Abstract:

Based on the working area of the hydraulic excavator, the effect of the size change of the working mechanism on digging range and the working performance indices is studied. According to the performance requirements, the optimization design strategy of the working mechanism size is provided. Considering the typical conditions during the excavating operation such as arm digging and bucket digging, the corresponding excavating trajectory envelope curves are drawn by the working device motion analysis software. The size change influence of the boom, arm, and bucket of the working mechanism on the digging performance indices of the whole machine is analyzed. The dynamics analysis is carried out on the working mechanism, and the complex digging force is optimized. The results show that when the boom size increases, the maximum digging depth and the digging reach are increased by 5.56% and 13.31%, respectively, and the maximum cutting height and the dumping height are increased by 51.36% and 53.87%, respectively. When the arm size is increased, the overall change rate of the 4 main working dimensions is less than 5%, but the increase rate is relatively low, and the relative increase rate of the cutting height is decreased. As the bucket size is increased, the maximum digging depth is increased by 2.7% and the relative increase rate is homogeneous. The overall change rate of the maximum cutting height, digging reach are about 1.3%, moreover, the maximum dumping height is decreased. After optimization, the larger digging force is 532.16 kN, and compared with the arm digging and bucket digging has large improvement, and the path of the main working conditions is given.

Key words: mechanism size, working device, working performance, hydraulic excavator