With　the　increase　of　passenger　space,　the　installation　space　of　vehicle　brake　system　decreases.　It　is　a　contradiction　between　the　volume　of　the　brake　cylinder　of　urban　rail　transit　vehicles　and　the　braking　force　demand.　Aiming　at　the　design　of　the　brake　cylinder　volume　requirement　of　urban　rail　transit　vehicles,　ARIZ　algorithm　is　used　to　define　the　mini-problem,　which　it　is　necessary　for　the　engineering　system　is　unchanged　while　the　assembly　demand　of　the　brake　cylinder　on　the　bogie　is　retained,　and　the　braking　effect　of　the　braking　system　is　effectively　improved.　Based　on　the　mini-problem,　the　ideal-final　solution　and　physical　contradiction　were　defined,　and　the　expanded　substance　field　resources　were　used　to　solve　the　problem,　in　which　13　high-quality　solutions　are　obtained.　Combining　all　the　innovative　solutions,　a　new　design　method　of　brake　cylinder　system　is　designed　for　gearbox.　Finally,　the　feasibility　of　the　scheme　is　achieved.　©　2023　SPIE.　All　rights　reserved.