Counterhook tool
By designing a reverse hook tool, the problem of exit burrs in hole machining was solved, achieving smooth diameter expansion of the hole wall and burr removal, simplifying the machining process and improving product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGDONG EVERWIN PRECISION TECH CO LTD
- Filing Date
- 2025-07-10
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies have the problem of not being able to effectively suppress exit burrs in hole processing, especially when using auxiliary pads, which increases the complexity of operation steps and equipment. Dry ice removal of burrs may cause plastic parts to become brittle, increasing the risk of brittle fracture.
The first through hole is machined from the exit side to the inlet side using a reverse hook tool. The reverse hook structure is formed by the inclined and curved cutting face and the cutting edge, which realizes the diameter expansion of the hole wall and removes burrs. The avoidance groove design facilitates the discharge of chips, and the back angle design prevents interference.
It effectively removes exit burrs in hole processing, simplifies operation steps, reduces equipment complexity and material embrittlement risk, and improves processing efficiency and product yield.
Smart Images
Figure CN224406501U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of product processing technology, and in particular to a reverse hook tool for hole machining. Background Technology
[0002] When machining through holes in the main body of a product, burrs often form at the hole exit end (i.e., the junction of the hole wall and the main body) when the drill bit penetrates the exit side of the main body. These burrs are mainly caused by plastic deformation and tearing of the material on the exit side due to insufficient rigid support when the drill bit is about to penetrate the workpiece.
[0003] To effectively suppress or reduce the formation of such exit burrs, a common process measure is to tightly support an auxiliary pad on the drill exit side. This auxiliary pad is typically made of a material harder or more wear-resistant than the workpiece material, and it must completely cover and extend beyond the drilling area. The core principle of this method is that the auxiliary pad increases the effective support thickness of the material on the exit side, enhancing the local rigidity support. When the drill bit penetrates, the auxiliary pad provides a strong reaction force, resisting the material deformation and tearing tendency caused by the drill bit's thrust, thereby reducing the height and number of burrs.
[0004] However, while adding auxiliary pads can suppress burrs at the through-hole exit, it also has some inherent drawbacks: (i) It adds extra operating steps, requiring positioning, placement, and securing of the auxiliary pad against the exit side for each hole machining operation. The auxiliary pad must be precisely aligned with the drilling position; otherwise, it cannot provide effective support or may interfere with machining, requiring additional positioning measures and increasing preparation time. The auxiliary pad needs to be tightly fitted against the exit side of the main body for support, which requires an additional pressure source (when the exit side is flat, the auxiliary pad needs to be pressed against the flat surface), increasing equipment complexity and cost. (ii) For main bodies with irregular shapes or protrusions or recesses on the exit side, it is difficult to find or manufacture pads that can fit perfectly and provide uniform support. For example, when the main body has a groove on the exit side, one of the groove walls is the exit side, requiring a specially made auxiliary pad adapted to the groove to be inserted into the groove to secure against the exit side. The shape and size of the auxiliary pad are difficult to control; when the auxiliary pad size is mismatched, it may damage the main body or fail to secure against the exit side.
[0005] When the outlet side of the main body is made of plastic, another process used is dry ice deburring. The main body is placed in a dry ice device, and ultra-low temperature freezing is used to make the plastic brittle. Then, the burrs are removed by the impact force of high-speed jets of dry ice particles and compressed air. The drawback of this process is that overall freezing can easily lead to excessive embrittlement of the plastic parts, significantly increasing the risk of brittle fracture or microcracks during subsequent processing or use. Utility Model Content
[0006] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is to provide a reverse hook tool.
[0007] To solve the above-mentioned technical problems, the present invention provides a reverse hook tool for machining a first through hole from the outlet side to the inlet side, so that the first through hole is machined to form a second through hole. The reverse hook tool includes a cutter shaft and a cutter body protruding from the outside of the cutter shaft. The protruding surface of the cutter body forms a first cutting surface. The cutter body also has a second cutting surface facing the inlet side. The second cutting surface is outward and inclined, bent, or curved towards the inlet side. The cutter body also has a first cutting edge formed at the intersection of the first cutting surface and the second cutting surface.
[0008] Furthermore, the vertical distance from the protruding surface of the blade to the rotation axis of the blade shaft is adapted to the radius of the second through hole; the distance between the protruding surface of the blade and the side of the blade shaft opposite to the protruding surface is less than the diameter of the first through hole.
[0009] Furthermore, the end of the cutter shaft away from the cutter body is configured as a fixed end; the second cutting face is distributed along the radial direction of the cutter shaft, and the inner end of the second cutting face is connected to the cutter shaft, while the outer end is bent, folded, or tilted outward and toward the fixed end before connecting to the second cutting face; the portion of the second cutting face radially close to the axis of the cutter shaft forms an avoidance groove; the width of the avoidance groove is configured to gradually increase from the front end to the rear end.
[0010] Furthermore, the blade also has a third blade adjacent to the first blade and facing a different direction, and a second blade is formed at a position between the third blade and the first blade, the length of the second blade being distributed along the axis of rotation.
[0011] Furthermore, the first cutting face has a first surface close to the second cutting edge and a second surface connected to the first surface away from the second cutting edge, a first clearance angle is formed between the first surface and the cutting plane of the second cutting edge, and a second clearance angle is formed between the second surface and the cutting plane of the second cutting edge.
[0012] Furthermore, the angle of the second rear angle is greater than the angle of the first rear angle.
[0013] Furthermore, one end of the cutter shaft near the cutter body is thinned to form a thinned portion, and the cutter body is formed at the end of the thinned portion.
[0014] Furthermore, the end of the cutter shaft away from the cutter body is configured as a fixed end; a notch is provided at the end of the cutter shaft near the cutter body, the notch extending radially outward through the cutter shaft and also extending axially away from the fixed end; the notch makes the thickness of the corresponding portion of the cutter shaft smaller than the diameter of the portion without the notch, so that the portion is thinned to form the thinned portion.
[0015] Furthermore, the cutter shaft is provided with a leveling position, which is a plane formed by cutting a portion of the outer surface of the cutter shaft; the orientation of the leveling position is consistent with the outward convex direction of the cutter body.
[0016] Furthermore, the cutter shaft has a first column, a cone formed at one end of the first column, and a second column formed at the end of the cone away from the first column; the large end of the cone is connected to the first column and is adapted to the diameter of the first column, and the small end is connected to the second column and is adapted to the diameter of the second column.
[0017] In summary, the reverse hook tool of this utility model has at least the following beneficial effects: During hole machining, the reverse hook tool processes the first through hole from the exit side to the inlet side, thereby enlarging the diameter of the first through hole to form the second through hole, which solves the problem of burrs at the exit end; the reverse hook tool, through the first cutting edge formed by the first cutting face and the second cutting face that are inclined, bent, or bent towards the inlet side, can effectively cut the hole wall from the exit side in the opposite direction, realizing the enlargement and finishing of the first through hole. The vertical distance from the first cutting face of the reverse hook tool to the axis of rotation is adapted to the radius of the second through hole, and the sum of the diameters of the first cutting face and the cutting shaft is less than the diameter of the first through hole, which can ensure that the tool body can smoothly enter and exit the first through hole, and also ensure that the reverse hook tool can process the second through hole with a larger diameter. The width of the clearance groove gradually increases from the front end to the rear end, which can avoid and guide the generated chips or burrs, facilitating the discharge of chips and / or burrs. The second cutting edge allows the first cutting edge to scrape away chips and / or burrs from the hole wall during the cutting process, further cleaning the chip and / or burrs inside the hole and increasing the smoothness of the hole wall. The first and second clearance angles not only prevent interference between the first cutting edge and the hole wall, but the larger angle of the second clearance angle also helps to avoid and guide the chips and / or burrs scraped by the second cutting edge, further facilitating their removal. The thinned portion both avoids interference with the hole wall and facilitates the design of the cutting tool body. Attached Figure Description
[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0019] Figure 1 This is a process flow diagram of one embodiment of the hole processing technology of this utility model.
[0020] Figure 2 This is a schematic cross-sectional view of the structure obtained in the first through-hole machining stage in one embodiment of the hole machining process of this utility model.
[0021] Figure 3 This is a schematic cross-sectional view of the structure obtained in the third through-hole machining stage in one embodiment of the hole machining process of this utility model.
[0022] Figure 4 This is a schematic cross-sectional view of the structure obtained in the first through-hole machining stage of a stepped structure in one embodiment of the hole machining process of this utility model.
[0023] Figure 5 This is a schematic cross-sectional view of the structure obtained in the first through-hole machining stage of a stepped structure in one embodiment of the hole machining process of this utility model.
[0024] Figure 6 This is a schematic cross-sectional view of the structure obtained in the finishing stage of a hole processing method according to an embodiment of the present invention.
[0025] Figure 7 This is a schematic diagram of the reverse hook tool used in one embodiment of the hole machining process of this utility model.
[0026] Figure 8 yes Figure 7 A magnified schematic diagram of part A in the middle.
[0027] Figure 9 This is a side view of the reverse hook tool used in one embodiment of the hole machining process of this utility model.
[0028] Figure 10 yes Figure 9 A magnified schematic diagram of part B in the middle.
[0029] Figure 11 This is a schematic diagram of the angles of the first and second rear angles.
[0030] Figure 12 This is a diagram showing the distribution of the reverse hook tool with the first through hole when the tool is in the initial / reset state.
[0031] Figure 13 This is a diagram showing the distribution of the offset between the rotation axis of the reverse hook tool and the axis of the first through hole.
[0032] Figure 14 It is a distribution diagram of the reverse hook tool located on the exit side and its rotation axis offset from the axis of the first through hole.
[0033] Figure 15It is a distribution diagram of the reverse hook tool located on the exit side with its rotation axis coinciding with the axis of the first through hole.
[0034] The diagrams in the instruction manual are labeled as follows:
[0035] Sidewall 100; Inlet side 100a; Outlet side 100b; Metal layer 101; Plastic layer 102; First through hole 10; Large diameter section 10a; Small diameter section 10b; Axis L2; Second through hole 20; Third through hole 30;
[0036] Reverse hook cutter 200; Rotation axis L1; Cutter shaft 210; Cutter body 220; Vertical distance D1; Distance D2; First cutting edge 22a; Second cutting edge 22b; First cutting face 221; First surface 221a; Second surface 221b; Cutting plane P; First clearance angle a; Second clearance angle b; Second cutting face 222; Avoidance groove 222a; Third cutting face 223; Leveling position 230; Detailed Implementation
[0037] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0038] The following disclosure provides various embodiments or examples of different features for implementing this utility model. Specific examples of components and arrangements will be described below to simplify the utility model. Of course, these are merely examples and are not intended to limit the utility model. For example, in the following description, forming a first component above or on a second component may include embodiments where the first and second components are in direct contact, or embodiments where other components may be formed between the first and second components such that the first and second components are not in direct contact. Additionally, reference numerals and / or characters may be repeated in various instances of the utility model. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations.
[0039] Furthermore, spatial relation terms such as "below," "under," "below," "above," and "above" may be used herein to readily describe the relationship between one element or component and another element (or component) or component (or component) as shown in the figure. In addition to the orientations shown in the figure, spatial relation terms will encompass various different orientations of the device in use or operation. The device may be positioned in other ways (rotated 90 degrees or in other orientations) and will be interpreted accordingly through the spatial relation descriptors used herein.
[0040] Furthermore, the technical parts described in this utility model and the appended claims are mainly the improved technical parts of this utility model, and do not limit the object protected by this utility model to only having these technical parts. Other known necessary components (structures and / or methods) and / or non-essential components of the protected object, other than the technical parts described in this utility model and the appended claims, are not included in this utility model and the appended claims because they do not involve the improvement scope of this utility model. However, this does not mean that the object protected by this utility model does not possess these known components.
[0041] Please see Figure 1 , Figure 1 This is a process flow diagram of one embodiment of the hole processing technology of this utility model. Figure 1 In the illustrated embodiment, the hole processing technology includes the following steps:
[0042] S100, Rough-machined hole: The first through hole 10 is rough-machined on the product.
[0043] Please see Figure 2 For example, taking one side wall 100 of the product as an example, a formed through hole with a diameter of 0.8 mm (hereinafter referred to as the second through hole 20, see...) is machined on the side wall 100. Figure 6 The second through hole 20 needs to penetrate the sidewall 100 along its thickness direction. During hole machining, machining proceeds from the outside (outer side of sidewall 100) to the inside (inner side of sidewall 100). Therefore, the outer side of sidewall 100 is called the inlet side 100a, and the inner side is called the outlet side 100b. The inlet side 100a refers to the side where the hole machining tool (or cutter) begins machining the hole, and the outlet side 100b refers to the side where the hole machining is completed. Alternatively, during hole machining, machining can proceed from the inside to the outside. Therefore, the inner side of sidewall 100 is called the inlet side 100a, and the outer side is called the outlet side 100b. Those skilled in the art will understand that the above description is merely illustrative and is not intended to limit the scope of the hole machining method of this utility model. The hole machining process of this utility model is applicable to any implementation scenario or embodiment of machining through holes on a product.
[0044] When machining the first through hole 10, a drill bit, milling cutter, or a known hole-making tool can be used to machine the first through hole 100 from the outside to the inside or from the inside to the outside. In this embodiment, a drill bit is used to machine the first through hole 10, which has a short machining time and high machining efficiency. The diameter of the first through hole 10 should be smaller than the diameter of the second through hole 20. For example, when the diameter of the second through hole 20 is configured to be 0.8 mm, the diameter of the first through hole 10 can be configured to be 0.7 mm. This makes the diameter of the first through hole 10 both smaller than and close to the diameter of the second through hole 20, which can reduce the machining amount in the subsequent finishing step and improve the machining efficiency of the subsequent finishing step.
[0045] Please see Figure 4 In the illustrated embodiment, to reduce the finishing area in subsequent steps and improve finishing efficiency, the first through hole 10 can be configured as a stepped hole, which is configured to have a small-diameter section 10b near the outlet side 100b and a large-diameter section 10a near the inlet side 100a and a larger-diameter section 10a. The diameter of the large-diameter section 10a is adapted to the diameter of the second through hole 20. Taking the second through hole 20 with a diameter of 0.8mm as an example, the diameter of the large-diameter section 10a is 0.8mm, and the diameter of the small-diameter section 10b is 0.7mm. The stepped first through hole 10 can be formed using the following processing technology:
[0046] S101. The third through hole 30 is machined using a hole machining tool whose diameter is compatible with the small hole diameter section 10b.
[0047] Please see Figure 3 The third through hole 30 is used to form the stepped first through hole 10. Taking the first through hole 10 with a large diameter section 10a of 0.8 mm and a small diameter section 10b of 0.7 mm as an example, the product is processed using a drill bit, milling cutter or known hole processing tool to process the third through hole 30 with a diameter of 0.7 mm that runs through the product wall thickness.
[0048] S102. Using a hole machining tool with a diameter adapted to the large diameter section 10a, the portion of the third through hole 30 corresponding to the large diameter section 10a is enlarged to form the first through hole 10.
[0049] Please see Figure 4 The diameter of a section of the third through hole 30 near the inlet side 100a (corresponding to the large diameter section) is enlarged using a drill bit, milling cutter, or a known hole-making tool to form the first through hole 10 with a large diameter at the inlet side 100a and a small diameter at the outlet side 100b.
[0050] As will be understood by those skilled in the art, the processing method for the stepped first through hole 10 is not limited to this, and it can be processed using any existing technical means capable of processing stepped holes. For example, the stepped first through hole 10 can also be directly rough-machined in one step using a stepped hole processing tool with a shape adapted to it. The stepped hole processing tool has a large outer diameter section adapted to the shape of the large diameter section 10a and a small outer diameter section adapted to the shape of the small diameter section 10b. For example, the diameter of the large outer diameter section of the stepped hole processing tool used is 0.8 mm, which is adapted to the large diameter section 10a, and the diameter of the small outer diameter section is 0.7 mm, which is adapted to the small diameter section 10b.
[0051] According to this embodiment, the first through hole 10 is machined into a stepped hole structure, with the larger diameter section 10a located near the inlet side 100a and the smaller diameter section 10b located near the outlet side 100b. Depending on the requirements of different embodiments, the axial dimension of the smaller diameter section 10b can be determined based on factors such as hole diameter, product wall thickness, and product material. Please refer to [link to relevant documentation]. Figure 5 For example, when the product is an injection-molded product with a metal structure and plastic injection molding, and the inlet side 100a is a metal structure and the outlet side 100b is a plastic structure, the small-diameter segment 10b can be located in the plastic structure, and the large-diameter segment 10a can be located in the metal structure. Taking the sidewall 100 as an example again, when the sidewall 100 is composed of a metal layer 101 located on the outer side and a plastic layer 102 located on the inner side, the large-diameter segment 10a is distributed in the metal layer 101 (penetrating the metal layer 101 along the wall thickness direction), and the small-diameter segment 10b is distributed in the plastic layer 102 (penetrating the plastic layer 102 along the wall thickness direction and coaxially connected to the large-diameter segment 10a).
[0052] The smaller the axial dimension of the small-diameter section 10b, the less time is required for subsequent finishing processes, thus improving finishing efficiency. However, the axial dimension of the small-diameter section 10b should not be reduced indefinitely, as this would be detrimental to subsequent finishing processes. For example, the axial dimension of the small-diameter section 10b should not be too thin, as this would be unfavorable for cutting with the reverse hook tool 200. In summary, the axial dimension of the small-diameter section 10b is determined based on factors such as the hole diameter, product wall thickness, and product material in different embodiments. This axial dimension can be determined through multiple experiments or through experience.
[0053] S200, Finished Hole: Please refer to Figure 6 A reverse hook tool 200 is used to pass through the first through hole 10 and enlarge the diameter of the first through hole 10 from the outlet side 100b to the inlet side 100a to form a finished second through hole 20. The reverse hook tool 200 can be any known reverse hook tool 200 used for hole machining.
[0054] Please see Figure 7 Based on the aforementioned structure of the first through hole 10, when the first through hole 10 is machined into a cylindrical through hole of equal diameter, the reverse hook tool 200 is used to enlarge the diameter of the first through hole 10 along the axis of the first through hole 10 from the outlet side 100b to the inlet side 100a, so that the enlarged diameter of the first through hole 10 forms the second through hole 20. In this embodiment, the reverse hook tool 200 is used to perform finishing on the first through hole 10 from the outlet side 100b to the inlet side 100a, which can remove burrs caused by insufficient rigid support at the outlet end of the first through hole 10 while enlarging the diameter. This solves the technical problems existing in the prior art, optimizes the hole processing technology, and improves the product yield. The term "outlet end" refers to the junction of the hole wall and the main body, such as the junction of the hole wall and the inner surface of the side wall 100.
[0055] Based on the above-described structure of the first through hole 10, when the first through hole 10 is machined into a stepped hole, the reverse hook tool 200 is used to enlarge the diameter of the small diameter section 10b along the axis of the first through hole 10 from the outlet side 100b to the inlet side 100a so that it can be adapted to the diameter of the large diameter section 10a, thereby forming the columnar second through hole 20 after the stepped first through hole 10 is machined.
[0056] Please see Figure 7 , Figure 7 The structure of a reverse hook tool 200 used in the hole machining process of this utility model is illustrated by way of example. The reverse hook tool 200 is fixed on the machining spindle and can rotate about the axis (rotation axis L1) under the rotational drive of the machining spindle, and can move along the axis under the linear drive of the machining spindle.
[0057] The reverse hook cutter 200 includes a cutter shaft 210 and a cutter body 220 protruding from the outside of the cutter shaft 210. The cutter body 220 is disposed at one end of the cutter shaft 210, and the end of the cutter shaft 210 away from the cutter body 220 is used to fix it to the machining spindle. A leveling position 230 may be provided on the cutter shaft 210. The leveling position 230 can be a plane formed by cutting a portion of the outer surface of the cutter shaft 210; that is, this plane is the leveling position 230, and it is concave within the outer surface of the cutter shaft 210. The orientation of the leveling position is consistent with the outward convex direction of the cutter body 220. The leveling position 230 helps to ensure that the rotation angle of the assembled cutter is consistent each time it is rotated and inserted into the tool holder, correcting the position and orientation of the cutter body 220, and fixing the orientation of the cutter body 220 of the reverse hook cutter 200 after each assembly.
[0058] During the process of forming the leveling position 230 by cutting the pin, a cut can be made radially towards the center along the cutter shaft 210, and then a cut can be made axially towards the end where the cutter body 220 is located. This ensures that the cutting position penetrates the cutter shaft 210 radially outward and also axially towards the cutter body 220. Specifically, the cutter shaft 210 has a first column 211, a cone 212 formed at one end of the first column 211 (the end away from the fixed end), and a second column 213 formed at the end of the cone 212 away from the first column 211. The large end of the cone 212 is connected to the first column 211 and is adapted to the diameter of the first column 211, and the small end is connected to the second column 213 and is adapted to the diameter of the second column 213. The plane of the leveling position 230 is disposed on the outer surface of the first column 211 and the large end of the cone 212. Those skilled in the art will understand that the structure of the cutter shaft 210 should not be limited to the above embodiments. For example, the cutter shaft 210 may also be a column of uniform diameter. As another example, the cutter shaft 210 may be a stepped column, i.e., the cutter shaft 210 has a first column 211 and a second column 213 formed at the end of the first column 211 away from the fixed end.
[0059] Please see Figure 9 and Figure 10 The blade 220 protrudes outward from the cutter shaft 210 in the radial direction. In an embodiment where the reverse hook cutter 200 is provided with a leveling position 230, the orientation of the blade 220 is consistent with the orientation of the leveling position 230. The vertical distance D1 from the protruding surface (i.e., the first cutting face) of the blade 220 to the rotation axis L1 of the cutter shaft 210 is adapted to the radius of the second through hole 20. For example, when the diameter of the second through hole 20 is 0.8 mm, the vertical distance D1 from the protruding surface of the blade 220 to the rotation axis L1 of the cutter shaft 210 is also 0.4 mm, so that a second through hole 20 with a diameter of 0.8 mm can be machined around the rotation axis L1. The distance D2 between the protruding surface of the blade 220 and the side of the blade shaft 210 opposite to the protruding surface is less than the diameter of the first through hole 10. That is, the sum of the diameter of the section of the blade 220 disposed on the blade shaft 210 or the section used to pass through the through hole (e.g., the second column 213 mentioned above) and the protruding dimension of the blade 220 is less than the diameter of the first through hole 10 (the minimum diameter, e.g., the diameter of the small diameter section 10b mentioned above), so that the blade 220 can smoothly pass through the first through hole 10. For example, when the diameter of the first through hole 10 is 0.7 mm, the sum of the diameter of the blade 220 and the protruding dimension of the blade 220 is 0.6 mm. In this embodiment, the protruding dimension of the blade 220 is approximately 0.1 mm, which matches the difference in diameter between the first through hole 10 and the second through hole 20.
[0060] Please see Figure 8 The blade 220 has a first cutting edge 22a that hooks back towards the inlet side 100a. A protruding surface of the blade 220 forms a first cutting face 221. The blade 220 also has a second cutting face 222 facing towards the inlet side 100a. The second cutting face 222 is inclined, bent, or curved outwards and towards the inlet side 100a. The junction between the first cutting face 221 and the second cutting face 222 is the first cutting edge 22a. Specifically, the first cutting face 221 is configured to be distributed along the axial direction of the blade shaft 210, and the second cutting face 222 is distributed along the radial direction of the blade shaft 210. The inner end (the end closer to the axis) of the second cutting face 222 is connected to the blade shaft 210, and the outer end is bent, folded, or inclined outwards and towards the fixed end before connecting to the end of the second cutting face 221 facing the fixed end to form the first cutting edge 22a. The second cutting face 221 forms a clearance groove 222a along its radial direction near the axis. This clearance groove 222a is used to avoid machining chips and prevent clogging. The width of the clearance groove 222a can be configured to gradually increase from the front end to the rear end, where the front end is the end facing the rotation direction and the rear end is the end facing away from the rotation direction. For example, when the cutter shaft 210 is configured to cut the hole wall based on clockwise rotation, the front end is the end facing the clockwise rotation direction, such as the left end shown in the figure, and the end facing away is correspondingly configured as the right end. As another example, when the cutter shaft 210 is configured to cut the hole wall based on counterclockwise rotation, the front end is the end facing the counterclockwise rotation direction, such as the right end shown in the figure, and the end facing away is correspondingly configured as the left end.
[0061] The cutting edge 220 also has a third cutting edge 223 adjacent to the first cutting edge 221 but facing a different direction. The third cutting edge 223 is formed on one side of the cutting edge 220 facing the rotation direction (e.g., the left side in the figure). The third cutting edge 223 and the first cutting edge 221 are located at the same horizontal position on the cutting axis 210. A second cutting edge 22b is formed at the position (intersection) between the third cutting edge 223 and the first cutting edge 221, and the length of the second cutting edge 22b is distributed along the rotation axis L1. The second cutting edge 22b is used to work in conjunction with the first cutting edge 22a in the finishing hole step. When the first cutting edge 22a cuts the hole wall, the second cutting edge 22b can scrape off burrs or chips from the inner wall of the hole.
[0062] Please see Figure 11The first cutting face 221 has a first surface 221a near the second cutting edge 22b and a second surface 221b connected to the first surface 221a away from the second cutting edge 22b. A first clearance angle α is formed between the first surface 221a and the cutting plane P of the second cutting edge 22b, and a second clearance angle b is formed between the second surface 221b and the cutting plane P of the second cutting edge 22b. The angle of the second clearance angle b is greater than the angle of the first clearance angle α. The setting of the first clearance angle α and the second clearance angle b can prevent the first cutting face 221 from interfering with the hole wall. Furthermore, based on the above-mentioned specific angle design, the chips can be guided and avoided through the space created by the first clearance angle α and the second clearance angle b, facilitating chip discharge.
[0063] In the illustrated embodiment, a notch is formed on a section of the cutter shaft 210 (second column 213) away from the fixed end. The notch extends radially outward through the cutter shaft 210 and also axially away from the fixed end. The notch causes the thickness of the corresponding portion of the cutter shaft 210 (first column 211) to be less than the diameter of the portion without the notch, thus thinning that portion to form a thinned portion. In other embodiments, the thinned portion can also be formed by thinning both opposite sides of the cutter shaft 210. The blade 220 is formed at the end of the thinned portion, i.e., the blade 220 protrudes outward from one lateral side of the thinned portion. The third cutting surface 223 of the blade 220 is on the same plane as the bottom surface of the notch. This design facilitates the placement of the blade 220 in the thinned portion and allows for chip clearance.
[0064] Based on the above-described reverse hook tool 200 structure, the finishing step includes the following sub-steps:
[0065] S201. Drive the reverse hook cutter 200 to move horizontally a predetermined distance away from the protruding surface, so that the rotation axis L1 is offset from the axis L2 of the first through hole 10, so that the reverse hook cutter 200 can pass smoothly through the first through hole 10.
[0066] Please see Figure 12 and Figure 13Based on the aforementioned reverse hook cutter 200 structure, the cutter body 220 protrudes from one side of the cutter shaft 210, and the distance from the protruding surface of the cutter body 220 to the rotation axis L1 is adapted to the radius of the second through hole 20. During the machining of the first through hole 10, it is necessary to ensure that the rotation axis L1 coincides with the axis L2 of the first through hole 10. Therefore, in the initial / reset state, the rotation axis L1 of the cutter shaft 210 is designed to coincide with the axis L2 of the first through hole 10. Since the radius of the first through hole 10 is smaller than the radius of the second through hole 20, the radius of the first through hole 10 is smaller than the distance from the protruding surface of the cutter body 220 to the rotation axis L1. In this state, the cutter body 220 is blocked by the inlet side 100a of the first through hole 10, preventing the cutter body 220 from entering the first through hole 10. In summary, before the blade 220 enters the first through hole 10, the reverse hook cutter 200 needs to be moved a certain distance away from the protruding surface. The moving distance must be such that the reverse hook cutter 200 is completely within the range of the first through hole 10 after being moved, so that the blade 220 and the section of the cutter shaft 210 (second column 213) are not blocked by the inlet side 100a, and the blade 220 can smoothly enter and exit the through hole.
[0067] S202, drive the reverse hook cutter 200 through the first through hole 10 and position it at the outlet side 100b of the first through hole 10.
[0068] Please see Figure 14 In this state, the blade 220 is misaligned with the first through hole 10 in the axial direction, so that the reverse hook tool 200 can be reset to the point where the rotation axis L1 coincides with the axis L2 of the first through hole 10.
[0069] S203. Drive the reverse hook cutter 200 to reset so that the rotation axis L1 of the cutter shaft 210 coincides with the axis L2 of the first through hole 10.
[0070] Please see Figure 15 When the reverse hook cutter 200 is reset, the second cutting surface 222 is located on the side of the outlet side 100b of the first through hole 10 (e.g., the inner side of the side wall 100), and the positions of the first cutting edge 22a and the second cutting edge 22b correspond to the positions of the hole wall of the second through hole 20.
[0071] S204. Drive the reverse hook cutter 200 to rotate around the rotation axis L1 and move towards the inlet side 100a to enlarge the diameter of the first through hole 10, thereby forming the second through hole 20.
[0072] In this step, the first cutting edge 22a cuts from the side of the outlet side 100b and gradually moves towards the inlet side 100a so that the first cutting edge 22a cuts the wall of the first through hole 10. At the same time, the second cutting edge 22b scrapes the wall of the hole after being cut by the first cutting edge 22a to remove residual burrs or debris, making the wall of the hole smoother. Thus, the first through hole 10 is enlarged to form the second through hole 20.
[0073] S300, Deburring inside the hole: Use a deburring tool to remove burrs inside the hole.
[0074] For the small amount of burrs or debris present in the hole, in some embodiments, a burr removal tool can be used to remove the small amount of burrs or debris remaining on the hole wall. For example, a drill bit adapted to the diameter of the second through hole 20 (by moving the drill bit in and out of the second through hole 20 once along the axial direction) or a milling cutter can be used to remove the burrs on the hole wall. Alternatively, a cylindrical roller or brush adapted to the second through hole 20 can be used to move the tool in and out of the second through hole 20 once along the axial direction, thereby removing the small amount of burrs or debris remaining in the hole wall. Another example is the use of existing gas or fluid methods to remove the small amount of burrs or debris in the hole wall. In other embodiments, for scenarios where the smoothness requirement of the hole is not high, step S300 can be omitted.
[0075] Based on the above embodiments, the hole processing technology has at least the following beneficial effects: Through a two-stage hole-opening process, a first through hole with a smaller diameter is first rough-machined, and then a reverse hook tool is used to cut the hole wall of the first through hole from the outlet side to the inlet side to form a second through hole with a larger diameter than the first through hole; this effectively avoids the problem of burrs forming on the outlet side due to insufficient support rigidity. The two-stage hole-opening process solves the problem of needing auxiliary pads and pressure sources to increase the rigidity of the outlet side in traditional technologies, saving manufacturing costs, optimizing the manufacturing process, and reducing equipment complexity. The two-stage process also solves the problem of product over-embrittlement caused by traditional dry ice deburring technology, improving product yield.
[0076] The above embodiments only illustrate preferred implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.
Claims
1. A counterhook tool for machining a first through hole in a direction from an exit side to an entrance side so that the first through hole is machined to form a second through hole, characterized by: It includes a cutting shaft and a blade protruding from the outside of the cutting shaft, the protruding surface of the blade forming a first cutting surface; the blade also has a second cutting surface facing the inlet side, the second cutting surface being outward and inclined, bent or curved towards the inlet side; the blade also has a first cutting edge formed at the intersection of the first cutting surface and the second cutting surface.
2. The counter-cutter according to claim 1, wherein: The vertical distance from the protruding surface of the blade to the rotation axis of the blade shaft is adapted to the radius of the second through hole; the distance between the protruding surface of the blade and the side of the blade shaft opposite to the protruding surface is less than the diameter of the first through hole.
3. The counterhook tool of claim 1, wherein: The end of the cutter shaft away from the cutter body is configured as a fixed end; the second cutting face is distributed along the radial direction of the cutter shaft, and the inner end of the second cutting face is connected to the cutter shaft, and the outer end is bent, folded or tilted outward and towards the fixed end before being connected to the second cutting face; the portion of the second cutting face radially close to the axis of the cutter shaft forms an avoidance groove; the width of the avoidance groove is configured to gradually increase from the front end to the rear end.
4. The counter-cutter of claim 1, wherein: The blade also has a third blade adjacent to the first blade and facing a different direction. A second cutting edge is formed at a position between the third blade and the first blade, and the length of the second cutting edge is distributed along the rotation axis of the blade shaft.
5. A counter-cutter according to claim 4, wherein: The first cutting face has a first surface close to the second cutting edge and a second surface connected to the first surface away from the second cutting edge. A first back angle is formed between the first surface and the cutting plane of the second cutting edge, and a second back angle is formed between the second surface and the cutting plane of the second cutting edge.
6. A counter-cutter according to claim 5, wherein: The angle of the second rear angle is greater than the angle of the first rear angle.
7. The counter-cutter of claim 1, wherein: The end of the cutter shaft near the cutter body is thinned to form a thinned portion, and the cutter body is formed at the end of the thinned portion.
8. A counter-cutter according to claim 7, wherein: The end of the cutter shaft away from the cutter body is configured as a fixed end; a notch is provided at the end of the cutter shaft near the cutter body, the notch extending radially outward through the cutter shaft and also extending axially away from the fixed end; the notch makes the thickness of the corresponding portion of the cutter shaft smaller than the diameter of the portion without the notch, so that the portion is thinned to form the thinned portion.
9. A counter-cutter according to any one of claims 1 to 8, wherein: The cutter shaft is provided with a leveling position, which is a plane formed by cutting a portion of the outer surface of the cutter shaft; the orientation of the leveling position is consistent with the outward convex direction of the cutter body.
10. A counter-cutter according to any one of claims 1 to 8, wherein: The cutter shaft has a first column, a cone formed at one end of the first column, and a second column formed at the end of the cone away from the first column; the large end of the cone is connected to the first column and is adapted to the diameter of the first column, and the small end is connected to the second column and is adapted to the diameter of the second column.