Positioning block for preventing rotation of drill bit and drill bit and machining method thereof

Abstract

The application relates to the technical field of machine tooling equipment, and discloses a positioning block for preventing rotation of a drill bit, the drill bit and a machining method. The positioning block comprises a head-changing drill bit module, and a boss structure is arranged at the top of the head-changing drill bit module; the boss structure is a hexahedral structure comprising a bottom surface, a top surface, two side surfaces and two end surfaces; the bottom surface of the boss structure is arranged at the top of the head-changing drill bit module; the top surface is a planar structure, the two side surfaces are first stress surfaces, and the two end surfaces are second stress surfaces; the first stress surfaces are a pair of planar surfaces which are centrosymmetric to each other, and the second stress surfaces are a pair of involute curved surfaces which are centrosymmetric to each other. The application effectively prevents relative rotation between a cutter body and the head-changing drill bit module during cutting, avoids causing blockage and affecting chip removal, and thus guarantees the stability of machining quality.

Description

Technical Field

[0001] This invention relates to the field of machining equipment technology, specifically to a positioning block for preventing drill bit rotation, the drill bit itself, and a machining method. Background Technology

[0002] In current drill bit grinding and cutting operations, replaceable drill bit modules are widely used to improve the applicability and ease of operation of drill bits. This design allows drill bit modules to be quickly changed according to different cutting requirements and material properties, thereby simplifying the drill bit changeover process and greatly improving work efficiency and flexibility.

[0003] However, despite the many advantages of replaceable drill modules, in practical applications, since the drill module and the cutter body are mainly fixed by installation connection, in a high-speed rotating environment, the connection between the drill module and the cutter body is not completely rigid. The small gaps and loose connections between the two can cause relative rotation under the action of centrifugal force and vibration, causing the drill's trajectory to deviate from the predetermined path during the cutting process, resulting in problems such as cutting deviation and increased roughness.

[0004] Furthermore, relative rotation can cause the cutting edge to rotate into the tool body, leading to the accumulation of drill chips in the gap between the drill module and the tool body, resulting in clogging. Drill chip clogging not only affects the drill's chip removal efficiency but can also cause overheating and accelerated wear, thus shortening the drill's lifespan. In addition, clogged drill chips can create additional resistance to the drilling process, further reducing drilling efficiency. Summary of the Invention

[0005] The present invention aims to provide a positioning block for preventing drill bit rotation, a drill bit thereof, and a processing method, in order to solve the problem that existing replaceable drill bit module structures are prone to relative rotation under high-speed rotation, which can easily cause blockage, thereby affecting the accuracy and quality of cutting and shortening the service life of the drill bit.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a positioning block for preventing drill bit rotation, comprising a drill bit changing module, wherein a boss structure is provided on the top of the drill bit changing module; the boss structure is a hexahedral structure, including a bottom surface, a top surface, two side surfaces, and two end surfaces; wherein the bottom surface of the boss structure is located on the top of the drill bit changing module; the top surface is a planar structure, the two side surfaces are first force-bearing surfaces, and the two end surfaces are second force-bearing surfaces; the first force-bearing surfaces are a pair of mutually centrally symmetrical planes, and the second force-bearing surfaces are a pair of mutually centrally symmetrical involute surfaces.

[0007] Furthermore, the height of the boss structure is 10% to 12.5% ​​of the drill bit diameter.

[0008] Furthermore, a positioning post is provided on the top surface of the boss structure.

[0009] Furthermore, the width of the first force-bearing surface is 25% to 30% of the drill bit diameter; the parametric equation of the second force-bearing surface is:

[0010]

[0011] Where r is the radius of the involute base circle; d is the drill bit diameter; a and b are constants used to adjust the roll angle of the involute curve to fit the drill bit space, where a[10,12], b[5,6]; t is the independent variable of the equation, t(0,1).

[0012] Because the boss structure is located in a confined internal cavity and the interacting contact surfaces are thin-walled, the geometry of the boss structure is constrained by the overall length of the second force-bearing surface to ensure that the first force-bearing surface can generate a thrust force to balance the cutting force during relative rotation, thereby reducing the relative rotation. This also ensures that the boss can be installed in the internal cavity and achieve a certain strength. For example, different base circle radii r and different parameters a and b will affect the length of the first force-bearing surface. Once the involute equation is determined, the width of the first force-bearing surface determines the overall "arc length" of the involute surface. The arc angle of the second force-bearing surface can be adjusted according to the parametric equation and design.

[0013] Meanwhile, this solution also provides a drill bit to prevent the drill bit from rotating, which is applied to the above-mentioned positioning block. It includes a cutter body, and a drill bit replacement module is provided at the bottom end of the cutter body; a positioning block is provided at the top of the drill bit replacement module; a limiting groove is provided at the bottom of the cutter body; and the positioning block is located in the limiting groove.

[0014] Furthermore, the limiting groove is a stepped groove, including a first stepped groove, a second stepped groove and a third stepped groove; the bottom surface of the first stepped groove is in contact with the top surface of the boss structure, the inner side of the second stepped groove is located on the outer side of the second force-bearing surface and the first force-bearing surface, and there is a certain gap; the third stepped groove is engaged with the middle of the head-changing drill bit module.

[0015] Furthermore, an inwardly recessed docking hole is provided in the middle of the first stepped groove, and the positioning post is disposed in the docking hole.

[0016] Furthermore, the height of the second step groove is consistent with the height of the boss structure; the inner side of the second step groove includes a first limiting surface corresponding to the first force-bearing surface and a second limiting surface corresponding to the second force-bearing surface.

[0017] In addition, this solution also provides a drill bit machining method to prevent drill bit rotation, applied to the aforementioned drill bit, including the following steps:

[0018] Step 1: Install the head-changing drill bit module in the limiting groove of the cutter body, so that the positioning pin is located in the docking hole and the positioning block corresponds to the first step groove and the second step groove;

[0019] Step 2: The workpiece is machined using a drill bit changing module. When the tool body rotates relative to the module, the first and second force-bearing surfaces come into contact with the tool body in sequence, generating relative forces to counteract the cutting rotation force.

[0020] Furthermore, when relative rotation occurs, the first force-bearing surface first contacts the first limiting surface and generates a relatively opposite thrust force to balance the current cutting force; when the cutting force is too large and the rotation reaches the critical point, the second force-bearing surface will contact the second limiting surface and generate friction force to balance the current cutting force.

[0021] The principle and advantages of this scheme are:

[0022] This solution, without altering the structure of the cutting tool and the head-changing drill module, cleverly incorporates a positioning block on the top of the drill module, allowing it to be directly installed within the tool's inner cavity. This enhances the limiting effect while effectively transmitting torque. Considering the thin-walled nature of the cutting tool, a dual-stage limiting structure is employed to effectively prevent relative rotation between the tool body and the head-changing drill module during cutting. This improves the overall structural torque strength and avoids blockages that could affect chip removal. Even in high-speed rotating environments, the tool remains resistant to drilling inefficiencies and precision losses caused by relative rotation, ensuring consistent product quality, significantly reducing rework, alleviating labor intensity, and effectively controlling production costs. Furthermore, this solution can be applied to the machining of various head-changing tool modules, enhancing its versatility. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the positioning block for preventing drill bit rotation according to the present invention.

[0024] Figure 2 This is a top view of the positioning block for preventing drill bit rotation according to the present invention.

[0025] Figure 3 This is a schematic diagram of the drill bit structure for preventing drill bit rotation according to the present invention.

[0026] Figure 4 This is a schematic diagram of the drill bit body structure for preventing drill bit rotation according to the present invention.

[0027] Figure 5 for Figure 4 A magnified schematic diagram of a portion of the structure in section A.

[0028] Figure 6This is a cross-sectional structural diagram of the drill bit body and the drill bit installation state of the present invention, which prevents the drill bit from rotating.

[0029] Figure 7 This is a schematic diagram of the force-bearing structure of the first limiting part of the drill bit processing method for preventing drill bit rotation according to the present invention.

[0030] Figure 8 This is a schematic diagram of the force-bearing structure of the second limiting part of the drill bit processing method for preventing drill bit rotation according to the present invention. Detailed Implementation

[0031] The following detailed description illustrates the specific implementation method:

[0032] The attached diagram is labeled as follows: cutter body 1, drill bit changing module 2, positioning block 3, protrusion structure 4, bottom surface 5, top surface 6, side surface 7, end face 8, positioning post 9, limiting groove 10, first step groove 11, second step groove 12, third step groove 13, docking hole 14, slot 15, first force-bearing surface b, second force-bearing surface a, first limiting surface b', second limiting surface a'.

[0033] In this embodiment, the positioning block 3, which prevents drill bit rotation, uses a protrusion structure 4 on the top of the drill bit module 2 and a double-segment limiting structure to gradually increase the overall structure's torsional resistance, thereby reducing the relative rotation between the drill bit module and the cutter body and ensuring the stability and accuracy of drilling operations. In this embodiment, as shown in the attached... Figure 1 As shown, the drill bit module 2 includes a spiral-shaped cutting head. A positioning block 3 is positioned above the cutting head. The positioning block 3 includes a protrusion structure 4 on the top of the drill bit module 2, used for limiting and transmitting torque. The protrusion structure 4 is a hexahedral structure, including a bottom surface 5, a top surface 6, two side surfaces 7, and two end surfaces 8. The bottom surface 5 of the protrusion structure 4 is directly formed on the top of the drill bit module, and its top surface is a planar structure. The overall height of the protrusion structure 4 is 10% to 12.5% ​​of the drill bit diameter. For example, if the drill bit diameter is 20mm, the corresponding height of the protrusion structure 4 is 2mm to 2.5mm. This ensures that the strength of the limiting protrusion increases proportionally with the increase of the cutting force as the drill bit diameter increases. In this embodiment, a positioning post 9 is also integrally formed on the top surface of the protrusion structure 4. The diameter of the positioning post 9 is set to 2-2.5mm, and the height is set to 2.5-3mm for stable installation.

[0034] In this embodiment, as shown in the appendix Figure 2 As shown, the two side surfaces 7 are the first force-bearing surfaces located on both sides of the protrusion structure 4, denoted as surface b. They are a pair of planar structures that are centrally symmetrical to each other. In this embodiment, the width of the pair of first force-bearing surfaces is 25% to 30% of the drill bit diameter. For example, if the drill bit diameter is 20mm, then the width of the corresponding first force-bearing surface is 5mm to 6mm.

[0035] The two end faces 8 are the second force-bearing surfaces located at both ends of the protrusion structure 4, denoted as surface a, and are a pair of involute surfaces with mutually centrally symmetrical cross-sections. That is, in this embodiment, the cross-sectional shape of the second force-bearing surface is two involutes with the same base circle radius but different roll angles, i.e., equidistant involutes. In this embodiment, the involute parametric equation of the second force-bearing surface cross-section is:

[0036]

[0037] Where r is the radius of the involute base circle, and in this embodiment, the value of r can be designed to be 7% to 7.5% of the drill bit diameter; d is the drill bit diameter; a and b are constants used to adjust the involute curve roll angle to adapt to the drill bit space, where a[10,12], b[5,6]; t is the independent variable of the equation, t(0,1).

[0038] The arc length of the involute curve is determined by the parametric equations of the second force-bearing surface and the width of the first force-bearing surface.

[0039] Because the boss structure 4 is set in a narrow inner cavity and the contact surfaces of the interaction are thin-walled, in order to ensure that the first force-bearing surface can generate a thrust force to balance the cutting force when relative rotation occurs, thereby reducing the relative rotation, and to ensure that it can be installed in the inner cavity and achieve a certain strength, the geometry of the boss structure 4 is constrained by the overall length of the second force-bearing surface. If the base circle radius r is different, the parameters a and b will be different, which will affect the length of the first force-bearing surface. Once the involute equation is determined, the width of the first force-bearing surface determines the overall "arc length" of the involute surface.

[0040] The second force-bearing surface in the tool body is also an involute. The cross-sectional shape of the drill bit's second force-bearing surface and the tool body's second force-bearing surface are two involutes with the same base circle radius but different roll angles, i.e., equidistant involutes. When one of the curves rotates around the center, there must be a certain rotation angle that makes the two curves coincide. Therefore, when the second force-bearing surface of the tool body and the second force-bearing surface of the drill bit come into contact and coincide, friction will be generated at the contact point. This friction will provide additional limiting force. Based on the characteristics of the involute, when the two curved surfaces completely coincide, theoretically every point on the curved surfaces will come into contact with each other and generate friction. To ensure the stable installation of the boss structure 4 and to achieve the effect of balancing the cutting force, effectively reducing relative rotation, the distance between the two involutes is 0.18mm to 0.22mm.

[0041] In addition, this embodiment also provides a drill bit to prevent drill bit rotation, applied to the aforementioned positioning block. (See attached image) Figure 3 As shown, the device includes a cutter body 1, with a drill bit changing module 2 mounted and connected to the bottom end of the cutter body 1. A positioning block 3, as described in this design, is provided on the top of the drill bit changing module 2.

[0042] As attached Figure 4 As shown, an inwardly recessed limiting groove 10 is provided at the bottom of the blade body 1. During connection, the positioning block 3 extends into the limiting groove 10 of the blade body 1 and is positioned and connected by the positioning pin 9.

[0043] As attached Figure 5 As shown, in this embodiment, the limiting groove 10 is a stepped groove, including a first stepped groove 11, a second stepped groove 12, and a third stepped groove 13. The first stepped groove 11 is located at the top of the limiting groove 10, and its shape corresponds to the shape of the boss structure 4. After connection, its bottom surface fits against the top surface of the boss structure 4. Furthermore, an inwardly recessed docking hole 14 is provided in the middle of the first stepped groove 11, allowing the positioning pin 9 to be placed within the docking hole 14 after connection, thereby achieving the positioning connection between the cutter body 1 and the head-changing drill bit module 2.

[0044] The second stepped groove 12 is located below the first stepped groove 11, and the height of the second stepped groove 12 is the same as the height of the boss structure 4. This ensures that after connection, the inner surface of the second stepped groove 12 is located outside the second and first force-bearing surfaces, with a certain gap between it and both surfaces, as shown in the attached diagram. Figure 6 As shown. In this embodiment, the inner surface of the second stepped groove 12 includes a first limiting surface, denoted as b', corresponding to the first force-b surface; and a second limiting surface, denoted as a', corresponding to the second force-bearing surface a. In this embodiment, the first limiting surface is a centrally symmetrical planar structure, and the second limiting surface is a centrally symmetrical involute curved surface.

[0045] As attached Figure 5 As shown, the third step groove 13 is located below the second step groove 12, and a slot 15 is provided between the third step groove 13 and the second step groove 12. The third step groove 13 and the slot 15 are used to engage with the middle part of the head-changing drill bit module 2, thereby installing the head-changing drill bit module 2 at the bottom end of the cutter body 1.

[0046] In addition, this embodiment also provides a drill bit machining method to prevent drill bit rotation. In this embodiment, the positioning block and drill bit can also be applied to other interchangeable modular cutting tool products. This embodiment uses its application in drill bit cutting tools as an example, including the following steps:

[0047] S1, as attached Figure 3 As shown, the drill bit changing module 2 is installed in the limiting groove 10 of the cutter body 1, so that the positioning pin 9 is located in the docking hole 14, and the positioning block 3 corresponds to the first step groove 11 and the second step groove 12. The first limiting surface b' of the second step groove 12 corresponds to the first force-b of the positioning block 3, and the second limiting surface a' corresponds to the second force-a.

[0048] In this embodiment, the positioning block 3 is set in the confined space inside the cutter body 1. The interacting contact surfaces are thin-walled, so two force-bearing surfaces are set to form a double-segment limit. The design of the relationship between the first and second limiting surfaces takes into account the principle and characteristics of the original structure's centering capability. The limiting surfaces are set as passive anti-torsion surfaces. That is, when the drill bit is pre-tightened and not subjected to cutting force, both the first and second limiting surfaces are in an "idle" state, that is, they do not contact any surface. In other words, there is a certain gap between them and both the first and second force-bearing surfaces, thereby ensuring the centering capability of the original structure of the drill bit interface.

[0049] S2 uses a drill bit changing module to process the workpiece; when the tool body rotates relative to the module, the first force-bearing surface and the second force-bearing surface come into contact with the tool body in sequence, and generate relative forces to counteract the cutting rotation force.

[0050] When the drill bit is rotating at high speed and subjected to cutting force, there is a tendency for relative motion between the head-changing drill bit module 2 and the cutter body 1. When the cutting force is greater than the static friction between the head-changing drill bit module 2 and the cutter body 1, a small relative rotation between the drill bit module and the cutter body 1 is allowed.

[0051] When the rotation reaches the initial point of the first limiting surface, the first stage of limiting occurs. At this time, the first force-bearing surface b first contacts the first limiting surface b'. Only the first force-bearing surface b and the first limiting surface b' are in contact, and the limiting effect is generated by the first limiting surface. The second limiting surface a' is empty, that is, there is no contact and no force is generated. The force situation of the positioning block 3 at this time is as shown in the attached figure. Figure 7 As shown, the first limiting surface will generate a relatively opposite thrust F. 止 Under the action of the thrust, the drill bit module is subjected to a pair of forces of the same magnitude but opposite direction to balance the current cutting force, thereby preventing the drill bit module from rotating relative to the cutter body 1.

[0052] When the cutting force of the drill bit continues to increase, exceeding the static friction of the system, the drill bit module 2 will continue to rotate relative to the drill body 1. When the rotation reaches a critical point, the first limiting surface b' will undergo elastic deformation, causing the first limiting segment to fail. That is, plastic deformation occurs, but the first force-bearing surface does not crack, so there is still a force, and the drill bit will continue to rotate relative to the drill. When the rotation angle is too large, the relative rotation reaches the starting point of the second limiting segment, causing the second limiting surface a' to come into contact with the second force-bearing surface a, generating friction and creating the second limiting segment. This friction increases the limiting force, achieving a double limiting effect based on the first limiting segment, thus increasing the overall structure's torsional resistance. In this embodiment, when the second limiting segment occurs, a frictional force dF will be generated. 摩Furthermore, based on the characteristics of the involute, namely that the normal to any point on the involute is tangent to the base circle, it is easy to deduce that the direction of the frictional force acting on any point on surface a is perpendicular to the normal at that point. The force state analysis is shown in the attached figure. Figure 8 As shown, then F 摩 =∫dF 摩 This allows the drill bit module to be held in place again to balance the current cutting force and prevent failure, thereby effectively ensuring the stability between the cutter body 1 and the head-changing drill bit module 2, reducing the risk of relative rotation, and improving the accuracy of the drill bit.

[0053] In this embodiment, a positioning block 3 structure is provided on the top of the head-changing drill module 2, and the positioning block 3 is placed in the inner cavity at the bottom of the cutter body. This increases the limiting and torque transmission without changing the external structure of the cutter, ensuring the original centering capability of the drill structure. Taking into account the thin-walled characteristics of the contact surface, a boss structure 4 is used to provide a double-stage limiting method. This double-stage limiting structure prevents relative rotation between the cutter body 1 and the head-changing drill module 2, increasing the overall structure's torsional resistance. This avoids relative rotation at high speeds that could cause the cutting edge to rotate into the cutter body, leading to chip blockage and affecting cutting efficiency and accuracy. This ensures product quality, reduces rework, effectively reduces labor intensity, and lowers production costs.

[0054] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A positioning block for preventing drill bit rotation, characterized in that: A dual-segment limiting structure is adopted to gradually increase the overall structure's torsional resistance and reduce the relative rotation between the drill bit module and the cutter body. It includes a head-changing drill bit module with a boss structure on its top. The boss structure is a hexahedron, including a bottom surface, a top surface, two side surfaces, and two end surfaces. The bottom surface of the boss structure is located on the top of the head-changing drill bit module. The top surface is a planar structure, the two side surfaces are first force-bearing surfaces, and the two end surfaces are second force-bearing surfaces. The first force-bearing surfaces are a pair of mutually centrally symmetrical planes, and the second force-bearing surfaces are a pair of mutually centrally symmetrical involute surfaces. The width of the first force-bearing surface is 25% to 30% of the drill bit diameter; the parametric equation of the second force-bearing surface is: ； ； Where r is the radius of the involute base circle; d is the drill bit diameter; a and b are constants used to adjust the involute curve roll angle, where a[10,12] and b[5,6]; t is the independent variable of the equation, t(0,1]. The positioning block is located in a limiting groove at the bottom of the cutter body. The limiting groove is a stepped groove, including a first stepped groove, a second stepped groove, and a third stepped groove. The inner side of the second stepped groove is located outside the second force-bearing surface and the first force-bearing surface, with a certain gap. The inner side of the second stepped groove includes a first limiting surface corresponding to the first force-bearing surface and a second limiting surface corresponding to the second force-bearing surface. When the rotation reaches the initial point of the first limiting surface, the first limiting occurs, and the first force-bearing surface contacts the first limiting surface first. When the rotation reaches the critical point, causing the first limiting to fail, the second limiting surface contacts the second force-bearing surface, generating friction and generating the second limiting.

2. The positioning block for preventing drill bit rotation according to claim 1, characterized in that: The height of the boss structure is 10% to 12.5% ​​of the drill bit diameter.

3. The positioning block for preventing drill bit rotation according to claim 1, characterized in that: A positioning post is provided on the top surface of the boss structure.

4. A drill bit that prevents the drill bit from rotating, characterized in that, The positioning block, applicable to any one of claims 1-3, includes a cutter body, a head-changing drill bit module at the bottom end of the cutter body, a positioning block at the top of the head-changing drill bit module, an inwardly recessed limiting groove at the bottom of the cutter body, and the positioning block disposed within the limiting groove.

5. The drill bit for preventing drill bit rotation according to claim 4, characterized in that: The bottom surface of the first step groove is in contact with the top surface of the boss structure, and the third step groove is engaged with the middle of the head-changing drill bit module.

6. The drill bit for preventing drill bit rotation according to claim 4, characterized in that: A recessed docking hole is provided in the middle of the first stepped groove, and the positioning post is located in the docking hole.

7. The drill bit for preventing drill bit rotation according to claim 5, characterized in that: The height of the second step groove is the same as the height of the boss structure.

8. The drill bit machining method for preventing drill bit rotation as described in any one of claims 4-7, characterized in that: Includes the following steps, Step 1: Install the head-changing drill bit module in the limiting groove of the cutter body, so that the positioning pin is located in the docking hole and the positioning block corresponds to the first step groove and the second step groove; Step 2: The workpiece is machined using a drill bit changing module. When the tool body rotates relative to the module, the first and second force-bearing surfaces come into contact with the tool body in sequence, generating relative forces to counteract the cutting rotation force.

9. The drill bit machining method for preventing drill bit rotation according to claim 8, characterized in that: When relative rotation occurs, the first force-bearing surface first contacts the first limiting surface and generates a relatively opposite thrust force to balance the current cutting force; when the cutting force is too large and the rotation reaches the critical point, the second force-bearing surface will contact the second limiting surface and generate friction force to balance the current cutting force.

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