Roller bit for efficiently breaking rocks

Abstract

The invention belongs to the technical field of roller bit drilling tools, and particularly provides an efficient rock breaking roller bit which comprises a roller bit body, a centralizer and a crushing assembly, the lower end of the centralizer is detachably connected with the roller bit body, and the crushing assembly is arranged at the top of a centralizing unit. When the drill bit is lifted and stuck, the top of the centralizer can be in contact with the hole shrinkage position, and the hole shrinkage position can be crushed through the crushing assembly at the moment. The diameter of the drill hole at the hole shrinkage position after being crushed by the crushing assembly can be enlarged to be the same as or larger than the size of the original drill hole, so that the centralizer and the cone drill body can smoothly pass through. According to the roller bit, the centralizer and the roller bit body are detachably connected, the crushing assembly is arranged on the centralizer, the roller bit body can be replaced after being abraded and scrapped, and the centralizer and the crushing assembly can be continuously used. By means of the arrangement, the roller bit can have the drill jamming prevention function, efficient construction is guaranteed, and the situation that the production cost and the use cost are greatly increased due to the fact that the crushing assembly is arranged is avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of roller bits, and particularly relates to a high-efficiency rock-breaking roller bit. BACKGROUND

[0002] Roller bits, PDC bits, rotary drilling bits, etc. all belong to drilling tools, and can be used in the fields of geological drilling, stratum sampling, oil and gas field drilling, pile foundation excavation, pipeline construction, etc. The most common form of the roller bit is a three-roller bit, which is composed of a bit body, three blades, and a roller installed on each blade. Adjacent two blades have a chip groove, the bit body has a flow channel communicating with the chip groove, a nozzle is installed at the outlet of the flow channel, drilling fluid enters the flow channel of the bit from the drill string, and then is sprayed from the three nozzles for cleaning the rock cuttings generated by the bit drilling.

[0003] During drilling, if uneven geological strata are encountered, a pipe sticking accident is likely to occur. For example, in a broken rock stratum, hole wall falling blocks are likely to occur. In a soft stratum, hole wall shrinkage is likely to occur, resulting in a reduced drilling hole size. Pipe sticking will cause the bit to be stuck and unable to be pulled up, the bit is difficult to be pulled back in time, and the construction efficiency is affected.

[0004] The prior art has some solutions to the technical problem of pipe sticking, for example, a cutting tooth is arranged at the rear end of the blade, the tooth tip of the cutting tooth faces upward, and if a falling block or shrinkage is encountered during pipe pulling, the cutting tooth can break the obstacle. However, this structure has the following disadvantages: the roller bit is a consumable, and needs to be replaced when it is worn to a certain extent. The above-mentioned measure in the prior art arranges the cutting tooth at the rear end of the blade, which can prevent pipe sticking, but when the roller is worn, the entire roller bit needs to be replaced. Since pipe sticking is an event that occurs with a small probability, if a cutting tooth is arranged on each produced roller bit to prevent occasional pipe sticking, the production cost of the bit will be greatly increased due to the fact that the cutting tooth is made of expensive wear-resistant metal material. Moreover, in actual application, the bit may have been worn to a scrap level before a pipe sticking accident occurs. SUMMARY

[0005] Based on the above technical problem, the present application provides a high-efficiency rock-breaking roller bit, which aims to solve the problem that the production cost of a single bit is increased due to the measure of arranging a cutting tooth at the rear end of the roller bit in the prior art to prevent pipe sticking.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is to provide a high-efficiency rock-breaking roller bit, which comprises:

[0007] a roller bit body;

[0008] The centralizer comprises a connecting column and a centralizing unit, a lower end of the connecting column is detachably connected with an upper end of the roller bit body, an inner portion of the connecting column is formed with a liquid inlet channel communicated with an inner flow channel of the roller bit, and the centralizing unit is coaxially arranged on an outer periphery of the connecting column.

[0009] A crushing assembly is arranged at a top portion of the centralizing unit, and a crushing diameter of the crushing assembly is greater than or equal to a drilling diameter of the roller bit body.

[0010] In a possible implementation, an annular adjusting cavity is formed at a top portion of the centralizing unit and surrounds the connecting column, a side wall of the liquid inlet channel is formed with an outlet hole and an inlet hole respectively communicated with the adjusting cavity, the outlet hole is located above the inlet hole, and a partition portion is arranged in the liquid inlet channel for partitioning the inlet hole and the outlet hole;

[0011] The crushing assembly comprises a hydraulic drive unit and a plurality of crushing units, the hydraulic drive unit is arranged at a top portion of the centralizer, a lower portion of the hydraulic drive unit is in sliding fit with the adjusting cavity and has a pressure chamber, an upper portion of the hydraulic drive unit has a contact portion with a same diameter as the centralizer, the hydraulic drive unit has an upper dead point and a lower dead point, when being at the upper dead point, the pressure chamber is arranged in an upper-lower staggered manner with the outlet hole and the inlet hole respectively, and when being at the lower dead point, the pressure chamber is communicated with the outlet hole and is arranged in a staggered manner with the inlet hole;

[0012] The plurality of crushing units are arranged in a circumferential direction above the contact portion, and the hydraulic drive unit is used to drive the plurality of crushing units to move in a radial direction of the contact portion.

[0013] In a possible implementation, the hydraulic drive unit comprises:

[0014] A mounting seat is arranged at a top portion of the centralizer, a lower portion of the mounting seat is in sliding fit with the adjusting cavity and jointly encloses the pressure chamber with the connecting column, an upper portion of the mounting seat extends to outside of the adjusting cavity and jointly encloses a sliding cavity with the connecting column, the mounting seat has an overflow hole communicated with the adjusting cavity and the sliding cavity, a side wall of the sliding cavity is formed with a plurality of mounting grooves penetrating a wall thickness thereof in a circumferential direction, and the plurality of crushing units are arranged in one-to-one correspondence with the mounting grooves; and the mounting seat has the contact portion.

[0015] A piston is in sliding fit in the sliding cavity, an upper portion of the piston is a conical surface and is in contact fit with a side of the crushing unit extending to the sliding cavity; and

[0016] A first elastic member is arranged between the mounting seat and the centralizing unit and is configured to provide a supporting force to keep the mounting seat at the top dead center position.

[0017] In a possible implementation, the crushing unit comprises:

[0018] A crushing tooth has a moving part in sliding fit with the mounting groove and a crushing part facing the borehole wall, and the moving part is in contact fit with the conical surface; and

[0019] A second elastic member is arranged between the moving part and the mounting seat and is configured to provide a pre-tightening force to move the crushing tooth towards the central axis of the mounting seat.

[0020] In a possible implementation, the side wall of the sliding cavity is provided with a plurality of pressure relief holes spaced apart along the circumference of the side wall, the pressure relief holes pass through the wall thickness, the pressure relief holes are located between two adjacent crushing teeth, and the pressure relief holes are lower than the highest position at which the piston can move.

[0021] In a possible implementation, the crushing tooth is one of a roller and a PDC cutting tooth.

[0022] In a possible implementation, the first elastic member is an elastic telescopic rod, one end of the elastic telescopic rod is connected to the mounting seat, and the other end of the elastic telescopic rod is connected to the centralizing unit.

[0023] In a possible implementation, the liquid inlet hole, the liquid outlet hole, and the flow passage are each provided with a plurality of holes spaced apart along the circumference of the connecting column.

[0024] In a possible implementation, the outer circumferential surface of the centralizing unit is provided with a spiral-shaped chip removal channel, the chip removal channel passes through the centralizing unit from top to bottom, and the lower end of the chip removal channel is in one-to-one correspondence with the chip removal groove of the roller bit body.

[0025] In a possible implementation, a gauge portion is defined between two adjacent chip removal channels, and the outer surface of the gauge portion is provided with gauge teeth.

[0026] Compared with the prior art, the high-efficiency roller bit provided by the application has the following advantages:

[0027] The high-efficiency rock breaking roller bit provided by the application comprises a roller bit body, a centralizer and a breaking assembly. The lower end of the centralizer is detachably connected with the roller bit body through a connecting column. The top of the centralizer is provided with the breaking assembly. The centralizer can drive the breaking assembly to move or rotate together. When the bit is pulled up and stuck, the top of the centralizer will contact with the reduced diameter position. At this time, the reduced diameter position can be broken by the breaking assembly. Since the breaking diameter of the breaking assembly during work is greater than or equal to the drilling diameter, the drilling diameter of the reduced diameter position after being broken by the breaking assembly can be expanded to the same or larger than the original drilling size, so that the centralizer and the roller bit body can pass through smoothly, avoiding the construction delay caused by sticking, and helping to improve the construction efficiency. The centralizer and the roller bit body are detachably connected, and the breaking assembly is arranged on the centralizer. After the roller bit body is worn out and scrapped, it can be replaced. Since the service life of the centralizer is longer than that of the roller bit body, the breaking assembly can be used for a longer time. In this way, the roller bit has the anti-sticking function, ensuring efficient construction, and the production and use cost will not be greatly increased due to the arrangement of the breaking assembly, achieving two purposes at one time. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0029] Figure 1 A perspective view of a high-efficiency rock breaking roller bit provided by the application;

[0030] Figure 2 A sectional view of a breaking assembly of a high-efficiency rock breaking roller bit provided by the application in a contracted state Figure 1 ;

[0031] Figure 3 A partial enlarged view of A part in Figure 2 ;

[0032] Figure 4 A sectional view of a breaking assembly of a high-efficiency rock breaking roller bit provided by the application in an expanded state

[0033] Figure 5 A partial enlarged view of B part in Figure 4 ;

[0034] Figure 6 A sectional view of a breaking assembly of a high-efficiency rock breaking roller bit provided by the application in a contracted state Figure 2 ;

[0035] Figure 7 For Figure 6 Partial enlarged view of middle C part;

[0036] Reference signs:

[0037] 10, bit body; 11, chip flute; 20, centralizer; 21, connecting column; 211, liquid outlet hole; 212, liquid inlet hole; 213, separation part; 214, liquid inlet channel; 22, centralizing unit; 221, chip removal channel; 222, gage part; 223, gage tooth; 23, limiting ring; 30, crushing assembly; 31, hydraulic drive unit; 311, mounting seat; 3111, pressure chamber; 3112, sliding cavity; 3113, overflow hole; 3114, contact part; 3115, pressure relief hole; 312, piston; 3121, conical surface; 313, first elastic member; 32, crushing unit; 321, crushing tooth; 3211, moving part; 3212, crushing part; 322, second elastic member. DETAILED DESCRIPTION

[0038] In order to make the technical problems to be solved by the present application, the technical solutions and beneficial effects clearer, the present application will be further described in detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0039] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0040] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0041] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of", "several" is two or more, unless otherwise explicitly specified.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0043] Please refer to Figures 1 to 7 , the following will be described with a high efficiency rock breaking roller bit provided by the embodiments of the application.

[0044] Please refer to Figure 1 and Figure 2 , the embodiments of the application provide a high efficiency rock breaking roller bit, which comprises a roller bit body 10, a centralizer 20 and a crushing assembly 30. The roller bit body 10 is a three-roller or other form of roller bit in the prior art, and a chip groove 11 is formed between two adjacent rollers. The inside of the roller bit body 10 has a flow channel for the flow of drilling fluid. The centralizer 20 comprises a connecting column 21 and a centralizing unit 22. The lower end of the connecting column 21 is detachably connected to the upper end of the roller bit body 10. The inside of the connecting column 21 is formed with a liquid inlet passage 214 that communicates with the internal flow channel of the roller bit. The centralizing unit 22 is coaxially arranged on the outer periphery of the connecting column 21. The crushing assembly 30 is arranged at the top of the centralizer 20. The crushing assembly 30 has a contracted state and an expanded state. When in the expanded state, the crushing diameter of the crushing assembly 30 is greater than or equal to the drilling diameter of the roller bit body 10.

[0045] Compared with the prior art, the high efficiency rock breaking roller bit provided by the embodiments of the application has the following beneficial effects:

[0046] The high efficiency rock breaking roller bit provided by the embodiments of the application comprises a roller bit body 10, a centralizer 20 and a crushing assembly 30. The lower end of the centralizer 20 is detachably connected to the roller bit body 10 through the connecting column 21. The top of the centralizing unit 22 is provided with the crushing assembly 30. The centralizer 20 can drive the crushing assembly 30 to move or rotate together. When the drill string is stuck during the upward movement of the drill bit, the top of the centralizer 20 will contact the reduced diameter position. At this time, the reduced diameter position can be crushed by the crushing assembly 30. Since the crushing diameter of the crushing assembly 30 during operation is greater than or equal to the drilling diameter, the drilling diameter of the reduced diameter position after crushing by the crushing assembly 30 can be expanded to the same size as the original drilling size or larger, so that the centralizer 20 and the roller bit body 10 can pass smoothly, avoiding the delay of construction caused by the stuck drill string, and helping to improve the construction efficiency.

[0047] In this embodiment, the centralizer 20 and the roller cone drill body 10 are detachably connected, and the crushing component 30 is mounted on the centralizer 20. The roller cone drill body 10 can be replaced after wear and tear, while the centralizer 20 and the crushing component 30 can continue to be used. Since the centralizer 20 has a longer lifespan than the roller cone drill body 10, the crushing component 30 can function for a longer period. This design not only provides the roller cone drill bit with anti-jamming functionality, ensuring efficient construction, but also avoids a significant increase in production and operating costs due to the inclusion of the crushing component 30, achieving two goals at once.

[0048] The roller cone drill body 10 can be directly selected from existing roller cone drill bits on the market, such as tricone drill bits. The roller cone drill body 10 is detachably connected to the lower end of the connecting post 21, which can be done by means of threaded connection, etc. It can be replaced after it wears down to a certain extent.

[0049] The stabilizer 20 is used to conform to the inner wall of the borehole during the downward drilling of the roller cone drill body 10, providing alignment and guidance, which helps to improve the stability of the drilling process and the verticality of the borehole. The stabilizer 20 includes a connecting post 21 and a stabilizer unit 22, which can be fixedly connected as a whole by welding or other methods. The lower end of the connecting post 21 is used for detachable connection with the roller cone drill body 10, and the upper end of the connecting post 21 is used for connection with the drill rod.

[0050] The centering unit 22 is disposed on the outer peripheral wall of the connecting column 21. The diameter of the centering unit 22 is adapted to the borehole diameter, and it can fit and guide the borehole inner wall during drilling. The axial length of the centering unit 22 should not be less than the length of the roller cone drill body 10, which helps to prevent borehole axis deviation and ensures that the verticality of the borehole is within a reasonable range.

[0051] The crushing component 30 is positioned on top of the straightening unit 22, such as... Figure 2 and Figure 4 The crushing component 30 has a contracted state and an expanded state. During normal drilling or lifting, the crushing component 30 is in the contracted state, the crushing unit 32 is not working, and the overall diameter of the crushing component 30 is smaller than the borehole diameter.

[0052] like Figure 1 and Figure 2 When in the contracted state, the edge of the crushing assembly 30 is within the range of the contact portion 3114. When the diameter of the weak geological layer decreases, the upward movement of the centralizer 20 is hindered, and the contact portion 3114 is used to contact the inner wall of the borehole after the diameter decreases. After moving to the diameter decrease position, the crushing assembly 30 switches from the contracted state to the expanded state, and the crushing assembly 30 is rotated by the drill rod and the connecting column 21 to expand the hole at the diameter decrease position.

[0053] The broken assembly 30 can be radially contracted or expanded. Optionally, a hydraulic rod can be arranged at the top of the centralizing unit 22 to push the broken assembly 30 to move along the radius direction to contract or expand. Alternatively, a battery can be arranged inside the centralizing unit 22 to drive the broken assembly 30 to radially expand or contract through an electric telescopic rod or a motor.

[0054] Please refer to Figures 2 to 7 , in order to facilitate the installation of the broken assembly 30, the top of the centralizing unit 22 is provided with an annular adjusting cavity around the connecting column 21, the sidewall of the liquid inlet channel 214 is provided with a liquid outlet hole 211 and a liquid inlet hole 212 respectively communicating with the adjusting cavity, the liquid outlet hole 211 is located above the liquid inlet hole 212, and the liquid inlet channel 214 is provided with a separation part 213 for separating the liquid inlet hole 212 and the liquid outlet hole 211. During normal drilling, the drilling fluid enters the liquid inlet channel 214 through the drill pipe and flows along the path shown by the arrow. The specific flow path is the liquid inlet channel 214, the liquid outlet hole 211, the adjusting cavity, the liquid inlet hole 212, the liquid inlet channel 214, the internal flow channel of the roller bit body 10, and the drilling fluid nozzle. Figure 3

[0055] The broken assembly 30 includes a hydraulic drive unit 31 and a plurality of broken units 32. The hydraulic drive unit 31 is arranged at the top of the centralizer 20, the lower part of the hydraulic drive unit 31 is in sliding fit with the adjusting cavity and has a pressure chamber 3111; the upper part of the hydraulic drive unit 31 has a contact part 3114 with the same diameter as the centralizer 20; the hydraulic drive unit 31 has an upper dead point and a lower dead point, when at the upper dead point, the pressure chamber 3111 is arranged above and below the liquid outlet hole 211 and the liquid inlet hole 212 respectively, when at the lower dead point, the pressure chamber 3111 is in communication with the liquid outlet hole 211 and is arranged above the liquid inlet hole 212; the plurality of broken units 32 are arranged above the contact part 3114 in a circumferential direction, and the hydraulic drive unit 31 is used to drive the plurality of broken units 32 to move along the radius direction of the contact part 3114.

[0056] The hydraulic drive unit 31 can move up and down, as shown in Figure 3 , during normal downward drilling or upward recovery of the drilling tool, the hydraulic drive unit 31 is at the upper dead point position, the pressure chamber 3111 of the hydraulic drive unit 31 is not in communication with the liquid outlet hole 211, no drilling fluid enters, and the hydraulic drive unit 31 does not work.

[0057] When moving to the reduced diameter position, the protruding hole wall pushes the hydraulic drive unit 31 to move downward due to the resistance of the upward lifting of the centralizing unit 22, so that the hydraulic drive unit 31 moves from the upper dead point to Figure 4 and Figure 5 ​The lower dead point position is shown. The pressure chamber 3111 communicates with the outlet hole 211, and the high-pressure drilling fluid enters the pressure chamber 3111 through the outlet hole 211, and the hydraulic drive unit 31 is driven to expand outward under the push of the high-pressure drilling fluid. The drill rod and the connecting column 21 rotate to drive the crushing unit 32 to crush the reduced diameter position of the inner wall of the borehole.

[0058] After the reaming is completed, the obstruction of the hydraulic drive unit 31 by the hole wall disappears, and the hydraulic drive unit 31 can be reset to the upper dead point by an external driving member (such as a hydraulic push rod, an electric push rod, etc.).

[0059] Alternatively, please refer to Figure 3 and Figure 7 , the hydraulic drive unit 31 includes a mounting seat 311, a piston 312 and a first elastic member 313. The mounting seat 311 is arranged at the top of the centralizer 20, the lower part of the mounting seat 311 is in sliding fit with the adjusting cavity, and the mounting seat 311 and the connecting column 21 together enclose the pressure chamber 3111, the upper part of the mounting seat 311 extends to the outside of the adjusting cavity and encloses the sliding cavity 3112 together with the connecting column 21, the mounting seat 311 has a flow hole 3113 communicating the adjusting cavity and the sliding cavity 3112, the side wall of the sliding cavity 3112 is provided with a plurality of installation grooves penetrating the wall thickness thereof in the circumferential direction, and a plurality of crushing units 32 are arranged in the installation grooves one by one.

[0060] The piston 312 is annular, and the piston 312 is in sliding fit in the sliding cavity 3112, the upper part of the piston 312 is a conical surface 3121, and the conical surface 3121 is in contact with the side of the crushing unit 32 extending to the sliding cavity 3112; the first elastic member 313 is arranged between the mounting seat 311 and the centralizing unit 22, and is configured to have a supporting force to keep the mounting seat 311 at the upper dead point position. The first elastic member 313 can be a spring or an elastic telescopic rod with a built-in spring. The mounting seat 311 and the piston 312 can move up and down, but cannot rotate.

[0061] As shown in Figure 7 , one end of the elastic telescopic rod is connected with the mounting seat 311, and the other end is connected with the centralizing unit 22. In order to make the stress uniform and the support more stable, a plurality of elastic telescopic rods can be arranged in the circumferential direction.

[0062] In order to improve the sealing performance, a sealing ring or a sealing ring can be arranged between the piston 312 and the inner wall of the sliding cavity 3112, and between the lower part of the mounting seat 311 and the adjusting cavity. The sealing ring and the sealing ring are both common sealing elements, and existing products on the market can be directly selected.

[0063] The mounting base 311 also has a contact portion 3114 for contacting the reduced diameter position of the hole wall, the contact portion 3114 and the top of the centralizing unit 22 correspond in shape and size, so that the contact portion 3114 is formed with a recess corresponding to the outlet of the debris passage 221 top, so as to facilitate the discharge of rock debris and drilling fluid. The connecting column 21 has a limiting ring 23 located at the upper stop position of the mounting base 311, for limiting the mounting base 311, preventing the mounting base 311 from continuing to move upward.

[0064] During the lifting process, the contact portion 3114 contacts the protruding hole wall, the contact portion 3114 overcomes the elastic force of the first elastic member 313, drives the entire mounting base 311 to move downward to the lower stop point, the high-pressure drilling fluid enters the pressure chamber 3111, and passes through the overflow hole 3113 into the sliding cavity 3112, drives the piston 312 to move upward, the conical surface 3121 of the piston 312 can push the plurality of crushing units 32 to expand outward until abutting against the inner wall of the borehole. The drill rod and the centralizer 20 drive the crushing unit 32 to rotate to ream the reduced diameter position. After the reaming is completed, under the support of the first elastic member 313, the hydraulic drive unit 31 is reset upward to the upper stop point, and the pressure chamber 3111 is no longer in communication with the outlet hole 211.

[0065] Please refer to Figure 3 、 Figure 5 and Figure 5 , the crushing unit 32 includes a crushing tooth 321 and a second elastic member 322, the crushing tooth 321 can be divided into a moving portion 3211 in sliding fit with the mounting groove, and a crushing portion 3212 facing the hole wall according to function, the moving portion 3211 has an inclined surface in contact with the conical surface 3121, the piston 312 moves upward, which can push the moving portion 3211 to expand outward through the conical surface 3121, so that the crushing portion 3212 abuts against the hole wall. The crushing portion 3212 is used for crushing the rock of the inner wall of the borehole. The second elastic member 322 is arranged between the moving portion 3211 and the mounting base 311, and is configured to have a pre-tightening force for moving the crushing tooth 321 to the central axis of the mounting base 311.

[0066] The crushing tooth 321 can be a common structure for rock crushing such as a roller and a PDC cutting tooth, which has the same material as the existing roller or PDC cutting tooth, high hardness and high wear resistance, and can crush rocks.

[0067] The second elastic member 322 can be a spring or other member capable of elastic expansion, when the mounting base 311 is reset from the lower stop point to the upper stop point, the piston 312 will fall under the action of gravity after the hydraulic pressure disappears, and the crushing tooth 321 will reset to the contracted state under the pre-tightening force of the second elastic member 322.

[0068] Please refer to Figure 1 and Figure 2 The side wall of the sliding cavity 3112 is provided with a plurality of pressure relief holes 3115 spaced along the circumference thereof, the pressure relief holes 3115 penetrating the wall thickness thereof, the pressure relief holes 3115 being located between two adjacent crushing teeth 321, the pressure relief holes 3115 being arranged at a position lower than the highest position to which the piston 312 can move, and specifically, the pressure relief holes 3115 being arranged at the lowermost position of the side wall of the sliding cavity 3112, so as to prevent the pressure relief holes 3115 from being blocked by the piston 312 and failing to smoothly release pressure.

[0069] Since the drilling fluid enters the sliding cavity 3112 from the flow holes 3113 and is discharged from the pressure relief holes 3115, in order to ensure that the piston 312 is lifted by the sufficient pressure in the sliding cavity 3112, the diameter of the pressure relief holes 3115 should not be too large. Specifically, the sum of the cross-sectional areas of the plurality of pressure relief holes 3115 should be less than or equal to the sum of the cross-sectional areas of the plurality of flow holes 3113.

[0070] The arrangement of the pressure relief holes 3115 can not only discharge the drilling fluid remaining in the sliding cavity 3112 after the reaming is completed, but also, since the pressure relief holes 3115 are located between two adjacent crushing teeth 321, when the reaming unit 32 reams the hole wall, the drilling fluid will be sprayed from the pressure relief holes 3115, carrying away the rock debris generated by crushing, thereby playing a role of chip removal.

[0071] Please refer to Figure 2 Since the adjusting cavity, the pressure chamber 3111 and the sliding cavity 3112 are annular, the corresponding liquid inlet holes 212, liquid outlet holes 211 and flow holes 3113 can be provided with a plurality of holes spaced along the circumference of the connecting column 21, so that the drilling fluid flows more uniformly and quickly.

[0072] Please refer to Figure 1 The outer circumferential surface of the stabilizing unit 22 is provided with a spiral-shaped chip removal channel 221, the chip removal channel 221 penetrating the stabilizing unit 22 from top to bottom, and the lower end of the chip removal channel 221 is in one-to-one correspondence with the chip removal groove 11 of the roller bit body 10, so that the chip removal is smooth. When a three-cone bit body is used, three chip removal channels 221 are provided.

[0073] Please refer to Figure 1 The surface between two adjacent chip removal channels 221 is defined as a gage protection portion 222, the outer surface of the gage protection portion 222 is provided with a plurality of gage protection teeth 223, and the plurality of gage protection teeth 223 are uniformly arranged on the outer surface of the gage protection portion 222. The gage protection teeth 223 can continuously cut and clean the hole wall when the stabilizing unit 22 rotates, thereby ensuring the consistency of the size and specification of the hole.

[0074] The shape, structure and arrangement of the gage protection teeth 223 are not specifically limited, and the user can arrange them as needed.

[0075] It can be understood that the parts in the above embodiments can be freely combined or deleted to form different combined embodiments, and the specific content of each combined embodiment will not be described here. After the description, it can be considered that the present application has described each combined embodiment and can support different combined embodiments.

[0076] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high-efficiency rock-breaking roller cone drill bit, characterized in that, The application relates to a drilling device, which comprises the following parts: a roller drill body (10); a centralizer (20) comprising a connecting column (21) and a centralizing unit (22), the lower end of the connecting column (21) being detachably connected with the upper end of the roller drill body (10), the inside of the connecting column (21) being formed with a liquid inlet channel (214) which is communicated with the internal flow channel of the roller drill, and the centralizing unit (22) being coaxially arranged on the outer periphery of the connecting column (21); and a crushing assembly (30) arranged on the top of the centralizing unit (22), the crushing diameter of the crushing assembly (30) being greater than or equal to the drilling diameter of the roller drill body (10).

2. The roller cone bit for high efficiency rock breaking of claim 1, wherein, An annular adjusting cavity is formed on the top of the centralizing unit (22) around the connecting column (21), the side wall of the liquid inlet channel (214) is formed with a liquid outlet hole (211) and a liquid inlet hole (212) which are respectively communicated with the adjusting cavity, the liquid outlet hole (211) is located above the liquid inlet hole (212), and a separation part (213) is arranged in the liquid inlet channel (214) for separating the liquid inlet hole (212) and the liquid outlet hole (211). The crushing assembly (30) comprises a hydraulic drive unit (31) and a plurality of crushing units (32), the hydraulic drive unit (31) is arranged on the top of the centralizing unit (22), the lower part of the hydraulic drive unit (31) is slidably matched with the adjusting cavity and is provided with a pressure chamber (3111), the upper part of the hydraulic drive unit (31) is provided with a contact part (3114) which has the same diameter as the centralizing unit (22), the hydraulic drive unit (31) is provided with an upper dead point and a lower dead point, when being at the upper dead point, the pressure chamber (3111) is arranged in a staggered mode with the liquid outlet hole (211) and the liquid inlet hole (212) in sequence, when being at the lower dead point, the pressure chamber (3111) is communicated with the liquid outlet hole (211) and is arranged in a staggered mode with the liquid inlet hole (212), a plurality of the crushing units (32) are arranged above the contact part (3114) in a circumferential interval, and the hydraulic drive unit (31) is used for driving the plurality of crushing units (32) to move along the radial direction of the contact part (3114).

3. The roller cone bit of claim 2, wherein, The hydraulic drive unit (31) comprises: a mounting base (311) arranged on the top of the centralizer (20), the lower part of the mounting base (311) is slidably matched with the adjusting cavity and jointly encloses the pressure chamber (3111) with the connecting column (21), the upper part of the mounting base (311) extends to the outside of the adjusting cavity and jointly encloses a sliding cavity (3112) with the connecting column (21), the mounting base (311) is provided with an overflow hole (3113) which is communicated with the adjusting cavity and the sliding cavity (3112), the side wall of the sliding cavity (3112) is formed with a plurality of mounting grooves which penetrate the wall thickness, and a plurality of the crushing units (32) are arranged in the mounting grooves in a one-to-one correspondence, and the mounting base (311) is provided with the contact part (3114). A piston (312) is slidingly fitted in the sliding cavity (3112), an upper portion of the piston (312) is a tapered surface (3121) and is in contact with one side of the breaking unit (32) extending to the sliding cavity (3112); and A first elastic member (313) is arranged between the mounting seat (311) and the centralizing unit (22) and is configured to have a supporting force to keep the mounting seat (311) at a top dead center position.

4. The roller cone bit of claim 3, wherein, The breaking unit (32) comprises: A breaking tooth (321) has a moving portion (3211) slidingly fitted in the mounting groove and a breaking portion (3212) facing a borehole wall, the moving portion (3211) is in contact with the tapered surface (3121); and A second elastic member (322) is arranged between the moving portion (3211) and the mounting seat (311) and is configured to have a pre-tightening force to move the breaking tooth (321) to a central axis of the mounting seat (311).

5. The roller cone bit of claim 4, wherein, A plurality of pressure relief holes (3115) are arranged along a circumferential direction of a side wall of the sliding cavity (3112), the pressure relief holes (3115) penetrate a wall thickness of the side wall, the pressure relief holes (3115) are located between adjacent two breaking teeth (321), and the pressure relief holes (3115) are lower than a highest position at which the piston (312) can move.

6. The roller cone bit of claim 4, wherein, The breaking tooth (321) is one of a roller bit and a PDC cutting tooth.

7. The roller cone bit of claim 3, wherein, The first elastic member (313) is an elastic telescopic rod, one end of the elastic telescopic rod is connected with the mounting seat (311), and the other end of the elastic telescopic rod is connected with the centralizing unit (22).

8. The roller cone bit of claim 3, wherein, The liquid inlet hole (212), the liquid outlet hole (211) and the overflow hole (3113) are each arranged with a plurality of holes along a circumferential direction of the connecting column (21).

9. The roller cone bit of claim 1, wherein, An outer circumferential surface of the centralizing unit (22) is provided with a spiral-shaped chip removal channel (221), the chip removal channel (221) penetrates the centralizing unit (22) from top to bottom, and a lower end of the chip removal channel (221) is in one-to-one correspondence with the chip removal groove (11) of the roller bit body (10).

10. The roller cone bit of claim 9, wherein, A face between adjacent two chip removal channels (221) is defined as a gauge protection portion (222), and an outer surface of the gauge protection portion (222) is provided with a gauge protection tooth (223).

Images