On May 10, 2020, China Railway Engineering Equipment Group (CREG) showed the first batch of domestic 6-meter shield main bearings. The main bearing is known as the "heart" of shield machine. The shield machine is faced with complex stratum in the process of tunneling. The main bearing needs to bear high-speed rotation, huge load and strong temperature rise. If the main bearing of shield machine breaks down, it is extremely difficult to maintain or replace it on site, or even impossible.
On July 24, 2015, CREP cooperated with 滚球188 , a leading domestic shield machine main bearing enterprise, to carry out research on key technologies of domestic main bearing and industrial tests. Combined with the operating conditions of the main bearing of the shield TBM, the key design, material and heat treatment of the main bearing of the shield, precision machining and detection of the main bearing of the shield are broken through, and two specifications of the main bearing of the 6-7m shield are successfully developed.