JP3055069B2 - Overlay alloy for plain bearings - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overlay alloy for a slide bearing, and more particularly, to a slide bearing for an internal combustion engine, particularly a slide sliding on a crankshaft or the like. The present invention relates to a Pb-based overlay alloy having excellent corrosion resistance and fatigue resistance in a bearing.

[Conventional technology]

Plain bearings for internal combustion engines are cylindrical bushing, half metal,
There are thrust bearings and the like, and each part constituting these is usually referred to as a back metal and a lining made of a steel plate, and is a slide bearing alloy bonded to the back metal and an overlay bonded to the lining. The overlay alloy is lead or a soft alloy containing lead and tin as main components, and its properties are improved by devising additional components.

According to Japanese Patent Publication No. 39-22498, a lining made of a copper-lead alloy is provided with In2 to 10% and C as an optional additive component.
u0.1-3%, Te0.001-0.25%, Ag0.5% or less, Sb0.5%
2. Description of the Related Art A plain bearing containing one or more of the following, and having an overlay alloy composed of Pb with the balance being bonded, is known. According to the description in this specification, In, Cu, and Te have an effect of improving the corrosion resistance of a cast alloy.

Further, according to JP-A-61-266544, In1 to 10
An overlay alloy is known which contains 0.1% to 6% of Cu, 8% or less of Sn as an optional additive component, and the balance being Pb. According to the description in this specification, Cu has the effect of miniaturizing the alloy surface layer and delaying the diffusion of In into the underlying alloy,
As a result of these actions, corrosion resistance and fatigue resistance are improved. In
Improves the corrosion resistance, and Sn significantly improves the corrosion resistance under interaction with In.

Next, according to JP-A-59-205442 filed by the applicant of the present invention, according to In and / or Tl10, 15%
%, One or more of Cu, Sb, Mn, Ni, Ca, Bi, and Ba are known. According to the description in this specification, In and Tl mainly improve corrosion resistance, and Cu and the like form an intermetallic compound, and mainly improve fatigue resistance.

In recent years, the operating conditions of internal combustion engines have become increasingly hotter and heavier, and their service periods have been prolonged, so that the performance required for overlays has become increasingly sophisticated. For example, the oil temperature near the sliding surface may rise to a high temperature of 130 to 180 ° C. in accordance with the recent increase in the rotation speed and the output of the internal combustion engine.

Furthermore, in internal combustion engines, soot (carbon fine particles),
There is a problem of corrosion due to reaction products of oil and fuel components being mixed into engine oil and coming into contact with the overlay. The reaction products are SO ₄ ^2- , fatty acids, halides (C
l, compounds such as Br), NO ₃ ^- contains the.

The problem of the additive component of the overlay used under the above-mentioned conditions will be examined.

Under high temperature conditions, Sn in the overlay alloy diffuses in the direction of Ni plating, so that Sn is depleted in the overlay, and its corrosion resistance and fatigue resistance are reduced. Also, under the high temperature conditions described above, the In phase in the overlay melts,
It leads to peeling and burning of the overlay.

Further, Cu and In are added for the purpose of improving the performance of the Pb-Sn based overlay, but since In is easily attacked by a halide, Cu forms a compound with SO ₄ ⁻ and NO ₃ ⁻ . ,
Corrosive wear of the overlay occurs. Further, there is a disadvantage that the melting point is reduced when a large amount of In is contained.

Further, if Cu is contained in a large amount, the fatigue resistance and conformability deteriorate, so that the amount of addition is limited (about 5% or less). If the content of Sn is too large, the compound layer is enlarged by diffusion to the interface of the Ni plating, and the melting point is lowered as in the case of In.

[Problems to be solved by the invention]

The Cu added to the overlay alloy disclosed in JP-A-59-205442 also contains Ni when added together with Sn under high-temperature operating conditions.
Or diffuses during lining and depletes in the overlay. For this reason, this known overlay cannot exhibit sufficient fatigue resistance in recent use conditions of an internal combustion engine. Furthermore, the simultaneous addition of In and Sn to this known overlay significantly lowers the melting point or solidus of the alloy. For this reason, the diffusion of Sn and Cu described above becomes very likely to occur. In addition, the lifetime of the overlay is shortened due to the dissolution of Cu.

The overlay known in JP-A-61-266544 is made of Cu and
Since In is contained as an essential component, the phenomena already described for these components occur.

The overlay in Japanese Patent Publication No. 39-22498 was the subject of an application for a priority claim in 1960, and at that time the use of the internal combustion engine was much slower than at present. For example,
In the specification of this application, there is no reference to the use of Ni plating, and conversely, it is considered that In in the overlay is diffused in the lining and Cu in the lining is actively diffused in the overlay. Seems to be. Ni plating is used in the above two Japanese Patent Publications which are newer than this application, which reflects that the operating conditions of the internal combustion engine at the time of these applications were much more severe than at the time of 1960. ing.

As a result of the above study, it has been clarified that the overlays which have hitherto been known do not meet the usage conditions of internal combustion engines in recent years.

[Means and actions for solving the problem]

The present inventors have studied means for drastically improving the corrosion resistance and fatigue resistance of the overlay, and as a result, have reached an overlay alloy having the following composition.

That is, by weight, more than In3 and 10% or less, Sn2-12%,
This is an overlay alloy containing more than 1 to 15% of Ag and the balance substantially consisting of Pb and impurities.

 Hereinafter, the configuration of the present invention will be described.

Pb is a main component of the alloy of the present invention and exhibits conformability, which is a basic performance required for overlay.

Sn improves corrosion resistance and fatigue resistance. If the content is less than 2%, there is no effect, and if it exceeds 12%, the conformability is lowered and the melting point is lowered. The preferred Sn content is 4 to 8%.

In addition to exhibiting conformability, In forms a solid solution with Pb to greatly increase corrosion resistance and slightly increase fatigue resistance. In content 3
% Or less, there is no effect of improving corrosion resistance. On the other hand, if it exceeds 10%, the melting point becomes low and performance at high temperatures, especially abrasion resistance, is deteriorated, and corrosion resistance to corrosive media such as halides is reduced. to degrade. The preferred content of In is 5 to 5.
9%.

Any one or more of Sb, Mn, Bi and Ag (hereinafter, may be collectively referred to as “Sb etc.”) is In-Sb, In-Mn, In-Ag
Intermetallic compounds such as these are formed and precipitated to maintain wear resistance, prevent the growth of crystal grains at high temperatures, and prevent reduction in strength and fatigue resistance. When the added amount of Sb or the like is 1% or less, it acts only as an impurity.
%, The softness of the Pb-In solid solution is inhibited, and the conformability is reduced. Preferred amount of Sb etc. is 1.5-7.5%
It is.

Components other than the above components are impurities. Typical impurities are Cu, Fe, Sn, Zn and the like. These impurities are preferably 0.2% or less in total or alone. In particular, Cu has a drawback that the overlay is easily attacked by reaction products of oil and fuel, so that high load,
It is not suitable as an additive element for an overlay for a high-speed internal combustion engine.

The overlay of the present invention may be cast or electroplated,
It is manufactured by PVD such as sputtering. However,
In the casting method, since the crystal grains are coarsened, it is preferable to manufacture by an electroplating method or a PVD method. In the PVD method,
The desired component can be obtained at one time using the target of each component. It is also possible to carry out the PVD method and the electroplating method in combination.In this case, components other than In are used.
Lamination on the lining by PVD, lamination of In by electroplating, and then annealing to allow diffusion between these layers. The electroplating method is preferable from the viewpoint of cost in mass production.

The thickness of the overlay according to the present invention is determined by the conditions of use of the bearing, and is not particularly limited, but is, for example, 1 to 30 μm.
m.

Although the configuration of the entire slide bearing using the overlay according to the present invention is also not particularly limited depending on the use conditions of the bearing,
Considering the operating conditions of recent internal combustion engines, the intermediate layer of Ni, Cu, Zn, etc. is preferably provided in order to prevent the diffusion of Sn, In in the case of Cu-based lining, and is not necessarily required in the case of aluminum-based lining. May be omitted.
The material, size, shape, etc. of the lining are not limited at all, and are determined exclusively by the operating conditions of the internal combustion engine.

 Hereinafter, the present invention will be described in more detail with reference to examples.

〔Example〕

An overlay having the composition shown in Table 1 was formed by plating on a Cu-based lining via Ni plating. The plating method will be described below.

After Ni plating, water washing is performed, and then the following plating layers are laminated on the Ni plating.

Pb-Sb plating + In plating + Sn plating Pb-Sb plating (14 µm thickness) Plating bath composition Lead borofluoride (as lead ion concentration) 50 to 200 g / antimony borofluoride (as antimony ion concentration) 0.25 to 5 g / borofluoride Hydrogen acid 20-120g / Additives (hydroquinone, etc.) 1-5g / Plating conditions Liquid temperature 5-50 ° C Current density 2.0-6.0A / dm ² Rinsing In plating (1μm thickness) Sulfamic acid plating bath Indium sulfamate 40-210g / Sulfamic acid 10 ~ 60g / NaCl 15 ~ 100g / Glucose 2 ~ 25g / Triethanolamine 1 ~ 5g / Sodium sulfamate 70 ~ 320g / Liquid temperature 10 ~ 50 ° C Current density 1 ~ 10A / dm ² pH 3.8 or less Sn plating Sodium stannate 100g / ~ 150g / Sodium hydroxide 5 ~ 50g / Liquid temperature 60 ~ 85 ℃ Current density 0.6 ~ 3A / dm ² Voltage 4 ~ 6V Annealing 100 ~ 200 ℃ (In and Sn Pb-Sb plating layer According to the above method The corrosion resistance evaluation of the fabricated slide bearing specimen subjected to preliminary heat treatment in the following manner, was carried out by subsequent Sota Shikido load tester (oil used below).

Preheat treatment 180 ° C × 200 hours Heating medium: 10W-30 oil (containing 3% of inorganic acid and 3% of organic acid. Test piece is immersed and heated) The test results are shown in Table 1.

In Table 1, Samples 12, 14 to 18 do not contain Sb and have poor corrosion resistance. This is considered to be due to the fact that the strength of the test piece not containing Sb subjected to the dynamic load was reduced and the corrosion was promoted. Next, it can be seen that the corrosion resistance of Samples 13 and 19 is poor because they do not contain Sb and In but contain Cu. On the other hand, the test piece of the present invention shows good corrosion resistance.

Next, after performing the above-mentioned preliminary heat treatment on some of the above-mentioned test pieces, the following corrosion resistance test (1),
(2) was performed.

1. Corrosion resistance test (1) 4-diesel engine test Rotation speed x load: 4000rpm x full Oil temperature: 120 ° C Oil change: Every 100 hours Bearing width: 30% narrowing 2. Corrosion resistance test (1) 2 Leaded gasoline Engine 7300rpm × wot Oil: 10w-30 Oil temperature: 135 ° C The results of the corrosion resistance test (1) and the corrosion resistance (2) are shown in FIGS. 1 and 2, respectively. From these results, it is clear that the test piece of the present invention has excellent corrosion resistance.

Further, a fatigue test of some bearing test pieces was performed by the following method, and a fatigue area was measured.

Fatigue tester Surface pressure: 800kg / cm ² Oil: 7.5w-30 Oil temperature: 120 ° C The test results are shown in Fig. 3. From this figure, it is clear that the test piece of the present invention has excellent fatigue resistance.

[Effects of the Invention] As described above, since the overlay alloy for a sliding bearing of the present invention is excellent in corrosion resistance and fatigue resistance, it has suitable performance as a recent sliding bearing for an internal combustion engine.

[Brief description of the drawings]

 1 and 2 are graphs showing the results of the corrosion resistance test, and FIG. 3 is a graph showing the results of the fatigue test.

Continuation of the front page (56) References JP-A-63-6215 (JP, A) JP-A-59-205442 (JP, A) JP-A-56-84435 (JP, A) JP-B-39-22498 (JP) , B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 11/00 F16C 33/12

Claims (1)

(57) [Claims] (1) more than 10% and less than In3, Sn2 to 12% by weight,
An overlay alloy for a sliding bearing, characterized by containing more than Ag1 and not more than 15%, with the balance being practically composed of Pb and impurities.