Improvement in Durability of Journal Plane Bearings

Engineer, Metallic Materials Group
Materials Technology Development Division
Technological Development Department, RTRI

Tetsuya NITTA
Transport and Technology Dept.
Railway Operations Headquarters,
Japan Freight Railway Company

Engineer, Strength Evaluation and Inspection
Vehicle Technology Development Division
Technological Development Department, RTRI

Takehiko KIGAWA
Chief-Engineer, Railroad Vehicle Group,
Roller Bearing Technology Dept.
Bearing Engineering Center, NSK Ltd.

Lead base white metals have been used for journal plane bearing of freight cars for a long time in Japan. Lately, an alteration of base material from lead to tin was discussed to improve working environments. Specimens and full-size bearings were tested to compare the scuffing resistance of these metal materials including running performance tests by freight cars. WJ-2, one of the tin base white metals, has a better scuffing resistance than lead base white metals WJ-7. The scuffing load is reduced remarkably, however, by an increased roughness and/or waviness of journal surface. Therefore, scuffing resistance of journal plane bearings is improved noticeably by a combination of WJ-2 material and properly machined and finished journal.