A heavy-duty shield tunnel cutter shaft, disc cutter head, and TBM shield tunneling equipment

Abstract

This invention discloses a heavy-duty shield tunneling cutterhead, a disc cutter, and a TBM (Tunnel Boring Machine) shield equipment, belonging to the technical field of tunneling equipment. The cutterhead's main metallic element mass percentages are as follows: C: 0.28%–0.32%, Co: 5.2%–6.2%, Mo: 0.6%–0.7%, Cr: 1.0%–1.2%, Ni: 3.5%–4.2%, S: 0.005%, P: 0.006%, Si: 1.2%–1.6%, Mn: 0.48%–0.56%, Nb 0.05%, with the remainder being Fe. Its heat treatment process includes smelting the aforementioned metallic elements to obtain... The tool shaft undergoes vacuum quenching at 880℃ for 2 hours, followed by oil quenching; tempering at 280℃ for 4 hours, resulting in an overall hardness of not less than HRC50. After heat treatment, the smooth circular portion is subjected to high-frequency induction hardening, resulting in a 2-3mm hardened layer. Finally, it is precision ground to the required dimensions according to the design drawings. This process ensures that surface strengthening and the high strength and toughness of the matrix are perfectly aligned. Therefore, the overall mechanical properties of the tool shaft after heat treatment and tempering exhibit high impact toughness and fracture toughness, with an impact toughness of 66.5 J / cm². 2 .

Description

Technical Field

[0001] This invention belongs to the field of tunneling equipment technology, and more specifically, relates to a heavy-duty shield cutter shaft, disc cutter and TBM (Tunnel Boring Machine) shield equipment, suitable for 17-inch to 26-inch cutters, especially 24-26 inch cutters. Background Technology

[0002] Shield tunneling is widely used in tunnel construction due to its high efficiency, safety, and economic and environmental benefits, making it the best choice for modern tunnel engineering. The shield tunneling machine is its most modern and specialized equipment. The disc cutter head is a special cutting tool used on the shield tunneling machine for cutting rock and soil layers. Mounted on the cutterhead, the cutter rings of the disc cutter head penetrate the rock and soil layers during tunnel construction. Simultaneously, the cutterhead, driven by a rotating mechanism, causes the disc cutter head to rotate and revolve, continuously rolling and pressing the cutter head against the rock and soil layers, thus completing the continuous cutting and crushing of the rock and soil.

[0003] The commonly used TBM (Tunnel Boring Machine) cutterhead is a rock-breaking tool that crushes rock through the rolling and crushing action of the cutter ring against the rock strata. The quality of the TBM cutterhead directly determines the rock-breaking efficiency of the tunnel boring machine. The TBM cutterhead consists of two sets of tapered roller bearings mounted back-to-back on a roller shaft, separated by a spacer ring. The cutter ring is mounted on the outer circumference of the roller. During operation, the roller shaft remains stationary, while the cutter ring rotates around the roller shaft along with the roller and the outer ring of the bearing. Simultaneously, the cutterhead revolves around the center of the cutterhead to achieve the purpose of crushing rock. Therefore, the disc cutterhead shaft is a key component mounted on the TBM cutterhead. Its main function is to support the disc cutterhead and transmit power, enabling it to effectively cut rock during tunneling. The design and manufacture of the disc cutterhead shaft are crucial to the performance and safety of the entire tunnel boring machine.

[0004] For example, Chinese patent CN110821505A discloses a 21-22 inch heavy-duty tunnel boring machine cutterhead, including a cutter shaft, a lower end cover, a cutter ring, a cutter body, a sealing bracket, an upper end cover, a metal sealing ring, a rubber functional ring, a tapered roller bearing inner sleeve, a tapered roller bearing outer sleeve, and a bearing spacer ring. The cutter ring is fitted onto the cutter body, two tapered roller bearing outer sleeves are fixed in the inner holes on both sides of the cutter body, two tapered roller bearing inner sleeves are fixed on the cutter shaft, tapered rollers are arranged between the tapered roller bearing inner sleeves and tapered roller bearing outer sleeves, the sealing bracket is fixed in the inner holes on both sides of the cutter body, the upper end cover and the lower end cover are respectively fixed at the upper and lower ends of the cutter shaft, and the metal sealing ring and the rubber energy supply ring are arranged between the upper and lower end covers and the sealing bracket. This device significantly improves the safety and service life of the tunnel boring machine cutterhead and is suitable for high-speed, high-thrust, long-term continuous operation. Compared to existing 19-20 inch hobs, the bearing load has been increased from 345KN to 455KN, the cutter shaft diameter has been increased from 120.65mm to 139.7mm, and the limit wear of the cutter ring has been increased from 35-40mm to 45-50mm.

[0005] However, extensive use has revealed that the fracture toughness and impact toughness of the existing cutter shaft technology need further improvement. Summary of the Invention

[0006] 1. The problem to be solved

[0007] To address the technical problems existing in the prior art, the present invention provides a heavy-duty shield tunnel cutter shaft with high impact toughness and fracture toughness.

[0008] Another objective of this invention is to provide a heavy-duty shield tunneling disc cutterhead.

[0009] Another object of the present invention is to provide a TBM shield tunneling device having the disc cutter head.

[0010] 2. Technical Solution

[0011] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0012] The first aspect of this invention provides a heavy-duty shield tunneling cutter shaft, the main metal elements of which are present in the following mass percentages: C: 0.28%–0.32%, Co: 5.2%–6.2%, Mo: 0.6%–0.7%, Cr: 1.0%–1.2%, Ni: 3.5%–4.2%, S: 0.005%, P: 0.006%, Si: 1.2%–1.6%, Mn: 0.48%–0.56%, Nb: 0.05%, with the remainder being Fe; the heat treatment process includes: vacuum quenching the cutter shaft obtained by smelting the aforementioned metal elements at 880℃. 2 hours, oil quenching; tempering at 280℃ After tempering for 4 hours, the overall hardness is not less than HRC50.

[0013] After heat treatment, the round part is subjected to high-frequency induction hardening, with a hardened layer of 2-3mm. Finally, it is precision ground to the required dimensions according to the design drawings. The purpose is to achieve complete unity between surface strengthening and the high strength and high toughness of the substrate.

[0014] A second aspect of the present invention provides a heavy-duty shield tunneling disc cutterhead, comprising:

[0015] The cutter shaft has a journal step and is threaded along the outer circumference of the cutter shaft; the heavy-duty shield tunneling cutter shaft described in the first aspect is adopted;

[0016] An upper tapered roller bearing and a lower tapered roller bearing are fitted onto the cutter shaft. The inner sleeves of the two tapered roller bearings are heat-fitted onto the cutter shaft at 80°C. The upper tapered roller bearing and the lower tapered roller bearing are separated by a spacer. An elastic spacer is installed between the end faces of the inner sleeves of the upper tapered roller bearing and the lower tapered roller bearing. When the two tapered roller bearings are pre-tightened, the elastic properties of the spacer are used to adjust the bearing clearance to achieve the required pre-tightening force.

[0017] A cutter hub is fitted around the upper tapered roller bearing and the lower tapered roller bearing. When the cutter ring is hot-mounted onto the cutter hub, the outer rings of the upper tapered roller bearing and the lower tapered roller bearing are quickly and smoothly placed into the corresponding bearing outer ring positions of the cutter hub after the cutter hub has a suitable thermal expansion time.

[0018] At least one cutting ring is sleeved on the outer circumference of the cutting hub, and a retaining ring is provided on one side of the cutting ring, and the retaining ring is fixed to the cutting hub;

[0019] The upper cover assembly and the lower cover assembly are disposed at both axial ends of the cutter shaft. An upper floating seal is provided between the upper cover assembly and the upper tapered roller bearing; a lower floating seal is provided between the lower cover assembly and the lower tapered roller bearing.

[0020] According to any embodiment of the second aspect of the present invention, the elastic spacer is made of high-quality spring steel and has an H-shaped profile. The elastic spacer undergoes initial blank machining, heat treatment and tempering, and fine machining to form the shape. Surprisingly, both the upper and lower tapered roller bearings abut against the H-shaped elastic spacer. The H-shaped structure effectively ensures the end face strength of the elastic spacer and possesses good elastic deformation mechanical properties. Through extensive testing and usage analysis, it has been found that, while ensuring the upper and lower tapered roller bearings are properly seated on the upper and lower end caps, the H-shaped elastic spacer can adjust the preload, thereby regulating the clearance of the upper and lower tapered roller bearings. This allows for the configuration of reasonable hob starting torque and rotation torque according to different geological requirements.

[0021] According to any embodiment of the second aspect of the present invention, the upper cover assembly includes an upper end cover, an upper oil seal bracket, a locking plate, an upper sealing dust ring, a single-hole pressure relief valve, and a plurality of O-rings A;

[0022] The upper end cover is pre-tightened to the large end face of the upper tapered roller bearing by the internal thread and the cutter shaft. During the pre-tightening process of the upper tapered roller bearing, an O-ring A is installed between the upper end cover and the large end face of the inner sleeve of the upper tapered roller bearing to seal the end face.

[0023] The upper end cover is pre-tightened with the cutter shaft at the large end face of the upper tapered roller bearing using an internal thread. At the same time, the upper tapered roller bearing, the lower tapered roller bearing, and the intermediate elastic spacer are pre-tightened synchronously to adjust the surrounding rock strength corresponding to the cutter torque.

[0024] The upper oil seal bracket is disposed inside the upper end cover, and the upper floating seal is disposed on the upper oil seal bracket; the end face between the upper oil seal bracket and the blade hub is sealed with at least two O-rings A.

[0025] The upper oil seal bracket is made of 42CrMo quenched and tempered material, precision machined, and then subjected to a 0.7mm nitriding process on the surface. Alternatively, the quenched and tempered part is rough machined and then induction hardened on the outer bevel to improve the surface wear resistance. Finally, the internal dimensions are precision machined to complete the design dimensions.

[0026] During assembly, the upper end cover and the upper oil seal bracket are sealed by the upper sealing dust ring through a static friction gap stepped seal, which enhances the sealing effect and maximizes the resistance to mud and sand erosion without affecting the starting torque; an O-ring A is also added between the two and sealed below the upper sealing dust ring.

[0027] The L-shaped upper sealing dustproof ring is made of high-molecular ultra-wear-resistant polyimide TPI material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance, and corrosion resistance. It better stabilizes the sealing performance of the cutter hub, strictly prevents the erosion of the cutter hub by mud and sand particles, further protects the upper floating seal and upper tapered roller bearing inside the cutter hub for safe use, and has practical significance in extending the service life of heavy-duty hobs.

[0028] After the upper end cover is pre-tightened in place, the locking piece is fitted onto the upper end of the cutter shaft and the surrounding bevel is welded. It is positioned on the cutter shaft and the upper end cover to stop the welding and prevent the upper end cover thread from loosening and affecting the overall pre-tightening force of the upper tapered roller bearing.

[0029] The upper end cover has two symmetrically distributed ZG1 / 4 holes for oil injection and gas testing, and is equipped with a single-hole pressure relief valve. When the internal pressure of the tool hub is greater than the external pressure by 3 bar, the internal pressure is automatically discharged to balance the internal pressure of the tool hub and protect the safe use of the floating seal inside the tool hub.

[0030] According to any embodiment of the second aspect of the present invention, the lower cover assembly includes a bearing support, a lower end cover, a lower oil seal bracket, a lower sealing dust ring, and a plurality of O-rings B;

[0031] The bearing support is heat-fitted to the bottom of the cutter shaft and abuts against the journal step. The bearing support and the journal step are sealed with O-rings B. The bearing support and the inner ring of the lower tapered roller bearing are sealed with O-rings B. The outer circumferential surface of the bearing support is threaded. The lower end cover is pre-tightened with the threaded connection and an O-ring B is provided at the end face contact part.

[0032] The lower oil seal bracket is disposed inside the lower end cover, and the lower floating seal is disposed on the lower oil seal bracket; the end face between the lower oil seal bracket and the blade hub is sealed with at least two O-rings B;

[0033] The lower oil seal bracket is made of 42CrMo quenched and tempered material, precision machined, and then subjected to a 0.7mm nitriding process on the surface. Alternatively, the quenched and tempered part is rough machined and then induction hardened on the outer bevel to improve the surface wear resistance. Finally, the internal dimensions are precision machined to complete the design dimensions.

[0034] During assembly, the lower end cover and the lower oil seal bracket are sealed by a static friction gap stepped seal through the lower sealing dust ring, which enhances the sealing effect and maximizes the resistance to mud and sand erosion without affecting the starting torque; an O-ring B is also added between the two and sealed above the lower sealing dust ring.

[0035] The L-shaped lower sealing dust ring is made of high-molecular ultra-wear-resistant polyimide (TPI) material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance, and corrosion resistance. It better stabilizes the sealing performance of the cutter hub, strictly prevents the erosion of the cutter hub by mud and sand particles, and further protects the lower floating seal and lower tapered roller bearing inside the cutter hub for safe use. It is of practical significance to extend the service life of heavy-duty hobs.

[0036] A third aspect of the present invention provides a TBM (tunnel boring machine) having the disc cutterhead described in the second aspect.

[0037] 3. Beneficial effects

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] (1) The heavy-duty shield tunnel cutter shaft of the present invention has high impact toughness and fracture toughness after heat treatment and tempering, with an impact toughness of 66.5 J / cm. 2 Compared to the current TBM hob shaft material 42CrMo after heat treatment, the mechanical properties are significantly improved, which can match the actual mechanical properties and safe use of 24-26 inch heavy-duty hobs;

[0040] (2) The heavy shield cutter of the present invention has an L-shaped lower sealing dust ring made of high-molecular ultra-wear-resistant polyimide TPI material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance and corrosion resistance. It can better stabilize the sealing performance of the cutter hub, prevent the erosion of the cutter hub by mud and sand particles, further protect the lower floating seal and lower tapered roller bearing in the cutter hub for safe use, and extend the service life of the heavy cutter. Attached Figure Description

[0041] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless specifically indicated, these drawings are intended only to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0042] Figure 1 This is a schematic diagram of the heavy-duty shield tunneling disc cutter of the present invention;

[0043] Figure 2 for Figure 1 An enlarged structural diagram of part A;

[0044] Figure 3 for Figure 1 An enlarged structural diagram of part B;

[0045] Figure 4This is a schematic diagram of the spacer ring installation structure of the heavy shield tunnel disc cutter of the present invention;

[0046] Figures 5-7 A third-party inspection report for the existing 42CrMo heavy-duty shield tunnel disc cutter shaft;

[0047] Figures 8-10 This is a third-party testing report for the heavy-duty shield tunneling disc cutterhead of Example 1;

[0048] Explanation of reference numerals in the attached figures:

[0049] 1. Cutter shaft; 1-1. Journal step; 2. Upper tapered roller bearing; 3. Lower tapered roller bearing; 4. Spacer ring; 5. Cutter hub; 6. Cutter ring; 7. Retaining ring;

[0050] 8. Top cover assembly; 8-1. Top end cover; 8-2. Upper oil seal bracket; 8-3. Locking plate; 8-4. Upper sealing dust ring; 8-5. Single-hole pressure relief valve; 8-6. O-ring A;

[0051] 9. Lower cover assembly; 9-1. Bearing support seat; 9-2. Lower end cover; 9-3. Lower oil seal bracket; 9-4. Lower sealing dust ring; 9-5. O-ring B; 9-6. Configuration hole;

[0052] 10. Floating seal;

[0053] 11. Lower floating seal. Detailed Implementation

[0054] The following detailed description of exemplary embodiments of the invention is taken with reference to the accompanying drawings, which form part of the description and illustrate exemplary embodiments in which the invention may be practiced. While these exemplary embodiments have been described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be implemented and various changes may be made to the invention without departing from the spirit and scope thereof. The more detailed description of embodiments of the invention below is not intended to limit the scope of the claimed invention, but is merely illustrative and not restrictive of the description of the features and characteristics of the invention, to suggest the best mode for carrying out the invention, and is sufficient to enable those skilled in the art to practice the invention. Therefore, the scope of the invention is defined only by the appended claims.

[0055] The following detailed description and exemplary embodiments of the invention can be better understood in conjunction with the accompanying drawings, wherein the elements and features of the invention are identified by reference numerals.

[0056] The main metal element mass percentages of the heavy-duty shield tunneling cutter shaft of the present invention are as follows: C: 0.28%–0.32%, Co: 5.2%–6.2%, Mo: 0.6%–0.7%, Cr: 1.0%–1.2%, Ni: 3.5%–4.2%, S: 0.005%, P: 0.006%, Si: 1.2%–1.6%, Mn: 0.48%–0.56%, Nb: 0.05%, with the remainder being Fe; its heat treatment process includes: vacuum quenching the cutter shaft obtained by smelting the aforementioned metal elements at 880℃. 2 hours, oil quenching; tempering at 280℃ After 4 hours of tempering, the overall hardness should not be lower than HRC50.

[0057] After the heat treatment process, the round part is subjected to high-frequency induction hardening (for example, the frequency of the high-frequency hardening induction coil is 250KHz, the power is 90-120KW, and the preheating time is 4-6 seconds), resulting in a hardened layer of 2-3mm. Finally, it is precision ground to the required dimensions according to the design drawings. The purpose is to achieve complete unity between surface strengthening and the high strength and high toughness of the substrate.

[0058] The cutter shaft, after heat treatment and tempering, exhibits high impact toughness and fracture toughness, with an impact toughness of 66.5 J / cm². 2 Compared to the current TBM hob shaft material 42CrMo with heat treatment and HRC42~45, its mechanical properties are significantly improved, and it can match the actual mechanical properties and safe use of 24-26 inch heavy-duty hobs.

[0059] Combination Figures 1 to 4 As shown, the heavy-duty shield tunneling disc cutter of the present invention includes a cutter shaft 1, an upper tapered roller bearing 2, a lower tapered roller bearing 3, a cutter hub 5, a cutter ring 6, an upper cover assembly 8, and a lower cover assembly 9.

[0060] Among them, Figure 1 In this design, the cutter shaft 1 has a journal step 1-1 and a thread along its outer circumference. An upper tapered roller bearing 2 and a lower tapered roller bearing 3 are fitted onto the cutter shaft 1. The inner sleeves of the two tapered roller bearings are heat-fitted onto the cutter shaft 1 at 80°C. The upper tapered roller bearing 2 and the lower tapered roller bearing 3 are separated by a spacer 4. An elastic spacer 4 is installed between the end faces of the inner sleeves of the upper tapered roller bearing 2 and the lower tapered roller bearing 3. During the pre-tightening of the two tapered roller bearings, the elastic properties of the spacer 4 are used to adjust the clearance of the tapered roller bearings to achieve the required pre-tightening force.

[0061] The starting torque of a hob is primarily achieved by adjusting the clearance between the outer and inner ring cage rollers of two sets of tapered roller bearings. Since the position of the bearing outer ring is fixed, the clearance is mainly adjusted by changing the height of the spacer between the inner rings of the two bearing cage rollers. However, the hob hub, cutter shaft, end cap, bearings, floating seals, and other components related to torque are all machined products, and the dimensional tolerances of each component cannot be perfectly consistent. The dimensional accuracy after assembly is cumulative. Therefore, adjusting the bearing clearance often requires individual configuration for each hob, specifically configuring the bearing spacer. Currently, the method for adjusting the spacer height involves selecting a spacer of a certain height, fitting it onto the cutter shaft for a complete pre-assembly, measuring the actual torque, and then adjusting the thickness or thinning of the spacer in 0.5mm steps based on the measured torque. Repeated trial assembly of the hob is necessary to achieve or approximate the process-set torque.

[0062] It should be noted that in this embodiment, the elastic spacer 4 is made of high-quality spring steel (e.g., 60Si2Mn). Figure 4 As shown, its outline is H-shaped. Surprisingly, both the upper and lower tapered roller bearings abut against the H-shaped elastic spacer. The H-shaped structure effectively ensures the end face strength of the elastic spacer, and also possesses good elastic deformation mechanical properties. Through extensive testing and usage analysis, it has been found that, while ensuring the upper and lower tapered roller bearings are properly seated on the upper and lower end covers, the H-shaped elastic spacer can adjust the preload, thereby regulating the clearance of the upper and lower tapered roller bearings. This allows for the configuration of appropriate hob starting and rotating torques according to different geological requirements.

[0063] The manufacturing process of the elastic spacer ring 4 is as follows: steel pipe blanking -- rough turning -- heat treatment and tempering: quenching temperature 870℃, holding for 2 hours followed by oil quenching, tempering temperature 480℃, tempering time 3 hours, then water cooling. The mechanical properties are as follows:

[0064]

[0065] exist Figure 1 In this process, the cutter hub 5 is sleeved on the outside of the upper tapered roller bearing 2 and the lower tapered roller bearing 3; when the cutter ring 6 is hot-mounted onto the cutter hub 5, the outer rings of the upper tapered roller bearing 2 and the lower tapered roller bearing 3 are quickly and smoothly placed into the corresponding bearing outer ring positions of the cutter hub 5 after the cutter hub 5 has a suitable thermal expansion time.

[0066] like Figure 1 and Figure 2As shown, a blade ring 6 is fitted around the outer circumference of the blade hub 5. A retaining ring 7 is provided on one side of the blade ring 6, and the retaining ring 7 is fixed to the blade hub 5. The blade angle of the blade ring 6 is 16°. The blade ring 6 adopts an interference fit and is generally heated to 100-200°C before being installed on the blade body. The retaining ring 7 can be two semi-circular rings, which are inserted into the groove of the blade hub 5 and then welded into a complete ring.

[0067] like Figure 1 , Figure 2 and Figure 3 As shown, the upper cover assembly 8 and the lower cover assembly 9 are disposed at both axial ends of the cutter shaft 1. An upper floating seal 10 is provided between the upper cover assembly 8 and the upper tapered roller bearing 2; a lower floating seal 11 is provided between the lower cover assembly 9 and the lower tapered roller bearing 3. The structures of the upper floating seal 10 and the lower floating seal 11 are both disclosed in the prior art.

[0068] Combination Figure 1 and Figure 2 The upper cover assembly 8 includes an upper end cover 8-1, an upper oil seal bracket 8-2, a locking piece 8-3, an upper sealing dust ring 8-4, a single-hole pressure relief valve 8-5, and several O-rings A8-6. The upper end cover 8-1 is pre-tightened to the large end face of the upper tapered roller bearing 2 by the cutter shaft 1 using internal threads. During the pre-tightening process of the upper tapered roller bearing 2, O-rings A8-6 are installed between the upper end cover 8-1 and the large end face of the inner sleeve of the upper tapered roller bearing 2 for end face sealing. The upper end cover 8-1 is pre-tightened to the large end face of the upper tapered roller bearing 2 by the cutter shaft 1 using internal threads. At the same time, the upper tapered roller bearing 2, the lower tapered roller bearing 3, and the intermediate elastic spacer 4 are pre-tightened synchronously to adjust the surrounding rock strength corresponding to the hob torque.

[0069] In this embodiment, as Figure 2 As shown, the upper oil seal bracket 8-2 is disposed inside the upper end cover 8-1, and the upper floating seal 10 is disposed on the upper oil seal bracket 8-2; the end face between the upper oil seal bracket 8-2 and the blade hub 5 is sealed with two O-rings A8-6; the upper oil seal bracket 8-2 is made of 42CrMo tempered material, precision machined, and then subjected to a 0.7mm nitriding process on the surface, or the tempered part is rough machined and then induction hardened on the outer bevel to improve the surface wear resistance, and then the internal dimensions are precision machined to complete the design dimensions.

[0070] During assembly, the upper end cover 8-1 and the upper oil seal bracket 8-2 are sealed by the upper sealing dust ring 8-4 through a static friction gap stepped seal, which enhances the sealing effect and maximizes the resistance to mud and sand erosion without affecting the starting torque; an O-ring A8-6 is also added between the two and sealed below the upper sealing dust ring 8-4.

[0071] Furthermore, the cutter head of this invention is used in underground tunneling where a large amount of mud and sand are present. The L-shaped upper sealing dustproof ring 8-4 is made of high-molecular ultra-wear-resistant polyimide TPI material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance, and corrosion resistance. It better stabilizes the sealing performance of the cutter hub 5, strictly prevents mud and sand particles from intruding into the cutter hub 5, and further protects the upper floating seal and upper tapered roller bearing 2 inside the cutter hub 5 for safe use. It is of practical significance to extend the service life of heavy-duty cutter head.

[0072] To prevent the loosening of the threads on the upper end cap 8-1 from affecting the overall preload of the upper tapered roller bearing 2, Figure 1 In the process, after the upper end cover 8-1 is pre-tightened in place, the locking piece 8-3 is fitted onto the upper end of the cutter shaft 1 and the peripheral bevel is welded, and the cutter shaft 1 and the upper end cover 8-1 are positioned for welding stop.

[0073] Combination Figure 2 As shown, the upper end cover 8-1 has two symmetrically distributed ZG1 / 4 holes for oil injection and gas testing, and is equipped with a single-hole pressure relief valve 8-5. When the internal pressure of the cutter hub 5 is greater than the external pressure by 3 bar, the internal pressure is automatically discharged to balance the internal pressure of the cutter hub 5 and protect the safe use of the floating seal inside the cutter hub 5.

[0074] Combination Figure 1 and Figure 3 As shown, the lower cover assembly 9 includes a bearing support 9-1, a lower end cover 9-2, a lower oil seal bracket 9-3, a lower sealing dust ring 9-4, and several O-rings B9-5. The bearing support 9-1 is heat-fitted to the bottom of the cutter shaft 1 and abuts against the journal step 1-1. The bearing support 9-1 and the journal step 1-1 are sealed with O-rings B9-5. The bearing support 9-1 and the inner ring of the lower tapered roller bearing 3 are sealed with O-rings B9-5. The outer circumferential surface of the bearing support 9-1 is threaded. The lower end cover 9-2 is pre-tightened by the threaded connection, and O-rings B9-5 are arranged at the end face contact area.

[0075] It should be noted that the lower end cover 9-2 is provided with four evenly distributed pre-tightening wrench configuration holes 9-6 for pre-tightening with the bearing support seat 9-1. At the same time, it can facilitate quick disassembly and assembly of the lower end cover 9-2 and the lower oil seal bracket 9-3 during tool maintenance. This overcomes the disadvantages of the previous limitation that the end cover 9-2 and the lower floating seal 11 could only be removed by pressing down the cutter shaft 1. On the one hand, the interference fit between the cutter shaft 1 and the inner sleeve of the tapered roller bearing gradually decreases due to wear, resulting in low pre-tightening force. This leads to axial slippage of the tapered roller bearing under the high-load rolling of the hob. After a long time, the hob ring 6 wears unevenly and the inner sleeve of the tapered roller bearing wears abnormally and severely. On the other hand, the combined design and assembly method of the lower end cover 9-2 is beneficial for the hob to ensure normal rolling rock breaking while allowing for quick assembly and disassembly to analyze the internal condition of the hob hub 5 and quickly repair and replace the lower floating seal 11 and other seals.

[0076] In this embodiment, as Figure 3 As shown, the lower oil seal bracket 9-3 is disposed inside the lower end cover 9-2, and the lower floating seal 11 is disposed on the lower oil seal bracket 9-3; the end face between the lower oil seal bracket 9-3 and the blade hub 5 is sealed with two O-rings B9-5.

[0077] Furthermore, the lower oil seal bracket 9-3 is made of 42CrMo tempered material, precision machined, and then subjected to a 0.7mm nitriding process on the surface. Alternatively, the tempered part is rough machined and then induction hardened on the outer bevel to improve the surface wear resistance. Finally, the internal dimensions are precision machined to complete the design dimensions.

[0078] Furthermore, such as Figure 3 As shown, the lower end cover 9-2 and the lower oil seal bracket 9-3 are statically frictionally stepped sealed by the lower sealing dust ring 9-4 during the assembly process. This enhances the sealing effect without affecting the starting torque and maximizes the resistance to mud and sand erosion. An O-ring B9-5 is also added between the two and sealed above the lower sealing dust ring 9-4.

[0079] Among them, the L-shaped lower sealing dust ring 9-4 is made of high-molecular ultra-wear-resistant polyimide TPI material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance, and corrosion resistance. It better stabilizes the sealing performance of the cutter hub 5, strictly prevents the erosion of the cutter hub 5 by mud and sand particles, and further protects the lower floating seal 11 and the lower tapered roller bearing 3 inside the cutter hub 5 for safe use. It is of practical significance to extend the service life of heavy-duty hobs.

[0080] Example 1

[0081] The main metal element mass percentages of the heavy-duty shield tunnel cutter shaft in this embodiment are as follows: C: 0.30%, Co: 5.6%, Mo: 0.65%, Cr: 1.1%, Ni: 4.0%, S: 0.005%, P: 0.006%, Si: 1.5%, Mn: 0.48%~0.56%, Nb 0.05%, with the remainder being Fe; its heat treatment process includes: vacuum quenching the cutter shaft obtained by smelting the aforementioned metal elements at 880℃. 2 hours, oil quenching; tempering at 280℃ After 4 hours of tempering, the overall hardness is HRC52. After the heat treatment process, the round part is subjected to high-frequency induction hardening, with a hardened layer of 2.5mm. Finally, it is precision ground to the required dimensions according to the design drawings. The purpose is to achieve complete unity between surface strengthening and the high strength and high toughness of the matrix.

[0082]

[0083] Example 2

[0084] The main metal element mass percentages of the heavy-duty shield tunneling cutter shaft in this embodiment are as follows: C: 0.28%, Co: 5.2%, Mo: 0.6%, Cr: 1.0%, Ni: 3.5%, S: 0.005%, P: 0.006%, Si: 1.2%, Mn: 0.48%, Nb: 0.05%, with the remainder being Fe; its heat treatment process includes: vacuum quenching the cutter shaft obtained by smelting the aforementioned metal elements at 880℃. 2 hours, oil quenching; tempering at 280℃ After 4 hours of tempering, the overall hardness is HRC51. After the heat treatment process, the round part is subjected to high-frequency induction hardening, with a hardened layer of 2mm. Finally, it is precision ground to the required dimensions according to the design drawings.

[0085] Example 3

[0086] The main metal element mass percentages of the heavy-duty shield tunneling cutter shaft in this embodiment are as follows: C: 0.32%, Co: 6.2%, Mo: 0.7%, Cr: 1.2%, Ni: 4.2%, S: 0.005%, P: 0.006%, Si: 1.6%, Mn: 0.56%, Nb: 0.05%, with the remainder being Fe; its heat treatment process includes: vacuum quenching the cutter shaft obtained by smelting the aforementioned metal elements at 880℃. 2 hours, oil quenching; tempering at 280℃ After 4 hours of tempering, the overall hardness is HRC52. After the heat treatment process, the round part is subjected to high-frequency induction hardening, with a hardened layer of 3mm. Finally, it is precision ground to the required dimensions according to the design drawings.

[0087] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A heavy-duty shield tunneling cutterhead shaft, characterized in that, The constituent elements are as follows by mass percentage: C: 0.28%~0.32%, Co: 5.2%~6.2%, Mo: 0.6%~0.7%, Cr: 1.0%~1.2%, Ni: 3.5%~4.2%, S: 0.005%, P: 0.006%, Si: 1.2%~1.6%, Mn: 0.48%~0.56%, Nb: 0.05%, with the remainder being Fe; the heat treatment process includes: vacuum quenching the cutter shaft obtained by smelting the constituent elements at 880℃ for 2 hours, followed by oil quenching; tempering at 280℃ for 4 hours, with the overall hardness after tempering not less than HRC50; after the heat treatment process, the smooth circular part is subjected to high-frequency induction hardening, resulting in a hardened layer of 2-3 mm.

2. A heavy-duty shield tunnel cutterhead, characterized in that, include: The cutter shaft (1) has a journal step (1-1) and a thread is provided along the outer circumferential surface of the cutter shaft (1); the cutter shaft (1) is the heavy-duty shield cutter shaft as described in claim 1; An upper tapered roller bearing (2) and a lower tapered roller bearing (3) are sleeved on the cutter shaft (1), and the upper tapered roller bearing (2) and the lower tapered roller bearing (3) are separated by a spacer (4); A cutter hub (5) fitted outside the upper tapered roller bearing (2) and the lower tapered roller bearing (3); At least one cutter ring (6) is sleeved on the outer circumferential direction of the cutter hub (5), and a retaining ring (7) is provided on one side of the cutter ring (6), and the retaining ring (7) is fixed to the cutter hub (5); and an upper cover assembly (8) and a lower cover assembly (9) are provided at both ends of the axial direction of the cutter shaft (1), and an upper floating seal (10) is provided between the upper cover assembly (8) and the upper tapered roller bearing (2); and a lower floating seal (11) is provided between the lower cover assembly (9) and the lower tapered roller bearing (3).

3. The heavy-duty shield tunnel cutterhead according to claim 2, characterized in that, The spacer ring (4) is made of spring steel and has an H-shaped profile.

4. The heavy-duty shield tunnel cutterhead according to claim 3, characterized in that, The upper cover assembly (8) includes an upper end cover (8-1), an upper oil seal bracket (8-2), a locking piece (8-3), an upper sealing dust ring (8-4), a single-hole pressure relief valve (8-5), and several O-ring seals A (8-6). The upper end cover (8-1) is pre-tightened with the cutter shaft (1) at the large end face of the upper tapered roller bearing (2) using an internal thread. During the pre-tightening process of the upper tapered roller bearing (2), an O-ring A (8-6) is installed between the upper end cover (8-1) and the large end face of the inner sleeve of the upper tapered roller bearing (2) to seal the end face. The upper end cover (8-1) is pre-tightened with the cutter shaft (1) at the large end face of the upper tapered roller bearing (2) using an internal thread. The upper oil seal bracket (8-2) is located inside the upper end cover (8-1), and the upper floating seal (10) is located on the upper oil seal bracket (8-2); the end face between the upper oil seal bracket (8-2) and the blade hub (5) is sealed with at least two O-ring seals A (8-6); During the assembly process, the upper end cover (8-1) and the upper oil seal bracket (8-2) are sealed by the upper sealing dust ring (8-4) through a static friction gap stepped seal. After the upper end cover (8-1) is pre-tightened, the locking piece (8-3) is fitted onto the upper end of the cutter shaft (1) for peripheral beveling welding.

5. The heavy-duty shield tunnel cutterhead according to claim 4, characterized in that, The upper end cap (8-1) has two symmetrically distributed ZG1 / 4 holes for oil injection and gas testing, and is equipped with a single-hole pressure relief valve (8-5).

6. The heavy-duty shield tunnel cutterhead according to claim 5, characterized in that, The upper sealing dustproof ring (8-4) is made of high molecular weight polyimide TPI material.

7. The heavy-duty shield tunnel cutterhead according to claim 6, characterized in that, An O-ring A (8-6) is added between the upper end cover (8-1) and the upper oil seal bracket (8-2) to seal below the upper sealing dust ring (8-4).

8. The heavy-duty shield tunnel cutterhead according to claim 2, characterized in that, The lower cover assembly (9) includes a bearing support seat (9-1), a lower end cover (9-2), a lower oil seal bracket (9-3), a lower sealing dust ring (9-4), and several O-rings B (9-5). The bearing support seat (9-1) is heat-fitted to the bottom of the cutter shaft (1) and abuts against the journal step (1-1). The bearing support seat (9-1) and the journal step (1-1) are sealed with O-ring seals B (9-5). The bearing support seat (9-1) and the inner ring of the lower tapered roller bearing (3) are sealed with O-ring seals B (9-5). The outer circumferential surface of the bearing support seat (9-1) is threaded. The lower end cover (9-2) is pre-tightened with the threaded connection and O-ring seals B (9-5) are arranged at the end face contact part. The lower oil seal bracket (9-3) is located inside the lower end cover (9-2), and the lower floating seal (11) is located on the lower oil seal bracket (9-3); the end face between the lower oil seal bracket (9-3) and the blade hub (5) is sealed with at least two O-rings B (9-5). During the assembly process, the lower end cap (9-2) and the lower oil seal bracket (9-3) are sealed by the lower sealing dust ring (9-4) through a static friction gap stepped seal.

9. The heavy-duty shield tunnel cutterhead according to claim 8, characterized in that, The lower sealing dustproof ring (9-4) is made of high molecular weight polyimide TPI material.

10. A TBM tunneling machine having a heavy-duty cutterhead as described in any one of claims 2-9.

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