TBM disc cutter is a kind of digging tool for breaking hard rock. It is installed on the head of large-scale trenchless construction equipment such as shield, TBM and pipe jacking. Its function is to cut and peel off the rock from the face. It is widely used in subway tunnel, railway tunnel, diversion tunnel and urban underground pipe network construction.

TBM disc cutter is a kind of tool which can change the cutter ring. It can be divided into single edge, double edge and multi edge. It is usually installed on the cutter head of shield machine in radial or spiral distribution. The shield machine is driven forward under the pressure of the jack. At the same time, the cutter head of the shield machine rotates. The cutter installed on the cutter head of the shield machine rotates with the cutter head and rotates under the friction and pressure, so that the cutting edge of the cutter ring can produce rolling cutting effect on the rock surface.

The working principle of rock breaking by disc cutter can be understood as follows: when driving, the disc cutter first extrudes a groove in the rock, and then generates initial tensile failure cracks around the groove. With the continuous penetration of the cutter, the wedge-shaped face of the cutter ring acts as shear failure to the rock on both sides of the cutter ring, and the initial tensile failure crack will continuously and rapidly expand along the tangent direction of the rock under the shear force The rock cracks between the adjacent cutting tools will affect each other, and further tensile failure will be produced, which will make the rock ridge between the adjacent cutting grooves produce large rock block spalling off under this tensile failure.

The TBM disc cutter installed on the cutter head is pressed tightly on the rock surface under the action of Jack. With the rotation of the cutter head, the TBM disc cutter rotates around the central axis of the cutter head on the one hand, and rotates around its own axis on the other hand. Under the action of thrust and torque of TBM disc cutter, a series of concentric grooves are cut on the face of face. When the thrust exceeds the strength of the rock, the rock under the tip of the disc cutter is directly broken, and the tip penetrates into the rock, forming a crushing area and radial cracks; when the distance s of the hobs meets certain conditions, the cracks in the rock between the adjacent hobs extend and connect with each other, forming rock fragments and collapsing, and the disc cutter completes a rock breaking process.

In addition to bearing the circumferential positive pressure of the cutter ring, the TBM disc cutter is also affected by the tangential friction force of the cutter ring and the alternating stress in the lateral direction. The stress is complex and the working environment is bad. The formation and spalling rock have grinding and erosion effect on the cutter ring and cutter body, which is easy to cause the early failure of the tool. It puts forward high requirements for the rock breaking effect of the tool, the tolerance of the tool to the working environment and the stability of the tool quality. The quality of cutting tool directly determines the quality, cost, safety and efficiency of the project, which is one of the core technologies in the construction of tunnel and subway shield method.

At the construction site, the assembly and disassembly of TBM disc cutter is usually carried out in the small tool maintenance workshop provided with the machine. In order to save the transportation time, the tool workshop is generally arranged at the side near the entrance. The cutter ring and cutter body, bearing inner ring and spindle are interference fit, and their assembly and disassembly need special process.

Assemble

1. The cutter ring and bearing inner ring are heated separately in advance to make the inner circle of the parts expand and expand. After the parts are cooled, the expected interference fit can be achieved (see the product manual for specific assembly requirements). For example: when assembling the 19in TBM disc cutter of Robbins Full Face Rock Road header, the cutter ring is heated to 160 ℃ in advance and then installed into the cutter body; when the bearing inner ring is heated to 120 ℃, the mandrel can be reached; after the parts are cooled, the expected interference fit requirements can be achieved.

2. The installation of the spacer ring is determined according to the distance between the small end faces of the bearing inner ring of two tapered roller bearings in the cutter body. The width of the spacer ring needs to be ground on site, and the width tolerance should be less than the measured width. For example: the installation width of the inner isolating ring of the 17 inch disc cutter of the wilt Full Face Rock Road header should be less than 0.2mm of the measured value. After assembly, the bearing should be in the pre tightening state, and the detection tool torque within the range of 60-80n · m is qualified.

3. 17 inch TBM disc cutter and screws (No. 12 in Fig. 2-20, FIG. 2-21 and Fig. 2-22) of wilt Full Face Rock TBM are bonded with sealant (cascok No. 119) during assembly; 80% lubricating oil (model 320) with 1% odor agent (molyvan, 1.5L Mystik JT-7) is injected into the inner cavity of the cutter body Sae90-140, 1% molyvan). When the bearing and seal are damaged and the lubricating oil overflows, the irritating odor can be smelled, warning that the tool is damaged and can be replaced in time.

Disassemble 

When disassembling the cutter ring and bearing, the worn and scrapped cutter ring is cut off and removed with grinding wheel, and the bearing inner ring is pressed out by a special bench press.