Mining multi-stage adjusting drill bit

Abstract

The invention belongs to the field of mining mechanical equipment, relates to a coal mine drilling machine, and provides a mining multi-stage adjusting drill bit which comprises a drill bit body, cutter wings, a tooth holder and a PDC blade, the cutter wings comprise three fixed cutter wings, three sets of middle movable cutter wings and three tail section movable cutter wings, and each middle movable cutter wing comprises a middle arc plate matched with the drill bit body in a nested mode. The middle arc plate is provided with a middle blade matched with the tail end of the fixed blade, the tail section movable blade comprises a tail section arc plate matched with the drill bit body in an embedded mode, the tail section arc plate is provided with a tail section blade, and the middle movable blade and the tail section movable blade can form a three-blade, a six-blade and a nine-blade with the fixed blade through rotation adjustment. The middle arc plate and the tail section arc plate are each provided with a plurality of positioning pins connected with the drill bit body, and the positioning pins are used for positioning the middle movable blades and the tail section movable blades. The device is reasonable in design, high in drilling capacity, high in reliability, long in service life and suitable for large-scale popularization.

Description

Technical Field

[0001] The invention belongs to the field of mining machinery and equipment, relates to a coal mine drill, and in particular to a multi-stage adjustable drill bit for mining. Background Art

[0002] Mechanized coal mining can reduce physical labor, improve safety, and achieve the goals of high output, high efficiency, and low consumption. Drilling is required before coal mining, and the drill bits used for drilling are now mostly diamond drill bits. The drill bits are mostly one-piece drill bits, the entire drill bit has no moving parts, the structure is relatively simple, and it has the ability to resist impact. In addition, when drilling in soft-medium-hard formations, diamond drill bits have the advantages of fast speed, large footage, long life, stable operation, few underground accidents, and good wellbore quality. According to the number of blades of the diamond drill bit, it can be divided into three blades, four blades, five blades, six blades, seven blades, and eight blades. For example, the existing patent CN219528932U discloses a drill bit for coal mine drilling with an internal circulation cooling function. The drill bit has six fixed blades. In addition to the advantages of ordinary diamond drill bits, it can also circulate and cool down to increase its drilling life; for example, CN202021338623.7 discloses a PDC drill bit with three evenly distributed blades for mining. The drill bit has the characteristics of good wear resistance and strong drilling ability.

[0003] Since most diamond drill bits have fixed blades, the number of blades affects their drilling capabilities in the following ways: if there are fewer blades, the drill bit is easy to penetrate into the formation, and the mechanical drilling speed of composite drilling is high, but if it encounters soft coal seams, the pump will be blocked; if there are more blades, the drill bit is difficult to penetrate into the formation, and the mechanical drilling speed of composite drilling is low, but it is more stable in soft-medium-hard coal seams. Therefore, in actual drilling operations, drill bits with fixed number of blades are generally selected through evaluation, but the actual utilization rate of the drill bit will be reduced, especially as consumables, which will increase the cost of drilling operations.

[0004] The existing patent CN105443043A discloses a PDC drill bit with a variable number of blades, including a matrix, a hydraulic channel, a nozzle, a fixed blade, a movable blade, a retaining spring, a T-shaped block, a T-shaped slot, and a limit anti-drop block. The fixed blade is fixed to the matrix and connected to it as a whole; the movable blade is limited in the T-shaped slot on the matrix by the T-shaped block, and the lower part of the slot has a limit anti-drop block and the upper part has a retaining spring. Although the drill bit can obtain an adjustable number of blades, the connection reliability of the connection method used is low, especially in the process of drilling in coal and rock, and its actual service life is greatly affected. Summary of the invention

[0005] In view of the technical problems existing in the above-mentioned coal mine drilling drill bit, the present invention proposes a mine-use multi-stage adjustable drill bit with reasonable design, strong drilling ability, high reliability and long service life.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is that a multi-stage adjustable drill bit for mining provided by the present invention comprises a drill bit body, an internal circulation cooling channel is arranged inside the drill bit body, a blade is arranged outside the drill bit body, a plurality of tooth seats distributed along the length direction thereof are arranged on the blade, a PDC blade is arranged on the tooth seat, the blade comprises three fixed blades distributed in a circular array at the head of the drill bit body, the head end of the fixed blade is close to the center of the drill bit body and the tail end thereof extends to the side of the drill bit body, and three groups of intermediate movable blades and three The tail section movable blade wing, the middle movable blade wing includes a middle arc plate nested with the drill body, the middle arc plate is provided with a middle blade wing that cooperates with the tail end of the fixed blade wing, the tail section movable blade wing includes a tail section arc plate nested with the drill body, the tail section arc plate is provided with a tail section blade that cooperates with the middle blade wing, the middle movable blade wing and the tail section movable blade wing can form three blades, six blades and nine blades with the fixed blade wing through rotation adjustment, the middle arc plate and the tail section arc plate are both provided with a plurality of positioning pins connected to the drill body, and the positioning pins are used to position the middle movable blade wing and the tail section movable blade wing.

[0007] Preferably, a first step opening is provided at the bottom of the fixed blade, a first wedge opening is provided on the inner side of the first step opening, the first step opening and the first wedge opening are both blocking surfaces facing the working surface of the PDC blade, and a middle three-sided three-dimensional wing step is provided on the top of the middle movable blade that matches the first step opening and the first wedge opening face to face.

[0008] Preferably, a second step opening is provided at the bottom of the middle movable blade, a second wedge opening is provided on the inner side of the second step opening, the second step opening and the second wedge opening are both blocking surfaces facing the working surface of the PDC blade, and a three-dimensional tail section wing step is provided on the top of the tail movable blade that matches the second step opening and the second wedge opening face to face.

[0009] Preferably, the three-sided three-dimensional wing step in the middle includes a first wedge surface obliquely connected to the side of the drill bit body, a first horizontal surface is arranged at the bottom of the first wedge surface, a first inclined step surface is arranged on the side of the first wedge surface and the first horizontal surface, and a first supporting horizontal surface is arranged at the bottom of the first inclined step surface; the three-sided three-dimensional wing step in the tail section includes a second wedge surface obliquely connected to the side of the drill bit body, a second horizontal surface is arranged at the bottom of the second wedge surface, a second inclined step surface is arranged on the side of the second wedge surface and the second horizontal surface, and a second supporting horizontal surface is arranged at the bottom of the second inclined step surface; the three-sided three-dimensional wing step in the middle and the three-sided three-dimensional wing step in the tail section are both provided with carbide bodies on the edges facing the rotational working direction of the PDC blade.

[0010] Preferably, the side of the drill body is provided with an embedding groove corresponding to the middle arc plate and the tail arc plate, the embedding groove includes an outer ring segment, and the side of the outer ring segment facing the center of the drill bit is provided with a plurality of axially spaced inner ring segments, the combined cross-section of the inner ring segment and the outer ring segment is T-shaped, and a circular ring segment is provided on the inner ring segment, the cross-sectional diameter of the circular ring segment is larger than the axial depth of the inner ring segment, the outer side of the middle arc plate and the outer side of the tail arc plate are both located on the same conical surface as the side of the drill body, and the inner side of the middle arc plate and the inner side of the tail arc plate are both provided with a plurality of convex plates corresponding to the inner ring segments one by one, and the convex plates are provided with annular protrusions cooperating with the circular ring segments.

[0011] Preferably, the drill body is provided with pin holes for connecting positioning pins, and the number of the pin holes is a multiple of the number of positioning pins on the same horizontal surface.

[0012] Preferably, the positioning pin is a tapered pin and is tightly fitted with the pin hole.

[0013] Preferably, the head of the drill body is provided with a wear-resistant surfacing layer distributed between adjacent fixed blades, and the tail end of the wear-resistant surfacing layer extends to the side of the drill body.

[0014] Preferably, the three blades formed by sequentially connecting the fixed blade, the middle movable blade and the tail movable blade have a spiral structure.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are:

[0016] 1. The present invention provides a multi-stage adjustable drill bit for mining, wherein the three blades are all designed in sections, and the fixed blade, the middle movable blade and the tail movable blade are connected to form a three-blade structure, the middle movable blade and the tail movable blade are connected in sequence and staggered with the fixed blade, and the drill is in a six-blade structure. The fixed blade, the middle movable blade and the tail movable blade are all staggered to form a nine-blade structure. In this way, the drill can be adjusted to different blade states according to actual conditions, so that the drill can maintain a good drilling efficiency during the composite drilling process, and the structural reliability is high, the working stability is good, and it is conducive to improving the comprehensive utilization rate of the blade. The device has a reasonable design, strong drilling ability, high reliability and long service life, and is suitable for large-scale promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 An axonometric diagram of a multi-stage adjustable drill bit for mining in a three-blade state provided in an embodiment;

[0019] Figure 2 A front view of a multi-stage adjustable drill bit for mining in a three-blade state provided in an embodiment;

[0020] Figure 3 A schematic diagram of the distribution of the embedded grooves on the drill body provided in the embodiment;

[0021] Figure 4 A top view of a multi-stage adjustable drill bit for mining in a three-blade state provided in an embodiment;

[0022] Figure 5 An axonometric diagram of a multi-stage adjustable drill bit for mining in a nine-blade state provided in an embodiment;

[0023] Figure 6 A front view of a multi-stage adjustable drill bit for mining provided in an embodiment in a nine-blade state;

[0024] Figure 7 An axonometric view of the intermediate movable blade provided in the embodiment;

[0025] In the above figures, 1, drill body; 2, blade; 21, fixed blade; 211, first step; 212, first wedge; 22, middle movable blade; 221, middle arc plate; 222, middle blade; 223, middle three-sided three-dimensional wing; 223a, first wedge surface; 223b, first horizontal platform surface; 223c, first inclined step surface; 223d, first support horizontal platform surface; 224, second step; 225, second wedge; 23, tail movable blade Wing; 231, tail section arc plate; 232, tail section blade; 233, three-sided three-dimensional wing step of the tail section; 233a, second wedge surface; 233b, second horizontal platform surface; 233c, second inclined step surface; 233d, second support horizontal platform surface; 24, convex plate; 25, annular protrusion; 26, cemented carbide body; 3, tooth seat; 4, PDC blade; 5, positioning pin; 6, embedded groove; 61, outer ring segment; 62, inner ring segment; 63, circular ring segment; 7, pin hole; 8, wear-resistant surfacing layer. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear below, they only indicate that the upper, lower, left and right directions are consistent with the accompanying drawings themselves, and do not limit the structure.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0028] Examples, such as Figure 1 As shown in FIG. 7 , a multi-stage adjustable drill bit for mining provided by the present invention comprises a drill bit body 1, wherein the drill bit body 1 is provided with an internal circulation cooling channel (not shown in the figure), and the drill bit body 1 is provided with a blade wing 2 on the outside, and the blade wing 2 is provided with a plurality of tooth seats 3 distributed along its length direction, and the tooth seat 3 is provided with a PDC blade 4. Among them, the internal circulation cooling channel is used to pass a cooling medium to cool the drill bit, and the plurality of PDC blades 4 on the blade wing 2 are fixed on the working path of the drill bit body 1 through the tooth seat 3, which can ensure that the drill bit has a strong rotary cutting ability and wear resistance on coal and rock. The internal circulation cooling channel, the tooth seat 3 and the PDC blade 4 are existing mature technologies, and this embodiment will not be repeated here. Different from the design of the existing fixed-wing drill bit, the present invention provides a blade wing 2 with adjustable angle, and correspondingly makes reasonable improvements to the drill bit body 1 to ensure the working performance of the drill bit.

[0029] In order to improve the working performance of the drill bit, the blade wing 2 provided by the present invention includes three fixed blade wings 21 distributed in a circular array at the head of the drill bit body 1, the head end of the fixed blade wing 21 is close to the center of the drill bit body 1 and its tail end extends to the side of the drill bit body 1, and the side of the drill bit body 1 is provided with three groups of intermediate movable blade wings 22 and three tail movable blade wings 23, the intermediate movable blade wing 22 includes an intermediate arc plate 221 nested with the drill bit body 1, and the intermediate arc plate 221 is provided with an intermediate The blade wing 222 and the tail movable blade wing 23 include a tail arc plate 231 nested with the drill body 1, and the tail arc plate 231 is provided with a tail blade wing 232 that cooperates with the middle blade wing 222. The middle movable blade wing 22 and the tail movable blade wing 23 can form three blades, six blades and nine blades with the fixed blade wing 21 through rotation adjustment. The middle arc plate 221 and the tail arc plate 231 are both provided with a plurality of positioning pins 5 connected to the drill body 1, and the positioning pins 5 are used for positioning the middle movable blade wing 22 and the tail movable blade wing 23.

[0030] More specifically, the three blades 2 are all designed in sections, the fixed blade 21 is fixed to the head of the drill bit by welding, and its position does not change, while the positions of the middle movable blade 22 and the tail movable blade 23 on the drill body 1 are adjustable. If the fixed blade 21, the middle movable blade 22 and the tail movable blade 23 are connected in sequence, the drill bit can have a three-blade structure; if the middle movable blade 22 and the tail movable blade 23 are connected in sequence and both are staggered with the fixed blade 21 at the same time, the drill bit can have a six-blade structure; if the fixed blade 21, the middle movable blade 22 and the tail movable blade 23 are all staggered, the drill bit can have a nine-blade structure. In this way, it can be adjusted to different blade states according to actual conditions, and no matter it is 3 blades, 6 blades or 9 blades, the fixed blade 21 at the front end of the drill bit direction can ensure that the drill bit has a good drilling ability, and in the state of 6 blades and 9 blades, it can improve the stability of the drill bit in soft-medium hard coal seams on the basis of ensuring the drilling rate, and reduce the probability of pump blocking. Further, if the drill bit is adjusted to the working state of 6 blades or 9 blades, the positioning ability of the nesting interface between the blade 2 and the drill body 1 and the positioning effect of the fixed pin can ensure that the drill bit has a high structural reliability, which is conducive to improving the working stability of the drill bit, and is conducive to extending the actual service life of the drill bit, thereby improving the comprehensive utilization rate of the blade 2.

[0031] In order to improve the drilling ability of the drill bit, a first step opening 211 is provided at the bottom of the fixed blade wing 21 provided by the present invention, a first wedge opening 212 is provided on the inner side of the first step opening 211, the first step opening 211 and the first wedge opening 212 are both blocking surfaces facing the working surface of the PDC blade 4, and a middle three-sided three-dimensional wing step 223 that is face-to-face matched with the first step opening 211 and the first wedge opening 212 is provided on the top of the middle movable blade wing 22. Among them, the top characteristics of the middle movable blade wing 22 match the bottom characteristics of the fixed blade wing 21. On the one hand, the middle movable blade wing 22 can maintain a good sealing surface after docking with the fixed blade wing 21. On the other hand, it can provide external force support for the top of the middle movable blade wing 22, reduce the wear of the top of the middle movable blade wing 22 under the three-blade wing 2 structure, which is beneficial to ensure a better working condition under 6 blade wings and 9 blade wings; on the other hand, when the drill bit is adjusted to the state of 6 blade wings or 9 blade wings, the head of the middle movable blade wing 22 can have a certain slope, which is beneficial to reduce the wear of the blade wing 2, so that the drilled layer can better contact with the PDC blade 4 on the middle movable blade wing 22 and complete cutting and crushing.

[0032] Furthermore, a second step opening 224 is provided at the bottom of the middle movable blade wing 22, and a second wedge opening 225 is provided on the inner side of the second step opening 224. The second step opening 224 and the second wedge opening 225 are both blocking surfaces facing the working surface of the PDC blade 4, and a tail section three-sided three-dimensional wing step 233 that is face-to-face matched with the second step opening 224 and the second wedge opening 225 is provided on the top of the tail section movable blade wing 23. Among them, the top characteristics of the tail movable blade wing 23 match the bottom characteristics of the middle movable blade wing 22. On the one hand, the tail movable blade wing 23 can maintain a good sealing surface after docking with the middle movable blade wing 22. On the other hand, it can provide external force support for the top of the tail movable blade wing 23, reduce the wear of the top of the tail movable blade wing 23 under the three-blade wing 2 structure, which is beneficial to ensure a better working condition under 6 blade wings and 9 blade wings; on the other hand, when the drill bit is adjusted to the state of 6 blade wings or 9 blade wings, the head of the tail movable blade wing 23 can have a certain slope, which is beneficial to reduce the wear of the blade wing 2, so that the drilled layer can better contact with the PDC blade 4 on the tail movable blade wing 23 and complete cutting and crushing.

[0033] In order to improve the working performance of the drill bit, the three-sided three-dimensional wing step 223 provided by the present invention includes a first wedge surface 223a that is connected to the side of the drill bit body 1 by an inclination, a first horizontal platform surface 223b is provided at the bottom of the first wedge surface 223a, a first inclined step surface 223c is provided on the side of the first wedge surface 223a and the first horizontal platform surface 223b, and a first supporting horizontal platform surface 223d is provided at the bottom of the first inclined step surface 223c. The three-sided three-dimensional wing step 233 of the tail section includes a first wedge surface 223a that is connected to the side of the drill bit body 1 by an inclination, a first horizontal platform surface 223b is provided at the bottom of the first wedge surface 223a and the first horizontal platform surface 223b, and a first supporting horizontal platform surface 223d is provided at the bottom of the first inclined step surface 223c. 1, a second wedge surface 233a is obliquely connected to the side surface of the PDC blade 4, a second horizontal platform surface 233b is arranged at the bottom of the second wedge surface 233a, a second inclined step surface 233c is arranged on the side of the second wedge surface 233a and the second horizontal platform surface 233b, a second supporting horizontal platform surface 233d is arranged at the bottom of the second inclined step surface 233c, and a cemented carbide body 26 is arranged on the edges of the middle three-sided three-dimensional wing steps 223 and the tail three-sided three-dimensional wing steps 233 facing the rotation working direction of the PDC blade 4. Among them, the middle three-sided three-dimensional wing step 223 can match the first step opening 211, the first wedge opening 212 and the tail end face of the fixed blade 21, and play a multi-faceted support role in the three-blade working state, which is conducive to improving the working performance of the middle movable blade 22 in the three-blade structure; the tail section three-sided three-dimensional wing step 233 can match the second step opening 224, the second wedge opening 225 and the tail end face of the middle movable blade 22, and play a multi-faceted support role in the three-blade working state, which is conducive to improving the working performance of the tail section movable blade 23 in the three-blade structure. The hard alloy body 26 on the middle three-sided three-dimensional wing step 223 and the tail section three-sided three-dimensional wing step 233 is arranged on multiple edges, which can effectively resist the working pressure from the drilling working surface, thereby improving the drilling ability and wear resistance of the drill bit, which is conducive to extending the actual service life of the drill bit.

[0034] In order to improve the structural reliability of the middle movable blade 22 and the tail segment movable blade 23 after being combined with the drill body 1, the present invention provides an embedding groove 6 corresponding to the middle arc plate 221 and the tail segment arc plate 231 on the side of the drill body 1, and the embedding groove 6 includes an outer ring segment 61, and a plurality of axially spaced inner ring segments 62 are provided on the side of the outer ring segment 61 facing the center of the drill bit, and the combined cross-section of the inner ring segment 62 and the outer ring segment 61 is T-shaped, and a circular ring segment 63 is provided on the inner ring segment 62, and the cross-sectional diameter of the circular ring segment 63 is greater than the axial depth of the inner ring segment 62, the outer side of the middle arc plate 221 and the outer side of the tail segment arc plate 231 are both located on the same conical surface as the side of the drill body 1, and the inner side of the middle arc plate 221 and the inner side of the tail segment arc plate 231 are both provided with a plurality of convex plates 24 corresponding to the inner ring segments 62, and the convex plates 24 are provided with annular protrusions 25 cooperating with the circular ring segments 63. In this case, in addition to using the locating pin 5 to locate the circumferential position of the middle movable blade wing 22 and the tail segment movable blade wing 23 on the drill bit body 1, the middle movable blade wing 22 and the tail segment movable blade wing 23 also establish a multi-node nesting relationship with the drill bit body 1, such as the middle arc plate 221 and the tail segment arc plate 231 are nested with the outer ring segment 61, the convex plate 24 is nested with the inner ring segment 62, and the annular protrusion 25 is nested with the circular ring segment 63. The multi-node nesting method can make the middle movable blade wing 22 and the tail segment movable blade wing 23 resist axial and radial pressure, especially the nesting of the annular protrusion 25 and the circular ring segment 63 can play a self-locking role, so that the middle movable blade wing 22 and the tail segment movable blade wing 23 have greater pressure resistance after being pressed onto the drill bit body; at the same time, the purpose of adjusting the form of the working wing of the drill bit can be achieved by moving the middle arc plate 221 and the tail segment arc plate 231 along the length direction of the embedding groove 6. In addition to the positioning function of multiple positioning pins 5, the positioning pins 5 are tapered pins and fit tightly with the pin holes. The tapered positioning pins 5 have certain radial and axial bearing strengths, strong compressive resistance, and good anti-slip effect. The middle movable blade wing 22 and the tail movable blade wing 23 can establish a stable assembly relationship on the drill body 1, and effectively improve the structural reliability of the drill bit during operation.

[0035] In order to improve the utilization rate of the drill bit, taking into account the needs of the staggered angles of adjacent blades in the 6-blade working form and the 9-blade working form, the present invention is provided with pin holes 7 for connecting the locating pins 5 on the drill bit body 1, and the number of pin holes 7 is a multiple of the number of locating pins 5 on the same horizontal surface. This can provide a larger adjustment margin for the relative positions of the middle movable blade 22 and the tail movable blade 23 on the drill bit body 1, so as to obtain 6-blade drill bits and 9-blade drill bits with different staggered angles.

[0036] In order to improve the drilling ability of the drill bit, the present invention provides a wear-resistant surfacing layer 8 distributed between adjacent fixed blades 21 at the head of the drill bit body 1, and the tail end of the wear-resistant surfacing layer 8 extends to the side of the drill bit body 1. By welding the wear-resistant surfacing layer 8 between the fixed blades 21, the wear resistance and pressure resistance of the head end of the drill bit body 1 can be effectively improved, and a certain welding length and welding surface are provided for the root of the fixed blade 21, which is beneficial to extending the actual service life of the drill bit.

[0037] In order to facilitate the efficient discharge of the drill cuttings generated in the drilling direction, in accordance with the rotary characteristics of the drill bit, the three blades 2 formed by the fixed blade 21, the middle active blade 22 and the tail active blade 23 provided by the present invention are in a spiral structure, and the middle active blade 22 and the tail active blade 23 in the form of a 6-blade drill bit and a 9-blade drill bit are on different spiral surfaces, with different spiral working diameters and working angles. This can improve the efficiency of the discharge of drill cuttings, reduce the wear on the blade 2, and reduce the workload of the PDC blade 4.

[0038] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A multi-stage adjustable drill bit for mining, comprising a drill bit body, an internal circulation cooling channel is arranged inside the drill bit body, a blade is arranged outside the drill bit body, a plurality of tooth seats distributed along the length direction of the blade are arranged on the blade, and a PDC blade is arranged on the tooth seat, characterized in that: The blade wings include three fixed blade wings distributed in a circular array on the head of the drill bit body, the head end of the fixed blade wings is close to the center of the drill bit body and the tail end thereof extends to the side of the drill bit body, the side of the drill bit body is provided with three groups of intermediate movable blade wings and three tail movable blade wings, the intermediate movable blade wings include an intermediate arc plate nested with the drill bit body, the intermediate arc plate is provided with an intermediate blade wing matched with the tail end of the fixed blade wing, the tail movable blade wing includes a tail arc plate nested with the drill bit body, the tail arc plate is provided with a tail blade wing, the intermediate movable blade wings and the tail movable blade wings can form three blade wings, six blade wings and nine blade wings with the fixed blade wings through rotation adjustment, the intermediate arc plate and the tail arc plate are both provided with a plurality of positioning pins connected to the drill bit body, and the positioning pins are used to position the intermediate movable blade wings and the tail movable blade wings.

2. A multi-stage adjustable drill bit for mining according to claim 1, characterized in that: A first step opening is provided at the bottom of the fixed blade, a first wedge opening is provided on the inner side of the first step opening, the first step opening and the first wedge opening are both blocking surfaces facing the working surface of the PDC blade, and a middle three-sided three-dimensional wing step that is face-to-face matched with the first step opening and the first wedge opening is provided on the top of the middle movable blade.

3. A multi-stage adjustable drill bit for mining according to claim 2, characterized in that: A second step opening is provided at the bottom of the middle movable blade, a second wedge opening is provided on the inner side of the second step opening, the second step opening and the second wedge opening are both blocking surfaces facing the working surface of the PDC blade, and a three-dimensional tail section wing step is provided on the top of the tail movable blade that is matched with the second step opening and the second wedge opening.

4. A multi-stage adjustable drill bit for mining according to claim 3, characterized in that: The three-sided three-dimensional wing step in the middle includes a first wedge surface obliquely connected to the side of the drill bit body, a first horizontal surface is arranged at the bottom of the first wedge surface, a first inclined step surface is arranged on the side of the first wedge surface and the first horizontal surface, and a first supporting horizontal surface is arranged at the bottom of the first inclined step surface; the three-sided three-dimensional wing step in the tail section includes a second wedge surface obliquely connected to the side of the drill bit body, a second horizontal surface is arranged at the bottom of the second wedge surface, a second inclined step surface is arranged on the side of the second wedge surface and the second horizontal surface, and a second supporting horizontal surface is arranged at the bottom of the second inclined step surface; the three-sided three-dimensional wing step in the middle and the three-sided three-dimensional wing step in the tail section are both provided with a cemented carbide body on the edges facing the rotating working direction of the PDC blade.

5. A multi-stage adjustable drill bit for mining according to claim 1, characterized in that: The side surface of the drill body is provided with an embedding groove corresponding to the middle arc plate and the tail arc plate, the embedding groove includes an outer ring segment, and the side of the outer ring segment facing the center of the drill bit is provided with a plurality of axially spaced inner ring segments, the combined cross-section of the inner ring segment and the outer ring segment is T-shaped, and a circular ring segment is provided on the inner ring segment, the cross-sectional diameter of the circular ring segment is greater than the axial depth of the inner ring segment, the outer side of the middle arc plate and the outer side of the tail arc plate are both located on the same conical surface as the side surface of the drill body, and the inner side of the middle arc plate and the inner side of the tail arc plate are both provided with a plurality of convex plates corresponding to the inner ring segments one by one, and the convex plate is provided with an annular protrusion matching the circular ring segment.

6. A multi-stage adjustable drill bit for mining according to claim 5, characterized in that: The drill body is provided with pin holes for connecting positioning pins, and the number of the pin holes is a multiple of the number of positioning pins on the same horizontal surface.

7. A multi-stage adjustable drill bit for mining according to claim 6, characterized in that: The positioning pin is a tapered pin and is tightly matched with the pin hole.

8. A multi-stage adjustable drill bit for mining according to claim 1, characterized in that: The head of the drill body is provided with a wear-resistant surfacing layer distributed between adjacent fixed blades, and the tail end of the wear-resistant surfacing layer extends to the side of the drill body.

9. A multi-stage adjustable drill bit for mining according to claim 1, characterized in that: The three blades formed by sequentially connecting the fixed blade, the middle movable blade and the tail movable blade in a spiral structure.

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