Running device for track-laying vehicle

A running device for track-laying vehicle comprising:

• a pair of track frames that is provided at right and left of the track-laying vehicle;
• an idler that is rotatably supported in one end portion of the track frame;
• a sprocket that is rotatably driven in a direction of the other end portion of the track frame so that the track frame, the idler, and the sprocket are provided in a substantial straight line;
• and
• a double-bogie device that includes a set of first and second front-back lower track rollers provided in a lower portion of the track frame,
• wherein a crawler is entrained about the idler, each of the lower track rollers, and the sprocket,
• the double-bogie device includes a first arm whose base end portion is supported by the track frame while freely oscillated and a second arm whose central portion is attached to a leading end portion of the first arm while freely oscillated,
• the first and second lower track rollers are rotatably supported by both end portions of the second arm,
• elastic members are provided in respective opposite surfaces of the first arm and the track frame, and
• a spring constant equalizing unit that equalizes an apparent spring constant of the double-bogie device over a total length in maximum reverse camber of the crawler is provided.