Inserted hob for optimizing alloy tooth surface structure

Abstract

The invention discloses an inserted tooth hob with an optimized alloy tooth surface structure, and relates to the technical field of inserted tooth hobs, the inserted tooth hob comprises a bearing and a cutter shaft, the periphery of the bearing is sleeved with a cutter body, the periphery of the cutter body is sleeved with a cutter ring, and the periphery of the cutter ring is uniformly provided with alloy teeth with optimized surfaces; 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 polygon sizes and numbers, so that the inserted tooth hob using the alloy teeth has the capacity 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] The invention relates to the technical field of insert hobs, in particular to an insert hob with an optimized alloy tooth surface structure. Background Art

[0002] Full-section tunnel boring machines are large-scale mechanical equipment used for underground space development. They have fast excavation speed, no need for blasting operations, and little disturbance to surface buildings. They are currently the preferred solution for the construction of difficult underground facilities such as urban subway tunnels, cross-river and sea-jumping tunnels, and water diversion tunnels for pumped storage power stations. The continuous development of efficient, safe, and economical full-section tunnel boring machines is an objective demand formed in the process of national infrastructure construction.

[0003] The roller cutter is a key component for rock breaking and excavation. The roller cutter is located at the front end of the full-section tunnel boring machine, installed on the cutterhead (a total of about 30 to 60 roller cutters are installed), and is in direct contact with the rock mass. When the full-section tunnel boring machine is working, the hydraulic system pushes the cutterhead forward, and the motor drives the cutterhead to rotate around its own axis. At this time, the roller cutter is driven by the cutterhead to penetrate the rock, causing the surface rock to break and fall off on the path it passes, so that the full-section tunnel boring machine can gradually move forward. It can be seen that the difficulty of the roller cutter penetrating the rock and its service life are the key factors that determine the construction speed of the full-section tunnel boring machine.

[0004] Inserted tooth cutter is a type of full-face tunnel boring machine cutter. Specifically, holes are opened at fixed intervals on the outer circumference of the cutter, and alloy teeth are embedded in the holes. The top of the alloy teeth is higher than the outer circumference of the cutter. When breaking rocks, the alloy teeth replace the cutter surface to contact the rock. Generally speaking, the protruding part of the alloy teeth is spherical or wedge-shaped, with a small contact area with the rock and a strong stress concentration effect. It can penetrate the rock under a relatively low thrust. At the same time, the alloy teeth have high hardness and stronger wear resistance. In theory, the inserted tooth cutter can achieve high rock breaking efficiency and long service life at the same time.

[0005] However, in actual engineering, the main failure mode of the insert cutter is the breakage of the alloy teeth (i.e. the protruding part of the alloy teeth breaks along the boundary between the alloy teeth and the outer peripheral surface of the cutter). From the working principle of the insert cutter mentioned above, it can be seen that after the alloy teeth break, the insert cutter immediately loses part or all of its ability to crush rocks. If it is not discovered and replaced in time, there is a risk of further damage to the surrounding tools and cutterheads.

[0006] The main reason for the fracture of the alloy teeth of the toothed hob is the unreasonable distribution of the load acting on it. During the rock crushing process, the contact force on the alloy teeth first increases and then gradually decreases as the hob rolls forward, and when the contact force reaches the maximum value, the direction of the contact force does not coincide with the axis of the alloy tooth, which forms a bending moment on the alloy tooth and causes the alloy tooth to break.

[0007] The problem of alloy teeth being easy to break results in a short actual life of the insert cutter and a high degree of uncertainty. When using the insert cutter, it is inevitable to frequently inspect and replace it, which makes it impossible to give full play to the advantages of the insert cutter, such as low load and strong wear resistance. When faced with extremely hard rock and high ground stress, where ordinary cutters are difficult to dig, the lack of safe and reliable insert cutters restricts the construction speed of full-face tunnel boring machines, wastes a lot of manpower and material resources, and significantly increases engineering costs. Therefore, the development of an insert cutter that is resistant to fracture failure has important engineering application significance.

[0008] In recent years, there have been some patents on insert hobs, but they have not yet been designed from the perspective of improving the fracture resistance of alloy teeth. For example, the Chinese utility model patent entitled "A high temperature and wear resistant insert hob" with application number CN202323369982.5 improves the wear resistance of insert hobs through surface coating; the Chinese invention patent entitled "A method for evaluating the service life of insert hob ring" with application number CN202310879465.8 determines the remaining service life of insert hobs through indicators such as the amount of alloy tooth wear and whether the alloy teeth are loose. Summary of the invention

[0009] The purpose of the present invention is to provide an insert cutter with an optimized alloy tooth surface structure, which improves the fracture resistance of the alloy teeth by optimizing the surface structure of the metal teeth, and solves the problem of easy fracture and failure of the alloy teeth of the existing insert cutter by regulating the stress state of the alloy teeth during the rock crushing process, thereby extending the service life of the insert cutter and reducing the use cost of a full-section tunnel boring machine.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] An insert hob with optimized alloy tooth surface structure comprises a bearing and a cutter shaft, wherein a cutter body is sleeved on the outer periphery of the bearing, a cutter ring is sleeved on the outer periphery of the cutter body, and alloy teeth with optimized surface are evenly arranged on the outer periphery of the cutter ring;

[0012] End covers are arranged on both sides of the knife body, and the end covers and bearings are sleeved on the knife shaft.

[0013] In some embodiments, a knife ring positioning ring is provided at the connection between the knife body and the knife ring to restrict the movement of the knife 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 crushing and avoid additional bending moment on the alloy tooth, which may cause it to break.

[0015] In some embodiments, according to actual needs, the method for generating a polygonal surface of an alloy tooth includes the following steps:

[0016] S1. According to the polygon shape, polygon area and alloy tooth radius to be used by the alloy tooth, two adjacent polygonal faces are generated in space. The two polygonal faces share one edge, and the normals intersect at one point. The normal distances from the intersection point to the two polygonal faces are equal and equal to the radius of the alloy tooth.

[0017] S2, connecting the intersection point and the vertices of the two polygonal faces to generate two cones;

[0018] S3: The base of the generated cone has at least two common edges with the adjacent polygonal surface, and the vertex of the cone coincides with the vertex of the existing cone;

[0019] S4, repeat step S3 until the generated cone forms a sphere, and divide the formed sphere into two hemispheres, wherein the hemispheres are the alloy teeth.

[0020] In some embodiments, the alloy teeth are embedded in the outer circumferential surface of the cutter ring through interference fit.

[0021] In some embodiments, the alloy teeth are made of cemented carbide.

[0022] In some embodiments, the end cover includes a left end cover and a right end cover, which are respectively arranged on the left and right end surfaces of the blade body.

[0023] In some embodiments, a bearing sealing ring is provided at the connection between the end cover and the bearing, and a knife shaft sealing ring is provided at the connection between the end cover and the knife shaft.

[0024] In some embodiments, a PLC controller and a sensor disposed inside the alloy tooth are also included, wherein the PLC controller is connected to the sensor via a wire and is connected to a host computer via a wireless data transmission terminal. Whether the alloy tooth is broken can be monitored in real time, so that construction personnel can replace the tool in time, or formulate a reasonable tool replacement and maintenance plan.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention replaces the spherical surface of the traditional alloy tooth with a surface composed of multiple polygons. At this time, the maximum contact force between the alloy tooth and the rock will appear on a certain edge of the polygon in the center of the alloy tooth. On the one hand, the sharp structure formed by the common edges of two adjacent polygons increases the stress concentration effect, making it easier for the insert cutter using the alloy tooth to crush rocks. On the other hand, the position of the maximum contact force on the alloy tooth is closer to the center of the alloy tooth, the angle between the direction of the maximum contact force and the direction of the axis of the alloy tooth is reduced, the maximum bending moment caused by the maximum contact force to the alloy tooth is reduced, and the risk of alloy tooth breakage is reduced.

[0027] The alloy teeth described in the present invention have an outward convex surface structure, and the size, direction, and fluctuation degree of the force on the alloy teeth can be adjusted by designing different polygonal sizes and quantities, so that the insert hob using the alloy teeth has the ability to adapt to different geological working conditions, thereby avoiding the problems of excessive load and excessive vibration caused by the hob's inability to adapt to the geological environment when working.

[0028] The sensor and PLC controller of the present invention can enable construction personnel to intuitively know the number of broken and failed alloy teeth of the insert hob, so as to replace the damaged insert hob in time and avoid continuous use of the insert hob with broken teeth, which may cause damage to adjacent tools or cutter disc structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0030] Figure 2 It is a schematic cross-sectional structure diagram of Embodiment 1 of the present invention;

[0031] Figure 3 It is a schematic diagram of the cross-sectional structure of the alloy tooth and the cutter ring of Example 1 of the present invention;

[0032] Figure 4 Schematic diagram of the structure of the alloy tooth of Example 1 of the present invention (pentagon);

[0033] Figure 5 It is a structural schematic diagram of the alloy tooth of Example 1 of the present invention (triangle);

[0034] Figure 6 This is a schematic diagram of generating the outer convex surface of the alloy tooth in Example 1 of the present invention;

[0035] Figure 7 It is a schematic diagram of load variation of the alloy teeth after surface structure optimization in the rock breaking process according to Example 1 of the present invention;

[0036] Figure 8 The average contact pressure distribution on the alloy tooth surface after the surface structure is optimized in Example 1 of the present invention;

[0037] Fig. 9 This is a schematic diagram of the structure of Example 2 of the present invention.

[0038] As shown in the figure:

[0039] 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 DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] See also Figure 1-Figure 5 A toothed hob with optimized alloy tooth surface structure comprises 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.

[0043] The alloy teeth 10 and the cutter ring 1 are embedded in the outer circumferential surface of the cutter ring 1 through 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 the groove of the outer circumference of the cutter body 4 to restrict the movement of the cutter ring 1.

[0044] End covers are provided on both sides of the cutter body 4, and the end covers and the bearing 2 are sleeved on the cutter shaft 3. The end covers include a left end cover 6 and a right end cover 5, which are respectively installed on the left and right end surfaces of the cutter body 4 by bolts. A bearing seal ring 7 is provided at the connection between the end cover and the bearing 2, and a cutter shaft seal ring 8 is provided at the connection between the end cover and the cutter shaft 3.

[0045] The alloy tooth 10 is made of cemented carbide. The alloy tooth 10 has an optimized convex surface structure, which is composed of a plurality of polygonal faces, and can change the direction of the load on the alloy tooth 10 during the rock crushing process, so as to avoid the alloy tooth 10 from being broken due to the additional bending moment. The polygonal faces include at least one of a triangle, a quadrilateral, a pentagon, and a hexagon. The convex surface of the alloy tooth 10 will not have an arc shape, but only a straight line shape (i.e., the edge of the polygon), so that the maximum contact force between the alloy tooth 10 and the rock appears on a certain edge 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 direction of the axis of the alloy tooth, reducing the maximum bending moment on the alloy tooth 10, reducing the possibility of the alloy tooth 10 breaking under the action of the bending moment, extending the service life of the insert cutter, reducing the frequency of replacing the insert cutter, and thus reducing the cost of tunnel excavation using a full-section tunnel boring machine.

[0046] like Figure 7As shown, in the finite element simulation, in the process of rolling through the rock surface, the maximum contact force of the alloy tooth 10 with optimized convex surface appears in the middle and rear part of the rolling distance. 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 angle between the two is small. The bending moment of the alloy tooth 10 is lower, and the risk of fracture is lower.

[0047] like Figure 8 As shown, in the finite element simulation, the average pressure peak of the alloy tooth 10 (hexagon) with optimized convex surface appears on one side of the hexagon located in the center, indicating that the stress concentration effect here is more significant, and the rock can be broken under a lower load.

[0048] The size and number of the polygons constituting the convex surface of the alloy tooth 10 can be designed according to actual needs. By modifying the size and number of the polygons constituting the convex surface of the alloy tooth 10, its load characteristics can be adjusted. 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 spherical surface, 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 of the alloy tooth and reducing the risk of tooth breakage.

[0049] like Figure 6 As shown, the method for generating the polygonal surface of the alloy tooth 10 includes the following steps:

[0050] S1. Generate two adjacent polygonal faces in a three-dimensional modeling software (such as solidworks) according to the polygonal shape, polygonal area and radius of the alloy tooth 10 to be used. The two polygonal faces share one edge, and the normals intersect at one point. The normal distances from the intersection point to the two polygonal faces are equal and equal to the radius of the alloy tooth 10.

[0051] S2, connecting the intersection point and the vertices of the two polygonal faces to generate two cones;

[0052] S3: The base of the generated cone has at least two common edges with the adjacent polygonal surface, and the vertex of the cone coincides with the vertex of the existing cone;

[0053] 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. The formed sphere is divided into two hemispheres, and the hemispheres are the alloy teeth 10.

[0054] Example 2

[0055] like Fig. 9As shown, based on Example 1, the present invention further includes a PLC controller and a sensor 11 disposed in a blind hole inside the alloy tooth 10. The PLC controller is connected to the sensor 11 via a wire, and is connected to the host computer via a wireless data transmission terminal. The model of the PLC controller is DVP32ES200R, and the model of the wireless data transmission terminal is 4GDTU-ZSD3400.

[0056] The sensor 11 is a resistive sensor, which can monitor whether the alloy tooth 10 is broken in real time online, so that the construction personnel can replace the tool in time, or formulate a reasonable tool replacement and maintenance plan. When the alloy tooth 10 is broken, the internal resistor is broken along with the alloy tooth 10, or exposed to the outside, and damaged in the process of contact with rocks or other objects, and then the resistance value changes, and serves as a signal indicating whether the alloy tooth 10 is broken. The signal is transmitted by the wireless data transmission terminal to the host computer in the cab of the tunnel boring machine and displayed to the driver in real time.

Claims

1. An insert hob with optimized alloy tooth surface structure, characterized in that: It comprises a bearing (2) and a knife shaft (3), wherein a knife body (4) is sleeved on the outer periphery of the bearing (2), a knife ring (1) is sleeved on the outer periphery of the knife body (4), and alloy teeth (10) are evenly arranged on the outer periphery of the knife ring (1); End covers are provided on both sides of the knife body (4), and the end covers and the bearings (2) are both sleeved on the knife shaft (3).

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

3. The insert hob with optimized alloy tooth surface structure according to claim 1, characterized in that: The surface of the alloy tooth (10) is composed of a plurality of polygonal faces, and the polygonal faces include at least one of a triangle, a quadrilateral, a pentagon, and a hexagon.

4. The insert hob with optimized alloy tooth surface structure according to claim 3, characterized in that: The method for generating a polygonal surface of an alloy tooth (10) comprises the following steps: S1. According to the polygonal shape, polygonal area and radius of the alloy tooth (10) to be used by the alloy tooth (10), two adjacent polygonal faces are generated in space, the two polygonal faces share one edge, and the normals intersect at one point, and the normal distances from the intersection point to the two polygonal faces are equal and equal to the radius of the alloy tooth (10); S2, connecting the intersection point and the vertices of the two polygonal faces to generate two cones; S3: The base of the generated cone has at least two common edges with the adjacent polygonal surface, and the vertex of the cone coincides with the vertex of the existing cone; S4, repeat step S3 until the generated cone forms a sphere, and divide the formed sphere into two hemispheres, wherein the hemispheres are the alloy teeth (10).

5. The insert hob with optimized alloy tooth surface structure according to claim 1, characterized in that: The alloy teeth (10) are embedded in the outer circumferential surface of the cutter ring (1) through interference fit with the cutter ring (1).

6. The insert hob with optimized alloy tooth surface structure according to claim 5, characterized in that: The alloy teeth (10) are made of hard alloy.

7. The insert hob with optimized alloy tooth surface structure according to claim 1, characterized in that: The end cover comprises a left end cover (6) and a right end cover (5), which are respectively arranged on the left and right end surfaces of the knife body (4).

8. The insert hob with optimized alloy tooth surface structure according to claim 7, characterized in that: A bearing sealing ring (7) is provided at the connection between the end cover and the bearing (2), and a knife shaft sealing ring (8) is provided at the connection between the end cover and the knife shaft (3).

9. The insert hob with optimized alloy tooth surface structure according to claim 1, characterized in that: It also includes a PLC controller and a sensor (11) arranged inside the alloy tooth (10); the PLC controller is connected to the sensor (11) via a wire, and is connected to a host computer via a wireless data transmission terminal.

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