Breaking Through The Bottleneck Of Rare Earth Steel, My Country's First Shield Machine Was Successfully Researched And Developed With A Large Diameter Slewing Bearing

The reporter was informed on December 15 that recently, the super large shield machine led by Li Dianzhong and Academician Li Yiyi's team at the Institute of Metal Research of the Chinese Academy of Sciences was successfully researched and developed with a diameter of 8 meters in diameter. The main shaft load is 41 tons, which is currently the first set of shield machines made by the first set of diameter and the largest single-weight shield machine. The main axle will be installed on a large-scale shield machine with a diameter of 16 meters for tunnel engineering mining.

The successful development of the main axle marks integrated technologies such as independent design, material preparation, precision processing, installation, commissioning, and detection evaluation of the spherical items of the shield machine.

The 8 -meter spindle bearing power is equivalent to 2500 adult Asian phenomena weights

The shield machine is a major piece of equipment for infrastructure construction, which carries the heavy responsibility of crossing mountains and crossing the river. my country has realized the localization of the shield machine, but its core component, the main bearing dependent on imports. "my country's high-end bearing market is mainly occupied by foreign brands. It is subject to people in terms of procurement, technology, supply cycle, and price, and urgently needs to open up the" last mile "that can be controlled by autonomous control."

According to Li Dianzhong, the main bearing is the core key component of the shield machine's knife drive system. During the excavation of the shield machine, the main bearing "handheld" blade swived cutting and cutting the palm noodles and providing rotating support for the knife plate. The spindle with a diameter of 8 meters is equivalent to the round table where about 50 people are sitting. The maximum axial force carried during the operation reaches 105 thousand cows. "The gravity of 1,000 cows is about 0.1 tons of objects. If the weight of an adult Asian elephant is calculated at 4 tons, this is equivalent to the axial direction of 2,500 Asian elephant gravity."

In order to ensure the high load capacity and high reliability of the main bearing, the bearing steel that is especially required to create the main bearing must be high and pure, high-quality, high and strong, and wear-resistant. At the same time, A high request was made. In the process of excavation, large shield machines can only move forward and cannot retreat. Once the main bearing fails, it will cause serious losses.

The main bearings of the 3m shield machine have been used in the construction of the Shenyang Metro

During the team checkout, researcher Hu Xiaoqiang, chief of the shield machine's main bearing technical chief, successfully overcome the high-precision processing and accuracy maintenance problems of the spindle bearing. They found in the development that due to foreign technology restrictions, my country's imported equipment can only reach the second level, and the first-level precision processing cannot be achieved. The team combined with enterprises to integrate intelligence and develop a first-class roller with a diameter of more than 100 mm, which made my country's bearing industry break through the first-class large roller precision processing technology.

At present, the 3m shield machine's main bearing has passed the acceptance of construction user inspection on November 16, 2021, and was launched on the Shenyang Metro on April 20, 2022.