An eccentric drill bit for coal mine tunneling

Abstract

The utility model discloses an eccentric drill bit for coal mine tunneling, including the drill body, the cross section of drill body is circular, and the outer circumferential surface annular array of drill body has several concave arc grooves, and is equipped with cutting edge in each concave arc groove, and the weight of several cutting edges is not the same, the inner vertical surface of concave arc groove is oppositely provided with shaft hole, and the shaft hole is close to one side of concave arc groove, and cutting edge is equipped with the shaft rod of matching with shaft hole, and cutting edge is matched with the hole shaft of shaft rod through shaft hole, realizes the rotary connection with concave arc groove. Through the rotary connection of cutting edge and concave arc groove, when the drill body rotates, the end of cutting edge is thrown out from the concave arc groove due to the action of centrifugal force, at this moment, the drill body is pushed forward, and the coal seam is drilled, when the drill body needs to be withdrawn, the drill body is reversely rotated, and the cutting edge is withdrawn into the concave arc groove through the blocking force of the coal seam, so that the variable purpose of the outer diameter of drill body is realized.

Description

Technical Field

[0001] This utility model belongs to the technical field of coal mine tunneling equipment, and in particular relates to an eccentric drill bit for coal mine tunneling. Background Technology

[0002] Eccentric drill bits, through several cutting heads with eccentricity, generate periodic impact and shear combined forces on the peripheral cutters, breaking through the shear strength threshold of hard rock and solving the problem of hard rock jamming. For coal seams with fractures or well-developed fissures, such as those near faults, eccentric drill bits are often used to drill channels, and then grouting pipes are inserted to inject cement slurry or chemical slurry to fill the coal seam fissures, cement loose coal blocks, improve the compressive strength of the coal seam, and prevent roadway deformation or collapse.

[0003] To protect the eccentric drill bit and prevent stuck or buried drill accidents caused by coal seam collapse, a shoe is fitted onto the eccentric drill bit during drilling. The shoe is then threaded onto the casing. During operation, the shoe and casing protect the eccentric drill bit. After the operation is completed, the eccentric drill bit is pulled out of the casing, and cement grout or chemical grout is injected into the casing. In order for the shoe to follow the drill bit, the outer diameter of the eccentric drill bit must be larger than the shoe. However, when the eccentric drill bit needs to be pulled out after the operation is completed, it is easy for the eccentric drill bit to pull the shoe and casing out of the hole. Therefore, an eccentric drill bit with a variable outer diameter for coal mine tunneling has been designed. Utility Model Content

[0004] The purpose of this invention is to achieve a variable outer diameter of the drill bit by using a rotating connection between the cutting edge and the concave arc groove. When the drill body rotates, the end of the cutting edge is thrown out of the concave arc groove due to centrifugal force, thus advancing the drill body forward to drill into the coal seam. When the drill body needs to be retracted, it rotates in the opposite direction, and the cutting edge is retracted into the concave arc groove by the resistance force of the coal seam. This solves the problem in the above-mentioned background technology where the outer diameter of the eccentric drill bit is larger than that of the casing shoe, and the casing shoe and casing are taken out of the hole when the eccentric drill bit is pulled out after the operation is completed.

[0005] The specific technical solution of this utility model is as follows: An eccentric drill bit for coal mine tunneling includes a drill body with a circular cross-section. Several concave arc grooves are arranged in annular array on the outer circumference of the drill body. Each concave arc groove is equipped with a cutting edge, and the weights of the cutting edges are different. The inner surfaces of the concave arc grooves are provided with shaft holes, with the shaft holes close to the side of the concave arc grooves. The cutting edges are provided with shaft rods that are matched with the shaft holes. The cutting edges are rotatably connected to the concave arc grooves through the shaft hole and the shaft rod hole-shaft cooperation.

[0006] Furthermore, the depth of the concave groove is greater than the thickness of the cutting edge.

[0007] Furthermore, the length of the concave groove is greater than the length of the cutting edge.

[0008] Furthermore, the slag discharge trough penetrates the limiting component, and the limiting component has a circular cross-section.

[0009] Furthermore, several slag discharge channels are arranged in a ring along the central axis on the outer circumference of the drill body.

[0010] Furthermore, the slag discharge trough penetrates the limiting component.

[0011] Furthermore, the top surface of the cutting edge is provided with a slope, which is inclined towards the rear of the drill body, and several conical tips are provided on the slope.

[0012] Furthermore, the front face of the drill body is provided with several circular points.

[0013] Furthermore, the outer circumference of the drill body is provided with two concave arc grooves that are spaced apart along the axial direction.

[0014] Furthermore, the rear end of the drill body is provided with a shank for connecting the power unit, and the outer surface of the shank is provided with several retraction grooves along the axial direction.

[0015] Compared with the prior art, the present invention has the following beneficial effects: In use, the tube shoe is first fitted onto the drill body, then the casing is connected to the tube shoe, and the handle is connected to the power unit. The power unit is turned on to drive the drill body to rotate. Through the action of centrifugal force, the front end of the cutting edge is thrown out from the concave arc groove. Then the drill body is pushed to perform drilling operations on the coal seam. When the hole reaches the predetermined depth, the power unit drives the drill body to rotate in the opposite direction. Through the resistance force of the coal seam on the cutting edge, the cutting edge is retracted into the concave arc groove, thereby achieving the purpose of variable outer diameter of the drill body. This ensures that the tube shoe and casing will not be taken out of the hole when the drill body is retracted, reducing the error rate of drilling and grouting operations and improving the quality of operation. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the cutting edge in the open state in an embodiment of this utility model; Figure 2 This is a three-dimensional structural diagram of the cutting edge retracting into the concave arc groove in an embodiment of the present utility model; Figure 3 This is an exploded view of the assembly of the drill body, casing shoe, and casing in an embodiment of this utility model; Figure 4 This is a three-dimensional structural diagram of the drill body in an embodiment of the present utility model; Figure 5 This is a three-dimensional structural diagram of the cutting edge in an embodiment of the present invention; Figure label: 1. Drill body; 11. Concave arc groove; 111. Shaft hole; 12. Circular tip; 13. Slag discharge groove; 14. Limiting component; 15. Shank; 151. Retraction groove; 2. Cutting edge; 21. Shaft; 22. Tapered tip; 3. Boots; 31. Barrier components; 4. Sleeve. Detailed Implementation

[0017] To better understand the purpose, structure, and function of this utility model, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0018] In the description of this utility model, it should be understood that the terms "front" and "rear," etc., indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0019] See Figures 1 to 5This embodiment discloses an eccentric drill bit for coal mine tunneling, including a drill body 1 with a circular cross-section. A limiting member 14 with a circular cross-section is provided circumferentially at the rear end of the drill body 1. When the eccentric drill bit is in use, a shoe 3 is fitted over the drill body 1. A blocking member 31, which works in conjunction with the limiting member 14, is provided at the front end of the shoe 3. The cooperation between the blocking member 31 and the limiting member 14 ensures that the shoe 3 moves forward with the drill body 1 when drilling, preventing the shoe 3 from detaching from the drill body 1. A sleeve 4 is threadedly connected to the rear end of the shoe 3. The structure and connection method of the shoe 3 and the sleeve 4 are currently... The technology is well-known to those skilled in the art and will not be elaborated here. When the drill body 1 moves forward, the casing shoe 3 moves forward along with the casing 4 to complete the pipe laying operation. The outer circumference of the drill body 1 has several concave arc grooves 11 arranged in a ring. The concave arc grooves 11 are located in front of the limiting member 14. Each concave arc groove 11 is equipped with a cutting edge 2. The weights of the several cutting edges 2 are different. When the drill body 1 rotates, the different weights of the cutting edges 2 cause the center of rotation of the drill body 1 to deviate from the axis of the drill body 1. The several cutting edges 2 generate periodic impact and shear combined forces on the coal seam; the concave arc grooves 1 The inner surface of drill body 1 is provided with a shaft hole 111. The cutting edge 2 is provided with a shaft rod 21 that matches the shaft hole 111. The cutting edge 2 is rotated with the concave arc groove 11 through the shaft hole 111 and the shaft rod 21. The shaft hole 111 is close to the concave arc groove 11, so that when the cutting edge 2 opens from the concave arc groove 11, the outer diameter of drill body 1 is larger than the inner diameter of the shoe 3, which restricts the shoe 3 to drill body 1 and prevents it from detaching from drill body 1. Furthermore, one side of the concave arc groove 11 can abut against the opened cutting edge 2, and the side of the concave arc groove 11 that abuts against the cutting edge 2 can provide a reverse resistance force. To facilitate the crushing and drilling of the coal seam by the cutting edge 2, when using the eccentric drill bit, first put the shoe 3 on the drill body 1, then connect the casing 4 to the shoe 3, and connect the shank 15 to the power unit. Turn on the power unit to drive the drill body 1 to rotate. Through the action of centrifugal force, the front end of the cutting edge 2 is thrown out from the concave arc groove 11. Then push the drill body 1 to perform drilling operations on the coal seam. When the hole reaches the predetermined depth, the power unit drives the drill body 1 to rotate in the opposite direction. Through the resistance force of the coal seam on the cutting edge 2, the cutting edge 2 is retracted into the concave arc groove 11, thereby achieving the purpose of variable outer diameter of the drill body 1.

[0020] The depth of the concave arc groove 11 is greater than the thickness of the cutting edge 2. When the drill body 1 rotates in the opposite direction, the cutting edge 2 is pushed into the concave arc groove 11 due to the obstruction force of the coal seam. Since the depth of the concave arc groove 11 is greater than the thickness of the cutting edge 2, the cutting edge 2 can be retracted into the concave arc groove 11 as much as possible, without hindering the operation of the drill body 1 retracting into the tube shoe 3. Furthermore, the curvature of the bottom of the concave arc groove 11 is conducive to squeezing out the coal block in the concave arc groove 11 when the cutting edge 2 retracts into the concave arc groove 11. The depth of the concave arc groove 11 is greater than the thickness of the cutting edge 2, which can effectively prevent a small amount of coal slag from remaining in the concave arc groove 11. When the cutting edge 2 retracts into the concave arc groove 11, it will not hinder the operation of the drill body 1 retracting into the tube shoe 3. It can be further optimized that the contact surface between the cutting edge 2 and the concave arc groove 11 is an outwardly convex arc surface that matches the concave arc groove 11, which is more conducive to squeezing the coal slag out of the concave arc groove 11.

[0021] The length of the concave arc groove 11 is greater than the length of the cutting edge 2, so that a cavity is formed between the end of the cutting edge 2 and the side of the concave arc groove 11. This is beneficial for squeezing the coal slag out of the concave arc groove 11. Furthermore, when the cutting edge 2 retracts into the concave arc groove 11, the cavity between the end of the cutting edge 2 and the side of the concave arc groove 11 is beneficial for storing the coal slag that has not been squeezed out of the concave arc groove 11, without affecting the retraction of the cutting edge 2 into the concave arc groove 11.

[0022] Several slag discharge channels 13 are arranged in a ring along the central axis on the outer circumference of the drill body 1. The slag discharge channels 13 can guide the crushed coal slag at the front end of the drill body 1 to flow from the front end to the rear end.

[0023] The slag discharge trough 13 passes through the limiting member 14, and the coal slag can flow into the casing 4 through the slag discharge trough 13 and be discharged through the casing 4.

[0024] The top surface of the cutting edge 2 is provided with a slope, which is inclined to the rear of the drill body 1 to facilitate the forward movement of the drill body 1. Several conical tips 22 are provided on the slope, and the tips of the conical tips 22 are sharp, which ensures high centering accuracy during drilling and prevents the drill body 1 from deviating during drilling.

[0025] The front face of the drill body 1 is provided with several circular tips 12. The top of the circular tips 12 has a large contact surface with the coal seam, and the force is evenly distributed, which reduces the cracking and wear of the circular tips 12 and extends the service life of the drill body 1.

[0026] The outer circumference of the drill body 1 is provided with two concave arc grooves 11 that are spaced apart along the axial direction. The two concave arc grooves 11 are staggered. When the two cutting edges 2 are open, the contact surface between the drill body 1 and the coal seam is increased, thus improving the drilling efficiency.

[0027] The drill body 1 has a shank 15 at the rear end for connecting to the power unit. It can be further optimized that the shank 15 is a rectangular spline taper shank, and the outer surface of the shank 15 has several relief grooves 151 along the axial direction for connecting with the drilling machine.

[0028] Working principle: When in use, first put the shoe 3 on the drill body 1, then connect the casing 4 to the shoe 3, and connect the handle 15 to the power unit. Turn on the power unit to drive the drill body 1 to rotate. Through the action of centrifugal force, the front end of the cutting edge 2 is thrown out from the concave arc groove 11. Then push the drill body 1 to perform drilling operations on the coal seam. When the hole reaches the predetermined depth, the power unit drives the drill body 1 to rotate in the opposite direction. Through the resistance force of the coal seam on the cutting edge 2, the cutting edge 2 is retracted into the concave arc groove 11, thereby achieving the purpose of variable outer diameter of the drill body 1.

[0029] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An eccentric drill bit for coal mine tunneling, characterized in that: The drill body (1) has a circular cross-section and several concave arc grooves (11) arranged in annular array on the outer circumference of the drill body (1). Each concave arc groove (11) is equipped with a cutting edge (2), and the weights of the cutting edges (2) are different. The inner surfaces of the concave arc grooves (11) are provided with shaft holes (111), and the shaft holes (111) are close to the side of the concave arc grooves (11). The cutting edge (2) is provided with a shaft (21) that matches the shaft hole (111). The cutting edge (2) is connected to the concave arc groove (11) by the shaft hole (111) and the shaft (21) through the shaft hole (111).

2. The eccentric drill bit for coal mine tunneling according to claim 1, characterized in that, The depth of the concave groove (11) is greater than the thickness of the cutting edge (2).

3. The eccentric drill bit for coal mine tunneling according to claim 2, characterized in that, The length of the concave groove (11) is greater than the length of the cutting edge (2).

4. The eccentric drill bit for coal mine tunneling according to claim 1, characterized in that, The drill body (1) has a limiting member (14) in the circumferential direction at the rear end, and the limiting member (14) has a circular cross-section.

5. The eccentric drill bit for coal mine tunneling according to claim 4, characterized in that, Several slag discharge channels (13) are arranged in a ring along the central axis on the outer circumference of the drill body (1).

6. The eccentric drill bit for coal mine tunneling according to claim 5, characterized in that, Slag discharge trough (13) penetrates the limiting component (14).

7. The eccentric drill bit for coal mine tunneling according to claim 1, characterized in that, The top surface of the cutting edge (2) is provided with a slope, which is inclined to the rear of the drill body (1), and several conical tips (22) are provided on the slope.

8. The eccentric drill bit for coal mine tunneling according to claim 1, characterized in that, The front face of the drill body (1) has several circular tips (12).

9. The eccentric drill bit for coal mine tunneling according to claim 1, characterized in that, The outer circumference of the drill body (1) is provided with two concave arc grooves (11) that are spaced apart along the axial direction.

10. The eccentric drill bit for coal mine tunneling according to claim 1, characterized in that, The drill body (1) has a shank (15) at the rear end for connecting the power unit, and the outer surface of the shank (15) has several retraction grooves (151) along the axial direction.

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