• Tribology and Lubricants
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• 제25권6호
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• pp.409-413
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• 2009

This paper presents the hardness and friction characteristics of pb-free pin-bush bearing metal, which is manufactured by a centrifugal casting technology. A bronze metal with a high hardness and low friction properties is usually used for Diesel engine pin-bush bearing and high pressure cylinder. Pb-free metal for pin-bush bearings shows a little high hardness of 120 Hv compared with that of a conventional Pb bearing metal of 100~110 Hv. In general, the friction coefficient of pin-bush bearings is affected by a rotating speed and a load for various rubbing contact modes. But a contact load is more influential parameter when the contact rubbing mode transits from a mixed lubrication to a dry friction contact. The experimental result shows that the friction coefficient is more unstable at the dry contact mode compared with that of other two rubbing modes such as oil film contact and mixed friction conditions.

• Tribology and Lubricants
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• 제24권6호
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• pp.315-319
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• 2008

This paper presents the interface bonding characteristics between a phosphor bronze and a steel plate for pin-bush bearings. The pin-bush bearing is an important component in which is used to reduce a friction loss and a wear against the piston pin. The pin-bush bearing is manufactured by hot-pressing a phosphor bronze and a back metal of a steel plate. This paper investigated the bonding interface characteristics in which is manufactured by melting a copper based bronze and a steel plate. The hardness from the inner surface of a bronze to the outer one of steel has been measured using a Vickers hardness tester. The experimental results show that the hardness of a bronze is superior to that of the conventional bronze and the transient hardness of pin-bush bearings is gradually increasing to the hardness of the steel back metal. This means that the bonding interface zone of pin-bush bearings may be fabricated by defusing a bronze to the steel plate due to a density difference between two materials.

• Tribology and Lubricants
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• 제24권1호
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• pp.21-26
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• 2008

A pin bush bearing is one of the most important element in the piston engine which is joined a piston to a connecting rod. A pin bush is suffered by heat and changeable repeat loads, which are come from the explosive gas heat and pressures during a reciprocating stroke. Therefore, a tribological behavior of pin bush bearings is very severe compared to other parts of a piston assembly. To keep a stable operation of pin bush bearings effectively, it would be satisfied with proper oil film strength for severe operating conditions and durability, which are strongly related to the oil film thickness, oil film pressure, and a friction loss power. The computed results show that the viscosity of engine oils slightly affects to the minimum oil film thickness and oil film pressure distribution, but is an influential parameter on a total friction loss power. Thus the low viscosity engine oils for an increased operation condition should select a high level of base oil and add a viscosity index improver as an oil film additive.