Heavy shield hob cutter shaft, disc cutter and TMB shield equipment

Abstract

The invention discloses a heavy shield hob cutter shaft, a disc cutter and TMB shield equipment, and belongs to the technical field of tunneling equipment. The cutter shaft comprises the following main metal elements in percentage by mass: 0.28%-0.32% of C, 5.2%-6.2% of Co, 0.6%-0.7% of Mo, 1.0%-1.2% of Cr, 3.5%-4.2% of Ni, 0.005% of S, 0.006% of P, 1.2%-1.6% of Si, 0.48%-0.56% of Mn, 0.05% of Nb and the balance of Fe. The heat treatment process comprises the following steps: carrying out vacuum quenching on the cutter shaft obtained by smelting the metal elements at 880 DEG C for 2 hours, and carrying out oil quenching; tempering at 280 DEG C for 4 hours, wherein the overall hardness after tempering is not lower than HRC50; after the heat treatment process, the plain round part is subjected to high-frequency induction quenching, a hardening layer is 2-3 mm, and finally precise grinding is conducted according to the size required by drawing design till the size requirement is met, so that surface strengthening is highly and completely unified with high strength and high toughness of a base body, and therefore the overall mechanical property of the cutter shaft subjected to heat treatment quenching and tempering has high impact toughness and fracture toughness, and the service life of the cutter shaft is prolonged. The impact toughness is 66.5 J / cm < 2 >.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunneling equipment. More specifically, it relates to a heavy shield cutter head, a disc cutter and a TMB (Tunnel Boring Machine) shield equipment, which are applicable to cutters with a diameter ranging from 17 inches to 26 inches, especially 24 - 26 inch cutters. Background Technique

[0002] The shield tunneling method has been widely used in tunnel construction. It is not only highly efficient, safe, but also economical and environmentally friendly, making it the best choice for modern tunnel engineering construction. The shield tunneling machine is its most modern professional equipment. The disc cutter structure is a special tool used for cutting rocks and soil layers on the shield tunneling machine. It is installed on the cutter head, and during tunnel construction, the cutter ring of the disc cutter structure penetrates into the rock and soil layers. At the same time, the cutter head drives the disc cutter structure to perform revolution and rotation under the drive of the rotating device, enabling the cutter to continuously roll and press on the rock and soil layers, completing the continuous cutting and crushing of the rock and soil layers.

[0003] The commonly used TBM shield cutter currently is a rock-breaking tool that crushes rocks by the rolling and pressing action of the cutter ring on the rock formation. The quality of the TBM shield cutter directly determines the rock-breaking efficiency of the shield machine. The TBM shield cutter installs two sets of tapered roller bearings back-to-back on the roller shaft and separates them with a spacer ring. The cutter ring is installed on the outer circle of the roller. During operation, the roller shaft remains stationary, and the cutter ring rotates around the roller shaft together with the roller and the outer ring of the bearing. At the same time, the cutter rotates around the center of the cutter head with the cutter head to achieve the purpose of crushing rocks. Therefore, the disc cutter head is a key component installed on the cutter head of the shield machine, and its main function is to support the disc cutter and transmit power, enabling it to effectively cut rocks during tunneling. The design and manufacture of the disc cutter head are crucial for the performance and safety of the entire tunneling machine.

[0004] For example, Chinese Patent CN110821505A discloses a 21-22 inch heavy shield hob, which includes a tool shaft, a lower end cover, a cutter ring, a tool body, a sealing bracket, an upper end cover, a metal sealing ring, a rubber functional ring, an inner ring of a tapered roller bearing, an outer ring of a tapered roller bearing, and a bearing spacer ring; the cutter ring is sleeved on the tool body, two outer rings of the tapered roller bearings are fixed in the inner holes on both sides of the tool body, two inner rings of the tapered roller bearings are fixed on the tool shaft, tapered rollers are arranged between the inner ring and the outer ring of the tapered roller bearing, the sealing bracket is fixed in the inner holes on both sides of the tool body, the upper end cover and the lower end cover are respectively fixed at the upper and lower ends of the tool shaft, and the metal sealing ring and the rubber functional ring are arranged between the upper and lower end covers and the sealing bracket. This device greatly improves the safety and service life of the shield hob, and is suitable for continuous operation at high speed, high thrust and long time. Compared with the existing 19-20 inch hobs, the bearing load is increased from 345KN to 455KN, the tool shaft diameter is increased from 120.65mm to 139.7mm, and the ultimate wear amount of the cutter ring is increased from 35-40mm to 45-50mm.

[0005] However, through a large number of uses, it is found that both the fracture toughness and impact toughness of the tool shaft in the prior art need to be further improved. Summary of the Invention

[0006] 1. Problems to be Solved

[0007] Aiming at the technical problems existing in the prior art, the present invention provides a tool shaft for a heavy shield hob, which has high impact toughness and fracture toughness.

[0008] Another object of the present invention is to provide a heavy disc hob.

[0009] Another object of the present invention is to provide a TMB shield equipment with the disc hob.

[0010] 2. Technical Solutions

[0011] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0012] In the first aspect of the present invention, a heavy shield hob cutter shaft is provided, and the mass percentages of its main metal elements 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%, and the rest is Fe; its heat treatment process includes: vacuum quenching the cutter shaft obtained by smelting the metal elements: 880°C * 2h, oil quenching; tempering at 280°C * 4h, and the overall hardness after tempering is not less than HRC50.

[0013] After the heat treatment process, high-frequency induction quenching is carried out on the smooth round part, and the hardened layer is 2 - 3mm. Finally, precision grinding is carried out according to the dimensional requirements of the drawing design. The purpose is to completely unify surface strengthening with high strength and high toughness of the matrix.

[0014] In the second aspect of the present invention, a heavy shield disc cutter is provided, including:

[0015] A cutter shaft, which has a journal step and is provided with threads along the outer circumferential surface of the cutter shaft; the heavy shield hob cutter shaft described in the first aspect is adopted;

[0016] An upper tapered roller bearing and a lower tapered roller bearing sleeved on the cutter shaft. The inner sleeves of the two tapered roller bearings are hot-fitted on the cutter shaft at 80°C. The upper tapered roller bearing and the lower tapered roller bearing are separated by a spacer ring; an elastic spacer ring 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 installed and preloaded, the bearing clearance is adjusted by using the elastic performance of the spacer ring to achieve the required normal preload force.

[0017] A cutter hub sleeved outside the upper tapered roller bearing and the lower tapered roller bearing; when the outer rings of the upper tapered roller bearing and the lower tapered roller bearing are hot-fitted on the cutter hub, after the cutter hub reaches an appropriate thermal expansion degree, the outer rings of the upper tapered roller bearing and the lower tapered roller bearing are quickly and smoothly placed at the corresponding bearing outer ring positions of the cutter hub;

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

[0019] And an upper cover assembly and a lower cover assembly provided at the axial two 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 object of the present invention, the elastic spacer ring is made of high-quality spring steel, and its profile shape is H-shaped. The elastic spacer ring undergoes rough blank machining, heat treatment and quenching and tempering, and finish machining and forming processes. Surprisingly, both the upper tapered roller bearing and the lower tapered roller bearing abut against the H-shaped elastic spacer ring. The H-shaped structure effectively ensures the end face strength of the elastic spacer ring, and the H-shaped structure has good elastic deformation mechanical properties. Through a large number of tests and usage analyses, it is obtained that on the premise of ensuring the upper tapered roller bearing and the lower tapered roller bearing in the upper end cover and the lower end cover, the H-shaped elastic spacer ring can adjust the pre-tightening force, thereby adjusting the clearance of the upper tapered roller bearing and the lower tapered roller bearing, and configuring to achieve a reasonable starting torque and rotation torque of the hob according to different geological requirements.

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

[0022] The upper end cover is pre-tightened with the cutter shaft by internal threads at the large end face of the upper tapered roller bearing. An O-ring seal A is installed between the upper end cover and the large end face of the inner sleeve of the upper tapered roller bearing during the process of pre-tightening the upper tapered roller bearing for end face sealing;

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

[0024] The upper oil seal bracket is arranged inside the upper end cover, and the upper floating seal is arranged on the upper oil seal bracket; at least two O-ring seals A are used for end face sealing between the upper oil seal bracket and the cutter hub;

[0025] The upper oil seal bracket is made of 42CrMo quenched and tempered parts, finish machined and formed, and then subjected to a nitriding process treatment of 0.7 mm on the surface, or the outer inclined mouth is induction hardened after rough turning the shape of the quenched and tempered parts to improve the surface wear resistance, and then the internal dimensions are finish machined to complete the design dimensions;

[0026] During the assembly process of the upper end cover and the upper oil seal bracket, the upper sealing dust ring is used for static friction clearance type stepped sealing, which enhances the sealing effect without affecting the starting torque and maximally blocks the erosion of sediment; an additional O-ring seal A is also installed between them below the upper sealing dust ring for sealing;

[0027] The L-shaped upper sealing and dust-proof ring is made of high-molecular super wear-resistant polyimide TPI material, which has the advantages of stable dimensions, high stiffness, good toughness, wear resistance, high temperature resistance, and corrosion resistance. It can better stabilize the sealing performance of the cutter hub, strictly prevent the erosion of sediment particles on the cutter hub, further protect the safe use of the upper floating seal and the upper tapered roller bearing inside the cutter hub, and has practical significance for extending the service life of heavy-duty hob cutters;

[0028] After the upper end cover is pre-tightened in place, the locking piece is sleeved on the upper end of the cutter shaft for peripheral groove welding, and the welding stop is positioned on the cutter shaft and the upper end cover to prevent the influence of the loosening of the upper end cover thread on the overall pre-tightening force of the upper tapered roller bearing;

[0029] The upper end cover is provided with two symmetrically distributed ZG1 / 4 holes for oil injection and gas measurement, and is equipped with a single-hole pressure relief valve, which automatically discharges the internal pressure of the cutter hub when the internal pressure of the cutter hub is greater than the external pressure by 3 bar, plays a role in balancing the internal pressure of the cutter hub, and at the same time protects the safe use of the upper floating seal inside the cutter hub.

[0030] According to any implementation scheme of the second aspect of the object of the present invention, the lower cover assembly includes a bearing support seat, a lower end cover, a lower oil seal support, a lower sealing and dust-proof ring, and a plurality of O-ring seals B;

[0031] The bearing support seat is hot-fitted at the bottom of the cutter shaft and abuts against the journal step. The bearing support seat and the journal step are sealed with an O-ring seal B; the bearing support seat and the inner ring of the lower tapered roller bearing are sealed with an O-ring seal B. The outer circumferential surface of the bearing support seat is provided with threads, and the lower end cover is pre-tightened by a threaded connection method, and at the same time, an O-ring seal B is arranged at the end face contact part;

[0032] The lower oil seal support is arranged inside the lower end cover, and the lower floating seal is arranged on the lower oil seal support; at least two O-ring seals B are used for sealing the end face between the lower oil seal support and the cutter hub;

[0033] The lower oil seal support is made of 42CrMo quenched and tempered parts, formed by precision machining, and then subjected to a nitriding process with a surface thickness of 0.7 mm, or the outer inclined mouth is subjected to induction hardening after rough turning the shape of the quenched and tempered parts to improve the surface wear resistance, and then the internal dimensions are processed by precision machining to complete the design dimensions;

[0034] During the assembly process of the lower end cover and the lower oil seal support, the lower sealing and dust-proof ring is used for static friction clearance type stepped sealing, which enhances the sealing effect without affecting the starting torque and maximally blocks the erosion of sediment; an additional O-ring seal B is also arranged above the lower sealing and dust-proof ring for sealing.

[0035] The L-shaped lower sealing dust ring is made of high molecular ultra-wear-resistant polyimide TPI material, which has the advantages of stable dimensions, high stiffness, good toughness, wear resistance, high temperature resistance and corrosion resistance. It can better stabilize the sealing performance of the cutter hub, strictly prevent the erosion of sediment particles on the cutter hub, further protect the safe use of the lower floating seal and the lower tapered roller bearing in the cutter hub, and has practical significance for extending the service life of the heavy-duty hob.

[0036] The third aspect of the present invention provides a TMB shield device having the disc hob 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) For the cutter shaft of the heavy shield hob of the present invention, the overall mechanical properties after heat treatment and quenching and tempering of the cutter shaft have high impact toughness and fracture toughness, and its impact toughness is 66.5 J / cm 2 , which is significantly improved compared with the mechanical properties of HRC42-45 after heat treatment of the current 42CrMo material for the cutter shaft of TBM hob, and can match the actual mechanical properties and safe use of 24-26 inch heavy-duty hobs;

[0040] (2) For the heavy shield hob of the present invention, the L-shaped lower sealing dust ring is made of high molecular ultra-wear-resistant polyimide TPI material, which has the advantages of stable dimensions, high stiffness, good toughness, wear resistance, high temperature resistance and corrosion resistance. It can better stabilize the sealing performance of the cutter hub, strictly prevent the erosion of sediment particles on the cutter hub, further protect the safe use of the lower floating seal and the lower tapered roller bearing in the cutter hub, and has practical significance for extending the service life of the heavy-duty hob. Description of the drawings

[0041] The technical solutions of the present invention will be further described in detail below in conjunction with the drawings and embodiments. However, it should be noted that these drawings are only designed for explanatory purposes and therefore do not limit the scope of the present invention. In addition, unless otherwise specified, these drawings are only intended to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0042] Figure 1 It is a schematic structural diagram of the heavy shield disc hob 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 4Schematic diagram of the spacer ring installation structure of the heavy shield disc cutter of the present invention;

[0046] Figures 5 - 7 Third-party inspection report of the cutter shaft of the heavy shield disc cutter of 42CrMo in the prior art;

[0047] Figures 8 - 10 Third-party inspection report of the heavy shield disc cutter of Example 1;

[0048] Explanation of reference numerals:

[0049] 1. Cutter shaft; 1-1. Shaft neck 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. Upper cover assembly; 8-1. Upper end cover; 8-2. Upper oil seal bracket; 8-3. Locking piece; 8-4. Upper sealing dust ring; 8-5. 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. Upper floating seal;

[0053] 11. Lower floating seal. Detailed implementation manners

[0054] The following detailed description of the exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments in which the present invention can be implemented are shown as examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be achieved and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed present invention, but is merely for illustrative purposes and does not limit the description of the features and characteristics of the present invention, to present the best mode of implementing the present invention, and to be sufficient to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is only defined by the appended claims.

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

[0056] The mass percentages of the main metal elements of the heavy shield hob 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%, and the rest is Fe; its heat treatment process includes: vacuum quenching of the cutter shaft obtained by smelting the metal elements: 880°C * 2h, oil quenching; tempering at 280°C * 4h, and the overall hardness after tempering is not less than HRC50;

[0057] After the heat treatment process, high-frequency induction quenching is carried out on the smooth round part (for example, the frequency of the high-frequency quenching induction coil is 250KHz, the power is 90 - 120KW, and the preheating time is 4 - 6 seconds), the hardened layer is 2 - 3mm, and finally it is precision ground to the required dimensions according to the drawing design requirements, with the purpose of fully unifying surface strengthening with high strength and high toughness of the matrix.

[0058] Among them, the overall mechanical properties of the cutter shaft after heat treatment and tempering have relatively high impact toughness and fracture toughness, and its impact toughness is 66.5J / cm 2 , compared with the mechanical properties of HRC42 - 45 after heat treatment of the current TBM hob cutter shaft material 42CrMo, there is a significant improvement, and it can match the actual mechanical properties and safe use of 24 - 26-inch heavy hobs.

[0059] Combined Figures 1 to 4 As shown, the heavy shield disc hob 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, in Figure 1 , 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 upper tapered roller bearing 2 and the lower tapered roller bearing 3 sleeved on the cutter shaft 1, and the inner sleeves of the two sets of tapered roller bearings are hot-fitted on the cutter shaft 1 at 80°C, and the upper tapered roller bearing 2 and the lower tapered roller bearing 3 are separated by a spacer ring 4; an elastic spacer ring 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. When the two sets of tapered roller bearings are installed and preloaded, the clearance of the tapered roller bearings is adjusted by using the elastic performance of the spacer ring 4 to achieve the required normal preload force.

[0061] The starting torque of the hob is mainly achieved by adjusting the clearance between the outer ring and the inner ring cage rollers of two sets of tapered roller bearings. Since the position of the outer ring of the bearing is fixed, the clearance is mainly adjusted by changing the height of the spacer ring between the inner rings of the cage rollers of the two bearings. The accessories related to the torque, such as the cutter hub, cutter shaft, end cover, bearing, floating seal, etc., of the hob are all machined products, and the dimensional tolerances of each accessory cannot be exactly the same. The dimensional accuracy after assembly is an accumulated accuracy. Therefore, the adjustment of the bearing clearance often needs to be configured separately for each hob, that is, the bearing spacer ring is specially configured. At present, the method of adjusting the height of the spacer ring is to select a spacer ring of a certain height, fit it onto the cutter shaft for a complete pre-assembly, then measure the actual torque, and thicken or thin the spacer ring in steps of 0.5 mm per section according to the measured torque, and repeatedly test-fit the hob to reach or approach the process-set torque.

[0062] It should be noted that in this embodiment, the elastic spacer ring 4 is made of high-quality spring steel (such as 60Si2Mn), as Figure 5 shown, its contour shape is H-shaped. Surprisingly, the upper tapered roller bearing and the lower tapered roller bearing both abut against the H-shaped elastic spacer ring. The H-shaped structure effectively guarantees the end face strength of the elastic spacer ring, and the H-shaped structure has good elastic deformation mechanical properties. Through a large number of tests and usage analyses, it is found that on the premise of ensuring the upper tapered roller bearing and the lower tapered roller bearing in the upper end cover and the lower end cover, the H-shaped elastic spacer ring can adjust the pre-tightening force, thereby adjusting the clearance of the upper tapered roller bearing and the lower tapered roller bearing, and configuring to achieve a reasonable starting torque and rotational torque of the hob according to different geological requirements.

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

[0064]

[0065]

[0066] In Figure 1 , the cutter hub 5 is sleeved outside the upper tapered roller bearing 2 and the lower tapered roller bearing 3; when the cutter ring 6 is hot-fitted onto the cutter hub 5, after the cutter hub 5 has the appropriate thermal expansion degree, 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.

[0067] As Figure 1 and Figure 2As shown, a cutter ring 6 is sleeved on the outer circumferential direction of the cutter hub 5. A retaining ring 7 is arranged on one side of the cutter ring 6, and the retaining ring 7 is fixed to the cutter hub 5. The cutting edge angle of the cutter ring 6 is 16°. The cutter ring 6 is installed on the cutter body by interference fit, generally heated to 100 - 200 °C. The retaining ring 7 can be two semi-circular rings, which are snapped into the groove of the cutter hub 5 and then welded into a complete ring.

[0068] As Figure 1 , Figure 2 and Figure 3 shown, the upper cover assembly 8 and the lower cover assembly 9 are arranged at the axial two 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 structures disclosed in the prior art.

[0069] Combined with Figure 1 and Figure 2 shown, 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 pressure relief valve 8-5 and several O-ring seals A8-6. The upper end cover 8-1 is pre-tightened with the cutter shaft 1 by internal threads at the large end face of the upper tapered roller bearing 2. An O-ring seal A8-6 is added between the upper end cover 8-1 and the large end face of the inner sleeve of the upper tapered roller bearing 2 during the process of pre-tightening the upper tapered roller bearing 2 for end face sealing. The upper end cover 8-1 is pre-tightened with the cutter shaft 1 by internal threads at the large end face of the upper tapered roller bearing 2, and at the same time, the upper tapered roller bearing 2, the lower tapered roller bearing 3 and the intermediate elastic spacer ring 4 are pre-tightened synchronously to adjust the surrounding rock strength corresponding to the hob torque.

[0070] In this embodiment, as Figure 2 shown, the upper oil seal bracket 8-2 is arranged inside the upper end cover 8-1, and the upper floating seal 10 is arranged on the upper oil seal bracket 8-2. The end face between the upper oil seal bracket 8-2 and the cutter hub 5 is sealed with two O-ring seals A8-6. The upper oil seal bracket 8-2 is made of 42CrMo quenched and tempered parts, formed by precision machining, and then subjected to a nitriding process of 0.7 mm on the surface, or the outer inclined mouth is induction hardened after rough turning the shape of the quenched and tempered parts to improve the surface wear resistance, and then the internal dimensions are finished by precision machining to complete the design dimensions.

[0071] Among them, during the assembly process of the upper end cover 8-1 and the upper oil seal bracket 8-2, a static friction clearance type stepped seal is carried out by the upper sealing dust ring 8-4. Without affecting the starting torque, the sealing effect is enhanced, and the erosion of sediment is blocked to the greatest extent. An additional O-ring seal A8-6 is also arranged between them for sealing below the upper sealing dust ring 8-4.

[0072] Furthermore, the hob of the present invention is used for underground tunneling, where there is a large amount of sediment. The L-shaped upper sealing dust-proof ring 8-4 is made of high-molecular super wear-resistant polyimide TPI material, which has the advantages of stable dimensions, high stiffness, good toughness, wear resistance, high temperature resistance, and corrosion resistance. It can better stabilize the sealing performance of the cutter hub 5, strictly prevent sediment particles from invading the cutter hub 5, further protect the safe use of the upper floating seal and the upper tapered roller bearing 2 inside the cutter hub 5, and has practical significance for extending the service life of the heavy-duty hob.

[0073] To prevent the influence of the loosening of the thread of the upper end cap 8-1 on the overall pre-tightening force of the upper tapered roller bearing 2, Figure 1 After the upper end cap 8-1 is pre-tightened in place, the locking piece 8-3 is sleeved on the upper end of the cutter shaft 1 and welded with peripheral beveling, and the welding stop is positioned on the cutter shaft 1 and the upper end cap 8-1.

[0074] Combined with Figure 2 As shown, the upper end cap 8-1 is provided with two symmetrically distributed ZG1 / 4 holes for oil injection and gas measurement, and is equipped with a single-hole pressure relief valve 8-5, which automatically discharges the internal pressure of the body when the internal pressure of the cutter hub 5 is greater than the external pressure by 3 bar, balances the internal pressure of the cutter hub 5, and at the same time protects the safe use of the upper floating seal inside the cutter hub 5.

[0075] Combined with Figure 1 and Figure 3 As shown, the lower cover assembly 9 includes a bearing support seat 9-1, a lower end cap 9-2, a lower oil seal bracket 9-3, a lower sealing dust-proof ring 9-4, and several O-ring seals B9-5; the bearing support seat 9-1 is hot-fitted at the bottom of the cutter shaft 1 and abuts against the shaft neck step 1-1, and the bearing support seat 9-1 and the shaft neck step 1-1 are sealed with an O-ring seal B9-5; the inner ring of the bearing support seat 9-1 and the lower tapered roller bearing 3 are sealed with an O-ring seal B9-5, and the outer circumferential surface of the bearing support seat 9-1 is provided with threads, and the lower end cap 9-2 is pre-tightened by a threaded connection method, and at the same time, an O-ring seal B9-5 is arranged at the end face contact part.

[0076] 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 9-1. At the same time, when the tool is repaired, the lower end cover 9-2 and the lower oil seal bracket 9-3 can be disassembled conveniently and quickly, and can be disassembled and assembled quickly, changing the disadvantages brought by the previous limitation that only by pressing down the cutter shaft 1 can the lower end cover 9-2 and the lower floating seal 11 be disassembled: on the one hand, the inner sleeve of the tapered roller bearing is pressed out and pressed in with the cutter shaft 1 many times, and the interference fit gradually decreases due to wear, and the pre-tightening force is not high, resulting in axial slip of the tapered roller bearing under the high-load rolling of the hob, and after a long time, the hob cutter ring 6 is eccentrically worn and the inner sleeve rollers of the tapered roller bearing are abnormally worn seriously; on the other hand, the combined design and assembly method of the upper and lower end covers 9-2 is beneficial to quickly assemble and disassemble and analyze the internal situation of the hob cutter hub 5 while ensuring normal rolling rock breaking of the hob, and quickly repair and replace the lower floating seal 11 and various seals.

[0077] In this embodiment, as Figure 3 shown, the lower oil seal bracket 9-3 is arranged inside the lower end cover 9-2, and the lower floating seal 11 is arranged on the lower oil seal bracket 9-3; the end face between the lower oil seal bracket 9-3 and the cutter hub 5 is sealed by two O-ring seals B9-5.

[0078] Furthermore, the lower oil seal bracket 9-3 is made of 42CrMo quenched and tempered parts, formed by precision machining, and then subjected to a nitriding process of 0.7 mm on the surface, or the outer inclined mouth is induction hardened after rough turning the shape of the quenched and tempered parts to improve the surface wear resistance, and then the internal dimensions are finished by precision machining to complete the design dimensions.

[0079] Furthermore, as Figure 3 shown, during the assembly process of the lower end cover 9-2 and the lower oil seal bracket 9-3, the lower seal dust-proof ring 9-4 is used for static friction clearance type stepped sealing, which enhances the sealing effect without affecting the starting torque and maximally blocks the erosion of sediment; an additional O-ring seal B9-5 is also arranged between them above the lower seal dust-proof ring 9-4.

[0080] Among them, the L-shaped lower seal dust-proof ring 9-4 is made of high molecular ultra-wear-resistant polyimide TPI material, which has the advantages of stable dimensions, high stiffness, good toughness, wear resistance, high temperature resistance and corrosion resistance, better stabilizes the sealing performance of the cutter hub 5, strictly prevents the erosion of sediment particles on the cutter hub 5, further protects the safe use of the lower floating seal 11 and the lower tapered roller bearing 3 inside the cutter hub 5, and has practical significance for extending the service life of the heavy-duty hob.

[0081] Embodiment 1

[0082] The mass percentages of the main metal elements of the heavy shield cutter head 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%, and the rest is Fe; its heat treatment process includes: vacuum quenching of the cutter head shaft obtained by smelting the said metal elements: 880°C * 2h, oil quenching; tempering at 280°C * 4h, and the overall hardness after tempering is HRC52; after the heat treatment process, high-frequency induction quenching is carried out on the smooth round part, with a hardened layer of 2.5mm, and finally precision grinding is carried out to the required dimensions according to the design requirements of the drawing, aiming to achieve the perfect unity of surface strengthening and high strength and high toughness of the matrix.

[0083] σb (MPa) σ0.2 (MPa) <![CDATA[Aku (J / cm 2 )]]> <![CDATA[KIC (MPa·m 1 / 2 )]]> 1810 1590 66.5 110

[0084] Example 2

[0085] The mass percentages of the main metal elements of the heavy shield cutter head 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%, and the rest is Fe; its heat treatment process includes: vacuum quenching of the cutter head shaft obtained by smelting the said metal elements: 880°C * 2h, oil quenching; tempering at 280°C * 4h, and the overall hardness after tempering is HRC51; after the heat treatment process, high-frequency induction quenching is carried out on the smooth round part, with a hardened layer of 2mm, and finally precision grinding is carried out to the required dimensions according to the design requirements of the drawing.

[0086] Example 3

[0087] The mass percentages of the main metal elements of the heavy shield cutter head 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%, and the rest is Fe; its heat treatment process includes: vacuum quenching of the cutter head shaft obtained by smelting the said metal elements: 880°C * 2h, oil quenching; tempering at 280°C * 4h, and the overall hardness after tempering is HRC52; after the heat treatment process, high-frequency induction quenching is carried out on the smooth round part, with a hardened layer of 3mm, and finally precision grinding is carried out to the required dimensions according to the design requirements of the drawing.

[0088] The present invention and its embodiments have been schematically described above. The description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design, without creative efforts, structural modes and embodiments similar to the technical solution without departing from the spirit of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A heavy shield cutter shaft (1), characterized in that: The mass percentages of the main metal elements 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%, and the rest is Fe; the heat treatment process comprises: vacuum quenching the knife shaft obtained by smelting the metal elements: 880℃*2h, oil quenching; tempering at 280℃*4h, and the overall hardness after tempering is not less than HRC50; after the heat treatment process, the light round part is subjected to high-frequency induction quenching, and the hardened layer is 2-3mm.

2. A heavy shield cutter, characterized in that: include: A cutter shaft (1) having 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 shield hob cutter shaft (1) as claimed in claim 1; An upper tapered roller bearing (2) and a lower tapered roller bearing (3) sleeved on the knife shaft (1), wherein the upper tapered roller bearing (2) and the lower tapered roller bearing (3) are separated by a spacer ring (4); A cutter hub (5) sleeved on the outside of 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), a retaining ring (7) is arranged 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 arranged at both axial ends of the cutter shaft (1), an upper floating seal (10) is arranged between the upper cover assembly (8) and the upper tapered roller bearing (2); and a lower floating seal (11) is arranged between the lower cover assembly (9) and the lower tapered roller bearing (3).

3. The heavy shield cutter according to claim 2, characterized in that: The material of the spacer ring (4) is spring steel, and its profile shape is H-shaped.

4. The heavy shield cutter according to claim 3 is characterized in that: The upper cover assembly (8) comprises an upper end cover (8-1), an upper oil seal bracket (8-2), a locking plate (8-3), an upper sealing dust ring (8-4), a pressure relief valve (8-5) and a plurality of O-type sealing rings 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) by means of an internal thread. During the process of pre-tightening the upper tapered roller bearing (2), an O-type sealing 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 perform end face sealing. 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) by means of an internal thread. The upper oil seal bracket (8-2) is arranged on the inner side of the upper end cover (8-1), and the upper floating seal (10) is arranged on the upper oil seal bracket (8-2); the end surface between the upper oil seal bracket (8-2) and the cutter hub (5) is sealed by at least two O-rings A (8-6); During the assembly process, the upper end cover (8-1) and the upper oil seal bracket (8-2) are subjected to static friction gap step sealing by the upper sealing dust ring (8-4); After the upper end cover (8-1) is pre-tightened into place, the locking piece (8-3) is inserted into the upper end of the knife shaft (1) for peripheral groove welding.

5. The heavy shield cutter according to claim 2, characterized in that: The upper end cover (8-1) is provided with two symmetrically distributed ZG1 / 4 holes for oil injection and gas measurement, and is equipped with a single-hole pressure relief valve (8-5).

6. The heavy shield cutter 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 shield cutter according to claim 6, characterized in that: An O-type sealing ring A (8-6) is also provided 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 shield cutter according to claim 2, characterized in that: The lower cover assembly (9) comprises 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 a plurality of O-type sealing rings B (9-5); The bearing support seat (9-1) is heat-fitted on the bottom of the knife shaft (1) and abuts against the shaft neck step (1-1); the bearing support seat (9-1) and the shaft neck step (1-1) are sealed with an O-ring B (9-5); the bearing support seat (9-1) and the inner ring of the lower tapered roller bearing (3) are sealed with an O-ring B (9-5); the outer circumferential surface of the bearing support seat (9-1) is provided with a thread; the lower end cover (9-2) is pre-tightened with the threaded connection method, and an O-ring B (9-5) is configured at the end surface contact portion; The lower oil seal bracket (9-3) is arranged on the inner side of the lower end cover (9-2), and the lower floating seal (11) is arranged on the lower oil seal bracket (9-3); the end surface between the lower oil seal bracket (9-3) and the cutter hub (5) is sealed by at least two O-rings B (9-5); During the assembly process, the lower end cover (9-2) and the lower oil seal bracket (9-3) are subjected to static friction gap-type step sealing by the lower sealing dust ring (9-4).

9. The heavy shield cutter 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 TMB shield equipment having the heavy shield cutter according to any one of claims 2 to 9.

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