Masakazu Iguchi

Non-Contact Suspension and Propulsion Technology

SUMMARY As a result of extensive research and development in several countries, the technologies of magnetic suspension and linear electric drives are becoming available for transportation applications. The successful demonstration and operation of prototype vehicles has established the technical viability of these systems. Several urban transit or shuttle services, with magnetic suspension and/or linear motor propulsion are likely to be operational within 3-4 years. After the final stages ofdevelopment and rigorous testing, high speed systems are likely to be an option for intercity implementation by the end of the decade. This paper presents a report on the worldwide status of R&D and test programs of non-contact suspension and propulsion technology for guided ground transport.

Development of aseismic design of piping, vessels and equipment in nuclear facilities

Abstract This report involves the development of aseismic design procedures of piping, vessels and equipment in Japan. These mechanical structures show their various characteristics of vibration. Pressure boundaries, a containment vessel and safety systems belong to such structures. The vital components of nuclear power plants are classified to “A” class according to the classification for the aseismic design in Japan. All components in “A” class are required to be based on dynamic earthquake-resistant design, of which level is decided in consideration of local seismisity. For dynamic design purposes, the following processes are the most important: 1. estimating eigenfrequencies and modes of the system; 2. estimating its damping characteristics; 3. estimating the behavior of the system during strong earthquakes; 4. deciding the design criteria, especially the allowable stresses to earthquake loadings.

Promotion of the Program of Advanced Safety Vehicles for 21st Century

Facing the need to improve the safety of the structure and performance of automobiles, the Ministry of Transport is promoting to develop the advanced safety vehicles (ASVs) for practical use. ASVs are automobiles that are much safer and easier to use than existing models because they make the most of rapidly advancing electronics technology in addition to traditional technologies. The Ministry of Transport established the Study Group for Promotion of Advanced Safety Vehicles to develop ASVs for practical use by the early 21st century. The group has been promoting a 5-year plan from 1991. In 1995, the last year of the plan, the group will draft the guiding principles of ASV technology to develop and realize ASVs in the future.

OPTIMUM ADHESION CONTROL OF TRACTION MOTORS BY A DIGITAL FILTER

SUMMARY The maximum available adhesion under all weather conditions has been recognized as a cost effective means in the field of traction motors. In the above situation the problem is how to detect adhesion limits under various conditions. In this paper it is described that a digital filter with a new algorithm can detect a symptom of slip and that optimum adhesion is maintained by use of this signal.

Axle-vibration of locomotives just before slipping.

The slip of a locomotive wheel is one of the sources of torsional vibration of the axle. Great efforts to prevent such vibration have been made by locomotive builders and railroads. But now they are trying to use this vibration in order to prevent slipping and to utilize adhesion. This paper describes the results of the experiments carried out on a test-rig which is a one-third scale model. An occurrence of vibration at the axle immediately before slipping is confirmed, and this vibration is common almost under all conditions. When the driving torque approaches the adhesion limit, the damping due characteristic near the adhesion limit decreases. Then axle-vibration can easily occur by the changing of the axle load and the traction coefficient. Experiments confirmed that this phenomenon can be used for adhesion control.

DESIGN STRATEGY FOR WHEEL AND RAIL PROFILES IN ORDER TO DECREASE THE WEAR OF WHEELS AND RAILS

SUMMARY Relationship between creep force and a slip angle has the same character as between aerodynamic force and an attack angle. The characteristic of creep force is changed according to the contact condition between a wheel and a rail. It is strongly affected by the sectional profile of a wheel and a rail. Old-time steam locomotives which had long and fixed axlebases and big radius wheels had to use flange for curving. Profiles of wheels had little effect on vehicle dynamics in this situation. Now most of high-speed electric cars in Japan use two-axle trucks with wheels whose diameters are smaller than 1 m. Suitable profiled wheels and rails can assure good performance of rail vehicle dynamics, such as curving without flange contacts and high stability for hunting motion. In this paper a new design strategy of wheel and rail profiles is described. The profiles for wheels and rails are derived by a theoretical procedure like the involute curve for gears.

Study on a growth mechanism and a prevention of corrugated and wavy wear.

This paper is concerned with a growth mechanism and a prevention measure of corrugated and wavy wear that often occurs in transportation machines. Theoretical analysis, computer simulation and experiments were conducted. We made clear one of the causes of the growth of the wavy wear and controlled its growth intentionally and succeeded in decreasing wavy wear amplitude by equipping a sprung mass with a dynamic damper.