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

Abstract

The invention discloses a heavy shield hob cutter ring, a disc cutter and TMB shield equipment, and belongs to the technical field of tunneling equipment. The cutter ring comprises the following main metal elements in percentage by mass: 0.48%-0.56% of C, 0.68%-0.78% of Si, 0.35%-0.47% of Mn, 5%-5.6% of Cr, 0.9%-1.5% of Mo, 0.45%-0.56% of W, 0.7%-0.85% of V, 0.013% of P / S, 2.8%-3.6% of Ni, 0.085%-0.096% of Cu and the balance of Fe. The heat treatment process comprises the following steps: carrying out 1250 DEG C high-temperature diffusion and multidirectional forging on a steel ingot obtained by smelting the metal elements, repeatedly upsetting and drawing into round steel during cogging, carrying out forging circle ultra-refining, blanking, forging, ring rolling and blank forming, carrying out secondary refining, carrying out spheroidizing annealing, carrying out composite heat treatment after rough machining, carrying out vacuum quenching, and carrying out tempering heat treatment. The vacuum quenching time of the cutter ring is 1030 DEG C * (3-5 hours); 3 times of tempering heat treatment: carrying out 350DEG C * 3h * 2 times; and the overall hardness of one time of tempering at the temperature of (530-540) DEG C * 5h * 3 times of tempering is HRC59, HRC60 and HRC62 respectively.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunneling equipment, and more specifically, relates to a heavy shield cutter ring, a disc cutter and a TMB (Tunnel Boring Machine) shield equipment. The shield cutter ring is suitable for 17-inch to 26-inch cutters, especially 24-26-inch cutters. Background Art

[0002] Shield tunneling construction method is widely used in tunnel construction. It is not only efficient and safe, but also economical and environmentally friendly. It is the best choice for modern tunnel construction, and 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 cutterhead and the cutter ring of the disc cutter structure is penetrated into the rock and soil layer during tunnel construction. At the same time, the cutterhead drives the disc cutter structure to realize revolution and rotation under the drive of the rotating device, so that the cutter continuously rolls on the rock and soil layer to complete the continuous cutting and crushing of the rock and soil layer.

[0003] The commonly used TBM shield cutter is a rock-breaking tool that crushes rocks by rolling and crushing the rock formation with the cutter ring. The quality of the TBM shield cutter directly determines the rock-breaking efficiency of the shield machine. The TBM shield cutter is to install two sets of tapered roller bearings back to back on the roller shaft, separated by a spacer ring in the middle, and the cutter ring is installed on the outer circle of the roller. When working, the roller shaft does not move, and the cutter ring rotates around the roller shaft with the roller and the outer ring of the bearing. At the same time, the cutter rotates around the center of the cutter disc with the cutter disc to achieve the purpose of crushing rocks. It can be seen that the performance of the cutter ring, as an important part of the hob, largely determines the service life of the hob. The article "Research on Heat Treatment Process of TBM Disc Hob Ring Materials" discloses that Wirth and Robbins brands are the most typical TBM disc hobs. The steel used for Wirth hob rings is mostly hot-working die steel such as German DIN standard grade X50CrVMo5-1, and the steel used for Robbins hob rings is mostly alloy structural steel such as American AISI standard grade 4340, while the cutter rings of Japanese companies are mostly cold-working die steel such as Japanese (JS) G4404 standard grade SKD11; and the current domestic cutter ring materials mostly use national standard grades 9Cr2Mo (GB / T 1299-2014), 40CrNiMo (GB / T 3077-2015), 4Cr5MoSiV1 (GB / T1299-2014), etc.

[0004] In addition, domestic research on the composition of cutter ring materials has been ongoing. For example, after searching, Chinese patent CN106756592A discloses a hob cutter ring for tunnel shield construction, including a disc-shaped cutter ring body, the cutter ring body includes a step assembly part for welding and assembling with a cutter hub and a working edge part for cutting, and the outer edge of the cutter ring body is formed with a nitriding layer by plasma nitriding; the cutter ring body is made of cemented carbide steel, and the element composition of the cemented carbide steel contains 0.46-0.55wt% C, 0.20-0.80wt% Mn, 1.5-3.5wt% Cr, 0.30-0.80wt% t% Mo, 0.32-0.80wt% Cu, 0.05-0.20wt% V, the balance is Fe and inevitable metal impurities and non-metallic impurities; the inevitable non-metallic impurities include Si, N, S, P and O, and the content of Si is ≤0.20wt%, the content of N is ≤0.010wt%, the content of P is ≤0.010wt%, the content of S is ≤0.010wt%, and the content of O is ≤20ppm; the inevitable metal impurities include Ti, Zr and Al, and the content of Ti is ≤0.02wt%, the content of Zr is ≤0.02wt%, and the content of Al is ≤0.05wt%.

[0005] Another example is Chinese patent CN103484783A which discloses a disc hob cutter ring alloy, the composition mass percentage is C0.4% to 0.46%, Si0.45% to 1.0%, Mn0.48% to 0.74%, Cr1.3% to 5.4%, Mo0.4% to 1.4%, V0.86% to 1.33%, Nb0.06% to 0.54%, Al0% to 0.05%, Ni0% to 3%, S≤0.009%, P≤0.03%, the balance is Fe, and the preparation method includes vacuum induction melting, pouring, forging, spheroidizing annealing, gas carburizing, vacuum quenching and secondary tempering of the raw materials, and the prepared disc hob cutter ring carburized layer thickness is 1mm, the carburized layer surface hardness can reach 60 to 63HRC, the internal average hardness is greater than 55HRC, and the impact toughness aku reaches 15 to 22J / cm 2 The shield cutter ring has not only high hardness but also good toughness.

[0006] For another example, Chinese patent CN107345267A discloses a disc cutter for TBM, the composition and mass percentage of which are as follows: carbon 0.46% to 0.58%; silicon 0.80% to 1.20%; manganese 0.20% to 0.60%; chromium 4.50% to 5.80%; nickel 0.15% to 0.40%; molybdenum 1.15% to 1.55%; vanadium 0.85% to 1.40%; phosphorus less than 0.02%; sulfur less than 0.01%; and the balance is iron.

[0007] For another example, Chinese patent CN105443137A discloses an integral cutter ring for a disc-shaped hob, the chemical composition mass percentage of the integral cutter ring is: C: 0.39-0.42, Si: 0.25-0.28, Mn: 0.63-0.69, Cr: 0.74-0.78, Mo: 0.16-0.19, Ni: 1.38-1.44, W: 0.12-0.16, Nb: 0.15-0.18, Cu: 0.04-0.09, S: 0.005-0.009, P: 0.01-0.015, and the balance is Fe.

[0008] Based on the above material components, the knife ring production process must go through forging, annealing, quenching, tempering and other processes, among which quenching and tempering as the final heat treatment method have a decisive influence on the final performance of the knife ring. Therefore, many domestic scientific researchers have carried out a lot of research on heat treatment methods: Yan Hong, Chen Lei and others invented a device for quenching knife rings, which makes the cooling rate of the inner circle and the core of the knife ring lower than the blade during the quenching process, so that the inner circle and the core of the knife ring have a different structure from the blade of the knife ring; Yang Longxing controls the temperature of the knife ring entering the furnace, the heating rate, the quenching temperature and the holding time to ensure the quenching quality of the knife ring; Chen Lei sets different quenching and tempering temperatures and holding times, and comprehensively analyzes and determines the optimal quenching and tempering process parameters for the knife ring.

[0009] However, after extensive use, it was found that the overall hardness and impact toughness of the knife ring in the prior art need to be further improved. Summary of the invention

[0010] 1. Problem to be solved

[0011] In view of the technical problems existing in the prior art, the present invention provides a heavy-duty shield cutter ring, which improves the overall hardness and impact toughness of the cutter ring.

[0012] Another object of the present invention is to provide a heavy-duty shield disc cutter.

[0013] Another object of the present invention is to provide a TMB shield equipment having the disc cutter.

[0014] 2. Technical solution

[0015] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0016] The first aspect of the present invention provides a heavy shield hob cutter ring, wherein the mass percentages of the main metal elements are as follows: C: 0.48% to 0.56%, Si: 0.68% to 0.78%, Mn: 0.35% to 0.47%, Cr: 5% to 5.6%, Mo: 0.9% to 1.5%, W: 0.45% to 0.56%, V: 0.7% to 0.85%, P / S: 0.013, Ni: 2.8% to 3.6%, Cu: 0.085% to 0.096%, and the rest is Fe; the heat treatment process includes : The steel ingot obtained by smelting the metal elements is diffused at 1250°C and multi-directionally forged, and is repeatedly upset and drawn into round steel when opening the blank, and is subjected to ultra-fine forging + blanking forging and ring rolling into blank + secondary refinement + spheroidizing annealing + composite heat treatment after rough machining + vacuum quenching and tempering heat treatment; the knife ring is vacuum quenched at 1030°C*(3-5h); 3 tempering heat treatments: 350°C*3h*2 times; (530-540)°C*5h*1 time, and the overall hardness of the 3 temperings corresponds to not less than HRC59, not less than HRC60, and not less than HRC62, respectively.

[0017] After testing, the standard U-shaped pendulum impact test of 10*10*55: 1) Overall hardness HRC (Rockwell hardness) 58-59, aku2=28J, impact toughness: 35J / cm 2 ; 2) Overall hardness HRC60-62, aku2=14.75J, impact toughness: 17.8125J / cm 2 .

[0018] According to any embodiment of the first aspect of the present invention, the ultra-fine forging includes: heating and heat preservation at 1050℃ for 3h, water quenching and air cooling, repeated alternating operations, water quenching time and water out of air cooling time according to the diameter and length of the forging, and circulating in sequence until the last water out of the air cooling temperature is 150℃-200℃, and then immediately transferred to the trolley furnace set at 920℃, heating and heat preservation, so that the whole is heated evenly, and then heat preservation for 5-7h, and then cooled to about 765℃-720℃ with the furnace, and after heat preservation for 6-7h, cooled to 350℃ with the furnace and discharged, and the steps of secondary refinement are the same as above. The sample obtained by the above steps is tested to have a grain size of 8.5 or above.

[0019] According to any embodiment of the first aspect of the present invention, the multi-directional forging includes: multi-directional forging temperature, initial forging temperature 1130-1150°C, final forging temperature 900±10°C, reduction rate gradually reduced from 40%-30%-20%-10%-5%, and stabilizing the thermoplastic.

[0020] According to any embodiment of the first aspect of the present invention, the composite heat treatment is a carbonitriding composite heat treatment process, the depth of the diffusion layer is 1.1-1.3mm, the carbonitriding is carried out at a temperature of 850℃-870℃, which can improve the wear resistance and contact fatigue resistance of the knife ring.

[0021] A second aspect of the present invention provides a heavy shield disc cutter, comprising:

[0022] A cutter shaft having a journal step and a thread arranged along the outer circumference of the cutter shaft;

[0023] The upper tapered roller bearing and the lower tapered roller bearing are sleeved on the cutter shaft. The two sets of tapered roller bearing inner sleeves are hot-mounted 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 upper tapered roller bearing and the lower tapered roller bearing inner sleeve. When the two sets of tapered roller bearings are installed and preloaded, the elastic performance of the spacer ring is used to adjust the bearing clearance to achieve the normal required preload force.

[0024] A cutter hub is sleeved on the outer part of the upper tapered roller bearing and the lower tapered roller bearing; when the cutter rings of the upper tapered roller bearing and the lower tapered roller bearing are heat-fitted on 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;

[0025] At least one cutting ring (in some cases, more than two cutting rings may be provided) sleeved on the outer circumference of the cutting hub, a retaining ring being provided on one side of the cutting ring, and the retaining ring being fixed to the cutting hub (for example, by welding);

[0026] And an upper cover assembly and a lower cover assembly are arranged at the axial ends of the knife shaft, an upper floating seal is arranged between the upper cover assembly and the upper tapered roller bearing; a lower floating seal is arranged between the lower cover assembly and the lower tapered roller bearing.

[0027] According to any implementation scheme of the second aspect of the present invention, the elastic spacer is made of high-quality spring steel, and its contour shape is H-shaped. The elastic spacer undergoes rough initial processing, heat treatment and tempering, and fine processing and configuration molding processes. What surprised the inventors is that the upper tapered roller bearing and the lower tapered roller bearing are both against the H-shaped elastic spacer, and the H-shaped structure effectively ensures the end face strength of the elastic spacer, and the H-shaped structure has good elastic deformation mechanical properties. Through a large number of tests and use analysis, it is found that under the premise of ensuring that the upper tapered roller bearing and the lower tapered roller bearing are on the upper end cover and the lower end cover, the H-shaped elastic spacer can adjust the preload, thereby adjusting the clearance of the upper tapered roller bearing and the lower tapered roller bearing, and according to different geological requirements, the configuration achieves a reasonable hob starting torque and rotation torque.

[0028] 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 pressure relief valve and a plurality of O-rings A;

[0029] The upper end cover is pre-tightened at the large end face of the upper tapered roller bearing with the cutter shaft by means of an internal thread. During the process of pre-tightening the upper tapered roller bearing, an O-type sealing 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 perform end face sealing;

[0030] The upper end cover is pre-tightened at the large end face of the upper tapered roller bearing with the cutter shaft by means of internal threads, and the upper tapered roller bearing, the lower tapered roller bearing and the elastic spacer ring in the middle are pre-tightened synchronously at the same time to adjust the surrounding rock strength corresponding to the cutter torque;

[0031] The upper oil seal bracket is arranged on the inner side of the upper end cover, and the upper floating seal is arranged on the upper oil seal bracket; the end surface between the upper oil seal bracket and the cutter hub is sealed by at least two O-rings A;

[0032] The upper oil seal bracket is made of 42CrMo quenched and tempered parts, finely machined, and then subjected to a 0.7mm nitriding process on the surface, or the quenched and tempered parts are rough-turned and then induction hardened on the outer bevel to improve the surface wear resistance, and then the internal dimensions are finely machined to complete the design dimensions;

[0033] During the assembly process, the upper end cover and the upper oil seal bracket are sealed by the upper sealing dust ring in a static friction gap type step seal, which enhances the sealing effect and blocks the erosion of mud and sand to the maximum extent without affecting the starting torque; an O-ring A is also added between the two to seal under the upper sealing dust ring;

[0034] The L-shaped upper 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 can better stabilize the sealing performance of the cutter hub, strictly prevent the erosion of the cutter hub by sediment particles, and further protect the upper floating seal and upper tapered roller bearing in the cutter hub for safe use, which has practical significance for extending the service life of heavy-duty hobs;

[0035] After the upper end cover is pre-tightened in place, the locking piece is inserted into the upper end of the cutter shaft for peripheral groove welding, and is positioned on the cutter shaft and the upper end cover for welding stop to prevent the loosening of the upper end cover thread from affecting the overall pre-tightening force of the upper tapered roller bearing;

[0036] The upper end cover is provided with two symmetrically distributed ZG1 / 4 holes for oil filling and gas measurement, and is equipped with a single-hole pressure relief valve, which automatically discharges the internal pressure when the internal pressure of the cutter hub is greater than the external pressure by 3 bar, thereby balancing the internal pressure of the cutter hub and protecting the safe use of the upper floating seal in the cutter hub.

[0037] According to any embodiment of the second aspect of the present invention, the lower cover assembly includes a bearing support seat, a lower end cover, a lower oil seal bracket, a lower sealing dust ring, and a plurality of O-rings B;

[0038] The bearing support seat is heat-fitted at the bottom of the knife shaft and abuts against the shaft neck step. The bearing support seat and the shaft neck step are sealed with an O-ring B; the bearing support seat and the inner ring of the lower tapered roller bearing are sealed with an O-ring B. The outer circumferential surface of the bearing support seat is provided with a thread. The lower end cover is pre-tightened in a threaded connection manner, and an O-ring B is configured at the end face contact portion.

[0039] The lower oil seal bracket is arranged on the inner side of the lower end cover, and the lower floating seal is arranged on the lower oil seal bracket; the end surface between the lower oil seal bracket and the cutter hub is sealed by at least two O-rings B;

[0040] The lower oil seal bracket is made of 42CrMo quenched and tempered parts, finely machined, and then subjected to a 0.7mm nitriding process on the surface, or the quenched and tempered parts are rough-turned and then induction hardened on the outer bevel to improve the surface wear resistance, and then the internal dimensions are finely machined to complete the design dimensions;

[0041] During the assembly process, the lower end cover and the lower oil seal bracket are sealed with a static friction gap type step seal by the lower sealing dust ring, which enhances the sealing effect and blocks the erosion of mud and sand to the maximum extent without affecting the starting torque; an O-ring B is also added between the two to seal above the lower sealing dust ring.

[0042] The L-type lower sealing dust ring is made of high molecular super 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, strictly prevent the invasion of mud and sand particles on the cutter hub, further protect the lower floating seal and lower tapered roller bearing in the cutter hub for safe use, and extend the service life of heavy-duty hobs, which has practical significance.

[0043] A third aspect of the present invention provides a TMB shield equipment having the disc cutter described in the second aspect, comprising a cutterhead, and the disc cutter is arranged on the cutterhead.

[0044] 3. Beneficial effects

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The heavy shield hob cutter ring of the present invention has an overall hardness of HRC58-59, aku2=28J, and an impact toughness of 35J / cm 2 ; When the overall hardness is HRC60-62, aku2=14.75J, impact toughness: 17.8125J / cm 2 The metallographic structure is martensite, which has significantly improved mechanical properties compared to 5H13 in the prior art. The performance of the knife ring is better and the service life of the knife ring can be effectively improved.

[0047] (2) The heavy-duty shield disc cutter of the present invention has an L-shaped lower sealing dust ring made of a high-molecular-weight, 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, strictly prevent the invasion of mud and sand particles on the cutter hub, further protect the lower floating seal and the lower tapered roller bearing in the cutter hub for safe use, and extend the service life of the heavy-duty cutter, which has practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0049] Figure 1 The grain size test result of the heavy shield disc cutter ring of the present invention;

[0050] Figure 2 It is a structural schematic diagram of the heavy shield disc cutter of the present invention;

[0051] Figure 3 for Figure 2 A schematic diagram of the enlarged structure of part A;

[0052] Figure 4 for Figure 2 A schematic diagram of the enlarged structure of part B;

[0053] Figure 5 It is a schematic diagram of the installation structure of the spacer ring of the heavy shield disc cutter of the present invention;

[0054] Figure 6-Figure 8 The third-party inspection report of the existing 5H13 heavy shield disc cutter ring;

[0055] Figure 9-11 A third-party inspection report of the heavy shield disc cutter of Example 1;

[0056] Fig.12It is the impact toughness value of the heavy shield disc cutter ring of Example 1.

[0057] Description of reference numerals:

[0058] 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;

[0059] 8. Upper cover assembly; 8-1. Upper end cover; 8-2. Upper oil seal bracket; 8-3. Locking plate; 8-4. Upper sealing dust ring; 8-5. Pressure relief valve; 8-6. O-ring A;

[0060] 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;

[0061] 10. Upper floating seal;

[0062] 11. Bottom floating seal. DETAILED DESCRIPTION

[0063] The following detailed description of exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments of the present invention that 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 implemented 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 invention, but is only for the purpose of illustrating and not limiting the description of the characteristics and features of the present invention, so as to propose the best mode for performing the present invention and to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0064] The following detailed description of the present invention and example embodiments may be better understood in conjunction with the accompanying drawings, in which elements and features of the present invention are identified by reference numerals.

[0065] When the TBM shield equipment is operating in a stratum with relatively uniform rock structure, the load changes on the cutter are also relatively gentle; when the TBM shield equipment is operating in a rock stratum with uneven hardness or the rock stratum structure suddenly hardens, it may cause the cutter ring 6 of the cutter to be locally overloaded and cause the cutter ring 6 to break. Therefore, the overall strength of the cutter ring 6 needs to be improved. The main metal elements of the heavy shield hob cutter ring 6 of the present invention are as follows: C: 0.48% to 0.56%, Si: 0.68% to 0.78%, Mn: 0.35% to 0.47%, Cr: 5% to 5.6%, Mo: 0.9% to 1.5%, W: 0.45% to 0.56%, V: 0.7% to 0.85%, P / S: 0.013, Ni: 2.8% to 3.6%, Cu: 0.085% to 0.096%, and the rest is Fe; the heat treatment process comprises: smelting the metal elements to obtain a steel ingot at a high temperature of 1250°C Diffusion and multi-directional forging, repeated upsetting and drawing into round steel when opening the blank, forging round ultra-fine + blanking forging and rolling ring into blank + secondary refinement + spheroidizing annealing + composite heat treatment after rough machining + vacuum quenching and tempering heat treatment; in order to prevent surface decarburization of the knife ring 6 during quenching heating, the knife ring 6 is vacuum quenched: 1030℃*(3-5h); the knife ring 6 after quenching should be heat treated in time, 3 tempering heat treatments: 350℃*3h*2 times; (530-540)℃*5h*1 time, the overall hardness of the 3 temperings corresponds to not less than HRC59, not less than HRC60, and not less than HRC62 respectively.

[0066] Among them, by controlling the ratio of P / S, the percentage of harmful elements such as S and P can be minimized. The purpose of the three temperings is that due to the high content of alloy elements in the knife ring 6 of the present invention, the residual austenite content in the full-phase structure after quenching is high and the hardness is low. The first tempering after quenching can promote the decomposition of part of the austenite and temper the quenched martensite. During the first tempering cooling process, part of the undecomposed austenite will be transformed into secondary martensite; the second tempering is the tempering of the secondary martensite and further promotes the decomposition of austenite, reducing the austenite content; the third tempering can make the austenite content reach a lower level, improve the material hardness and organizational stability, the metallographic structure is martensite, and the hardness distribution is uniform.

[0067] The knife ring 6 obtained by the present invention has been tested and the standard U-shaped pendulum impact measurement of 10*10*55: 1) the overall hardness is HRC58-59, aku2=28J, and the impact toughness is 35J / cm 2 ; 2) Overall hardness HRC60-62, aku2=14.75J, impact toughness: 17.8125J / cm 2 .

[0068] It should be noted that 6Cr4Mo2W2V, which is close to the composition of the present invention, is a high alloy die steel, which contains 1.8% to 2.2% W, 0.8% to 1.2% V, 2.2% to 2.6% Mo, contains relatively high chromium, molybdenum and tungsten, has good hardenability, wear resistance and toughness, and is used in the case of high rock compressive hardness. However, the composition of the present invention contains 0.45% to 0.56% W, 0.7% to 0.85% V, 0.9% to 1.5% Mo, and 0.085% to 0.096% Cu. Compared with 6Cr4Mo2W2V, the composition ratio of the present invention is quite different. The possible reason is that the addition of Cu element reduces the usage content of chromium, molybdenum and tungsten without reducing the overall Rockwell hardness and impact toughness.

[0069] In the present invention, the ultra-fine processing of forged circles includes: heating and heat preservation at 1050°C for 3 hours, water quenching and air cooling, repeated alternating operations, water quenching time and water out of water air cooling time are carried out according to the diameter and length of the forged circle, and the water quenching time and the water out of water air cooling time are circulated in sequence until the air cooling temperature after the last water out is 150°C-200°C, and then immediately transferred to a trolley furnace set at 920°C, heated and heat-insulated, so that the whole is heated evenly, and then heat-insulated for 5-7 hours, and then cooled to about 765°C-720°C with the furnace, and after heat preservation for 6-7 hours, cooled to 350°C with the furnace and taken out of the furnace, and the steps of secondary refinement are the same as above.

[0070] Furthermore, the multi-directional forging includes: multi-directional forging temperature, initial forging temperature 1130-1150°C, final forging temperature 900±10°C, reduction rate gradually reduced from 40%-30%-20%-10%-5%, and stabilizing the thermoplastic.

[0071] Furthermore, the composite heat treatment is a carbonitriding composite heat treatment process, the carbonitriding layer has a depth of 1.1-1.3 mm and a strength of the carburizing layer, and the carbonitriding layer is carried out at a temperature of 850° C.-870° C., which can improve the wear resistance and contact fatigue resistance of the cutter ring 6 .

[0072] The specific spheroidizing annealing includes: heating the knife ring 6 to 880-900° C. and then cooling it to 750-760° C. with the furnace, keeping it warm for 1 hour, heating it to 880-900° C. again, and then cooling it to 750-760° C. with the furnace and keeping it warm.

[0073] Combination Figures 2 to 5 As shown, the heavy shield 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.

[0074] Among them, Figure 2In the figure, 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; an upper tapered roller bearing 2 and a lower tapered roller bearing 3 are sleeved on the cutter shaft 1, and the two sets of tapered roller bearing inner sleeves are hot-mounted 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; wherein 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, and when the two sets of tapered roller bearings are installed and pre-tightened, the elastic performance of the spacer ring 4 is used to adjust the clearance of the tapered roller bearings to achieve the normal required pre-tightening force.

[0075] The starting torque of the hob is mainly achieved by adjusting the clearance size between the outer rings of the two sets of tapered roller bearings and the inner ring cage rollers. Since the position of the outer ring of the bearing is fixed, the clearance size is mainly achieved by adjusting the height of the spacer ring between the inner rings of the two bearing cage rollers. The accessories of the hob, such as the cutter hub, cutter shaft, end cover, bearing, floating seal, etc., which are related to the torque size, are all machined products. The dimensional tolerances of each accessory cannot be completely consistent, and the dimensional accuracy after assembly belongs to the cumulative accuracy. Therefore, the clearance size adjustment of the bearing often needs to be configured separately for each hob, that is, the bearing spacer ring is specially configured; the current method of adjusting the height of the spacer ring is to select a spacer ring of a certain height and insert it into the cutter shaft for complete pre-assembly, and then measure the actual torque. According to the measured torque, the spacer ring is thickened or thinned by 0.5mm step size each section. Repeated trial assembly of the hob can reach or approach the process set torque.

[0076] It should be noted that, in this embodiment, the elastic spacer ring 4 is made of high-quality spring steel (such as 60Si2Mn). Figure 5 As shown, its profile shape is H-shaped. What surprised the inventor is that the upper tapered roller bearing and the lower tapered roller bearing are both 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 use analysis, it is found that under the premise of ensuring that the upper tapered roller bearing and the lower tapered roller bearing are on the upper end cover and the lower end cover, the H-shaped elastic spacer ring can adjust the preload force, thereby adjusting the clearance of the upper tapered roller bearing and the lower tapered roller bearing, and according to different geological requirements, the configuration can achieve a reasonable hob starting torque and rotation torque.

[0077] Furthermore, the manufacturing process of the elastic spacer ring 4 is as follows: steel pipe cutting - rough turning - heat treatment and tempering: quenching heating temperature 870°C, heat preservation for 2 hours, oil quenching, tempering temperature 480°C, tempering time 3 hours, furnace water cooling. The mechanical properties are as follows:

[0078]

[0079] exist Figure 2In the embodiment, 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 outer rings of the upper tapered roller bearing 2 and the lower tapered roller bearing 3 are heat-fitted on the cutter hub 5 by the cutter ring 6, 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.

[0080] like Figure 2 and Figure 3 As shown, a knife ring 6 is sleeved on the outer circumferential direction of the knife hub 5, and a retaining ring 7 is provided on one side of the knife ring 6, and the retaining ring 7 is fixed to the knife hub 5; the blade angle of the knife ring 6 is 16°, and the knife ring 6 adopts an interference fit, and is generally heated to 100-200°C and installed on the knife body. The retaining ring 7 can be two semicircular rings, which are inserted into the groove of the knife hub 5 and then welded into a whole ring.

[0081] like Figure 2 , Figure 3 and Figure 4 As shown, the upper cover assembly 8 and the lower cover assembly 9 are arranged at the axial ends of the knife 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. The structures of the upper floating seal 10 and the lower floating seal 11 are both structures disclosed in the prior art.

[0082] Combination Figure 2 and Figure 3 The upper cover assembly 8 includes 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-rings A8-6; the upper end cover 8-1 is pre-tightened at the large end face of the upper tapered roller bearing 2 with the cutter shaft 1 by an internal thread, and an O-ring A8-6 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 during the pre-tightening of the upper tapered roller bearing 2 to perform end face sealing; the upper end cover 8-1 is pre-tightened at the large end face of the upper tapered roller bearing 2 with the cutter shaft 1 by an internal thread, and the upper tapered roller bearing 2, the lower tapered roller bearing 3 and the middle elastic spacer ring 4 are synchronously pre-tightened to adjust the surrounding rock strength corresponding to the hob torque.

[0083] In this embodiment, if Figure 3As shown, 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 face between the upper oil seal bracket 8-2 and the cutter hub 5 is sealed by two O-rings A8-6; the upper oil seal bracket 8-2 is made of 42CrMo quenched and tempered parts, finely machined, and then subjected to a 0.7mm nitriding process on the surface, or the quenched and tempered parts are used for rough turning of the outer bevel and then induction hardening is performed to improve the surface wear resistance, and then the internal dimensions are finely machined to complete the designed dimensions.

[0084] Among them, 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 during the assembly process, which enhances the sealing effect and blocks the erosion of mud and sand to the maximum extent without affecting the starting torque; an O-ring A8-6 is also added between the two to seal under the upper sealing dust ring 8-4.

[0085] Furthermore, the roller cutter of the present invention is used for underground excavation where there is a large amount of mud and sand. The L-shaped upper sealing dust ring 8-4 is made of a polymer super 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 5, strictly prevent the invasion of mud and sand particles on the cutter hub 5, further protect the upper floating seal and the upper tapered roller bearing 2 in the cutter hub 5 for safe use, and extend the service life of the heavy-duty roller cutter, which has practical significance.

[0086] In order to prevent the loosening of the threads of the upper end cover 8-1 from affecting the overall preload of the upper tapered roller bearing 2, Figure 2 In the process, 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 cutter shaft 1 for peripheral groove welding, and is positioned on the cutter shaft 1 and the upper end cover 8-1 for welding stop.

[0087] Combination Figure 3 As shown, 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, which automatically discharges the internal pressure when the internal pressure of the cutter hub 5 is greater than the external pressure by 3 bar, thereby balancing the internal pressure of the cutter hub 5 and protecting the safe use of the floating seal inside the cutter hub 5.

[0088] Combination Figure 2 and Figure 4As shown, 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 a plurality of O-rings B9-5; the bearing support seat 9-1 is heat-installed at the bottom of the knife 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 B9-5; the bearing support seat 9-1 and the inner ring of the lower tapered roller bearing 3 are sealed with an O-ring B9-5, 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, and an O-ring B9-5 is configured at the end face contact portion.

[0089] 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, the lower end cover 9-2 and the lower oil seal bracket 9-3 can be conveniently and quickly disassembled when the tool is repaired, and can be quickly disassembled and assembled, changing the disadvantages caused by the limitation that the end cover 9-2 and the lower floating seal 11 can only be removed by pressing down the cutter shaft 1: on the one hand, the cutter shaft 1 and the tapered roller bearing inner sleeve are pressed out and pressed in many times, and the interference fit is gradually reduced due to wear, and the pre-tightening force is not high, resulting in axial slippage of the tapered roller bearing under the high-load rolling of the hob. After a long time, the hob cutter ring 6 is eccentrically worn and the rollers of the inner sleeve of the tapered roller bearing are abnormally worn. On the other hand, the combined design and assembly method of the upper and lower end covers 9-2 are beneficial to the hob while ensuring normal rolling and rock breaking, and can quickly assemble and quickly disassemble to analyze the internal situation of the hob hub 5, and quickly repair and replace the lower floating seal 11 and various seals.

[0090] In this embodiment, if Figure 4 As shown, 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 blade hub 5 is sealed by two O-rings B9-5.

[0091] Furthermore, the lower oil seal bracket 9-3 is made of 42CrMo tempered parts, finely machined, and then subjected to a 0.7mm nitriding process on the surface, or the tempered parts are roughly turned into shape and then the outer bevel is induction hardened to improve the surface wear resistance, and then the internal dimensions are finely machined to complete the designed dimensions.

[0092] Further, such as Figure 4 As shown, the lower end cover 9-2 and the lower oil seal bracket 9-3 are subjected to static friction gap step sealing by the lower sealing dust ring 9-4 during the assembly process, which enhances the sealing effect and blocks the erosion of mud and sand to the maximum extent without affecting the starting torque; an O-ring B9-5 is also added between the two to seal above the lower sealing dust ring 9-4.

[0093] 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 can better stabilize the sealing performance of the cutter hub 5, strictly prevent the invasion of mud and sand particles on the cutter hub 5, and further protect the lower floating seal 11 and the lower tapered roller bearing 3 in the cutter hub 5 for safe use, which has practical significance for extending the service life of heavy-duty hobs.

[0094] Example 1

[0095] The main metal elements of the heavy shield hob cutter ring 6 of this embodiment are as follows: C: 0.56%, Si: 0.68%, Mn: 0.35%, Cr: 5%, Mo: 1.5%, W: 0.45%, V: 0.7%, P / S: 0.013, Ni: 2.8%, Cu: 0.096%, and the rest is Fe; the heat treatment process includes: diffusing the steel ingot obtained by smelting the metal elements at 1250°C, multi-directional forging, repeatedly upsetting and drawing when opening the blank Round steel, forging round ultra-fine + blanking forging and rolling ring into billet + secondary refinement + spheroidizing annealing + composite heat treatment after rough machining + vacuum quenching and tempering heat treatment; in order to prevent surface decarburization of the knife ring 6 during quenching heating, the knife ring 6 is vacuum quenched: 1030℃*5h; the knife ring 6 after quenching should be heat treated in time, 3 tempering heat treatments: 350℃*3h*2 times; 535℃*5h*1 time, the overall hardness of the 3 temperings corresponds to HRC59, HRC60, and HRC62 respectively.

[0096] The ultra-fine processing of forged circles includes: heating and heat preservation at 1050℃ for 3 hours, water quenching and air cooling, repeated alternating operations, water quenching time and water out of water air cooling time according to the diameter and length of the forged circle, and cycled in sequence until the last water out of water and the air cooling temperature is 150℃, and then immediately transferred to the trolley furnace set at 920℃, heated and heat-insulated, so that the whole is heated evenly, and then heat-insulated for 5 hours, and then cooled to about 720℃ with the furnace, and after heat preservation for 6 hours, cooled to 350℃ with the furnace and taken out of the furnace, and the steps of secondary refinement are the same as above. The samples obtained after the above steps have a grain size of 8.5. Figure 1 shown.

[0097] Furthermore, the multi-directional forging includes: multi-directional forging temperature, initial forging temperature 1130°C, final forging temperature 900°C, reduction rate gradually reduced from 40%-30%-20%-10%-5%, and stabilizing the thermoplastic.

[0098] Furthermore, the composite heat treatment is a carbonitriding composite heat treatment process, the carbonitriding layer has a depth of 1.1 mm and a strength, and the carbonitriding layer is carried out at a temperature of 850° C., which can improve the wear resistance and contact fatigue resistance of the cutter ring 6 .

[0099] Specific spheroidizing annealing: the knife ring 6 is heated to 880°C and then cooled to 750°C in the furnace. After being kept warm for 1 hour, it is heated to 880°C again and then cooled to 750°C in the furnace and kept warm.

[0100] The obtained knife ring is tested and the results are as follows Fig.12 As shown in the figure, install the knife ring on the roller and test it. The results are as follows Figure 9-11 As shown, the heavy-duty shield cutter ring has the best mechanical properties and the wear resistance of the ultra-high permeability layer, which is fully suitable for the technical configuration requirements of large shield, large diameter and high-load cutters.

[0101] Example 2

[0102] The main metal elements of the heavy shield cutter ring 6 of this embodiment are as follows: C: 0.48%, Si: 0.68%, Mn: 0.35%, Cr: 5%, Mo: 0.9%, W: 0.45%, V: 0.85%, P / S: 0.013, Ni: 3.6%, Cu: 0.096%, and the rest is Fe; the heat treatment process includes: smelting the metal elements to obtain the steel ingot at a high temperature of 1250°C Diffusion and multi-directional forging, repeated upsetting and drawing into round steel when opening the blank, forging round ultra-fine + blanking forging and rolling ring into blank + secondary refinement + spheroidizing annealing + composite heat treatment after rough machining + vacuum quenching and tempering heat treatment; in order to prevent surface decarburization of the knife ring 6 during quenching heating, the knife ring 6 is vacuum quenched: 1030℃*4h; the knife ring 6 after quenching should be heat treated in time, 3 tempering heat treatments: 350℃*3h*2 times; 530℃*5h*1 time.

[0103] Among them, the ultra-fine processing of the forged circle includes: heating and heat preservation at 1050°C in steps for 3 hours, water quenching and air cooling, repeated alternating operations, water quenching time and water out of air cooling time are carried out according to the diameter and length of the forged circle, and the water quenching time and the water out of air cooling time are circulated in sequence until the air cooling temperature after the last water out is 180°C, and then it is immediately transferred to a trolley furnace set at 920°C, heated and heat-insulated to make the whole heated evenly, and then heat-insulated for 6 hours, and then cooled to about 740°C with the furnace. After heat preservation for 6 hours, it is cooled to 350°C with the furnace and taken out of the furnace. The steps of secondary refinement are the same as above.

[0104] Furthermore, the multi-directional forging includes: multi-directional forging temperature, initial forging temperature 1140°C, final forging temperature 910°C, reduction rate gradually reduced from 40%-30%-20%-10%-5%, and stabilizing the thermoplastic body.

[0105] Furthermore, the composite heat treatment is a carbonitriding composite heat treatment process, the carbonitriding layer has a depth of 1.2 mm and a strength of the carburizing layer, and the carbonitriding layer is carried out at a temperature of 860° C., which can improve the wear resistance and contact fatigue resistance of the cutter ring 6 .

[0106] Specific spheroidizing annealing: the knife ring 6 is heated to 890°C and then cooled to 755°C with the furnace. After being kept warm for 1 hour, it is heated to 890°C again and then cooled to 755°C with the furnace and kept warm.

[0107] Example 3

[0108] The main metal elements of the heavy shield hob cutter ring 6 of this embodiment are as follows: C: 0.48%, Si: 0.68%, Mn: 0.47%, Cr: 5.6%, Mo: 0.9%, W: 0.56%, V: 0.7%, P / S: 0.013, Ni: 2.8%, Cu: 0.085%, and the rest is Fe; its heat treatment process includes: diffusing the steel ingot obtained by smelting the metal elements at 1250°C and multi-directional forging, repeatedly upsetting and drawing into round steel when opening the blank, forging round ultra-fine + blanking forging and rolling ring into blank + secondary refinement + spheroidizing annealing + composite heat treatment after rough machining + vacuum quenching and tempering heat treatment; the cutter ring 6 is vacuum quenched: 1030°C*5h; the cutter ring 6 after quenching should be heat treated in time, 3 tempering heat treatments: 350°C*3h*2 times; 530-℃*5h*1 time.

[0109] Among them, the ultra-fine processing of the forged circle includes: heating and heat preservation at 1050°C in steps for 3 hours, water quenching and air cooling, repeated alternating operations, water quenching time and water out of air cooling time are carried out according to the diameter and length of the forged circle, and the water quenching time and the water out of air cooling time are circulated in sequence until the air cooling temperature after the last water out is 200°C, and then it is immediately transferred to a trolley furnace set at 920°C, heated and heat-insulated to make the whole heated evenly, and then heat-insulated for 7 hours, and then cooled to 765°C with the furnace. After heat preservation for 7 hours, it is cooled to 350°C with the furnace and taken out of the furnace. The steps of secondary refinement are the same as above.

[0110] Furthermore, the multi-directional forging includes: multi-directional forging temperature, initial forging temperature 1150°C, final forging temperature 900°C, reduction rate gradually reduced from 40%-30%-20%-10%-5%, and stabilizing the thermoplastic.

[0111] Furthermore, the composite heat treatment is a carbonitriding composite heat treatment process, the carbonitriding layer has a depth of 1.3 mm and a strength of the carburizing layer, and the carbonitriding layer is carried out at a temperature of 870° C., which can improve the wear resistance and contact fatigue resistance of the cutter ring 6 .

[0112] Specific spheroidizing annealing: the knife ring 6 is heated to 900°C and then cooled to 760°C in the furnace. After being kept warm for 1 hour, it is heated to 900°C again and then cooled to 760°C in the furnace and kept warm.

[0113] The present invention and its embodiments are described schematically above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A heavy shield cutter ring (6), characterized in that: The knife ring (6) has the following main metal elements in percentage by mass: C: 0.48% to 0.56%, Si: 0.68% to 0.78%, Mn: 0.35% to 0.47%, Cr: 5% to 5.6%, Mo: 0.9% to 1.5%, W: 0.45% to 0.56%, V: 0.7% to 0.85%, P / S: 0.013, Ni: 2.8% to 3.6%, Cu: 0.085% to 0.096%, and the rest are Fe; its heat treatment process comprises: diffusing the steel ingot obtained by smelting the metal element at a high temperature of 1250°C, multi-directional forging, repeatedly upsetting and drawing into round steel when blanking, forging round ultra-fine + blanking forging and ring rolling into blank + secondary refinement + spheroidizing annealing + composite heat treatment after rough machining + vacuum quenching and tempering heat treatment; vacuum quenching of the knife ring (6): 1030°C*(3-5h); 3 tempering heat treatments: 350°C*3h*2 times, (530-540)°C*5h*1 time.

2. The heavy shield cutter ring (6) according to claim 1, characterized in that: The forging round ultrafine process includes: heating to 1050°C for 3 hours, water quenching and air cooling, repeated alternating operations, and circulating in sequence until the air cooling temperature is 150°C-200°C after the last water discharge, and then immediately transferred to a trolley furnace set at 920°C, heating and heat preservation so that the whole is heated evenly, and then heat preservation for 5-7 hours, and then cooled to 765°C-720°C with the furnace, and after heat preservation for 6-7 hours, cooled to 350°C with the furnace and taken out of the furnace.

3. The heavy shield cutter ring (6) according to claim 2, characterized in that: The multi-directional forging includes: the initial forging temperature of the multi-directional forging is 1130-1150° C., the final forging temperature is 900±10° C., and the reduction rate is gradually reduced from 40%-30%-20%-10%-5%.

4. The heavy shield cutter ring (6) according to claim 3, characterized in that: The composite heat treatment is a carbonitriding composite heat treatment process, the depth of the infiltration layer is 1.1-1.3 mm, and the carbonitriding is performed at a temperature of 850° C.-870° C.

5. A heavy shield disc 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); 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 cutting ring (6) is sleeved on the outer circumferential direction of the cutting hub (5), a retaining ring (7) is provided on one side of the cutting ring (6), and the retaining ring (7) is fixed to the cutting hub (5); the cutting ring (6) is a heavy shield hob cutting ring (6) as claimed in any one of claims 1 to 4; and an upper cover assembly (8) and a lower cover assembly (9) arranged at the axial ends of the knife 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).

6. The heavy shield disc cutter according to claim 5, characterized in that: The material of the spacer ring (4) is spring steel, and its profile shape is H-shaped.

7. The heavy shield disc cutter according to claim 5, 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.

8. The heavy shield disc cutter according to claim 7, 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).

9. The heavy shield disc cutter according to claim 5, 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).

10. A TMB shield equipment having the heavy shield disc cutter according to any one of claims 5 to 9.

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