Mar 1, 2021



Tunnel-boring machine (TBM) projects realize productivity, performance and safety goals with Poclain Hydraulics direct drive solutions. Number one hydraulic motor supplier for TBMs in Japan, Poclain Hydraulics has a long record of delivering robust direct drive motors and heavy-duty radial piston pumps for TBMs in Europe, Asia, and USA.

A worldwide integration and technical support network alongside Poclain Hydraulics’ low maintenance components deliver reliable performance to boost uptime for TBM applications. EPB, slurry, hard rock, pipe jacking and multimode, Poclain Hydraulics solutions address all types of TBMs from <1m up to 17m diameter and their functions:

  • Cutterhead
  • Screw conveyor/auger
  • Thrust cylinders
  • Erectors
  • Mixer
  • Conveyors
  • Shotcrete Arms
  • Other auxiliary functions



Tunnel Boring Machine Diagram 

1) Cutterhead

Meeting efficiency and performance design criteria for the high torque cutterhead drive is critical to maintaining project schedules. The cutter drive affects machine assembly, safety and reliability.

Poclain Hydraulics delivers on precision and strength. Achieve a tight steering radius with highly compact motors to help your machine dig complex sharp curves. 

Our reinforced, heavy-duty bearings are specially designed to help TBM applications withstand shock loads and perform consistently.

Two different motor ranges meet the demands of various TBM cutter head sizes :

  • MS 50 (6 l per rev) to MS 125 (15 l per rev), shaft output as well as smaller sizes for pipe jacking options
  • MI 250 (30 l per rev) with hollow shaft

MS and MI motors in a closed loop system reduce system components (gearboxes, water cooling systems), dimensions and potential failure points, for clear advantages in terms of integration (weight and length), synchronization and safety compared to electric motors.


  • Multiple speeds: 1C, 2C
  • Reinforced bearing and sealing
  • Permanent rotation synchronization and outstanding torque with direct drive

2) Screw conveyor/auger

For maintaining the constant balance pressure of EPB type machines as well as providing effective removal of the excavated material, the motor needs to meet high productivity and reliability constraints. Poclain Hydraulics’ MS motors from MSE02 – MS125 make that possible for screw conveyors in TBMs up to 17m as well as for augers in pipe jacking TBMs


  • Direct drive, end of the screw installation
  • Reinforced bearing and sealing
  • Compact envelope that helps optimize screw conveyor integration and set-up

3) Thrust-cylinders

To advance the TBM forward with accurate and synchronized movement, Poclain PL pumps (open-loop, fixed displacement) offer optimal cylinder synchronization with a compact and robust design for TBMs


  • Heavy duty with radial piston technology (operating pressure 350bar, maximum pressure 450 bar)
  • Fixed displacement (17.5l ~ 74l) with two to six independent outlets providing the same flow

4) Erector

Reinforcing the tunnel walls demands a high level of precision and security. Poclain hydraulics modular MS motors’ modularity enable them to meet the needs of TBMs from EPB to shield-slurry and multi mode types.

MS motors from MS02 to MS83 offer the features necessary to meet support erector functions :            

  • Parking brake : -T42(min brake torque 25000 Nm), -T50( 30000 Nm), -T83(42000 Nm)
  • Flanged counterbalance valve for optimal segment positioning
  • High starting torque and starting efficiency
  • Low inertia equating to high precision

Poclain also supports additional auxiliary functions:


Ensuring the waste soil extracted is the proper consistency means addressing shock loads and pressure peaks. MS motors in MS08 to MS50 sizes help TBMs achieve optimal soil paste consistency for effective evacuation of excavated materials.


  • High output torque
  • Reinforced bearing and sealing
  • Steady motion at low speeds (min 1 rpm)


Removal of overburden or spoil demands efficient and continuous work from the belt drives. MS or motors from sizes MS08 to MS18 deliver low maintenance, compact and robust solutions to support this function for TBMs


  • Direct drive
  • Minimize downtime

Shotcrete arms

Like the erectors, the shotcrete arms need a high level of precision to ensure the concrete pistol maintains the right position. MS motors from MS05 to MS11 support this function in hard rock TBMs :


  • Parking brake: -T42(min brake torque 25000 Nm), -T50( 30000 Nm), -T83(42000 Nm)
  • Flanged counterbalance valve for precise positioning



For more information or to discuss your particular project, contact Thierry Delage Poclain Market Manager Thierry.delage@poclain.com

Hear from CREG about their experience with Poclain Hydraulics as a TBM customer.