| 摘要 |
PURPOSE:To reduce the pneumatically generated sound level of a pantograph by pneumatically irregularly forming the sectional shape of a member having uniform section and large pneumatically generated sound, thereby suppressing the generation of a Karman vortex occurred at the high speed running time. CONSTITUTION:An air gap 10 is intermittently formed between a slide plat 8' and a slide plate body 9' of a shoe 1' through spacers intermittently disposed between the plate 8' and the body 9' or by providing periodic projections at the side of the body 9', on which the plate 8' is mounted. The height (d) and width (l) of the gap 10 are formed, for example to be 0.1 times and twice of the thickness (a) of the vertical section of the shoe 1', and the air gaps 10 are intermittently formed at an interval of the width (l). Thus, since an air stream disorders the flow of the after stream through the air gap 10 during running, it can prevent the generation of Karman vortex and reduce the pneumatic noise level. |
