LTZC Manufactures Bearings for Mining Shield Machines

I. What Are Tunnel Boring Machine Bearings?

The Tunnel Boring Machine (TBM) is one of the most critical pieces of heavy equipment in underground tunnel construction, widely utilized in subway, railway, water conservancy, municipal, and mining projects. The slewing bearings used in TBMs are typically large-diameter or extra-heavy-duty bearings, serving the dual functions of providing rotational support and transmitting loads for the entire machine.

Structurally, TBM bearings generally fall into the category of heavy-duty turntable bearings, with diameters ranging from several meters to over ten meters. They primarily consist of an inner ring, an outer ring, rolling elements (balls or rollers), cages, sealing devices, and gear rings. Depending on specific operating conditions and requirements, they can be designed with single-row ball, double-row ball, triple-row roller, or cross-roller configurations.

1. Working Principle

The core function of a TBM bearing is to facilitate the stable rotation of the cutterhead, thereby enabling the tunnel excavation process. The TBM slewing bearing must withstand immense axial forces, radial forces, and overturning moments generated by the cutterhead, while ensuring that the cutterhead rotates smoothly and with minimal friction, even under heavy-load conditions.

During the tunneling process, the cutterhead continuously cuts through rock and soil strata, generating complex and highly fluctuating loads. Consequently, the bearing must possess not only a high load-carrying capacity but also exceptional resistance to impact and fatigue.

2. Operating Characteristics of TBM Bearings

High Loads: Capable of withstanding combined loads reaching thousands of tons.

Low Speed, Heavy Load: Rotational speeds are typically low, yet the applied loads are extremely high.

Frequent Impact and Vibration: Irregularities in rock strata result in significant impact loads.

Harsh Environments: Severe exposure to corrosive elements such as mud, water, and dust.

Difficult Maintenance: The cost of replacement after installation is prohibitively high.

Therefore, the design and manufacturing of TBM bearings must adhere to exceptionally rigorous standards of reliability.