Tapped repair tap, method for manufacturing the same, and tapped repair device

Abstract

The present application relates to the technical field of machining equipment, and provides an internal thread repair tap, a manufacturing method thereof and an internal thread repair device. The internal thread repair tap comprises a tool head, the tool head comprises a cutting part, the cutting part is provided with thread teeth and a guide cone surface, a guide cone tangent line of the guide cone surface is connected with N thread teeth, the thread angle of the thread teeth is gradually increased from the first thread tooth to the Nth thread tooth, the thread tooth is provided with a blade surface, the blade surface is provided with a relief angle, and the angle of the relief angle is negative. The internal thread repair tap provided in the embodiment of the present application optimizes the structure of the cutting part, makes the tap more easily introduced into the thread hole, improves the fitting degree with the internal thread tooth profile, and effectively repairs the internal thread.

Description

Technical Field

[0001] This invention relates to the field of machining equipment technology, and in particular to an internal thread repair tap, its manufacturing method, and internal thread repair equipment. Background Technology

[0002] Threaded connections are a common connection method in mechanical structures. During the assembly of mechanical components, there is a phenomenon of thread extrusion between the bolt and the internal thread. In addition, when mechanical components are subjected to strong impact forces, the bolt load will also impact the internal thread, causing the internal thread to deform and tilt.

[0003] When using existing spiral flute taps and straight flute taps for thread cutting and internal thread profile repair, it is impossible to guarantee that the tap can coincide with the original internal thread profile, and the original tap cannot be introduced, resulting in the inability to effectively repair the damage to the internal thread, and may even cause the threaded hole to be scrapped. Summary of the Invention

[0004] This invention provides an internal thread repair tap to solve the defects of existing repair taps, such as difficulty in introducing the tap into the threaded hole and mismatch with the original internal thread profile. It optimizes the structure of the cutting part, making it easier to introduce the tap into the threaded hole, improving the fit with the internal thread profile, and effectively repairing the internal thread.

[0005] The second aspect of this invention provides a method for manufacturing an internal thread repair tap.

[0006] A third aspect of the present invention provides an internal thread repair device.

[0007] A first aspect of the present invention provides an internal thread repair tap, comprising:

[0008] The cutting head includes a cutting part, on which threaded teeth and a guide cone surface are formed;

[0009] The tangent of the guide cone surface connects to N threaded teeth;

[0010] From the first thread tooth to the Nth thread tooth, the tooth profile angle of the thread tooth gradually increases;

[0011] The threaded teeth have a cutting edge, and a clearance angle is formed on the cutting edge, wherein the clearance angle is a negative value.

[0012] According to one embodiment of the present invention, N is 6, and the tooth profile angle of the first threaded tooth is 43°;

[0013] The rear angle is -13°.

[0014] According to one embodiment of the present invention, the internal thread repair tap is further provided with a chip removal groove, which extends along the axial direction of the tap, and two adjacent chip removal grooves are connected by the cutting edge.

[0015] According to one embodiment of the present invention, the chip removal groove includes a straight groove or a spiral groove.

[0016] According to one embodiment of the present invention, a rake angle is formed on the cutting edge, and the rake angle is located at the end of the cutting edge that contacts the cutting surface;

[0017] The angle range of the front angle is 8° to 10°.

[0018] According to one embodiment of the present invention, the cutting head further includes a calibration part, and the cutting part and the calibration part are arranged sequentially along the axial direction of the tap;

[0019] The calibration section has the threaded teeth formed thereon.

[0020] According to one embodiment of the present invention, the internal thread repair tap further includes a tool holder, and the cutting part, the calibration part, and the tool holder are connected in sequence along the axial direction of the tap;

[0021] An air inlet is formed inside the handle.

[0022] According to one embodiment of the present invention, the knife handle includes a shank portion and a square tail portion;

[0023] Along the axial direction of the tap, the cutting part, the calibration part, the shank part, and the square tail part are connected in sequence.

[0024] A second aspect of the present invention provides a method for manufacturing an internal thread repair tap based on any of the internal thread repair taps in the first aspect, comprising:

[0025] The cutting portion is ground along the tangent of the guide cone to form the guide cone surface, wherein the guide cone surface covers N-1 of the thread teeth;

[0026] Grind the 1st, 2nd, 3rd, ... Nth threaded teeth along the tooth profile outline of the tooth angle, wherein the tooth angle of the threaded teeth gradually increases from the first threaded tooth to the Nth threaded tooth;

[0027] The rear corner is ground along its outline so that the angle of the rear corner is negative.

[0028] A third aspect of the present invention provides a thread repair device, including an internal thread repair tap as described in any of the first aspects, or an internal thread repair tap manufactured based on the internal thread repair tap manufacturing method described in the second aspect.

[0029] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0030] According to the first aspect of the present invention, the internal thread repair tap has an optimized cutting section structure. Specifically, the internal thread repair tap includes a cutting head, which includes a cutting section. The cutting section has threaded teeth and a guide cone surface. The guide cone surface is a sloped surface. From the end of the cutting section to its tail, the diameter of the cutting section gradually increases. Furthermore, the guide cone tangent of the guide cone surface connects N threaded teeth, meaning the guiding distance of the guide cone surface is lengthened, making it easier for the lead portion of the internal thread repair tap to enter the threaded hole. From the first threaded tooth to the Nth threaded tooth, the threaded teeth... The tooth profile angle increases gradually, meaning the tooth profile angle of the first thread tooth is smaller than that of the second thread tooth, the second thread tooth is smaller than that of the third thread tooth, and so on. Based on this structure, the distance between the first and second thread teeth is greater than the distance between the second and third thread teeth, the distance between the second and third thread teeth is greater than the distance between the third and fourth thread teeth, and so on. A smaller tooth profile angle means thinner thread teeth, making it easier for the lead part of the internal thread repair tap to enter the threaded hole. Furthermore, the gradual transition of the thread profile angle from small to large to a standard angle improves the fit with the internal thread profile. The thread teeth covered by the guide cone are rectangular, and the lowered tooth crests prevent compression damage to the deformed internal thread crests. As the internal thread repair tap is screwed in, the rectangular thread teeth gradually compress the deformed internal thread, correcting it to a normal angle and restoring the pitch and tooth profile angle of the deformed internal thread. The cutting face on the threaded teeth is used for cutting the workpiece. A rake angle and a clearance angle are formed on the cutting face. The rake angle is located at the front end of the cutting face, and the clearance angle is located behind the rake angle. After grinding, the clearance angle is negative, which prevents shearing action on the deformed internal thread. It also allows the cutting part of the tap to change from a cutting state to a compressing state, pushing the deformed internal thread in the internal thread groove of the threaded hole, causing it to deform again and return to its normal state. In summary, the internal thread repair tap provided by this invention optimizes the structure of the cutting part, making the tap easier to introduce into the threaded hole, improving the fit with the internal thread profile, and effectively repairing the internal thread.

[0031] According to the method for manufacturing an internal thread repair tap provided in the second aspect of the present invention, the cutting part, the tooth profile angle of the thread teeth, and the clearance angle on the cutting surface of the internal thread repair tap are ground to lengthen the guiding distance of the guide cone surface, which makes it easier for the lead part of the internal thread repair tap to enter the threaded hole. After grinding, from the first thread tooth to the Nth thread tooth, the tooth profile angle of the thread teeth gradually increases, that is, the tooth profile angle of the first thread tooth is smaller than that of the second thread tooth, the tooth profile angle of the second thread tooth is smaller than that of the third thread tooth, and so on. Based on the above structure, the distance between the first thread tooth and the second thread tooth will be greater than the distance between the second thread tooth and the third thread tooth, the distance between the second thread tooth and the third thread tooth will be greater than the distance between the third thread tooth and the fourth thread tooth, and so on. The smaller the tooth profile angle of the thread teeth, the thinner the thread teeth, which makes it easier for the lead part of the internal thread repair tap to enter the threaded hole. Furthermore, the tooth profile angle of the thread teeth gradually transitions from small to large to a standard angle, which improves the fit with the internal thread profile. The thread teeth covered by the guide cone surface are rectangular, and the tooth crests are lowered, which avoids extrusion damage to the deformed internal thread crests. As the internal thread repair tap is screwed in, the rectangular thread teeth can gradually compress the deformed internal thread, gradually correcting it to a normal angle and restoring the pitch and tooth profile angle of the deformed internal thread. The back angle after grinding is negative, which will not have a shearing effect on the deformed internal thread. It can also change the cutting part of the tap from a cutting state to a compressing state, pushing the deformed internal thread in the internal thread groove of the threaded hole, causing it to deform again to restore it to a normal state. In summary, the internal thread repair tap made based on the internal thread repair tap manufacturing method provided in this embodiment of the invention can be more easily introduced into the threaded hole, improving the fit with the internal thread profile and effectively repairing the internal thread.

[0032] According to the third aspect of the present invention, the internal thread repair device uses an internal thread repair tap with an optimized cutting section structure. Specifically, the internal thread repair tap includes a cutting head, which includes a cutting section. The cutting section has threaded teeth and a guide cone surface. The guide cone surface is a sloped surface. From the end of the cutting section to its tail, the diameter of the cutting section gradually increases. Furthermore, the guide cone tangent of the guide cone surface connects N threaded teeth, meaning the guiding distance of the guide cone surface is lengthened, making it easier for the lead portion of the internal thread repair tap to enter the threaded hole. From the first threaded tooth to the Nth threaded tooth... The tooth profile angle of the threaded teeth gradually increases, that is, the tooth profile angle of the first threaded tooth is smaller than that of the second threaded tooth, the tooth profile angle of the second threaded tooth is smaller than that of the third threaded tooth, and so on. Based on the above structure, the distance between the first and second threaded teeth will be greater than the distance between the second and third threaded teeth, the distance between the second and third threaded teeth will be greater than the distance between the third and fourth threaded teeth, and so on. The smaller the tooth profile angle of the threaded teeth, the thinner the threaded teeth are, which makes it easier for the lead part of the internal thread repair tap to enter the threaded hole. Furthermore, the tooth profile angle of the thread teeth gradually transitions from small to large to a standard angle, which improves the fit with the internal thread profile. The thread teeth covered by the guide cone surface are rectangular, and the tooth crests are lowered to avoid extrusion damage to the deformed internal thread crests. As the internal thread repair tap is screwed in, the rectangular thread teeth can gradually compress the deformed internal thread, gradually correcting it to a normal angle and restoring the pitch and tooth profile angle of the deformed internal thread. The cutting surface on the thread teeth is the cutting surface used to cut the workpiece. A rake angle and a clearance angle are formed on the cutting surface. The rake angle is located at the front end of the cutting surface, and the clearance angle is located behind the rake angle. After grinding, the clearance angle is negative, so it will not shear the deformed internal thread. It can also change the cutting part of the tap from a cutting state to a compressing state, and push the deformed internal thread in the internal thread groove of the threaded hole, causing it to deform again to restore it to a normal state. In summary, the internal thread repair device provided by the embodiments of the present invention optimizes the structure of the cutting part, making it easier for the tap to be introduced into the threaded hole, improving the compatibility with the internal thread profile, and effectively repairing the internal thread. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a side view of the internal thread repair tap provided in an embodiment of the present invention;

[0035] Figure 2 This is a front view of the internal thread repair tap provided in an embodiment of the present invention;

[0036] Figure 3 This is a flowchart illustrating the method for manufacturing an internal thread repair tap according to an embodiment of the present invention.

[0037] Figure label:

[0038] 10. Tool tip; 12. Cutting section; 14. Threaded tooth; 15. Tooth profile; 16. Guide cone surface; 18. Guide cone tangent; 20. Cutting edge; 22. Clearance angle; 23. Clearance angle profile; 24. Chip groove; 26. Alignment section; 28. Tool holder; 30. Shank; 32. Square tail section;

[0039] 34. Standard guide cone tangent; 36. Standard tooth profile; 38. Standard back angle profile. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] like Figures 1 to 2 As shown, a first aspect embodiment of the present invention provides an internal thread repair tap, including a cutter head 10, the cutter head 10 including a cutting part 12, the cutting part 12 having threaded teeth 14 and a guide cone surface 16 formed thereon; the guide cone tangent 18 of the guide cone surface 16 connects N threaded teeth 14; from the first threaded tooth 14 to the Nth threaded tooth 14, the tooth profile angle of the threaded tooth 14 gradually increases; a cutting edge 20 is formed on the threaded tooth 14, and a clearance angle 22 is formed on the cutting edge 20, the clearance angle 22 being a negative value.

[0042] The cutting part 12 is located in the end region of the cutter head 10. The cutting part 12 is responsible for cutting. The guide cone surface 16 is actually a virtual surface composed of the top end faces of multiple thread teeth 14 located in this region. The guide cone tangent 18 of the guide cone surface 16 can be understood as the projection line of the guide cone surface 16 on the axial section of the internal thread repair tap. The guide cone tangent 18 is tangent to the top section of each thread tooth 14. Figure 1The difference between the guide cone tangent 18 and the standard guide cone tangent 34 in this embodiment of the invention is shown. The tooth profile angle of the thread tooth 14 refers to the included angle between the two side profile surfaces of the thread tooth 14. The tooth profile angles of the first N thread teeth 14 are all different, and from the first thread tooth 14 to the Nth thread tooth 14, the tooth profile angle of the thread tooth 14 gradually increases. The tooth profile angle of the (N+1)th thread tooth 14 is the standard tooth profile angle, which is usually 60°. The cutting surface 20 is located on a series of circular surfaces centered at points equidistant from the central axis of the internal thread repair tap and perpendicular to the central axis of the tap.

[0043] According to the first aspect of the present invention, the internal thread repair tap has an optimized structure for the cutting portion 12. Specifically, the internal thread repair tap includes a cutting head 10, which includes a cutting portion 12. The cutting portion 12 has threaded teeth 14 and a guide cone surface 16. The guide cone surface 16 is a sloped surface. From the end of the cutting portion 12 to its tail, the diameter of the cutting portion 12 gradually increases. Furthermore, the guide cone tangent 18 of the guide cone surface 16 connects N threaded teeth 14, meaning the guiding distance of the guide cone surface 16 is lengthened, making it easier for the lead portion of the internal thread repair tap to enter the threaded hole. From the first threaded tooth 14 to the Nth threaded tooth 14, the thread... The tooth profile angle of tooth 14 gradually increases, that is, the tooth profile angle of the first thread tooth 14 is smaller than that of the second thread tooth 14, the tooth profile angle of the second thread tooth 14 is smaller than that of the third thread tooth 14, and so on. Based on the above structure, the distance between the first thread tooth 14 and the second thread tooth 14 will be greater than the distance between the second thread tooth 14 and the third thread tooth 14, the distance between the second thread tooth 14 and the third thread tooth 14 will be greater than the distance between the third thread tooth 14 and the fourth thread tooth 14, and so on. The smaller the tooth profile angle of thread tooth 14, the thinner the teeth of thread tooth 14, which makes it easier for the lead part of the internal thread repair tap to enter the threaded hole. Furthermore, the tooth profile angle of the thread tooth 14 gradually transitions from small to large to a standard angle, which can improve the fit with the internal thread profile. The thread tooth 14 covered by the guide cone surface 16 is a rectangular thread tooth. The tooth tip of the thread tooth 14 is lowered, which can avoid extrusion damage to the deformed internal thread tip. As the internal thread repair tap is screwed in, the rectangular thread tooth can gradually extrude the deformed internal thread, gradually correcting the deformed internal thread to the normal angle and restoring the pitch and tooth profile angle of the deformed internal thread. The cutting surface 20 on the thread tooth 14 is a cutting surface used for cutting the workpiece. The cutting surface 20 has a rake angle and a clearance angle 22. The rake angle is located at the front end of the cutting surface 20, and the clearance angle 22 is located behind the rake angle. After grinding, the clearance angle 22 is negative, so it will not shear the deformed internal thread. It also allows the cutting part 12 of the tap to change from a cutting state to a pressing state, pushing the deformed internal thread in the internal thread groove of the threaded hole, causing it to deform again and return to its normal state. In summary, the internal thread repair tap provided by this embodiment of the invention optimizes the structure of the cutting part 12, making the tap easier to introduce into the threaded hole, improving the fit with the internal thread profile, and effectively repairing the internal thread.

[0044] In an embodiment of the present invention, N is 6, the tooth profile angle of the first threaded tooth 14 is 43°, and the angle of the back angle 22 is -13°. That is, the guide cone tangent 18 of the guide cone surface 16 connects 6 threaded teeth 14; from the first threaded tooth 14 to the sixth threaded tooth 14, the tooth profile angle of the threaded tooth 14 gradually increases from 43°. Specifically, the tooth profile angle of the first threaded tooth 14 is 43°, the tooth profile angle of the second threaded tooth 14 is 46°, the tooth profile angle of the third threaded tooth 14 is 48°, the tooth profile angle of the fourth threaded tooth 14 is 51°, the tooth profile angle of the fifth threaded tooth 14 is 53°, and the tooth profile angle of the sixth threaded tooth 14 is 57°. Further, starting from the seventh threaded tooth 14, the tooth profile angle is the standard tooth profile angle of 60°.

[0045] like Figure 1 As shown, in an embodiment of the present invention, a chip removal groove 24 is also formed on the internal thread repair tap. The chip removal groove 24 extends along the axial direction of the tap, and two adjacent chip removal grooves 24 are connected by a cutting edge 20. During the cutting process of the internal thread repair tap, chips are generated, which accumulate in the chip removal groove 24 and are eventually discharged from the chip removal groove 24.

[0046] In embodiments of the present invention, the chip removal groove 24 includes a straight groove or a spiral groove. If the chip removal groove 24 is a straight groove, the internal thread repair tap is suitable for machining blind holes and materials with powdery or strip-shaped chips, such as cast iron, cast steel, stainless steel, etc.; if the chip removal groove 24 is a spiral groove, the internal thread repair tap is suitable for machining blind holes and materials with continuous chips, such as aluminum, copper, zinc, stainless steel, etc.

[0047] The types of chip removal grooves 24 of the internal thread repair taps provided in this embodiment of the invention are not limited to the two examples mentioned above, and the structure can be designed according to actual processing requirements.

[0048] like Figure 2 As shown in the embodiment of the present invention, a rake angle is formed on the cutting surface 20, and the rake angle is located at the end of the cutting surface 20 that contacts the cutting surface; the angle range of the rake angle is 8° to 10°. The structural parameters of the rake angle have an important influence on the machining effect and service life of the internal thread repair tap. The rake angle refers to the angle at which the cutting part of the cutting surface 20 contacts the workpiece surface, and its size directly affects the cutting force, cutting temperature, and cutting quality. The angle range of the rake angle is 8° to 10° to balance cutting force, cutting quality, and service life.

[0049] like Figure 1As shown, in an embodiment of the present invention, the cutter head 10 further includes a calibration section 26. Along the axial direction of the tap, the cutting section 12 and the calibration section 26 are sequentially arranged; threaded teeth 14 are formed on the calibration section 26. The threaded teeth 14 on the calibration section 26 have a complete tooth profile and are mainly used to calibrate the size and shape of the thread, and also serve a guiding function. The calibration section 26 and the cutting section 12 are typically integrally formed.

[0050] like Figure 1 As shown, in an embodiment of the present invention, the internal thread repair tap further includes a shank 28. Along the axial direction of the tap, the cutting part 12, the calibration part 26, and the shank 28 are connected sequentially. An air inlet is formed inside the shank 28. The internal thread repair tap is connected to a tapping device via the shank 28, which may include an automatic tapping machine. The shank 28 has high hardness and wear resistance, and its material is generally spring steel. The shank 28 can be integrally formed with the cutting part 12 and the calibration part 26, or it can be connected by bolts. The air inlet guides the gas flow, allowing it to be blown towards the outside of the chip removal groove 24, thereby blowing away debris inside the threaded hole, preventing chip accumulation, and improving the chip removal effect of the internal thread repair tap.

[0051] like Figure 1 As shown, in an embodiment of the present invention, the shank 28 includes a shank portion 30 and a square tail portion 32; along the axial direction of the tap, the cutting portion 12, the calibration portion 26, the shank portion 30, and the square tail portion 32 are connected in sequence. The square tail portion 32 is used to transmit torque when the internal thread repair tap is working. The shank portion 30 and the square tail portion 32 are usually integrally formed to ensure sufficient strength between the shank portion 30 and the square tail portion 32, and to avoid transmission failure caused by the square tail portion 32 breaking during the rotation of the internal thread repair tap.

[0052] like Figure 3 As shown, a second aspect of the present invention provides a method for manufacturing an internal thread repair tap based on any of the internal thread repair taps in the first aspect embodiment described above, the method comprising:

[0053] Step 100: Grind the cutting part 12 along the tangent 18 of the guide cone to form the guide cone surface 16, wherein the guide cone surface 16 covers N-1 thread teeth 14;

[0054] Step 200: Grind the 1st, 2nd, 3rd, ... Nth thread teeth 14 along the tooth profile outline 15 of the tooth angle, wherein the tooth angle of the thread teeth 14 gradually increases from the first thread tooth 14 to the Nth thread tooth 14.

[0055] Step 300: Grind the rear angle 22 along the rear angle contour line 23 to make the angle of the rear angle 22 negative.

[0056] In step 100, the guide cone tangent 18 can be understood as the projection line of the guide cone surface 16 on the axial section of the internal thread repair tap, wherein the guide cone tangent 18 is tangent to the tip section of each thread tooth 14. In this embodiment, the starting point of the guide cone tangent 18 is connected to the first thread tooth 14, the ending point of the guide cone tangent 18 is connected to the Nth thread tooth 14, the guide cone surface 16 actually covers the first thread tooth 14 to the (N-1)th thread tooth 14, and the guide cone surface 16 is in point contact with the Nth thread tooth 14.

[0057] In step 200, the tooth profile angle of the thread tooth 14 refers to the angle between the two contour surfaces of the thread tooth 14. The tooth profile contour line 15 of the tooth profile angle can be understood as the projection line of the two sides of the thread tooth 14 on the axial section of the internal thread repair tap. The size of the angle between the two projection lines is the size of the tooth profile angle. Figure 1 The difference between the tooth profile 15 in this embodiment of the invention and the standard tooth profile 36 is shown.

[0058] In step 300, the rear angle contour line 23 of the rear angle 22 can be understood as the projection contour of the rear angle 22 on the radial section of the internal thread repair tap. Figure 2 The difference between the rear corner contour line 23 in this embodiment of the invention and the standard rear corner contour line 38 is shown.

[0059] According to the method for manufacturing an internal thread repair tap provided in the second aspect of the present invention, the cutting portion 12, the tooth profile angle of the thread teeth 14, and the clearance angle 22 on the cutting surface 20 of the internal thread repair tap are ground to lengthen the guiding distance of the guide cone surface 16, thereby making it easier for the lead portion of the internal thread repair tap to enter the threaded hole; after grinding, from the first thread tooth 14 to the Nth thread tooth 14, the tooth profile angle of the thread teeth 14 gradually increases, that is, the tooth profile angle of the first thread tooth 14 is smaller than that of the second thread tooth 14, and the second thread tooth 14 is smaller than that of the second thread tooth 14. The tooth profile angle of thread tooth 14 is smaller than that of the third thread tooth 14, and so on. Based on the above structure, the distance between the first thread tooth 14 and the second thread tooth 14 will be greater than the distance between the second thread tooth 14 and the third thread tooth 14, and the distance between the second thread tooth 14 and the third thread tooth 14 will be greater than the distance between the third thread tooth 14 and the fourth thread tooth 14, and so on. The smaller the tooth profile angle of thread tooth 14, the thinner the teeth of thread tooth 14, which makes it easier for the lead part of the internal thread repair tap to enter the threaded hole. Furthermore, the tooth profile angle of the thread tooth 14 gradually transitions from small to large to a standard angle, which improves the fit with the internal thread profile. The thread tooth 14 covered by the guide cone surface 16 is a rectangular thread tooth, and the tooth crest of the thread tooth 14 is lowered, which can avoid extrusion damage to the crest of the deformed internal thread. As the internal thread repair tap is screwed in, the rectangular thread tooth can gradually compress the deformed internal thread, gradually correcting the deformed internal thread to the normal angle and restoring the pitch and tooth profile angle of the deformed internal thread. The back angle 22 after grinding is a negative value, which will not have a shearing effect on the deformed internal thread. It can also change the cutting part 12 of the tap from a cutting state to a compressing state, and push the deformed internal thread in the internal thread groove of the threaded hole, causing it to deform again to restore it to a normal state. In summary, the internal thread repair tap made based on the internal thread repair tap manufacturing method provided in this embodiment of the invention can be more easily introduced into the threaded hole, improve the fit with the internal thread profile, and effectively repair the internal thread.

[0060] A third aspect of the present invention provides an internal thread repair device, including an internal thread repair tap as described in any of the first aspects, or an internal thread repair tap manufactured based on the internal thread repair tap manufacturing method provided in the second aspect.

[0061] Internal thread repair equipment can be small, handheld devices, such as connecting an internal thread repair tap to a ratchet wrench and manually applying rotational force to the tap. Internal thread repair equipment can also be large devices, such as machine tools, where the internal thread repair tap is fixed to a tap holder on the machine tool and driven by a motor to rotate the tap, offering a high degree of automation and good control precision.

[0062] According to the third aspect of the present invention, the internal thread repair device uses an internal thread repair tap. The structure of the cutting part 12 is optimized. Specifically, the internal thread repair tap includes a cutter head 10, which includes a cutting part 12. Threaded teeth 14 and a guide cone surface 16 are formed on the cutting part 12. The guide cone surface 16 is a sloped surface. From the end of the cutting part 12 to the tail of the cutting part 12, the diameter of the cutting part 12 gradually increases. Furthermore, the guide cone tangent 18 of the guide cone surface 16 connects N threaded teeth 14, that is, the guiding distance of the guide cone surface 16 is lengthened, which makes it easier for the lead part of the internal thread repair tap to enter the threaded hole. From the first threaded tooth 14 to the Nth threaded tooth 14... The tooth angle of thread tooth 14 gradually increases, that is, the tooth angle of the first thread tooth 14 is smaller than that of the second thread tooth 14, the tooth angle of the second thread tooth 14 is smaller than that of the third thread tooth 14, and so on. Based on the above structure, the distance between the first thread tooth 14 and the second thread tooth 14 will be greater than the distance between the second thread tooth 14 and the third thread tooth 14, the distance between the second thread tooth 14 and the third thread tooth 14 will be greater than the distance between the third thread tooth 14 and the fourth thread tooth 14, and so on. The smaller the tooth angle of thread tooth 14, the thinner the teeth of thread tooth 14, which makes it easier for the lead part of the internal thread repair tap to enter the threaded hole. Furthermore, the tooth profile angle of the thread tooth 14 gradually transitions from small to large to a standard angle, which can improve the fit with the internal thread profile. The thread tooth 14 covered by the guide cone surface 16 is a rectangular thread tooth. The tooth tip of the thread tooth 14 is lowered, which can avoid extrusion damage to the deformed internal thread tip. As the internal thread repair tap is screwed in, the rectangular thread tooth can gradually extrude the deformed internal thread, gradually correcting the deformed internal thread to the normal angle and restoring the pitch and tooth profile angle of the deformed internal thread. The cutting surface 20 on the thread tooth 14 is a cutting surface used for cutting the workpiece. The cutting surface 20 has a rake angle and a clearance angle 22. The rake angle is located at the front end of the cutting surface 20, and the clearance angle 22 is located behind the rake angle. After grinding, the clearance angle 22 is negative, so it will not shear the deformed internal thread. It also allows the cutting part 12 of the tap to change from a cutting state to a pressing state, pushing the deformed internal thread in the internal thread groove of the threaded hole, causing it to deform again and return to its normal state. In summary, the internal thread repair device provided by this embodiment of the invention optimizes the structure of the cutting part 12, making it easier to introduce the tap into the threaded hole, improving the fit with the internal thread profile, and effectively repairing the internal thread.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tap for repairing internal threads, characterized in that, include: The cutting head (10) includes a cutting part (12) on which threaded teeth (14) and a guide cone surface (16) are formed; The guide cone tangent (18) of the guide cone surface (16) connects to N of the thread teeth (14); From the first threaded tooth (14) to the Nth threaded tooth (14), the tooth profile angle of the threaded tooth (14) gradually increases; A cutting edge (20) is formed on the thread tooth (14), and a clearance angle (22) is formed on the cutting edge (20). The clearance angle (22) is negative, so that when repairing the internal thread, the cutting edge mainly plays a squeezing and correcting role on the deformed internal thread, rather than a cutting role. The calibration section (26) is used to calibrate the size and shape of the thread and serves as a guide.

2. The internal thread repair tap according to claim 1, characterized in that, N is 6, and the tooth profile angle of the first threaded tooth (14) is 43°; The angle of the rear angle (22) is -13°.

3. The internal thread repair tap according to claim 1, characterized in that, The internal thread repair tap also has a chip removal groove (24) formed on it. The chip removal groove (24) extends along the axial direction of the tap, and two adjacent chip removal grooves (24) are connected by the cutting edge (20).

4. The internal thread repair tap according to claim 3, characterized in that, The chip removal groove (24) includes a straight groove or a spiral groove.

5. The internal thread repair tap according to claim 1, characterized in that, A rake angle is formed on the cutting edge (20), and the rake angle is located at the end of the cutting edge (20) that contacts the cutting surface; The angle range of the front angle is 8° to 10°.

6. The internal thread repair tap according to any one of claims 1 to 5, characterized in that, Along the axial direction of the tap, the cutting part (12) and the calibration part (26) are arranged sequentially; The calibration part (26) has the threaded teeth (14).

7. The internal thread repair tap according to claim 6, characterized in that, The internal thread repair tap also includes a tool holder (28), and the cutting part (12), the calibration part (26), and the tool holder (28) are connected in sequence along the axial direction of the tap; An air supply hole is formed inside the handle (28).

8. The internal thread repair tap according to claim 7, characterized in that, The handle (28) includes a handle portion (30) and a square tail portion (32); Along the axial direction of the tap, the cutting part (12), the calibration part (26), the shank part (30) and the square tail part (32) are connected in sequence.

9. A method for manufacturing an internal thread repair tap based on any one of claims 1 to 8, characterized in that, include: The cutting portion (12) is ground along the tangent (18) of the guide cone to form the guide cone surface (16), wherein the guide cone surface (16) covers N-1 of the thread teeth (14); The first, second, third, ... Nth threaded teeth (14) are ground along the tooth profile outline (15) of the tooth angle, wherein the tooth angle of the threaded teeth (14) gradually increases from the first threaded tooth (14) to the Nth threaded tooth (14); The rear angle (22) is ground along the rear angle contour line (23) to make the angle of the rear angle (22) negative.

10. An internal thread repair device, characterized in that, Includes internal thread repair taps as described in any one of claims 1 to 8, or internal thread repair taps manufactured based on the internal thread repair tap manufacturing method described in claim 9.

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