Drill bit protection device

Abstract

The invention relates to the technical field of drill bit protection devices, and is a drill bit protection device; the drill bit protection device comprises a lower connecting core shaft, an upper connecting outer cylinder assembly and an elastic component; an elastic component is fixedly installed between the upper outer side of the lower connecting core shaft and the lower inner side of the upper connecting outer cylinder assembly, which can be twisted and moved upward when the lower connecting core shaft is subjected to a blocking resistance, and can be restored to its original state after the blocking resistance disappears; the invention has a reasonable and compact structure and is easy to use; when the drill bit is stuck, the drill collar continues to output torque and acts on the elastic rod, and the elastic rod twists and moves upward around the lower connecting core shaft, driving the lower connecting core shaft and the drill bit to withdraw the drill upward, while the penetration depth of the drill bit into the stuck formation is gradually reduced, and the torsion of the elastic component will also generate additional torque to increase the cutting force of the drill bit, so that the drill bit can overcome the blocking resistance to achieve formation cutting, avoid drill bit tooth breakage, drill jumping, and premature damage of the drill bit, maintain stable cutting of the drill bit, and improve the mechanical drilling speed.

Description

Technical Field

[0001] The invention relates to the technical field of drill bit protection devices and relates to a drill bit protection device. Background Art

[0002] During the drilling process, due to the heterogeneity of the formation, the depth of the drill bit entering the formation is constantly changing, and the drill bit is stuck during cutting, resulting in drill tooth breakage and drill bit jump, causing premature damage to the drill bit, shortening the drill bit life, and reducing the mechanical drilling speed. Summary of the invention

[0003] The present invention provides a drill bit protection device, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problem of the drill bit being blocked during cutting and causing damage to the drill bit.

[0004] The technical solution of the present invention is achieved through the following measures: a drill bit protection device, including a lower connecting core shaft, an upper connecting outer cylinder assembly and an elastic component; an elastic component is fixedly installed between the upper outer side of the lower connecting core shaft and the lower inner side of the upper connecting outer cylinder assembly, which can be twisted and moved upward when the lower connecting core shaft is subjected to a blocking resistance, and return to its original state after the blocking resistance disappears.

[0005] The following are further optimizations and / or improvements to the above technical solutions:

[0006] The elastic component comprises an elastic rod, a lower limit fastener and an upper limit fastener; the elastic rod is an elastic rod made of elastic material, an elastic member mounting ring is arranged on the lower outer part of the lower connecting core shaft, the lower side of the upper connecting outer cylinder assembly is sleeved on the outer side of the elastic member mounting ring, an annular cavity is formed between the upper connecting outer cylinder assembly and the lower connecting core shaft on the upper side of the elastic member mounting ring, at least two elastic rods circumferentially wound around the outer side of the lower connecting core shaft and having the same rotation direction are fixedly installed in the annular cavity, and elastic members circumferentially distributed on the upper outer side of the elastic member mounting ring are arranged on the upper side of the elastic member mounting ring. The lower end of the elastic rod corresponds to the limit lower groove, and the lower end of the elastic rod is fixed with a vertical lower plug rod, which is fixedly installed in the corresponding limit lower groove through a lower limit fastener; a limit sleeve is fixedly installed in the upper connecting outer cylinder assembly on the upper side of the annular cavity, and the limit sleeve is sleeved on the lower connecting core shaft; the limit upper groove corresponding to the upper end of the elastic rod is distributed circumferentially in the limit sleeve, and the upper end of the elastic rod is fixed with a vertical upper plug rod, which is fixedly installed in the corresponding limit upper groove through an upper limit fastener.

[0007] The above-mentioned upper connecting outer cylinder assembly includes an outer cylinder 7, a conversion joint 8 and an upper joint 9; the upper inner side of the outer cylinder 7 is fixedly installed with the lower outer side of the conversion joint 8; the upper outer side of the conversion joint 8 is fixedly installed with the lower inner side of the upper joint 9; the lower connecting core shaft is a three-step shaft that is narrow at the top and wide at the bottom, and from top to bottom are respectively a first-step shaft section 10, a second-step shaft section 11 and a third-step shaft section 12; the elastic member mounting ring 2 is located outside the lower part of the second-step shaft section 11; the inner end sealing sleeve of the conversion joint 8 is outside the upper part of the second-step shaft section 11; the lower end of the conversion joint 8 is respectively connected to the outer cylinder 7, the middle part of the second-step shaft section 11, and the upper end of the elastic member mounting ring 2 An annular cavity 3 is formed, and a limit sleeve mounting groove is provided in the outer cylinder 7 at the upper part of the annular cavity 3, and the limit sleeve 5 is seated in the limit sleeve mounting groove and is fixedly connected with the conversion joint 8; an inner sealing ring platform 13 is provided in the middle part of the upper joint 9, and the inner sealing ring platform 13 is sealingly sleeved outside the first-order shaft section 10, and a spring mounting groove 14 is provided in the lower part of the upper joint 9 between the lower end of the inner sealing ring platform 13 and the upper end of the second-order shaft section 11, and a thrust elastic member 15 is installed in the spring mounting groove 14, and the upper end of the thrust elastic member 15 is pressed against the inner sealing ring platform 13, and the lower end of the thrust elastic member 15 is pressed against the upper ends of the second-order shaft section 11 and the conversion joint 8.

[0008] A suspension joint is fixedly installed on the first-stage shaft section at the upper end of the inner sealing ring platform; or / and, a tapered thread with a wider top and a narrower bottom is provided on the upper side of the upper joint; a tapered thread with a narrower top and a wider bottom is provided on the lower side of the third-stage shaft section.

[0009] The upper end of the limiting sleeve outside the above-mentioned limiting upper slot is provided with at least two limiting collar claw pieces distributed at circumferential intervals, and a socket opening facing upward is formed between adjacent limiting collar claw pieces; the lower end of the conversion joint corresponding to the socket is provided with a connector claw piece, which is inserted into the socket and engages with the limiting collar claw piece; a horizontal corresponding ring opening is provided outside each limiting collar claw piece, and an elastic open retaining ring is fixedly installed in the ring opening, which can tighten and fix the connector claw piece and the limiting collar claw piece inward, and the outer ring surface of the elastic open retaining ring is against the outer tube.

[0010] The above-mentioned upper limit fastener is an upper fastening nut; an upper limit clamping platform is provided in the lower part of the upper limit slot, and an upper fastening nut is fixedly installed on the outer side of the upper insertion rod at the upper end of the upper limit clamping platform through threads, and the lower end of the upper fastening nut abuts against the upper limit clamping platform and limits the axial position of the upper insertion rod in the upper limit slot.

[0011] An upper anti-loosening nut is fixedly installed on the outer side of the upper insertion rod at the upper end of the upper fastening nut through threads.

[0012] The above-mentioned lower limit fastener is a lower fastening nut. A lower limit clamping platform is provided on the second-order shaft section in the upper part of the lower limit clamping groove. A stop sleeve is mounted on the lower insertion rod at the lower end of the lower limit clamping platform. A lower fastening nut is fixedly installed on the outside of the lower insertion rod at the lower end of the stop sleeve through threads. The upper end of the lower fastening nut is pressed against the stop sleeve and limits the axial position of the lower insertion rod in the lower limit clamping groove.

[0013] A lower anti-loosening nut is fixedly installed on the outside of the lower insertion rod at the lower end of the lower fastening nut through threads.

[0014] The upper side of the outer cylinder is provided with threads inside, and is fixedly installed with the conversion joint through threads; or / and, the upper side of the conversion joint is provided with threads outside, and is fixedly installed with the upper joint through threads; or / and, the upper side of the first-order shaft section is provided with threads outside, and is fixedly installed with the suspension joint through threads.

[0015] A sealing ring is fixedly installed between the inner sealing ring platform and the first-stage shaft section; at least one sealing ring is fixedly installed between the conversion joint on the upper side of the ring cavity and the second-stage shaft section; and a sealing ring is fixedly installed between the conversion joint on the upper side of the ring cavity and the outer tube.

[0016] The invention has a reasonable and compact structure and is easy to use. When the drill bit is stuck, the drill collar continues to output torque and acts on the elastic rod, and the elastic rod twists and moves upward around the lower connecting core shaft, driving the lower connecting core shaft and the drill bit to withdraw the drill upward. While the penetration depth of the drill bit into the stuck formation is gradually reduced, the twisting of the elastic component will also generate additional torque to increase the cutting force of the drill bit, so that the drill bit can overcome the jamming and realize formation cutting, avoid drill bit tooth breakage, drill jumping, and premature damage of the drill bit, maintain stable cutting of the drill bit, and improve the mechanical drilling speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attached Figure 1 It is a schematic diagram of the main half-section structure of the upper half of the best embodiment of the present invention.

[0018] Attached Figure 2 For attachment Figure 1 The enlarged structural diagram at point Ⅰ is shown in the figure.

[0019] Attached Figure 3 For attachment Figure 1 Enlarged structural diagram at point II in the middle.

[0020] Attached Figure 4 For attachment Figure 1 Schematic diagram of the enlarged structure viewed along the AA axis.

[0021] Attached Figure 5 For attachment Figure 1 Schematic diagram of the enlarged structure in the BB section.

[0022] Attached Figure 6 For attachment Figure 1 Schematic diagram of the enlarged structure in the CC section.

[0023] Attached Figure 7 For attachment Figure 1 Schematic diagram of the enlarged structure in the DD section.

[0024] Attached Figure 8It is a schematic diagram of the main half-section structure of the lower half of the best embodiment of the present invention.

[0025] The codes in the accompanying drawings are: 1 is an elastic rod, 2 is an elastic member mounting ring, 3 is a ring cavity, 4 is a lower plug rod, 5 is a limit sleeve, 6 is an upper plug rod, 7 is an outer cylinder, 8 is a conversion joint, 9 is an upper joint, 10 is a first-order shaft section, 11 is a second-order shaft section, 12 is a third-order shaft section, 13 is an inner sealing ring platform, 14 is a spring mounting groove, 15 is a thrust elastic member, 16 is a suspension joint, 17 is a joint claw piece, 18 is a limit sleeve claw piece, 19 is an elastic open retaining ring, 20 is an upper fastening nut, 21 is an upper limit clamping platform, 22 is an upper anti-loosening nut, 23 is a lower fastening nut, 24 is a lower anti-loosening nut, 25 is a sealing ring, 26 is a retaining sleeve, 27 is a limit upper clamping groove, 28 is a limit lower clamping groove, and 29 is a lower limit clamping platform. DETAILED DESCRIPTION

[0026] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0027] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The layout is described in detail, such as the positional relationship of top, bottom, left, right, etc. is based on the instructions attached to the manual. Figure 1 The layout direction is determined by the

[0028] The present invention will be further described below in conjunction with embodiments and drawings:

[0029] As attached Figure 1 and 8 As shown, the drill bit protection device includes a lower connecting core shaft, an upper connecting outer cylinder assembly and an elastic component; an elastic component is fixedly installed between the upper outer side of the lower connecting core shaft and the lower inner side of the upper connecting outer cylinder assembly, which can be twisted upward when the lower connecting core shaft is subjected to a blocking resistance, and return to its original state after the blocking resistance disappears.

[0030] Wherein, the elastic component is a torsional elastic component; the minimum deformation value of the elastic component is less than or equal to the maximum cutting force of the drill bit and greater than the minimum cutting force of the drill bit;

[0031] During the drilling process, the drill bit protection device is installed between the drill collar and the drill bit; the upper end of the upper connecting outer cylinder assembly is installed with the drill collar, and the lower end of the lower connecting mandrel is installed with the drill bit; the drill collar outputs a rotational torque, which drives the drill bit to rotate through the upper connecting outer cylinder assembly, the elastic component and the lower connecting mandrel in sequence; when the drill bit torque exceeds the set cutting value (the minimum deformation value of the elastic component), it encounters a jam, at which time the drill collar continues to output torque and acts on the elastic component, the elastic component twists and moves upward, driving the lower connecting mandrel and the drill bit to withdraw the drill upward, and as the drill bit As the drill bit moves upward gradually, the penetration depth of the drill bit into the stuck formation gradually decreases, and the sticking resistance of the stuck formation underground will also gradually decrease; at the same time, the torsion of the elastic component will also generate additional torque, further increasing the cutting force of the drill bit. When the drill bit torque is less than the set cutting value, that is, within the rated cutting range, the drill bit can completely overcome the sticking resistance and realize formation cutting, thereby solving the problem of drill bit sticking, avoiding drill bit tooth breakage, drill jumping, and premature damage of the drill bit, maintaining stable cutting of the drill bit, and improving the mechanical drilling speed.

[0032] The drill bit protection device can be further optimized and / or improved according to actual needs:

[0033] As attached Figure 2 , 4 As shown in Figures 5, 6, 7 and 8, the elastic component includes an elastic rod 1, a lower limit fastener and an upper limit fastener; the elastic rod 1 is an elastic rod made of elastic material, an elastic member mounting ring 2 is arranged on the lower outer part of the lower connecting core shaft, the lower side of the upper connecting outer cylinder assembly is sleeved on the outside of the elastic member mounting ring 2, an annular cavity 3 is formed between the upper connecting outer cylinder assembly and the lower connecting core shaft on the upper side of the elastic member mounting ring 2, at least two elastic rods 1 circumferentially wound around the outer side of the lower connecting core shaft and having the same rotation direction are fixedly installed in the annular cavity 3, and elastic members 1 circumferentially arranged on the upper outer part of the elastic member mounting ring 2 are distributed circumferentially with the elastic member. The lower end of the rod 1 corresponds to the limit lower groove 28, and the lower end of the elastic rod 1 is fixed with a vertical lower plug rod 4, which is fixedly installed in the corresponding limit lower groove 28 through a lower limit fastener; a limit sleeve 5 is fixedly installed in the upper connecting outer cylinder assembly on the upper side of the annular cavity 3, and the limit sleeve 5 is sleeved on the lower connecting core shaft; the limit upper groove 27 corresponding to the upper end of the elastic rod 1 is distributed circumferentially in the limit sleeve 5, and the upper end of the elastic rod 1 is fixed with a vertical upper plug rod 6, which is fixedly installed in the corresponding limit upper groove 27 through an upper limit fastener. Among them, the elastic rod 1 circumferentially wound around the lower connecting core shaft forms a structure that can withstand torsional force and is similar to a "claw spring". When the upper connecting outer cylinder assembly is subjected to a rotational torque and the lower connecting core shaft is stuck, the upper connecting outer cylinder assembly applies a rotational torque to the elastic rod 1, and the elastic rod 1 is subjected to a rotational torque and undergoes circumferential torsional deformation, and drives the lower connecting core shaft to rotate and move upward to achieve drill withdrawal; the rotation angle and number of the elastic rod 1 are determined according to the maximum cutting force and the minimum cutting force under actual working conditions.

[0034] As attached Figure 1 , 2 , 4, 5, and 8, the upper connecting outer cylinder assembly includes an outer cylinder 7, a conversion joint 8, and an upper joint 9; the upper inner side of the outer cylinder 7 is fixedly installed with the lower outer side of the conversion joint 8; the upper outer side of the conversion joint 8 is fixedly installed with the lower inner side of the upper joint 9; the lower connecting core shaft is a three-step shaft that is narrow at the top and wide at the bottom, and from top to bottom are respectively a first-step shaft section 10, a second-step shaft section 11, and a third-step shaft section 12; the elastic member mounting ring 2 is located outside the lower part of the second-step shaft section 11; the inner end sealing sleeve of the conversion joint 8 is mounted outside the upper part of the second-step shaft section 11; the lower end of the conversion joint 8 is respectively connected to the outer cylinder 7, the middle part of the second-step shaft section 11, and the elastic member mounting ring 2 An annular cavity 3 is formed between the upper ends, and a limit sleeve mounting groove is provided in the outer cylinder 7 at the upper part of the annular cavity 3. The limit sleeve 5 is seated in the limit sleeve mounting groove and is fixedly connected with the conversion joint 8; an inner sealing ring platform 13 is provided in the middle part of the upper joint 9, and the inner sealing ring platform 13 sealing sleeve is installed outside the first-order shaft section 10. A spring mounting groove 14 is provided in the lower part of the upper joint 9 between the lower end of the inner sealing ring platform 13 and the upper end of the second-order shaft section 11, and a thrust elastic member 15 is installed in the spring mounting groove 14. The upper end of the thrust elastic member 15 is pressed against the inner sealing ring platform 13, and the lower end of the thrust elastic member 15 is pressed against the upper ends of the second-order shaft section 11 and the conversion joint 8. Among them, the conversion joint 8 is used to connect the upper joint 9 and the outer tube 7; the upper joint 9 is used to connect the drill collar; the added thrust elastic member 15 plays a role in assisting the resetting of the elastic component; when the drill bit and the lower connecting core shaft are rotated and moved upward by the action of the elastic component, the upper end of the lower connecting core shaft compresses the thrust elastic member 15; since the drill collar driving torque that causes the elastic component to torsionally deform is very large, even if there is resistance from the thrust elastic member 15, it can be ignored; and when the jamming disappears, the drill collar driving torque acts on the drill bit cutting, and the resetting force of the thrust elastic member 15 pushes the lower connecting core shaft downward to reset, so as to further ensure that the elastic component can be completely reset.

[0035] To facilitate lifting, Figure 1 As shown, a suspension joint 16 is fixedly installed outside the first-stage shaft section 10 at the upper end of the inner sealing ring platform 13; or / and, in order to facilitate the connection of the drill bit protection device with the drill collar and the drill bit respectively, as shown in the attached Figure 1 As shown, a tapered thread which is wider at the top and narrower at the bottom is provided on the upper side of the upper joint 9; a tapered thread which is narrower at the top and wider at the bottom is provided on the lower side of the third-step shaft section 12.

[0036] As attached Figure 2 , 3As shown in Figures 8 and 9, at least two limiting collar claws 18 are arranged at intervals on the upper end of the limiting sleeve 5 outside the limiting upper slot 27, and a socket with an opening upward is formed between adjacent limiting collar claws 18; a connector claw 17 is arranged at the lower end of the conversion joint 8 corresponding to the socket, and the connector claw 17 is inserted into the socket and interlocked with the limiting collar claw 18; a horizontal corresponding ring is arranged outside each limiting collar claw 18, and an elastic open retaining ring 19 is fixedly installed in the ring to tighten and fix the connector claw 17 and the limiting collar claw 18 inwardly, and the outer ring surface of the elastic open retaining ring 19 is against the outer tube 7. Among them, the elastic open retaining ring 19 not only holds the mutually interlocking connector claw 17 and the limiting collar claw 18 tightly, but also forms an axial limiting relationship among the conversion joint 8, the limiting sleeve 5 and the outer tube 7. The connection structure is simple, no other auxiliary fastening elements are required, and no extra space is occupied, so that the drill bit protection device structure is more compact.

[0037] To facilitate disassembly and assembly, Figure 2 , 4 As shown in Figures 5 and 8, the upper limit fastener is an upper fastening nut 20; an upper limit clamping platform 21 is provided in the lower part of the upper limit slot 27, and the upper insertion rod 6 at the upper end of the upper limit clamping platform 21 is fixed with the upper fastening nut 20 by threads, and the lower end of the upper fastening nut 20 rests on the upper limit clamping platform 21 and limits the axial position of the upper insertion rod 6 in the upper limit slot 27.

[0038] As attached Figure 2 , 8 As shown, an upper locking nut 22 is fixedly installed by threading outside the upper insertion rod 6 at the upper end of the upper fastening nut 20. Like this, the upper locking nut 22 forms a double nut structure with the upper fastening nut 20, further increasing the effect of anti-loosening and fastening.

[0039] To facilitate disassembly and assembly, Figure 3 , 6 As shown in , 7 and 8, the lower limit fastener is a lower fastening nut 23, and a lower limit clamping platform 29 is provided on the second-stage shaft section 11 in the upper part of the lower limit clamping groove 28. A stop sleeve 26 is sleeved on the lower insertion rod 4 at the lower end of the lower limit clamping platform 29, and the lower fastening nut 23 is fixedly installed on the outside of the lower insertion rod 4 at the lower end of the stop sleeve 26 by threads. The upper end of the lower fastening nut 23 is pressed against the stop sleeve 26 and axially limits the lower insertion rod 4 in the lower limit clamping groove 28.

[0040] As attached Figure 3 , 8 As shown, a lower anti-loosening nut 24 is installed outside the lower plunger 4 at the lower end of the lower fastening nut 23 by threaded fixing. Like this, the lower anti-loosening nut 24 and the lower fastening nut 23 form a double nut structure, further increasing the anti-loosening and fastening effect.

[0041] To facilitate disassembly and assembly, Figure 1 ,8 As shown, the upper side of the outer cylinder 7 is provided with threads inside, and is fixedly installed with the conversion joint 8 through threads; or / and, the upper side of the conversion joint 8 is provided with threads outside, and is fixedly installed with the upper joint 9 through threads; or / and, the upper side of the first-order shaft section 10 is provided with threads outside, and is fixedly installed with the suspension joint 16 through threads.

[0042] To increase the sealing effect, Figure 1 , 8 As shown, a sealing ring 25 is fixedly installed between the inner sealing ring 13 and the first-stage shaft section 10; at least one sealing ring 25 is fixedly installed between the conversion joint 8 on the upper side of the annular cavity 3 and the second-stage shaft section 11; and a sealing ring 25 is fixedly installed between the conversion joint 8 on the upper side of the annular cavity 3 and the outer tube 7.

[0043] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A drill bit protection device, characterized in that The invention comprises a lower connecting core shaft, an upper connecting outer cylinder assembly and an elastic component; an elastic component is fixedly installed between the upper outer side of the lower connecting core shaft and the lower inner side of the upper connecting outer cylinder assembly, which can be twisted and moved upward when the lower connecting core shaft is subjected to a blocking resistance, and restore the original state after the blocking resistance disappears, and the elastic component comprises an elastic rod, a lower limit fastener and an upper limit fastener; the elastic rod is an elastic rod made of elastic material, an elastic component mounting ring is arranged on the lower outer side of the lower connecting core shaft, the lower side of the upper connecting outer cylinder assembly is sleeved on the outside of the elastic component mounting ring, and an annular cavity is formed between the upper connecting outer cylinder assembly and the lower connecting core shaft on the upper side of the elastic component mounting ring, and at least two elastic rods circumferentially wound around the outer side of the lower connecting core shaft and having the same rotation direction are fixedly installed in the annular cavity, and circumferentially distributed on the outer side of the upper part of the elastic component mounting ring are elastic components that are similar to the elastic rods. The lower end corresponds to the limit lower groove, and the lower end of the elastic rod is fixed with a vertical lower plug rod, and the lower plug rod is fixedly installed in the corresponding limit lower groove through the lower limit fastener; a limit sleeve is fixedly installed in the upper connecting outer cylinder assembly on the upper side of the annular cavity, and the limit sleeve is sleeved on the lower connecting core shaft; the limit upper groove corresponding to the upper end of the elastic rod is distributed circumferentially in the limit sleeve, and the upper end of the elastic rod is fixed with a vertical upper plug rod, and the upper plug rod is fixedly installed in the corresponding limit upper groove through the upper limit fastener, and the upper connecting outer cylinder assembly includes an outer cylinder, a conversion joint and an upper joint; the upper inner side of the outer cylinder is fixedly installed with the lower outer side of the conversion joint; the upper outer side of the conversion joint is fixedly installed with the lower inner side of the upper joint; the lower connecting core shaft is a three-order shaft with a narrow upper and a wide lower side, which is respectively from top to bottom. The first-order shaft section, the second-order shaft section and the third-order shaft section; the elastic member mounting ring is located outside the lower part of the second-order shaft section; the inner end sealing sleeve of the conversion joint is mounted outside the upper part of the second-order shaft section; the lower end of the conversion joint forms an annular cavity with the outer cylinder, the middle part of the second-order shaft section and the upper end of the elastic member mounting ring respectively, and a limit sleeve mounting groove is provided in the outer cylinder at the upper part of the annular cavity, and the limit sleeve sits in the limit sleeve mounting groove and is fixedly connected with the conversion joint; an inner sealing ring platform is provided in the middle part of the upper joint, and the inner sealing ring platform sealing sleeve is mounted outside the first-order shaft section, and a spring mounting groove is provided in the lower part of the upper joint between the lower end of the inner sealing ring platform and the upper end of the second-order shaft section, and a thrust elastic member is installed in the spring mounting groove, and the upper end of the thrust elastic member is pressed against the inner sealing ring platform, and the lower end of the thrust elastic member is pressed against the upper end of the second-order shaft section and the conversion joint, and the inner sealing A suspension joint is fixedly installed outside the first-order shaft section at the upper end of the ring platform; or / and, a tapered thread which is wide at the top and narrow at the bottom is provided inside the upper side of the upper joint; a tapered thread which is narrow at the top and wide at the bottom is provided inside the lower side of the third-order shaft section, and at least two limit collar claw pieces distributed at circumferential intervals are provided at the upper end of the limit sleeve outside the upper limit slot, and a socket opening facing upward is formed between adjacent limit collar claw pieces; a connector claw piece is provided at the lower end of the conversion joint corresponding to the socket, and the connector claw piece is inserted into the socket and engages with the limit collar claw piece; a horizontal corresponding ring opening is provided outside each limit collar claw piece, and an elastic open retaining ring which can tighten and fix the connector claw piece and the limit collar claw piece inward is fixedly installed in the ring opening, and the outer ring surface of the elastic open retaining ring is against the outer cylinder, and a thread is provided inside the upper side of the outer cylinder, and the elastic open retaining ring is fixedly installed together with the conversion joint through the thread;Or / and, the upper side of the conversion joint is provided with a thread, and is fixedly installed with the upper joint through the thread; or / and, the upper side of the first-order shaft section is provided with a thread, and is fixedly installed with the suspension joint through the thread, and the upper limit fastener is an upper fastening nut; an upper limit clamping platform is provided in the lower part of the upper limit slot, and an upper fastening nut is fixedly installed on the upper plug rod at the upper end of the upper limit clamping platform through a thread, and the lower end of the upper fastening nut abuts against the upper limit clamping platform and limits the axial position of the upper plug rod in the upper limit slot, and the upper The upper plug rod at the upper end of the fastening nut is fixedly installed with an upper anti-loosening nut through threads; or / and, the lower limit fastener is a lower fastening nut, a lower limit clamping platform is provided on the second-order shaft section in the upper part of the limit lower clamping slot, a stopper sleeve is sleeved on the lower plug rod at the lower end of the lower limit clamping platform, and a lower fastening nut is fixedly installed with threads on the lower plug rod at the lower end of the stopper sleeve, the upper end of the lower fastening nut is pressed against the stopper sleeve and the lower plug rod is axially limited in the limit lower clamping slot, and a lower anti-loosening nut is fixedly installed with threads on the lower plug rod at the lower end of the lower fastening nut. ; 2. The drill bit protection device according to claim 1, characterized in that A sealing ring is fixedly installed between the inner sealing ring platform and the first-stage shaft section; at least one sealing ring is fixedly installed between the conversion joint on the upper side of the ring cavity and the second-stage shaft section; and a sealing ring is fixedly installed between the conversion joint on the upper side of the ring cavity and the outer tube.

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