A wear-resistant cutter ring of a shield cutter

Abstract

The utility model discloses a kind of shield cutter wear-resistant cutter ring, belong to shield cutter technical field.A kind of shield cutter wear-resistant cutter ring of the utility model, including wear-resistant alloy layer, strong tough alloy steel layer and shock-absorbing buffer layer connected in order from outside to inside, the strong tough alloy steel layer is close to bridge site and is equipped with sequentially connected first circular arc transition, bevel and gentle section, and middle stress groove is set in gentle section middle part.A kind of shield cutter wear-resistant cutter ring of the utility model, adopt tungsten carbide coating as wear-resistant alloy layer, significantly improve the wear resistance of cutter ring surface, prolong service life, by gradient transition design and the middle stress groove on gentle section, effectively disperses and absorbs stress, reduces the generation and extension of crack, the design of double-layer buffer structure and gradual change buffer zone, ensure that cutter ring can self-adapting adjustment deformation under complex geological conditions, reduce vibration transmission to cutter hub, protect mechanical equipment from damage.

Description

Technical Field

[0001] This utility model relates to the field of shield tunnel cutterhead technology, and more specifically, to a wear-resistant cutterhead ring for shield tunnel cutters. Background Technology

[0002] Traditional tunnel boring machine (TBM) cutterheads face three major technical challenges when operating under complex geological conditions: 1) It is difficult to balance wear resistance and impact toughness, leading to premature cutterhead failure; 2) Uneven wear and uneven wear are prone to occur in strata with alternating soft and hard surfaces; 3) Stress concentration causes rapid crack propagation. Existing solutions mostly use single materials or simple composite structures, which cannot simultaneously meet the requirements of high strength, high wear resistance, and excellent impact resistance. Although some improved designs attempt to alleviate stress through slotting, problems such as unreasonable slot structure and limited buffering effect exist, resulting in no significant improvement in the overall performance of the cutterhead. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a wear-resistant cutter ring for tunnel boring machines to solve the above-mentioned deficiencies.

[0004] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0005] This utility model discloses a wear-resistant cutter ring for tunnel boring machines, comprising a wear-resistant alloy layer, a tough alloy steel layer, and a shock-absorbing buffer layer connected sequentially from the outside to the inside. The tough alloy steel layer has a first arc transition, a slope, and a gentle section connected sequentially near the bridging part. An intermediate stress groove is provided in the middle of the gentle section. The shock-absorbing buffer layer has a second arc transition that wraps around the first arc transition. The inner ring of the shock-absorbing buffer layer has an inner stress groove that nests and cooperates with the intermediate stress groove.

[0006] Preferably, the wear-resistant alloy layer accounts for 20%-30% of the total thickness of the cutter ring, the tough alloy steel layer accounts for 50%-60% of the total thickness of the cutter ring, and the shock-absorbing buffer layer accounts for 10%-20% of the total thickness of the cutter ring.

[0007] Preferably, the inner stress groove has a parabolic cross-section, the groove opening width is greater than the groove bottom width, the groove depth gradually decreases from the middle to the edge, and the groove opening edge is rounded.

[0008] Preferably, auxiliary buffer holes are provided at equal intervals at the bottom of the intermediate stress groove, and the diameter of the auxiliary buffer holes is 1 / 5 to 1 / 3 of the width of the intermediate stress groove.

[0009] Preferably, the auxiliary buffer hole is filled with an elastic damping rod.

[0010] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0011] This utility model discloses a wear-resistant cutter ring for tunnel boring machines. It employs a tungsten carbide coating as the wear-resistant alloy layer, significantly improving the wear resistance of the cutter ring surface and extending its service life. Through a gradient transition design and intermediate stress grooves on the smooth sections, stress is effectively dispersed and absorbed, reducing the generation and propagation of cracks. The double-layer buffer structure and the design of the gradual buffer zone ensure that the cutter ring can adaptively adjust its deformation under complex geological conditions, reducing vibration transmission to the cutter hub and protecting mechanical equipment from damage. The elastic damping rods within the auxiliary buffer holes suppress the initiation of vibration-induced microcracks, improving the safety and reliability of the cutter ring under extreme conditions. Attached Figure Description

[0012] Figure 1 This is an overall structural diagram of the wear-resistant cutter ring for tunnel boring machines according to this utility model;

[0013] Figure 2 This is a cross-sectional view of the wear-resistant cutter ring of the shield tunnel cutter of this utility model;

[0014] Figure 3 This is a partial cross-sectional view of the wear-resistant cutter ring of the shield tunnel cutterhead according to this utility model;

[0015] Figure 4 This is an enlarged view of section A of this utility model.

[0016] In the diagram: 1. Wear-resistant alloy layer; 2. High-strength alloy steel layer; 21. First arc transition; 22. Sloping surface; 23. Gentle section; 24. Intermediate stress groove; 241. Auxiliary buffer hole; 25. Elastic damping rod; 3. Shock-absorbing buffer layer; 31. Second arc transition; 32. Inner stress groove. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings.

[0019] Combination Figures 1-4This utility model discloses a wear-resistant cutter ring for tunnel boring machines, comprising a wear-resistant alloy layer 1, a strong and tough alloy steel layer 2, and a shock-absorbing buffer layer 3 connected sequentially from the outside to the inside. The wear-resistant alloy layer 1 is made of micron-sized tungsten carbide and titanium carbide materials, with a thickness of 20%-30% of the total thickness of the cutter ring. It is responsible for direct contact with the rock and soil and providing wear resistance. The strong and tough alloy steel layer 2 is made of 42CrMo material, with a thickness of 50%-60%. It bears the main load and inhibits crack propagation. The shock-absorbing buffer layer 3 is made of metal rubber, with a thickness of 10%-20%. It is connected to the cutter hub through an interference fit and absorbs vibration impact.

[0020] Specifically, a first arc transition 21 is provided at the connection point of the strong and tough alloy steel layer 2 near the bridging part. The first arc transition 21 is connected to a gentle section 23 through an inclined surface 22. An intermediate stress groove 24 is provided in the middle of the gentle section 23. The cooperation between the inclined surface 22 and the gentle section 23 forms a gradient transition, which further homogenizes the stress distribution and prevents cracks from initiating at the connection point. The introduction of the intermediate stress groove 24 enables the middle area of ​​the strong and tough alloy steel layer 2 to have local elastic deformation capability, which can absorb high-frequency impact energy in alternating soft and hard strata. The inclined surface 22 increases the distance between the gentle section 23 and the inner wall of the shock-absorbing buffer layer 3, and increases the thickness of the shock-absorbing buffer layer 3 in the middle area of ​​the strong and tough alloy steel layer 2. The increased thickness of the shock-absorbing buffer layer 3 enhances the overall buffering effect, especially reducing the vibration amplitude transmitted to the cutterhead when tunneling in hard rock.

[0021] More specifically, a second arc transition 31 is provided near the first arc transition 21 in the shock-absorbing buffer layer 3. The second arc transition 31 wraps around the first arc transition 21 and connects directly to the bridging part. The second arc transition 31 wraps around the first arc transition 21 to form a double-layer buffer structure, so that the impact load of the bridging part is absorbed step by step and stress change is reduced. At the same time, an inner stress groove 32 is provided near the middle stress groove 24 in the shock-absorbing buffer layer 3. The inner stress groove 32 is attached to the inner wall of the middle stress groove 24. The inner stress groove 32 and the middle stress groove 24 are nested to form a cooperative deformation zone, which provides additional elastic deformation space under extreme loads and avoids overall brittle fracture. The cross-section of the inner stress groove 32 is parabolic, the groove opening width is greater than the groove bottom width, and the groove depth gradually decreases from the middle of the cutter ring to the two sides, forming a gradual buffer zone, so that the cutter ring can adaptively adjust the deformation in the alternating soft and hard strata. The groove opening edge is rounded to disperse the edge stress.

[0022] It should be noted that the bottom of the intermediate stress groove 24 is provided with auxiliary buffer holes 241 at equal intervals. The auxiliary buffer holes 241 are blind holes, and the width of the blind holes is 1 / 5 to 1 / 3 of the groove width of the auxiliary buffer holes 241. This avoids weakening the overall strength of the cutter ring. The auxiliary buffer holes 241 are filled with elastic damping rods 25. The elastic damping rods 25 filled in the holes can suppress the initiation of microcracks caused by vibration. The auxiliary buffer holes 241 and the intermediate stress groove 24 work together to form a composite buffer system of "main groove + microhole". This allows the impact energy to be absorbed step by step. The design of the elastic damping rods 25 is to undergo compression deformation under extreme impact, further consuming energy and avoiding crack propagation caused by hard collision. This makes the stress distribution at the bottom of the groove more uniform and eliminates the local high stress points of the traditional single groove.

[0023] The wear-resistant cutterhead ring for tunnel boring machines is manufactured using centrifugal casting technology. The centrifugal force generated by a rotating mold causes molten metal to solidify in layers according to density within the mold cavity, resulting in a three-layer composite structure: a wear-resistant alloy layer, a strong and tough alloy steel layer, and a shock-absorbing buffer layer, formed sequentially from the outside in. Centrifugal force ensures a uniform distribution of high-density micron-sized carbides (WC, TiC) on the outer layer, achieving integrated molding of graded functional materials. The specific process steps are as follows:

[0024] Mold design and preheating:

[0025] High-temperature alloy steel molds are used, and the cavity structure needs to accurately replicate the final shape of the cutter ring, including the convex and concave features of the first arc transition 21, the inclined surface 22, the gentle section 23, the intermediate stress groove 24 and the inner stress groove 32. The mold is preheated to 300-400℃ and sprayed with boron nitride-based centrifugal casting release agent.

[0026] Smelting and casting:

[0027] Outer wear-resistant alloy layer 1 smelting: High carbon steel matrix is ​​smelted in a medium frequency induction furnace. After heating to 1550-1600℃, micron-sized tungsten carbide (WC) and titanium carbide (TiC) powders with a particle size of 5-15μm are added. The amount added is 30%-40% of the matrix mass. Mechanical stirring and argon gas protection are used to prevent oxidation.

[0028] Mid-layer strong and tough alloy steel layer 2 smelting: Simultaneous smelting of 42CrMo steel, heating to 1500-1550℃, refining and removing slag, and then holding at the temperature for later use;

[0029] Material preparation for inner shock-absorbing buffer layer 3: Pre-form the metal rubber into a ring-shaped blank and preheat it to 500℃ for later use.

[0030] Centrifugal casting and molding;

[0031] First stage: The wear-resistant alloy molten liquid is poured into a high-speed rotating mold at a speed of 800-1200 rpm. The centrifugal force makes the high-density WC-TiC composite layer adhere tightly to the cavity wall and solidify to form a wear-resistant alloy layer 1 with a thickness of 20%-30% of the total thickness of the cutter ring.

[0032] Second stage: After the wear-resistant alloy layer 1 has initially solidified, pour 42CrMo melt immediately, adjust the speed to 600-800 rpm, and centrifugal force to achieve metallurgical bonding between the strong and tough alloy steel layer 2 and the wear-resistant alloy layer 1. Its thickness accounts for 50%-60%. Through controlled cooling technology, ensure that the intermediate stress groove 24 area achieves fine grain strengthening.

[0033] Third stage: After the tough alloy steel layer 2 solidifies, the machine is stopped. The preheated metal rubber ring is pressed into the inner wall of the middle layer with an interference fit. The residual heat is used to achieve hot assembly, forming a shock-absorbing buffer layer 3 with a thickness of 10%-20%. This step ensures that the second arc transition 31 can tightly wrap the first arc transition 21.

[0034] Heat treatment and finishing:

[0035] Gradient quenching: The casting is oil quenched at 910℃ and tempered at medium temperature on the outer layer to achieve high hardness of wear-resistant alloy layer 1 and high strength and toughness of alloy steel layer 2.

[0036] Working process: When this cutter ring is working, the wear-resistant alloy layer 1 first contacts the rock and soil, and its tungsten carbide coating provides excellent wear resistance. As the excavation depth increases, when encountering hard rock, the tough alloy steel layer 2 bears the main load. Through the design of the first arc transition 21, the inclined surface 22 and the gentle section 23, the stress distribution is more uniform, preventing cracks from initiating at the connection. The intermediate stress groove 24 allows local elastic deformation and absorbs high-frequency impact energy. When encountering alternating soft and hard strata or extreme loads, the shock-absorbing buffer layer 3 plays a role. The second arc transition 31 wraps around the first arc transition 21 to form a double-layer buffer structure, absorbing the impact load step by step. The inner stress groove 32 works in conjunction with the intermediate stress groove 24 to provide additional elastic deformation space in extreme cases, avoiding overall brittle fracture. The elastic damping rod 25 in the auxiliary buffer hole 241 further dissipates vibration energy through compression deformation. The parabolic groove with gradually changing depth and the double-layer arc transition structure ensure uniform stress distribution and avoid local stress concentration.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0038] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A wear-resistant cutter ring for tunnel boring machines, comprising a wear-resistant alloy layer (1), a strong and tough alloy steel layer (2), and a shock-absorbing buffer layer (3) connected sequentially from the outside to the inside, characterized in that, The strong and tough alloy steel layer (2) is provided with a first arc transition (21), a slope (22) and a flat section (23) connected in sequence near the bridging part. A middle stress groove (24) is provided in the middle of the flat section (23). A second arc transition (31) is provided on the shock-absorbing buffer layer (3) to wrap the first arc transition (21). An inner stress groove (32) is provided in the inner circle of the shock-absorbing buffer layer (3) to nest and cooperate with the middle stress groove (24).

2. The wear-resistant cutter ring for tunnel boring machines according to claim 1, characterized in that, The wear-resistant alloy layer (1) accounts for 20%-30% of the total thickness of the cutter ring, the tough alloy steel layer (2) accounts for 50%-60% of the total thickness of the cutter ring, and the shock-absorbing buffer layer (3) accounts for 10%-20% of the total thickness of the cutter ring.

3. The wear-resistant cutter ring for tunnel boring machines according to claim 1, characterized in that, The inner stress groove (32) has a parabolic cross section, with the groove opening width being greater than the groove bottom width, and the groove depth gradually decreasing from the middle to the edge. The groove opening edge is rounded.

4. The wear-resistant cutter ring for tunnel boring machines according to claim 1, characterized in that, The intermediate stress groove (24) has auxiliary buffer holes (241) at equal intervals at the bottom of the groove. The diameter of the auxiliary buffer holes (241) is 1 / 5 to 1 / 3 of the width of the intermediate stress groove (24).

5. The wear-resistant cutter ring for tunnel boring machines according to claim 4, characterized in that, The auxiliary buffer hole (241) is filled with an elastic damping rod (25).

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