A double-cylinder series detection system for detecting the excavation diameter of a shield machine cutter head

Abstract

The application provides a double-oil-cylinder series detection system for detecting the excavation diameter of a cutter head of a shield machine, which comprises a first oil cylinder arranged on the cutter head, a second oil cylinder arranged on a support of the shield machine and located behind the cutter head, an oil circuit for feeding and returning oil of the first and second oil cylinders, a sensor for detecting the extension and retraction distance of a top rod of the second oil cylinder, and a control center connected with the sensor, wherein the top rod of the first oil cylinder can extend or retract from the outer circumferential surface of the cutter head along the radial direction of the cutter head, the oil circuit comprises a feeding pipe connected with an oil source and an oil inlet of the first oil cylinder, a connecting pipe connected with an oil return port of the first oil cylinder and an oil inlet of the second oil cylinder, and a return pipe connected with an oil return port of the second oil cylinder and an oil return tank, the synchronous extension and retraction of the top rod of the second oil cylinder and the top rod of the first oil cylinder is realized, the detection value of the sensor received by the control center can be conveniently converted into the excavation diameter of the cutter head of the shield machine, the accuracy and reliability of the detection result are better, and the excavation diameter of the cutter head can be detected during tunneling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield technology, and particularly relates to a double-oil-cylinder series detection system for detecting the excavation diameter of a cutter head of a shield machine. BACKGROUND

[0002] During tunneling, the cutter gradually wears, resulting in a smaller tunnel diameter. Meanwhile, the external stratum or mountain body of the tunnel shrinks inward, especially when the shield machine is stationary for a long time. The inward shrinkage is particularly obvious. A tunnel that is too small can cause the shield to be stuck. Therefore, detection of the excavation diameter of the cutter head of the shield machine is very important.

[0003] Existing detection systems are roughly divided into contact type and non-contact type. The former mostly sets a hydraulic oil cavity on the cutter that protrudes from the outer circumferential surface of the cutter head. The wear of the cutter is determined by monitoring whether the hydraulic oil pressure is lost, and the excavation diameter data of the cutter head is indirectly obtained. Since the cutter protrudes from the outer circumferential surface of the cutter head, the counterforce of the rock and soil is greater. Setting the hydraulic oil cavity reduces the overall strength of the cutter, resulting in a shorter service life of the cutter. Meanwhile, after the cutter wears, mud is also easy to enter the hydraulic oil pipeline and form a blockage. In this case, the hydraulic oil can still establish pressure, and the accuracy and reliability of the detection result are poor. The latter mostly achieves detection by setting fiber optic sensors, Hall sensors, ultrasonic sensors, and the like on the outer circumferential surface of the cutter head. Although this type of sensor has high detection accuracy, it has high requirements for the working environment, and measures such as waterproofing, dustproofing, and impact protection need to be taken. The structure is complex. Rock, debris, and mud on the inner wall of the tunnel can also interfere with the detection results of the sensor, causing misjudgment. In addition, the signal line of the sensor needs to be led out after the cutter support and the center rotating joint, and the layout distance is long. It is also easy to be broken by rock, debris, and mud at the cutter position, which is very fragile, making the accuracy and reliability of the detection result poor. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a double-oil-cylinder series detection system for detecting the excavation diameter of a cutter head of a shield machine, which has good detection result accuracy and reliability.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is a double-oil-cylinder series detection system for detecting the excavation diameter of a cutter head of a shield machine, which comprises:

[0006] A first oil cylinder is arranged on the cutter head and close to the outer circumferential surface of the cutter head. The top rod of the first oil cylinder can extend or retract along the radial direction of the cutter head.

[0007] A second oil cylinder is arranged on the support of the shield machine and located behind the cutter head.

[0008] An oil circuit for feeding and returning oil to the first and second oil cylinders, the oil circuit comprising a supply pipe connecting an oil source and an oil inlet of the first oil cylinder, a connecting pipe connecting an oil return of the first oil cylinder and an oil inlet of the second oil cylinder, and a return pipe connecting an oil return of the second oil cylinder and an oil return tank;

[0009] A sensor for detecting the extension and retraction distance of the top rod of the second oil cylinder;

[0010] A control center connected to the sensor, the control center being configured to receive the detection value of the sensor and convert it into the excavation diameter of the cutter head of the shield tunneling machine;

[0011] When the first cylinder top rod extends out of the outer circumferential surface, the second cylinder top rod is synchronously extended, and when the first cylinder top rod abuts against the inner wall of the tunnel, the detection value of the sensor no longer changes, and the control center converts the extension distance of the first cylinder top rod according to the detection value to calculate the excavation diameter of the cutter head.

[0012] Preferably, the end surface of the first oil cylinder top rod is a conical surface, and the included angle between the generatrix of the conical surface and the axis of the first oil cylinder top rod is 83-87 degrees.

[0013] Preferably, the oil circuit is provided with a control valve group, the control valve group comprising a switching valve group, a supply valve group and a return valve group, the switching valve group being arranged on the supply pipe and the return pipe and being arranged close to the oil source and the oil return tank, the supply valve group being connected to the supply pipe and being arranged between the switching valve group and the first oil cylinder, and the return valve group being connected to the return pipe and being arranged between the switching valve group and the second oil cylinder.

[0014] Further preferably, the switching valve group is a three-position four-way reversing valve, the supply valve group and the return valve group are arranged correspondingly, the supply valve group comprises a first hydraulic control check valve, a first speed regulating valve, a first safety valve and a supply pressure sensor arranged at intervals, the return valve group comprises a second hydraulic control check valve, a second speed regulating valve, a second safety valve and a return pressure sensor arranged at intervals, the hydraulic control circuits of the first hydraulic control check valve and the second hydraulic control check valve are arranged in an alternating manner, and the pressure relief openings of the first safety valve and the second safety valve are both connected to the oil return tank.

[0015] Further preferably, the control valve group further comprises a manual ball valve connected in parallel to the second oil cylinder.

[0016] Preferably, the sensor is a displacement sensor, and the sensor is integrated in the second oil cylinder or arranged outside the second oil cylinder.

[0017] Preferably, the oil supply pipe comprises a first oil supply section connected to the first through hole of the central rotary sleeve, an oil supply channel arranged in the central rotary shaft, a second oil supply section connected between the end of the central rotary shaft and the central block of the cutter head, and a third oil supply section connected between the central block of the cutter head and the first oil cylinder oil supply port, the first oil supply section is used to connect an oil source, the oil supply channel comprises vertically communicated oil supply axial channels and oil supply radial channels, and an oil supply annular groove is arranged on the outer wall of the central rotary shaft to communicate the oil supply radial channels with the first through hole;

[0018] The connecting pipe comprises a first connecting section connected to the second through hole of the central rotary sleeve, a connecting channel arranged in the central rotary shaft, a second connecting section connected between the end of the central rotary shaft and the central block of the cutter head, and a third connecting section connected between the central block of the cutter head and the first oil cylinder oil return port, the first connecting section is used to connect the second oil cylinder oil inlet port, the connecting channel comprises vertically communicated connecting axial channels and connecting radial channels, and a connecting annular groove is arranged on the outer wall of the central rotary shaft to communicate the connecting radial channels with the second through hole;

[0019] The oil supply axial channels and the connecting axial channels are symmetrically arranged on both sides of the axial center line of the central rotary shaft, the oil supply annular groove and the connecting annular groove are arranged in the axial direction of the central rotary shaft, the second oil supply section and the second connecting section are arranged in parallel and along the inner cavity of the cutter head rotary frame, and the third oil supply section and the third connecting section are arranged in parallel and along the cutter head spoke.

[0020] Further preferably, side plates are arranged on both sides of the cutter head spoke, and an end of the side plate away from the cutter head spoke is connected with an end plate, the end plate, the side plate and the side wall of the cutter head spoke form a cavity in which the third oil supply section and the third connecting section are arranged.

[0021] Further preferably, a positioning groove is arranged on the cutter head rotary frame to accommodate the second oil supply section and the second connecting section.

[0022] Further preferably, the end of the first oil cylinder top rod is provided with a hard alloy layer, the thickness of the hard alloy layer is not less than 5 mm, the telescopic limit distance of the first oil cylinder top rod is 45 mm, and the distance between the end surface of the first oil cylinder top rod and the outer peripheral surface is not less than 5 mm when the first oil cylinder top rod is retracted to the outer peripheral surface.

[0023] Thanks to the above technical scheme, the present application has the following advantages compared with the prior art:

[0024] 1. Abandon the way of setting hydraulic oil cavity on the cutter, through setting the first oil cylinder in the position close to the outer circumferential surface of the cutter, the top rod of the first oil cylinder can extend and retract along the radial direction of the cutter, in the tunneling, the actual position of the inner wall of the tunnel can be detected through the first oil cylinder top rod extending out of the outer circumferential surface, and then the extension distance of the second oil cylinder top rod synchronously extending and retracting with the first oil cylinder top rod can be detected, so that the extension distance of the first cylinder top rod can be converted, and the excavation diameter of the cutter head can be calculated, the service life of the cutter is not affected, the phenomenon of blocking the oil way does not appear, and the accuracy and reliability of the detection result are better.

[0025] 2. Through setting the second oil cylinder on the shield machine support and behind the cutter, the sensor for detecting the extension and retraction distance of the second oil cylinder top rod can be arranged away from the cutter, is not affected by the rock, debris, mud and the like, the arrangement requirement is loose and not harsh, the structure is simple, the signal line of the sensor does not need to pass through the cutter and the central rotary joint, is not easy to be damaged, and the accuracy and reliability of the detection result are better.

[0026] 3. In the detection, the protruding part on the inner wall of the tunnel is not affected, and the excavation diameter of the cutter can be detected in the tunneling. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the axial sectional view of the shield machine of the present application, and the oil supply valve group and the oil return valve group are not shown.

[0028] Figure 2 is Figure 1 the sectional view of A-A direction in the figure.

[0029] Figure 3 is Figure 1 the local enlarged view of B in the figure.

[0030] Figure 4 is Figure 1 the local enlarged view of C in the figure.

[0031] Figure 5 is Figure 2 the sectional view of D-D direction in the figure.

[0032] Figure 6 is Figure 1 the oil way in the figure.

[0033] Figure 7 is Figure 3 the local enlarged view of the oil supply oil channel and the connecting oil channel in the figure.

[0034] Figure 8 is the local enlarged view of B in the figure of another embodiment of the present application. Figure 1

[0035] ​Wherein: 10. First hydraulic cylinder; 11. Push rod; 111. Conical surface; 112. Hard alloy layer; 20. Second hydraulic cylinder; 21. Push rod; 311. First oil supply section; 312. Oil supply passage; 3121. Axial oil supply passage; 3122. Radial oil supply passage; 3123. Annular oil supply groove; 313. Second oil supply section; 314. Third oil supply section; 321. First connecting section; 322. Connecting passage; 3221. Axial connecting passage; 3222. Radial connecting passage; 3223. Annular connecting groove; 323. Second connecting section; 324. Third connecting section; 33. Return oil pipe; 341. Switching valve group; 342. Oil supply valve group; 3421. First hydraulic check valve; 342 2. First speed control valve; 3423. First safety valve; 3424. Oil supply pressure sensor; 343. Return oil valve assembly; 3431. Second hydraulic check valve; 3432. Second speed control valve; 3433. Second safety valve; 3434. Return oil pressure sensor; 344. Manual ball valve; 35. Oil source; 36. Return oil tank; 40. Sensor; 51. Cutterhead; 511. Outer circumference; 512. Cutterhead slewing frame; 5121. Positioning groove; 513. Cutterhead spokes; 5131. Side plate; 5132. Sealing plate; 5133. Cavity; 514. Cutterhead center block; 52. Tunnel boring machine support; 531. Central slewing shaft; 532. Central slewing sleeve; 5321. First through hole; 5322. Second through hole. Detailed Implementation

[0036] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0037] like Figures 1 to 7 As shown, the dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead provided by the present invention includes: a first hydraulic cylinder 10, a second hydraulic cylinder 20, an oil circuit, a sensor 40, and a control center (not shown in the figure). The first hydraulic cylinder 10 is mounted on the cutterhead 51 and close to its outer peripheral surface 511. The push rod 11 of the first hydraulic cylinder 10 can extend or retract from the outer peripheral surface 511 in the radial direction of the cutterhead 10. The second hydraulic cylinder 20 is mounted on the tunnel boring machine support 52 and located behind the cutterhead 51. The oil circuit is used for the first hydraulic cylinder 10. The oil circuit for the second cylinder 20 includes an oil supply pipe connecting the oil source 35 to the oil inlet of the first cylinder 10, a connecting pipe connecting the oil return port of the first cylinder 10 to the oil inlet of the second cylinder 20, and a return pipe 33 connecting the oil return port of the second cylinder 20 to the return oil tank 36; the sensor 40 is a displacement sensor, which is used to detect the extension distance of the push rod 21 of the second cylinder 20; the control center is connected to the sensor 40, which is used to receive the detection value of the sensor 40 and convert it into the excavation diameter of the tunnel boring machine cutterhead.

[0038] In this way, the second oil cylinder 20 top rod 21 and the first oil cylinder 10 top rod 11 can be synchronized (including the same speed and different speeds) to extend, when the oil supply pipe supplies oil, the first cylinder body 10 top rod 11 extends out of the outer peripheral surface 511, and the second cylinder body 20 top rod 21 follows to extend synchronously, when the first cylinder body 10 top rod 11 abuts against the inner wall of the tunnel, the detection value of the sensor 40 no longer changes, and the control center calculates the extension distance of the first cylinder body 10 top rod 11 according to the detection value, thereby calculating the excavation diameter of the cutter head.

[0039] The advantages of this arrangement are:

[0040] 1. The method of arranging a hydraulic oil chamber on the cutter is abandoned, which does not affect the service life of the cutter and does not cause the phenomenon of blocked oil way, and the accuracy and reliability of the detection result are better.

[0041] 2. The sensor can be arranged away from the cutter head and is not affected by rock blocks, debris, mud and the like, and the arrangement requirement is loose and not harsh, the structure is simple, the signal line of the sensor is not required to pass through the cutter head and the central rotary joint, and is not easy to be damaged, and the accuracy and reliability of the detection result are better.

[0042] 3. During detection, the protrusions on the inner wall of the tunnel do not affect the real-time detection of the excavation diameter of the cutter head during tunneling, and if the excavation diameter is found to be too small during the detection process, the position where the excavation diameter is too small can be specifically reflected.

[0043] 4. Without relying on manual operation, automatic detection can be completely realized, the adverse consequences caused by human error operation are reduced, installation is simple and easy to understand, and protection of the sensor signal cable does not need to be considered.

[0044] The conversion method of the control center will be described below.

[0045] When the control center receives the detection value of the sensor 40, the extension distance of the second oil cylinder 20 top rod 21 can be known, and the extension distance of the first oil cylinder 10 top rod 11 can be obtained by multiplying the ratio of the piston cavity cross-sectional areas of the first oil cylinder 10 and the second oil cylinder 20.

[0046] For convenience of control, a control valve group is arranged on the oil way in the embodiment, the control valve group includes a switching valve group 341, an oil supply valve group 342 and an oil return valve group 343, the switching valve group 341 is arranged on the oil supply pipe and the oil return pipe 33 and is arranged close to the oil source 35 and the oil return tank 36, the oil supply valve group 342 is connected to the oil supply pipe and is located between the switching valve group 341 and the first oil cylinder 10, and the oil return valve group 343 is connected to the oil return pipe 33 and is located between the switching valve group 341 and the second oil cylinder 20.

[0047] Specifically, the switching valve group 341 is a three-position four-way directional valve to control the oil supply pipe and the oil return pipe 33 simultaneously, the oil supply valve group 342 and the oil return valve group 343 are arranged correspondingly, the oil supply valve group 342 comprises a first hydraulic control check valve 3421, a first speed regulating valve 3422, a first safety valve 3423 and an oil supply pressure sensor 3424 arranged at intervals, the first hydraulic control check valve 3421 is located between the first speed regulating valve 3422 and the switching valve group 341, the first speed regulating valve 3422 is located between the first hydraulic control check valve 3421 and the first safety valve 3423, the first safety valve 3423 is located between the first speed regulating valve 3422 and the oil supply pressure sensor 3424, the oil return valve group 343 comprises a second hydraulic control check valve 3431, a second speed regulating valve 3432, a second safety valve 3433 and an oil return pressure sensor 3434 arranged at intervals, the second hydraulic control check valve 3431 is located between the second speed regulating valve 3432 and the switching valve group 341, the second speed regulating valve 3432 is located between the second hydraulic control check valve 3431 and the second safety valve 3433, the second safety valve 3433 is located between the second speed regulating valve 3432 and the oil return pressure sensor 3434, the first hydraulic control check valve 3421 and the second hydraulic control check valve 3431 are arranged in the same direction, at the same time, the hydraulic control circuits of the first hydraulic control check valve 3421 and the second hydraulic control check valve 3431 are arranged in cross, that is, the oil pressure in the oil supply pipe can control the opening and closing of the second hydraulic control check valve 3431, and the oil pressure in the oil return pipe 33 can control the opening and closing of the first hydraulic control check valve 3421; the setting direction of the check valve assembly in the first speed regulating valve 3422 is the same as that in the second speed regulating valve 3432; the relief ports of the first safety valve 3423 and the second safety valve 3433 are connected with the oil return tank 36.

[0048] The advantage of such arrangement is that when the convex part appears on the inner wall of the tunnel, it can be avoided by pushing the first oil cylinder 10 push rod 11 inward, during the process of pushing back, the pressure in the oil supply pipe rises, when its pressure exceeds the set pressure of the first safety valve 3423, the first safety valve 3423 is connected, so that the excess hydraulic oil flows into the oil return tank 36 through the relief port, avoiding damage to the first oil cylinder 10 and other parts.

[0049] To conveniently realize the unification of the initial positions of the top rod 21 of the second oil cylinder 20 and the top rod 11 of the first oil cylinder 10, in the embodiment, the control valve group further comprises a manual ball valve 344 connected in parallel with the second oil cylinder 20. When adjusting the initial positions of the top rod 21 of the second oil cylinder 20 and the top rod 11 of the first oil cylinder 10, the manual ball valve 344 is first opened, and then the switching valve group 341 is switched to the reverse oil supply state. At this time, the high-pressure hydraulic oil provided by the oil source 36 flows into the first oil cylinder 10 through the oil return pipe 33, the manual ball valve 344 and the connecting pipe, so that the top rod 11 of the first oil cylinder 10 is retracted inward to the limit position, and then the top rod 21 of the second oil cylinder 20 is pushed in the retracting direction, so that it is in the limit position of retracting inward. Thus, the unification of the initial positions of the top rod 11 of the first oil cylinder 10 and the top rod 21 of the second oil cylinder 20 is realized. After unification, the manual ball valve is closed, and the switching valve group 341 is switched to the forward oil supply state (flowing in the direction of the arrow in FIG. 13), so that the detection of the cutting diameter of the cutter head is realized. Figure 6

[0050] To further improve the avoidance effect on the protruding part of the inner wall of the tunnel, in the embodiment, the end face of the top rod 11 of the first oil cylinder 10 is a conical surface 111, which can conveniently push the protruding part against the top rod 11 of the first oil cylinder 10. However, the included angle between the generatrix of the conical surface 111 and the axis of the top rod 11 of the first oil cylinder 10 should not be too large or too small. If it is too large, the pushing effect is poor, and the edge part of the top rod 11 is easily damaged. If it is too small, the top of the conical surface 111 is easily pressed into the inner wall of the tunnel during detection, which affects the accuracy of the detection result. In order to consider the pushing effect and the detection result, and better realize the detection of the cutting diameter of the cutter head in the tunneling process, the included angle is preferably 83 to 87 degrees, and in the embodiment, the included angle is 85 degrees.

[0051] To reduce the wear of the conical surface 111 and improve the service life thereof, in the embodiment, the end of the top rod 11 of the first oil cylinder 10 is provided with a hard alloy layer 112, and the conical surface 111 is located at the outermost side of the hard alloy layer 112. The thickness of the hard alloy layer 112 is 5-10 mm, and the retracting limit distance of the top rod 11 of the first oil cylinder 10 is 45 mm. When the top rod 11 of the first oil cylinder 10 is retracted to the outer peripheral surface 511, the distance between the end face (conical surface 111) of the top rod 11 of the first oil cylinder 10 and the outer peripheral surface 511 is 5-10 mm.

[0052] In the embodiment, the sensor 40 is integrated in the second oil cylinder 20, which can make the overall structure more simple, but can increase the cost of the second oil cylinder 20. A oil cylinder with position detection function needs to be used. In other embodiments, as shown in FIG. 14, the sensor 40 is arranged outside the second oil cylinder 20 and connected with the top rod 21 of the second oil cylinder 20 through a connecting plate, which can save cost and use a conventional oil cylinder as the second oil cylinder 20. Figure 8

[0053] ​​The specific structure of the oil supply pipe and the connecting pipe will be described below.

[0054] In the embodiment, the oil supply pipe comprises a first oil supply section 311 connected to the first through hole 5321 of the central rotary sleeve 532, an oil supply channel 312 arranged in the central rotary shaft 531, a second oil supply section 313 connected between the end of the central rotary shaft 531 and the center block 514 of the cutter head, and a third oil supply section 314 connected between the center block 514 of the cutter head and the oil inlet of the first oil cylinder 10. The first oil supply section 311 is connected to the oil source 35 through the switching valve group 341. The oil supply channel 312 comprises vertically communicated oil supply axial channels 3121 and oil supply radial channels 3122, and an oil supply annular groove 3223 formed in the outer wall of the central rotary shaft 531 for connecting the oil supply radial channels 3222 and the first through hole 5321.

[0055] The connecting pipe comprises a first connecting section 321 connected to the second through hole 5322 of the central rotary sleeve 532, a connecting channel 322 arranged in the central rotary shaft 531, a second connecting section 322 connected between the end of the central rotary shaft 531 and the center block 514 of the cutter head, and a third connecting section 323 connected between the center block 514 of the cutter head and the oil return port of the first oil cylinder 10. The first connecting section 321 is used for connecting the oil inlet of the second oil cylinder 20. The connecting channel 322 comprises vertically communicated connecting axial channels 3221 and connecting radial channels 3222, and a connecting annular groove 3223 formed in the outer wall of the central rotary shaft 531 for connecting the connecting radial channels 3222 and the second through hole 5322.

[0056] The oil supply axial channels 3121 and the connecting axial channels 3221 are symmetrically distributed on both sides of the axial line of the central rotary shaft 531. The oil supply annular groove 3123 and the connecting annular groove 3223 are arranged in the axial direction of the central rotary shaft 531. The second oil supply section 313 and the second connecting section 323 are arranged in parallel and along the inner cavity of the cutter head rotary frame 512. The third oil supply section 314 and the third connecting section 324 are arranged in parallel and along the cutter head spoke 513.

[0057] Further, the side plates 5131 are arranged on both sides of the cutter head spoke 513. The end of the side plate 5131 away from the cutter head spoke 513 is connected to the sealing plate 5132. The sealing plate 5132, the side plate 5131 and the side wall of the cutter head spoke 513 form a cavity 5133 in which the third oil supply section 314 and the third connecting section 324 are arranged, so as to protect the third oil supply section 314 and the third connecting section 324 from being damaged by rocks and debris at the cutter head 10.

[0058] Further, the cutter head rotating frame 512 is provided with a positioning groove 5121 for accommodating the second oil supply section 313 and the second connecting section 323, so as to facilitate the arrangement of the second oil supply section 313 and the second connecting section 323.

[0059] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead, comprising: The first hydraulic cylinder is mounted on the cutter head and close to the outer circumferential surface of the cutter head. Its push rod can extend or retract into the outer circumferential surface in the radial direction of the cutter head. The second hydraulic cylinder is mounted on the shield machine support and located behind the cutterhead; The oil circuit for the inlet and outlet oil of the first and second cylinders includes an oil supply pipe connecting the oil source to the oil inlet of the first cylinder, a connecting pipe connecting the oil outlet of the first cylinder to the oil inlet of the second cylinder, and an oil return pipe connecting the oil outlet of the second cylinder to the oil return tank. A sensor used to detect the extension and retraction distance of the second hydraulic cylinder push rod; The control center, connected to the sensors, receives the sensor readings and converts them into the excavation diameter of the tunnel boring machine cutterhead. Its features are: The oil supply pipe includes a first oil supply section connected to the first through hole of the central rotary sleeve, an oil supply passage disposed in the central rotary shaft, a second oil supply section connected between the end of the central rotary shaft and the central block of the cutter head, and a third oil supply section connected between the central block of the cutter head and the oil supply port of the first oil cylinder. The first oil supply section is used to connect the oil source. The oil supply passage includes a vertically connected axial oil supply passage and a radial oil supply passage, as well as an annular oil supply groove opened on the outer wall of the central rotary shaft. The annular oil supply groove is used to connect the radial oil supply passage and the first through hole. The connecting pipe includes a first connecting section connected to the second through hole of the central rotary sleeve, a connecting oil passage disposed in the central rotary shaft, a second connecting section connected between the end of the central rotary shaft and the center block of the cutter head, and a third connecting section connected between the center block of the cutter head and the oil return port of the first oil cylinder. The first connecting section is used to connect the oil inlet of the second oil cylinder. The connecting oil passage includes a vertically connected axial connecting oil passage and a radial connecting oil passage, as well as a connecting annular groove opened on the outer wall of the central rotary shaft. The connecting annular groove is used to connect the radial connecting oil passage and the second through hole. The oil supply axial passage and the connecting axial passage are symmetrically distributed on both sides of the center line of the central rotating shaft. The oil supply annular groove and the connecting annular groove are spaced apart in the axial direction of the central rotating shaft. The second oil supply section and the second connecting section are arranged in parallel and are laid out along the inner cavity of the cutter head rotating frame. The third oil supply section and the third connecting section are arranged in parallel and are laid out along the cutter head spokes.

2. The dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead as described in claim 1, characterized in that: The end face of the first cylinder push rod is a conical surface, and the angle between the generatrix of the conical surface and the axis of the first cylinder push rod is 83 to 87 degrees.

3. The dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead as described in claim 1, characterized in that: The oil circuit is equipped with a control valve group, which includes a switching valve group, an oil supply valve group, and a return valve group. The switching valve group is installed on the oil supply pipe and the oil return pipe, and is located close to the oil source and the return tank. The oil supply valve group is connected to the oil supply pipe and is located between the switching valve group and the first oil cylinder. The return valve group is connected to the return pipe and is located between the switching valve group and the second oil cylinder.

4. The dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead as described in claim 3, characterized in that: The switching valve group is a three-position four-way directional valve. The oil supply valve group and the oil return valve group are arranged correspondingly. The oil supply valve group includes a first hydraulically controlled check valve, a first speed control valve, a first safety valve and an oil supply pressure sensor arranged at intervals. The oil return valve group includes a second hydraulically controlled check valve, a second speed control valve, a second safety valve and an oil return pressure sensor arranged at intervals. The hydraulic control circuits of the first hydraulically controlled check valve and the second hydraulically controlled check valve are arranged crosswise. The pressure relief ports of the first safety valve and the second safety valve are both connected to the oil return tank.

5. The dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead according to claim 3, characterized in that: The control valve assembly also includes a manual ball valve connected in parallel with the second hydraulic cylinder.

6. The dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead according to claim 1, characterized in that: The sensor is a displacement sensor, which is integrated inside the second cylinder or located outside the second cylinder.

7. The dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead according to claim 1, characterized in that: Side plates are provided on both sides of the cutterhead spokes, and a sealing plate is connected to the end of the side plate away from the cutterhead spokes. The sealing plate, the side plates, and the side wall of the cutterhead spokes form a cavity in which the third oil supply section and the third connecting section are arranged.

8. The dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead according to claim 1, characterized in that: The cutter head rotary table is provided with a positioning groove for accommodating the second oil supply section and the second connecting section.

9. The dual-cylinder tandem detection system for detecting the excavation diameter of a tunnel boring machine cutterhead according to any one of claims 1 to 8, characterized in that: The end of the first cylinder push rod is provided with a hard alloy layer, the thickness of the hard alloy layer is not less than 5mm, the extension limit distance of the first cylinder push rod is 45mm, and when the first cylinder push rod retracts to the outer peripheral surface, the distance between the end face of the first cylinder push rod and the outer peripheral surface is not less than 5mm.

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