| 摘要 |
PURPOSE:To absorb a vibration noise of a cabin frame, by a method wherein stock solution of a foaming synthetic resin is poured into a hollow part of a frame member, and is expanded for curing. CONSTITUTION:A pouring port 19 is bored in an upper part 13a of a front ceiling frame 13, and stock solution of a foaming synthetic resin 20 is poured into a hollow part 13b through the pouring hole 19. A reinforcing material 21 is welded at the upper part 13a of the frame 13 in a manner to cover the pouring port 19. Only air of bubbles in the foaming synthetic resin remains in a cavity in the hollow part. As a result, when vibration of an engine 22 and a mission case 23 is transferred to a cabin frame through a frame 3, a vibration noise is caused not to reflect in the cavity. This prevents the production of echo sound, and the reduction in the number of resonance vibrations prevents the generation of a loud chattering. |
