JP2992100B2 - Plain bearing - Google Patents

Abstract

PURPOSE:To prevent seizing caused by corrosion and fatigue originated in an intermediate layer at the time of subjecting the surface layer of an aluminum allay series lining to Pb series overlaying. CONSTITUTION:On the surface of an aluminum alloy bearing, (1) 0.01 to 2mum Zn plating layer is formed, on which, as an intermediate layer, 0.1 to 5mum Sn plating layer or Sn alloy plating layer is formed, (2) on the Al-Zn diffusion layer, as an intermediate layer, an Sn plating layer or an Sn alloy plating layer is formed or (3) between the Al-Zn diffusion layer and the intermediate layer, an Sn-Zn diffusion layer is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding bearing, and more particularly, to an improvement in seizure resistance, corrosion resistance and fatigue resistance of a layer formed on an aluminum alloy bearing called a lining. The present invention relates to a sliding bearing.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 56-3316 discloses a conventional sliding bearing in which an Sn plating layer is formed on the surface of an aluminum alloy bearing and an overlay is formed thereon.

Japanese Patent Application Laid-Open No. S59-147118 discloses a method in which a Zn plating layer and a Cu-Sn plating layer are formed as an intermediate layer on the surface of an aluminum alloy bearing, and a P layer is formed on the intermediate layer.
A plain bearing with a b-Sn overlay is described.

[0004]

SUMMARY OF THE INVENTION The above-mentioned JP-A-56-33
According to Japanese Patent No. 16, since the adhesion between Al and pure Sn of the lining is low, the overlay of the surface layer is liable to peel and wear,
It is difficult for the overlay effect to be sufficiently exhibited.

In the plain bearing disclosed in Japanese Patent Application Laid-Open No. Sho 59-147118, the wear of the overlay progresses, and the Cu-Sn alloy having poor seizure resistance is exposed when the intermediate layer is exposed. Happens. Also, if the overlay is P
Since the corrosion resistance is poor due to the b-system, corrosion wear is apt to occur, and the overlay surface becomes a rough surface irrelevant to the roughness of the mating shaft, resulting in seizure. Further, under a condition in which the load applied to the slide bearing is high, the surface pressure is high, or the peripheral speed is high, the hard and brittle intermediate layer made of a Cu—Sn alloy is easily peeled and easily fatigued.

Accordingly, an object of the present invention is to prevent seizure due to corrosion and fatigue by improving the intermediate layer when a Pb-based overlay is applied to the surface layer of an aluminum alloy-based lining.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, a first aspect of the present invention is to provide an aluminum alloy bearing surface with Z
An n-plated layer is formed in a thickness of 0.01 to 2 μm, and a Sn-plated layer or a Sn alloy-plated layer is formed thereon as an intermediate layer.
Provided is a plain bearing having a thickness of 1 to 5 μm and a Pb-based overlay formed on the outermost surface.

The sliding bearing according to the second aspect of the present invention comprises:
An Al—Zn diffusion layer is formed on the surface of an aluminum alloy bearing, a Sn plating layer or a Sn alloy plating layer is formed thereon as an intermediate layer, and a Pb-based overlay is formed thereon.

Further, the sliding bearing according to the third aspect of the present invention comprises:
A Sn-Zn diffusion layer is formed between the Al-Zn diffusion layer and the intermediate layer.

The configuration of the present invention will be described below. In the first aspect of the present invention, the Al lining material used as the lining includes Al-Sn-based, Al-Pb-based, Al-
Zn-based materials can be used, and one or more of 10% or less of Cu, Mg, Zn and 10% or less of Si, Cr, Mn, Zr, V, Mo,
One or more of Co, Fe, etc. or 40% or less of Sn, P
One or more of b, Bi, and In can be added. Further, for miniaturization and spheroidization of Si, Sb, Sr, etc.
In order to refine the crystal grains, each of Ti and TiB is 0.00
You may add 1 to 1%. The lining is made by casting, rolling, sintering, extruding, spraying or the like an alloy having a predetermined composition. The sliding surface side of this Al lining material has a depth of 2
Streaks can also be formed by boring with a pitch of about 6 μm and a pitch of about 100 to 600 μm.

In the first aspect of the present invention, a Zn plating layer is formed on the surface of a lining made of an aluminum alloy in order to enhance the bonding strength of the Sn or Sn alloy layer described below. This plating layer enhances the adhesive strength, and as a result, the Sn plating layer can enhance the seizure resistance when the intermediate layer is exposed. The Sn plating layer originally has good chemical corrosion resistance to corrosive substances and the like contained in engine oil, but peeling wear has occurred due to insufficient adhesive strength. However, Zn plating or the like is provided as a Sn base. This also has the effect of preventing its progress.

When the thickness of the Zn plating layer is less than 0.01 μm, the above-mentioned effects are not exhibited. On the other hand, when the thickness exceeds 2 μm, there is no particular advantage, and the bonding strength between the Sn layer and the lining decreases. . The preferred thickness of the Zn plating layer is 0.05 to 0.1 μm. The manufacturing method can be wet plating such as immersion plating or electroplating, or dry plating such as sputtering or ion plating, or a combination of wet plating and dry plating.

By providing the above-mentioned Zn plating layer as an underlayer and providing an Sn-based layer as an intermediate layer thereon, Sn characteristics as described below can be sufficiently exhibited. Seizure resistance: When the Pb-based overlay of the surface layer disappears due to corrosion, Sn of the intermediate layer is exposed, and seizure hardly occurs. Corrosion resistance: When the Pb-based overlay on the surface layer disappears due to abrasion, the progress of corrosion is suppressed by Sn in the intermediate layer. Fatigue resistance: Even if the surface layer is worn, the Sn of the intermediate layer continues to function as an overlay. Therefore, fatigue of the lining is prevented.

In the Sn plating layer, Pb,
Sn alloy plating containing at least one of In, Sb, Ag, Ni and Zn may be used. Of these elements, P
b improves bearing surface characteristics such as corrosion characteristics and lipophilicity, and
In the following, Zn, S is hardly degraded in other properties.
b, Ag, and Ni improve the surface properties of the bearing, and when they are 5% or less, they hardly deteriorate other properties. Therefore, these components can be contained in the Sn plating depending on the use of the plain bearing.

The thickness of the pure Sn layer and the Sn—Zn, Pb, In-based alloy layer is 0.1 to 5 μm. When the thickness of this layer is 0.1 μm or less, the corrosion resistance deteriorates. When the thickness is 5 μm or more, when the Pb-based overlay layer is thin, the Sn (Sn)
Alloy) layer and diffused into the low melting point alloy Sn-Pb (solder)
Is formed. This pure Sn layer and Sn-Zn, P
The preferred thickness of the b, In-based alloy layer is 0.1 to 2 μm. The manufacturing method can be wet plating such as immersion plating or electroplating, or dry plating such as sputtering or ion plating, or a combination of wet plating and dry plating.

As the overlay layer, pure Pb having excellent conformability is used, and if necessary, as long as excellent conformability is not impaired, Sn of 20% or less for improving corrosion resistance and 15% or less in total for improving strength. Cu, Sb, Mn, Bi,
One or more of Ni, Ag, and Al, and one or more of 20% or less of In (improved corrosion resistance) can be added. The thickness of this overlay layer is preferably in the range of 1 to 20 μm. The manufacturing method can be wet plating such as immersion plating or electroplating, or dry plating such as sputtering or ion plating, or a combination of wet plating and dry plating.

Al-Z formed in the second aspect of the present invention
The n diffusion layer is formed by diffusion between Al of the first lining and Zn plating or Zn substitution plating. This diffusion further enhances the adhesive strength of the Sn (alloy) plating, and further enhances the characteristics of the Sn (alloy) plating. The thickness of the Al—Zn diffusion layer is 0.01 μm
In the following, the effect is not obtained. When the thickness exceeds 100 μm, the Zn concentration is relatively reduced and the effect is reduced.

A third feature of the present invention is that a Sn—Zn diffusion layer is formed between an Al—Zn diffusion layer and an intermediate layer (Sn or Sn alloy plating layer). Zn of the Sn—Zn diffusion layer is derived from Zn of Zn plating or Zn substitution plating, and Sn is derived from Sn of Sn (Sn alloy).

The Sn—Zn diffusion layer is formed between the Al—Zn diffusion layer and the Sn (Sn alloy plating) layer. Therefore, Zn is diffused through the Zn layer to the Sn (alloy) layer where the peak of the Zn concentration is recognized to form the Sn-Zn diffusion layer. In this case, Zn may diffuse to the outermost surface of the Sn (alloy) layer.

The Sn—Zn diffusion layer has a lining and a P
The adhesive strength between the b-based overlay and the Sn (alloy) layer is further increased, and the characteristics of the Pb-based overlay and the Sn (alloy) layer are further exhibited.

The layer structure according to the first and second aspects of the present invention is manufactured by manufacturing the sliding bearing according to the first aspect and then subjecting it to heat treatment to form an Al—Zn diffusion layer and a Zn—Sn diffusion layer. . A preferred heat treatment temperature is 50 to 180 ° C., and a preferred heat treatment time is 10 to 180 minutes.

[0022]

As described above, the Zn—Sn—Pb based overlay layer structure, the Al—Zn diffusion layer—Zn—Sn—Pb based overlay layer structure, the Al—Zn diffusion layer—Zn—Sn—Zn diffusion layer—Pb based With the overlay layer structure, a combination having excellent sliding characteristics as a coating layer of the aluminum alloy lining can be provided.

When the overlay layer structure is applied to a plain bearing for an engine crankshaft or the like after the Al lining is formed with a groove, the Al lining-Zn layer-Sn・ Sn
Alloy layer-Pb alloy layer, Al-based lining-Al-Zn diffusion layer-Sn-Sn alloy layer-Pb alloy layer, or Al
System Lining-Al-Zn Diffusion Layer-Sn-Zn Diffusion Layer-
Each layer of the Pb alloy layer is mixedly exposed on the sliding surface, and the sliding characteristics are further improved. Hereinafter, the present invention will be described in detail with reference to examples.

[0024]

EXAMPLE 1 In this example, a plain bearing was constituted by the following. Overlay: composition and thickness shown in Table 1 Intermediate layer: composition and thickness shown in Table 1 Zn layer: thickness shown in Table 1 Al lining: Al-12% Sn-1.5% Pb 2.5% Si- 1% Cu-0.2% Cr Back metal: SPCC

The manufacturing steps were as follows. After the above lining was pressed against the back metal to form a bearing, alkali degreasing, smut removal treatment, Zn substitution treatment, Sn plating, and overlay formation were performed. The alkaline degreasing conditions were N
aOH-50 ° C, 60 sec, smut treatment in chromic sulfate solution at room temperature for 3 minutes, zincate treatment condition: immersion in treatment bath (27 ° C) for 60 sec, Sn
The plating was performed in an organic carboxylic acid Sn bath (30 ° C.) for 2 minutes, and the overlay forming conditions were electroplating in a solder plating bath (Pb-Sn borofluoride) at 27 ° C. for 10 minutes.

The above sample No. For 4, 6, and 9, heat treatment was performed at 155 ° C. for 10 minutes. A seizure test was carried out under the following conditions using the obtained slide bearing as a test piece. 1 to 13 in the table are comparative examples. Tables 1 and 2 show the test results obtained by cutting the oil and measuring the baking time. Further, a fatigue test was performed under the following conditions using the obtained sliding bearing as a test piece. The test results are shown in Tables 1 and 2.

[0027]

[Table 1]

[0028]

[Table 2] Remarks: No. 11 to 13 are comparative examples.

The test piece 11 is disclosed in the above-mentioned JP-A-59-14711.
And has good fatigue resistance,
The seizure was inferior, and the test piece 12 was prepared as described in JP-A-56-3316.
And has good seizure resistance but poor fatigue resistance. The test piece 13 has been subjected to ordinary Ni plating, and has poor seizure resistance. On the other hand, the test piece of the present invention has good fatigue resistance and seizure resistance.

[0030]

As described above, the present invention has excellent corrosion resistance, fatigue resistance and seizure resistance as an intermediate layer of a sliding bearing having an aluminum alloy lining provided with a Pb-based overlay having excellent conformability. Since a combination of materials is used, it exhibits extremely excellent properties as a sliding bearing in which severe conditions are imposed on these properties.

Claims (3)

(57) [Claims] 1. A Zn plating layer having a thickness of 0.01 to 2 μm is formed on the surface of an aluminum alloy bearing, and a Sn plating layer or Pb, I having a total amount of 5% or less as an intermediate layer is further formed thereon.
containing at least one of n, Sb, Ag, Ni and Zn,
The Sn alloy plating layer whose portion is substantially made of Sn has a thickness of 0.
A plain bearing formed to have a thickness of 1 to 5 μm and a Pb-based overlay formed thereon. 2. A plain bearing having an Al-Zn diffusion layer formed on the surface of an aluminum alloy bearing, an Sn plating layer or an Sn alloy plating layer formed thereon as an intermediate layer, and a Pb-based overlay formed thereon. 3. The sliding bearing according to claim 2, wherein a Sn—Zn diffusion layer is formed between said Al—Zn diffusion layer and said intermediate layer.