A center bit and a cutting head device

Abstract

The utility model relates to a kind of center cutter and tunneling cutter head device, center cutter is used to tunneling cutter head device.The center cutter includes pedestal, at least one second cutter body and multiple first cutter bodies fixed in the pedestal, the protruding height of the second cutter body is greater than the protruding height of first cutter body, the second cutter body is eccentric relative to the rotary center line of the center cutter.Set with second cutter body and first cutter body, and, second cutter body is eccentric relative to the center cutter, so that in the process of tunneling main machine propulsion, second cutter body will first tunneling tunnel segment The curved surface is formed positioning, then first cutter body carries out adjacent area broken tunneling, and tunneling stability is high.

Description

TECHNICAL FIELD

[0001] The utility model relates to a tunnel construction technical field especially relates to a center cutter and a tunneling cutter head device. BACKGROUND

[0002] After the main tunnel is spaced apart by a corresponding interval distance, a liaison passage is constructed by excavation, and if the center line of the liaison passage deviates from the horizontal plane in which the center line of the main tunnel is located (including deviation upward or downward), adverse effects of center deviation will occur in the process of breaking open the main tunnel segment by the tunneling equipment. Specifically, when the tunneling cutter head device rotates to excavate the main tunnel segment, the stress conditions on both sides of the center cutter will be different, and the center part of the center cutter protrudes, combined with the change in the curvature of the main tunnel segment, the unbalanced stress state of the center cutter can easily lead to floating or slipping of the tunneling main machine from the designed standard portal excavation position during the excavation process. In particular, when the tunneling cutter head device breaks open the outwardly convex tunnel segment, the existing sharp-pointed tunneling cutter head device cannot guarantee that the actual excavation center coincides with the design required tunnel center line.

[0003] Moreover, the unbalanced stress of the tunneling cutter head not only affects the stability of the tunneling main machine, but also can threaten the stability of the entire tunneling system. Although the disclosure document with publication number CN115584988A provides a cutter head for tunneling equipment and the tunneling equipment having the same, and the disclosure document with publication number CN208918540U provides an arc-shaped cutting shield tunneling machine cutter head, but in the tunnel construction in which the center line of the liaison passage deviates, the technical problems of inaccurate positioning of the excavation center and easy slipping of the tunneling cutter head from the deviation of the center line of the liaison passage from the center line of the main tunnel still need to be solved. SUMMARY

[0004] To overcome the problems in the related art, the embodiments of the utility model provide a tunneling cutter head device to solve the technical problems of inaccurate positioning of the excavation center of the cutter head device and easy slipping of the tunneling cutter head.

[0005] According to a first aspect of the embodiments of the utility model, a center cutter is provided for a tunneling cutter head device, the center cutter includes a base, a plurality of first cutter bodies fixed to the base at intervals, and at least one second cutter body, the second cutter body is eccentrically arranged relative to the rotation center line of the center cutter.

[0006] In the direction of the rotation center line of the center cutter, the end height of the second cutter body is greater than the end height of the first cutter body.

[0007] In an embodiment, the second cutter body is provided with two, and at least one first cutter body is arranged in the rotation area range of the two second cutter bodies.

[0008] In an embodiment, at least one third cutter body is arranged outside the rotation area range of the second cutter body, and the rotation radius of the second cutter body is smaller than the rotation radius of the third cutter body.

[0009] In an embodiment, within the rotation area range of the two second cutter bodies, the first cutter bodies are arranged in a stepped shape or a fitting arc shape.

[0010] The protrusion heights of the first cutter bodies are the same.

[0011] The protrusion heights of the first cutter bodies gradually increase or decrease from the center to both sides.

[0012] In an embodiment, in the direction of the rotation center line of the center cutter, the minimum height difference D between the first cutter body and the second cutter body is 5mm≤D≤80mm.

[0013] In an embodiment, the connecting line of the second cutter body and the first cutter bodies is a straight line.

[0014] The connecting line of the second cutter body and the first cutter bodies is a spiral line.

[0015] The connecting line of the second cutter body and the first cutter bodies is a radial line.

[0016] In an embodiment, the second cutter body and the first cutter body are respectively welded and fixed with the base.

[0017] The second cutter body and the first cutter body are respectively locked and connected with the base by using fasteners.

[0018] In an embodiment, the center cutter comprises at least one reinforcing beam fixed to the base, and the first cutter body and the second cutter body are fixedly arranged on the reinforcing beam.

[0019] In an embodiment, the second cutter body comprises a cutter body, a connecting end at one end of the cutter body, and a tunneling end at the other end of the cutter body, the connecting end is clamped and connected with the reinforcing beam and is welded and fixed, the second cutter body and the first cutter body are the same in structure, and a hard alloy cutter head is welded at the end of the first cutter body and the second cutter body.

[0020] In an embodiment, the base is arranged in a rectangular structure, a disc structure or a polygonal structure.

[0021] According to the second aspect of the embodiment of the utility model, the tunneling cutter head device comprises a cutter head assembly and the center cutter, the center cutter is fixedly connected with the cutter head assembly, and the cutter head assembly is provided with a hob mechanism, a tearing cutter mechanism, a gauge cutter mechanism and a scraper mechanism.

[0022] The technical scheme provided by the embodiment of the utility model can have the following beneficial effects: the center cutter is provided with a second cutter body and a first cutter body, the second cutter body is arranged eccentrically relative to the center cutter, so that in the advancing process of the tunneling host, the second cutter body can first excavate the curved surface of the tunnel segment to form positioning, and the center line of rotation of the tunneling host is arranged eccentrically relative to the excavating point of the second cutter body, so that the tunneling positioning of the tunneling host can be realized, and the risk of deviation of the tunneling direction can be reduced. Then, the first cutter body performs crushing excavation around the excavated area of the second cutter body, and the tunneling stability is high. The second cutter body and the first cutter body are distributed in different heights, and the excavation starts from the central area deviated from the center cutter, so that the risk of slippage deviation is reduced.

[0023] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0024] The drawings incorporated into the specification and constituting a part of the specification show embodiments consistent with the utility model, and together with the specification are used to explain the principles of the utility model.

[0025] Figure 1 is a three-dimensional schematic view of a center cutter according to an embodiment.

[0026] Figure 2 is a side view structural schematic view of a center cutter according to an embodiment.

[0027] Figure 3 is a front view structural schematic view of a radial center cutter according to an embodiment.

[0028] Figure 4 is a structural schematic view of a tunneling cutter head device according to an embodiment.

[0029] Figure 5 is a structural schematic view of a tunneling cutter head device excavating a tunnel segment according to an embodiment.

[0030] In the figure, base 10; second cutter body 20; excavating end 21; cutter main body 22; connecting end 23; first cutter body 30; reinforcing beam 40; cutter head assembly 50; hob mechanism 51; scraper mechanism 52; tunnel segment 60; third cutter body 70. DETAILED DESCRIPTION

[0031] Wherein, the drawings are only used for exemplary description, and the representation is only a schematic view, not a physical drawing, and cannot be understood as a limitation on the utility model; in order to better illustrate the embodiments of the utility model, some components of the drawings can be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it can be understood that some known structures and their descriptions in the drawings can be omitted.

[0032] In the description of the utility model, it is understood that the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, therefore, the terms describing the position relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation on the utility model, for ordinary skilled persons in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0033] In the description of the utility model, unless otherwise explicitly specified and limited, if the connecting relationship between the components appears, the term should be understood in a broad sense, for example, it can be fixedly connected, can be detachably connected, or be integrated; can be mechanically connected, can be electrically connected; can be directly connected, can be indirectly connected through an intermediate medium, can be the communication inside two components or the interaction relationship between two components. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0034] As shown in Figures 1 to 5 The utility model provides a center cutter for cutting and advancing cutter head device, the center cutter includes base 10, at least one second cutter body 20 and a plurality of first cutter body 30 fixedly spaced in base 10. The protruding height of second cutter body 20 is greater than the protruding height of first cutter body 30, and second cutter body 20 is arranged eccentrically relative to the rotation center line of the center cutter.

[0035] Second cutter body 20 and first cutter body 30 are block-shaped cutter structures, and the end protruding height of second cutter body 20 and first cutter body 30 is different, that is, in the direction of the rotation center line of the center cutter, the end height of second cutter body 20 is greater than the end height of first cutter body 30, thereby forming a rotating cutting trajectory with ups and downs. As preferably, the cross section of the cutting trajectory formed by second cutter body 20 and first cutter body 30 rotating with the cutting and advancing cutter head device is L-shaped, M-shaped, U-shaped or W-shaped. Preferably, the center cutter structure of second cutter body 20 and first cutter body 30 is M-shaped.

[0036] The second cutter body 20 is eccentrically arranged relative to the center cutter, so that during the advancing of the advancing main machine, the second cutter body 20 can first excavate the curved surface of the tunnel segment 60 to form positioning, and the center line of the rotation of the advancing main machine is eccentrically arranged relative to the excavating point of the second cutter body 20, so that the excavating positioning of the advancing main machine can be realized, and the risk of deviation of the excavating direction can be reduced. Then, the first cutter body 30 excavates the surrounding broken area of the excavated area of the second cutter body 20, and the excavating stability is high. The second cutter body 20 and the first cutter body 30 are distributed in a staggered manner, and the excavation starts from the center area of the center cutter, thereby reducing the risk of slipping deviation.

[0037] In a preferred embodiment, two second cutter bodies 20 are arranged, and the two second cutter bodies 20 are arranged at intervals to excavate the tunnel segment 60 from different angles. The second cutter body 20 has a large height, and the second cutter body 20 is distributed on both sides of the center line of the rotation of the center cutter, so that the tunnel segment 60 can be excavated according to the contact sequence of the tunnel segment. Preferably, the rotation tracks of the two second cutter bodies 20 coincide or partially coincide, and the second cutter bodies 20 excavate and position the tunnel segment 60 in turn.

[0038] At least one first cutter body 30 is arranged in the rotation area of the two second cutter bodies 20, and the first cutter body 30 is distributed between the two second cutter bodies 20, so that the center cutter forms a cutter arrangement structure with high on both sides and low in the middle. The rotation radius of the first cutter body 30 is smaller than the rotation radius of the second cutter body 20, the center line of the rotation of the center cutter is eccentrically arranged relative to the center of the main tunnel, and then during the rotation of the excavating cutter head device, the two second cutter bodies 20 can excavate the curved surface of the main tunnel segment 60 to form positioning in turn, and then the first cutter body 30 gradually participates in the excavation, so that the excavating center of the center cutter is not easy to deviate, and the excavating accuracy of the excavating cutter head device is improved. The center distance between the two second cutter bodies 20 and the center line of the rotation of the center cutter is adjustable, so as to adapt to the excavating cutter head device with different excavating requirements. In this embodiment, the two second cutter bodies 20 and the plurality of first cutter bodies 30 form a cutter arrangement structure with high on both sides and low in the middle.

[0039] Further, at least one third cutter body 50 is arranged outside the rotation range of the two second cutter bodies 20, and the rotation radius of the second cutter body 20 is smaller than that of the third cutter body 70. The third cutter body 70 expands the positioning range of the center cutter to accurately position the center of the tunneling cutter device, avoiding the sliding or deviation of the tunneling cutter device on the curved tunnel segment 60. In the embodiment, the two second cutter bodies 20 are columnar protrusions of the base 10, and the two second cutter bodies 20 are symmetrically or spacedly distributed relative to the center line of the base 10. The center cutter is provided with the second cutter body 20, the first cutter body 30 and the third cutter body 70, so that the center cutter can eccentrically tunnel the tunnel segment, and the tunneling effect is good. During the rotation of the tunneling cutter device, the second cutter body 20 arranged eccentrically tunnels the arc-shaped tunnel segment 60, and then the first cutter body 30 and the third cutter body 70 tunnel the tunnel segment 60, which can excavate the eccentrically arranged main tunnel and improve the accuracy of tunneling. Especially for the excavation of the outer anti-arc segment, the positioning effect of the segment grabbing and excavation is improved.

[0040] The second cutter body 20, the third cutter body 70 and the plurality of first cutter bodies 30 are fixed to the base 10, wherein the distribution of the second cutter body 20, the third cutter body 70 and the plurality of first cutter bodies 30 can be linear distribution or discrete distribution. The plurality of second cutter bodies 20 can be on the same rotation track, and the plurality of first cutter bodies 30 form a plurality of concentric rotation tracks. In an embodiment, the connecting line of the second cutter body 20, the third cutter body 70 and the plurality of first cutter bodies 30 is a straight line, that is, the plurality of second cutter bodies 20, the third cutter body 70 and the plurality of first cutter bodies 30 are distributed on the same radial line to form tunneling paths with different rotation radii. During the rotation of the tunneling cutter device, the rotation tracks of the first cutter body 30, the third cutter body 70 and the second cutter body 20 form a ring structure. Preferably, the straight line formed by the plurality of first cutter bodies 30, the third cutter body 70 and the two second cutter bodies 20 intersects with the center point of the center cutter.

[0041] In an embodiment, the connecting line of the second cutter body 20, the third cutter body 70 and the plurality of first cutter bodies 30 is a spiral line; the plurality of second cutter bodies 20, the third cutter body 70 and the plurality of first cutter bodies 30 are at different positions to form a spiral tunneling structure, so that the center cutter is uniformly stressed during the rotation of the tunneling cutter device.

[0042] In another embodiment, the connecting line of the second cutter body 20, the third cutter body 70 and the plurality of first cutter bodies 30 is a radial line, and the plurality of second cutter bodies 20, the third cutter body 70 and the plurality of first cutter bodies 30 are radially distributed to form a plurality of tunneling tracks, and the overall tunneling intensity is high. For example, the center cutter radially radiates three installation lines from the center to the periphery, and the second cutter body 20 and / or the first cutter body 30 can be installed on each installation line to improve the tunneling efficiency and positioning accuracy.

[0043] The end height of the second cutter body 20 is higher than the end height of the first cutter body 30. Correspondingly, the curve connecting the end of the second cutter body 20 and the end of the first cutter body 30 forms a stepped shape or a fitting arc-shaped concave, so that the arc-shaped tunnel segment can be excavated eccentrically. Among them, the second cutter body 20 can excavate the tunnel segment 60 first, guide other first cutter bodies 30 to excavate the tunnel segment 60, and the excavating cutter head device is not easy to move eccentrically.

[0044] In an embodiment, the protruding heights of the plurality of first cutter bodies 30 within the rotation range of the two second cutter bodies 20 are the same, that is, after the second cutter body 20 realizes excavation positioning, the first cutter bodies 30 are arranged in parallel to realize parallel excavation, and as the tunnel segment 60 is gradually excavated, the first cutter bodies 30 and the third cutter bodies 70 crush and advance the tunnel segment 60.

[0045] In an embodiment, the protruding heights of the plurality of first cutter bodies 30 within the rotation range of the two second cutter bodies 20 gradually increase from the center to both sides. That is, the protruding height of the middle first cutter body 30 is greater than the protruding height of the first cutter body 30 on both sides, and the protruding height of the middle first cutter body 30 is less than the protruding height of the second cutter body 20, thereby forming a double-arc excavation structure.

[0046] In another embodiment, the protruding heights of the plurality of first cutter bodies 30 within the rotation range of the two second cutter bodies 20 gradually decrease from the center to both sides, that is, the protruding height of the middle first cutter body 30 is less than the protruding height of the first cutter body 30 on both sides, and the second cutter body 20 and the first cutter body 30 form a concave arc excavation structure.

[0047] In the above embodiments, the third cutter body 70 is smaller than the second cutter body 20, and the height of the third cutter body 70 is less than or equal to or greater than the height of the first cutter body 30, so as to adapt to tunnel segments 60 with different curvatures.

[0048] In the direction of the rotation center line of the center cutter, the minimum height difference D between the first cutter body 30 and the second cutter body 20 is 5mm≤D≤80mm. The height difference between the first cutter body 30 and the second cutter body 20 can be set to 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm.

[0049] In a specific embodiment, five first cutter bodies 30 are arranged between the two second cutter bodies 20, and at least two third cutter bodies 70 are also distributed on the outer side of the two second cutter bodies 20. The height of the first cutter body 30 gradually decreases from the second cutter body 20 to both sides, and the connecting line of the top points of the five first cutter bodies 30 between the two second cutter bodies 20 is arc-shaped and concave downward. The five first cutter bodies 30 are spaced apart between the two second cutter bodies 20 to excavate the tunnel segment 60 in intervals.

[0050] The second cutter body 20, the third cutter body 70 and the first cutter body 30 are basically the same in structure, only different in height. The second cutter body 20 and the first cutter body 30 are fixedly connected with the base 10, and the fixing modes are basically the same. Taking the second cutter body 20 as an example, the end of the second cutter body 20 is provided with a cemented carbide cutter head.

[0051] In an embodiment, the second cutter body 20 and the first cutter body 30 are respectively connected with the base 10 by welding. The second cutter body 20 and the first cutter body 30 adopt an annular welding seam to connect and weld the second cutter body 20 and the base 10, so that the two are fixedly integrated. A plurality of second cutter bodies 20 and first cutter bodies 30 are respectively fixedly spaced to the base 10, and the welding is flexible.

[0052] In another embodiment, the second cutter body 20 and the first cutter body 30 are respectively connected with the base 10 by fastener locking. The second cutter body 20 and the first cutter body 30 are detachably connected with the base 10, so as to facilitate replacement of the second cutter body 20 and improve the convenience of replacement. Alternatively, the second cutter body 20 is embeddedly installed in the base 10, and a bolt locks and connects the second cutter body 20 and the base 10. Alternatively, the second cutter body 20 is provided with a flange seat, and a fastener passes through the flange seat to lock and connect the base 10, so as to be locked and connected.

[0053] In an embodiment, the center cutter includes at least one reinforcing beam 40 fixedly arranged on the base 10, and the first cutter body 30 and the second cutter body 20 are fixedly spaced on the reinforcing beam 40. The base 10 is a rigid structural member, and the reinforcing beam 40 is a protruding structure of the base 10. The reinforcing beam 40 can not only enhance the structural strength of the base 10, but also guide the spacing arrangement of the first cutter body 30 and the second cutter body 20. The first cutter body 30 and the second cutter body 20 are fixedly arranged on the reinforcing beam 40, so as to facilitate welding fixation. Preferably, the reinforcing beam 40 is arranged as a rectangular protruding rib, a trapezoidal protruding rib or a “T” shaped protruding rib. The first cutter body 30 and the second cutter body 20 are fixedly connected with the reinforcing beam 40, and the connection is convenient.

[0054] In an optional embodiment, the second cutter body 20 includes a cutter body 22, a connecting end 23 located at one end of the cutter body 22 and a tunneling end 21 located at the other end of the cutter body 22, the connecting end 23 is clamped and connected with the reinforcing beam 40 and is fixedly welded. The connecting end 23 is clamped and fixed on the reinforcing beam 40 to form a connecting and positioning structure. The connecting end 23 is fixedly welded with the reinforcing beam 40, and the welding positioning effect is good. The tunneling end 21 is arranged as a tapered or sharp, V-shaped structure or is provided with chamfers on both sides to reduce the cross section of the tunneling end 21. The tunneling end 21 laterally tunnels the tunnel segment 60 and the soil layer with rotation, which can not only reduce the tunneling resistance, but also improve the wear resistance.

[0055] As a preferred, the tunneling end 21 is welded with a cemented carbide cutter head, so as to improve the tunneling efficiency and service life of tunneling and excavation.

[0056] In another alternative embodiment, the second cutter body 20 includes a cutter body 22, a tunneling column is welded and fixed on the reinforcing beam 40, and the cutter body 22 is welded to the end of the tunneling column to form an replaceable welded structure.

[0057] like Figures 3 to 5 As shown, a central cutter is applied to a tunneling cutterhead device, which includes a cutterhead assembly 50 and a central cutter. The central cutter is embedded and fixedly connected to the cutterhead assembly 50. The cutterhead assembly 50 is equipped with a rolling cutter mechanism 51, a tearing cutter mechanism, a gauge-maintaining cutter mechanism, and a scraper mechanism 52. The central cutter is embedded and installed at the center of the cutterhead assembly 50. The central cutter positions the initial position of the tunnel segment 60 being excavated, forming the center positioning for the tunnel segment 60 excavation. The cutterhead assembly 50 then expands the tunnel segment 60 for further excavation.

[0058] In one embodiment, the base 10 and the cutter head assembly 50 are assembled and connected. Optionally, the base 10 is embedded in the cutter head assembly 50 to facilitate the assembly and connection. The base 10 is configured as a rectangular structure, a disc-shaped structure, or a polygonal structure. Correspondingly, the cutter head assembly 50 is provided with a mounting hole located at the center of the cutter head assembly 50, so that the base 10 can be embedded in the mounting hole for convenient assembly and connection.

[0059] In one embodiment, the cutterhead assembly 50 includes a cutterhead holder, a rolling cutter mechanism 51 mounted on the cutterhead holder, and a scraper mechanism 52. The cutterhead holder has an arc-shaped surface, and the rolling cutter mechanism 51 and the scraper mechanism 52 are spaced apart on the cutterhead holder and extend beyond the arc-shaped surface, thereby enabling progressive tunneling during the tunneling process of the cutterhead device and improving the flexibility of tunneling. Preferably, the rolling cutter mechanism 51 is radially spaced along the cutterhead holder; specifically, the rolling cutter mechanism 51 has an intersecting cross-shaped structure or a star-shaped structure.

[0060] The scraper mechanism 52 is equipped with a crusher, shell cutter or other tunneling cutter structure, and the scraper mechanism 52 is distributed in the space between the scraper mechanisms 52.

[0061] In one embodiment, the base 10 is embedded in the cutter head assembly 50, and the base 10 and the cutter head assembly 50 are fixedly connected. The base 10 and the cutter head assembly 50 are fitted together to form a positioning structure. Preferably, the joint between the base 10 and the cutter head assembly 50 is welded and fixedly connected, resulting in accurate installation and good joint effect.

[0062] In one embodiment, the rotation centerline of the central cutter is eccentrically positioned to the center of the tunnel being excavated by the cutterhead device. During the rotation of the cutterhead device, the rotation centerline of the central cutter breaks through and excavates along the main tunnel segment 60. The rotation centerline of the central cutter is located below the horizontal axis of the main tunnel, thus constituting asymmetrical excavation on both sides of the central cutter.

[0063] Preferably, the eccentricity of the center line of rotation of the center knife and the horizontal plane in which the main tunnel axis lies is 100-500 mm.

[0064] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0065] It is to be understood that the application is not limited to the precise structures hereinabove described and shown in the drawings, for purposes of illustration and description, and that various modifications can be made therein without departing from the scope of the application. The scope of the application is indicated only by the appended claims.

Claims

1. A center bit for a drag bit assembly, comprising: The center cutter comprises a base, a plurality of first cutter bodies and at least one second cutter body fixedly arranged on the base, and the second cutter body is arranged eccentrically relative to the center line of the center cutter; The end height of the second cutter body is greater than that of the first cutter body in the direction of the center line of the center cutter.

2. The center knife of claim 1, wherein, The second cutter body is provided with two, and the range of the rotation area of the two second cutter bodies has at least one first cutter body.

3. The centre-knife according to claim 1 or 2, characterized in that At least one third cutter body is arranged outside the rotation area of the second cutter body, and the rotation radius of the second cutter body is smaller than that of the third cutter body.

4. The center knife of claim 2, wherein, In the rotation area of the two second cutter bodies, the plurality of first cutter bodies are arranged in a stepped or fitted arc shape. The protrusion heights of the plurality of first cutter bodies are the same; or The protrusion heights of the plurality of first cutter bodies gradually increase or decrease from the center to both sides.

5. The center knife of claim 1 wherein, In the direction of the center line of the center cutter, the minimum height difference D between the first cutter body and the second cutter body satisfies 5mm≤D≤80mm.

6. The center knife of claim 1 wherein, The connecting line of the second cutter body and the plurality of first cutter bodies is a straight line; or The connecting line of the second cutter body and the plurality of first cutter bodies is a spiral line; or The connecting line of the second cutter body and the plurality of first cutter bodies is a radial line.

7. The center knife of claim 1 wherein, The second cutter body and the first cutter body are respectively welded and fixed with the base; or The second cutter body and the first cutter body are respectively locked and connected with the base by using fasteners.

8. The center knife of claim 1 wherein, The center cutter comprises at least one reinforcing beam fixedly arranged on the base, and the first cutter body and the second cutter body are fixedly arranged on the reinforcing beam.

9. The center knife of claim 8, wherein, The second cutter body comprises a cutter body, a connecting end at one end of the cutter body, and a tunneling end at the other end of the cutter body, the connecting end is engaged and connected with the reinforcing beam and is welded and fixed, the second cutter body and the first cutter body are the same in structure, and a hard alloy cutter head is welded at the end of the first cutter body and the second cutter body.

10. The center knife of claim 1 wherein, The base is arranged in a rectangular structure, a disc structure or a polygonal structure.

11. A cutting head arrangement, characterized by The tunneling cutter head device comprises a cutter head assembly and the center cutter according to any one of claims 1 to 10, the center cutter is fixedly connected with the cutter head assembly, and the cutter head assembly is provided with a hob mechanism, a tearing cutter mechanism, a gauge cutter mechanism and a scraper mechanism.

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