PROBLEM TO BE SOLVED: To enable replacement of a spring arranged on the upper end part side and modification of a downward urging force for the spring to move a king pin shaft vertically according to a change of the working condition, through a simple configuration and a simple operation.SOLUTION: In a vehicle body 4 provided with travel units 1 and 2, a travel power transmission shaft 6 is arranged in a vertically freely slidable way in a travel power transmission case 5 transmitting driving force to the travel units 1 and 2, a boss 7 including the travel power transmission shaft 6 in a bearing inclusion form. In the upper end part of the boss 7, there is formed an upper chamber 9 which surrounds the upper end part of the travel power transmission shaft 6 and the upper end part of a bearing member 8. In the upper chamber 9, there are included a spring receiving member 65 arranged in a freely removable and vertically freely movable way on the travel power transmission shaft 6 and an upper sprint 10 pressing the spring receiving member 65. In the upper part of the upper chamber 9, a lid material 16 is provided removably.COPYRIGHT: (C)2015,JPO&INPIT【課題】 キングピン軸を作業条件の変化に対応して上下動させるべく、上端部側に設けるスプリングを交換したり、スプリングの下方への付勢力を変更することを、簡単な構成及び操作で行えるようにすることを目的とする。【解決手段】 走行装置1,2を設けた車体4において、走行装置1,2に駆動力を伝動する走行伝動ケース5に走行伝動軸6を上下摺動自在に設け、走行伝動軸6を軸受け内装するボス7を設け、ボス7の上端部には、走行伝動軸6の上端部及び軸受部材8の上端部を囲う上部室9を形成し、上部室9には、走行伝動軸6に着脱自在且つ上下動自在に設けるスプリング受け部材65と、スプリング受け部材65を押圧する上部スプリング10を内装すると共に、上側部に蓋部材16を着脱に設けて構成する。【選択図】 図6
