| 摘要 |
<p>An arm (11) for a hydraulic excavator (1) is formed as a box-type structure surrounded by left and right side plates (12, 13), a top plate (14), a bottom plate (15), and a thick rear plate (16). An upper end (16A) of the thick rear plate (16) is caused to protrude further upwards than an outside surface (14A3) of the top plate (14). An upper end (22B) of a pair of arm cylinder brackets (22) joined to an outside surface (16C) of the thick rear plate (16) is arranged higher than the outside surface (14A3) of the rear thick top plate (14A) and lower than the upper end (16A) of the thick rear plate (16). As a result, each arm cylinder bracket (22) can secure a large bonding surface area with the thick rear plate (16) and increase bonding strength.</p> |
