Tower-shaped stepped drill bit

Abstract

The utility model relates to the technical field of drilling tools, in particular to a tower-shaped stepped drill bit. The tower-shaped stepped drill bit comprises a handle body and a drill body which are integrally connected, the drill body is formed by arranging a plurality of steps step by step, each step is provided with a cutting portion, a chip groove is formed in the side wall of the drill body, a crescent groove is formed in a main cutting edge of the cutting portion of the first step located at the tip of the drill body, and the crescent groove is communicated with the chip groove. An outer edge, an arc edge and an inner edge are sequentially formed on the main cutting edge in the direction from the outer side to the inner side of the drill body, the groove face of the chip groove is a front tool face, the end face of the first step is a first rear tool face, the main cutting edge is formed at the intersecting line of one side of the front tool face and the first rear tool face, and a rear edge is formed at the intersecting line of the other side of the front tool face and the first rear tool face. An arc groove is formed in the first rear cutter face and located in the rear edge. According to the tower-shaped stepped drill bit, the center positioning capacity is improved, swinging during drilling is reduced, and the drilling efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of drilling tools, in particular to a tower-shaped step drill bit. Background Art

[0002] A step drill is also called a conical drill or a pyramid drill. Its shape is similar to a cone, with a series of stepped diameters on it, and each step represents a specific hole size. When using it, you only need to select the appropriate step layer according to the required hole diameter to drill a hole of the corresponding size on the workpiece. In this way, a step drill can drill through holes of different diameters as needed, saving the time of repeatedly changing drill bits when processing personnel need to drill different hole diameters.

[0003] For example, Chinese patent document CN214394064U discloses a pagoda drill that can be connected to an electric wrench. The drill bit on the pagoda drill body is composed of four stepped edges, which makes the drill bit more labor-saving and wear-resistant when drilling, thereby reducing the user's use cost and further improving the applicability of the drill bit.

[0004] However, in the actual drilling process, if the workpiece lacks pre-drilled positioning holes, the pagoda drill bit is prone to deviate from the predetermined drilling position when drilling and lacks the ability to locate the center. Therefore, when drilling the first step hole, the pagoda drill bit needs to reduce the speed and then gradually increase the speed in order to ensure the processing position accuracy. This results in a slow start-up speed of the drill bit, which greatly affects the drilling efficiency. Summary of the invention

[0005] The technical problem to be solved by the utility model is to provide a drill bit structure for improving the center positioning capability, reducing the swing during drilling and improving the drilling efficiency during the drilling operation of the step drill.

[0006] In order to solve the above technical problems, the utility model proposes the following solutions:

[0007] A tower-shaped step drill bit comprises a handle body and a drill body connected in one piece, the drill body is composed of a plurality of steps arranged step by step, each step is provided with a cutting portion, and a chip removal groove is provided on the side wall of the drill body;

[0008] A crescent groove is arranged on the main cutting edge of the cutting portion of the first step located at the tip of the drill body, and an outer edge, an arc edge and an inner edge are sequentially formed on the main cutting edge along the direction from the outer side to the inner side of the drill body, the groove surface of the chip groove is a rake face, and the end surface of the first step is a first flank face. The main cutting edge is formed at the intersection of one side of the rake face and the first flank face, and the rear edge is formed at the intersection of the other side of the rake face and the first flank face;

[0009] The first rear blade surface is provided with an arc groove, and the arc groove is located on the rear edge.

[0010] When the tower-type step drill bit proposed by the utility model is used, during the process of drilling a workpiece at the cutting portion of the first step, the side tip formed between the outer blade and the arc blade is used to assist the drill core tip of the first step to contact the surface of the workpiece being drilled, which helps to maintain the stability of the drill body and reduce the radial deviation of the drill bit during the drilling process. During the drilling process, the arc groove located on the rear edge reduces the friction between the first step and the contact surface of the workpiece, further reducing the cutting resistance, so that the drill bit does not need to reduce the rotation speed when drilling the first step hole, thereby improving the cutting speed and drilling efficiency.

[0011] Compared with the prior art, the tower-type step drill provided by the utility model has the following substantial characteristics and progress: the tower-type step drill is provided with a crescent groove on the main cutting edge of the cutting portion of the first step, so that an outer blade, an arc blade and an inner blade are formed on the main cutting edge in sequence along the direction from the outside to the inside of the drill body; as the drilling process advances, the two inner blades and the arc blade begin to cut into the material, further expanding the diameter of the drill hole and beginning to form the hole wall; the arc blade is conducive to forming a smooth hole wall; the outer blade is used to remove more material and ensure the processing size, which is conducive to optimizing the formation of chips, facilitating smooth chip removal, helping to maintain the stability of the drill body, reducing the radial deviation of the drill bit during the drilling process, thereby improving the center positioning ability of the drill body, reducing the swing during drilling, and improving the drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of a tower-shaped step drill bit in an embodiment of the utility model.

[0013] Figure 2 yes Figure 1 Schematic diagram of the local enlarged structure at point A in the middle.

[0014] Figure 3 It is a marked schematic diagram of the first step of a tower-shaped step drill bit in an embodiment of the utility model.

[0015] Figure numerals: 1, handle; 2, drill body; 3, chip groove; 4, first step; 5, annular groove; 6, top angle tip; 7, side tip; 41, crescent groove; 42, outer blade; 43, arc blade; 44, inner blade; 45, arc groove. DETAILED DESCRIPTION

[0016] The specific implementation of the utility model is described in detail below with reference to the accompanying drawings.

[0017] like Figure 1-Figure 3As shown, a tower-shaped step drill bit is proposed in the embodiment of the utility model, aiming to improve the center positioning ability of the drill bit, reduce the swing during drilling, and improve the drilling efficiency.

[0018] A tower-type step drill bit proposed in the embodiment of the utility model is provided with a crescent groove 41 on the main cutting edge of the cutting portion of the first step 4, so that the main cutting edge is formed with an outer blade 42, a circular arc blade 43 and an inner blade 44 in sequence along the direction from the outside to the inside of the drill body 2. As the drilling process progresses, the two inner blades 44 and the circular arc blade 43 begin to cut into the material, further expanding the diameter of the drill hole and beginning to form the hole wall. The circular arc blade 43 is conducive to forming a smooth hole wall, and the outer blade 42 is used to remove more material and ensure the processing size, which is conducive to optimizing the formation of chips, facilitating smooth chip removal, helping to maintain the stability of the drill body 2, reducing the radial deviation of the drill bit during the drilling process, thereby improving the center positioning ability of the drill body 2, reducing the swing during drilling, and improving the drilling efficiency.

[0019] like Figure 1 As shown, the tower-type step drill bit comprises a handle 1 and a drill body 2 connected in one piece. The drill body 2 is composed of a plurality of steps arranged step by step, and a cutting portion is arranged on each step. A chip removal groove 3 is arranged on the side wall of the drill body 2. For example, Figure 1 As shown, 10 steps are arranged step by step on the drill body 2, and the diameters of the 10 steps decrease step by step toward the tip of the drill body 2. The number of steps on the drill body 2 is designed accordingly according to processing requirements, and the number of steps is preferably 6-12. The diameter of each step is selected according to the actual processing requirements.

[0020] like Figure 1 As shown, the handle body 1 is in the shape of a hexagonal prism, and an annular groove 5 is provided on the side wall of the handle body 1. In this way, the handle body 1 is convenient for centering and transmitting torque during the clamping process. The annular groove 5 is used to axially locate the handle body 1, which is conducive to the power tool to quickly clamp the handle body 1. For example, the chip removal groove 3 is a spiral groove.

[0021] like Figure 2 As shown, a crescent groove 41 is provided on the main cutting edge of the cutting portion of the first step 4 located at the tip of the drill body 2. An outer edge 42, a circular arc edge 43 and an inner edge 44 are formed on the main cutting edge in sequence from the outer side to the inner side of the drill body 2. The groove surface of the chip groove 3 is the rake face. The end face of the first step 4 is the first back face. The main cutting edge is formed at the intersection of one side of the rake face and the first back face. The back edge is formed at the intersection of the other side of the rake face and the first back face. A circular arc groove 45 is provided on the first back face, and the circular arc groove 45 is located on the back edge.

[0022] In order to make the arc groove 45 better suitable for the first step 4 of different structural sizes, the radius of the arc groove 45 is also related to the diameter of the first step 4. The radius of the arc groove 45 is r, the diameter of the first step 4 starts from 3 mm, r is 1 mm, and r increases by 0.25 mm for every 0.8 mm increase in the diameter of the first step 4.

[0023] like Figure 3 As described above, the vertical distance value from the top angle tip 6 of the inner blade 44 to the starting point of the arc groove 45 is defined as L. In order to be applicable to the back face sharpening of the first step 4 of different structural sizes, the sharpening starting point position of the arc groove 45 is related to the diameter of the first step 4. When the diameter of the first step 4 is less than or equal to 6mm, the distance value L is 1.05 times the diameter of the first step 4; when the diameter of the first step 4 is greater than 6mm, the distance value L is 1.35 times the diameter of the first step 3.

[0024] like Figure 3 As shown, a side tip 7 is provided between the outer blade 42 and the arc blade 43, and the vertical distance between the top angle tip 6 of the inner blade 44 and the side tip 7 in the diameter direction of the first step 4 is a, and the ratio of the distance value a to the diameter of the first step 4 is 0.3-0.4. The vertical distance between the top angle tip 6 of the inner blade 44 and the side tip 7 in the axial direction of the first step 4 is b, and the ratio of the distance value b to the diameter of the first step 4 is 0.08-0.13. In this way, the position of the side tip 7 on the main cutting edge is determined by the distance values ​​a and b, which is beneficial to provide auxiliary positioning for the grinding of the crescent groove 41, and further reduces the difficulty of grinding the arc blade 43.

[0025] When a tower-type step drill bit proposed in the embodiment of the utility model is used, during the process of drilling a workpiece at the cutting portion of the first step 4, the side tip 7 formed between the outer blade 42 and the arc blade 43 is used to assist the drill core tip of the first step 4 to contact the surface of the workpiece being drilled, which helps to maintain the stability of the drill body 2 and reduce the radial deviation of the drill bit during the drilling process. During the drilling process, the arc groove 45 located on the rear edge reduces the friction between the first step 4 and the contact surface of the workpiece, further reducing the cutting resistance, so that the drill bit does not need to reduce the rotation speed when drilling the hole in the first step 4, thereby improving the cutting speed and drilling efficiency.

[0026] Compared with conventional step drills, a tower-shaped step drill proposed in the embodiment of the utility model has a crescent groove 41 added to the main cutting edge of the first step 4, and a grinding structure of a circular arc groove 45 is provided on the rear edge, which greatly reduces the swing of the drill during high-speed cutting, and the holes drilled by the drill are more round. In particular, compared with conventional step drills with double back angles of 118 or 135 degrees on the head, the centering efficiency of the tower-shaped step drill is increased by 50%, and the efficiency of drilling holes in the first step 4 is increased by 30%.

Claims

1. A tower-type step drill, comprising a handle and a drill body connected in one piece, the drill body being composed of a plurality of steps arranged step by step, each step being provided with a cutting portion, and a chip removal groove being provided on the side wall of the drill body, characterized in that: A crescent groove is arranged on the main cutting edge of the cutting portion of the first step located at the tip of the drill body, and an outer edge, an arc edge and an inner edge are sequentially formed on the main cutting edge along the direction from the outer side to the inner side of the drill body, the groove surface of the chip groove is a rake face, and the end surface of the first step is a first flank face. The main cutting edge is formed at the intersection of one side of the rake face and the first flank face, and the rear edge is formed at the intersection of the other side of the rake face and the first flank face; The first rear blade surface is provided with an arc groove, and the arc groove is located on the rear edge.

2. The tower-type step drill bit according to claim 1, characterized in that: The radius of the arc groove is r, the diameter of the first step starts from 3 mm, r is 1 mm, and r increases by 0.25 mm every time the diameter of the first step increases by 0.8 mm.

3. The tower-type step drill bit according to claim 2, characterized in that: The vertical distance from the top angle tip of the inner blade to the starting point of the arc groove is defined as L; When the diameter of the first step is less than or equal to 6 mm, the distance value L is 1.05 times the diameter of the first step; When the diameter of the first step is greater than 6 mm, the distance value L is 1.35 times the diameter of the first step.

4. The tower-type step drill bit according to claim 1, characterized in that: A side tip is provided between the outer blade and the arc blade, a vertical distance between the top angle tip of the inner blade and the side tip in the diameter direction of the first step is a, and a ratio of the distance value a to the diameter of the first step is 0.3-0.

4.

5. The tower-type step drill bit according to claim 4, characterized in that: The vertical distance between the top angle tip and the side tip of the inner edge in the axial direction of the first step is b, and the ratio of the distance value b to the diameter of the first step is 0.08-0.

13.

6. The tower-type step drill bit according to claim 1, characterized in that: The handle body is in the shape of a hexagonal prism, and an annular groove is arranged on the side wall of the handle body.

7. The tower-type step drill bit according to claim 1, characterized in that: The chip removal groove is a spiral groove.

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