A core drill

Abstract

The utility model discloses a kind of hole pulling drills, including hole pulling drill head and drill body sequentially arranged from below to above along the drilling feeding direction, and both axis coincides, spiral tooth is arranged on the drill body, the spiral tooth includes first spiral tooth and second spiral tooth sequentially arranged from below to above along the periphery of drill body, flared section is formed on the drill body by the first spiral tooth, aperture determination section is formed on the drill body by the second spiral tooth, compared with prior art, the utility model is set by the force that spiral tooth is applied to hole edge from outside outward and upward, avoid the phenomenon that curved pipeline cannot be constructed when force is applied from inside to outside of hole during hole pulling;At the same time, first spiral tooth will directly lift hole edge, without making pipeline metal soften or melt, its processing difficulty is small, and the case that softened metal material is distributed in pipeline will not appear.

Description

Technical Field

[0001] This utility model relates to the technical field of hole-pulling on metal pipes, and specifically to a hole-pulling drill. Background Technology

[0002] Many industries require openings in the sidewalls of main pipelines to insert branch pipes, which are then sealed together using welding or other methods. If the sidewalls of the main pipeline are thin, the openings are sometimes flanged to increase the sealing area. This process of flanged openings is known in the industry as "hole extraction."

[0003] To increase the flange height of the opening, a representative example is patent document CN204470382U, which discloses a digitally controlled automatic copper tube drawing machine. During the drawing process, the necessary step for clamping the main tube is that the "copper tube positioning rod and drawing mold" described in the patent extend into the straight inner cavity of the main tube before subsequent drawing operations can be performed. This patented technology has the following drawbacks: First, it requires the main tube to be straight for drawing. For bent copper tubes, the "copper tube positioning rod and drawing mold" described in the patent cannot extend into the inner cavity of the bent copper tube, obviously making it impossible to draw holes in bent copper tubes. Second, the patent describes "using the drawing connecting rod to drive the drawing mold, causing the drawing cutter to use oblique cutting to drive the drawing core to move up and down, pushing it upward through the mold guide sleeve, thus drawing the copper tube outwards," indicating that when the patented solution is applied to drawing holes, it uses an inside-out force to flange the copper tube outwards.

[0004] Another method is thermal fusion drilling, as disclosed in patent document CN113199065A, which describes a thermal fusion drill and its application for drilling holes in straight and bent copper pipes. During operation, the thermal fusion drilling head rotates at high speed while simultaneously moving axially downwards. The cutting edge of the thermal fusion drilling head drills a small hole in the wall of the main pipe. Then, a conical polyhedron rubs against the edge of the small hole, generating heat and causing the metal at the edge of the hole to soften and glow red. The conical polyhedron pushes the molten metal outwards. The subsequent section enlarges and continues to rub against the edge of the small hole on the sidewall, further expanding the molten metal outwards until the conical polyhedron has completely penetrated the pipe wall. The flanges of the thermal fusion drilling are distributed on the inner and outer sides of the main pipe. The patented technology has the following drawbacks: ① The head of the hot-melt hole-drawing process needs to rotate at high speed. The friction between the hot-melt hole-drawing process and the edge of the small hole generates heat and the temperature rises. The temperature needs to reach the temperature at which the main pipe metal softens or even melts; ② Creeping or even melting material is distributed on the outside and inside of the main pipe, that is, there is also a flange on the inside of the main pipe, which increases the fluid flow resistance inside the main pipe.

[0005] Therefore, how to overcome the shortcomings of the existing technology mentioned above has become the subject of this utility model. Utility Model Content

[0006] This utility model provides a hole-pulling drill, which aims to solve the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a drilling drill, comprising a drilling head and a drill body arranged sequentially from bottom to top along the drilling feed direction, with their axes coinciding; the drill body is provided with helical teeth, the helical teeth including a first helical tooth and a second helical tooth arranged sequentially from bottom to top along the circumference of the drill body; the first helical tooth forms a flared section on the drill body, and the second helical tooth forms a hole diameter defining section on the drill body; the first helical tooth and the second helical tooth are smoothly connected along the axial direction by a transition surface; wherein the flared section has a lower end and an upper end.

[0008] The tooth height of the first helical tooth increases from bottom to top along the axial direction, from zero to H, and the tooth height of the second helical tooth is H.

[0009] Viewed from the longitudinal section of the drill body, the helical tooth has multiple tooth sections, which are arranged in a spaced-out manner along the vertical direction; each tooth section includes an upper tooth surface, a tooth tip, and a lower tooth surface, the tooth tip is arc-shaped, and both the lower tooth surface and the upper tooth surface are tangent to the tooth tip; the drill body axis forms a set angle with the upper tooth surface of the tooth section.

[0010] The relevant content in the above plan is explained as follows:

[0011] In the above scheme, the tooth height of the first helical tooth increases from zero to H from bottom to top. That is, from bottom to top, the initial tooth height of the first helical tooth is zero, and the tooth height at the end of the first helical tooth is H. The distance from the tooth tip of the first helical tooth to the drill shaft axis is called the initial helical radius of the first helical tooth, which is assumed to be equal to Rx. Therefore, the distance from the tooth tip of the first helical tooth to the drill shaft axis, that is, the helical radius at the end of the first helical tooth, is Rx+H. The tooth height of the second helical tooth is H. The distance from the tooth tip of the second helical tooth to the drill shaft axis is called the tooth tip helical radius of the second helical tooth, which is assumed to be equal to Rd. Therefore, Rd=Rx+H.

[0012] In the above scheme, the preferred angle α is 30° to 60°. At this angle, a more efficient vertical component can be obtained in the upward force applied to the upper tooth surface, making it easier to lift the flange.

[0013] The head of the drawing drill can be a dovetail slotted cutting tool, a milling cutter, or a twist drill head. A drill shank is located at the upper end of the drawing drill, coinciding with the axis of the drill head and the drill body. The drill shank can have a prismatic structure to facilitate heat dissipation, and it can be mounted on a machine tool. While the machine tool rotates the drawing drill, it also provides axial feed.

[0014] In the above solution, the helical teeth can apply an upward force to the edge of the hole, scraping the edge of the hole toward the outside of the pipe, thereby preventing the edge from turning over and entering the inside of the pipe; at the same time, since the drilling force and the turning force applied to the pipe are both achieved by the pull hole drill outside the pipe, compared with the turning force applied from inside the pipe to outside, the requirements for the pipe clamping mechanism in this utility model are lower, and the pipe will not easily shake.

[0015] In some specific embodiments, the bottom end of the lower tooth surface and the bottom end of the upper tooth surface are both located on the circumference of the drill body to form the tooth bottom; the tooth top is a circular arc, an elliptical arc, or a parabola.

[0016] The tooth tip is a circular arc, elliptical arc, or parabola. This reduces friction when the tooth contacts the inner wall of the flange, making it less likely to damage the inner wall of the flange and easier to embed into the flange.

[0017] In some specific embodiments, the number of the first helical teeth and the second helical teeth is equal, which is one. The first helical teeth and the second helical teeth are connected as one unit, and the end point of the first helical teeth is the start point of the second helical teeth.

[0018] In a further technical solution, the number of the first helical racks is less than the number of the second helical racks; each first helical tooth and a corresponding second helical tooth are smoothly connected along the drill body axis through a transition surface, and the curvature of the surface at the connection is continuous to avoid geometric protrusions.

[0019] When the arc distance between adjacent helical teeth is large, once the flange cools and shrinks, deformation occurs at the gap. The design of multiple second helical teeth can provide support at the gap, further supporting the flange to ensure that the flange has a cylindrical structure.

[0020] Setting multiple first helical teeth can improve the flanging efficiency.

[0021] The helical teeth are preferably right-hand threads. This is because most machine tool heads are currently designed clockwise, allowing the drilling drill to be mounted on existing machine tools to complete the drilling process.

[0022] The tooth height of the first helical tooth gradually increases from zero to H, which allows for a slow flanging operation and prevents the hole from breaking during the flanging process.

[0023] In a further technical solution, the lower end of the first helical tooth is the initial helical end, and the upper end is the terminating helical end. The tooth height of the initial helical end is zero, and the tooth height of the terminating helical end is H.

[0024] With the above design, the first helical tooth can be inserted into the hole through the initial helical end, which makes it easier to lift the flange.

[0025] In a further technical solution, the tooth tips of the first helical teeth are distributed on the side of a frustum; the frustum is a truncated cone, an ellipsoidal frustum, or a parabolic frustum.

[0026] This design allows the first helical tooth to achieve the purpose of flaring, because the diameter of a frustum, ellipsoid, or paraboloid increases from the end to the bottom, making flaring easy.

[0027] A further technical solution is that the diameter of the end head is equal to the diameter of the drilling head; the diameter of the end base is equal to the diameter of the hole diameter determination section. With the above design, the initial helical end of the first helical tooth can normally enter the hole, and the terminating helical end can sufficiently enlarge the flange.

[0028] It should be noted that there are one or more second helical teeth forming the aperture-determining segment.

[0029] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0030] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0031] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0032] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the case.

[0033] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0034] The working principle and advantages of this utility model are as follows:

[0035] This invention uses a drilling head to drill a hole in the pipe wall. The radius of the hole corresponds to the initial helical radius Rx of the first helical tooth (which can be equal to Rx). The initial helical end of the first helical tooth enters the hole, and the edge of the hole is turned outward to form an initial notch. From this point onward, the subsequent segments of the first helical tooth sequentially and continuously enter the hole downward. The helical radius of the tip of the subsequent segment of the first helical tooth is always greater than the helical radius of the tip of the previous segment. Therefore, the first helical tooth always contacts the subsequent edge of the hole at some point and applies an upward and outward force to the subsequent edge of the hole, causing the subsequent edge of the hole to bend upward and outward continuously until the end of the first helical tooth enters the hole and causes the edge of the hole to bend upward and outward, thus forming a cylindrical structure. Then, the second helical tooth enters the hole and expands the diameter of the cylindrical structure to complete the drilling.

[0036] This invention uses helical teeth to apply an upward force to the edge of the hole, scraping the flange towards the outside of the pipe, thus preventing the flange from entering the inside of the pipe. At the same time, since the drilling force and flange force applied to the pipe are both achieved through a pull-out drill outside the pipe, compared to applying force from inside the pipe to the outside for flange application, this invention has lower requirements for the pipe clamping mechanism and will not easily cause pipe shaking.

[0037] In summary, compared with the prior art, this utility model applies force to the edge of the hole from the outside by means of spiral teeth, which is set outward and upward. This avoids the phenomenon that it is impossible to construct the curved pipe when the force is applied from the inside of the hole outward for hole pulling. At the same time, the first spiral teeth will directly lift and turn the edge of the hole, without softening or melting the pipe metal. It is less difficult to process and there will be no softened metal material distributed inside the pipe. Attached Figure Description

[0038] Appendix Figure 1 This is a schematic diagram of the overall structure of the hole-pulling drill in an embodiment of this utility model;

[0039] Appendix Figure 2 for Figure 1 Enlarged view of part Q in the image;

[0040] Appendix Figure 3 This is a schematic diagram of the upper tooth surface structure of the helical teeth in an embodiment of the present utility model;

[0041] Appendix Figure 4 This is a schematic diagram of the drill body structure in an embodiment of the present utility model;

[0042] Appendix Figure 5 This is a schematic diagram showing the simplified spiral teeth as a spiral line in the embodiments of this utility model.

[0043] Appendix Figure 6This is a schematic diagram showing the corresponding connection of the first and second spiral teeth in an embodiment of the present invention when both the first and second spiral teeth are multiple and equal (both the first and second spiral teeth are two in number and simplified as spiral lines).

[0044] Appendix Figure 7 This is a schematic diagram of the connection when the number of first spiral teeth is less than the number of second spiral teeth in an embodiment of this utility model (the first spiral tooth is one line, and the second spiral tooth is two lines, both of which are simplified to spirals).

[0045] Appendix Figure 8 This is a schematic diagram of the principle of the hole-pulling drill in this embodiment of the present invention when it is about to pull a hole in the pipe (the helical teeth are simplified to a helical line).

[0046] Appendix Figure 9 This is a schematic diagram of the drilling drill contacting the pipe in an embodiment of the present invention (the spiral teeth are simplified to a spiral line).

[0047] Appendix Figure 10 This is a schematic diagram of the drilling head of the present utility model when drilling into the pipe (the spiral teeth are simplified to a spiral line).

[0048] Appendix Figure 11 This is a schematic diagram of the first spiral tooth drilling into the pipe in an embodiment of the present invention (the spiral tooth is simplified to a spiral line).

[0049] Appendix Figure 12 This is a schematic diagram of the borehole diameter determination section when the pipe has just been drilled through in an embodiment of this utility model (the spiral teeth are simplified to a spiral line).

[0050] Appendix Figure 13 This is a schematic diagram of the hole diameter determination section in this utility model embodiment when the hole has just penetrated the pipe and there is a certain distance between the hole-pulling drill head and the bottom of the pipe (the helical teeth are simplified to a helical line).

[0051] Appendix Figure 14 This is a schematic diagram of the orifice-determining section fully entering the pipe in an embodiment of the present invention (the spiral teeth are simplified to a spiral line).

[0052] Appendix Figure 15 This is a schematic diagram illustrating the force exerted by the spiral teeth on the edge of the hole in an embodiment of the present invention (the spiral teeth are simplified to a spiral line).

[0053] Appendix Figure 16 This is a schematic diagram of the longitudinal section structure of the hole-pulling drill in the embodiment of this utility model;

[0054] Appendix Figure 17 This is a schematic diagram of the gradual change in the helical radius of the first helical tooth in an embodiment of this utility model (view from below).

[0055] Appendix Figure 18This is a schematic diagram of the initial notch structure in an embodiment of the present utility model (top view).

[0056] Appendix Figure 19 This is a schematic diagram (top view) of a first spiral tooth enlarging half a turn in an embodiment of the present invention.

[0057] Appendix Figure 20 This is a schematic diagram (top view) of the embodiment of the present invention after setting two first spiral teeth to enlarge the hole by half a turn.

[0058] Appendix Figure 21 This is a schematic diagram of the cylindrical structure in an embodiment of the present utility model (top view).

[0059] Appendix Figure 22 Schematic diagrams of three implementation schemes of the frustum provided by this utility model.

[0060] In the above figures: 1. Drill head; 2. Drill body; 3. Drill shank; 4. Flaring section; 5. Hole diameter defining section; 6. Tooth; 7. Terminating helical end; 8. Helical tooth; 9. Upper tooth surface; 10. End; 11. End bottom; 12. Lower tooth surface; 13. Tooth tip; 14. Pipe; 15. Hole; 16. Initial notch; 17. Cylindrical structure; 18. Initial helical end; I. Frustum conicum; II. Parabolic truncated cone; III. Frustum ellipsoid;

[0061] 8a. First helical tooth; 8b. Second helical tooth;

[0062] L1, drill body axis; α, set angle;

[0063] A. Anterior teeth; B. Rear teeth; C. Upper teeth. Detailed Implementation

[0064] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0065] Example: The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the examples of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0066] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0067] See appendix Figures 1-22As shown, a drilling drill includes a drilling head 1 and a drill body 2 arranged sequentially from bottom to top along the drilling feed direction, with their axes coinciding. The drill body 2 is provided with helical teeth 8, which include a first helical tooth 8a and a second helical tooth 8b arranged sequentially from bottom to top along the circumference of the drill body 2. The first helical tooth 8a forms a flared section 4 on the drill body 2, and the second helical tooth 8b forms a hole diameter determining section 5 on the drill body 2. The first helical tooth 8a and the second helical tooth 8b are smoothly connected along the axial direction by a transition surface. The flared section 4 has a lower end head 10 and an upper end bottom 11.

[0068] The tooth height of the first helical tooth 8a increases from bottom to top along the axial direction, from zero to H. The tooth height of the second helical tooth 8b is H, as shown below. Figure 1 , Figure 4 , Figure 5 and Figure 16 As shown.

[0069] Viewed from the longitudinal section of the drill body 2, the helical tooth 8 has multiple tooth sections 6, which are arranged at intervals along the vertical direction. Each tooth section 6 includes an upper tooth surface 9, a tooth tip 13, and a lower tooth surface 12. The tooth tip 13 is arc-shaped, and both the lower tooth surface 12 and the upper tooth surface 9 are tangent to the tooth tip 13. The drill body axis L1 forms a set angle α with the upper tooth surface 9 of the tooth section 6. Figure 3 As shown.

[0070] In this embodiment, the tooth height of the first helical tooth 8a increases from zero to H from bottom to top. That is, the initial tooth height of the first helical tooth 8a is zero from bottom to top, and the tooth height at the end of the first helical tooth 8a is H. The distance from the tooth tip of the first helical tooth 8a at its initial position to the axis is called the initial helical radius of the first helical tooth 8a, which is assumed to be equal to Rx. Therefore, the distance from the tooth tip of the first helical tooth 8a at its end to the drill shaft axis L1, that is, the helical radius at the end of the first helical tooth 8a, is Rx+H. The tooth height of the second helical tooth 8b is H. The distance from the tooth tip of the second helical tooth 8b to the drill shaft axis L1 is called the helical radius of the tooth tip of the second helical tooth 8b, which is assumed to be equal to Rd. Therefore, Rd=Rx+H.

[0071] It should be noted that H, Rx, and Rd are all non-negative real numbers.

[0072] In this embodiment, the angle α is preferably set to 30° to 60°. At this angle, a more efficient vertical component force can be obtained in the upward force applied to the upper tooth surface 9, making it easier to lift the flange.

[0073] The head 1 of the drawing drill can be a dovetail slotted cutting head, a milling cutter head, or a twist drill head. A drill shank 3 is provided at the upper end of the drawing drill. The drill shank 3, the head 1, and the drill body 2 are aligned on the same axis. The drill shank 3 can have a prismatic structure to facilitate heat dissipation. The drill shank 3 can be mounted on a machine tool. While the machine tool rotates the drawing drill, the drawing drill also has axial feed.

[0074] In this embodiment, the edge of the hole 15 can be scraped towards the outside of the pipe 14 by applying an upward force to the edge of the hole 15 through the spiral teeth 8, thereby preventing the edge from turning over into the inside of the pipe 14; at the same time, since the drilling force and the turning force applied to the pipe 14 are both achieved by the pull hole drill outside the pipe, compared with the turning force applied from inside the pipe to outside, the clamping mechanism of the pipe 14 is less demanding in this utility model, and the pipe 14 will not easily shake.

[0075] Preferred, such as Figure 2 As shown, the tooth 6 includes a tooth tip 13, an upper tooth surface 9, and a lower tooth surface 12; the bottom end of the lower tooth surface 12 and the bottom end of the upper tooth surface 9 are both located on the circumference of the drill body 2 to form the tooth bottom; the lower tooth surface 12 and the upper tooth surface 9 are both tangent to the tooth tip 13.

[0076] The tooth tip 13 is a circular arc or an elliptical arc.

[0077] The tooth tip 13 is a circular arc, elliptical arc or parabola, so that when the tooth 6 contacts the inner wall of the flange, the friction is low, it is not easy to damage the inner wall of the flange and it is easier to embed into the inside of the flange.

[0078] The first helical tooth 8a and the second helical tooth 8b can be configured in the following ways, as detailed below:

[0079] I. For example Figure 1 and Figure 5 As shown, the first helical tooth 8a and the second helical tooth 8b each have one tooth, and the first helical tooth 8a and the second helical tooth 8b are connected as one unit. The end point of the first helical tooth 8a is the start point of the second helical tooth 8b.

[0080] II. Figure 6 As shown, when the number of the first helical teeth 8a and the second helical teeth 8b is equal and there are multiple such teeth, the example of drilling a hole in pipe 14 is used for illustration:

[0081] Combination Figure 6 and Figure 20The hole-drilling drill head 1 drills a hole 15 in the pipe 14. When the first helical tooth 8a enters the hole 15, one of the first helical teeth 8a intersects the pipe 14 at every moment. If the hole-drilling drill has two first helical teeth 8a, then each of the first helical teeth 8a intersects the pipe 14 at every moment. Assume there are two first helical teeth 8a, right-handed. The position of the front tooth A is 90° ahead of the rear tooth B (not limited to 90 degrees, it can also be 30 degrees, 60 degrees, or 45 degrees, etc.). From a top-view angle, take the cross-section of the hole-drilling drill itself as an example. The front tooth A starts drilling at position A1, and the rear tooth B starts drilling at position B1. After the drilling drill rotates 90° and feeds axially, the front tooth A flares out to position A2, and the rear tooth B flares out to position B2. Then the drilling drill continues to rotate and feed axially, and 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 flaring of the front tooth A, that is, the flaring of the rear tooth at position B2 is based on the flaring at position A1.

[0082] Assuming four first helical teeth 8a are evenly arranged on the circumference, the resulting flared section 4 intersects the pipe 14 at four points at any given moment. The four first helical teeth 8a simultaneously begin drilling at their respective positions. When the drilling drill rotates 90° and feeds axially, the subsequent flaring action of each first helical tooth 8a is based on the flaring action of the preceding first helical tooth 8a. Similarly, when three first helical teeth 8a are set, the working principle is the same as that of the two first helical teeth 8a described above.

[0083] Obviously, the more first spiral teeth 8a that form the flared section 4, the less "amount" of pressure is applied to the edge of the hole 15 each time. Multiple progressive pressure flaring is beneficial to improving the quality of hole extraction.

[0084] Third, the number of first helical teeth 8a is less than the number of second helical teeth 8b; each second helical tooth 8b is smoothly connected to a unique first helical tooth 8a along the drill body axis L1 through a transition surface, and the curvature of the surface at the connection is continuous to avoid geometric protrusions.

[0085] When the arc distance between adjacent helical teeth 8 is large, once the flange cools and shrinks, deformation occurs at the interval. The above design can provide support at the interval to further support the flange and ensure that the flange has a cylindrical structure 17.

[0086] For reference Figure 7 The first helical tooth 8a has one tooth, namely the front tooth A, and the second helical tooth 8b has two teeth, one of which exists independently, namely the upper tooth C, and the other is connected to the first helical tooth 8a. At this time, the front tooth A serves the purpose of flanging and widening, while the two second helical teeth 8b can further support the cylindrical structure formed by the flanging.

[0087] It should be noted that the direction of rotation is used as the reference, and the following should be taken into account: Figure 7 In one or more spiral teeth, the second spiral tooth 8b connected to the first spiral tooth 8a is located in front, while the subsequent second spiral tooth 8b, such as the upper tooth C, is located behind the second spiral tooth 8b connected to the first spiral tooth 8a.

[0088] The spiral tooth 8 is preferably a right-hand thread. This is because most machine tool heads are currently designed clockwise, allowing the drilling drill to be mounted on existing machine tools to complete the drilling process.

[0089] Preferably, the lower end of the first helical tooth 8a is the initial helical end 18, and the upper end is the terminating helical end 7. The tooth height of the initial helical end 18 is zero, and the tooth height of the terminating helical end 7 is H.

[0090] The range from zero to H is gradually increased, which allows for a slow flanging operation and prevents the hole 15 from breaking during the flanging process.

[0091] With the above design, the first helical tooth 8a can be inserted into the hole 15 through the initial helical end 18, which makes it easier to lift the flange.

[0092] Preferred, such as Figure 21 The tooth tip 13 of the first helical tooth 8a is distributed on the side of a frustum, which is a frustum I, an ellipsoid III, or a parabolic frustum II.

[0093] Preferably, the diameter of the end 10 is equal to the diameter of the drilling head 1; the diameter of the end 11 is equal to the diameter of the hole diameter determining section 5. With the above design, the initial helical end 18 of the first helical tooth 8a can normally enter the hole 15, and the terminating helical end 7 can fully enlarge the flange.

[0094] It should be noted that there are one or more second helical teeth 8b forming the aperture-determining segment 5.

[0095] The gradient design of the first helical tooth 8a is to turn the edge of the hole 15 outward in a small number of times, so that the deformation of each turn is small and thus avoids breakage.

[0096] A schematic diagram of three ways in which the helical radius of the first helical tooth 8a gradually increases is shown in the appendix. Figure 22The tooth tip 13 of the first helical tooth 8a forming the flared section 4 is located on the side of the imaginary frustum, i.e., the side of the truncated cone. There are three frustum structures, all three having the same small end (i.e., end 10) radius equal to Rx and the same large end (i.e., end base 11) radius equal to Rd. The longitudinal sections of the three frustums are overlapped for comparison. In the schematic diagram of the longitudinal sections of the three frustums, the innermost is the truncated cone I, whose longitudinal section side is two oblique straight lines; the outermost is the ellipsoidal frustum III, whose longitudinal section side is a part of an ellipse, i.e. Figure 22 Midpoint line; the middle one is parabolic frustum II (i.e., a vertically placed frustum, the longitudinal section of which is part of a parabola). Figure 22 The middle dashed line.

[0097] The tooth portion 6 of the spiral tooth 8 is selected, and the tooth tip 13 of the spiral tooth 8 is a circular arc; the upper tooth surface 9 forms a 30° angle with the axis L1 of the drilling body and is tangent to the tooth tip 13; the lower tooth surface 12 forms a 30° angle with the axis L1 of the drilling body and is tangent to the tooth tip 13.

[0098] The helix angle of the first helical tooth 8a is the same as that of the second helical tooth 8b, which facilitates machining.

[0099] In the specific design, the drilling head 1 must drill through the pipe 14.

[0100] The main pipe is pipe 14 as described in this application. It should be noted that... Figure 15 In the diagram, F represents the upward force exerted by the helical tooth 8 on the edge of the hole 15; F1 represents the component of this upward force in the upward direction, which is parallel to the drill axis L1; and F2 represents the component of this upward force in the direction perpendicular to the drill axis L1.

[0101] The lower end of the first helical tooth 8a is the initial helical end 18, and the upper end is the terminating helical end 7. The machine tool drives the drilling drill to rotate and feed downwards, with the feed speed being less than the upward lifting speed of the first helical tooth 8a. For example, the first helical tooth 8a and the second helical tooth 8b each have one tooth, and the radius of the hole 15 drilled by the drill bit is equal to Rx.

[0102] The working process of the hole-pulling drill in this embodiment is described below:

[0103] Take the example of creating a hole in pipe 14.

[0104] First, the hole drill head 1 drills a hole 15 in the pipe 14, and the radius of the hole 15 is equal to Rx.

[0105] Secondly, the initial helical end 18 enters the hole 15 and applies an upward-sloping force to the edge of the contacting hole 15, as shown in the appendix. Figure 15Then, the initial small section of the first helical tooth 8a is successively inserted into the hole 15, forming an outwardly flared initial notch 16 at the edge of the hole 15, as shown in the appendix. Figure 18 .

[0106] The first helical tooth 8a always contacts a certain point on the edge of the hole 15. The helical radius of the tooth tip 13 of the first helical tooth 8a is always greater than the radius of the hole 15 at the contact point, thus always applying an upward force to the contact point.

[0107] Subsequently, the first helical tooth 8a continues to feed downwards, and the subsequent section of the first helical tooth 8a gradually enters the hole 15. Through the action of the first helical tooth 8a, the notch in the hole 15 gradually deepens and widens. Deepening—the radius of the initial notch 16 (the distance from the edge of the initial notch 16 to the center of the drill hole) gradually increases; widening—the arc angle of the initial notch 16 becomes larger and larger, but the entire hole 15 is not a complete circle, that is, there is a gap, and the edge of the hole 15 turns outwards and upwards; the first helical tooth 8a turns the edge of the hole 15. After rotating the pull drill 180°, the initial notch 16 of the hole 15 increases into an arc-shaped groove, as shown in the attached figure. Figure 19 The arc angle of the arc groove is 180°, and the arc angle between the deepest and shallowest points of the arc groove is also 180°. Until the termination point of the first helical tooth 8a, i.e., the termination helical end 7 (which is also the starting point of the second helical tooth 8b), contacts the edge of the hole 15 and causes the edge of the contact point to fold upwards and outwards, it immediately disengages from the edge of the hole 15. At this point, the shape of the entire hole 15 is not a complete circle; that is, the hole 15 has a connecting segment that requires further processing to transform the arc groove into a complete circle. The deepest point of this arc groove is where the termination point of the first helical tooth 8a disengages from the edge of the hole 15. The arc angle between the shallowest and deepest points of this arc groove is slightly less than 360°.

[0108] Then, the second helical tooth 8b is driven into the cylindrical structure 17. The helical radius of the tooth tip 13 at the starting point of the second helical tooth 8b is larger than the radius of the connecting section inside the hole 15 that needs further processing. Therefore, an upward force is applied to the edge of the hole 15, causing the connecting section that needs further processing to turn outward, so that the edge of the hole 15 turns outward into a cylindrical shape, as shown in the appendix. Figure 21 Then the drilling rig rotates 360° and feeds axially. After the connecting section is turned outward (at this time, the overall inner diameter of the cylindrical structure 17 is smaller than the helical diameter of the tooth tip 13 of the second helical tooth 8b), the second helical tooth 8b will expand while guiding the cylindrical structure 17 to turn outward further, until the inner diameter of the cylindrical structure 17 is equal to the helical diameter of the tooth tip 13 of the second helical tooth 8b.

[0109] Finally, the second helical tooth 8b is kept in contact with the cylindrical structure 17, and the drilling drill is kept rotating around its own axis to determine the diameter of the cylindrical structure 17, thus completing the drilling process.

[0110] Clearly, the lowermost part of the second helical tooth 8b, together with the first helical tooth 8a, completes the flaring. After the hole is drawn, there is another section of the second helical tooth 8b outside the flange of the hole, which further stabilizes the flange. In addition, the presence of another section of the second helical tooth 8b outside the flange of the hole facilitates heat dissipation for the second helical tooth 8b.

[0111] It should be noted that the helical radius of the tip 13 of the second helical tooth 8b cannot be greater than the radius of the pipe 14.

[0112] 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 the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A drilling drill, comprising a drilling head (1) and a drill body (2) arranged sequentially from bottom to top along the drilling feed direction, with their axes coinciding, characterized in that: The drill body (2) is provided with helical teeth (8), which include a first helical tooth (8a) and a second helical tooth (8b) arranged sequentially from bottom to top along the periphery of the drill body (2). The first helical tooth (8a) forms a flared section (4) on the drill body (2), and the second helical tooth (8b) forms a hole diameter determining section (5) on the drill body (2). The first helical tooth (8a) and the second helical tooth (8b) are smoothly connected along the axial direction by a transition surface. The tooth height of the first helical tooth (8a) increases from bottom to top along the axial direction, from zero to H, and the tooth height of the second helical tooth (8b) is H; Viewed from the longitudinal section of the drill body (2), the spiral tooth (8) has multiple teeth (6), and these teeth (6) are arranged in a spaced manner along the vertical direction; the tooth (6) includes an upper tooth surface (9), a tooth tip (13) and a lower tooth surface (12), the tooth tip (13) is arc-shaped, and the lower tooth surface (12) and the upper tooth surface (9) are both tangent to the tooth tip (13); the drill body axis (L1) is at a set angle (α) with the upper tooth surface (9) of the tooth (6).

2. The hole-drawing drill according to claim 1, characterized in that: The bottom end of the lower tooth surface (12) and the bottom end of the upper tooth surface (9) are both located on the circumferential surface of the drill body (2) to form the tooth bottom; The tooth tip (13) is a circular arc or an elliptical arc.

3. The hole-drawing drill according to claim 1, characterized in that: The number of the first helical teeth (8a) is equal to the number of the second helical teeth (8b).

4. The hole-drawing drill according to claim 1, characterized in that: The number of the first helical teeth (8a) is less than the number of the second helical teeth (8b); each of the first helical teeth (8a) and the corresponding second helical teeth (8b) are smoothly connected along the drill shaft axis (L1) through a transition surface, and the curvature of the surface at the connection is continuous to avoid geometric protrusions.

5. The drilling drill according to claim 3 or 4, characterized in that: The lower end of the first helical tooth (8a) is the initial helical end (18), and the upper end is the terminating helical end (7). The tooth height of the initial helical end (18) is zero, and the tooth height of the terminating helical end (7) is H.

6. The drilling drill according to claim 1, characterized in that: The tooth tip (13) of the first helical tooth (8a) is distributed on the side of a frustum; The frustum is a truncated cone (I), an ellipsoidal frustum (III), or a parabolic frustum (II).

7. The drilling drill according to claim 1, characterized in that: The flared section (4) has a lower end (10) and an upper end (11); the diameter of the end (10) is equal to the diameter of the hole-pulling drill head (1); the diameter of the end (11) is equal to the diameter of the hole-determining section (5).

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