JP2002310158A - Multiple layered slide material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the decrease of copper of the surface layer part of an overlay layer formed of a tin group alloy for a long period even when an intermediate layer is not thickened, in a multiple layered slide material where a tin-copper tin group overlay layer is formed on a bearing alloy layer through an intermediate layer. SOLUTION: A tin group overlay layer 6 is composed of a lower layer 4 and an upper layer 5 which are different in content amount of copper. The lower layer 4 contains a large quantity, such as, 5-20 mass% copper and its thickness is 1-3 μm. Since this constitution effects diffusion of copper from the tin group overlay layer to an intermediate layer from the lower layer 4, the decrease amount of copper of the upper layer 5 making contact with a mating material is small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-layer sliding material comprising a tin-copper tin-based overlay layer provided on a copper-based or aluminum-based bearing alloy layer via an intermediate layer.

[0002]

2. Description of the Related Art In the fields of automobiles, agricultural machines and industrial machines, plain bearings having a copper or aluminum bearing alloy on a steel backing are often used. In this plain bearing using copper or aluminum bearing alloy,
In order to improve conformability and foreign matter embedding property, an overlay layer is provided on the surface of a bearing alloy layer.

[0003] As the overlay layer, a lead-based alloy has been conventionally known, but recently, a tin-based alloy is often used in view of global environmental problems and improvement of corrosion resistance.
In the plain bearing provided with the tin-based overlay layer, for example, a nickel plating layer is formed as an intermediate layer between the bearing alloy layer and the overlay layer. The nickel plating layer is
When the bearing alloy is aluminum, it is provided to enhance the adhesion of the tin-based overlay layer, and when it is copper, it is provided to prevent tin in the tin-based overlay layer from diffusing into the bearing alloy. Can be

However, when the overlay layer is a tin-copper-based tin-based alloy, when used at a high temperature for a long period of time, copper in the overlay layer diffuses into the nickel plating layer due to thermal effects, and the copper in the overlay layer is diffused into the nickel plating layer. Of copper, and fatigue resistance and non-seizure properties decrease. To prevent the copper in the overlay layer from diffusing into the nickel plating layer, see Japanese Patent Application Laid-Open No. 2000-642000.
No. 085, the intermediate layer comprises a nickel layer having a thickness of 1 to 3 μm and a nickel layer having a thickness of 2 to 10 μm deposited thereon.
It is disclosed to be constituted by a tin layer.

[0005]

[Problems to be Solved by the Invention] JP-A-2000-640
In the configuration disclosed in No. 85, among the intermediate layers, the lower nickel layer is hard, and the upper nickel-tin layer is harder. Then, when the overlay layer is worn by use for a considerable period of time, the hard nickel-tin layer or nickel layer is exposed on the surface. These nickel-tin layers and nickel layers are considerably thick, having a total thickness of 3 to 13 μm, and are hard and hard to wear, so that they have poor conformability and may cause seizure.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tin-based overlay layer without increasing the thickness of an intermediate layer formed between a tin-based overlay layer and a bearing alloy. It is an object of the present invention to provide a multi-layer sliding material capable of minimizing a decrease in copper in the surface layer due to diffusion.

[0007]

The present invention provides a multi-layer sliding material comprising a tin-copper tin-based overlay layer provided on a bearing alloy layer with an intermediate layer interposed therebetween, wherein the tin-based overlay layer is made of copper. Consists of multiple layers with different contents, and among the multiple layers,
The lowermost layer in contact with the intermediate layer contains 5 to 20% by mass of copper and has a thickness of 0.5 to 3 μm (claim 1).

[0008] The bearing alloy layer may be a copper-based alloy or an aluminum-based alloy. A copper-based or aluminum-based bearing alloy exhibits excellent bearing characteristics with respect to high load and high-speed rotation, and is suitable as a sliding bearing for an engine such as an automobile, an agricultural machine, and an industrial machine. As the copper-based alloy, both bronze-based and lead-bronze-based alloys can be used. As the aluminum-based alloy, an alloy containing at least one of zinc, tin, and lead for forming a soft phase can be used. Copper, magnesium, and the like as strengthening elements, chromium, silicon, and the like for improving fatigue strength can be used. Can also be contained.

[0009] Between the copper-based or aluminum-based bearing alloy layer and the tin-copper-based tin-based overlay layer as described above,
An intermediate layer is provided to prevent tin in the tin-based overlay layer from diffusing into the bearing alloy layer or to improve the adhesion of the tin-based overlay layer to the bearing alloy layer. This intermediate layer can be composed of any of nickel, iron and cobalt. Its thickness is 0.5-3
It is preferably μm (claim 4). When the sliding material is used at high temperatures, the copper in the tin-based overlay layer diffuses into the intermediate layer. According to the present invention, the lower layer of the tin-based overlay layer has a relatively high copper content, so that diffusion of copper from the tin-based overlay layer to the intermediate layer proceeds from the bottom layer of the tin-based overlay layer. For this reason, the reduction of copper is small in the uppermost layer of the tin-based overlay layer in contact with the counterpart material. Therefore, the thickness of the intermediate layer does not need to be so large, and even when the tin-based overlay layer is exposed to the intermediate layer due to abrasion, the conformability is not lost and excellent anti-seizure property is obtained. maintain.

The uppermost layer of the tin-based overlay layer preferably has a copper content of 0.5 to 10% by mass. One or more of zinc, indium, antimony, and silver can be contained in the uppermost layer of the tin-based overlay layer in a total amount of 5% by mass or less (claim 3). Here, the reason for setting the component ratio as described above will be described. (1) Copper in the lowermost layer of the tin-based overlay layer: 5 to 20% by mass When the amount of copper is less than 5% by mass, the effect of preventing the diffusion of copper in the uppermost layer decreases, and when it exceeds 20% by mass, the fatigue resistance decreases. I do. The lowermost layer of the tin-based overlay layer preferably has a thickness of 1 to 3 μm. If it is less than 1 μm, the effect of preventing the diffusion of copper in the uppermost layer cannot be obtained, and if it exceeds 3 μm, the fatigue resistance decreases.

(2) Copper in the uppermost layer of the tin-based overlay layer:
0.5 to 10% by mass Tin matrix is responsible for corrosion resistance, conformability, and foreign matter embedding property, while copper increases the strength of the tin matrix and improves non-seizure, fatigue resistance, and abrasion resistance. If it is less than 0.5% by mass, the effect is low, and if it exceeds 10% by mass, non-seizure properties and fatigue resistance are reduced. The thickness of the top layer of the tin-based overlay layer is
10 to 40 μm is preferred. If it is less than 10 μm, the conformability and the foreign matter embedding property decrease, and if it exceeds 40 μm, the fatigue resistance decreases.

(3) zinc on the uppermost layer of the tin-based overlay layer;
Indium, antimony, silver: 5% by mass or less in total amount These elements improve the non-seizure property and the wear resistance of the uppermost layer of the tin-based overlay layer. If it exceeds 5% by mass, the uppermost layer becomes too hard, and the conformability and the foreign matter embedding property are reduced.

(5) Intermediate layer: any one of nickel, iron, and cobalt Nickel, iron, and cobalt prevent tin in the tin-based overlay layer from diffusing into the bearing alloy layer (in the case of a copper-based bearing alloy). Alternatively, the adhesion of the tin-based overlay layer to the bearing alloy layer is increased (in the case of an aluminum-based bearing alloy). The thickness of the intermediate layer is preferably 0.5 to 3 μm. If the thickness of the intermediate layer is less than 0.5 μm, no dam effect or adhesive strength is obtained,
If it exceeds 3 μm, the non-seizure property after the wear of the tin-based overlay is reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described by way of embodiments with reference to the drawings. Lead: 23% by mass, tin:
A bimetal as a bearing material was manufactured by sintering and rolling a copper-based bearing alloy powder composed of 3.5% by mass and the remaining copper. The bimetal was press-molded to form a half bearing with a thickness of 1.5 mm, and the half bearing was machined to a predetermined size. Thereafter, a nickel layer having a thickness of 1.5 μm was formed on the inner surface of the half bearing by electroplating, and a tin-based alloy having a component shown in the lower layer of Table 1 was electroplated thereon, except for Comparative Examples 1 to 4. Then, a tin-based alloy having the components shown in the upper layer of Table 1 was electroplated on the lower layer. With respect to Comparative Examples 1 to 4, only one layer of the tin-based alloy having the components shown in the upper layer of Table 1 was electroplated on the nickel layer to a thickness of 15 μm.

As described above, as shown in FIG. 1, a copper-based bearing alloy layer 2 is formed on a steel backing metal layer 1, an intermediate layer 3 made of a nickel plating layer is formed on the bearing alloy layer 2, and
Example products 1 to 10 and comparative products 5 to 7 having a structure in which a tin-based overlay layer 6 composed of two layers of a lower layer 4 and an upper layer 5 having different copper contents were provided on the intermediate layer 3 were obtained. Although not shown, a comparative example of a structure in which a copper-based bearing alloy layer is formed on a steel backing metal and a single tin-based overlay layer is provided on the bearing alloy layer via an intermediate layer formed of a nickel plating layer. Articles 1-4 were obtained.

[0016]

[Table 1]

Examples 1 to 10 and Comparative Example 1
7 were subjected to a thermal diffusion test, a seizure test, and a fatigue test. In the thermal diffusion test, the state heated to 130 ° C. was 300
The content of copper in the upper layer of the tin-based overlay layer was examined after holding for a period of time and after holding for 1000 hours.

The baking test was performed on a VG22 preheated to 100 ° C.
3600 rpm by motor using lubricating oil
m, and a running operation with no load for 1 hour. After that, the lubricating oil was squeezed to 150 cc per minute to apply a load of surface pressure of 10 MPa. Then, while increasing the surface pressure by 5 MPa,
The bearing was operated for 10 minutes at each contact pressure, and when the back surface of the bearing exceeded 200 ° C. or the drive current of the motor driving the mating member exceeded a predetermined value, the bearing contact pressure at that point was defined as the seizure contact pressure. . This baking test was performed twice for each of the cases where the above-mentioned thermal diffusion was not performed and the case where the thermal diffusion was performed at 130 ° C. for 1000 hours.

In the fatigue test, SAE2 preheated to 100 ° C.
Using a lubricating oil of 0, the mating material was rotated at 3250 rpm, and a running-in operation without load was performed for 30 minutes.
The degree of fatigue when operating for 20 hours under a load of 0 MPa was evaluated. Evaluation is shown by the following five fatigue evaluation ranks. Similar to the seizure test, this fatigue test was performed twice for each of those that did not perform thermal diffusion and those that performed thermal diffusion at 130 ° C. for 1000 hours. 5: No crack. 4: In the evaluation 4, cracks could not be visually confirmed and microscopic inspection could be confirmed. 3: Cracks can be visually confirmed, but hard to recognize. 2: Cracks can be visually observed. 1: Cracks of 50% or more of the projected area of the bearing can be visually confirmed.

Regarding the above-mentioned thermal diffusion test, Example product 1,
The results for 3, 9, 10 and Comparative Examples 2, 3, 5 are shown graphically in FIG. The results of the seizure test and the fatigue test are shown in FIGS. 3 and 4, respectively. In FIGS. 3 and 4, white outlines indicate the results of two tests.

As apparent from FIGS. 2 to 4, Examples 1 to 10 in which the tin-based overlay layer is made of two upper and lower layers and the copper content of the lower layer is 5 to 20% by mass, the comparative example without the lower layer is provided. As compared with Examples 1 to 4, the amount of decrease in the surface portion of the tin-based overlay layer due to thermal diffusion of copper is small. Therefore, Examples 1 to 10 show excellent non-seizure and fatigue resistance even after a heat diffusion test at 130 ° C. for 1000 hours.

In Comparative Examples 5 to 7, the tin-based overlay layer is composed of two upper and lower layers. However, Comparative Example Product 7 has low fatigue resistance because the copper content before the thermal diffusion test in the lower layer of the tin-based overlay layer is as large as 23.5% by mass. If the copper content of the lower layer of the tin-based overlay layer is small, the effect of preventing copper from diffusing into the upper layer is reduced, and if it is large, the fatigue resistance is adversely affected. The preferred copper content of the lower layer of the tin-based overlay layer is 5 to 20% by mass.

In Comparative Example 5, the thickness of the lower layer of the tin-based overlay layer is as thin as 0.5 μm. For this reason, the copper diffusion preventing effect on the upper layer is low, and the upper layer copper is initially 4.1% by mass.
However, after 300 hours of the thermal diffusion test, 2.1
After 1000 hours, the content is greatly reduced to 0.9% by mass. As a result, the non-seizure property and the fatigue resistance are reduced after 1000 hours of the thermal diffusion test. On the other hand, the comparative example product 6 is inferior in fatigue resistance even before the thermal diffusion test because the thickness of the lower layer of the tin-based overlay layer is as large as 5 μm. From this, it is understood that when the thickness of the lower layer of the tin-based overlay layer is thin, the effect of preventing copper from diffusing into the upper layer is reduced, and when the thickness is thick, the fatigue resistance is reduced. The preferred thickness of the lower layer of the tin-based overlay layer is 1
３3 μm.

As described above, the tin-based overlay layer is divided into upper and lower two layers, and the lower layer has a copper content of 5 to 20% by mass and a thickness of 1 to 3%.
When the thickness is set to μm, the reduction of copper in the upper layer can be suppressed, so that the thickness of the nickel plating layer as the intermediate layer can be reduced (1.5 μm in Examples 1 to 10). For this reason, when the overlay layer is worn and the intermediate layer is exposed on the surface, the intermediate layer wears relatively quickly, and the chance of seizure due to the contact of the mating material with the intermediate layer made of hard nickel is reduced. can do.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be extended or modified as follows. The intermediate layer is not limited to nickel, and may be nickel, iron, or cobalt. The copper content of the upper layer 5 of the tin-based overlay layer 6 may be higher than that of the lower layer 4. The tin-based overlay layer 6 is not limited to two layers, but may be three or more layers. In this case, it is preferable to reduce the copper content from the lowermost layer toward the uppermost layer.
If it is at 0% by mass, the copper content of the layer above it may be higher or lower than that of the lowermost layer. The uppermost layer of the tin-based overlay layer may contain 5% by mass or less of inorganic particles for improving abrasion resistance.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a graph showing the results of a thermal diffusion test.

FIG. 3 is a graph showing the results of a seizure test.

FIG. 4 is a graph showing the results of a fatigue test.

[Explanation of symbols]

1 is a steel backing metal layer, 2 is a copper-based bearing alloy layer, 3 is an intermediate layer, 4 is a lower layer, 5 is an upper layer, and 6 is a tin-based overlay layer.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takayuki Shibayama 2 Sanage-cho, Kita-ku, Nagoya-shi F-term (reference) in Daido Metal Industry Co., Ltd. 3J011 AA08 CA05 DA01 LA04 MA02 QA03 SB03 SB05 4K024 AA03 AA21 AB03 BA09 BB05 BC07 GA03

Claims (5)

[Claims] 1. A multilayer sliding material comprising a tin-copper tin-based overlay layer provided on a bearing alloy layer via an intermediate layer, wherein the tin-based overlay layer comprises a plurality of layers having different copper contents. Wherein the lowermost layer of the plurality of layers, which is in contact with the intermediate layer, contains 5 to 20% by mass of copper and has a thickness of 1 to 3 μm. 2. The multi-layer sliding material according to claim 1, wherein the uppermost layer of the tin-based overlay layer has a copper content of 0.5 to 10% by mass. 3. An uppermost layer of the tin-based overlay layer includes at least one of zinc, indium, antimony, and silver.
3. The multi-layer sliding material according to claim 1, wherein a total of 5% by mass or less of at least one kind is contained. 4. The intermediate layer is made of any one of nickel, iron and cobalt, and has a thickness of 0.5 to 3 μm.
The multilayer sliding material according to any one of claims 1 to 3, wherein m is m. 5. The multi-layer sliding material according to claim 1, wherein the bearing alloy layer is made of a copper alloy or an aluminum alloy.