A drill bit for thermal expansion blasting

Abstract

The application relates to the technical field of drilling bits, and discloses a thermal expansion drilling bit for blasting, which comprises a drill body, four protrusions arranged at the bottom of the drill body, a group of drill teeth connected to the protrusions, a side drilling assembly arranged on the drill body, four sliding blocks slidingly connected to the four protrusions respectively, a group of side blades connected to the sliding blocks, a chisel hitting assembly arranged on the drill body, and a chisel head. The arrangement of the side drilling assembly enables four groups of side blades to realize self-adaptive expansion and contraction according to drilling resistance. When drilling in relatively hard rock strata, the side blades are retracted according to the increase of the drilling resistance, so as to reduce the contact area and the drilling resistance, and avoid the breakage of the side blades or the drill rod; when drilling in relatively soft rock strata, the side blades are extended according to the decrease of the drilling resistance, so as to increase the contact area and improve the breaking efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drilling bits, in particular to a thermal expansion blasting drilling bit. BACKGROUND

[0002] Thermal expansion blasting is a non-explosive blasting technology that uses the expansion pressure generated by the rapid gasification of a medium under heat to cause rock mass to break, and has the characteristics of safety, environmental protection, and no flying stones, and is widely used in earthwork engineering near sensitive facilities. The operation steps usually include: first, drilling operation, drilling holes of a specific diameter and depth according to design parameters, then loading cracking tubes and other equipment into the holes, causing the medium to gasify and expand by heating, generating high pressure to crack the rock mass, and finally mechanically cleaning the broken rock mass; among them, drilling operation is the key front link of thermal expansion blasting, and the diameter, depth, and perpendicularity of the drilled hole must meet the design requirements to ensure the cracking effect. Drilling operation relies on the drill bit to complete, and the conventional drill bit usually includes a drill shaft, a drill handle, an end blade, and a side blade. The drill handle is connected to the drilling machine to transmit power, and the drill shaft directly contacts the rock formation to break it, and rotation and axial feed are used to drill, providing a basis for the smooth implementation of subsequent thermal expansion blasting.

[0003] However, the existing technology has the following problems:

[0004] In the prior art, the side blade of the drill bit is usually designed as a fixed protrusion. When drilling hard rock layers, the contact area between the side blade and the rock layer remains unchanged, which increases the cutting resistance and easily causes the blade to overload and crack, and the wear is accelerated. Therefore, frequent downtime and replacement of the side blade or drill bit are required, which not only increases the cost of equipment, but also may cause delays in the construction period. At the same time, the increase in the cutting resistance of the side blade also increases the overall drilling resistance, which increases the torque on the drill rod, and may cause bending or even breaking of the drill rod, affecting the continuity of the operation. SUMMARY

[0005] The present application aims to solve the above problems and provides a thermal expansion blasting drilling bit that overcomes the defects of the existing drill bit side blade that easily cracks and wears when contacting hard rock. Details are described below.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] The application provides a drill bit for thermal expansion blasting, which comprises a drill body, four protrusions are arranged at the bottom of the drill body, a set of drill teeth are connected to the protrusions, and a grinding roller is rotatably arranged at the bottom of the protrusions; the drill body is provided with a side drilling assembly, the side drilling assembly comprises four sliding blocks, the four sliding blocks are respectively slidably connected in the four protrusions, a set of side blades are connected to the sliding blocks, the side blades penetrate the protrusions, a mandrel is rotatably connected to the top of the drill body, the mandrel can drive the drill body to rotate when rotating, the four sliding blocks can self-adaptively slide according to the drilling resistance of the drill body, and the length of the side blades protruding from the surface of the protrusions can be adjusted through self-adaptive sliding; the drill body is provided with a chisel assembly, the chisel assembly comprises a chisel head, and the chisel head can chisel the drilling surface during the drilling process of the drill body.

[0008] Preferably, the outer wall of the mandrel is fixedly connected with a first push block and a second push block, the first push block and the second push block are centrally symmetrically arranged, the top of the drill body is fixedly connected with a first hollow block and a second hollow block, the first hollow block and the second hollow block are centrally symmetrically arranged, and a set of arc springs are connected between the first push block and the first hollow block and between the second push block and the second hollow block.

[0009] Preferably, the top end of the mandrel is fixedly connected with a drill handle, the bottom of the drill handle is rotatably connected with the top of the drill body, and the drill handle is used for being connected with a drilling machine.

[0010] Preferably, the inner walls of the first hollow block and the second hollow block are respectively slidably connected with sliding rods, the sliding rod in the first hollow block is fixedly connected with the second push block, the sliding rod in the second hollow block is fixedly connected with the first push block, the bottoms of the two sliding rods are respectively fixedly connected with connecting rods, a groove disc is rotatably arranged in the drill body, the bottoms of the two connecting rods are fixedly connected with the groove disc, and the side, away from the side blade, of the sliding block is fixedly connected with a sliding shaft.

[0011] Preferably, four arc-shaped grooves are circumferentially arranged on the groove disc, and the four sliding shafts are slidably connected with the four arc-shaped grooves of the four groove discs.

[0012] Preferably, the chisel head is vertically slidably connected to the bottom of the drill body, a fixing ring is connected to the outer wall of the chisel head, and a compression spring is connected between the fixing ring and the bottom of the drill body.

[0013] Preferably, the chisel assembly further comprises a rotating ring, the rotating ring is rotatably connected to the bottom of the drill body, a gear is connected to the end, close to the chisel head, of the grinding roller, a crown gear ring is connected to the bottom of the rotating ring, the four gears are all in mesh with the crown gear ring, four ratchet blocks are circumferentially arranged on the inner wall of the rotating ring, two short shafts are connected to the fixing ring, and the short shafts are in sliding contact with the ratchet blocks when moving.

[0014] As preferred, the bottom of the drill body is provided with a slag cleaning assembly, the slag cleaning assembly comprises four pry rods, the four pry rods are all rotationally installed on the bottom of the drill body, a plurality of push rods are connected to the pry rods, a ball head is connected to one end of the pry rod close to the swivel ring, and an annular inclined groove is formed in the outer wall of the swivel ring.

[0015] As preferred, the four pry rods are respectively located in the four gaps formed by the four protrusions, and the four ball heads are in sliding contact with the annular inclined groove.

[0016] The beneficial effects are that:

[0017] 1. The drill bit for thermal expansion blasting, through the setting of the side drilling assembly, four groups of side blades can realize self-adaptive expansion and contraction according to the drilling resistance: when drilling in relatively hard rock strata, the side blades shrink according to the increase of the drilling resistance to reduce the contact area and the drilling resistance, so as to avoid the side blade cracking or the drill rod breaking; when drilling in relatively soft rock strata, the side blades extend according to the decrease of the drilling resistance to increase the contact area and improve the crushing efficiency. This linkage design balances the drilling requirements of different rock strata, ensures the stability of hard rock operation, improves the efficiency of soft rock operation, reduces equipment wear and tear, and avoids delay of the construction period.

[0018] 2. The drill bit for thermal expansion blasting, through the setting of the chisel impact assembly, the chisel head is driven by the ratchet block rotating with the grinding roller and cooperates with the compression spring to realize the effect of continuous downward impact. When encountering large stones, the chisel head first breaks them, and then the grinding roller further grinds them, solving the problem of low efficiency of simple grinding on large rocks, effectively improving the crushing speed of hard rock strata, and achieving the technical effects of guaranteeing the continuity of drilling and improving the overall operation efficiency.

[0019] 3. The drill bit for thermal expansion blasting, through the setting of the slag cleaning assembly, when the pry rod rotates with the swivel ring, it reciprocates by cooperating with the ball head through the annular inclined groove, and drives the push rod to continuously push the impurities such as soil and rock debris in the protrusion gap. This design avoids the accumulation of impurities to block the protrusion gap, ensures the smoothness of the slag discharge channel, prevents the drilling from being stuck due to the blockage of the protrusion gap, and achieves the technical effects of maintaining the slag discharge efficiency and ensuring the stable operation of the drilling. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, 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 are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 is a schematic diagram of the overall structure of the present application;

[0022] Figure 2 is the structure schematic diagram of the side drilling assembly of the present application;

[0023] Figure 3 is the structure schematic diagram of the mandrel of the present application;

[0024] Figure 4 is the structure schematic diagram of the slide bar of the present application;

[0025] Figure 5 is the structure schematic diagram of the connecting rod of the present application;

[0026] Figure 6 is the structure schematic diagram of the groove disc of the present application;

[0027] Figure 7 is the structure schematic diagram of the chisel assembly of the present application;

[0028] Figure 8 is the structure schematic diagram of the swivel ring of the present application;

[0029] Figure 9 is the structure schematic diagram of the ratchet block of the present application;

[0030] Figure 10 is the structure schematic diagram of the short shaft of the present application;

[0031] Figure 11 is the structure schematic diagram of the slag cleaning assembly of the present application;

[0032] Figure 12 is the structure schematic diagram of the ball head of the present application.

[0033] The reference signs are explained as follows: 1, drill body; 2, protruding block; 3, drill bit; 4, grinding roller; 8, drill handle;

[0034] 5, side drilling assembly; 51, mandrel; 52, first push block; 53, second push block; 54, first hollow block; 55, second hollow block; 56, slide bar; 57, arc spring; 58, connecting rod; 59, groove disc; 510, slide block; 511, side blade; 512, slide shaft;

[0035] 6, chisel assembly; 61, chisel head; 62, swivel ring; 63, crown tooth ring; 64, gear; 65, ratchet block; 66, fixed ring; 67, compression spring; 68, short shaft;

[0036] 7, slag cleaning assembly; 71, pry bar; 72, lever; 73, ball head; 74, annular chute. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0038] Embodiment 1

[0039] The existing drill bit is usually provided with a convex side blade, which plays a role in breaking and cutting the side of the hole. However, when the rock stratum in the hole is hard, the cutting resistance of the side blade increases, which easily leads to the overload collapse and the accelerated wear of the blade part, and frequent downtime replacement is required, which increases the equipment cost and the risk of delay in construction period. In addition, the increase in the cutting resistance of the side blade also leads to the increase in the drilling resistance of the drill bit, which makes the drill rod prone to bending or even breaking due to excessive torque. To solve the above problems, the embodiment is invented.

[0040] Please refer to Figure 1 Figure 6 A hot expansion blasting drill bit, comprising a drill body 1, four protrusions 2 are arranged at the bottom of the drill body 1, a group of drill teeth 3 are connected to the protrusions 2, a grinding roller 4 is rotatably installed at the bottom of the protrusions 2, the protrusions 2 protrude from the bottom of the drill body 1, the edges of the protrusions 2 and the drill teeth 3 can play a cutting role during drilling, and the grinding roller 4 directly contacts the drilling surface in the hole during drilling to play a grinding and breaking effect. During drilling, a water injection device needs to be used to continuously inject water into the hole to play a role in cooling and discharging drill cuttings.

[0041] Further, the drill body 1 is provided with a side drilling assembly 5, the side drilling assembly 5 comprises four sliding blocks 510, the four sliding blocks 510 are respectively slidably connected in the four protrusions 2, a group of side blades 511 are connected to the sliding blocks 510, the side blades 511 penetrate the protrusions 2, a mandrel 51 is rotatably connected to the top of the drill body 1, the mandrel 51 can drive the drill body 1 to rotate when rotating, the four sliding blocks 510 can adaptively slide according to the drilling resistance of the drill body 1, the sliding blocks 510 can adjust the length of the side blades 511 protruding from the surface of the protrusions 2 through adaptive sliding, and the parts of the side blades 511 protruding from the protrusions 2 can play a role in breaking and cutting the side of the hole, thereby improving the drilling efficiency.

[0042] ​Further, the outer wall of the mandrel 51 is fixedly connected with the first push block 52 and the second push block 53, the first push block 52 and the second push block 53 are centrally symmetrically arranged, the top of the drill body 1 is fixedly connected with the first hollow block 54 and the second hollow block 55, the first hollow block 54 and the second hollow block 55 are centrally symmetrically arranged, a group of arc springs 57 are connected between the first push block 52 and the first hollow block 54 and between the second push block 53 and the second hollow block 55 respectively, the top end of the mandrel 51 is fixedly connected with the drill handle 8, the bottom of the drill handle 8 is rotatably connected with the top of the drill body 1, the drill handle 8 is used for being connected with a drilling machine, after the drill handle 8 is connected with the drilling machine, the drilling machine drives the drill handle 8 to rotate (for reference Figure 3 direction is clockwise rotation, the following text is based on this rotation direction as the reference), the mandrel 51 is driven by the drill handle 8 to rotate clockwise, when the mandrel 51 rotates clockwise, the two groups of arc springs 57 are extruded by the first push block 52 and the second push block 53, the two groups of arc springs 57 exert pressure on the first hollow block 54 and the second hollow block 55, so as to achieve the effect that when the first push block 52 and the second push block 53 rotate clockwise, the first hollow block 54 and the second hollow block 55 are driven by the two groups of arc springs 57 to rotate clockwise, when the first hollow block 54 and the second hollow block 55 rotate clockwise, the drill body 1 is driven to rotate clockwise, when the drill body 1 rotates, drilling operation is performed.

[0043] In addition, the inner walls of the first hollow block 54 and the second hollow block 55 are respectively connected with sliding rods 56, the sliding rod 56 in the first hollow block 54 is fixedly connected with the second push block 53, the sliding rod 56 in the second hollow block 55 is fixedly connected with the first push block 52, the bottoms of the two sliding rods 56 are respectively fixedly connected with connecting rods 58, a groove disc 59 is rotatably installed in the drill body 1, the bottoms of the two connecting rods 58 are fixedly connected with the groove disc 59, the side away from the side blade 511 of the sliding block 510 is fixedly connected with a sliding shaft 512, four arc-shaped grooves are circumferentially arranged on the groove disc 59, the four sliding shafts 512 are respectively slidably connected with the four arc-shaped grooves of the groove disc 59, when the drill body 1 is working and is subjected to a drilling resistance, the drilling resistance will cause the two groups of arc-shaped springs 57 to be compressed, so that the first push block 52 and the first hollow block 54 are close to each other, and the second push block 53 and the second hollow block 55 are also close to each other, so that the first push block 52 and the second push block 53 respectively drive the two sliding rods 56 to slide in the first hollow block 54 and the second hollow block 55, and when the two sliding rods 56 move, the groove disc 59 is driven to rotate clockwise by the two connecting rods 58, when the groove disc 59 rotates clockwise, the four sliding shafts 512 can be driven to move to positions close to the center of the groove disc 59 through the four arc-shaped grooves, conversely, when the groove disc 59 rotates counterclockwise, the four sliding shafts 512 can be driven to move to positions away from the center of the groove disc 59 through the four arc-shaped grooves, and when the sliding shaft 512 moves, the sliding block 510 can be driven to move synchronously, therefore, when the four groups of side blades 511 are subjected to a large resistance during drilling operation, the four groups of side blades 511 will transmit the drilling resistance to the drill body 1, finally the groove disc 59 rotates clockwise and drives the four sliding blocks 510 to move close to the groove disc 59 through the four sliding shafts 512, so that the four groups of side blades 511 shrink into the four protrusions 2, the greater the drilling resistance, the greater the shrinkage of the four groups of side blades 511, and after the four groups of side blades 511 shrink, the contact area with the rock stratum can be reduced, so that the drilling resistance is reduced, the longer the length of the side blade 511 protruding from the surface of the protrusion 2, the higher the rock stratum breaking efficiency, and the drilling efficiency can be improved, the shorter the length of the side blade 511 protruding from the surface of the protrusion 2, the lower the breaking efficiency, but the drilling resistance can be greatly reduced, so that stable operation is ensured, through the arrangement of the side drilling assembly 5, when the four groups of side blades 511 drill hard rock stratum, because the side blades 511 are subjected to a large drilling resistance, the side blades 511 shrink inward, so that the contact area with the rock stratum is reduced, and the drilling resistance is reduced, so that low-efficiency but stable drilling operation mode is entered, and the side blades 511 are prevented from breaking and the drill body 1 from deforming; when the four groups of side blades 511 drill fragile rock stratum, the four groups of side blades 511 can extend outward, so that the contact area with the rock stratum is increased, so that the drilling efficiency is improved as much as possible within a reasonable drilling resistance range.

[0044] Example 2

[0045] On the basis of embodiment 1, in the drilling process, the drilling face of the drilling hole can be ground and broken by the four grinding rollers 4, but when encountering larger stones, the grinding and breaking efficiency will be affected, in order to solve the above problems, the embodiment is invented.

[0046] Please refer to Figure 1 、 Figure 7 - Figure 10 , the drill body 1 is provided with a chisel assembly 6, the chisel assembly 6 includes a chisel head 61, the chisel head 61 can chisel the drilling face in the drilling process of the drill body 1, the chisel head 61 is vertically and slidingly connected at the bottom of the drill body 1, the outer wall of the chisel head 61 is connected with a fixing ring 66, the fixing ring 66 and the bottom of the drill body 1 are connected with a compression spring 67, the upward thrust applied to the fixing ring 66 can drive the chisel head 61 to move upward, at the same time the compression spring 67 is compressed, when the upward thrust applied to the fixing ring 66 is lost, the compression spring 67 drives the chisel head 61 to impact downward by the elastic force, so as to achieve the effect of chiseling the drilling face.

[0047] It is worth noting that the chisel assembly 6 further includes a rotating ring 62, the rotating ring 62 is rotationally connected at the bottom of the drill body 1, the end of the grinding roller 4 close to the chisel head 61 is connected with a gear 64, the bottom of the rotating ring 62 is connected with a crown gear ring 63, the four gears 64 are all engaged with the crown gear ring 63, the inner wall of the rotating ring 62 is circumferentially and arrayedly connected with four ratchet blocks 65, the fixing ring 66 is connected with two short shafts 68, the short shafts 68 are in sliding contact with the ratchet blocks 65 when moving, the grinding roller 4 rotates in the drilling process by utilizing the friction force with the drilling contact surface, the four grinding rollers 4 drive the crown gear ring 63 to rotate clockwise through the four gears 64 when rotating, the crown gear ring 63 drives the rotating ring 62 to rotate clockwise, the four ratchet blocks 65 in the rotating ring 62 synchronously rotate clockwise, the ratchet blocks 65 are provided with climbing surfaces and vertical surfaces, when the four ratchet blocks 65 rotate clockwise, two of the ratchet blocks 65 drive the two short shafts 68 by the climbing surfaces, so that the two short shafts 68 drive the fixing ring 66 and the chisel head 61 to move upward, due to the elastic force of the compression spring 67, the two short shafts 68 maintain downward pressure, when the two short shafts 68 are separated from the climbing surfaces of the two ratchet blocks 65, the two short shafts 68 quickly move downward along the vertical surfaces of the two ratchet blocks 65, so that the chisel head 61 impacts downward, then the climbing surfaces of the other two ratchet blocks 65 are in contact with the two short shafts 68, the chisel head 61 moves upward again, so as to achieve that the chisel head 61 can constantly move upward and then impact downward in the drilling operation, so as to achieve the technical effect of chiseling the drilling face, so as to break larger stones, after breaking the larger stones, the grinding and breaking efficiency of the four grinding rollers 4 can be improved, so as to improve the drilling efficiency.

[0048] Embodiment 3

[0049] On the basis of embodiment 2, during drilling operation, impurities may be stuck in the gap between the four protrusions 2, and after long time use, the impurities fill the gap, which causes the four protrusions 2 to be blocked from contacting the inside of the drill hole, thereby affecting the drilling efficiency and the slag discharge efficiency.

[0050] Please refer to Figure 1 、 Figure 7 、 Figure 11 、 Figure 12 The drill body 1 is provided with a slag removal assembly 7 at the bottom, and the slag removal assembly 7 includes four pry bars 71, each of which is rotatably installed at the bottom of the drill body 1. The pry bar 71 is connected with a plurality of push rods 72, and the end of the pry bar 71 close to the swivel ring 62 is connected with a ball head 73. The outer wall of the swivel ring 62 is provided with an annular inclined groove 74. The four pry bars 71 are respectively located in the four gaps formed by the four protrusions 2, and the four ball heads 73 are in sliding contact with the annular inclined groove 74. When the swivel ring 62 rotates, the annular inclined groove 74 rotates with it. Taking one of the pry bars 71 as an example, the annular inclined groove 74 can move the pry bar 71 up and down through the ball head 73 during rotation, so that the pry bar 71 continuously reciprocates. When the pry bar 71 reciprocates, the impurities in the gap between the protrusions 2 can be continuously pushed by the plurality of push rods 72, so that the impurities in the gap between the protrusions 2 always keep moving, avoiding the situation that the impurities are stuck in the gap between the protrusions 2 due to static, thereby ensuring the slag discharge efficiency and the normal operation of the drilling operation.

[0051] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A drilling bit for thermal expansion blasting, characterized in that, include: The drill body (1) has four protrusions (2) at its bottom, and a set of drill teeth (3) are connected to the protrusions (2). A grinding roller (4) is rotatably installed at the bottom of the protrusions (2). The drill body (1) is provided with a side drilling assembly (5), which includes four sliders (510). The four sliders (510) are slidably connected to four protrusions (2). A set of side cutting edges (511) is connected to the sliders (510). The side cutting edges (511) penetrate the protrusions (2). The top of the drill body (1) is rotatably connected to a mandrel (51). When the mandrel (51) rotates, it can drive the drill body (1) to rotate. The four sliders (510) can adaptively slide according to the drilling resistance of the drill body (1). The sliders (510) can adjust the length of the side cutting edges (511) protruding from the surface of the protrusions (2) by adaptive sliding. The drill body (1) is provided with a striking assembly (6), which includes a chisel head (61) capable of striking the drilling surface during the drilling process of the drill body (1). The outer wall of the mandrel (51) is fixedly connected to a first push block (52) and a second push block (53). The first push block (52) and the second push block (53) are centrally symmetrically arranged. The top of the drill body (1) is fixedly connected to a first hollow block (54) and a second hollow block (55). The first hollow block (54) and the second hollow block (55) are centrally symmetrically arranged. A set of arc springs (57) are respectively connected between the first push block (52) and the first hollow block (54) and between the second push block (53) and the second hollow block (55). The inner walls of the first hollow block (54) and the second hollow block (55) are respectively slidably connected with sliding rods (56). The sliding rod (56) in the first hollow block (54) is fixedly connected to the second push block (53), and the sliding rod (56) in the second hollow block (55) is fixedly connected to the first push block (52). The bottom of the two sliding rods (56) is fixedly connected with connecting rods (58). A grooved plate (59) is rotatably installed inside the drill body (1). The bottom ends of the two connecting rods (58) are fixedly connected to the grooved plate (59). A sliding shaft (512) is fixedly connected to the side of the slider (510) away from the side blade (511). The slotted disk (59) has four arc-shaped slots arranged in a circular array, and the four sliding shafts (512) are respectively slidably connected to the four arc-shaped slots of the four slotted disks (59).

2. The drilling bit for thermal expansion blasting according to claim 1, characterized in that: The top end of the mandrel (51) is fixedly connected to a drill shank (8), the bottom of the drill shank (8) is rotatably connected to the top of the drill body (1), and the drill shank (8) is used to connect with the drilling machine.

3. A drilling bit for thermal expansion blasting according to claim 1, characterized in that: The chisel head (61) is vertically slidably connected to the bottom of the drill body (1). A fixing ring (66) is connected to the outer wall of the chisel head (61). A compression spring (67) is connected between the fixing ring (66) and the bottom of the drill body (1).

4. A drilling bit for thermal expansion blasting according to claim 3, characterized in that: The chisel assembly (6) also includes a rotating ring (62), which is rotatably connected to the bottom of the drill body (1). The grinding roller (4) is connected to a gear (64) at one end near the chisel head (61). A crown tooth ring (63) is connected to the bottom of the rotating ring (62). All four gears (64) mesh with the crown tooth ring (63). Four ratchet blocks (65) are connected in a circumferential array on the inner wall of the rotating ring (62). Two short shafts (68) are connected on the fixed ring (66). The short shafts (68) slide in contact with the ratchet blocks (65) when moving.

5. A drilling bit for thermal expansion blasting according to claim 4, characterized in that: The bottom of the drill body (1) is provided with a slag removal assembly (7), which includes four pry bars (71). All four pry bars (71) are rotatably installed at the bottom of the drill body (1). Multiple levers (72) are connected to the pry bars (71). A ball head (73) is connected to one end of the pry bar (71) near the rotating ring (62). An annular inclined groove (74) is provided on the outer wall of the rotating ring (62).

6. A drilling bit for thermal expansion blasting according to claim 5, characterized in that: The four pry bars (71) are located in the four gaps formed by the four protrusions (2), and the four ball heads (73) are in sliding contact with the annular groove (74).

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