JP2950478B2 - Plain bearing alloy - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sliding bearing alloy applied as an overlay to a bearing of an internal combustion engine.
This is related to Sn-based bearing alloys.

(Prior Art) Conventionally, a Pb-based overlay with or without Ni or Cu plating on a kelmet bearing is commonly performed on a kelmet bearing. Pb-based overlays include ternary alloys such as Pb-Sn-In based overlays such as Pb-10% Sn-8% In and Pb-Sn-Cu based overlays such as Pb-12% Sn-2% Cu. is there. Further, Pb-5-20% Sn-0.05-10% I disclosed in Applicant's U.S. Pat.
n · Tl-0.5 to 5% Sb, Mn, Bi, Ni, Cu, Ca, Ba quaternary alloys are available.

On the other hand, the following techniques are known for Sn-based bearing alloys.

British Patent No. 702188 discloses that an aluminum bearing alloy is plated with Cu as an intermediate layer, and then an Sn-based overlay alloy is electroplated thereon. According to the description of this patent, since the Sn of the overlay reacts with the Cu of the intermediate layer at a high temperature to form an intermetallic compound and adversely affect the life of the joint, the thickness of each plating layer is limited in order to prevent this. is necessary. Sn-based overlay alloys are optionally composed of 30% or less of Sb, 15% or less of Cu, 10% or less of Ni, and 20% or less of Zn.
Contains more than one species.

JP-A-1-307512 discloses that 0-15% of Cu and 0-20% of
Disclose an overlay alloy containing Sb and consisting of the balance Sn,
The feature is that by providing a mixed layer of any of Ni, Fe, Co and the overlay layer between the overlay alloy layer and the aluminum bearing alloy layer with a thickness of 0.5 μm or less,
Eliminates the drawbacks of applying an overlay on the intermediate layer by plating (seizure of the shaft and bearing when the overlay wears out), and at the same time, providing the overlay directly on the bearing without the intermediate layer (the overlay layer is durable) Inferiority).

JP-A-53-141614 discloses that 、 13% of Sb, ９9% of Cu,
2% Ni, 0.005-0.5% Co, ~ 15% Cd, ~ 2% Mn, 0.00
Disclosed is a bearing alloy comprising 1 to 0.5% of Cr and the balance of Sn. The feature thereof is that by adding a small amount of Co together with Cr, tensile strength is increased without impairing flexibility.

(Problem to be Solved by the Invention) In U.S. Pat.
It is pointed out that ternary overlays such as u-based and Pb-Sn-In-based systems have good conformability, but lack sufficient fatigue resistance, engine lubricity, especially corrosion resistance to degraded oil, and seizure resistance. did. Then, in the above-mentioned U.S. patent, a quaternary overlay was proposed to achieve an improvement in overall bearing performance, but subsequent studies have shown that Pb-based overlays still have poor corrosion resistance even in quaternary systems, especially corrosion resistance to deteriorated lubricating oil. It turned out to be enough.

Generally speaking, Pb-12% Sn-2% Cu, Pb-10% Sn-8
It is known that Sn-based overlays are less compatible than Pb-based overlays such as% In, but are superior in corrosion resistance. However, Sn-based overlays tend to have lower seizure resistance than Pb-based overlays, and even with Sn-based alloys containing conventionally known additives, seizure resistance equivalent to that of Pb-based overlays has not been achieved. Absent.

Therefore, the present invention has better corrosion resistance, wear resistance and fatigue resistance than the conventional ternary Pb overlay, and has the same corrosion resistance, wear resistance and fatigue resistance as the conventional Sn-based overlay, and It is an object of the present invention to provide an overlay sliding bearing alloy having excellent characteristics.

(Means for Solving the Problems) The present invention provides a plain bearing alloy having the following four compositions.

(1) A sliding bearing alloy containing 0.1 to 25% by weight of In (hereinafter, percentages are by weight unless otherwise specified), and the balance is composed of unavoidable impurities and Sn.

(2) 0.1 to 25% by weight of In, and Sb, Cu, Ag, Ni, Zn and A
1. A sliding bearing alloy containing 0.01 to 15% of at least one of l and the balance consisting of unavoidable impurities and Sn.

(3) A sliding bearing alloy containing 0.1 to 25% by weight of In and 0.1 to 20% of Pb, the balance being unavoidable impurities and Sn.

(4) 0.1 to 25% of In, Sb, Cu, Ag, Ni, Zn and Al (hereinafter referred to as S
at least one of b)
A plain bearing alloy containing 0.01 to 15% and 0.1 to 20% of Pb, the balance being unavoidable impurities and Sn.

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

The common composition of the sliding bearing alloy of the present invention is 0.1 to 25% In.
Is contained. Sn itself is harder than Pb,
Poor adaptability, high friction coefficient with steel and cast iron of mating shaft, and poor affinity with oil. Solid solution in Sn
Sn-In made by adding In and In to Sn
Reduces the hardness, improves conformability and friction properties, and improves lipophilicity. As a result, seizure resistance of the Sn-based alloy is improved. If the amount of In is less than 0.1%, the solid solution amount of In is small, and the above-mentioned properties of Sn do not change. Therefore, the amount of addition must be at least 0.1%. On the other hand, if the amount of In exceeds 25%, the melting point of the Sn-In alloy becomes too low, and the load resistance and fatigue resistance decrease. Therefore, the upper limit of the amount of In needs to be 25%. When the amount of In added is 15% or less, the melting point is 205.
° C or more, and a decrease in performance due to a decrease in melting point can be avoided. When the In content is 0.1 to 8%, the melting point is 205 to 23.
It is kept at 2 ° C and at 0.1-5% the melting point is kept at 224.5-232 ° C. The relationship between the melting point of the amount of In added and will be described later.
The amount of In added is determined in consideration of the amounts of Sb, Cu, etc. (both of which increase the melting point of the Sn alloy) and the operating temperature of the overlay. For example, for a bearing used at a high temperature of 170 ° C. at the back surface temperature of the bearing, an In content of 0.1 to 5% is preferable.

The sliding bearing alloy of the present invention has a preferred additive component of 0.1.
Contains 01 to 15% of Sb (additional component represented by Sb) and / or 0.01 to 20% of Pb.

The melting point of the Sn-based alloy is lower than that of the Pb-based alloy, and the addition of In slightly shifts the composition to a lower melting point, resulting in lower fatigue resistance. When Sb is added to the Sn-In alloy, the added element dissolved in the Sn-Inγ phase or the Sn-In solid solution raises its melting point, and the InSb (Mp = 530 ° C.), SnSb (β
Phase, Mp = 325 ° C). Therefore, the melting point of the entire alloy can be increased, and performance degradation due to the low melting point can be avoided. Further, the above-mentioned intermetallic compound is finely dispersed in the vicinity of the crystal grain boundary of the Sn-Inγ phase or the Sn-In solid solution to strengthen the precipitation of the matrix, thereby improving the fatigue resistance and the wear resistance. These deposits are not initially generated when the overlay is made by electroplating or dry plating, but are generated by subsequently applying heat to the overlay. When an overlay is produced by hot-dip plating, a precipitate is formed from the beginning, but electroplating is preferred as a method of producing the overlay because the precipitate is coarse and the precipitation strengthening is small.

The addition amount of Sb and the like is 0.01 to 15%. The amount of Sb added is 0.01
%, The properties of the Sn-In gamma phase or Sn-In solid solution do not change, so the addition amount must be 0.01% or more. If the added amount of Sb exceeds 15%, the alloy becomes hard and brittle, and the conformability decreases. Therefore, the upper limit of the added amount of Sb is 15%.

When fatigue resistance is important in bearing characteristics, Sb should be 3%
When the wear resistance is emphasized, it is preferable that Sb be 8% or less. The reason is that, in the case of Sb, the size and amount of hard SnSb (β 'phase) increase as the amount of Sb increases, and when it exceeds 3% Sb, the wear resistance increases but the fatigue resistance decreases. This is because it tends to decrease. 3% more
If the content exceeds Sb, the hardness becomes too hard, and the seizure resistance is reduced. Therefore, an alloy exceeding 3% Sb is desirably used for an application in which wear resistance is particularly important.

Additive elements other than Sb, such as Cu, Ag, Ni, Zn, and Al, also act similarly to Sb. However, the resulting compound and the upper limit of the preferable addition amount are different from those of Sb as follows.

Cu is Cu ₃ Sn (ε phase, Mp = 600 ° C. or higher), CuIn (Mp = 600
° C) and compounds such as Cu ₆ Sn ₅ (η 'phase, Mp = 415 ° C). The preferred upper limit is 3%.

Ag produces compounds such as Ag ₃ Sn (Mp = 480 ° C.) and AgSnIn. The preferred upper limit is 5%.

Ni produces compounds such as Ni ₃ Sn ₄ (Mp = 795 ° C.). The preferred upper limit is 3%.

Zn is a eutectic alloy and precipitates alone. The preferred upper limit is 1%.

Al precipitates solely in an 8-crystal alloy. The preferred upper limit is 1%.

Pb improves conformability and seizure resistance. If the amount of Pb is less than 0.1%, the effect is not obtained.
%, The melting point becomes 200 ° C. or less, and the applications that can be used as bearings are extremely limited. When Pb is used in an addition amount (2.5% or less) for forming a Sn-In solid solution, the above-described effect is improved, and the corrosion resistance to degraded oil does not matter.

The structure of a bearing using the bearing alloy according to the present invention is as follows. First, kelmet (composition example, Cu-22% Pb-3% Sn) is sintered to a thickness of 0.25 mm on the back metal (SPCC) and then finished. On top of that, a 2μm thick Ni
15μ of the bearing alloy (overlay) of the present invention through plating
m bearing. Next, an aluminum alloy (for example, 0.3 mm thick, composition Al-4.5% Zn-1% Cu
−2% Si), and then press-molded to form a bearing in which the bearing alloy (overlay) of the present invention is applied to the aluminum alloy layer to a thickness of 15 μm via a Cu plating layer having a thickness of 2 μm. Further, an aluminum alloy (for example, a thickness of 0.3 mm, a composition of Al-12% Sn-3% Si-1% Cu-0.3% Mn-
1.5% -Pb), and the aluminum alloy layer is directly coated with the bearing alloy (overlay) of the present invention to a thickness of 5 μm to form a bearing.

Next, plating conditions when the bearing alloy of the present invention is prepared by plating will be described.

Sulfuric acid bath of Sn plating or Sn-Cu, Ni plating Bath temperature 20 in a plating bath containing stannous sulfate 40 g /, sulfuric acid 60 g /, cresol sulfonic acid 40 g /, gelatin 2 g /
° C., performing Sn plating at a current density of 2A / dm ^2. Sn-Cu or Sn
-When plating Ni, add an appropriate amount of copper sulfate or nickel sulfate to the plating bath.

Boron acid bath for Sn plating or Sn-Sb plating perform Sn plating in dm ^2. Sn−
When plating with Sb, an appropriate amount of antimony fluoride is added to the plating bath.

Sn-Pb plating bath Stannous fluoride 200g / Lead tin fluoride 200g /
, Boric acid 100g /, hydroquinone 4g /, peptone 0.5g / bath temperature 20 ℃, current density 3A /
performing a Sn-Pb plated with dm ^2.

Sn-Ag plating bath silver sulfonate 15 g /, acid tin 10 g /, potassium iodide 350 g /, bath temperature 30 ° C. in a plating bath containing organic additives 5 g /, at a current density of 1.5A / dm ² Sn-Ag Perform plating.

After the above plating, In plating is performed in an indium sulfanmate plating bath at a bath temperature of 30 ° C. and a current density of 1.5 A / dm ² .

After or before 60-180 ° C, preferably 80 ° C, 5
Heat treatment is carried out for up to 30 minutes, preferably 15 minutes.

As another method, a Sn-In alloy can be produced by a single treatment using a bath of tin sulfamate and an indium sulfamate. Sb, Pb, etc. are added to the plating bath as needed.

Sn-In by dry plating such as ion plating, sputtering, and vapor deposition as another method.
An (Sb / Pb) -based alloy can be produced.

(Action) The above data is the result of evaluating the bearing characteristics of various overlay alloys under the conditions of the examples. By comparing these bearing characteristics, the Sn-7% In-7% Sb-based overlay alloy of the present invention has better corrosion resistance, wear resistance and fatigue resistance than the conventional ternary Pb alloy overlay, and Traditional
The seizure resistance and fatigue resistance are superior to that of the Sn-based overlay alloy, and it can be seen that the conformability of the overlay alloy of the present invention is intermediate between the conventional Pb-based overlay and the conventional Sn-based overlay.

 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 kermet (composition-Cu-22% Pb-3% Sn, thickness: 3 μm) through a Ni plating layer having a thickness of 3 μm.
0.3 mm). Kelmette was formed on a 1.2 mm thick steel plate.

 The performance of the bearing was measured by the following test method.

Abrasion resistance Test bearings are incorporated as bearings for a 1600cc gasoline engine (using a cast shaft (FCD70) and unleaded gasoline).
rpm full load; 500 hours continuous operation; lubricating oil: SAE7.5W30, SE
Grade, oil every 100 hours, oil pan temperature = 120 ℃;
Was measured after 500 hours of operation.

Seizure resistance Using a journal type seizure tester, rotation speed 1500 rpm, surface pressure 5
0 kg / cm ² was sequentially applied every 30 minutes, and the baking surface pressure was measured. The shaft is S50C hardened shaft, the lubricating oil is SAE7.5W30, SE class is 140 ℃
Refueled.

Fatigue resistance 3000 rpm, surface pressure 600 kg / cm ² with reciprocating load tester
The load was repeatedly applied to the test material 3 × 10 ⁶ times under the conditions described above, and the area where fatigue occurred was measured. The shaft was a S50C quenched shaft, and the lubricating oil was SAE7.5W30, SE grade, and was lubricated at 120 ° C.

Corrosion test Incorporate a test bearing as a bearing for a 1600cc gasoline engine (quenched shaft (S50C), using leaded gasoline), 5600rp
m Amount of wear; 300 hours continuous operation; Lubricating oil; SAE10W30, SD class, no oil exchange, oil pan temperature = 120 ° C;

 The test results are shown in Table 1.

(Effect of the Invention) As described above, the sliding bearing alloy according to the present invention is Sn alloy.
The common feature is that In is added to the base alloy, and the lack of familiarity, high coefficient of friction, and lack of lipophilicity of Sn are eliminated, and the excellent corrosion resistance of Sn is utilized. Therefore, the sliding bearing alloy of the present invention is suitable for applications where corrosion resistance is particularly required.

On the other hand, the addition of In tends to lower the melting point of the Sn-based alloy, but this can be suppressed by the addition of Sb or the like, and the performance such as load resistance can be improved. Furthermore, the conformability can be improved by adding Pb.

Continuation of the front page (56) References JP-A-50-141537 (JP, A) JP-A-47-6755 (JP, A) JP-A-63-28839 (JP, A) JP-A 1-237095 (JP) , A) JP-A-1-307512 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C22C 13/00 F16C 33/12

Claims (4)

(57) [Claims] 1. A sliding bearing alloy containing 0.1 to 25% by weight of In and the balance consisting of unavoidable impurities and Sn. 2. In 0.1 to 25% by weight of In, and Sb, Cu, Ag, Ni, Zn
A sliding bearing alloy containing 0.01 to 15% by weight of at least one of Al and Al (the total amount when two or more are added), and the balance consisting of unavoidable impurities and Sn. 3. A plain bearing alloy containing 0.1 to 25% by weight of In and 0.1 to 20% by weight of Pb, the balance being unavoidable impurities and Sn. 4. In 0.1-25% by weight of In, Sb, Cu, Ag, Ni, Zn and A
l at least one of 0.01 to 15% by weight (total amount when two or more types are contained), and 0.1 to 20% by weight of Pb,
A sliding bearing alloy comprising a balance of unavoidable impurities and Sn.