Inserted hob for optimizing alloy tooth surface structure

Abstract

The utility model discloses an inserted tooth hob with optimized alloy tooth surface structure, which relates to the technical field of inserted tooth hobs and comprises a bearing and a cutter shaft, a cutter body is sleeved on the periphery of the bearing, a cutter ring is sleeved on the periphery of the cutter body, and alloy teeth with optimized surfaces are uniformly arranged on the periphery of the cutter ring. End covers are arranged on the two sides of the cutter body, and the cutter shaft is sleeved with the end covers and the bearings. The alloy teeth are provided with the convex surface structures, and the size, the direction and the fluctuation degree of stress of the alloy teeth can be adjusted by designing different sizes and numbers of polygons, so that the inserted tooth hob using the alloy teeth has the capability of adapting to different geological working conditions, and the service life of the inserted tooth hob is prolonged. Therefore, the problems that when the hobbing cutter works, due to the fact that the hobbing cutter cannot adapt to the geological environment, the load is too large, vibration is too violent, and alloy teeth are prone to breakage are solved.

Description

Technical Field

[0001] This utility model relates to the field of toothed hobbing technology, and in particular to a toothed hobbing tool with optimized alloy tooth surface structure. Background Technology

[0002] Full-face tunnel boring machines are large-scale mechanical equipment used for underground space development. They have a fast tunneling speed, do not require blasting operations, and cause little disturbance to surface buildings. They are currently the preferred solution for the construction of challenging underground facilities such as urban subway tunnels, cross-river and cross-sea tunnels, and pumped storage power station water diversion tunnels.

[0003] Cutting rollers are a key component for rock-breaking tunneling. Located at the very front of the full-face tunnel boring machine (MTBM), they are mounted on the cutterhead (approximately 30-60 rollers in total) and directly contact the rock mass. During operation, the hydraulic system propels the cutterhead forward, while a motor drives it to rotate around its own axis. The rollers, driven by the cutterhead, penetrate the rock, causing surface rock fragmentation and breakage along their path, allowing the MTBM to advance gradually. Therefore, the ease with which the rollers penetrate the rock and their service life are crucial factors determining the construction speed of a full-face tunnel boring machine.

[0004] Toothed cutterheads are a type of cutterhead used in full-face tunnel boring machines. Specifically, holes are drilled at fixed intervals on the outer circumference of the cutter, and alloy teeth are embedded in these holes. The tips of the alloy teeth protrude above the outer circumference of the cutter, allowing them to replace the cutter surface in contact with the rock during rock breaking. Generally, the protruding parts of the alloy teeth are spherical or wedge-shaped, resulting in a small contact area with the rock and a strong stress concentration effect. This allows them to penetrate the rock with relatively low thrust. Simultaneously, the high hardness of the alloy teeth enhances their wear resistance. Theoretically, toothed cutterheads can simultaneously achieve high rock-breaking efficiency and a long service life.

[0005] However, in practical engineering, the main failure mode of toothed hobs is alloy tooth fracture (i.e., the protruding part of the alloy tooth breaks off along the boundary between the alloy tooth and the outer peripheral surface of the hob). As can be seen from the working principle of toothed hobs described above, after the alloy tooth fractures, the toothed hob immediately loses part or all of its ability to break rocks. If it is not detected and replaced in time, there is a risk of further damage to surrounding tools and cutterhead.

[0006] The main reason for the fracture of alloy teeth in toothed hobs is the unreasonable distribution of loads acting on them. During the rock breaking process, the magnitude of the contact force on the alloy teeth first increases and then gradually decreases as the hob rolls forward. When the contact force reaches its maximum value, the direction of the contact force does not coincide with the axis of the alloy teeth, which generates a bending moment on the alloy teeth and causes them to fracture.

[0007] The fragility of alloy teeth leads to a short and highly uncertain lifespan for toothed cutters. Frequent inspection and replacement are unavoidable when using toothed cutters, preventing them from fully utilizing their advantages of low load requirements and high wear resistance. In conditions where ordinary cutters struggle to excavate, such as extremely hard rock and high ground stress, the lack of reliable toothed cutters restricts the construction speed of full-face tunnel boring machines, wastes significant manpower and resources, and substantially increases project costs. Therefore, developing a fracture-resistant toothed cutter has important engineering application significance.

[0008] In recent years, there have been some patents related to toothed hobs, but none have focused on improving the fracture resistance of the alloy teeth. For example, Chinese utility model patent CN202323369982.5, entitled "A High-Temperature Resistant and Wear-Resistant Toothed Hob," improves the wear resistance of toothed hobs through surface coating; Chinese utility model patent CN202310879465.8, entitled "An Evaluation Method for the Service Life of Toothed Hob Cutter Rings," determines the remaining service life of toothed hobs based on indicators such as the wear amount of alloy teeth and whether the alloy teeth are loose. Utility Model Content

[0009] The purpose of this invention is to provide a toothed hob with an optimized alloy tooth surface structure. By optimizing the surface structure of the metal teeth, the fracture resistance of the alloy teeth is improved. By controlling the stress state of the alloy teeth during rock crushing, the problem of easy fracture and failure of the alloy teeth in existing toothed hobs is solved, the service life of the toothed hob is extended, and the operating cost of full-face tunnel boring machines is reduced.

[0010] To achieve the above objectives, this utility model provides the following technical solution:

[0011] A toothed hob with optimized alloy tooth surface structure includes a bearing and a cutter shaft. A cutter body is sleeved on the outer periphery of the bearing, and a cutter ring is sleeved on the outer periphery of the cutter body. Surface-optimized alloy teeth are uniformly arranged on the outer periphery of the cutter ring.

[0012] The blade body is provided with end caps on both sides, and the end caps and bearings are both sleeved on the blade shaft.

[0013] In some embodiments, a blade ring positioning ring is provided at the connection between the blade body and the blade ring to constrain the movement of the blade ring.

[0014] In some embodiments, the surface of the alloy tooth is composed of multiple polygonal faces, including at least one of triangles, quadrilaterals, pentagons, and hexagons, which can change the direction of the load on the alloy tooth during rock breaking and avoid the formation of additional bending moments on the alloy tooth, thus preventing it from breaking.

[0015] In some embodiments, the alloy teeth and the cutter ring are embedded in the outer circumferential surface of the cutter ring through an interference fit.

[0016] In some embodiments, the alloy teeth are made of cemented carbide.

[0017] In some embodiments, the end cap includes a left end cap and a right end cap, which are respectively disposed on the left and right end faces of the blade body.

[0018] In some embodiments, a bearing sealing ring is provided at the connection between the end cover and the bearing, and a cutter shaft sealing ring is provided at the connection between the end cover and the cutter shaft.

[0019] In some embodiments, the system further includes a PLC controller and a sensor disposed inside the alloy tooth. The PLC controller is connected to the sensor via a wire and to a host computer via a wireless data transmission terminal. This allows for real-time monitoring of whether the alloy tooth has broken, enabling construction personnel to replace the tool promptly or develop a reasonable tool replacement and maintenance plan.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention replaces the spherical surface of traditional alloy teeth with a surface composed of multiple polygons. In this case, the maximum contact force between the alloy teeth and the rock will occur on one side of a polygon in the center of the alloy teeth. On the one hand, the sharp structure formed by the common side of two adjacent polygons increases the stress concentration effect, making the toothed hob using this alloy tooth easier to break rocks. On the other hand, the location of the maximum contact force on the alloy teeth is closer to the center of the alloy teeth, the angle between the direction of the maximum contact force and the direction of the alloy tooth axis is reduced, the maximum bending moment caused by the maximum contact force on the alloy teeth is reduced, and the risk of alloy tooth breakage is reduced.

[0022] The alloy teeth described in this invention have an outwardly convex surface structure. By designing different polygonal sizes and quantities, the magnitude, direction, and degree of force on the alloy teeth can be adjusted, enabling the toothed hob using the alloy teeth to adapt to different geological conditions. This avoids the problems of excessive load and excessive vibration caused by the hob's inability to adapt to the geological environment during operation.

[0023] The sensors and PLC controllers of this invention enable construction personnel to intuitively know the number of broken alloy teeth on the toothed hob, so as to replace the damaged toothed hobs in a timely manner and avoid the continuous use of toothed hobs with broken teeth, which could cause damage to adjacent tools or cutter head structures. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present utility model;

[0025] Figure 2 This is a cross-sectional structural diagram of Embodiment 1 of the present invention;

[0026] Figure 3 This is a schematic cross-sectional view of the alloy teeth and cutter ring in Embodiment 1 of this utility model.

[0027] Figure 4 This is a schematic diagram (pentagonal) of the alloy tooth structure of Embodiment 1 of this utility model;

[0028] Figure 5 This is a schematic diagram (triangle) of the alloy tooth structure of Embodiment 1 of this utility model;

[0029] Figure 6 This is a schematic diagram of the formation of the convex surface of the alloy tooth in Embodiment 1 of this utility model;

[0030] Figure 7 This is a schematic diagram showing the load change of the alloy teeth with optimized surface structure in Embodiment 1 of this utility model during the rock-breaking process.

[0031] Figure 8 The average contact pressure distribution on the surface of the alloy tooth after surface structure optimization in Embodiment 1 of this utility model;

[0032] Figure 9 This is a structural schematic diagram of Embodiment 2 of the present invention.

[0033] As shown in the figure:

[0034] 1. Cutter ring, 2. Bearing, 3. Cutter shaft, 4. Cutter body, 5. Right end cover, 6. Left end cover, 7. Bearing seal ring, 8. Cutter shaft seal ring, 9. Cutter ring positioning ring, 10. Alloy teeth, 11. Sensor. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0036] Example 1

[0037] Please see Figures 1-5 A toothed hob with optimized alloy tooth surface structure includes a bearing 2 and a cutter shaft 3. A cutter body 4 is sleeved on the outer periphery of the bearing 2. The outer ring of the bearing 2 is connected to the cutter body 4 by an interference fit. A cutter ring 1 is fixedly connected to the outer periphery of the cutter body 4. Alloy teeth 10 are evenly arranged on the outer periphery of the cutter ring 1.

[0038] The alloy teeth 10 are embedded in the outer circumferential surface of the cutter ring 1 through an interference fit. A cutter ring positioning ring 9 is provided at the connection between the cutter body 4 and the cutter ring 1. The cutter ring positioning ring 9 is installed in a groove on the outer circumference of the cutter body 4 to constrain the movement of the cutter ring 1.

[0039] The cutter body 4 has end caps on both sides, and both the end caps and the bearings 2 are fitted onto the cutter shaft 3. The end caps include a left end cap 6 and a right end cap 5, which are respectively installed on the left and right end faces of the cutter body 4 by bolts. A bearing sealing ring 7 is provided at the connection between the end cap and the bearing 2, and a cutter shaft sealing ring 8 is provided at the connection between the end cap and the cutter shaft 3.

[0040] The alloy tooth 10 is made of cemented carbide. The alloy tooth 10 has an optimized convex surface structure composed of multiple polygonal faces, which can change the direction of the load on the alloy tooth 10 during rock breaking, avoiding the formation of additional bending moments that could cause it to break. The polygonal faces include at least one of triangles, quadrilaterals, pentagons, and hexagons. The convex surface of the alloy tooth 10 will not have any arc shapes, but only straight lines (i.e., the sides of the polygons). This allows the maximum contact force between the alloy tooth 10 and the rock to occur on a side closest to the midpoint of the convex surface of the alloy tooth 10, reducing the angle between the direction of the maximum contact force and the axis of the alloy tooth, reducing the maximum bending moment on the alloy tooth 10, lowering the possibility of the alloy tooth 10 breaking under bending moment, extending the service life of the toothed cutter, reducing the frequency of toothed cutter replacement, and thus reducing the cost of tunnel excavation using a full-face tunnel boring machine.

[0041] like Figure 7 As shown in the finite element simulation, during the rolling process over the rock surface, the maximum contact force of the alloy tooth 10 optimized by the convex surface appears in the middle and rear of the rolling path. At this time, the axis of the alloy tooth 10 and the direction of the maximum contact force are approximately perpendicular to the rock surface, and the included angle between them is small. The bending moment of the alloy tooth 10 is low, and the risk of fracture is lower.

[0042] like Figure 8 As shown in the finite element simulation, the average pressure peak of the alloy tooth 10 (hexagon) optimized with an external convex surface appears on one side of the hexagon located in the center, indicating that the stress concentration effect is more significant here, which can cause rock breakage under low load.

[0043] The size and number of polygons constituting the convex surface of the alloy tooth 10 can be designed according to actual needs. By modifying the size and number of polygons constituting the convex surface of the alloy tooth 10, its load characteristics can be controlled. Specifically, when the size of the polygons constituting the convex surface of the alloy tooth 10 is smaller and the number is greater, the convex surface of the alloy tooth 10 is closer to a sphere, the contact process with the rock is smoother, the load fluctuation is reduced, which is beneficial to reducing the vibration of the hob, but at the same time it is not conducive to reducing the bending moment on the alloy tooth and reducing the risk of tooth breakage.

[0044] like Figure 6 As shown, the method for generating the polygonal surface of the alloy tooth 10 includes the following steps:

[0045] S1. Based on the polygon shape, polygon area, and radius of the alloy tooth 10, generate two adjacent polygon faces in 3D modeling software (such as SolidWorks). The two polygon faces share one edge, and their normals intersect at one point. The distance from the intersection point to the normals of the two polygon faces is equal and equal to the radius of the alloy tooth 10.

[0046] S2. Connect the intersection point with the vertices of the two polygonal faces to generate two cones;

[0047] S3. The base of the generated cone has at least two common edges with the adjacent polygon surface, and the vertices of the cone coincide with the vertices of the existing cones.

[0048] S4. Repeat step S3 until enough cones are generated so that the surface of the alloy tooth is completely covered by polygonal faces without adding new polygonal faces, and finally a sphere is formed. Divide the formed sphere into two hemispheres, which are the alloy tooth 10.

[0049] Example 2

[0050] like Figure 9 As shown, based on Embodiment 1, this utility model further includes a PLC controller and a sensor 11 disposed inside a blind hole within the alloy tooth 10. The PLC controller is connected to the sensor 11 via a wire and to a host computer via a wireless data transmission terminal. The PLC controller is model DVP32ES200R, and the wireless data transmission terminal is model 4G DTU-ZSD3400.

[0051] The sensor 11 is a resistive sensor that can monitor in real time whether the alloy tooth 10 has broken, so that construction personnel can replace the tool in time or formulate a reasonable tool replacement and maintenance plan. When the alloy tooth 10 breaks, its internal resistance is broken along with the alloy tooth 10, or exposed to the outside and damaged during contact with rocks or other objects, thus changing the resistance value. This changes the resistance value and serves as a signal indicating whether the alloy tooth 10 has broken. This signal is transmitted by a wireless data transmission terminal to the host computer in the tunnel boring machine's cab and displayed to the operator in real time.

Claims

1. A toothed hob with optimized alloy tooth surface structure, characterized in that, It includes a bearing (2) and a cutter shaft (3). The outer periphery of the bearing (2) is fitted with a cutter body (4), and the outer periphery of the cutter body (4) is fitted with a cutter ring (1). Alloy teeth (10) are evenly arranged on the outer periphery of the cutter ring (1). The blade body (4) is provided with end caps on both sides, and the end caps and bearings (2) are both sleeved on the blade shaft (3); It also includes a PLC controller and a sensor (11) set in a blind hole inside the alloy tooth (10). The sensor (11) is a resistive sensor. The PLC controller is connected to the sensor (11) by a wire and to the host computer by a wireless data transmission terminal.

2. The toothed hob with optimized alloy tooth surface structure according to claim 1, characterized in that, The blade body (4) is provided with a blade ring positioning ring (9) at the connection between the blade body (4) and the blade ring (1).

3. The toothed hob with optimized alloy tooth surface structure according to claim 1, characterized in that, The surface of the alloy tooth (10) is composed of multiple polygonal faces, including at least one of triangles, quadrilaterals, pentagons and hexagons.

4. The toothed hob with optimized alloy tooth surface structure according to claim 1, characterized in that, The alloy teeth (10) and the cutter ring (1) are embedded in the outer circumferential surface of the cutter ring (1) by an interference fit.

5. The toothed hob with optimized alloy tooth surface structure according to claim 4, characterized in that, The alloy teeth (10) are made of cemented carbide.

6. The toothed hob with optimized alloy tooth surface structure according to claim 1, characterized in that, The end caps include a left end cap (6) and a right end cap (5), which are respectively disposed on the left and right end faces of the blade body (4).

7. The toothed hob with optimized alloy tooth surface structure according to claim 6, characterized in that, The end cover is provided with a bearing seal ring (7) at the connection between the bearing (2) and the end cover is provided with a cutter shaft seal ring (8) at the connection between the end cover and the cutter shaft (3).

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