatment because the surface treatment increases the cost, but does not provide a performance suitable for it.
(B) Conformity and wear of solid lubricant overlay The conformability of the overlay is ensured by a solid lubricant, particularly MoS ₂ . That is, when the MoS ₂ is cleaved, low friction and familiarity of the sliding surface are realized.
In the wear test example of Patent Document 2, since the underlying aluminum alloy is surface-treated, the adhesion of the overlay is improved, and wear occurs as a phenomenon that the thickness of the overlay decreases. On the other hand, in Non-Patent Document 2, as the amount of MoS _{2 is} increased, the overlay is worn out and the area ratio where the underlying aluminum alloy is exposed increases. In addition, the overlay is partially worn away and the underlying aluminum alloy is exposed, even in metallic overlays such as lead electroplating. Metal overlays with good compatibility tend to wear more, and this tendency is the same for solid lubricant overlays. Familiarity with solid lubricant overlay ・ The main characteristic of wear is that the crushing wear of the solid lubricant is inherently achieved only by the cleaving wear, and it is ideal that only the solid lubricant is worn, but the solid lubricant is retained. The resin to be worn will also wear away. That is, polyamideimide resin and the like are excellent in wear resistance, but wear occurs nevertheless.
(C) Fatigue resistance The solid lubricant overlay enhances the fatigue resistance of the underlying aluminum alloy (Non-Patent Documents 1, 4.3 and Non-Patent Documents 2, 3.1 (2)). That is, an aluminum alloy with a solid lubricant overlay is less likely to crack the alloy itself (lining) than an aluminum alloy without a solid lubricant overlay.
(D) Aluminum alloy for slide bearing The solid lubricant overlay is considered to be effective for aluminum alloys having a wide range of compositions disclosed in Patent Document 2. Of course, the properties of the aluminum alloy are affected by the composition, but the effects such as seizure resistance and fatigue resistance improvement due to the overlay are not improved or deteriorated by the specific aluminum alloy composition.
(E) Binder resin Polyamideimide resin has the best performance, but other resins including engine metal can be used according to application requirements.

Patent Document 1: Japanese Patent Publication No. 62-42983 Patent Document 2: Japanese Patent Laid-Open No. 4-83914 Patent Document 3: Japanese Patent Laid-Open No. 2002-61652 Patent Document 4: Japanese Patent Laid-Open No. 2004-263727

Non-Patent Document 1 :: Tribology Society of Japan, Tribology Conference Proceedings, Tokyo 1999-5 “Development of plain bearing material with solid lubricating overlay” (1st report) A13
Non-Patent Document 2: Tribology Society of Japan, Tribology Conference Proceedings, Tottori 2004-11 “Tribology of Sliding Parts at Toyota: 1A3

The present inventors investigated the bearing performance of a polyamideimide resin to which a coupling agent has been added in order to improve the adhesion between the resin and the aluminum alloy. As a result, a certain degree of adhesion improvement effect was observed. On the other hand, if the coupling agent is not added or the aluminum alloy base treatment is not performed, the wear of the overlay is likely to occur during the bearing performance test.

The composition of a general aluminum alloy for plain bearings is 1-20% Sn, 0.5-12% Si, the balance Al and unavoidable impurities. As an optional additional component, 0.5% or less Cr , 3% or less of Cu, 0.5% or less of Zr, and 0.1% or less of Ti. As a result of investigating the performance of a slide bearing with a polyamideimide-solid lubricant or solid lubricant + hard particle overlay by changing the component content within the above composition range, the present inventors have obtained the same findings as in the above (d). It was. However, when the amount of Fe conventionally contained as an inevitable impurity in an amount of less than 0.20% is intentionally added to the aluminum alloy having the above composition, the resin adheres to the aluminum alloy (lining) of the overlay with a solid lubricant. It has been found that the property is improved to a level equivalent to that of the conventional ground treatment.
Therefore, an object of the present invention is to improve the adhesion of a resin to an Al—Sn—Si based aluminum alloy which is a base of a solid lubricant or a solid lubricant + hard particle overlay, and to secure bearing performance. .

The slide bearing according to the present invention contains 1 to 20% of Sn, 0.5 to 12% of Si, and more than 0.20% and less than 2.0% of Fe, and the balance is Al and inevitable. At least one solid lubricant selected from MoS ₂ , PTFE, graphite, WS ₂ , h-BN and Sb ₂ O ₃ is coated on the surface of the aluminum alloy rolled plate made of impurities with polyamideimide [PAI] resin, polyimide An overlay bonded with a binder made of at least one resin selected from a resin, a phenol resin, a polyacetal resin, a polyether ether ketone resin, a polyphenylene sulfide resin, and an epoxy resin is provided. Hereinafter, the present invention will be described in detail.

In the aluminum alloy for sliding bearings of the present invention (hereinafter abbreviated as “aluminum alloy”), Sn is an element imparting lubricity, and if the content (mass%, the same applies hereinafter) is less than 1%, On the other hand, if it exceeds 20%, mechanical properties become poor due to a decrease in strength and melting point due to the soft Sn phase, resulting in deterioration of wear resistance and the like. The Sn content is preferably 2 to 18%.

In the aluminum alloy of the present invention, Si is crystallized as an Al—Si eutectic at the time of casting, and then is finely dispersed in the aluminum matrix as Si particles by rolling of the cast plate to impart wear resistance. The size of the Si particles is not particularly limited, but the average particle size is preferably 2 μm or more and the maximum particle size is preferably 12 μm or less. A preferable Si content is 2 to 7%.

The present inventors performed the following test regarding the adhesiveness between the resin and the metal plate.
(1) Specimen (a) A plate obtained by degreasing the surface of an aluminum alloy rolled plate produced by a normal method.
(B) Degreasing the surface of a low-carbon steel plate used for the back metal of ordinary bimetal slide bearings
Board.
(2) Resin Polyamideimide resin was applied to each of the test materials 1 (a) and (b) and baked at 180 ° C. to form a resin coating film having a thickness of about 6 μm.
(3) Test method The resin coating film was scratched with a cutter knife to give a grid-like crease.
(4) Evaluation and Results Minute peeling occurred on both sides of the straight scissors of the specimen 1 (a). From this result, it was found that aluminum has lower resin adhesion than iron.

Since iron is less oxidized than aluminum and has a higher surface activity with the resin as described above, an amount of Fe exceeding 0.20%, which is larger than the conventional impurity level, is added to the Al—Sn—Si based alloy. Addition of can improve the adhesion of the resin to the aluminum alloy. In addition, Fe dissolved in the Al matrix does not exhibit its original properties, but because Fe does not have a solid solubility in Al, Fe exists as fine particles to increase the activity with the resin. The above amount of Fe is added.
In addition, when the solid lubricant overlay is partially worn away, the mating shaft and the lining come into direct contact. Fe, however, does not impart bearing characteristics like Sn and Si, but is similar to the steel of the mating shaft. Since the phase that causes sliding of the material increases, the Fe content needs to be 2.0% or less.

  Furthermore, the aluminum alloy according to the present invention can contain at least one of (a) 0.5% or less of Cr and 3% or less of Cu in mass%. Among these elements, Cr forms an Al—Cr-based intermetallic compound and improves the strength of the aluminum matrix. If the Cr content exceeds 0.5%, it is segregated in the aluminum matrix, resulting in a decrease in rollability and the like. Cu reinforces the matrix of the aluminum alloy and increases heat resistance. Cu is also taken into the Fe phase and increases its hardness. However, if the amount of Cu exceeds 3%, it is not preferable because cracks occur during rolling due to a decrease in rolling properties.

Furthermore, the aluminum alloy according to the present invention includes (b) at least one of Mg, Ag, and Zn in a total amount of 8% by mass or less, and (c) at least one of Zr, Mn, V, Sc, Li, and Ni. The total amount of seeds or more can be 0.5% by mass or less. (B) Mg, Ag, Zn brings about solid solution strengthening. However, if the total content exceeds 8% by mass, the performance deteriorates due to the formation of intermetallic compounds, precipitation and toughness reduction due to crystallization of added elements. Therefore, it is not preferable. Further, at least one of Zr, Mn, V, Sc, Li and Ni in (c) can be reduced to 0.5% by mass or less. Zr, Mn, V, Sc, Li, and Ni cause precipitation strengthening, but if the total amount exceeds 0.5% by mass, the effect of improving the strength cannot be obtained due to coarsening and segregation of the precipitated particles, which is not preferable.
In addition to the basic components and additive elements described above, a small amount of impurities such as Pb, In, Bi, which are inevitably brought about from bullion and scrap materials. Ti and B are usually finer agents for Al crystal grains. However, in the aluminum alloy of the present invention, since the fine crystal grains are not related to Fe phase formation, a total amount of 0.5% or less is allowed as an impurity. The

The solid lubricant overlay is conventionally known, and the resin is at least one selected from polyamide imide [PAI] resin, polyimide resin, phenol resin, polyacetal resin, polyether ether ketone resin, polyphenylene sulfide resin, and epoxy resin. More than one species can be used, but polyamide imides, especially aromatic polyamide imides are preferred.

As the solid lubricant, at least one solid lubricant selected from MoS ₂ , PTFE, graphite, WS ₂ , h-BN and Sb ₂ O ₃ can be used, and MoS ₂ is most preferable. The proportion of solid lubricant in the overlay is 30-70 vol% and the thickness of the solid lubricant-overlay is 1-50 μm.

In the present invention, hard particles can be used together with the solid lubricant. The hard particles are at least one selected from SiC, Al ₂ O ₃ , TiN, AIN, CrO ₂ , Si ₃ N ₄ , ZrO ₂ , Fe ₃ P, Fe ₂ O ₃ and FeO. The proportion of hard particles in the overlay is preferably 0.1 to 5% by mass, and the average particle size of the solid lubricant is preferably 2 μm. The thickness of the overlay having the above composition is preferably 10 μm.

In the plain bearing with a solid lubricant overlay according to the present invention, since the overlay has excellent adhesion to the lining and is difficult to peel off, the overlay proposed by the present applicant in Patent Documents 2 to 4 and Non-Patent Document 1 is proposed. As described below, the bearing characteristics resulting from the above can be sufficiently exhibited.
(I) Familiarity The resin that holds the solid lubricant particles adheres closely to the lining and is difficult to peel off, so that the familiarity with the solid lubricant is sufficiently and rapidly exhibited. For this reason, fluid lubrication is realized quickly and seizure resistance is improved.
(B) Wear resistance Wear due to peeling of the solid lubricant overlay is less likely to occur. Also, even if peeling occurs, the solid lubricant overlay does not peel in large pieces of about several mm ^{2 in} area. For this reason, large peeling pieces do not enter the sliding surface and cause seizure.
(C) Fatigue resistance Fe does not directly improve the fatigue resistance of Al-Sn-Si alloys, but it can be avoided that stress is concentrated on the exposed aluminum alloy due to the peeling of the overlay.

Example 1
An aluminum alloy having the composition shown in Table 1 was continuously cast into a plate having a thickness of (15) mm, cold-rolled into a thin plate, and then the aluminum alloy was pressure-bonded to a back metal (SPCC steel plate) to obtain a bimetal. These bimetal materials were used to process bearings.
Polyamideimide resin (product of (Hitachi Chemical Co., Ltd.)) and MoS ₂ powder are prepared as raw materials for the solid lubricant overlay, blended so that MoS _{2 is} 40 vol% and the remainder is polyamideimide resin, and an aluminum alloy bearing (degreasing treatment) However, no surface treatment such as pickling was applied), and baking was performed at 180 ° C. to form a solid lubricant overlay having a thickness of about 6 μm.

The sliding characteristics of an aluminum alloy rolled sheet with a solid lubricant overlay were measured by the following method.
Fatigue resistance test (A) Test machine: Reciprocating load test machine (B) Rotational speed: 2000 to 3000 r. p. m
(C) Test temperature (bearing back surface temperature): 160 ° C
(D) Counterpart material: S55C induction hardening (e) Lubricating oil: CF-4 10W-30
Seizure resistance test (A) Test machine: Static load test machine (B) Rotational speed: 1300 to 8000 r. p. m
(C) Test temperature (oil supply temperature): 160 to 180 ° C
(2) Load: 5MP gradually increasing (e) Counterpart material: S55C induction hardening (f) Lubricating oil: SN 0W-20
The test results are shown in Table 1.

Remarks:
In Table 1, the unit of “average particle diameter” is μm. The unit of “number” is the number per μm ² . The unit of “fatigue surface pressure” and “seizure surface pressure” is MPa.

From Table 1, the range of the content of Sn, Si, Cu, Cr, Zr, and Ti is changed in the examples of the present invention, but by adding Fe, fatigue resistance and seizure resistance are good. I understand that. On the other hand, although the component ranges of Sn and the like similarly changed in Comparative Examples 6 to 8, fatigue resistance and seizure resistance are poor because the Fe amount is small. Comparative Example 9 is a comparative example in which the Fe content is 2.5%, and is inferior in fatigue resistance and seizure resistance.

The aluminum alloy plain bearing with a solid lubricant overlay of the present invention can be used for a half metal bearing, a bush, a thrust washer and the like.

Example 1
An aluminum alloy having the composition shown in Table 1 was continuously cast into a plate having a thickness of 15 mm , cold-rolled into a thin plate, and then the aluminum alloy was pressure-bonded to a back metal (SPCC steel plate) to obtain a bimetal. These bimetal materials were used to process bearings.
Polyamideimide resin (product of Hitachi Chemical Co., Ltd.) and MoS ₂ powder are prepared as raw materials for the solid lubricant overlay, blended so that MoS _{2 is} 40 vol%, and the remainder is polyamideimide resin. Applied to the surface but without any surface treatment such as pickling) and baked at 180 ° C. to form a solid lubricant overlay having a thickness of about 6 μm.

Claims (8)

An aluminum alloy rolled sheet containing 1 to 20% Sn, 0.5 to 12% Si, and more than 0.20% to 2.0% Fe, and the balance being Al and inevitable impurities. On the surface, at least one solid lubricant selected from MoS ₂ , PTFE, graphite, WS ₂ , h-BN and Sb ₂ O ₃ is polyamideimide resin, polyimide resin, phenol resin, polyacetal resin, polyether ether A plain bearing provided with an overlay bonded with at least one binder selected from a ketone resin, a polyphenylene sulfide resin, and an epoxy resin. The plain bearing according to claim 1, wherein a ratio of the solid lubricant in the overlay is 30 to 70 vol%. The overlay further comprises at least one hard material selected from SiC, Al ₂ O ₃ , TiN, AIN, CrO ₂ , Si ₃ N ₄ , ZrO ₂ , Fe ₃ P, Fe ₂ O ₃ and FeO. The plain bearing according to claim 1, wherein the plain bearing is contained. The plain bearing according to claim 3, wherein a ratio of the hard material in the overlay is 0.1 to 5 mass%. The slide bearing according to any one of claims 1 to 4, wherein the aluminum alloy rolled plate is formed by cold rolling a continuous cast plate. The aluminum alloy has a mass percentage of (ii) at least one of 0.5% or less of Cr and 3% or less of Cu, and (b) at least one of Mg, Ag, and Zn in a total amount of 8 mass. % Or less, (C) One or two of (A), (B) and (C) having a total amount of 0.5% by mass or less of at least one of Zr, Mn, V, Sc, Li and Ni The plain bearing according to any one of claims 1 to 5, further comprising Ti and B as an inevitable impurity in a total amount of 0.5% by mass or less. A slide bearing comprising a clad material in which the aluminum alloy for a slide bearing according to any one of claims 1 to 6 and a carbon steel such as SPCC or SPHC are pressed by cold rolling. 8. A plain bearing according to claim 7, wherein a surface in contact with the mating shaft is machined.