A through-hole drill

Abstract

The through-hole drilling drill provided by this utility model includes a drill bit, a drill body, and a drill shank. The drill body consists of a flaring and flanging section, a hole diameter determining section, and a smoothing section from bottom to top. The flaring and flanging section contains at least one flaring helical tooth. From bottom to top, the helical radius of the flaring helical tooth gradually increases. Its minimum helical radius is called the initial helical radius, and its maximum helical radius is called the final helical radius. The hole diameter determining section contains at least one hole diameter helical tooth, and its helical radius is equal to the final helical radius. The drill bit radius is smaller than the final helical radius. In use, the drill bit first makes a hole, and then the helical feed of the flaring helical tooth and the hole diameter helical tooth forces the edge of the hole to form a flang, thus completing the hole drilling. It can not only perform hole drilling operations on bent pipes, but also ensure that the flang is only on the outside of the pipe. It also simplifies the overall structure of the drilling drill and improves the stability of use.

Description

Technical Field

[0001] This utility model belongs to the field of hole-pulling technology, specifically relating to a through-hole-pulling drill. Background Technology

[0002] To facilitate pipe connection, it is common practice in various industries to make a hole in the side wall of the main pipe, insert another branch pipe into the hole, and then seal the branch pipe to the main pipe by welding or other means. If the wall thickness of the main pipe is thin, it is necessary to make the hole have a certain height of flange to increase the sealing area. This process of making the hole have a certain height of flange is known in the industry as "hole pulling".

[0003] Common hole-pulling methods can be broadly categorized into three types. The first type uses a mold to push the edge of the hole in the main pipe sidewall outwards. For example, Chinese patent CN204470382U discloses a digitally controlled automatic copper pipe hole-pulling machine. This machine uses a copper pipe positioning rod to send the hole-pulling mold into the main pipe, and then uses a hole-pulling connecting rod to drive the mold up and down to achieve hole pulling. This method is complex, involves many steps, and is inefficient. Because the copper pipe positioning rod cannot easily pass through the curved parts of the main pipe, it cannot perform hole pulling operations on the curved parts of the main pipe, thus limiting its application. The second type uses thermal melting for hole pulling. For example, Chinese patent CN113199065A discloses a thermal melting drill and its application. During operation, the high-speed rotation and axial feed of the thermal melting drill create a small hole in the sidewall of the main pipe. Then, the conical polyhedron on the thermal melting drill presses the edge of the small hole, causing the metal at the edge of the small hole to red-hot and soften through frictional heating, and then being squeezed outwards until... The conical polyhedron penetrates the entire pipe wall to complete the thermal fusion drilling. The creep and even molten material formed in this way is distributed on both the outside and inside of the main pipe. This not only forms a flange on the outside of the main pipe but also on the inside, thereby increasing the fluid flow resistance inside the main pipe. At the same time, the high speed and high temperature requirements also place high demands on the characteristics of the thermal fusion drill itself, making it difficult to process. Another type involves first drilling into the main pipe by feeding the drill bit, then extending a fusion needle that is obliquely inserted into the drill bit, and then feeding the drill bit in the opposite direction. The fusion needle is used to flip up the edge of the drilled hole to form a flange. For example, Chinese patent CN211490436U discloses this type of drilling and fusion head. However, this solution requires opening an oblique insertion hole in the drill bit and setting up structures such as a sliding sleeve, sliding groove, drive device, and power device on the drill bit, making the overall structure of the drilling and fusion head more complex, with more parts, and making it difficult to guarantee stability during use. Utility Model Content

[0004] The purpose of this invention is to overcome one or more shortcomings in the prior art and to provide a through-hole drilling drill and a method for drilling holes in pipe fittings.

[0005] To achieve the above objectives, the product in this utility model is a through-hole drill, comprising a drill bit, a drill body, and a drill shank coaxially arranged from bottom to top along the direction of drilling into the pipe. The drill body, from bottom to top, consists of a flaring and flange section, a diameter-determining section, and a smoothing section. The flaring and flange section contains at least one flaring helical tooth. The distance from the vertex of the flaring helical tooth to the centerline of the drill is called the helical radius at that point. From bottom to top, the helical radius of the flaring helical tooth gradually increases, with the smallest radius called the initial helical radius and the largest radius called the final helical radius. The diameter-determining section contains at least one diameter helical tooth, and the helical radius at the vertex of the diameter helical tooth remains unchanged and is equal to the final helical radius of the flaring helical tooth. Obviously, the radius of the drill bit is smaller than the final helical radius of the flaring helical tooth. The drill bit can be a dovetail-type hole-opening cutter, a milling cutter, or a twist drill.

[0006] In the above scheme, the principle of the helical teeth turning the edge of the hole in the side wall of the main pipe upward and outward can be explained using bolts and nuts:

[0007] If a nut is screwed onto a right-hand threaded bolt with the bolt head facing down, and the nut is allowed to move up and down but not rotate, when we turn the bolt head counterclockwise, the thread exerts an upward force on the nut, causing it to move upward, and we observe the thread rising one turn at a time. When we turn the bolt head clockwise, the thread exerts a downward force on the nut, causing it to move downward, and we observe the thread sinking one turn at a time. The direction of the force exerted by the thread on the nut is the normal direction to the upper or lower tooth surface of the thread.

[0008] The flared helical teeth of this invention resemble bolt threads, with a gradually increasing helical radius. When the flared helical teeth are raised upwards, they exert an upward and outward force on the edge of the hole in the pipe wall (the direction of the force is the same as the normal direction of the upper tooth surface of the helical teeth at that location), causing the edge of the hole to flare upwards and outwards. When the flared helical teeth are lowered downwards, they exert a downward and outward force on the edge of the hole in the pipe wall (the direction of the force is the same as the normal direction of the lower tooth surface of the helical teeth at that location), causing the edge of the hole to flare downwards and outwards.

[0009] Preferably, the highest point of the flared helical tooth is located on the side of the same frustum, the radius of the lower end of the frustum is equal to the initial helical radius of the flared helical tooth, and the radius of the upper end of the frustum is equal to the final helical radius of the flared helical tooth. The frustum is a truncated cone, an ellipsoidal frustum, or a parabolic frustum; the cross-sectional lines on both sides of the longitudinal section of the truncated cone, the ellipsoidal frustum, or the parabolic frustum are a straight line, an elliptical curve, and a parabolic curve, respectively.

[0010] Preferably, the tooth tip profile of the flared spiral tooth is a curve, the angle between the upper tooth surface profile of the flared spiral tooth and the axis of the drill body is less than or equal to 90° and is tangent to the tooth tip profile, and the angle between the lower tooth surface profile of the flared spiral tooth and the axis of the drill body is less than or equal to 90° and is tangent to the tooth tip profile.

[0011] Preferably, the flared helical teeth are right-handed helical teeth.

[0012] Preferably, the lower end of the aperture helical tooth is smoothly connected to the upper end of the flared helical tooth.

[0013] Preferably, the number of the aperture helical teeth is not less than the number of the flared helical teeth.

[0014] Preferably, the tooth tip profile of the borehole spiral tooth is a curve, the angle between the upper tooth surface profile of the borehole spiral tooth and the axis of the drill body is less than or equal to 90° and is tangent to the tooth tip profile, and the angle between the lower tooth surface profile of the borehole spiral tooth and the axis of the drill body is less than or equal to 90° and is tangent to the tooth tip profile.

[0015] Preferably, the radius of the drill bit is equal to or slightly larger than the initial helical radius of the flared helical teeth.

[0016] To achieve the above objectives, the method employed in this invention is a pipe drilling method, implemented using any one of the above-described through-hole drilling methods, comprising the following steps:

[0017] S1. Fix the pipe fitting to be drilled below the through-hole drill;

[0018] S2. Rotate the through-hole drill and feed it downwards, while ensuring that the flaring helical teeth rise upwards, until the drill bit of the through-hole drill completely penetrates the upper pipe wall of the fitting, forming a hole in the upper pipe wall.

[0019] S3. Continue feeding downwards in the current rotation direction, while ensuring that the flared helical teeth are raised upwards;

[0020] S4. Continue to feed downwards, so that the flared helical teeth gradually enter the upper pipe wall hole, and drive the edge of the upper pipe wall hole to turn upwards and outwards until the flared section of the through-hole drill body completely penetrates the upper pipe wall hole.

[0021] S5. Continue to feed downwards, so that the diameter helical teeth gradually enter the upper pipe wall hole, causing the edge of the upper pipe wall hole to turn upwards and outwards and shaping all the turns, until the diameter-determined section of the through-hole drill body completely penetrates the upper pipe wall hole, completing the hole-pulling operation of the upper pipe wall hole. The through-hole drill continues to rotate and feed in the current direction.

[0022] S6. Continue until the drill bit of the through-hole drill completely penetrates the lower pipe wall of the pipe to be drilled, forming a hole in the lower pipe wall.

[0023] S7. After forming the lower pipe wall hole, stop rotating for a period of time, and then rotate in the opposite direction. At this time, no matter how large or small the downward feed speed is, the flared spiral teeth on the drill body of the through-hole drilling machine will always sink downward, then proceed to the next step.

[0024] S8. Continue feeding downwards. The flared helical teeth continue to sink downwards. The flared helical teeth gradually enter the lower pipe wall hole and drive the edge of the lower pipe wall hole to turn downwards and outwards until the flared section on the drill body of the through-hole drill completely penetrates the lower pipe wall hole.

[0025] S9. Continue feeding downwards. The flared helical teeth continue to sink downwards, allowing the diameter helical teeth to gradually enter the lower pipe wall hole. This causes the edge of the lower pipe wall hole to turn downwards and outwards, and the turned edge is shaped until the diameter-determined section of the through-hole drilling body completely penetrates the lower pipe wall hole, completing the hole-pulling operation of the lower pipe wall hole.

[0026] S10. Retract the through-hole drill to the initial position to obtain a pipe fitting with a through hole.

[0027] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:

[0028] The through-hole drilling drill provided by this utility model includes a drill bit, a drill body, and a drill shank coaxially arranged from bottom to top along the direction of drilling into the pipe. The drill body consists of a flaring section, a diameter-determining section, and a smoothing section from bottom to top. The flaring section contains at least one flaring helical tooth, and the helical radius of the flaring helical tooth gradually increases from bottom to top. The minimum helical radius of the flaring helical tooth is called the initial helical radius, and the maximum helical radius of the flaring helical tooth is called the final helical radius. The diameter-determining section contains at least one diameter helical tooth, and the helical radius of the diameter helical tooth is equal to the final helical radius. In use, the drill bit first drills a hole, and then the helical feed of the flaring helical tooth and the diameter helical tooth forces the edge of the hole to form a flange, thus completing the hole extraction. This method can not only perform hole extraction operations on bent pipes, expanding its application range, but also ensures that the flange formed by hole extraction exists only on the outside of the pipe, without increasing the fluid flow resistance inside the pipe. It also simplifies the overall structure of the drilling drill and improves its stability during use. The pipe extraction method provided by this utility model is simple in steps, convenient in operation, and highly efficient in drilling and extraction. Attached Figure Description

[0029] Figure 1 This is a front view schematic diagram of a preferred embodiment of the through-hole drill of this utility model.

[0030] Figure 2 for Figure 1A longitudinal section diagram of the frustum containing the highest point of the tooth tip of the flared spiral tooth shows the longitudinal section lines of three different frustums.

[0031] Figure 3 for Figure 1 Enlarged cross-sectional view of point A along the central axis.

[0032] Figure 4 for Figure 1 A simplified diagram of the drill bit and drill body.

[0033] Figures 5 to 8 for Figure 1 A schematic diagram illustrating the drilling and extraction process using a through-hole drill. Figure 5 This is a schematic diagram showing the drill bit feeding downwards and contacting the outer wall of the pipe fitting. Figure 6 This is a schematic diagram of the drill bit completing the drilling process. Figure 7 This is a schematic diagram showing how the flared spiral tooth feed forces the edge of the hole to form a flange. Figure 8 This is a schematic diagram of a helical feed solidification and flanging process using a helical tooth for aperture diameter.

[0034] Figure 9 for Figure 7 A schematic diagram of the forces acting at the edge of the central hole.

[0035] Figure 10 for Figure 8 The diagram shows the through-hole drill continuing to feed downwards, completing the drilling and extraction of the hole in the lower wall of the pipe fitting.

[0036] Figure 11 for Figure 1 A schematic diagram of a through-hole drill extruding an initial notch at the edge of the hole.

[0037] Figure 12 for Figure 1 A schematic diagram of the notch at the edge of the hole after a half-turn flaring of a flaring spiral tooth in a through-hole drill.

[0038] Figure 13 for Figure 1 A schematic diagram of the hole edge after the through-hole drilling is completed.

[0039] Figure 14 for Figure 1 A schematic diagram of the flaring process in another embodiment of a through-hole drill.

[0040] Wherein: 1. Pipe fitting; 2. Upper pipe wall; 3. Hole; 4. Flanged edge; 5. Upper pipe wall hole; 6. Initial notch; 7. Hole notch; 8. Lower pipe wall; 9. Lower pipe wall hole; 10. Drill bit; 20. Drill body; 21. Flared section; 211. Flared helical tooth; 212. Tooth tip; 213. Upper tooth surface; 214. Lower tooth surface; 22. Hole diameter determination section; 221. Hole diameter helical tooth; 222. Tooth tip; 223. Upper tooth surface; 224. Lower tooth surface; 23. Smooth section; 30. Drill shank; F. Resultant force diagonally upward; F1. Vertically upward component force; F2. Horizontal leftward component force; The curve with arrows indicates the direction of rotation. Detailed Implementation

[0041] Example 1

[0042] like Figure 1 , 3 As shown in Figure 4, the through-hole drill provided by this utility model includes a drill bit 10, a drill body 20, and a drill shank 30 arranged coaxially from bottom to top along the direction of drilling into the pipe fitting 1. The drill body 20 consists of a flared and flanged section 21, a hole diameter determining section 22, and a smooth section 23 from bottom to top. The flared and flanged section 21 includes a flared helical tooth 211, which spirals twice. The flared helical tooth 211 is a right-handed helical tooth. From bottom to top, the helical radius of the flared helical tooth 211 gradually increases. The minimum helical radius of the flared helical tooth 211 is called the initial helical radius. The maximum helical radius is called the terminal helical radius. The aperture determining section 22 includes an aperture helical tooth 221. The aperture helical tooth 221 helices two and a half turns. The direction of rotation of the aperture helical tooth 221 is the same as that of the flared helical tooth 211, and it is also a right-hand helical tooth. The helical radius of the aperture helical tooth 221 is equal to the terminal helical radius. The lower end of the aperture helical tooth 221 is smoothly connected to the upper end of the flared helical tooth 211. This smooth connection means that the contour surfaces of the aperture helical tooth 221 and the flared helical tooth 211 are aligned and connected, and the connection is smooth and flat without bumps. The drill bit 10 is a dovetail or right-hand twist drill bit.

[0043] When using, such as Figures 5 to 8As shown, the through-hole drill rotates and feeds downwards. The drill bit 10 first drills a hole 3 in the upper wall 2 of the pipe fitting 1. Then, through the spiral feed of the flaring helical teeth 211 and the hole diameter helical teeth 221, the edge of the hole 3 is forced to turn upwards and outwards to form a flange 4, thus completing the hole extraction. This through-hole drill can not only perform hole extraction operations on bent pipe fittings, thus having a wider range of applications, but also ensures that the flange 4 formed by the hole extraction exists only on the outside of the pipe fitting 1, without increasing the fluid flow resistance inside the pipe fitting 1. Furthermore, it simplifies the overall structure of the through-hole drill and improves its performance. Stability during use; by making the flared spiral teeth 211 and the bore diameter spiral teeth 221 smoothly connected, there are no gaps between the flared spiral teeth 211 and the bore diameter spiral teeth 221, which can also avoid scratching the inner wall of the flange 4, thereby eliminating potential problems during subsequent assembly and use; since most machine tool drills are designed clockwise, setting the flared spiral teeth 211 and the bore diameter spiral teeth 221 to right-hand spiral teeth can also make it easy to install the through-hole drill into existing machine tools to complete the hole-pulling operation.

[0044] like Figure 2 As shown, in this embodiment, the highest point of the tooth tip 212 of the flared helical tooth 211 is located on the side of the same frustum. The side of the frustum is formed by rotating its generatrix around the axis of the drill body 20. The generatrix is ​​a straight line and gradually approaches the axis of the drill body 20 from top to bottom, making the frustum larger at the top and smaller at the bottom. The initial helical radius is equal to the radius Rx at the lower end of the frustum, and the final helical radius is equal to the radius Rd at the upper end of the frustum. In other embodiments, the generatrix of the frustum can also be a curve, such as an elliptical arc or a parabola, making the frustum an ellipsoidal frustum or a parabolic frustum.

[0045] The tooth tip 212 of the flared spiral tooth 211 has a curved profile. Preferably, the angle between the upper tooth surface 213 of the flared spiral tooth 211 and the axis of the drill body 20 is less than or equal to 90° and is tangent to the tooth tip profile. In this embodiment, the angle is 30°. Preferably, the angle between the lower tooth surface 214 of the flared spiral tooth 211 and the axis of the drill body 20 is less than or equal to 90° and is tangent to the tooth tip profile. In this embodiment, the angle is also 30°.

[0046] Furthermore, the profile line of the tooth tip 222 of the borehole spiral tooth 221 is a curve. Preferably, the angle between the profile line of the upper tooth surface 223 of the borehole spiral tooth 221 and the axis of the drill body 20 is less than or equal to 90° and is tangent to the profile line of the tooth tip. In this embodiment, the angle is 30°. Preferably, the angle between the profile line of the lower tooth surface 224 of the borehole spiral tooth 221 and the axis of the drill body 20 is less than or equal to 90° and is tangent to the profile line of the tooth tip. In this embodiment, the angle is also 30°.

[0047] In this embodiment, the number of bore diameter helical teeth 221 and flared helical teeth 211 is one. In other embodiments, the number of bore diameter helical teeth 221 and flared helical teeth 211 can also be two or three, as long as the number of bore diameter helical teeth 221 is not less than the number of flared helical teeth 211 and all helical teeth are evenly distributed on the side of the drill body 20. When the number of bore diameter helical teeth 221 is more than the number of flared helical teeth 211, the extra bore diameter helical teeth 221 cannot be smoothly connected with the flared helical teeth 211, and the lower ends of these bore diameter helical teeth 221 are not connected. Specifically, when the number of bore diameter helical teeth 221 is more than the number of flared helical teeth 211, all bore diameter helical teeth 221 are divided into two parts, one of which has a number of bore diameter helical teeth 221 equal to the number of flared helical teeth 211. The number of flared spiral teeth 211 is equal. The diameter spiral teeth 221 in this part correspond one-to-one with the flared spiral teeth 211 and are smoothly connected (tooth tip 212 is smoothly connected to tooth tip 222, upper tooth surface 213 is smoothly connected to upper tooth surface 223, and lower tooth surface 214 is smoothly connected to lower tooth surface 224). Multiple spiral structures with equal angles are formed on the entire drill body 20. Each of the other part of the diameter spiral teeth 221 is set in the interval between two adjacent spiral structures. This design can provide more sufficient support for the flange 4 through the two parts of the diameter spiral teeth 221 when the diameter determining part 22 moves to the position of the flange 4, and avoid the flange 4 from shrinking inward and getting stuck in the tooth groove of the diameter spiral teeth 221 or the flange 4 twisting and getting stuck in the diameter spiral teeth 221.

[0048] In this embodiment, the radius of the drill bit 10 is equal to the initial helical radius Rx; the helix angle of the flared helical teeth 211 is the same as the helix angle of the bore diameter helical teeth 221, so as to facilitate machining.

[0049] The through-hole drilling drill provided by this utility model can perform through-hole drilling and piercing on bent pipes, as well as on straight pipes, making it widely applicable. During drilling, there is no need to rotate the pipe, eliminating the need for a servo motor. It is also easy to clamp and use on existing machine tools. At the same time, the through-hole drilling drill has a relatively low operating speed, low operating temperature, and long service life. Furthermore, the final flange is located on the outside of the pipe, with no flange inside the pipe cavity, thus not increasing the flow resistance inside the pipe cavity.

[0050] It should be noted that the through-hole drill is made of a high-hardness alloy, such as tungsten carbide alloy. The drill shank 30 has a prismatic structure to facilitate heat dissipation. The drill shank 30 is used to connect to a handheld drill or to be clamped onto a machine tool. Its diameter can be set as needed and can be the same as or different from the diameter of the drill body 20. The drill bit 10 is a dovetail-groove type opening cutter (e.g., Figure 1 As shown), it can also be a milling cutter head or a twist drill bit. When the handheld drill or machine tool drives the through-hole drill to rotate, it can also drive the through-hole drill to feed axially.

[0051] It should be noted that the flared helical teeth 211 and the bore diameter helical teeth 221 must be attached to a certain physical structure, such as a cylindrical core with radius R. These helical teeth are fixedly connected to the cylindrical core or machined into one piece. The tooth height of the bore diameter helical teeth is Rd-R. The drill bit 10 is fixedly connected to the cylindrical core or machined into one piece. The length of the drill bit 10 is greater than or equal to the wall thickness of the pipe fitting 1 to be drilled, preferably exceeding the wall thickness of the pipe fitting 1 to be drilled by 2mm.

[0052] The length of the aperture determining section 22 is greater than the height of the flange 4 required for hole extraction. That is, the aperture helical teeth 221 on the aperture determining section 22 are extended into the flange 4. Provided that the uppermost end of the aperture helical teeth 221 is higher than the flange 4, the lowermost end of the aperture helical teeth 221 should be lower than the lowest point of the flange 4. The length of the flared flange section 21 should be considered together with the aperture determining section 22. Specifically, the sum of the lengths of the flared flange section 21 and the aperture determining section 22 should be less than the inner diameter of the pipe fitting 1 to be extracted, to avoid interference when extracting holes at the upper and lower ends of the pipe fitting 1. Specifically, during the flaring of the lower pipe wall by the flaring helical teeth, the flaring helical teeth exert a downward force on the edge of the hole in the lower pipe wall. The aperture helical teeth all sink downwards. If the aperture helical teeth are still in contact with the upper pipe wall, they also exert a downward force on the edge of the hole in the pipe wall, which is undesirable. These lengths can be designed with a certain margin.

[0053] This utility model also provides a method for extracting holes in pipe fittings, which is achieved using the aforementioned through-hole drilling tool, such as... Figures 5 to 8 and Figure 10 As shown, the pipe fitting extraction method includes the following steps:

[0054] S1. Fix the pipe fitting 1 to be drilled below the through-hole drill;

[0055] S2. Rotate the through-hole drill to the right and feed it downwards, but the helical teeth are still raised until the drill bit 10 of the through-hole drill completely penetrates the upper pipe wall of the pipe fitting 1, forming the upper pipe wall hole 5.

[0056] S3. Continue to feed downwards, so that the flared helical teeth 211 gradually enter the upper pipe wall hole 5, and drive the edge of the upper pipe wall hole 5 to turn upwards and outwards until the flared section 21 on the drill body 20 of the through-hole drill completely penetrates the upper pipe wall hole 5.

[0057] Specifically, in the initial stage, the lowermost end of the flared spiral teeth 211 enters the upper tube wall hole 5. Through spiral compression, the edge of the upper tube wall hole 5 is turned upward and outward. At this time, the force is as follows: Figure 9 As shown, and to form a small initial notch 6 at the edge of the upper pipe wall hole 5, as... Figure 11As shown; as the through-hole drill continues to feed downwards, the tooth tip 212 of the subsequent flared helical tooth 211 immediately embeds into the initial notch 6 and applies an upward oblique force to the initial notch 6 and its adjacent parts, causing the initial notch 6 to gradually increase in size, forming a hole notch 7, as shown. Figure 12 As shown; until the uppermost flared spiral teeth 211 spirally squeeze the edge of the upper tube wall hole 5, at this time, the hole notch 7 does not cover the 360° range;

[0058] S4. Continue to feed downwards, so that the diameter helical teeth 221 gradually enter the upper pipe wall hole 5, causing the edge of the upper pipe wall hole 5 to turn upwards and outwards and shaping all the turned edges 4, until the diameter determination section 22 on the drill body 20 of the through hole drilling drill completely penetrates the upper pipe wall hole 5, and the hole drilling operation of the upper pipe wall hole 5 is completed.

[0059] Specifically, in the initial stage, the lowermost edge of the aperture helical tooth 221... Figure 12 The hole 7 in the drill bit enters the upper pipe wall hole 5. As the through-hole drill rotates and feeds downward, the helical teeth 221 of the borehole diameter spirally compress the edge of the upper pipe wall hole 5, forcing it to turn upward and outward. When the rotation angle of the helical teeth 221 reaches 360°, a flange 4 is formed around the perimeter. Figure 13 As shown, when feeding continues, since the helical radius of the subsequent bore diameter helical tooth 221 is equal to the inner diameter of the flange 4, the subsequent bore diameter helical tooth 221 will not squeeze the edge of the upper pipe wall hole 5 and the flange 4, but only play the role of keeping the flange 4 stable. Obviously, in the single hole pulling process, the flaring helical tooth 211 does not complete the flange 4 in a 360° range, but the flange 4 in a 360° range is completed by the lowest section of the bore diameter helical tooth 221.

[0060] S5. After the flange of the upper pipe wall hole 5 has completely cooled and solidified, rotate the through hole drill to the right and feed it downward until the drill bit 10 of the through hole drill completely penetrates the lower pipe wall 8 of the pipe fitting to be pulled, forming the lower pipe wall hole 9.

[0061] S6. Reverse the through-hole drill and continue to feed downwards. At this time, no matter how much the downward feed speed is, the spiral teeth sink downwards, so that the flared spiral teeth 221 gradually enter the lower pipe wall hole 9, and drive the edge of the lower pipe wall hole 9 to turn downwards and outwards until the flared section 21 on the drill body 20 of the through-hole drill completely penetrates the lower pipe wall hole 9.

[0062] S7. Continue to feed downwards, so that the diameter helical teeth 221 gradually enter the lower pipe wall hole 9, and shape the downward and outward flanges 4 of the lower pipe wall hole 9 until the diameter determination section 22 on the drill body 20 of the through hole drilling drill completely penetrates the lower pipe wall hole 9, and the hole pulling operation of the lower pipe wall hole 9 is completed.

[0063] S8. Stop rotating and retract the through-hole drill to the initial position to obtain a pipe fitting with a through hole. The axis of the flange hole on the upper pipe wall 2 and the axis of the flange hole on the lower pipe wall 8 are on the same straight line.

[0064] The method for extracting holes in pipe fittings is simple, easy to operate, and highly efficient.

[0065] It should be noted that during the rotation of the through-hole drill, if the through-hole drill rotates at high speed, frictional heat will be generated when the flaring helical teeth and the borehole diameter helical teeth squeeze the edge of the hole, which will cause the temperature of the hole edge to rise, resulting in creep or even melting. In this utility model, the helical radius of the flaring helical teeth gradually increases from bottom to top, and it is a right-handed helical tooth. When the through-hole drill feeds downward, the flaring helical teeth still rise upward and cause the creeping or even melting hole edge to turn upward and outward. The formed flange is entirely outside the tube. When the borehole diameter helical teeth pass through this flange, the borehole diameter helical teeth also rise upward. The lowest small section of the borehole diameter helical teeth causes the creeping or even melting hole edge to turn upward and outward. The subsequent borehole diameter helical teeth have no friction or slight friction on the flange. Even if slight friction generates slight heat, it is less than the heat dissipation. The temperature of the flange decreases and it gradually solidifies. The subsequent part of the borehole diameter helical teeth completes the shaping of the flange.

[0066] Example 2

[0067] The through-hole drill in Example 2 is basically the same as that in Example 1, except that in Example 2, there are two caliber helical teeth on the drill body, and these two teeth are evenly spaced. One of them is smoothly connected to the flared helical teeth. At the lower end of the caliber helical teeth, along the... Figure 12 After the hole 7 in the middle enters the hole 5 in the upper pipe wall, it only needs to be rotated 180° to form a flange 4 with a range of 360°.

[0068] Example 3

[0069] The through-hole drilled in Example 3 is basically the same as in Example 2, except that in Example 3, there are two flared helical teeth on the drill body, namely front tooth A and rear tooth B. The position of front tooth A is 90° ahead of rear tooth B, forming a hole when entering the pipe wall. Figure 11 When the "initial gap" is in the middle, such as Figure 14 As shown, the front tooth A starts drilling at position A1 and the rear tooth B starts drilling at position B1. When the through-hole drilling drill rotates another 90° and feeds axially, the front tooth A flares out to position A2 and the rear tooth B flares out to position B2. When the through-hole drilling drill continues to rotate and feed axially, the front tooth A flares out to position A3 and the rear tooth B flares out to position B3. Obviously, the subsequent flaring of the rear tooth B is all based on the previous flaring of the front tooth A, that is, the flaring of the rear tooth at position B2 is based on the flaring of the front tooth at position A1.

[0070] The advantage of this design is that it reduces the amount of pressure exerted on the hole edge by each flaring spiral tooth each time, and the multiple progressive flaring processes help improve the quality of hole extraction.

[0071] Similarly, in other embodiments, three or four or more flaring spiral teeth can be provided, which can reduce the time required for flaring, reduce the amount of extrusion, and improve the quality of hole extraction.

[0072] The above are merely embodiments of this utility model. Those skilled in the art can make appropriate changes and improvements to this utility model without departing from its technical scope. The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand and implement the content of this utility model. They cannot be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A through-hole drill for drilling holes at the upper and lower ends of a pipe fitting, comprising a drill bit, a drill body, and a drill shank coaxially arranged from bottom to top along the drilling direction into the pipe fitting, wherein the drill body comprises, from bottom to top, a flaring section, a hole diameter defining section, and a smoothing section, characterized in that: The flared and flanged section contains at least one flared helical tooth. From bottom to top, the helical radius of the flared helical tooth gradually increases. The minimum helical radius of the flared helical tooth is called the initial helical radius, and the maximum helical radius of the flared helical tooth is called the final helical radius. The aperture determining section contains at least one aperture helical tooth. The helical radius of the aperture helical tooth is equal to the final helical radius of the flared helical tooth. The sum of the lengths of the flared and flanged section and the aperture determining section is less than the inner diameter of the pipe to be drilled. The diameter of the smooth section is less than the helical radius of the aperture helical tooth.

2. The through-hole drill according to claim 1, characterized in that: The highest point of the flared helical tooth is located on the side of the same frustum. The radius of the lower end of the frustum is equal to the initial helical radius of the flared helical tooth, and the radius of the upper end of the frustum is equal to the final helical radius of the flared helical tooth. The frustum is a truncated cone, an ellipsoidal frustum, or a parabolic frustum.

3. The through-hole drill according to claim 1, characterized in that: The tooth tip profile of the flared spiral tooth is a curve. The angle between the upper tooth surface profile of the flared spiral tooth and the axis of the drill body is less than or equal to 90° and is tangent to the tooth tip profile. The angle between the lower tooth surface profile of the flared spiral tooth and the axis of the drill body is less than or equal to 90° and is tangent to the tooth tip profile.

4. The through-hole drill according to claim 1, characterized in that: The flared helical teeth are right-handed helical teeth.

5. The through-hole drill according to claim 1, characterized in that: The lower end of the aperture helical tooth is smoothly connected to the upper end of the flared helical tooth.

6. The through-hole drill according to claim 1, characterized in that: The direction of rotation of the aperture helical teeth is the same as that of the flared helical teeth.

7. The through-hole drill according to claim 1, characterized in that: The number of the diameter spiral teeth is not less than the number of the flared spiral teeth.

8. The through-hole drill according to claim 1, characterized in that: The tooth tip profile of the borehole spiral tooth is a curve. The angle between the upper tooth surface profile of the borehole spiral tooth and the axis of the drill body is less than or equal to 90° and is tangent to the tooth tip profile. The angle between the lower tooth surface profile of the borehole spiral tooth and the axis of the drill body is less than or equal to 90° and is tangent to the tooth tip profile.

9. The through-hole drill according to claim 1, characterized in that: The radius of the drill bit is equal to or slightly larger than the initial helical radius of the flared helical teeth.

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