North Tianjin Shandong a little more, the better there may be Longyuan hydraulic, long Yu Lihua and so on.
Other areas are new Kui hydraulic, Xiamen Yinhua and so on.
Sany's called Loudi City, Zhongxing Hydraulic Parts Co. Ltd. under Zoomlion called Hunan Tetra Hydraulics Co. Xugong's called Xugong hydraulic parts. The above three look at the size of its parent company is not small.
In the end, the largest, there is no standard, so can not speak.