Underreaming drill bit and drilling equipment

Abstract

The utility model discloses an underreaming drill bit and drilling equipment, and relates to the technical field of drilling equipment, and the underreaming drill bit comprises a barrel, a telescopic rod, two telescopic beams, a guide assembly and two connecting rod assemblies. The telescopic rod comprises a sliding rod body and a cavity structure, the sliding rod body is slidably arranged in the barrel in the first direction, the two telescopic beams are slidably arranged in the cavity structure in the second direction, the guide assembly comprises a guide rod and a guide block, and the guide block is slidably arranged on the guide rod in the first direction. Each connecting rod assembly comprises a pull rod, a pressing rod and a stabilizing rod, one end of the pull rod is rotationally connected with the barrel, the other end of the pull rod is rotationally connected with one end of the pressing rod, the other end of the pressing rod is rotationally connected with the corresponding telescopic beam and one end of the stabilizing rod, and the other end of the stabilizing rod is rotationally connected with the guide block. The underreaming drill bit can obtain a larger expansion diameter, is suitable for construction of a special-shaped precast pile with a large diameter expansion ratio, meanwhile, the structure is more stable after the drill bit is expanded, and the construction efficiency is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of drilling equipment, and in particular to a bottom expansion drill bit and drilling equipment. Background Art

[0002] During the foundation construction process, the drilling and pipe following method is often used for precast pile construction. The general principle is: a long spiral drill rod equipped with a bottom expansion drill bit is inserted into the middle hole of the precast pile. During drilling, the bottom expansion drill bit drills a hole slightly larger than the outer diameter of the precast pile. The precast pile can follow the pile in the drilled hole by its own gravity. When the precast pile reaches the predetermined position, the bottom expansion drill bit is retracted and the drill rod is pulled out.

[0003] At present, the commonly used bottom expansion drill bit is a mechanical rotary wing bottom expansion drill bit that realizes the opening and closing of the drill bit by forward and reverse rotation. However, the use of a mechanical rotary wing bottom expansion drill bit has the following two main shortcomings:

[0004] Firstly, due to the limitation of its structural stability, the diameter expansion ratio is often relatively small, and the expanded hole diameter is slightly larger than the drill bit retraction diameter, which is not suitable for the construction of special-shaped precast piles that require a large diameter expansion ratio.

[0005] Secondly, the stability of opening and closing the drill bit through the forward and reverse rotation method is poor. When encountering obstruction, it is impossible to ensure that the drill bit is fully opened or closed, which reduces the construction efficiency. Utility Model Content

[0006] The purpose of the present application is to provide a bottom enlarging drill bit and a drilling device, which solve the problems of small application range and low construction efficiency of traditional bottom enlarging drill bits.

[0007] To achieve the above object, the present application provides a bottom expansion drill bit, comprising:

[0008] Cylinder, used to connect the drill pipe;

[0009] The telescopic rod comprises a sliding rod body and a cavity structure. The sliding rod body is slidably arranged in the cylinder body along a first direction, and the cavity structure is arranged at one end of the sliding rod body away from the cylinder body;

[0010] Two telescopic beams, the two telescopic beams are slidably arranged in the cavity structure along the second direction to extend outwards from the cavity structure or retract inwards into the cavity structure respectively;

[0011] A guide assembly is located inside the telescopic rod, the guide assembly includes a guide rod and a guide block, the guide rod includes a fixed portion and a guide portion, the fixed portion is fixedly connected to the cylinder, the guide portion is arranged at one end of the fixed portion away from the cylinder, the guide block is sleeved on the guide portion and slidably arranged on the guide portion along a first direction, a limiting portion is provided at one end of the guide rod away from the fixed portion, and the limiting portion and the fixed portion are used to limit the sliding position of the guide block;

[0012] Two groups of connecting rod assemblies, each group of connecting rod assemblies includes a pull rod, a pressure rod and a stabilizing rod, one end of the pull rod is rotatably connected to the cylinder, the other end of the pull rod is rotatably connected to one end of the pressure rod, the other end of the pressure rod is rotatably connected to the corresponding telescopic beam and one end of the stabilizing rod, and the other end of the stabilizing rod is rotatably connected to the guide block.

[0013] In some embodiments, a limit block is provided on the outer wall of one end of the sliding rod body away from the cavity structure, and a limit protrusion protruding inward is provided on the inner wall of the bottom end of the cylinder body. The limit protrusion contacts and abuts against the limit block to limit the sliding position of the telescopic rod.

[0014] In some embodiments, the sliding rod body is a polygonal structure, the bottom end of the cylinder body has a polygonal inner cavity, and the sliding rod body can be slidably embedded in the polygonal inner cavity to transmit the torque of the cylinder body to the telescopic rod.

[0015] In some embodiments, one of the two telescopic beams includes a first sliding body, and the other of the two telescopic beams includes a second sliding body. The first sliding body is slidably connected to the cavity structure, and the second sliding body is slidably connected to the first sliding body.

[0016] In some embodiments, the guide rod is connected to the bottom end of the cylinder body through a pin shaft, and waist-shaped long holes are provided on both sides of the telescopic rod for the pin shaft to pass through.

[0017] In some embodiments, a mounting seat is installed at the bottom end of the cavity structure, and a plurality of cutting heads are provided on the mounting seat and each pressure rod.

[0018] In some embodiments, the mounting seat has two mounting surfaces, which are respectively located on two sides of the mounting seat along the second direction, and the number of cutting bits installed on the two mounting surfaces is the same but at different angles.

[0019] In some embodiments, a joint is provided at the top of the cylinder, the joint is a polygonal structure, and the joint is used to connect the drill rod.

[0020] In some embodiments, nozzles are provided on the side and bottom of the cylinder, and the nozzles are used to spray high-pressure gas or liquid to clean the mud and sand on the telescopic rod, telescopic beam and connecting rod assembly.

[0021] The present application also provides a drilling device, including a drill rod and any one of the above-mentioned bottom expansion drill bits, wherein the bottom expansion drill bit is installed on the drill rod.

[0022] Compared with the above-mentioned background technology, the bottom expansion drill bit provided in the embodiment of the present application includes a barrel, a telescopic rod, two telescopic beams, a guide assembly and two groups of connecting rod assemblies. Among them, the cylinder is used to connect the drill rod, the telescopic rod includes a sliding rod body and a cavity structure, the sliding rod body is slidably arranged in the cylinder along a first direction, the cavity structure is arranged at one end of the sliding rod body away from the cylinder, and the two telescopic beams are slidably arranged in the cavity structure along a second direction to extend the cavity structure outward or retract the cavity structure inward respectively, the guide assembly is located in the telescopic rod, the guide assembly includes a guide rod and a guide block, the guide rod includes a fixed part and a guide part, the fixed part is fixedly connected to the cylinder, the guide part is arranged at one end of the fixed part away from the cylinder, the guide block is sleeved on the guide part and is slidably arranged on the guide part along the first direction, a limiting part is provided at one end of the guide rod away from the fixed part, the limiting part and the fixed part are used to limit the sliding position of the guide block, each group of connecting rod assemblies includes a pull rod, a pressure rod and a stabilizing rod, one end of the pull rod is rotatably connected to the cylinder, the other end of the pull rod is rotatably connected to one end of the pressure rod, the other end of the pressure rod is rotatably connected to the corresponding telescopic beam and one end of the stabilizing rod, and the other end of the stabilizing rod is rotatably connected to the guide block. Taking into account the actual application scenarios of the drill bit, the first direction may be a vertical direction, and the second direction may be a horizontal direction.

[0023] When the drill bit drills downward, the ground exerts an upward force on the drill bit, causing the telescopic rod to move upward, the pull rod and the pressure rod to make circular motions that expand outward, and the guide block to rise along the guide portion until the guide block contacts the fixed portion, and the pull rod and the pressure rod are fully deployed. At this time, the telescopic rod continues to move upward, and the stabilizing rod makes circular motions that expand outward, while driving the two telescopic beams to slide outwards respectively. When the guide block contacts the telescopic rod, the drill bit is fully deployed. During the entire drilling process, the ground always exerts an upward force on the drill bit, and the drill rod exerts downward pressure on the drill bit, making the multi-link form a more stable structure.

[0024] The working principle of drill bit retraction is as follows: lift the drill bit upward, when the pull rod contacts the bottom of the precast pile, the wall of the precast column applies force to the pull rod, the pull rod and the pressure rod respectively make inward retraction circular motions, the telescopic rod slides downward, and the stabilizing rod makes inward retraction circular motions, driving the two telescopic beams to slide inwards respectively until they are completely retracted into the cavity structure, at this time continue to lift the drill rod upward, the wall of the precast column continues to contact the pull rod and apply force, the pull rod and the pressure rod respectively make inward retraction circular motions, until the drill bit is completely retracted and lifted out of the middle hole of the precast pile.

[0025] With such an arrangement, on the one hand, the left and right telescopic beams slide outward, driving the hinge point of the compression rod to move outward, thereby obtaining a larger unfolded diameter, which is suitable for the construction of special-shaped precast piles with a large expansion ratio; on the other hand, the linkage function of the multi-link structure makes the structure more stable after the drill bit is unfolded, which is conducive to the drilling work and ensures the efficiency of the construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the overall structure of the bottom expansion drill bit in the embodiment of the present application;

[0028] Figure 2 for Figure 1 A front view of the bottom enlargement drill bit shown;

[0029] Figure 3 for Figure 2 A cross-sectional view of

[0030] Figure 4 This is a schematic diagram of the expansion process of the bottom expansion drill bit in the embodiment of the present application;

[0031] Figure 5 This is a schematic diagram of the bottom expansion drill bit retracting process in an embodiment of the present application.

[0032] in:

[0033] 10-cylinder, 11-limiting protrusion, 12-polygonal inner cavity, 13-connector, 14-adapter;

[0034] 20-telescopic rod, 21-sliding rod body, 211-waist-shaped long hole, 22-cavity structure, 23-limiting block, 24-mounting seat, 241-mounting surface;

[0035] 30- telescopic beam, 31- first sliding body, 32- second sliding body;

[0036] 40-guide assembly, 41-guide rod, 411-fixing portion, 412-guide portion, 413-limiting portion, 42-guide block, 43-pin shaft;

[0037] 50-connecting rod assembly, 51-pull rod, 52-pressure rod, 53-stabilizing rod, 54-first rotating shaft, 55-second rotating shaft, 56-third rotating shaft, 57-fourth rotating shaft;

[0038] 60- blade;

[0039] 70-Nozzle. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0042] It should be noted that the directional words such as "upper end, lower end, left side, right side" described below are all defined based on the drawings in the specification.

[0043] See also Figure 1 , Figure 2 and Figure 3 The bottom enlarging drill bit provided in the embodiment of the present application includes a barrel 10, a telescopic rod 20, two telescopic beams 30, a guide assembly 40 and two sets of connecting rod assemblies 50.

[0044] The cylinder 10 is used to connect the drill rod. A joint 13 is provided at the top of the cylinder 10. The joint 13 is a polygonal structure. The joint 13 is used to connect the drill rod and to transmit the torque of the drill rod. Adapter seats 14 are provided on both sides of the cylinder 10. The interior of the cylinder 10 is a cavity structure, and the bottom end of the cylinder 10 is a polygonal hollow structure.

[0045] The telescopic rod 20 is a hollow structure. The telescopic rod 20 includes a sliding rod body 21 and a cavity structure 22. The sliding rod body 21 can be slidably arranged in the cylinder 10 along a first direction. The sliding rod body 21 is a polygonal structure. Accordingly, the bottom end of the cylinder 10 has a polygonal inner cavity 12. The sliding rod body 21 can be slidably embedded in the polygonal inner cavity 12 to transmit the torque of the cylinder 10 to the telescopic rod 20, that is, the sliding rod body 21 is the same polygonal structure as the bottom end of the cylinder 10, thereby transmitting the torque of the cylinder 10 to the telescopic rod 20. The cavity structure 22 is arranged at one end of the sliding rod body 21 away from the cylinder 10. The cavity structure 22 has a sliding cavity inside for the two telescopic beams 30 to slide.

[0046] The two telescopic beams 30 are slidably arranged in the cavity structure 22 along the second direction to extend outward from the cavity structure 22 or retract inward from the cavity structure 22, respectively. That is, the left and right telescopic beams 30 can slide outward or inward along the cavity structure 22. In order to reduce the external dimensions of the drill bit after it is retracted, the left and right telescopic beams 30 are overlapped with each other.

[0047] The guide assembly 40 is located in the telescopic rod 20. The guide assembly 40 includes a guide rod 41 and a guide block 42. The guide rod 41 includes a fixed portion 411 and a guide portion 412. The fixed portion 411 is fixedly connected to the cylinder 10. The guide portion 412 is arranged at one end of the fixed portion 411 away from the cylinder 10. The guide block 42 is sleeved on the guide portion 412 and can be slidably arranged on the guide portion 412 along a first direction. A limiting portion 413 is provided at one end of the guide rod 41 away from the fixed portion 411. The limiting portion 413 and the fixed portion 411 are used to limit the sliding position of the guide block 42.

[0048] Each connecting rod assembly 50 includes a pull rod 51, a pressure rod 52 and a stabilizing rod 53. One end of the pull rod 51 is rotatably connected to the cylinder 10, and the other end of the pull rod 51 is rotatably connected to one end of the pressure rod 52. The other end of the pressure rod 52 is rotatably connected to the corresponding telescopic beam 30 and one end of the stabilizing rod 53. The other end of the stabilizing rod 53 is rotatably connected to the guide block 42.

[0049] Taking into account the actual application scenarios of the drill bit, the first direction may be a vertical direction, and the second direction may be a horizontal direction.

[0050] When the drill bit drills downward, the ground exerts an upward force on the drill bit, causing the telescopic rod 20 to move upward, the pull rod 51 and the pressure rod 52 to respectively perform an outwardly expanding circular motion, and the guide block 42 rises along the guide portion 412 until the guide block 42 contacts the fixed portion 411, and the pull rod 51 and the pressure rod 52 are fully deployed. At this time, the telescopic rod 20 continues to move upward, and the stabilizing rod 53 performs an outwardly expanding circular motion, while driving the two telescopic beams 30 to slide outwardly respectively. When the guide block 42 contacts the telescopic rod 20, the drill bit is fully deployed. During the entire drilling process, the ground always exerts an upward force on the drill bit, and the drill rod exerts downward pressure on the drill bit, so that the multi-link forms a relatively stable structure.

[0051] The working principle of drill bit retraction is specifically as follows: the drill bit is lifted upward, and when the pull rod 51 contacts the bottom of the precast pile, the wall of the precast column applies a force to the pull rod 51, and the pull rod 51 and the pressure rod 52 respectively make inward retraction circular motions, the telescopic rod 20 slides downward, and the stabilizing rod 53 makes inward retraction circular motions, driving the two telescopic beams 30 to slide inwards respectively until they are completely retracted into the cavity structure 22, and at this time, the drill rod continues to be lifted upward, and the wall of the precast column continues to contact and apply a force to the pull rod 51, and the pull rod 51 and the pressure rod 52 respectively make inward retraction circular motions until the drill bit is completely retracted and lifted out of the middle hole of the precast pile.

[0052] With such arrangement, on the one hand, the hinge point of the compression rod 52 is driven to move outward by the outward sliding of the left and right telescopic beams 30, thereby obtaining a larger unfolded diameter, which is suitable for the construction of special-shaped prefabricated piles with a large expansion ratio. On the other hand, the linkage function of the multi-link structure makes the structure more stable after the drill bit is unfolded, which is conducive to the drilling work and ensures the efficiency of the construction.

[0053] In order to facilitate limiting the sliding of the telescopic rod 20, a limit block 23 is provided on the outer wall of one end of the sliding rod body 21 away from the cavity structure 22. The limit block 23 can slide up and down in the cylinder 10. The inner wall of the bottom end of the cylinder 10 is provided with a limit protrusion 11 protruding inward. The limit protrusion 11 contacts and abuts against the limit block 23 to limit the sliding position of the telescopic rod 20.

[0054] In this way, when the limiting protrusion 11 contacts and abuts against the limiting block 23 , the telescopic rod 20 can be limited, thereby achieving the purpose of limiting the sliding position of the telescopic rod 20 in the barrel 10 .

[0055] To facilitate overlapping of the two telescopic beams 30, one of the two telescopic beams 30 includes a first sliding body 31, and the other telescopic beam 30 includes a second sliding body 32. The first sliding body 31 is slidably connected to the cavity structure 22, and the second sliding body 32 is slidably connected to the first sliding body 31.

[0056] In this way, when the stabilizing rods 53 on both sides respectively perform outwardly expanding circular motion, the two telescopic beams 30 can be driven to slide outwardly respectively at the same time, and when the stabilizing rods 53 on both sides perform inwardly retracting circular motion, the two telescopic beams 30 can be driven to slide inwardly respectively until they are completely retracted into the cavity structure 22. By sliding the left and right telescopic beams 30 outwardly, the hinge point of the compression rod 52 is driven to move outward, thereby obtaining a larger expansion diameter, which is suitable for the construction of special-shaped prefabricated piles with a large expansion ratio.

[0057] In some embodiments, to facilitate the sliding of the telescopic rod 20 relative to the guide rod 41, the guide rod 41 is connected to the bottom end of the cylinder 10 through a pin 43, and waist-shaped long holes 211 are provided on both sides of the telescopic rod 20 for the pin 43 to pass through.

[0058] In order to facilitate installation of the cutter head 60 at the bottom of the telescopic rod 20 , a mounting seat 24 is installed at the bottom end of the cavity structure 22 , and the mounting seat 24 is provided with a plurality of cutter heads 60 arranged in a certain pattern.

[0059] In addition, each pressure rod 52 is provided with a plurality of cutter heads 60 arranged in a certain pattern, which is beneficial for drilling by the drill bit.

[0060] Specifically, the mounting seat 24 has two mounting surfaces 241 , which are respectively located on both sides of the mounting seat 24 along the second direction. Both mounting surfaces 241 are inclined surfaces, and the number of tool bits 60 installed on the two mounting surfaces 241 is the same but at different angles.

[0061] In some embodiments, the two mounting surfaces 241 are symmetrically distributed about the axis of the mounting seat 24 , and the cutter head 60 on the mounting surface 241 is perpendicular to the mounting surface 241 .

[0062] In some embodiments, in each set of connecting rod assemblies 50, one end of the pull rod 51 is connected to the transfer seat 14 on the cylinder 10 through the first rotating shaft 54, and the other end is connected to one end of the pressure rod 52 through the second rotating shaft 55. The other end of the pressure rod 52 is connected to one end of the telescopic beam 30 and the stabilizing rod 53 on the corresponding side through the third rotating shaft 56, thereby forming a multi-link structure. The other end of the stabilizing rod 53 is connected to the guide block 42 through the fourth rotating shaft 57, and the guide block 42 can slide up and down along the axial direction inside the telescopic rod 20.

[0063] In some embodiments, nozzles 70 are provided on the side and bottom of the cylinder 10 , and the nozzles 70 are used to spray high-pressure gas or liquid to clean the mud and sand on the telescopic rod 20 , the telescopic beam 30 and the connecting rod assembly 50 .

[0064] It can be understood that during the process of deploying or retracting the drill bit, in order to prevent the various moving units from being obstructed by mud, sand and stones, high-pressure gas or liquid is rushed into the drill bit, and the high-pressure gas or liquid is sprayed from the nozzle 70 to clear the mud, sand and stones on the running track of each moving unit, so that the process of deploying or retracting the drill bit can proceed smoothly without being blocked.

[0065] The drill bit expansion working principle is as follows Figure 4 As shown: when the drill bit is drilling downward, the ground exerts an upward force on the drill bit, causing the telescopic rod 20 to move upward along the axial direction, and the pull rod 51 and the pressure rod 52 respectively make outward circular motions along the first rotating shaft 54 ​​and the third rotating shaft 56, until the guide block 42 contacts the fixed portion 411 of the guide rod 41, and the pull rod 51 and the pressure rod 52 are fully deployed. At this time, the telescopic rod 20 continues to move upward along the axial direction, and the stabilizing rod 53 makes outward circular motions along the fourth rotating shaft 57, while driving the left and right telescopic beams 30 to slide outward. When the guide block 42 contacts the telescopic rod 20, the drill bit is fully deployed. During the entire drilling process, the ground always exerts an upward force on the drill bit, and the drill rod exerts downward pressure on the drill bit, so that the multi-link forms a relatively stable structure.

[0066] The drill bit retraction works as follows Figure 5 As shown: the drill bit is lifted upward, when the pull rod 51 contacts the bottom of the precast pile, the wall of the precast column applies a force to the pull rod 51, and the pull rod 51 and the pressure rod 52 respectively make an inward retracting circular motion along the first rotating shaft 54 ​​and the third rotating shaft 56, the telescopic rod 20 slides downward, and the stabilizing rod 53 makes an inward retracting circular motion along the fourth rotating shaft 57, driving the left and right telescopic beams 30 to slide inward until they are completely in contact with the telescopic rod 20. At this time, the drill rod continues to be lifted upward, and the wall of the precast column continues to contact and apply a force to the pull rod 51, and the pull rod 51 and the pressure rod 52 respectively make an inward retracting circular motion along the first rotating shaft 54 ​​and the third rotating shaft 56 until the drill bit is completely retracted and lifted out of the middle hole of the precast pile.

[0067] In summary, the bottom expansion drill bit provided in the embodiment of the present application completes the deployment and retraction of the drill bit through the force exerted on the drill bit by the ground and the wall of the precast pile pipe, and uses high-pressure gas and liquid to remove obstacles such as sand, stone, and soil. The whole process is more reliable and more efficient. At the same time, by sliding the left and right telescopic beams 30 outward, the hinge point of the pressure rod 52 is driven to move outward to obtain a larger deployment diameter, which is suitable for the construction of special-shaped precast piles with a large expansion ratio. In addition, through the linkage function of the multi-link structure, the structure of the drill bit is more stable after deployment, which is conducive to the drilling work and ensures the efficiency of construction.

[0068] The present application provides a drilling device, including a drill rod and a bottom-expanding drill bit as described in the above specific embodiment, wherein the bottom-expanding drill bit is installed on the drill rod; other parts of the drilling device can refer to relevant technologies and will not be elaborated in this article.

[0069] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0070] The bottom expansion drill bit and drilling equipment provided by the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the scheme and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the present application.

Claims

1. A bottom expansion drill bit, characterized in that: include: Cylinder, used to connect the drill pipe; A telescopic rod, the telescopic rod comprising a sliding rod body and a cavity structure, the sliding rod body being slidably arranged in the cylinder along a first direction, and the cavity structure being arranged at one end of the sliding rod body away from the cylinder; Two telescopic beams, the two telescopic beams are slidably arranged in the cavity structure along a second direction to respectively extend outward from the cavity structure or retract inward from the cavity structure; A guide assembly is located inside the telescopic rod, the guide assembly includes a guide rod and a guide block, the guide rod includes a fixed portion and a guide portion, the fixed portion is fixedly connected to the cylinder, the guide portion is arranged at one end of the fixed portion away from the cylinder, the guide block is sleeved on the guide portion and slidably arranged on the guide portion along the first direction, a limiting portion is provided at one end of the guide rod away from the fixed portion, and the limiting portion and the fixed portion are used to limit the sliding position of the guide block; Two groups of connecting rod assemblies, each group of connecting rod assemblies includes a pull rod, a pressure rod and a stabilizing rod, one end of the pull rod is rotatably connected to the cylinder, the other end of the pull rod is rotatably connected to one end of the pressure rod, the other end of the pressure rod is rotatably connected to the corresponding telescopic beam and one end of the stabilizing rod, and the other end of the stabilizing rod is rotatably connected to the guide block.

2. The bottom enlarging drill bit according to claim 1, characterized in that: A limit block is provided on the outer wall of one end of the sliding rod body away from the cavity structure, and a limit protrusion protruding inward is provided on the inner wall of the bottom end of the cylinder body. The limit protrusion contacts and abuts against the limit block to limit the sliding position of the telescopic rod.

3. The bottom enlarging drill bit according to claim 2, characterized in that: The sliding rod body is a polygonal structure, the bottom end of the cylinder body has a polygonal inner cavity, and the sliding rod body can be slidably embedded in the polygonal inner cavity to transmit the torque of the cylinder body to the telescopic rod.

4. The bottom enlarging drill bit according to claim 1, characterized in that: One of the two telescopic beams includes a first sliding body, and the other of the two telescopic beams includes a second sliding body. The first sliding body is slidably connected to the cavity structure, and the second sliding body is slidably connected to the first sliding body.

5. The bottom enlarging drill bit according to claim 1, characterized in that: The guide rod is connected to the bottom end of the cylinder through a pin shaft, and waist-shaped long holes for the pin shaft to pass through are arranged on both sides of the telescopic rod.

6. The bottom enlarging drill bit according to claim 1, characterized in that: A mounting seat is installed at the bottom end of the cavity structure, and a plurality of cutter heads are arranged on the mounting seat and each of the pressure rods.

7. The bottom enlarging drill bit according to claim 6, characterized in that: The mounting seat has two mounting surfaces, and the two mounting surfaces are respectively located on two sides of the mounting seat along the second direction. The number of the cutting bits installed on the two mounting surfaces is the same, but the angles are different.

8. The bottom enlarging drill bit according to claim 1, characterized in that: A joint is provided at the top of the cylinder, the joint is a polygonal structure, and the joint is used to connect a drill rod.

9. The bottom enlarging drill bit according to any one of claims 1 to 8, characterized in that: The side surface and the bottom surface of the cylinder are both provided with nozzles, and the nozzles are used to spray high-pressure gas or liquid to clean the mud and sand on the telescopic rod, the telescopic beam and the connecting rod assembly.

10. A drilling device comprising a drill rod, characterized in that: It also includes a bottom expansion drill bit as described in any one of claims 1 to 9, wherein the bottom expansion drill bit is installed on the drill rod.

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