JPH07252693A - Plain bearing having composite plated film - Google Patents

Abstract

PURPOSE:To improve wear resistance without deteriorating the fatigue characteristic of a tin-made or tin alloy-made surface layer. CONSTITUTION:A plain bearing has the tin or tin-base alloy composite plated film 1 containing a eutectoid inorganic material particle on the surface. The inorganic material particle dispersed in the plated film has <=1.5mum average particle diameter and is contained by 0.05-5vol% as a whole in the coating film and the Vickers hardness Hv of the composite plated film is 5-30. The tin-base alloy containing 0.1-25wt.% total quantity of one or more kinds of elements selected from Cu, Sb, Zn and In is suitably used as the alloy for the plated film. The bearing is provided as a laminated body composed of a steel made back plate, a bearing alloy layer 3 provided on the back plate and the composite plated film provided on the bearing alloy layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding member used as a sliding bearing for automobiles, ships, construction machines and other general industrial machines.

[0002]

2. Description of the Related Art A conventional slide bearing used in an internal combustion engine is a bimetal plate formed by joining a bearing copper alloy layer or a bearing aluminum alloy layer on a steel back metal plate, a cylindrical bush, and a half-divided metal body. In general, the bearing alloy layer is processed into a (semi-circular body) or the like, and a soft metal is coated on the bearing alloy layer as an overlay (surface layer). Here, the main functions of the overlay layer are the compatibility with the shaft such as the crankshaft, the embedding property of incorporating foreign matter mixed in the lubricating oil into the overlay layer, and the bearing function against the organic acid generated by the deterioration of the lubricating oil. Protection, that is, improvement of corrosion resistance, can be mentioned. In order to improve these functions, lead alloy overlay layers have been incorporated into US Pat.
As disclosed in Japanese Patent No. 605,149 and Japanese Patent Publication No. 22498/39, a multi-layer slide bearing having an overlay layer in which the amounts of components such as Sn, Cu, In, etc. are variously manufactured is manufactured and used. It has been. Furthermore, the inventors of the present invention have disclosed in Japanese Patent Application Laid-Open Nos. 4-325697 and 4-3318.
17, proposed a plain bearing having a lead alloy overlay layer in which inorganic particles are co-precipitated as a means for significantly improving the wear resistance of the overlay layer without impairing the function of the Pb-based alloy overlay layer.

[0003]

In recent years, the harmfulness of lead itself to the human body and the global environment has been regarded as a problem, and conversion to a highly safe tin overlay layer has been desired. However, tin alone lacks mechanical strength and wear resistance, and has the disadvantage of lacking lipophilicity with a lubricating oil. Attempts have been made to improve these drawbacks by adding Sb, Cu and the like. However, when added in excess, the melting point of the tin-based alloy overlay layer decreases, and the coarse hard intermetallic compound SbSn in the overlay layer is reduced. , Cu ₆ Sn _5, etc. are generated, the toughness of the overlay layer is impaired, and the fatigue resistance of the overlay layer is significantly reduced. Therefore, the amount of Sb, Cu, etc. added is limited, and the application of the tin-based alloy overlay is limited to a narrow range. The present invention was devised under such a technical background, without impairing fatigue resistance,
It is an object to provide a tin or lead based alloy overlay with improved mechanical strength, especially wear resistance.

[0004]

[Means for Solving the Problems and Its Action] This object is a plain bearing having a tin or tin-based alloy composite plating film on the surface thereof, which contains co-precipitated inorganic particles, and which comprises a tin or tin-based alloy. The inorganic particles dispersed therein,
A sliding bearing having an average particle diameter of 1.5 μm or less, 0.05 to 5% by volume as a whole in the plating film, and a composite plating film having a Vickers hardness of Hv5 to 30. Achieved by providing. The surface plating layer is generally formed to have a thickness of 10 to 30 μm if the slide bearing is a constituent member of an internal combustion engine for automobiles. This thickness is not limited, and there is an example in which the thickness is 50 to 100 μm when it is used under a low surface pressure such as a sliding bearing of an internal combustion engine for ships. In addition, if inorganic particles having an average particle size of 1.5 μm or less are dispersedly present in the surface plating layer, for example, when the slide bearing is the main bearing that supports the crank bearing of the internal combustion engine, it is Even when there is no lubricating oil film with the main bearing, relatively hard inorganic particles in the matrix of the surface plating layer mainly support the load and protect the entire plating layer, preventing wear of the surface plating layer. It
As the inorganic particles (non-metal particles, metal particles) to be present in the composite plating film, BN, TiN, AlN, Cu
N, Si ₃ N _{4 and} other nitrides, SiC, TiC, B ₄ C,
In addition to carbides such as TaC, fluorides such as (CF) _n and CaF ₂ , sulfides such as MoS ₂ and WS ₂ , BaSo ₄ , W,
Mo and the like can be mentioned. These inorganic particles are limited to those having an average particle size of 1.5 μm or less. Particle size is 1.5 μm
If it exceeds, the toughness of the composite plating film is lost. Also, since the hardness of the matrix is increased, the conformability, which is the most required function of the overlay of the slide bearing, is impaired, and the pressure of continuous oil film pressure fluctuation that occurs during internal combustion engine operation cannot be withstood. The composite plating film itself wears out due to fatigue. In addition, since the surface roughness of the composite plating film is increased and the friction coefficient is increased, early wear in the initial stage of operation occurs. Therefore, the average particle size of the inorganic particles is limited to 1.5 μm or less, preferably 1.0 μm or less.

The amount of inorganic particles contained in the composite plating film is limited to 0.05 to 5% by volume. This is because if the amount of the inorganic particles is less than 0.05% by volume, the effect is small, and if it exceeds 5% by volume, the toughness is lost. The most preferred amount is 0.5-3% by volume. The amount of inorganic particles (coprecipitated amount) in the composite plating film is adjusted by adjusting the amount of inorganic particles dispersed in the plating bath. The amount of co-precipitation and the amount of dispersion have a substantially proportional relationship. The matrix of the composite plating film may be tin alone, but in order to improve mechanical strength and lipophilicity with the lubricating oil, Cu, Sb, Zn,
One or more components selected from In are preferably added. If the added amount (or total amount) is less than 0.1% by weight, the effect is not exerted, and if the added amount exceeds 25% by weight, the mechanical strength at high temperature is remarkably lowered,
It increases the hardness of the composite plating film itself and reduces the conformability. Therefore, the content is 0.1 to 25% by weight. The most preferred amount is 0.5 to 20% by weight.

The hardness of the composite plating film is important as an element of the conformability as a main function of the slide bearing. When one or more components selected from Cu, Sb, Zn and In are added to tin, the matrix hardness increases,
Moreover, when the content of the inorganic particles increases, the hardness of the composite plating film itself increases. The optimum Vickers hardness for the overlay of the sliding bearing is Hv5-30, and the contents of Cu, Sb, Zn, In and the inorganic particles added to tin are adjusted so as to fall within this range.

It is preferable to interpose an intermediate plating layer having a thickness of 0.5 to 5 μm between the composite plating film and the alloy layer below the composite plating film. Alloy Co, Co alloy, Fe, Fe alloy,
It is formed of any one kind of metal selected from the group consisting of Ag, Ag alloy, Zn and Zn alloy. These intermediate plating layers are Sn, Sb, In or Zn of the composite plating film.
Has the effect of preventing the formation of a diffusion compound layer with copper of the base alloy (that is, the bearing copper alloy).

Further, it is preferable to interpose a joining metal layer between the back metal and the alloy layer for strengthening the joining of both layers, and the joining alloy layer is made of Ni, Ni alloy, Cu, Cu alloy, Al. , Al alloy, formed of a kind of metal selected from the group consisting of Al alloys. In the multi-layer plain bearing according to the present invention, it is possible to omit the layers other than the surface layer if the composite plating layer of the present invention is present.

[0009]

EXAMPLES FIGS. 1 to 7 are schematic views showing the vertical cross-sectional structure of a plain bearing according to the present invention which is provided as a surface layer of each composite plating film. FIG. 2 shows Cu-Pb.
System, Cu-Pb-Sn-based, Cu-Zn-based, SiC on the Cu bearing alloy layer 3 of the Cu-Sn-based or the like, Si ₃ N _4, (C
F) Sn—Sb, Sn—Cu, Sn containing one or more selected from inorganic particles such as _n , MoS ₂ and BN
An example in which a Sn alloy layer 1 such as -In, Sn-Zn, Sn-Sb-Cu is stacked is shown. FIG. 3 shows a steel backing 4 made of low carbon steel, high carbon steel, stainless steel, special steel, etc.
2 shows an example in which the Cu bearing alloy layer 3 and the Sn alloy layer 1 shown in FIG. 2 are laminated. FIG. 4 shows Ni, Co, Fe and Ag between the Cu bearing alloy layer 3 and the Sn alloy layer 1 in FIG.
An example is shown in which the intermediate layer 2 made of any one of them or an alloy containing them as a main component is provided. FIG. 5 shows Al-Sn.
-Based, Al-Si-based, Al-Zn-based Al bearing alloy layer 5
An example is shown in which a Sn alloy layer is laminated on the above. Figure 6
An example corresponding to the case where the Cu bearing alloy layer 3 in FIG. 4 is replaced with the Al bearing alloy layer 5 is shown. In FIG. 7, a joining layer 6 made of Ni, Al, or an alloy thereof is provided between the steel back metal 4 and the Al alloy layer 4, and an intermediate layer 2 is provided between the Al alloy layer 5 and the Sn alloy layer. It is an example.

[0010]

[Test Example 1] A copper backing having a thickness of 8 μm was plated on a steel backing, and then a sintered layer was formed by sintering copper alloy powder (Cu-23Pb-3.5Sn) to produce a bimetal. Then
The obtained bimetal is cut and subjected to a machining process to obtain a half (semicircular) plain bearing test piece (hereinafter referred to as a test piece).
Was manufactured. For the test, ordinary solvent degreasing, electrolytic degreasing, and pickling were performed in this order, and then the surface of the sintered copper alloy was plated under the following conditions. Plating conditions: normal watt Ni plating bath, bath temperature 50 ° C., cathode current density 6 A / dm
² . An Ni plating intermediate plating layer having a thickness of 1.5 μm was previously provided on the copper alloy surface, and tin sulfate 45 to 55 g / l, antimony chloride 1.0 to 1.5 g / l, sulfuric acid 100 g / l,
Using SiC (carbide) having different average particle diameters as inorganic particles in a plating bath composed of ammonium fluoride of 5 g / l, dispersed in the SiC plating bath of 25 to 50 g / l, bath temperature 25 ° C., cathode Current density 0.3 to 3 A / dm ²
Was electrolyzed to obtain a composite plating film consisting of co-precipitated inorganic particles and a basic tin alloy layer. The thickness of each layer is a composite plating film of 20 μm, a copper alloy layer of 0.3 mm, and a steel back metal layer of 1.2 mm. Table 1 shows the co-precipitation amount and the composition of the tin alloy as the plating film substrate in terms of particle size in each test conducted under different conditions. Sample Nos. 1 and 2 are examples of the present invention,
Sample Nos. 3 and 4 are comparative examples. In the embodiment of the present invention, the example in which the joining alloy layer is formed by Cu plating between the steel backing and the bearing copper alloy is shown, but the joining alloy layer may be omitted.

[0011]

[Test Example 2] The same test piece as in Test Example 1 was used and subjected to the same pretreatment (for the purpose of imparting the same plating as in Example 1) to give "zinc sulfate 350 g / l, ammonium sulfate 30 g / l. Zn plating (intermediate plating) under the plating conditions of the following composition: bath temperature 40 ° C., cathode current density 5 to 10 A / dm ² ′, tin methanesulfonate 30
˜50 g / l, methanesulfonic acid 50˜100 g / l plating bath with different average particle size Si ₃ N ₄ (using nitride as inorganic particles) 30˜100 g / l dispersed in plating solution A composite plating film was obtained in the same manner as in Example 1. Next, after performing Zn plating in the same manner as above, tin sulfate 30 to 50 g / l, copper sulfate 0.1 to 0.5 g
/ 1 and sulfuric acid 50 to 100 g / l, and 3 to 100 g / l of Si ₃ N ₄ (using nitride as inorganic particles) having different average particle diameters are dispersed in the plating bath, and the same as in Test Example 1 A composite plating film was obtained by various methods. The thickness of each layer was the same as in Test Example 1, and the particle size, eutectoid amount,
The tin alloy plating composition is shown in Table 1. Sample Nos. 5 and 6 are examples of the present invention, and sample Nos. 7 and 8 are comparative examples.

[0012]

[Test Example 3] For comparison with the conventional example, a test piece similar to that of Test Example 1 was used and pretreated (provided with a sintered layer similar to that of Test Example 1), and contained no inorganic particles. Electrolysis was performed using a tin alloy plating bath to obtain a surface layer having the composition shown in Table 1. The thickness of each layer is the same as in Test Example 1.

[0013]

[Test Example 4] A bearing aluminum alloy (Al-6Sn-1Cu-1Ni) thin plate was roll-bonded to a steel back metal plate through a 0.1 mm bonding alloy layer (Al-5Mn) by a roll rolling method. Then, annealing was performed at a temperature of 350 ° C. for 4 hours to manufacture a bimetal. Next, the obtained bimetal was cut and machined similarly to the case of Test Example 1 to prepare a test piece. After that, after performing normal alkali etching, pickling, and zinc substitution treatment in sequence, cyan C
Electrolysis was performed in a u-Zn alloy plating bath under conditions of a bath temperature of 50 ° C. and a cathode current density of 1.5 A / dm ² , and a thickness of 2.0.
A μm Cu-5Zn intermediate layer was applied. Then, in the same manner as in Test Example 1, using SiC having an average particle size of 0.8 μm, 0.5 to 150 g / l thereof was dispersed in the plating bath to obtain a composite plating film. The amount of SiC dispersed in the plating bath was as follows for sample Nos. 12, 13, 14, and 15. No. 12: 0.5-10 g /
1, No. 13: 5-20 g / l, No. 14: 15-50
g / l, No. 15: 100-150 g / l. The thickness of each layer is 20 μm for the composite plating film and 0.
The thickness is 3 mm and the steel back metal layer is 1.2 mm. Table 1 shows the amount of co-precipitation and the tin alloy plating composition. See Sample Nos. 13 to 15 and Sample No. 12 is a comparative example. In this embodiment, the Al alloy is used as the joining alloy layer, but Ni, Ni alloy, or pure Al may be used.

[0014]

[Test Example 5] A test piece similar to Test Example 4 was used and the same test piece was used.
Pre-treated cyanide applied on normal Al alloys
Using a silver strike plating bath, bath temperature 25 ℃, cathode current density
Degree 1.5A / dm²Electrolysis under the following conditions to obtain a thickness of 5 μm
25 to 35 g / l tin and 1.5 to 15 zinc
3 g / l, caustic soda 10-15 g / l, potassium cyanide
Inorganic particles in a bath containing 20 to 25 g / l
Si₃N_Four20-150 g / l, dispersed in the plating bath
Bath temperature 65 ° C, cathode current density 2-3 A / dm ²Article
Depending on the conditions, electrolysis is performed₃N_FourEutectoid
Then, the composite plating film was obtained. In addition, SiC
The amount of dispersion in the bath is as follows for sample Nos. 16 and 17.
It became like. No. 16:30 to 100 g / l, No.
17: 100-200 g / l. Furthermore, metasulfonic acid
After plating In with an indium bath, at 100 ° C
Diffusion treatment was performed for 3 hours to obtain a composite plating film. Of each layer
The thickness is 20μm of composite plating film, aluminum alloy layer
The thickness is 0.3 mm and the steel back metal layer is 1.2 mm. Tin alloy plating
The composition is shown in Table 1. Sample No. 16 is an example of the present invention, Sample No.
17 is a comparative example.

[0015]

[Test Example 6] Table 1 collectively shows composite plating films obtained by dispersing various inorganic particles in a plating bath in the same manner as in Test Examples 1 to 5 above. Sample No. 18-20
reference. Furthermore, in order to confirm the effect of each sample, a fatigue test was carried out by a rotary load high speed bearing tester. The test conditions are shown in Table 2, and the results are shown together in FIG.

[0016]

[Table 1] A: Inventive example, BF: Comparative example

[0017]

[Table 2]

[0018]

As can be seen from the test results of each sample shown in Table 1 in FIG. 8, the average particle size of the inorganic particles is 1.5 μm.
The product of the present invention has the following main functions as a sliding bearing overlay, in which the total content in the composite plating film is 0.05 to 5% by volume, and the Vickers hardness of the composite plating film is Hv5 to 30. Since it retains a certain familiarity, fatigue resistance is not increased, and improvement in wear resistance is recognized due to the effect of the inorganic particles present in the overlay. When the average particle size of the inorganic particles exceeds 1.5 μm and the amount of the inorganic particles co-precipitated is 5% by volume or more, the overlay hardness exceeds Vickers hardness of 30, and therefore the conformability and toughness are improved. It can be seen that the overlay becomes lacking and overlay fatigue occurs due to continuous pressure fluctuations, resulting in an extremely large amount of wear. In addition, in the case where the ratio of the inorganic particles in the composite plating film is 0.05% or less, and in the case where the inorganic particles are not included, the overlay itself does not fatigue, but the abrasion resistance is higher than that of the present invention product. It turns out that is inferior. From the above, it is understood that the product of the present invention is a composite plated slide bearing having improved wear resistance without impairing fatigue resistance.

[Brief description of drawings]

FIG. 1 is a plan view of a plain bearing.

FIG. 2 is a cross-sectional view of a copper alloy layer having a copper alloy layer according to an embodiment of the present invention.
Layered plain bearing.

FIG. 3 shows a three-layer structure sliding bearing according to one embodiment of the present invention.

FIG. 4 is a diagram showing a modification of the sliding bearing shown in FIG.

FIG. 5 is a sectional view of an essential part of a two-layer structure slide bearing having an aluminum alloy layer according to an embodiment of the present invention.

FIG. 6 is a view showing a modification of the sliding bearing shown in FIG.

FIG. 7 is a cross-sectional view of a main part of a 5-layer structure sliding bearing according to the present invention and an example in which an aluminum alloy layer is provided on a steel back metal.

FIG. 8 is a bar graph showing the results of the Soda fatigue test.

[Explanation of symbols]

 1 Sn or Sn-based alloy layer 2 Intermediate plating layer 3 Cu bearing alloy layer 4 Back metal layer 5 Al bearing alloy layer 6 Bonding layer

Front Page Continuation (72) Inventor Hirofumi Michioka 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Yoshio Fuwa 1, Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd.

Claims (7)

[Claims] 1. A slide bearing having a tin or tin-based alloy composite plating film on the surface thereof, containing co-precipitated inorganic particles, wherein the inorganic particles dispersed in tin or tin-based alloy have an average particle size of 1 The sliding bearing having a composite plating film having a Vickers hardness of Hv5 to 30 and having a Vickers hardness of Hv5 to 30. . 2. The tin-based alloy is Cu, Sb, Zn, In
The sliding bearing having the composite plating film according to claim 1, wherein the sliding bearing has one or more elements selected from the following, and the balance is substantially Sn except for unavoidable impurities. 3. The tin-based alloy is Cu, Sb, Zn, In
One or two or more elements selected from the total of 0.
The sliding bearing having the composite plating film according to claim 2, wherein the sliding bearing contains 1 to 25% by weight. 4. A laminated body comprising a steel back metal plate, a bearing alloy layer provided on the back metal plate, and a composite plating film provided on the bearing alloy layer. A plain bearing having the composite plating film as described in any one of 1 above. 5. The bearing alloy forming the bearing alloy layer,
A bearing copper alloy or a bearing aluminum alloy.
A slide bearing having the composite plating film described in 1. 6. A thickness of 0.5-5 μm between the composite plating film and the bearing alloy layer which is a lower layer of the composite plating film.
m intermediate plating layer exists, and the intermediate plating layer is
Ni, Ni alloy, Co, Co alloy, Fe, Fe alloy, C
A slide bearing having a composite plating film according to claim 4 or 5, which is formed of any one metal selected from the group consisting of u, Cu alloy, Ag, Ag alloy, Zn, and Zn alloy. . 7. Between the back metal plate and the bearing alloy layer,
There is a bonding metal layer for strengthening the bonding of both layers, and the bonding metal layer is any one selected from the group consisting of Ni, Ni alloy, Cu, Cu alloy, Al and Al alloy.
A slide bearing having the composite plating film according to any one of claims 4 to 6, which is formed of one kind of metal.