TBM cutter seat force detection sensor

Abstract

The utility model relates to a shield machine cutter seat force detection sensor, including three groups of sensing elasticity parts that install respectively in the cutter seat sides of shield machine cutter disc center area, transition area cutter seat sides and edge area cutter seat sides, sensing elasticity part includes elastomer, circuit board and cable, a plurality of groups of strain gauges are installed on the elastomer four around edges, the strain gauge is connected with circuit board through wire, and the corresponding strain gauge on each elastomer respectively constitutes independent wheatstone bridge on the circuit board, can detect axial reaction force, radial cutting force, radial extrusion force simultaneously through the utility model, solves the limitation of traditional single area detection, and cutter disc overload damage rate reduces.

Description

Technical Field

[0001] This utility model relates to the technical field of tunnel boring machine testing equipment, and in particular to a tunnel boring machine cutterhead force detection sensor. Background Technology

[0002] As the core equipment for underground tunnel construction, tunnel boring machines (TBMs) are widely used in underground tunnel construction for projects such as transportation, mining, and water conservancy due to their advantages of high automation, rapid excavation, safe operation, and minimal impact on the surface environment. With the development of information and automatic control technologies, TBMs are iterating towards multi-functionality and intelligence to adapt to the needs of complex geological conditions.

[0003] The cutterhead is a key core component of a tunnel boring machine (TBM), located at the front end of the machine. It serves as the mounting carrier for various cutting tools and bears the important functions of breaking up and stripping soil and rock at the tunnel face and supporting the tunnel face. However, during underground excavation, TBMs face complex and varied geological environments, including silt, clay, sand, soft rock, and hard rock. This results in complex stress states on the cutterhead and a harsh working environment, making the cutterhead a key component requiring inspection and maintenance. Its stress state is closely related to the TBM's excavation efficiency, service life, and cutting tool maintenance costs. Furthermore, it is difficult to detect the magnitude of the force exerted on the cutterhead by the geological formation, making it difficult to determine whether the cutterhead can excavate safely during the tunneling process. Encountering complex geological formations such as hard rock can easily damage the cutterhead, and it is also impossible to dynamically adjust the excavation frequency and speed according to actual working conditions. Utility Model Content

[0004] This utility model addresses the shortcomings of existing technologies by providing a force detection sensor for the cutterhead bearing of a tunnel boring machine. The specific technical solution is as follows:

[0005] The shield machine cutterhead force detection sensor includes three sets of sensing elastic parts installed on the sides of the cutterhead in the central area, the transition area, and the edge area of ​​the shield machine cutterhead, respectively. Each sensing elastic part includes an elastic body, a circuit board, and cables. Multiple strain gauges are installed around the periphery of the elastic body. The strain gauges are connected to the circuit board through wires. The strain gauges on each set of the elastic body form an independent Wheatstone bridge on the circuit board.

[0006] Preferably, the elastomer has at least two mounting slots on both its front and back sides, and one strain gauge is mounted in one of the mounting slots.

[0007] Preferably, one side of the elastomer is provided with an inlet hole, and a waterproof connector is connected to the inlet hole. A through hole is provided between two sets of mounting grooves facing each other on the front and back of the elastomer. A connecting hole is provided between two oblique mounting grooves on the front and back of the elastomer. The strain gauge wire passes through the through hole, the connecting hole, and the through hole and is connected to the waterproof connector. The through hole, the connecting hole, and the through hole are filled with a sealant layer, which is an epoxy resin sealant.

[0008] Preferably, the circuit board integrates an adapter transmitter, which is used to convert the differential pressure signal output by the Wheatstone bridge into a 4-20mA analog signal. The cable is connected to the circuit board through a waterproof connector for transmitting the 4-20mA analog signal.

[0009] Preferably, one of the elastomers is fixed to the non-side of the cutterhead central area of ​​the tunnel boring machine (TBM) cutterhead roller seat by bolts and is in close contact with the force-bearing surface of the cutterhead central area of ​​the TBM cutterhead roller seat. When the central cutterhead of the TBM cuts the stratum, the reaction force of the stratum on the cutterhead is transmitted to the elastomer, causing the elastomer to deform so that it can be captured by the strain gauge.

[0010] Preferably, one of the elastomers is fixed to the side of the transition zone hob holder, perpendicular to the force direction of the transition zone hob holder, so as to capture the radial cutting force of the transition zone hob through a strain gauge.

[0011] Preferably, one of the elastomers is fixed to the outer end face of the edge zone cutter holder by bolts, and the thickness of the elastomer is greater than the side protrusion of the edge zone cutter holder, so as to withstand the radial extrusion force of the formation by capturing the edge zone cutter.

[0012] Preferably, one end of the cable is connected to the circuit board via a waterproof connector, and the other end of the cable is connected to the tunnel boring machine controller.

[0013] The beneficial effects of this utility model are:

[0014] 1. Full-area stress detection with no blind spots: The three sets of elastic sensors are adapted to the center area, transition area and edge area of ​​the cutterhead, respectively, and can simultaneously detect axial reaction force, radial cutting force and radial extrusion force, solving the limitations of traditional single-area detection; the detection data provides a basis for judging the formation characteristics (such as hard rock location, sand layer distribution) and reduces the overload damage rate of the cutterhead.

[0015] 2. The fully sealed inlet hole, through hole, and installation gap make it suitable for damp underground environments with lots of mud; the overall lifespan of the sensor is extended, reducing downtime for replacement and lowering maintenance costs. Attached Figure Description

[0016] Figure 1This is a top view of the overall structure of this utility model;

[0017] Figure 2 This is a front view of the overall structure of this utility model.

[0018] Reference numerals: 1. Elastomer; 100. Mounting groove; 2. Strain gauge; 31. Inlet hole; 32. Through hole; 33. Connecting hole; 4. Mounting hole; 5. Waterproof connector. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0020] Example

[0021] For the shield machine cutterhead force detection sensor, please refer to... Figures 1-2 It includes three sets of sensing elastic parts (corresponding to the center area, transition area, and edge area of ​​the cutter head), signal processing components, and waterproof sealing components. Each component works in coordination with the signal link through structural design. The sensing elastic parts (the core of force detection, with three sets having the same structure but different installation positions) each use an elastomer 1 as a carrier and integrates a strain gauge 2 to achieve accurate capture of the force on the hobbing holder in different areas.

[0022] The elastomer 1 has mounting grooves 100 machined on both the front and back sides for precise fixing of the strain gauge 2; mounting holes 4 are opened at the four corners of the elastomer 1, which are connected to the hobbing seat by high-strength bolts.

[0023] The central region elastic body 1 is fixed to the non-side of the central region cutter holder by bolts (closely fitting with the force-bearing surface of the cutter holder, with a fitting gap ≤0.05mm) to capture the axial reaction force (≤500kN) of the cutter cutting the formation.

[0024] The transition zone elastic body 1 is fixed to the side of the transition zone hob holder (perpendicular to the direction of force on the hob) to capture the radial cutting force;

[0025] The edge region elastomer 1 is fixed to the outer end face of the edge region cutter holder, and the thickness of the elastomer 1 is greater than the side protrusion of the cutter holder (exceeding by 5mm) to avoid the protrusion blocking the force and to capture the radial extrusion force of the formation on the edge cutter.

[0026] The elastomer 1 has high elastic recovery and generates small deformations synchronously when the hob holder is subjected to force. The deformation transmission efficiency is ≥95%, providing a precise force-deformation conversion carrier for the strain gauge 2.

[0027] Strain gauge 2 is a BX120-3AA type metal foil strain gauge 2. One strain gauge 2 is fixed in each mounting groove 100 of each group of elastic bodies 1. The strain gauge 2 is fixed in the mounting groove 100 with special adhesive (CY-121 type strain adhesive). After curing, it is treated with moisture protection (spraying 0 silicone rubber).

[0028] The wires (copper core PTFE insulated wires) of strain gauge 2 converge at the inlet hole 31 through the through hole 32 and the connecting hole 33, and are connected to the circuit board. Strain gauge 2 forms an independent Wheatstone bridge on the circuit board. Using the bridge compensation principle (temperature compensation, nonlinear compensation), the deformation of the elastic body 1 is converted into a differential pressure signal (sensitivity 1mV / V, error ≤0.5%FS), which greatly improves the detection accuracy.

[0029] The signal processing component converts the weak signal output by strain gauge 2 into a stable standard signal, enabling real-time communication with the tunnel boring machine controller. This includes a circuit board made of FR-4 epoxy resin copper-clad laminate, integrating a converter transmitter (model AD694, accuracy 0.1%FS), a temperature compensation chip (LM35, measurement range 0-100℃), and an electromagnetic interference suppression circuit (common-mode inductor + TVS diode). The circuit board is fixed to a groove on the side of the elastomer 1 using countersunk bolts (M3) (groove depth 5mm to avoid bolt protrusion interference).

[0030] Signal processing logic: The mV-level differential pressure signal output by the Wheatstone bridge (e.g., 500kN force corresponds to 5mV / V) is transmitted to the transfer transmitter, which amplifies and converts it into a 4-20mA standard analog signal (4mA corresponds to 0kN, 20mA corresponds to the rated force of elastic body 1; central zone: 500kN→20mA; transition zone: 300kN→20mA; edge zone: 400kN→20mA); the temperature compensation chip monitors the ambient temperature in real time and dynamically adjusts the signal through the transmitter to ensure that the temperature drift is ≤0.01%FS / ℃; the electromagnetic interference suppression circuit can resist the 1000V / m electromagnetic radiation generated by the cutterhead motor, improving the signal anti-interference capability by 80%; the signal conversion delay is ≤10ms and the linearity error is ≤0.2%FS, providing real-time and stable force data for the tunnel boring machine controller and supporting the dynamic adjustment of tunneling parameters.

[0031] The cable uses a polyurethane sheathed shielded cable (model PUYVFR-4×0.75, 4 cores, each core conductor is 19 strands of 0.2mm copper wire, oil-resistant, hydrolysis-resistant, and wear-resistant); the cable outer diameter is 8mm, the length is adapted according to the cutterhead radius, and it has an internal galvanized steel wire reinforcing core to prevent the cable from being pulled and broken when the tunnel boring machine rotates;

[0032] One end of the cable is connected to the signal output terminal of the circuit board via a waterproof connector (sealed with epoxy resin after soldering), and the other end is connected to the tunnel boring machine controller via an aviation plug (model WEIPU SF12-4 core, protection level IP68). The cable transmits 4-20mA analog signals, and the signal attenuation is ≤1% when the transmission distance is ≤100m, ensuring data transmission without distortion.

[0033] The inlet hole 31 is located on the side of the elastomer 1, and the inner wall is machined with an M16×1.5 thread; the waterproof connector is made of brass (chrome plated), model PG9, with a sealing rating of IP68, and is compatible with an outer diameter of 8mm for cables; the waterproof connector is connected to the inlet hole 31 by threads, and the connector is equipped with a double sealing ring (nitrile rubber, Shore hardness 70±5).

[0034] The waterproof connector mates with the inlet hole 31 to achieve a sealed connection between the cable and the elastomer 1, preventing groundwater and mud from entering through the inlet hole 31; at the same time, the connector can rotate 360° to avoid torsional damage to the cable caused by the rotation of the cutter head.

[0035] The through hole 32, the connecting hole 33, and the sealant layer are provided. The through hole 32 is formed between the mounting grooves 100 facing each other on the front and back sides of the elastomer 1, and is used for the strain gauge 2 wires to pass through to the back side. The connecting hole 33 is formed between the oblique mounting grooves 100 on the front and back sides, and is used for the strain gauge 2 wires to converge in different mounting grooves 100. The through hole 32 and the connecting hole 33 are filled with epoxy resin sealant, and the sealant filling height is flush with the hole opening. The surface is polished smooth.

[0036] The sealant layer completely seals the gaps between the wires, achieving an IP68 waterproof rating. It also secures the wires in place, preventing them from falling off or wearing out due to tunnel boring machine vibration. The epoxy resin material has excellent chemical corrosion resistance, resisting the erosion of acidic and alkaline substances (pH 4-10) in groundwater, ensuring long-term stable insulation performance of the wires.

[0037] Apply silicone sealant (Dow Corning 737, temperature resistance -60~200℃) to the mating surface of elastomer 1 and cutter seat to further prevent slurry from entering through the installation gap;

[0038] The groove containing the circuit board is filled with polyurethane potting compound (model PU-610, thermal conductivity 0.8W / (m·K)). The potting compound completely covers the circuit board and solder joints, achieving triple protection of waterproofing, vibration resistance, and thermal conductivity. The circuit board's operating temperature is stabilized between -10~60℃, and the failure rate is reduced by 90%.

[0039] Working principle

[0040] 1. Force transmission and deformation conversion: When the tunnel boring machine is excavating, the cutter cuts the strata and generates reaction force / compression force, which is transmitted to the elastic body 1 through the cutter block. The elastic body 1 undergoes a small deformation, which causes the sensitive grid of the surface strain gauge 2 to deform, causing the resistance value of the strain gauge 2 to change (ΔR / R is proportional to the deformation).

[0041] 2. Signal Conversion and Compensation: The Wheatstone bridge composed of strain gauges 2 converts the resistance change into a mV-level differential pressure signal; the converter on the circuit board amplifies the differential pressure signal and converts it into a 4-20mA analog signal; the temperature compensation chip adjusts the signal in real time to offset the influence of temperature on the detection accuracy; the anti-interference circuit suppresses electromagnetic radiation to ensure signal stability.

[0042] 3. Data transmission and application: The 4-20mA signal is transmitted to the tunnel boring machine controller through a shielded cable. The controller judges the stress state of each area of ​​the cutterhead based on the force data of the three sets of sensors. If the force in the central area exceeds 400kN (80% of the rated value), the cutterhead speed is automatically reduced (from 2.5r / min to 1.8r / min).

[0043] If the extrusion pressure in the edge area exceeds 320kN, adjust the tunnel boring machine thrust (from 3000kN to 2500kN) to avoid overloading the edge cutterhead;

[0044] At the same time, the controller records the stress data and generates a stress distribution map of the cutterhead, providing a basis for geological analysis and tool maintenance (e.g., areas with abnormal stress correspond to hard rock formations, where tool wear needs to be checked).

[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A force detection sensor for the cutterhead seat of a tunnel boring machine, characterized in that, It includes three sets of sensing elastic units installed on the sides of the cutterhead in the central area, the transition area, and the edge area of ​​the tunnel boring machine cutterhead, respectively. Each sensing elastic unit includes an elastic body, a circuit board, and cables. Multiple strain gauges are installed around the perimeter of the elastic body. The strain gauges are connected to the circuit board through wires. The strain gauges on each set of the elastic body form an independent Wheatstone bridge on the circuit board.

2. The shield machine cutterhead force detection sensor according to claim 1, characterized in that: The elastomer has at least two mounting slots on both its front and back sides, and one strain gauge is mounted in one of the mounting slots.

3. The shield machine cutterhead force detection sensor according to claim 2, characterized in that: One side of the elastomer is provided with an inlet hole, and a waterproof connector is connected to the inlet hole. A through hole is provided between two sets of mounting grooves facing each other on the front and back of the elastomer. A connecting hole is provided between two oblique mounting grooves on the front and back of the elastomer. The strain gauge wire passes through the through hole, the connecting hole, and the through hole and is connected to the waterproof connector. The through hole, the connecting hole, and the through hole are filled with a sealant layer, which is an epoxy resin sealant.

4. The shield machine cutterhead force detection sensor according to claim 3, characterized in that: The circuit board integrates an adapter transmitter, which is used to convert the differential pressure signal output by the Wheatstone bridge into a 4-20mA analog signal. The cable is connected to the circuit board through a waterproof connector for transmitting the 4-20mA analog signal.

5. The shield machine cutterhead force detection sensor according to claim 4, characterized in that: One of the elastomers is fixed to the non-side of the cutterhead central area of ​​the tunnel boring machine (TBM) cutterhead roller seat by bolts and is in close contact with the force-bearing surface of the cutterhead central area of ​​the TBM cutterhead roller seat. When the central cutterhead of the TBM cuts the stratum, the reaction force of the stratum on the cutterhead is transmitted to the elastomer, causing the elastomer to deform so that it can be captured by the strain gauge.

6. The shield machine cutterhead force detection sensor according to claim 5, characterized in that: One of the elastomers is fixed to the side of the transition zone hob holder, perpendicular to the force direction of the transition zone hob holder, so as to capture the radial cutting force of the transition zone hob through a strain gauge.

7. The shield machine cutterhead force detection sensor according to claim 6, characterized in that: One of the elastomers is bolted to the outer end face of the edge zone cutter holder, and the thickness of the elastomer is greater than the side protrusion of the edge zone cutter holder, so as to withstand the radial compressive force of the formation by capturing the edge zone cutter.

8. The shield machine cutterhead force detection sensor according to claim 7, characterized in that: One end of the cable is connected to the circuit board via a waterproof connector, and the other end of the cable is connected to the tunnel boring machine controller.

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