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Yamamoto D.,Vehicle Noise and Vibration Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

In the study presented in this paper, calculation of the contact patch between a measured wheel tread profile and a designed rail shape carried out strictly by using a general software program called TED/CPA in order to investigate their contact characteristics. A calculation method to obtain the creep coefficient was proposed focusing on a contact patch subject to multi-point contact. This proposed method was then applied to contact conditions between the measured wheel tread profile of a commercial vehicle and the designed rail shape. Results showed that the contact patch shape is composed of many contact areas due to wheel tread unevenness, and the estimated creep coefficient may be smaller than the Kalker's theoretical value. Source


Umehara Y.,Running Gear Laboratory | Ishiguri K.,Running Gear Laboratory | Yamanaga Y.,Running Gear Laboratory | Kamoshita S.,Vehicle Noise and Vibration Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

Bogie angle linked steering trucks have an excellent curving performance in circular curve sections. In order to gain even greater curving performance, a power-assisted steering system was developed for reducing wheel lateral forces in transition curve sections by generating the control force in the turning direction of the steering truck. In addition, a steering electro-hydraulic actuator was designed for reducing lateral forces in transition curve sections while preventing wrong direction steering operation which is the biggest problem with active steering systems. Finally, confirmation was obtained through running test on a test line that this steering actuator improved steering performance and maintained the fail-safe function. Source


Koganei R.,Vehicle Noise and Vibration Laboratory | Watanabe N.,Running Gear Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2015

A 'Virtual Running Test Environment' has been in development, based on Hardware In the Loop Simulation (HILS) technology to emulate, in detail, railway vehicle motion on real tracks. The existing HILS system only reproduces the rigid body motion of a railway vehicle while running. In order to create a more realistic virtual running test environment, trials have been conducted to expand the frequency range of the HILS system to include and evaluate the elastic vibration of railway vehicle carbodies. This paper reports on frequency enhancement of the test equipment and about the construction of the numerical model including reproduction of elastic vibration. Source


Tomioka T.,Vehicle Noise and Vibration Laboratory | Takigami T.,Vehicle Noise and Vibration Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

Rotation of wheelset(s) with small mass imbalance can induce relatively large carbody vibration and worsen ride comfort. Since the excitation force due to an imbalanced wheelset is transmitted from bogie to carbody through a traction link, the authors have developed a displacement-dependent rubber bush for traction links, which has a small gap between the rubber and the inner fixture to prevent this excitation. Unit testing of the rubber bushes to check their stiffness and durability, excitation tests using a full-scale test vehicle to verify the vibration isolation performance, and running stability testing with a bogie, have been carried out. A series of running tests on a commercial line were then conducted and the effectiveness of the displacement-dependent rubber bush was confirmed under actual service condition. Source


Sugahara Y.,Vehicle Noise and Vibration Laboratory | Watanabe N.,Eunning Gear Laboratory | Takigami T.,Vehicle Noise and Vibration Laboratory | Koganei R.,Vehicle Noise and Vibration Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

Suppression of vertical bending vibration is essential to improve ride comfort on railway vehicles. For this purpose, a primary suspension damping force control system is being developed. This paper describes the composition of the system and reports on the results from vehicle running tests on some Shinkansen lines using actual Shinkansen vehicles fitted with the developed variable primary vertical dampers. The results of these tests demonstrate that this system is effective in reducing vertical vibration acceleration in the first bending mode of the car body and improves ride comfort. In addition, a progress report is also given on its ongoing development. Source

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