Self-drilling type hollow anchor rod drill bit

Abstract

The self-drilling type hollow anchor rod drill bit comprises a drill bit body, a cross-shaped blade is arranged on the drill bit body, a connecting hole is formed in the lower side of the drill bit body, a threaded connecting part is arranged on the inner wall of the connecting hole, and a transition cavity is formed in the upper side of the connecting hole. The invention relates to the technical field of anchor rod drill bits, two pairs of trumpet-shaped water outlet holes are additionally formed in a drill bit body, the purpose of increasing the water removal pressure is achieved by changing the diameters of the water outlet ends of the water outlet holes, meanwhile, the water outlet amount can be guaranteed, the chip removal effect is improved, a pair of air inlet holes is additionally formed, and the pressure intensity of the water outlet holes and the chip removal effect are further improved. And the first inclined block and the second inclined block are additionally arranged, so that the conditions of energy loss and pressure reduction at the joint of fluid in the anchor rod and the drill bit are reduced.

Description

Technical Field

[0001] This invention relates to the field of anchor drill bit technology, specifically a self-drilling hollow anchor drill bit. Background Technology

[0002] Self-drilling anchors are a type of anchoring support device that integrates drilling, grouting, and anchoring functions. They are mainly used in tunnel pre-support, slope treatment, and rock mass reinforcement projects under complex geological conditions such as high ground stress and large deformation. Through integrated design, they solve the technical problems of traditional anchors being prone to hole collapse or being unable to construct long anchors in weak surrounding rock and fractured strata.

[0003] CN104110219B discloses a self-drilling hollow anchor drill bit, including a cross-shaped cutting edge, a drill bit skirt, four symmetrical upper slag discharge grooves, four symmetrical lower slag discharge grooves, internal threads, a transition blind hole, and two water inlets. This self-drilling hollow anchor drill bit has two lower air inlets, which are through holes. By replacing two of the four water inlets in the slag discharge grooves with lower air inlets, when water or air enters the water inlets from the transition blind hole, the reduced cross-sectional area and increased velocity create a low pressure at the inlet of the water inlet, drawing air from the lower air inlets inward. This increases the pressure at which water or air exits the water inlet, thereby achieving the purpose of cleaning the borehole.

[0004] This self-drilling hollow anchor drill bit reduces the number of water inlets by replacing two of the four water inlets with lower air inlets, thus increasing the drainage pressure at the water inlets. However, this reduces the amount of water output from the drill bit and still affects the overall chip removal of the hollow anchor. Summary of the Invention

[0005] The present invention aims to provide a self-drilling hollow anchor drill bit that can clean the drill hole without affecting the smooth chip removal process, thereby improving the drilling efficiency.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a self-drilling hollow anchor drill bit, comprising a drill bit body, a cross blade provided on the drill bit body, a connecting hole provided on the lower side of the drill bit body, a threaded connection part provided on the inner wall of the connecting hole, and a transition cavity provided on the upper side of the connecting hole;

[0007] The drill bit body has two pairs of symmetrically arranged water outlet holes. Each pair of water outlet holes is arranged parallel to each other in the groove between the cutting edges. The drill bit body has a pair of symmetrically arranged air inlets, and one air inlet corresponds to the groove where the pair of water outlet holes are located. A first slag discharge groove is formed between the cutting edges. A second slag discharge groove is formed on the lower outer side of the drill bit body. The second slag discharge groove is connected to the first slag discharge groove one by one.

[0008] Both the water outlet and the air inlet are through holes, and they are connected through the transition cavity. The air inlet is located between a pair of water outlets arranged vertically. The inner diameter of the connecting hole is larger than the diameter of the transition cavity. The water outlet is a flared hole with a larger inner diameter and a smaller outer diameter. A first inclined block is pressed onto the end of the transition cavity. The lower end face of the first inclined block is arc-shaped and flush with the inner end of the water outlet on the upper side. The angle between the air inlet, the water outlet and the center line of the transition cavity is 40° to 50°.

[0009] As a preferred embodiment of the above solution, a connecting part is provided on the lower side of the connecting hole, the connecting part includes a connecting frame, a circular through hole is provided on the upper side of the connecting frame, the diameter of the circular through hole matches the inner diameter of the connecting hole, a limiting groove is provided on the lower side of the connecting hole, and the connecting frame is inserted into the limiting groove and locked and fixed by a fastening component.

[0010] More preferably, the upper side of the connecting frame is fixed to the inner wall of the limiting groove by a vertically installed first screw, the lower side of the connecting frame is connected to the lower side of the connecting hole by a vertically installed second screw, a groove is provided on the outer side of the connecting hole, and the side wall of the connecting frame is connected to the side wall of the connecting hole by a countersunk bolt installed horizontally in the groove.

[0011] More preferably, one side of the countersunk bolt penetrates the wall of the connecting hole and is threaded to the side wall of the connecting frame, and an arc-shaped elastic clamping piece is provided at the inner end of each countersunk bolt.

[0012] More preferably, a second inclined block is press-fitted at the connection point between the connecting hole and the transition cavity.

[0013] More preferably, the air inlet and water outlet are at an angle of 45° to the center line of the transition cavity.

[0014] A further preferred embodiment is that the air inlet is provided with a plurality of baffles, which are alternately arranged at intervals above and below.

[0015] The beneficial effects of this invention are:

[0016] 1. By adding two pairs of funnel-shaped water outlets to the drill bit body and changing the diameter of the water outlet end, the water pressure is increased to ensure water output and improve chip removal. The position setting of the pair of air inlets further increases the water outlet pressure and chip removal effect. The addition of the first and second inclined blocks reduces energy loss at the connection between the fluid inside the anchor rod and the drill bit, preventing pressure drop.

[0017] 2. A detachable connecting bracket is added to the lower side of the connecting hole. During the assembly of the drill bit body, the anchor rod is further clamped and tightened by the arc-shaped elastic clamping plate, which increases the tightness of the connection between the drill bit body and the anchor rod and increases the running stability of the drill bit body. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0019] Figure 2 This is a schematic diagram of the front cross-sectional structure of the present invention.

[0020] Figure 3 This is a bottom-view structural diagram of the present invention.

[0021] Figure 4 For the present invention Figure 2 Enlarged diagram of point A in the middle.

[0022] Figure 5 For the present invention Figure 3 Enlarged diagram of point B in the middle.

[0023] In the diagram: 1. Drill bit body, 2. Cross blade, 3. Connecting hole, 4. Threaded connection, 5. Transition cavity, 6. Water outlet, 7. Air inlet, 8. First slag discharge trough, 9. Second slag discharge trough, 10. Connecting frame, 11. First screw, 12. Second screw, 13. Groove, 14. Countersunk bolt, 15. Elastic clamping piece, 16. Baffle plate, 17. Second inclined block, 18. First inclined block. Detailed Implementation

[0024] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] like Figure 1-5 As shown, a self-drilling hollow anchor drill bit includes a drill bit body 1, a cross blade 2 on the drill bit body 1, a connecting hole 3 on the lower side of the drill bit body 1, a threaded connection part 4 on the inner wall of the connecting hole 3, and a transition cavity 5 on the upper side of the connecting hole 3.

[0026] The drill bit body 1 has two pairs of symmetrically arranged water outlet holes 6, totaling four water outlet holes 6. Each pair of water outlet holes 6 is arranged parallel to each other vertically in the groove between the cutting edges. The drill bit body 1 also has a pair of symmetrically arranged air inlets 7, with each air inlet 7 corresponding to a groove containing a pair of water outlet holes 6. Four first-stage cuttings channels 8 are formed between the cutting edges. Four second-stage cuttings channels 9 are formed on the lower outer side of the drill bit body 1, corresponding one-to-one with the first-stage cuttings channels 8, and are arranged parallel to the axis of the drill bit body 1. The cuttings generated during drilling are discharged sequentially through the first-stage cuttings channels 8 and the second-stage cuttings channels 9. Compared to having only a single first-stage cuttings channel 8, this method more effectively prevents cuttings from accumulating at the front end of the drill bit body 1, thus avoiding hindering drilling and improving drilling efficiency.

[0027] Both the water outlet 6 and the air inlet 7 are through holes, and they are connected by the transition cavity 5. The air inlet 7 is located between a pair of water outlets 6 arranged vertically, and the inner diameter of the connecting hole 3 is larger than the diameter of the transition cavity 5. The water outlet 6 is a flared hole with a larger inner diameter and a smaller outer diameter. A first inclined block 18 is press-fitted onto the end of the transition cavity 5. The lower end face of the first inclined block 18 is arc-shaped and flush with the inner end of the upper water outlet 6. The angle between the air inlet 7, the water outlet 6, and the center line of the transition cavity 5 is 40° to 50°, preferably 45°.

[0028] A connecting part is provided on the lower side of the connecting hole 3. The connecting part includes a connecting bracket 10. A circular through hole is provided on the upper side of the connecting bracket 10. The diameter of the circular through hole matches the inner diameter of the connecting hole 3. A limiting groove is provided on the lower side of the connecting hole 3. The connecting bracket 10 is inserted into the limiting groove and locked and fixed by a fastening component.

[0029] The upper side of the connecting frame 10 is fixedly mounted on the inner wall of the limiting groove by a vertically installed first screw 11. The lower side of the connecting frame 10 is connected to the lower side of the connecting hole 3 by a vertically installed second screw 12. A groove 13 is provided on the outer side of the connecting hole 3. The side wall of the connecting frame 10 is connected to the side wall of the connecting hole 3 by a countersunk bolt 14 horizontally installed in the groove 13. One side of the countersunk bolt 14 penetrates the wall of the connecting hole 3 and is threaded to the side wall of the connecting frame 10. An arc-shaped elastic clamping piece 15 is provided at the inner end of each countersunk bolt 14. A second inclined block 17 is press-fitted at the connection between the connecting hole 3 and the transition cavity 5.

[0030] When carrying out rock mass reinforcement projects under complex geological conditions such as tunnel pre-support, slope treatment, and high ground stress and large deformation, self-drilling anchor bolts are required. Before use, the drill bit body 1 needs to be connected to the anchor bolt. First, the connecting frame 10 is inserted into the connecting hole 3, and the connecting frame 10 can be installed on the lower side of the connecting hole 3 by using the first screw 11 and the second screw 12 respectively. Then, the countersunk bolt 14 is inserted into the groove 13 and threadedly connected to the connecting frame 10. At this time, the anchor bolt is inserted into the connecting hole 3, and the initial connection between the drill bit body 1 and the anchor bolt is achieved through the threaded connection part 4.

[0031] At this time, the upper side of the anchor rod will abut against the second inclined block 17, and the operator will rotate the countersunk bolt 14, thereby pushing the elastic clamping piece 15 to fit tightly against the anchor rod, thereby increasing the tightness of the connection between the anchor rod and the drill bit body 1 and increasing the connection strength.

[0032] The self-drilling anchor is then connected to the anchor drilling machine, which can simultaneously perform drilling, grouting, and anchoring functions. During this process, in order to increase the chip removal effect, water needs to be introduced into the anchor to facilitate the removal of waste chips. At this time, the water will be discharged through two pairs of water outlets 6. The first inclined block 18 is used to change the direction of water flow and reduce the impact of water flow on the inner wall of the transition cavity 5, which causes kinetic energy loss. Since the number of water outlets 6 has been increased in this case, the water flow pressure will decrease. Therefore, the water outlets 6 are designed as a funnel shape. The inner diameter of the water outlet end of the water outlet 6 is smaller than the inner diameter of the water inlet end. Due to the reduction in the inner diameter, the pressure and flow rate of the discharged water will increase, thereby increasing the impact force of the water flow and increasing the chip removal effect at this time.

[0033] At the same time, a low pressure situation will occur at the water inlet end of the water outlet 6. At this time, the air inlet 7 can draw in outside air and introduce it into the transition cavity 5, thereby increasing the speed at which the water flows into the transition cavity 5 and the speed at which the water flows out of the water outlet 6, further increasing the water pressure, thereby increasing the chip removal effect when the drill bit body 1, together with the cross blade 2, the first chip removal groove 8 and the second chip removal groove 9, performs drilling operations.

[0034] A baffle plate 16 is installed inside the air intake 7. The baffle plates 16 are arranged alternately at intervals to reduce the occurrence of debris entering the air intake 7 and causing blockage.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A self-drilling hollow anchor drill bit, comprising a drill bit body (1), wherein a cross-shaped cutting edge (2) is provided on the drill bit body (1), a connecting hole (3) is provided on the lower side of the drill bit body (1), a threaded connection part (4) is provided on the inner wall of the connecting hole (3), and a transition cavity (5) is provided on the upper side of the connecting hole (3), characterized in that: The drill bit body (1) has two pairs of symmetrically arranged water outlet holes (6). Each pair of water outlet holes (6) is arranged parallel to each other in the groove between the cutting edges. The drill bit body (1) has a pair of symmetrically arranged air inlets (7), and one air inlet (7) corresponds to the groove where the pair of water outlet holes (6) are located. A first slag discharge groove (8) is formed between the cutting edges. A second slag discharge groove (9) is opened on the lower outer side of the drill bit body (1). The second slag discharge groove (9) is connected to the first slag discharge groove (8) in a one-to-one correspondence. The water outlet (6) and air inlet (7) are both through holes, and they are connected through the transition cavity (5). The air inlet (7) is located between a pair of water outlets (6) arranged vertically. The inner diameter of the connecting hole (3) is larger than the diameter of the transition cavity (5). The water outlet (6) is a horn-shaped hole with a larger inner diameter and a smaller outer diameter. The end of the transition cavity (5) is press-fitted with a first inclined block (18). The lower end face of the first inclined block (18) is arc-shaped and flush with the inner end of the water outlet (6) on the upper side. The angle between the air inlet (7), the water outlet (6) and the center line of the transition cavity (5) is 40° to 50°.

2. The self-drilling hollow anchor drill bit according to claim 1, characterized in that, A connecting part is provided on the lower side of the connecting hole (3). The connecting part includes a connecting frame (10). A circular through hole is provided on the upper side of the connecting frame (10). The diameter of the circular through hole matches the inner diameter of the connecting hole (3). A limiting groove is provided on the lower side of the connecting hole (3). The connecting frame (10) is inserted into the limiting groove and locked and fixed by a fastening component.

3. A self-drilling hollow anchor drill bit according to claim 2, characterized in that, The upper side of the connecting frame (10) is fixed to the inner wall of the limiting groove by a vertically installed first screw (11). The lower side of the connecting frame (10) is connected to the lower side of the connecting hole (3) by a vertically installed second screw (12). A groove (13) is provided on the outer side of the connecting hole (3). The side wall of the connecting frame (10) is connected to the side wall of the connecting hole (3) by a countersunk bolt (14) installed horizontally in the groove (13).

4. A self-drilling hollow anchor drill bit according to claim 3, characterized in that, The countersunk bolt (14) penetrates the wall of the connecting hole (3) on one side and is threaded to the side wall of the connecting frame (10). Each countersunk bolt (14) has an arc-shaped elastic clamping piece (15) at its inner end.

5. A self-drilling hollow anchor drill bit according to claim 1, characterized in that, A second inclined block (17) is press-fitted at the connection point between the connecting hole (3) and the transition cavity (5).

6. A self-drilling hollow anchor drill bit according to claim 1, characterized in that, The air inlet (7) and water outlet (6) form a 45° angle with the center line of the transition cavity (5).

7. A self-drilling hollow anchor drill bit according to claim 1, characterized in that, The air inlet (7) is provided with several baffles (16), which are arranged alternately at intervals.

Images