Lubricating Materials Laboratory

Laboratory, Japan

Lubricating Materials Laboratory

Laboratory, Japan
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Doi H.,Vehicle Mechanics Laboratory | Miyamoto T.,Vehicle Mechanics Laboratory | Suzumura J.,Lubricating Materials Laboratory | Nakahashi J.,Vehicle Dynamics Laboratory | And 2 more authors.
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2012

A number of flange climb derailments have occurred in sharp curves or curves with turnouts within relatively short accumulated running distances subsequent to wheel turning. This indicates that a change in the condition of the turned wheel surface might be a factor inducing flange climbing. Through several experiments and numerical simulations, the authors investigated the relationship between the running safety of a vehicle and its wheel surface condition especially in terms of wheel/rail friction. Furthermore, lubrication just after wheel turning was proposed as a countermeasure to flange climb derailments and its effectiveness and persistence were evaluated.


Kikawa S.,Lubricating Materials Laboratory | Suzumura J.,Lubricating Materials Laboratory | Sone Y.,Materials Technology Division | Nakamura K.,Lubricating Materials Laboratory | And 2 more authors.
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

A long-life gear oil for electric railway trains was developed to reduce the workload and cost of gear unit maintenance. A semi-synthetic base oil, a mixture of polyalphaolefin (PAO) and highly purified mineral oil, was used in the developed gear oil in order to improve high temperature oxidation stability. The composition of additives was also modified to enhance oxidation stability. In an accelerated oxidation test (Indiana stirring oxidation test at 135°C /96 hours), the developed gear oil demonstrated sufficient oxidation stability to enable an electric train to run 1,200,000 km without an oil change. Reliability at low temperatures was also shown to be better compared with existing gear oils, because the viscosity at low temperatures and the pour-point was reduced by virtue of the semi-synthetic base oil.


Hibino S.,Lubricating Materials Laboratory | Nakamura K.,Lubricating Materials Laboratory | Hosoya T.,Lubricating Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2012

The "interim greasing" method is one of the general solutions for extending the lifespan of grease, and has been adopted for some types of induction traction motors. However, the conventional way of planning interim greasing requires leaving some empty space to refill additional grease due to the limited room. Accordingly, trouble sometimes occurs due to insufficient lubrication during the initial stages of the motor operation. To solve this problem, a new device was designed which enables grease refilling without providing an empty space by replacing the deteriorated grease with the less deteriorated one inside the grease pocket.


Suzumura J.,Lubricating Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2016

This paper describes a fundamental study of the preventive measures against electrical pitting on rolling bearings by using electrically conductive lubricating grease. In order to evaluate the ability to prevent the electrical pitting on rolling bearings of several types of grease into which conductive nanometer-scaled carbon particles, or "nanocarbon" particles, have been dispersed, bearing rotation tests were conducted when an electric current was turned on. It was concluded that the electrically conductive grease has the ability to prevent electrical pitting, or "ridge marks", if the electric current density at the points of rolling contact is lowered.


Suzumura J.,Lubricating Materials Laboratory | Sone Y.,Lubricating Materials Laboratory | Yamashita D.,RIKEN
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013

This paper describes some experimental investigations of on-the-spot X-ray analysis of interfacial substances between the wheel and the rail such as iron rust and lubricants, which have an influence on the adhesion coefficient between wheel and rail. A portable X-ray analyzer called "XRDF" was fitted with a fixture for setting the XRDF head above the rail by making it override the rail. By conducting in situ XRDF analysis of rail surface substances, insights were obtained into the tendencies regarding the decrease of iron rust and the spreading characteristics of lubricants during the passage of vehicles.


Sone Y.,Lubricating Materials Laboratory | Suzumura J.,Lubricating Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2010

This study focused on attempts to use traction oil as a wheel/rail lubricant. Traction oil is a recently developed lubricant material, and is thought to provide a higher traction coefficient than conventional lubricating oil. In laboratory tests, a traction coefficient of 0.14 was obtained for traction oil, and the relationship between traction coefficients and slip rates was found to depend mainly on the oil type. It was also clarified that the anti-wear properties of traction oil could be controlled using a certain quantity of anti-wear additive. It has been proved that traction oil is promising as a wheel/rail lubricant, but further efforts are required to clarify the related effects on other significant factors such as lateral force.

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