shield_tunnel_engineering

Bearing Solutions for Shield Tunnel Engineering | AOKAI

Welcome to AOKAI, your trusted partner for advanced bearing solutions in shield tunnel engineering.

shield_tunnel_engineering
Challenge

Overcoming the Underground Challenge

Shield tunnel engineering operates in the most unforgiving environments on earth, where bearing failure is not an option.

Tunnel Boring Machines (TBMs) are the behemoths of modern infrastructure, tasked with excavating through solid rock, abrasive sand, and high-pressure sludge. In shield tunnel engineering, the bearings are subjected to immense multi-axis loads, severe vibrations, and constant exposure to corrosive groundwater and mud. A single bearing failure deep underground can lead to catastrophic project delays and astronomical replacement costs.

To overcome these challenges, bearings used in TBMs must possess exceptional axial and radial load-bearing capacities, unparalleled shock resistance, and robust sealing mechanisms. As a specialized bearing manufacturer, we understand that the success of a tunneling project hinges on the reliability of its rotating core. Our bearings are meticulously engineered to ensure zero downtime, providing continuous excavation power from the launch shaft to the breakthrough.

Solutions

Comprehensive Bearing Solutions for TBMs

From the massive cutterhead to the intricate erector systems, we provide a complete suite of bearing solutions tailored for the specific kinematics of shield tunneling.

The cutterhead main bearing is the most critical component of a TBM. Our main bearings feature a specialized three-row cylindrical roller slewing ring design, manufactured from high-purity, vacuum-degassed forging steel. Through advanced induction hardening techniques, we ensure optimal raceway hardness while maintaining a tough, shock-absorbing core. Equipped with integrated gear rings and heavy-duty multi-lip sealing systems, these bearings withstand extreme eccentric loads and prevent the ingress of abrasive slurry, guaranteeing a lifespan that outlasts the tunneling drive.

Behind the cutterhead, the segment erector is responsible for building the tunnel wall. This requires smooth, highly precise rotation under heavy suspended loads. Our erector bearings are engineered with minimal clearance and high-strength gear teeth to provide precise control and smooth articulation. This ensures that operators can align multi-ton concrete segments safely and efficiently, streamlining the tunnel lining process.

Extracting excavated material (muck) from the pressure chamber requires heavy-duty screw conveyors. The bearings supporting these conveyors face continuous high axial loads and constant exposure to abrasive rock dust. We supply premium spherical roller bearings and thrust bearings with optimized internal geometry and advanced surface treatments, significantly reducing friction and wear to maintain continuous material extraction.

Why Choose Us

Engineered for Excellence: Your Trusted Partner

We combine cutting-edge R&D, rigorous quality control, and deep industry experience to deliver authoritative solutions you can trust.
01

Proven Expertise (Experience & Expertise)

With years of specialized focus on large-scale slewing rings and heavy-duty industrial bearings, our engineering team works directly with TBM designers to customize bearing geometries, load ratings, and gear parameters based on specific project geology (e.g., EPB, Slurry, or Hard Rock TBMs).

02

Uncompromising Quality (Authoritativeness)

Our manufacturing facilities are ISO 9001 and ISO 14001 certified. Every TBM main bearing undergoes stringent 100% Non-Destructive Testing (NDT), including Ultrasonic Testing (UT) and Magnetic Particle Inspection (MT), ensuring absolute structural integrity.

03

Complete Traceability (Trustworthiness)

We believe in total transparency. From raw material sourcing (certified steel mills) to final heat treatment and dimensional inspection, every bearing comes with a comprehensive quality dossier and material certification, giving your procurement and engineering teams absolute peace of mind.

FAQs

Technical Support & FAQs

Explore our technical insights and find out how our bearing solutions integrate into your TBM projects.

Can you customize the main cutterhead bearing for a specific TBM diameter?
Yes. We specialize in custom-engineered slewing bearings. Whether you are building a micro-tunneling machine (MTBM) or a mega-TBM exceeding 15 meters in diameter, our engineering team will design the bearing's load capacity, gear ratio, and dimensions to match your exact technical specifications.

What materials do you use to ensure the longevity of TBM bearings?
We exclusively utilize premium-grade, vacuum-degassed alloy steel (such as 42CrMo4 or 50Mn). The raceways undergo precise CNC induction hardening to achieve a high surface hardness (typically 58-62 HRC) while retaining core toughness to absorb the massive shock loads of rock excavation.

How do your bearings prevent mud and water ingress underground?
Sealing is critical in shield tunnel engineering. Our main bearings are designed to integrate seamlessly with multi-lip, pressurized sealing systems. We also apply specialized anti-corrosion coatings and precise raceway sealing grooves to ensure the bearing remains completely isolated from high-pressure water, mud, and abrasive rock dust.

What is your standard lead time for a custom TBM main bearing?
Given the ultra-large dimensions and complex manufacturing processes (forging, CNC machining, gear cutting, heat treatment), standard lead times range from 3 to 6 months. However, we offer expedited production schedules for urgent infrastructure projects. Please contact our sales engineers for an accurate timeline.
Workshop
CONTACT US
Ready to Drive Your Tunneling Project Forward?
Don't let bearing failure compromise your project timeline. Partner with a manufacturer that understands the extreme demands of shield tunnel engineering. Whether you are designing a new TBM or require a replacement bearing for an existing fleet, our team is ready to provide technical consultation, CAD modeling, and competitive quotes.

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