JPS62113913A - Plain bearing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The invention relates to a multilayer plain bearing for an internal combustion engine as defined in the opening paragraph of claim 1.

(Prior Art) In large internal combustion engines, especially diesel engines in which the pressure inside the cylinders is extremely high, the mechanical stress exerted on the main bearing and the crank end bearing is extremely large. Most of the main bearings in engines currently in use are plain bearings with a layered structure. Such bearing means take advantage of the good sliding properties of bearing metals and at the same time prevent them from becoming mechanically fragile by providing them as a relatively thin surface layer.

In so-called three-component bearings, the bearing metal is arranged on a steel support shell of the bearing. The bearing metal is about 1 m thick and is made of lead bronze or light metal and has sufficient strength properties and good thermal conductivity. This intermediate layer is also called lining. At the top, a thin sliding layer or overlay of white metal is provided, and for bearings subject to heavy loads, the plating thickness of this overlay ranges from 0.02 m+ to 0.00 m.
It is between 06 shoes. Furthermore, a thin diffusion barrier or layer of connecting metal is arranged between these three material layers.

Although the bearings of this scale have good durability and thermal ffi conductivity, they do not have the ability to compensate for small scratches in the equipment or to trap dust particles into the bearing metal.

In known art sliding bearings, the top sliding layer is made of a single layer of alloy or some kind of man-made material. Overlays applied by plating must be considerably thinner, especially for reasons of strength. This has given rise to many types of problems. Among these problems is that they are easily damaged by wear and tear. If the clearance between the journal and the plain bearing is small, as the bearing heats up, the spacing may become so small that the bearing may become stuck. Such a phenomenon may occur if the bearing is not properly lubricated and the lubrication is impaired, for example if dust particles that do not fall down destroy the oil film of the bearing. Because the overlay is made of a soft material with a lower melting point than the lining,
If the bearing heats up, it is desired that the overlay be particularly thick because the bearing will become immobile due to overheating.

On the other hand, thick overlays cannot be made using known techniques since the ability to maintain surface pressure is steadily weakened by fatigue.

(Means for Solving the Problems) The object of the present invention is to provide a highly reliable layer which has better adaptability, compensation ability and dust removal ability than the conventional ones, and which does not reduce the strength characteristics of the bearing. The structure consists in producing the main bearing and the crank side end bearing. Yet another object is to create a sliding bearing in which thicker overlays than conventional bearings can be used and in which further material components of the sliding layer can be added, especially with a lower melting point and hardness.

The object of the invention is achieved by a structure according to claim 1. The basic structure of the bearing of the invention is a three-component sliding bearing, in which the bearing overlay consists of three or multiple metal or alloy layers. This configuration allows the overall thickness of the overlay to be increased without reducing its ability to maintain surface pressure. At the same time, a good conformability and dust removal ability of the sliding surface is obtained, which greatly improves the reliability of the bearing. As an effective solution, two types with different hardness and melting point
Two metals or alloys are used, and the layers of these materials are arranged alternating with each other to form the overlay of the bearing. In such a solution, the hard material layer gives the overlay the ability to maintain surface pressure due to its high yield point, while the soft material layer provides the preferred thickness of the sliding layer.

Alternatively, the different material layers of the overlay can also be composed of metals or alloys of equal hardness, provided that a high strength is obtained from the synergistic effect of different metal layers of different bond structures. It is not necessary that all the different material layers of the overlay constitute a complete covering layer; different interlayers of mesh or lattice may also be provided.

When forming the sliding layer, it is advantageous to use physical gas phase coating methods. Such well-known methods, which are not within the scope of the present invention, include, for example, certain sputter coating methods or ionization coating methods. The desired structure of the sliding layer is obtained by alternately depositing different metals or alloys. Other coating methods can also be used to form the sliding layer, for example chemical gas phase reactor methods or metal spray methods. However, with this method,
It is rather difficult to obtain the properties of the sliding layer according to the invention. For example, metal spraying has the disadvantage that the thickness of the individual material layers is often too thick and the surface is spongy.

For heavily loaded engines, the total thickness of the overlay may be 0.03 mm, preferably at least 0.05 mm. That is, the thickness of the sliding layer can be made at least three times as thick as in conventional methods while still meeting the requirements regarding strength. When the sliding bearing having the structure of the present invention is used in a small engine, the overlay is 0.01
It can be made to a thickness of about 2m5+. The overlay should consist of at least three different layers, for example two layers of soft material and a layer of hard material between these layers. Vapor deposition and sputtering methods allow the formation of very thin material layers.

It is therefore also possible to construct the lining with a very large number of layers, for example 10 or 20 alternating layers of two different materials. Instead of two different overlay materials, three or more different overlay materials may be used. In this way, it can also be configured such that, even if the top layer disappears, no hard material forms the sliding surface after this layer.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

(Example) In the figures, reference number 1 indicates a support shell made of steel. On this shell is an intermediate layer or lining 2.
is located. The intermediate layer or lining 2 is made of a lead-bronze alloy or the like, white metal or bronze and has a high load strength and good thermal conductivity. A diffusion barrier layer 3, made of nickel, for example, is provided between the intermediate layer 2 and the actual overlay 4.

The sliding surface 4 with which the invention is concerned is made of multiple layers and consists of layers A and 8 of two different metals or alloys. The material layer A is made of a metal with excellent sliding properties, low hardness, and a low melting point, such as tin-antimony. On the other hand, material aB made of aluminum-tin, for example, has high hardness and strength. By alternating these material layers A and 8 with each other, the overall thickness of the lining can be increased. Therefore, the overall thickness of the soft material layer A can be significantly increased without adversely affecting the strength characteristics of the bearing. According to a preferred embodiment shown in the figure, the soft material layer is made thicker than layer B;
Moreover, one to the soft material layer forms the uppermost sliding surface of the bearing.

The individual layers of the overlay are coated using some well-known gas phase coating method.
method). According to this coating method, the desired material layer is formed, for example, by alternating the evaporated material or material source. Further, according to this method, the content of a specific metal contained in the alloy can be changed within the same layer.

The sliding layer is covered with a thin corrosion protection layer 5.

This corrosion protection layer is preferably made from a lead- or tin-based alloy. This protective layer also serves as a running-in layer for the bearing. The protective layer disappears from the sliding surface within a relatively short operating time. This type of corrosion protection break-in layer is commonly referred to as flash.

The invention is not limited to the embodiments described above, but can be modified in any way within the scope of the claims. The number of material layers and the material thicknesses can vary, and two or more metals or alloys can be used to construct the overlay within the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a partially sectional view showing an embodiment of the present invention. FIG. 2 is a sectional view taken along line I--n in FIG. 1. 1...Support shell, 2...Middle layer (lining) 3...Diffusion barrier layer 4... Overlay, 5...corrosion protection layer, A, B...material layers.

Claims (6)

[Claims] (1) In the main bearing or crank end bearing of an internal combustion engine, for example a large diesel engine, the bearing preferably forms a sliding surface with a supporting shell (1) and with an intermediate layer or lining (2). A so-called three-component sliding bearing, consisting of a lining (4), in which the lining (4) of the sliding bearing has two or more components with different hardness properties and melting points and different crystal structures. It consists of layers (A, B) of different metals or alloys, and these layers (A
, B) are arranged alternately with each other and the overlays are at least 3
A sliding bearing characterized in that it is formed from two different materials. (2) said overlay (4) is coated with a flash layer (5), a corrosion protection and break-in layer of lead or lead-based alloys, tin or similar materials; A sliding bearing according to claim 1, characterized in that: (3) The material layer of the overlay (4) is produced by a sputtering method, a vapor deposition method or a similar physical gas phase coating method; or The sliding bearing according to item 2. (4) Some of the material layers (A, B) of the lining are not completely covered, but are formed as net-like or lattice-like layers. The sliding bearing described in any one of item 3. (5) In an engine subject to heavy loads, the overall thickness of the overlay (4) is at least 0.03 mm, preferably at least 0.05 mm. A plain bearing as described in any one of the following paragraphs. (6) The material of the overlay is a tin-antimony alloy (A) and an aluminum-tin alloy (B), according to any one of claims 1 to 5. sliding bearing.