KR101288336B1 - Bearing having embedded hard particle layer and overlay and method of manufacture - Google Patents

Abstract

The multi-layer sliding bearing includes a rigid metal backing 12 to which the metal bearing liner 14 is attached. The metal bearing liner includes a metal bearing liner layer 16 attached to the bearing face of the metal backing layer and one or more metal overplate layers deposited on the outer surface of the metal bearing liner layer. The metal bearing liner layer has a layer of hard particles 30 embedded in the outer surface of the metal bearing liner layer adjacent to the inner surface of the one or more metal overplate layers. The bearing is interposed between the metal bearing liner layer and the metal overplate layer to inhibit diffusion between the metal bearing liner layer and the metal overplate layer or to promote adhesion of the metal overplate layer to the metal bearing liner layer or both. Barrier layer 22 may also be included. The present invention may also include a thin film metal protective coating layer 28 on the outer surface of the bearing liner and backing layer. The present invention also provides a method of fabricating a metal backing layer having a bearing face, attaching a metal bearing liner having an outer face to a bearing face of a metal backing layer, embedding a layer of hard particles in an outer face of the metal bearing liner layer, And depositing one or more metal overplate layers on the outer surface of the metal bearing liner layer. The method may also include depositing a barrier layer on an outer surface of the metal bearing liner layer prior to depositing the metal overplate layer.

Metal backing, liner layer, hard particles, overplate layer, barrier layer, multilayer sliding bearing

Description

Bearing and manufacturing method having buried hard particle layer and overlay {BEARING HAVING EMBEDDED HARD PARTICLE LAYER AND OVERLAY AND METHOD OF MANUFACTURE}

BACKGROUND OF THE INVENTION Field of the Invention The present invention generally relates to sliding bearings and a method of manufacturing the same. More particularly, the present invention relates to a multilayer engine bearing of the type having a metal backing covered with a functional bearing layer and then plated with an overlay of soft metal. More specifically, the present invention optionally has a functional layer having a surface layer of hard particles embedded inside where a layer of soft metal is plated with a diffusion barrier layer between the soft metal layer and the functional bearing layer. A multilayer bearing having a bearing layer.

Sliding engine journal bearings used in heavy duty engine applications to journal crankshafts and the like typically include a lining layer having a functional bearing layer of copper-lead or aluminum alloy coated on a steel backing. A single layer of lead-tin-copper alloy with a thickness of approximately 25 μm is typically overplated onto the functional bearing layer. Often a nickel diffusion barrier layer or copper bonding layer is interposed between the overplate and the functional bearing layer to prevent tin from diffusing from the overplate into the bearing layer. As a final step, the bearing may be optionally coated with a micro-thin layer of tin or lead-tin flash plating, having a thickness of approximately 1 μm or less. Flash plating is functional and aesthetic, giving the product a protective outer layer and a shiny, aesthetically pleasing appearance. It also provides corrosion protection levels to the steel backing. In a short time during the break-in period of the engine, the flash plating coated on the running surface of the bearing is abraded by the action of the components produced by the bearing.

In use, such multi-layer crankshaft bearings are subject to high dynamic loads that change in size and direction due to inertial loads imposed by the piston and the connecting rod mechanism and by the combustion gases. The soft overlay layer allows these bearings to follow under high loads to a change or misalignment of the load profile of the journaled member, such that the load is distributed across the larger surface area of the bearing. The overplate also allows foreign particles of dust or metal to be embedded or absorbed in the bearing face, so as to protect both the bearing and the journaled component from excessive wear and damage.

The conformability and embedability of the overplate depends on the thickness of the overplate, and it is generally accepted that thicker overplates are preferred. It is also generally known that as the thickness of the overplate increases, the sensitivity to bearing fatigue (ie breakage of the bearing face when under load) increases. Resistance to fatigue cracking requires that the bearing face have sufficient tensile strength to withstand small contour changes without cracking. On the other hand, however, certain alloys that exhibit improved resistance to fatigue and strength also tend to be more seizure and more sliding wear to journaled components, such as crankshafts, during engine operation. Therefore, when designing engine bearings, especially bearings susceptible to high dynamic loads, it is necessary to balance the properties of coherence and embedding with respect to the fatigue resistance of the bearing layer.

For many high load engine applications, the 25 μm thick single layer overplate of the lead-tin-copper alloy described above has been found to provide good mating and buried properties and good fatigue resistance of typical bearing layers. However, as the power and efficiency of the engine increases, the dynamic load placed on the crankshaft bearings increases, increasing the potential for bearing fatigue. Under extreme loading conditions, the aforementioned conventional bearings employing a single overplate of 25 μm thickness of lead-tin-copper can be prone to fatigue. Efforts to mitigate fatigue by simply reducing the thickness of single layer overplates to less than 25 μm have largely failed, at the expense of satisfactory levels of coherence and embedding. As performance requirements increase, not only can they be used under these extremely high dynamic load conditions by providing a soft overlay of sufficient thickness to meet coherence and embedding, but at the same time the wear resistance and required wear of the bearing layer There is an industrial need for improved journal bearings that can use higher fatigue resistant bearing alloys that also have characteristics.

The present invention is a multi-layer bearing, such as a journal bearing with a soft overplate layer that provides coherence and embedding, wherein the multi-layer bearing is a hard particle embedded at the outer surface to provide improved wear characteristics and erosion resistance of the bearing during operation. It also has a bearing lining that includes layers of.

Multilayer bearings of the present invention, such as sliding bearings, include a metal backing layer having a bearing face. The bearing also includes a metal bearing liner layer attached to the bearing face of the metal backing layer and having a layer of hard particles embedded in the outer face thereof. The bearing also includes one or more metal overplate layers deposited on the outer surface of the metal bearing liner layer. The bearing is provided between the liner layer and the one or more metal overplate layers for the purpose of providing a diffusion barrier between the metal bearing liner layer and the one or more metal overplate layers or for promoting adhesion of the metal overplate layer to the metal bearing liner layer. It may optionally include an intervening barrier layer.

The hard particles used will have a hardness that is greater than the hardness of the metal bearing liner layer, and is preferably substantially harder than the rigidity of this metal bearing liner layer. The hard particles may be selected from the group consisting of pure metals and metal alloys, metal carbides, metal silicides, metal nitrides and metal borides having a hardness greater than the hardness of the metal bearing liner layer.

The invention also includes a method of making a multilayer sliding bearing. The method includes fabricating a metal backing layer having a bearing face. The method also includes attaching a metal bearing liner layer having an outer surface to the bearing surface of the metal backing layer. The method also includes embedding a layer of hard particles into the outer surface of the metal bearing liner layer and depositing one or more metal overplate layers on the outer surface of the metal bearing liner layer after the hard particles are embedded. The method may optionally include depositing a barrier layer on the bearing liner layer prior to depositing the metal overplate layer.

Various features and advantages of the present invention will be more readily understood by reference to the following detailed description and the accompanying drawings.

1 is a perspective view of one embodiment of a multilayer bearing of the present invention;

2 is a perspective view of a second embodiment of a multilayer bearing of the present invention;

3A is a partially enlarged cross-sectional view of one embodiment of a bearing layer and overlay of the present invention generally taken along line 3--3 of FIG.

3B is a partially enlarged cross-sectional view of a second embodiment of a bearing layer and overlay of the present invention generally taken along line 3--3 of FIG.

4 is a partially enlarged cross-sectional view taken along line 4--4 of FIG. 3A; And

5 is a partially enlarged cross-sectional view taken along line 5--5 of FIG. 3B.

Multilayer bearings constructed in accordance with the invention are shown generally at 10 in FIG. 1, with a pair therebetween to form a journaled connection between two relatively rotatable components, such as a connecting rod and a crankshaft. It consists of a sliding type, often referred to as a journal bearing or a sliding bearing of the type used. Such multilayer bearings of the type according to the invention also comprise a multilayer bushing.

1, 3A and 4, a bearing 10 constructed in accordance with the present invention is a multilayer metal bearing material formed on a backing that collectively forms the rigid metal support backing 12 and the foundation of the bearing 10. It includes a multi-layer bearing liner 14 including. The bearing liner 14 includes a bearing lining layer 16 which is the main bearing material of the bearing 10. The backing preferably comprises an arcuate semicircular steel strip having a convex outer surface 18 adapted to rest on the contacting concave support structure and an opposing concave inner surface 20 that is a bearing surface on which the bearing liner 14 is coated. have.

The bearing lining layer 16 may be formed of a conventional bearing layer material composed of an alloy comprising a conventional combination of copper-lead or aluminum, and sintered, cast, coated on the inner surface 20 in accordance with known practice. cladding) or otherwise formed or adhered to the inner surface. In accordance with the present invention, it is expected that new hard alloys such as CuSn ₈ Ni may be used as the bearing lining layer 16 in the bearing liner 14. Such alloys would not normally be used in bearings of conventional construction because of the possibility of bearing failure due to the seizure of the bearings to the journaled components.

The bearing liner 14 is nickel or copper, i.e. a diffusion barrier between the component materials of the bearing liner layer 16 and the overplate layer 24 and / or a thin film barrier of other materials effective as an adhesion promoter, i. Layer, ie, film 22 (ie, approximately 1-2 μm thick). The barrier layer 22 may be electroplated or otherwise deposited on the bearing liner 14 and bearing lining layer 16 according to conventional practice.

The bearing liner 14 also includes an overlay, ie an overplate layer 24. The overplate layer 24 may be formed of a single layer of pure metal or alloy from conventional overplate materials and, as with PbSnCu, PbSn or PbIn alloys, is generally soft, ductile and conformable and embedding described herein. to provide. The overlay or overplate layer 24 may be plated or otherwise deposited on the bearing liner 14 and the bearing lining layer 16, such as electroplating or non-electrode plating, according to conventional practice. Alternatively, overplate layer 24 may be described in US Pat. No. 6,077,815; 6,086,742; 6,178,639 B1; 6,277,709 B1; 6,312,579 B1; Multi-layer overplate layers 24 formed by the methods disclosed in 6,337,145 B1 and 6,609,830 B2, the entire contents of which are incorporated herein by reference. The embodiment shown in FIG. 1 is an embodiment according to the invention using a bearing without a thrust flange (ie, a smooth bearing). With reference to FIG. 2, the present invention can be used for bearings of similar construction (ie flange bearings) with thrust flanges 26.

The bearing liner 14 may include a thin film metal protective layer 28, such as a thin film layer of tin, to protect the bearing liner 14 and / or backing layer 12.

In one example of a multilayer structure, the overplate 24 comprises two or more layers plated in the same plating bath at different current densities, outer and inner layers for the bearing lining layer 16. The outer layer may be plated at a relatively high current density to yield a relatively soft overplate layer having a thickness of approximately 3-7 μm, preferably approximately 5 μm, to provide good matchability and embedding of the overplate. Can be. The inner layer has a relatively low current to yield a layer that is relatively harder than the outer layer, having a thickness ranging from approximately 7 to 13 μm, preferably 10 μm thick, to provide support backing to the outer layer for good fatigue strength properties of the overplate. It can be plated in density. It will be appreciated that the example of the particular two layers described is only one of numerous variations that may be employed and envisioned by the present invention. The outer and inner layers can be reversed, for example, so that the outer layers are harder than the inner layers or their thicknesses are changed to meet the needs of a particular application. Among all anticipated variants, a common property is that multilayer overplate layers are produced in the same electroplating bath and plated with different current densities to yield a synthetic lamella structure with two or more layers of different deposit properties, such as hardness.

1, 3B and 5, a second embodiment of a bearing 10 constructed in accordance with the present invention is illustrated. The same reference numerals are used for those of the above-described embodiment. This embodiment includes a rigid metal support backing 12 that collectively forms the foundation of the bearing 10 and a bearing liner 14 of metal bearing material formed on the backing. The bearing liner 14 includes a bearing lining layer 16 which is the main bearing material of the bearing 10. The backing 12 preferably comprises an arcuate semicircular steel strip having a convex outer surface 18 adapted to rest on contacting concave support structures, and an opposing concave inner surface 20 on which a bearing liner 14 is coated. Doing. This embodiment does not include a diffusion barrier.

As described above, the overplate layer 24 may be formed of a single layer of pure metal or alloy from conventional overplate materials and may be generally soft, flexible and described herein, such as PbSnCu, PbSn or PbIn alloys. Provides consistency and embedding. The overlay layer 24 may be plated or otherwise deposited on the bearing liner 14 and bearing lining layer 16, such as electroplating or non-electrode plating, according to conventional practice. Alternatively, the overplate layer 24 may comprise multiple overplate layers.

The configuration described above with respect to the bearing lining 14, which includes the bearing lining layer 16, the barrier layer 22 and the overplate layer 24, is conventional. The present invention deviates from the conventional practice in that the hard particles 32 after manufacture of the bearing lining layer 16 and before covering the overplate layer 24 or the barrier layer 22 on the lining layer 16. Layer 30 is embedded in a portion of the bearing lining layer 16 proximate the outer surface 36 of the bearing lining layer 16. Hard particles 32 may be any suitable hard particles 32, such as various pure metals, metal alloys, semi-metals, intermetallic compounds, metal oxides, metal nitrides, metal carbides, and mixtures thereof. Can be. When metal or metal alloy particles are used, the particles will be harder and preferably substantially harder than the material used to form the bearing lining layer 16. Examples of preferred hard particles 32 are listed in Table 1.

Material form Yes Net element: W, Ta, Cr, Si, Ti Carbide: SiC, B ₄ C, Cr ₂₃ C ₆ , TaC, TiC, WC, ZrC oxide: Al ₂ O ₃ , Cr ₂ O ₃ , Fe ₂ O ₃ , SiO ₂ , TiO, ZrO ₂ Nitride: BN (hexagonal), BN (cubic), Si ₃ N ₄ , AlN Boride: Cr ₃ B ₂ , TiB ₂ , TaB ₂ Silicides: TaSi ₂ , Fe ₄ Si ₃

Hard particles 32 will preferably be selected with respect to chemical compatibility, conformity and embedding compatibility with the bearing lining layer 16. The hard particles 30 are preferably embedded at a depth from the outer surface 36 to 0.1 to 1 mu m. Layer 30 of hard particles 32 may be embedded using any suitable method, but preferably bearing lining layer 16 in a container containing hard particles 32 selected for a given application. The partially completed bearing assembly containing this bonded metal backing 12 will be embedded by tumbling. The hard particles 32 may be embedded in the bearing lining layer 16 to influence the impact of the hard particles 32 on the surface 36 of the bearing lining layer 16 to allow the hard particle layer 30 to be formed. Known tumbling means can be used. The duration, speed, container size, and other well-known factors change the depth at which the hard particles are embedded and the volume or weight fraction of the metal matrix from the bearing lining layer 16 in the hard particles 32 to hard particle layer 30. Can be adjusted. A method for embedding alumina hard particles on a metal bearing face is disclosed in US Pat. No. 5,433,531, the entire contents of which are incorporated herein by reference. Hard particles have an average size in the range of 0.5-150 μm. Hard particles 32 will preferably range from 0.5 to 5.0 percent of the surface area of the hard particle layer 30.

After the step of embedding the hard particles 32 to form the hard particle layer 30, the method of the present invention finalizes the profile of the outer surface 36 of the bearing lining layer 16, such as by machining or grinding. It may also include finishing to dimension. Finishing the profile preferably removes the material from the surface 36 to a minimum so that the thickness of the hard particle layer 30 is kept to the maximum possible size.

After finishing the profile of the bearing lining layer 16 comprising the hard particle layer 30, the method preferably comprises plating the barrier layer 22 when the barrier layer 22 is employed. Doing. This step may be done after the step of cleaning or degreasing the outer surface 36 of the hard particle layer 20. Materials and methods for degreasing are well known.

After plating the barrier layer 22, the method preferably includes plating the overlay or overplate layer 24. Materials for forming the overlay layer 24 are well known, such as plating methods for forming this layer. This step may be done after the step of cleaning or degreasing the outer surface 36 of the layer when the hard particle layer 20 or barrier layer 22 is employed. Materials and methods for degreasing are well known.

After plating overlay 24, the method includes plating the protective coating 28 of the thin film layer, preferably tin. This step may be done after the step of cleaning or degreasing the outer surface of the overlay layer 24. Materials and methods for degreasing are well known. Once the overplate is coated, a conventional thin film flash coating (not shown) may be applied to the bearing 10.

It is apparent that various modifications and variations of the present invention are possible in light of the present technology. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. The invention is defined by the claims.

Claims (16)

A metal backing layer having a bearing face; A metal bearing liner layer attached to the bearing face of the metal backing layer, the metal bearing liner layer having a layer of hard particles embedded therein at a depth of up to 0.1 to 1 μm only on an outer surface thereof; And And at least one metal overplate layer deposited on an outer surface of the metal bearing liner layer. The method of claim 1, wherein the hard particles comprise a metal alloy having a hardness greater than the hardness of the metal bearing liner layer and a material selected from the group consisting of pure elements, metal carbides, metal silicides, metal nitrides and metal borides. Multi-layer sliding bearing According to claim 2, wherein the group is W, Ta, Ti, Cr, Si, SiC, B ₄ C, Cr ₂₃ C ₆ , TaC, TiC, WC, ZrC, Al ₂ O ₃ , Cr ₂ O ₃ , Fe ₂ Consisting of O ₃ , SiO ₂ , TiO, ZrO ₂ , BN (hexagonal system), Cr ₃ B ₂ , TiB ₂ , TaB ₂ , BN (isoaxial system), Si ₃ N ₄ , AlN, TaSi ₂ and Fe ₄ Si ₃ Multi-layer sliding bearing, characterized in that. delete The multi-layer sliding bearing according to claim 1, wherein the hard particles in the hard particle layer comprise 0.5 to 5.0 area percent of the hard particle layer. A metal backing layer having a bearing face; A metal bearing liner layer attached to the bearing face of the metal backing layer, the metal bearing liner layer having a layer of hard particles embedded therein at a depth of up to 0.1 to 1 μm only on an outer surface thereof; A metal barrier layer deposited on an outer surface of the metal bearing liner layer, the metal barrier layer also having an outer surface; And And at least one metal overplate layer deposited on an outer surface of the metal barrier layer. The method of claim 6, wherein the hard particles include a metal alloy having a hardness greater than the hardness of the metal bearing liner layer and a material selected from the group consisting of pure elements, metal carbides, metal silicides, metal nitrides and metal borides. Multi-layer sliding bearing, characterized in that. According to claim 7, wherein the group is W, Ta, Ti, Cr, Si, SiC, B ₄ C, Cr ₂₃ C ₆ , TaC, TiC, WC, ZrC, Al ₂ O ₃ , Cr ₂ O ₃ , Fe ₂ Consisting of O ₃ , SiO ₂ , TiO, ZrO ₂ , BN (hexagonal system), Cr ₃ B ₂ , TiB ₂ , TaB ₂ , BN (isoaxial system), Si ₃ N ₄ , AlN, TaSi ₂ and Fe ₄ Si ₃ Multi-layer sliding bearing, characterized in that. delete The multilayer sliding bearing according to claim 6, wherein the hard particles in the hard particle layer comprise 0.5 to 5.0 area percent of the hard particle layer. Fabricating a metal backing layer having a bearing face; Attaching a metal bearing liner layer having an outer surface to the bearing surface of the metal backing layer, Embedding the layer of hard particles to a depth of 0.1-1 μm only on the outer surface of the metal bearing liner layer; And Depositing at least one metal overplate layer on an outer surface of the metal bearing liner layer. The method of claim 11, And after depositing the hard particles and before depositing the metal overplate layer, finishing the outer surface of the metal bearing liner layer in at least a portion of the hard particle layer. . 13. The method of claim 12, And degreasing the outer surface of the metal bearing liner layer prior to depositing the one or more metal overplate layers after finishing the outer surface of the metal bearing liner layer. Fabricating a metal backing layer having a bearing face; Attaching a metal bearing liner layer having an outer surface to the bearing surface of the metal backing layer, Embedding the layer of hard particles to a depth of 0.1-1 μm only on the outer surface of the metal bearing liner layer; Depositing at least one barrier layer on an outer surface of the metal bearing liner layer; And Depositing at least one metal overplate layer on an outer surface of the barrier layer. 15. The method of claim 14, And after depositing the hard particles and before depositing the barrier layer, finishing the outer surface of the metal bearing liner layer in at least a portion of the hard particle layer. 16. The method of claim 15, And degreasing the outer surface of the metal bearing liner layer after the finishing of the barrier layer after finishing the outer surface of the metal bearing liner layer.

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