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Development of High Strength Aluminum-Zinc-Silicon Alloy Bearing with Polymer Overlay

Daido Metal Co., Ltd.-Takeshi Hoshina, Seiji Amano, Motohiko Koushima, Kei Ishikura
Published 2019-04-02 by SAE International in United States
Recent automotive engine developments have made great progress in protecting the global environment and in meeting exhaust gas regulations and fuel economy regulations. As a result, engine bearings tend to be used under severe conditions such as higher specific load onto the bearings and with low viscosity of lubricating oil. Aluminum alloy bearings are widely adopted as main bearings and connecting rod bearings in gasoline and diesel engines for passenger cars, and generally Al-Sn-Si alloy bearings without an additional overlay are used. Although these Al-Sn-Si alloy bearings have good anti-seizure properties and excellent running-in-properties, their material strength under high temperature conditions is not sufficient because of the low melting point of Sn phase contained in the alloy, and they could potentially result in damage to the bearing as seizure and fatigue under these conditions.In such cases, Cu-Pb-Sn alloy bearings with lead-based overlay are usually applied. On the other hand Al-Zn-Si alloy bearings with bismuth overlay are also becoming to be applied from the view point of superior corrosion resistance and lower cost. This means that…
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Development for Polymer Overlay Bearing Material for Recent Automotive Engine

Daido Metal Co. Ltd.-Kenji Nimura, Hiroki Kobayakawa, Motohiko Koushima, Seiji Amano
Published 2018-04-03 by SAE International in United States
The number of vehicles with engines using idling stop systems and hybrid systems to improve fuel consumption has recently been increasing. With idling stop systems the engine is switched off when waiting at city traffic lights or stopping on the road, suppressing the fuel usage which leads to improved fuel consumption. 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 to occur, can result in increased wear of the engine bearings. As a countermeasure, recent engine bearings can have thin coatings based on polymeric resin material (polymer overlays) applied to the bearing surface, which are known to have good bearing properties such as wear resistance and low friction characteristics. In addition to the use of idling stop systems, certain automotive engines are also designed with increasingly high power output, which of course increases the applied load on the engine bearings, and therefore bearing materials that can withstand such high loads are…
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Effect of Noise Factors on Seizure Limit Performance in Engine Main Bearings

Daido Metal Co., Ltd.-Motohiko Koushima
Honda-Takashi Izawa
Published 2016-04-05 by SAE International in United States
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). With regard to partial contact between the shaft and the bearings, it was shown that as the angle of partial contact increases, the seizure limit declines, and that the magnitude of this effect differs depending on the material used in the bearings.
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Development of Lead-Free Al-Sn-Si Alloy Bearing for Recent Automotive Engines

Daido Metal Co. Ltd.-Akihiro Kose, Motohiko Koushima, Yuki Kawashima, Kouji Zushi
Daido Metal USA Inc.-Tomohiro Ukai
Published 2014-04-01 by SAE International in United States
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. These operating conditions require bearings with both conformability and fatigue resistance.From the above background, various aluminum alloy bearings have previously been developed, including materials with solid solution treatment to improve their properties, and alloys which can be used with or without an overlay [1, 2, 3]. These materials are known to have good conformability and fatigue resistance.However, while conventional Al-Sn-Si alloy bearings display excellent sliding properties, due to the unceasing trend for engine downsizing, more conformability is required.In this study, by optimizing dispersion of the soft tin phase in Al-Sn-Si alloys, a bearing material with equal fatigue resistance and further improved conformability was developed. The performance of the developed Al-Sn-Si alloy bearings was confirmed with rig tests and engine bench tests.
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Comparative Studies of Connecting Rod Bearings Design on Capability to Discharge Foreign Particles

Daido Metal-Motohiko Koushima
Daido Metal Co Ltd.-Osamu Ishigo, Tadamichi Tamura, Yuto Otsuki, Hiroshi Itoigawa, Atsushi Okado
Published 2010-04-12 by SAE International in United States
Foreign particles remaining in an engine cause bearing trouble on rare occasions. It is required to promptly and effectively discharge foreign particles from the bearing clearance space to improve reliability of the engine. In this paper, the bearing configuration of at the parting line between upper and lower bearings which are capable of discharging foreign particles are experimentally studied. Tests were conducted for fundamental visualization of oil flow and particles. As a result, the behavior of the particles in the bearing clearance space and the effects of the bearing configurations were well demonstrated. In the bench test using an actual engine, the bearing configuration with grooves at the parting line of the bearing demonstrated the effectiveness to prevent bearing damage caused by foreign particles. The influence of the bearing configurations on oil flow rate was confirmed not to increase the flow rate.
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