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Technical Paper

Development of Resin Overlay Bearing Material for Recent Automotive Engine

2017-03-28
2017-01-0460
The number of vehicles with engines using idling stop systems and hybrid systems to improve fuel consumption has recently been increasing. However, with such systems the frequent starts and stops of the engine, where the oil film between the bearings and shaft is squeezed out and direct contact between the components is more likely, can result in increased wear of the engine bearings, particularly in the main bearing. Bearings with resin overlays have been shown to display superior resistance to wear from such start-stop cycles. Moreover, cast iron shafts without quenching treatment have also been used in engines for cost reduction. Because the cast shaft has low hardness and unstable surface graphite after abrasive finishing, increase in the wear amount cannot be suppressed by conventional resin overlay in comparison with steel shaft. Therefore, the resin overlay with improved wear resistance achieved by adding hard particles was developed.
Technical Paper

Effect of Noise Factors on Seizure Limit Performance in Engine Main Bearings

2016-04-05
2016-01-0488
In order to determine the seizure limit of the main bearings of passenger vehicles under actual operating conditions, evaluations were conducted in environments containing noise factors (Various factors which designer cannot adjust and which make function vary were defined as noise factors in this paper.) [1,2] It was shown that noise factors have an effect on seizure limit performance in relation to performance under ideal test conditions (test conditions in which no noise is present). In relation to oil properties, the results showed that a reduction in viscosity as a result of dilution affected seizure limit performance. In relation to the shape of the sliding sections of the test shaft, seizure limit performance declined in a shaft in which the central section was swollen (“convex shaft” below).
Technical Paper

Development of Lead-Free Copper Alloy Bearing Material with Improved Conformability

2015-04-14
2015-01-0520
There has been a requirement for automotive bearings materials to be free of the toxic material lead, in accordance with ELV regulations and from the perspective of environmental problems. Currently, bismuth is used as a replacement for lead in copper alloy based main journal bearings and connecting rod bearings for automotive engines. In recent years, there has been changing to lead-free materials for truck engine bearings. Compared with automotive engines, lots of contaminations in the oil and local contact between the shaft and bearings can occur in truck engines. The ability to tolerate contamination and local contact is therefore required for truck engine bearings. In this development, we find that the addition of 8 mass% bismuth and 1.5 mass% molybdenum carbide particles into copper-tin alloy is effective for improving the ability which allow the contamination and local contacts. The development of above mentioned lead-free copper alloy bearing material is described here.
Technical Paper

A Study of Resin Overlay Bearing Material for Recent Automotive Engines

2013-04-08
2013-01-1394
With increased awareness of environmental issues and regulations, developments for recent automotive engines are progressing towards engines with low fuel consumption. Due to these changes, automotive engine bearings are increasingly used in harsher environments, with higher loading and corresponding wear. From this background, resin overlays, where solid lubricant is dispersed in a resin binder, are being developed. Resin overlays show excellent sliding properties under boundary lubrication conditions, and are known to have superior wear and fatigue resistance compared with conventional aluminium based bearings. However, while conventional resin overlay bearings display excellent sliding properties, they tend to have inferior seizure resistance compared to Al-Sn-Si alloy bearings. In this study, by optimizing the strength of the resin overlay layer with addition of calcium carbonate particles, a resin overlay with equal wear resistance but improved seizure resistance was developed.
Video

Development of High Strength Polymer Based Bearing for Automotive Parts under Boundary Lubrication

2012-05-23
Composite bearings of PTFE as the base material have been widely used for automotive parts. However, in recent years, due to downsizing, faster sliding speeds, and tendency to increase the bearing load with high performance, particularly for boundary lubrication conditions, the PTFE-based composite bearing is often worn, making it difficult to apply to some applications. A high strength polymer was selected as an alternative to PTFE base material, and the mechanical properties and performance in a start-stop test, reciprocating sliding test and seizure test were evaluated. Focusing on the characteristics of high strength, by applying a PEEK resin, in each evaluation, it was confirmed that superior performance was achieved compared with a conventional PTFE based composite bearing. Presenter Yohei Takada, Daido Metal Co., Ltd.
Technical Paper

Development of High Strength Polymer Based Bearing for Automotive Parts under Boundary Lubrication

2012-04-16
2012-01-0751
Composite bearings of PTFE as the base material have been widely used for automotive parts. However, in recent years, due to downsizing, faster sliding speeds, and tendency to increase the bearing load with high performance, particularly for boundary lubrication conditions, the PTFE-based composite bearing is often worn, making it difficult to apply to some applications. A high strength polymer was selected as an alternative to PTFE base material, and the mechanical properties and performance in a start-stop test, reciprocating sliding test and seizure test were evaluated. Focusing on the characteristics of high strength, by applying a PEEK resin, in each evaluation, it was confirmed that superior performance was achieved compared with a conventional PTFE based composite bearing.
Journal Article

A Study on Wear Progress of Plain Bearing under Mixed Lubrication Condition

2011-04-12
2011-01-0609
Recently, automotive engines have been operating under harsh conditions of high-power, low viscosity oil and increase of start-stop (e.g. idling stop). In plain bearing used within engine, as oil film thickness decreases, the frequency of direct contacts on the sliding surfaces between the shaft and the bearing are gradually increasing. In fact, the plain bearings for engines would tend to be used under mixed lubrication and the contacts of the surface roughness asperities sometimes occur between the shaft and the bearing. As a result, the bearing wear on the sliding surfaces is accelerated by the contacts of the roughness asperities. In order to predict the bearing performance exactly, it is very important to understand the change progress of the geometric shape of sliding surfaces caused by the wear.
Technical Paper

Basic Characteristics of Lead-free Aluminum Alloy Bearings with Low Frictional Property of Adhered Molybdenum Disulfide

2007-04-16
2007-01-1570
A newly developed bearing is a lead-free aluminum alloy bearing with low frictional layer which consists of molybdenum disulfide in thicknesses of sub-micron levels on the bearing surface without required binders such as resin. The new bearing had a 50% lower static friction coefficient compared to the conventional aluminum alloy bearing, and exhibited comparable anti-seizure property and fatigue strength to the conventional bearing by evaluation of rig tests. These rig tests verified that the new bearing showed excellent frictional reduction properties. This paper describes details and performances of this newly developed bearing.
Technical Paper

Development of Lead Free Copper Based Alloy for Piston Pin Bushing Under Higher Load Engines

2006-04-03
2006-01-1105
As the recent engines are designed for higher performance, piston pin bushing used for small end of connecting rod must endure higher dynamic load and oil temperature conditions. Therefore, the bushing is required higher wear resistance and anti-corrosion. And it is also expected to develop the bushing without lead due to environmental concerns. In this report, lead free copper based bushing alloy was studied. At first, in order to keep the anti-seizure property without lead, we studied the effects of hard particles added into copper based alloy. Second, we evaluated the effect of addition of hard particles on wear resistance and anti-corrosion.
Technical Paper

Studies on Lead-free Resin Overlay for Engine Bearings

2006-04-03
2006-01-1104
Resin-based overlays as lead-free bearing materials for automobile engines are experimentally studied using tribology testing apparatus and an engine bench test rig. A resin overlay newly proposed is composed of Polybenzimidazole (PBI) as the base resin and solid lubricant Molybdenum disulfide (MoS2) as an additive. PBI has high temperature performance and good adhesion and physical strength under higher temperatures. Consequently, a PBI-based overlay has good sliding properties in terms of wear resistance and fatigue resistance. The resin overlay shows applicability to automobile engine bearings which are used under high loads.
Technical Paper

Development of Lead Free Overlay for Three Layer Bearings of Highly Loaded Engines

2005-04-11
2005-01-1863
Emission control and other restrictions prescribed in the EU's recent EUROIV regulations require automobile manufacturers to decrease NOX and PM (Particulate Matter) in exhaust emissions. Diesel engines in recent years tend to have higher cylinder pressure in pursuit of higher performance and meeting emission regulations. At the same time, under the ELV (End-of-Life Vehicles) regulation, use of lead, which is an environmental pollutant, in automobile parts has become increasingly difficult in recent years. Accordingly, we have developed lead-free overlay for tri-metal copper bearings for applications of highly specific load. We chose a dual-layer structure, bismuth and silver overlay. This type of structure can create fatigue resistance without compromising the two advantages of lead overlay: conformability and anti-seizure property.
Technical Paper

Study on Eco-Friendly Oil on Water Drop Metalworking Fluid

2004-03-08
2004-01-0789
A new environmental friendly method to supply metalworking fluid called Oil on Water Drop is proposed. In this study, the obtained results using this new method are compared to the dry cutting one in the machining of oil grooves in engine bearings. Conventional machining of engine bearings is carried out in the dry cutting condition; however, it was found that using the new Oil on Water Drop method the machining performances were greatly improved. In terms of machining tool life, a twofold increase was obtained, while an improvement in the machining error led to a considerable reduction in the rejection of parts made in the production line.
Technical Paper

Development of Lead Free Copper Based Alloy for Three Layers Bearings under Higher Load Engines

2004-03-08
2004-01-1600
As the recent engines are designed for higher performance and better efficiency, three layers bearings must endure under heavy dynamic load and higher speed conditions. And it is also expected to develop the bearing without lead due to environmental concerns. In this report, a lead free copper based bearing alloy was studied. At first, in order to keep the anti-seizure property without lead, we studied the effects of bismuth and molybdenum carbide particles addition into the copper based bearing alloy. Secondly, we studied the influence of axial bearing relief to keep a conformability under high load condition.
Technical Paper

Development of Multi-layer Aluminum-Tin-Silicon Alloy Bearing for Automotive Diesel Engine

2003-03-03
2003-01-0050
Recent engine bearings are operating under severe conditions to support such engine requirements as lower fuel consumption, longer life and protection of global environment. On Al-Sn-Si alloy bearings, it has some issue that fatigue may occur on the bearing alloy under severe condition such as in automotive diesel engines. Higher strength of alloy, which allows the fatigue resistance, can be obtained by solid solution treatment at higher temperature in general. But at the same time it makes intermetallic compounds with less bonding strength between intermediate layer and steel backing. A new bearing without lead has been developed by applying the heat treatment of bimetal and adequate intermediate layer for the process, consequently concluded to have the higher fatigue strength, with usual property on Al-Sn-Si alloy bearings.
Technical Paper

Parametric Study for Design Factors on Engine Bearings by using TEHL Analysis

2002-03-04
2002-01-0298
As the downsizing and lightening of the engine are designed, the compact and lightweight of the housing should be required. Therefore, both the engine bearing and the housing are greatly deformed under the severe condition, and a heat generation due to the friction loss increases in the bearings. In this study, on the connecting rod bearing for the automotive engine, the bearing design factors as the oil inlet temperature, the rotational speed, the bearing clearance and the bearing length, are changed as a parameter. The influences of the design factors for the performance of the connecting rod bearing are investigated by using TEHL analysis (Thermo ElastoHydrodynamic Lubrication theory analysis).
Technical Paper

Theoretical Analysis of Engine Bearing Considering Both Elastic Deformation and Oil Film Temperature Distribution

2001-03-05
2001-01-1076
Recently, the bearing performances have been analyzed by elastohydrodynamic lubrication theory (EHL). However, the oil film temperature is constant within a bearing clearance on this theory. As modern automotive engines are running at high rotational speed, the change of the oil film temperature is remarkable within a bearing clearance. The bearing performances are influenced by the distribution of the oil film temperature. Therefore it is also necessary for the analysis of the bearing performances to consider the effect of the oil film temperature distribution by thermo elastohydrodynamic lubrication theory (TEHL). In this study, the effects of the bearing performances are investigated on connecting rod bearing in general gasoline engine by TEHL. Furthermore, oil film thickness, oil film pressure and oil film temperature of TEHL results are compared with those of EHL.
Technical Paper

Development in Polymer Based Bearing Material for Automotive Shock Absorbers

2000-03-06
2000-01-0097
Recently, as for the rod guide bush bearing materials for shock absorbers, lower friction and the improvement of durability are required along with ride quality and longer life of automobile. Usually, lead is contained in bearing materials. However, the addition of the lead in bearing material is being restricted from the earth environmental problem. Bearing materials for shock absorbers are composite material consists of steel backing and covered with polymer surface layer. This basic material structure hasn't been changed till now, though it has been improved by changing its components and compositions based on the customer's requirement. Bearing material with both lower friction and excellent wear resistance has been developed in this study.
Technical Paper

A Study on Engine Bearing Wear and Fatigue Using EHL Analysis and Experimental Analysis

1999-05-03
1999-01-1514
The possibility of predicting engine bearing durability by elastohydrodynamic lubrication (EHL) calculations was investigated with the aim of being able to improve durability efficiently without conducting numerous confirmation tests. This study focused on the connecting rod big-end bearing of an automotive engine. The mechanisms of wear and fatigue, which determine bearing durability, were estimated by comparing the results of EHL analysis and experimental data. This comparison showed the possibility of predicting the wear amount and the occurrence of fatigue by calculation.
Technical Paper

A Study for Wear and Fatigue of Engine Bearings on Rig Test by Using Elastohydrodynamic Lubrication Analysis

1999-03-01
1999-01-0287
Engine bearings today are operating under very harsh conditions. Consequently, a wear propagates for a short time and a fatigue sometimes occurs on the bearings. In present study, on the rig test machine, the operating conditions of engine bearing were simulated to reproduce the bearing damage. The bearing wear was measured until the fatigue crack occurred. The bearing wear increased at the edges of the bearing length and the crack also was observed near the edges. The experimental results were compared to the calculated results based on the elastohydrodynamic lubrication (EHL) theory. The correlations between the bearing damage and the bearing performances by the theoretical analysis were investigated.
Technical Paper

Properties of Engine Bearings Lubricated with Low HTHS Viscosity Oil

1998-02-23
980702
Properties of engine bearings were investigated with different bearing materials and different HTHS viscosity oils by means of both an engine test and a rig test. The rig test well simulated the bearing wear which occurred in the engine test. Lead-bronze bearings with lead-tin-indium overlay gave the least amount of wear in operating under high speed and heavy load conditions even with low HTHS viscosity oil. Aluminum bearings without overlay gave good wear resistance in the case of no seizure occurrence. The wear amount of bearings were well correlated with HTHS viscosity, not with kinematic viscosity.
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