A double negative wedge angle tooth profile grinding process suitable for ordinary profile grinding machines

Abstract

This invention relates to the field of grinding technology and discloses a double negative wedge angle tooth profile grinding process suitable for ordinary profile grinding machines, comprising the following steps: S1: Mounting the workpiece blank on an ordinary profile grinding machine using a first fixture and a second fixture; S2: Grinding a 0-angle tooth portion using a rough grinding wheel; S3: Rotating the first fixture clockwise and counterclockwise by a first angle respectively, and using a side-feed method with the rough grinding wheel to perform side clearance angle roughing on the left and right sides of the tooth respectively; S4: Rotating the first fixture clockwise and counterclockwise by a second angle respectively to form a positive angle, and using a fine grinding wheel to perform step-by-step fine grinding on the left and right sides of the tooth with two reciprocating cuts; the fine grinding order of the left and right sides of the tooth can be changed; S5: After the left and right sides of the tooth are finished in sequence, the tool is connected at the tooth tip; S6: After fine grinding, a tooth width allowance is reserved, and the rake face is opened; This solves the technical problem that double negative wedge angle grinding and machining of double negative wedge angle tools cannot be performed on ordinary profile grinding machines.

Description

Technical Field

[0001] This invention relates to the field of grinding technology, and specifically to a double negative wedge angle tooth profile grinding process applicable to ordinary profile grinding machines. Background Technology

[0002] To adapt to more complex underground or subsea geological environments, domestic and international oil drilling and production companies have been introducing double negative wedge angle thread types with constant tooth width (such as...) in recent years. Figure 1 To produce the aforementioned double negative wedge angle thread type, a corresponding double negative wedge angle cutting tool must be used. The widest part of the tooth tip of the double negative wedge angle cutting tool must be smaller than the narrowest tooth profile of the part (e.g., ...). Figure 2 The thread turning is completed by using straight feed and left and right feed methods.

[0003] With the widespread use of double negative wedge angle threaded joints, the demand for double negative wedge angle cutting tools is increasing. However, double negative wedge angle cutting tools differ from traditional threading tools, and the difficulties in their manufacturing include: 1) When the bearing surface and guide surface of the tooth of a traditional threading tool are both at positive angles, the tool, workpiece, and grinding wheel do not need to be rotated during dressing, and the entire tooth can be ground directly (e.g., Figure 3 Traditional thread cutting tools, when the guide surface of the tooth is at a positive angle and the bearing surface is at a negative angle, require the grinding wheel to be rotated to a positive angle for dressing due to hardware limitations. The fixture also needs to rotate accordingly during grinding. However, it is possible to complete whole-tooth grinding (e.g., ...). Figure 4 , Figure 5 However, the double negative wedge angle tool has negative angles on both sides of the tooth, and no matter how it rotates, one side will always have a negative angle, making it impossible to dress the grinding wheel and preventing full-tooth grinding using existing processes; 2) Even if a grinding method is found, due to... Figure 2 Due to width limitations, the cutting tool teeth have a narrowest section, with allowances at any of the three positions: tooth tip, tooth flank, and tooth root (e.g., ...). Figure 6 1) Too large an angle, which will cause cracks or even breakage during conventional grinding; 2) A long step surface exists on one side of the tooth of the double negative wedge angle tool (e.g., Figure 7 ), used for connecting adjacent threads, but due to the excessive length of the straight line, after conventional grinding with existing grinding wheels, the straight line shape is poor and the grinding marks on the stepped surface are heavy, which cannot meet the usage requirements; 4) The side back face of the double negative wedge angle thread tool is prone to interference during the machining process, so it is necessary to machine a side back angle of 3-4°. Machining the side back angle on a conventional grinding machine will produce a 0.1-0.2mm wide cutting edge. When opening the rake face, it will also cause the tool tooth width to become narrower, which cannot meet the usage requirements.

[0004] To address the aforementioned technical challenges, existing processes cannot directly utilize conventional profile grinding machines to manufacture these types of tools. Consequently, tool manufacturers that rely solely on conventional profile grinding machines are forced to employ wire EDM or even five-axis CNC machine tools for production. This significantly raises the production threshold and manufacturing costs, hindering technological development from being supported by production applications and impeding the growth of tool manufacturers and the entire industry. Summary of the Invention

[0005] The present invention aims to provide a double negative wedge angle tooth profile grinding process applicable to ordinary profile grinding machines, in order to solve the technical problem that double negative wedge angle tools cannot be directly manufactured using ordinary profile grinding machines using existing process methods.

[0006] The basic solution provided by this invention is: a double negative wedge angle tooth profile grinding process suitable for ordinary profile grinding machines, comprising the following steps:

[0007] S1: Using the first fixture, the workpiece blank is mounted on the ordinary forming grinding machine A;

[0008] S2: Use a coarse grinding wheel to grind out the 0-angle teeth, leaving a fine grinding allowance at the tooth tip and tooth bottom, and a coarse grinding allowance on the left and right sides of the teeth;

[0009] S3: Using the second fixture, install the finished blank processed in the previous step onto the ordinary forming grinder B;

[0010] S4: By rotating the second fixture to form the first angle, use a coarse grinding wheel to perform rough machining of the lateral rear angle on the left and right sides of the tooth respectively, removing most of the excess material, and leaving fine grinding allowance on both the left and right sides of the tooth;

[0011] S5: Using the first fixture and the guide block 1 fixedly installed on the first fixture, the finished blank processed in the previous step is installed on the ordinary forming grinder A. The first fixture is rotated clockwise to the second angle to form a positive angle. The left side of the teeth is finely ground stepwise by two reciprocating cuts using a fine grinding wheel.

[0012] S6: Using the first fixture and the second guide block fixedly installed on the first fixture, the finished blank processed in the previous step is installed on the ordinary forming grinder A. The first fixture is rotated counterclockwise to the second angle to form a positive angle. The right side of the tooth is finely ground by two reciprocating cuts of the fine grinding wheel.

[0013] S7: After the left and right sides of the tooth are finely ground in sequence, a tool joint is formed at the tooth tip;

[0014] S8: After fine grinding, a tooth width allowance is reserved for the front face opening;

[0015] Both guide block one and guide block two have a third angle, which is used to complete the fine grinding of the lateral rear angle while the tooth side is finely ground; the order of S5 and S6 can be changed.

[0016] The working principle and advantages of this invention are as follows: Compared with the prior art, it overcomes the technical problem that existing processes cannot directly use ordinary profile grinding machines to process and manufacture double negative wedge angle tools, and realizes the process method of grinding double negative wedge angles on ordinary profile grinding machines, achieving correct tooth profile dimensions, slight tool contact marks at the tooth tip, and simultaneous grinding of the side clearance angle and tooth profile.

[0017] To overcome the limitation of coarse grinding wheels in forming a double negative wedge angle, the tooth is directly ground at a 0-angle angle. Most of the allowance at the tooth tip and root is ground simultaneously, leaving room for fine grinding. Since the most critical part of the double negative wedge angle tooth shape is the grinding of both sides of the tooth, a rough grinding allowance is first reserved, and a second rough grinding is required. The back angle of both sides of the tooth is roughened while the second rough grinding is completed, leaving room for fine grinding. Then, the two sides of the tooth are finely ground in a step-by-step manner on one side. The positive angle is formed by rotating the fixture, which can adapt to the hardware limitations of ordinary profile grinding wheels. After fine grinding, the double negative wedge angle tooth shape is completed by opening the rake face.

[0018] Removing excess grinding material from the tooth tip, tooth root, and tooth flank is a crucial step in achieving double negative wedge angle grinding. Through the process steps of this invention, all of these steps can be achieved on a conventional grinding machine. At the same time, by using a step-by-step single-sided fine grinding method, the surface quality of the long step of the tool is improved, thereby enhancing the tool quality.

[0019] Furthermore, in S4, the finishing allowance on both the left and right sides of the tooth is controlled at 0.1mm; in S6, the reciprocating two-cut step finishing is as follows: the depth of cut of the first cut is controlled within the range of 0.04-0.06mm, and the depth of cut when the grinding wheel retracts is controlled at 0.05mm.

[0020] Beneficial effects: The 0.1mm fine grinding allowance design is effective in most form grinding processes, but it is not enough for the long straight edge of double negative wedge angle tools. Therefore, the reciprocating two-cut step-by-step fine grinding process proposed in this invention is adopted. The first cut is about 0.05mm deep, and the grinding wheel cuts another 0.05mm deep when it retracts, which significantly improves the surface finish.

[0021] Furthermore, in S2, the grinding of the 0-angle tooth is performed in three passes, with the depth of cut of the last pass controlled at 0.5mm. In S2, a 0.1mm finishing allowance is left at both the tooth tip and the tooth root, while the rough grinding allowance on the left and right sides of the tooth is controlled within the range of 0.1-0.2mm.

[0022] Beneficial effects: Setting the allowance at the tooth tip, tooth flank, and tooth root positions relatively evenly avoids excessive allowance in one area, which could cause support misalignment during grinding, resulting in cracks or even breakage, thus improving grinding quality. Furthermore, rough grinding directly completes the machining of the tooth tip and tooth root, while leaving rough grinding allowance on the left and right sides of the tooth. This provides sufficient and appropriate grinding allowance for subsequent multiple machining operations on the two tooth flanks, improving the quality of tool machining.

[0023] Furthermore, in S4, the lateral rearward angle is controlled within the range of 3-4°.

[0024] Beneficial effect: Avoids interference on the side and back face of double negative wedge angle thread cutting tools during machining.

[0025] Furthermore, the double negative wedge angle is 6°30′, the first angle is 7°, the second angle is 9°, the positive angle is 2°30′, the third angle is 3°30′, and the tooth width margin is 0.025mm.

[0026] Beneficial effects: The combination of this size set enables the production of high-quality cutting tools with accurate tooth profile dimensions and minimal tool marks at the tooth tips. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a double negative wedge angle thread type in the prior art;

[0028] Figure 2 This is a schematic diagram of the structure of the tooth section of a double negative wedge angle cutting tool and the narrowest tooth profile of the workpiece in the prior art;

[0029] Figure 3 This is a schematic diagram of the structure of the tooth section (both the bearing surface and the guide surface are at positive angles) of a traditional thread cutting tool in the prior art;

[0030] Figure 4 This is a schematic diagram of the structure of the tooth section of a traditional thread cutting tool in the prior art (the guide surface is at a positive angle and the bearing surface is at a negative angle);

[0031] Figure 5 for Figure 4 A schematic diagram of the structure rotated by 6°;

[0032] Figure 6 This is a schematic diagram showing the main allowance of the teeth in a double negative wedge angle cutting tool in the prior art;

[0033] Figure 7 This is a schematic diagram showing the position of the long step surface and step line of the tooth in a double negative wedge angle cutting tool in the prior art;

[0034] Figure 8 A flowchart of a double negative wedge angle tooth profile grinding process applicable to a conventional profile grinding machine is provided in an embodiment of the present invention;

[0035] Figure 9 This is a front view of the workpiece blank for the double negative wedge angle tool provided in an embodiment of the present invention;

[0036] Figure 10 This is a schematic diagram of a fixture holding a workpiece blank according to an embodiment of the present invention;

[0037] Figure 11 This is a schematic diagram of the structure of the 0-angle tooth section of the coarse grinding wheel provided in an embodiment of the present invention;

[0038] Figure 12 This is a diagram showing the allowance distribution of a workpiece after rough grinding, provided in an embodiment of the present invention.

[0039] Figure 13 This is a schematic diagram of the coarse grinding tooth side provided in an embodiment of the present invention;

[0040] Figure 14 This is a schematic diagram of the left side of the precision-ground tooth provided in an embodiment of the present invention;

[0041] Figure 15 This is a schematic diagram of the right side of the precision-ground tooth provided in an embodiment of the present invention;

[0042] Figure 16 This is a schematic diagram of the rotation of the second clamp provided in an embodiment of the present invention;

[0043] Figure 17 This is a schematic diagram of the second clamp after rotation provided in an embodiment of the present invention;

[0044] Figure 18 This is a schematic diagram of the dimensions of the rake face provided in an embodiment of the present invention;

[0045] Figure 19 This is a schematic diagram showing the dimensions reserved for the tooth width in an embodiment of the present invention. Detailed Implementation

[0046] The following detailed explanation illustrates the specific implementation methods:

[0047] The markings in the accompanying drawings include: 1. Double negative wedge angle thread type; 2. Narrowest tooth profile of the part; 3. Double negative wedge angle tooth; 31. Tooth tip; 32. Tooth root; 33. Left side of tooth; 34. Right side of tooth; 4. Bearing surface; 5. Guide surface; 6. Tooth tip allowance; 7. Tooth root allowance; 8. Tooth flank allowance; 9. Long step surface; 10. Long step line; 11. Workpiece blank; 12. Rough grinding wheel; 13. 0-angle tooth; 14. Blank allowance; 15. First rough grinding allowance; 16. Tooth flank rough grinding; 17. Tooth flank fine grinding; 18. Fine grinding wheel; 19. Adjacent peripheral line; 20. Cutting edge; 21. Feed direction; 22. Rake face; 23. First clamp; 24. Guide block; 25. Clamping block.

[0048] Example 1

[0049] The basic implementation examples are as follows: Figure 8 As shown: A double negative wedge angle tooth profile grinding process suitable for ordinary profile grinding machines includes the following steps:

[0050] S1: Using the first fixture 23, the workpiece blank 11 is mounted on the ordinary forming grinding machine A;

[0051] S2: Use coarse grinding wheel 12 to grind out the 0-angle teeth. Leave fine grinding allowance for the tooth top 31 and tooth bottom 32, and leave coarse grinding allowance for the left side 33 and right side 34.

[0052] S3: Using the second fixture, install the finished blank processed in the previous step onto the ordinary forming grinder B;

[0053] S4: By rotating the second fixture to form the first angle θ1, the rough grinding wheel 12 is used to perform lateral rear angle roughing on the left side 33 and the right side 34 of the tooth respectively to remove most of the excess material, and leave fine grinding allowance on both the left side 33 and the right side 34 of the tooth.

[0054] S5: Using the first fixture 23 and the guide block 24 fixedly installed on the first fixture 23, the finished blank processed in the previous step is installed on the ordinary forming grinder A. The first fixture 23 is rotated clockwise at the second angle θ2 to form a positive angle θ3. The left side 33 of the gear is finely ground by two reciprocating cuts of the fine grinding wheel 18.

[0055] S6: Using the first fixture 23 and the guide block 24 fixedly installed on the first fixture 23, the finished blank processed in the previous step is installed on the ordinary forming grinder A. The first fixture 23 is rotated counterclockwise at the second angle θ2 to form a positive angle θ3. The right side 34 of the gear is finely ground by two reciprocating cuts of the fine grinding wheel 18.

[0056] S7: After the left side 33 and the right side 34 of the tooth are finished by precision grinding, a tool connection is formed at the tooth tip 31;

[0057] S8: After fine grinding, a tooth width allowance is reserved for opening the front face 22;

[0058] Both guide block one and guide block two have a third angle θ4, which is used to finish the fine grinding of the tooth side and the fine grinding of the lateral rear angle at the same time; the order of S5 and S6 can be changed.

[0059] This embodiment uses the machining of a 6°30′ double negative wedge angle tool on a common profile grinding machine such as MM7132 or MM7120 as an example. In this embodiment, clockwise and counterclockwise rotation are both based on the vertical axis of the center hole of the double negative wedge angle tool, which is the plane of rotation when the reader looks at the attached figure. The fixture only needs to be able to achieve the clamping function and positioning requirements of this solution, and no specific structural limitations are made here.

[0060] S1 performs blank clamping, specifically, as follows: Figure 9 The triangular workpiece blank 11 shown has an inscribed circle diameter of 15.875 mm. It is clamped on a conventional forming grinder A using the first fixture 23, which can perform rough grinding on at least 12 cutting tools at a time, resulting in high processing efficiency.

[0061] S2 performs rough grinding, specifically, as follows: Figure 11 As shown, for the 0-angle tooth 13, the grinding shape of the rough grinding wheel 12 cannot form a double negative wedge angle, so it is directly ground with the 0-angle shape 13. Since the workpiece blank 11 at the triangular part has a large allowance after machining from the triangular workpiece to the 00-angle tooth 13, in order to improve the rough grinding accuracy and avoid cracks or fractures caused by the difference in allowance, three unidirectional passes are reasonably performed. In the first pass, the pass speed is controlled at 8m / min, the depth of cut is controlled at 1.0-1.2mm, the tooth tip allowance 6 is controlled at 1.3-1.5mm, and the tooth root allowance 7 is controlled at 1.3-1.5mm; in the second pass, the pass speed is controlled at 8m / min, the depth of cut is controlled at 0.8-1.0mm, the tooth tip allowance 6 is controlled at 0.3-0.7mm, and the tooth root allowance 7 is controlled at 0.3-0.7mm; in the third pass, the pass speed is controlled at 12m / min, and the depth of cut is controlled at 0.5mm. Figure 12 As shown, the fine grinding allowances d1 and d2 for the tooth top 31 and tooth bottom 32 are 0.1mm, respectively, while the rough grinding allowance d3 for the tooth left side 33 and tooth right side 34 is controlled within the range of 0.1-0.2mm.

[0062] The above three-pass method, as well as the pass speed, depth of cut, and allowance for each pass, are all within a reasonable range and have appropriate differences. This ensures that the workpiece blank 11 is of high quality when the two passes are connected, thus improving machining accuracy. At the same time, it can be completed by conventional grinding on a regular profile grinding machine, thus improving versatility.

[0063] like Figure 12 As shown, after the first rough grinding removes the blank allowance 14, the machining of the tooth tip 31 and tooth root 32 is completed directly, leaving a corresponding fine grinding allowance. At the same time, the left side 33 and right side 34 of the tooth are reserved for rough grinding, as shown in the first rough grinding allowance part 15, waiting for the second rough grinding of the tooth side.

[0064] S3 uses the second fixture to mount the finished blank processed in the previous step onto the ordinary forming grinding machine B; then performs grinding by switching grinding machines, overcoming the limitation that a single grinding machine cannot process threaded tools with variable tooth widths, and creatively discovering that special threaded tools can be ground by switching between two ordinary grinding machines.

[0065] S4 performs rough machining of the lateral angles of tooth 33 on the left side and tooth 34 on the right side, which is a secondary rough grinding of both sides of the tooth. Figure 13As shown, most of the material removed by grinding is the rough grinding part 16 on the tooth side, and the reserved material for fine grinding on the tooth side is the fine grinding part 17 on the tooth side. Specifically, the rough grinding wheel 12 is used for grinding. The second fixture is rotated clockwise at the first angle θ1, which can be taken as 7°, to perform rough grinding on the left side 33 of the tooth with a lateral back angle. Two passes are made at a speed of 10m / min, with each pass being 0.2-0.3mm. The lateral back angle is controlled within 3-4°, and the fine grinding allowance is controlled within 0.1mm. The second fixture is then returned to center and checked. The second fixture is rotated counterclockwise at the first angle θ1, which can be taken as 7°, to perform rough grinding on the left side 33 of the tooth with a lateral back angle. Two passes are made at a speed of 10m / min, with each pass being 0.2-0.3mm. The lateral back angle is controlled within the range of 3-4°, and the fine grinding allowance is controlled within 0.1mm. d4 is the tooth groove width of the double negative wedge angle tool, and d5 is the rough grinding groove width.

[0066] The above process creates a 7-8° side relief face on the two tooth sides after rough grinding. The roughing of the side relief angle and the grinding of the tooth profile are carried out simultaneously, which avoids the problem of interference between the side relief face and the double negative wedge angle thread tool during the machining process, and also performs tooth profile machining at the same time, thus improving the machining efficiency.

[0067] S5 and S6 are precision ground on one side of both sides of the teeth, such as Figure 14 and Figure 15 As shown, the fine grinding wheel 18 is used for fine grinding in two reciprocating strokes on one side each time, and the order of S5 and S6 can be changed.

[0068] Specifically, S5: such as Figure 10 As shown, using the first clamp 23 and the guide block 24 fixedly installed on the first clamp 23, the finished blank processed in the previous step is installed on the ordinary forming grinder A, and clamped by the clamping block 25. The first clamp 23 is rotated clockwise to the second angle θ2 to form a positive angle θ3. The left side 33 of the tooth is finely ground by the two reciprocating cuts of the fine grinding wheel 18.

[0069] S6: Using the first clamp 23 and the guide block 24 fixedly installed on the first clamp 23, the finished blank processed in the previous step is installed on the ordinary forming grinder A, and clamped with the clamping block 25. The first clamp 23 is rotated counterclockwise at the second angle θ2 to form a positive angle θ3. The right side 34 of the tooth is finely ground by two reciprocating cuts of the fine grinding wheel 18.

[0070] Specifically, such as Figure 14 As shown, rotating the first clamp 23 clockwise by the second angle θ2 can be taken as 9°, forming a positive angle θ3, which can be taken as 2°30′. At the same time, the guide block 24 has its own third angle θ4, as shown. Figure 16 and Figure 17As shown, the tooth can be rotated clockwise by a third angle θ4, which can be 3°30′ or 3°50′, using a reciprocating two-cut fine grinding wheel 18. The fine grinding allowance of the left side 33 of the tooth in S3 is controlled at 0.1mm. The reciprocating two-cut fine grinding is as follows: the depth of cut of the first cut is controlled in the range of 0.04-0.06mm, and the depth of cut when the grinding wheel retracts is controlled at 0.05mm. The feed speed is 12m / min. The allowance of the fine grinding part 17 on the tooth side is finely ground away, and the cutting edge of the cutting edge part 20 is removed at the same time to improve the quality of the tool. The feed direction 21 is perpendicular to the axis.

[0071] Return the first clamp 23 to its correct position and inspect it; replace the guide block 24. Figure 15 As shown, rotate the first fixture 23 counterclockwise, with the same angles as above, and the feed rate is 12m / min; the fine grinding sequence of the left side 33 and the right side 34 of the tooth can be changed.

[0072] Based on single-sided fine grinding, by adjusting the angle of the first fixture 23, the side being finely ground can always be at a positive angle θ3, making it possible for ordinary grinding machines to perform grinding. At the same time, by using the third angle θ4 provided by the guide blocks 24-1 and 24-2, the fine grinding of the side back angle is completed simultaneously with the fine grinding of the tooth side. After grinding by the grinding wheel, a side back angle without a cutting edge is produced, which meets the requirements for use and forms a qualified tool tooth.

[0073] S7: After the left side 33 and the right side 34 of the tooth are finished by precision grinding, a tool connection is formed at the tooth tip 31; the tool connection method is existing technology and will not be described in detail here.

[0074] S8 is used to open the front face to form a qualified tooth profile. Specifically, machining the front face 22 will cause a change in the tool tip height, such as... Figure 18 As shown, the diameter was reduced from 6.35mm to 6.15mm. Figure 19 (The difference between the two is 0.2mm). In addition, the tool has a 3-4° lateral clearance angle on both sides, which will reduce the tooth width and cause deviations from tolerance. Therefore, if... Figure 19 As shown, the tooth width of the fine-ground tooth profile can be pre-widened by 0.025mm, which can prevent the tooth width from becoming smaller. That is, after fine grinding, a tooth width allowance of 0.025mm is reserved, and the rake face 22 is opened to directly process the qualified tooth profile.

[0075] The double negative wedge angle, the first angle θ1, the second angle θ2, the positive angle θ3, the third angle θ4, and the tooth width allowance are set by preset ratios to improve the versatility of this process method and quickly determine the selection of machining data for more models of double negative wedge angle tools. The specific representation of each angle is as in Example 1, and will not be explained in detail here.

[0076] Table 1. Dimensional Data for Double Negative Wedge Angle Cutting Tools

[0077] Double negative wedge angle First angle Second angle positive angle Third angle Tooth width allowance -3° 7° 6° 3° 3.5° 0.025mm

[0078] The value of the double negative wedge angle is determined by market demand and is closely related to the second angle in the fine-ground tooth profile. Generally speaking, the second angle should turn the negative wedge angle from negative to positive to 3°, that is, the second angle = 3° - the number of negative wedge angles.

[0079] The first angle is related to the third angle. Generally speaking, the third angle of a double negative wedge angle tool is 3.5°. Therefore, when the rough grinding tooth side allowance is 8, it is given to 7°, which can remove most of the allowance.

[0080] The tooth width allowance is related to the first angle and the third angle. When the first angle and the third angle are fixed at 7° and 3.5° respectively, the tooth width allowance is 0.025mm.

[0081] This embodiment provides a double negative wedge angle tooth profile grinding process suitable for ordinary profile grinding machines. It overcomes the technical difficulty that existing double negative wedge angle special thread tool machining cannot be performed on ordinary profile grinding machines and can only be completed using high-precision equipment, resulting in a high barrier to entry for tool machining. After detailed research on the double negative wedge angle tooth profile structure and the existing high-precision equipment machining process, this solution found that the obstacle preventing the machining of the aforementioned special tooth profile on ordinary profile grinding machines lies in the conflict between the double negative angle of the tooth profile and the hardware limitation that ordinary grinding machine grinding wheels can only form positive angles. The conventional thinking of ordinary tool manufacturers is limited to a single machining method on a single grinding machine, thus failing to resolve this conflict. The biggest difference between this solution and existing technologies is that it breaks through conventional thinking and optimizes the entire double negative wedge angle tooth profile machining process. The process does not require precision equipment to complete the process in one go. Instead, based on the limitations of the grinding wheel hardware, the entire processing is divided into segments. It creatively proposes to first grind the 0-angle tooth part, then perform two single-sided grindings. Furthermore, during the two single-sided grindings, a process innovation is proposed to grind the side clearance angle and the tooth profile simultaneously. The entire process is carried out by switching between two ordinary profile grinding machines. Through the orderly switching of grinding machines and the special rotation of the fixture, it is not only possible to perform double negative wedge angle grinding on ordinary profile grinding machines, but also to achieve a high-quality double negative wedge angle tooth profile machining process with correct tooth profile dimensions, minimal tool marks at the tooth tip, and high quality. This greatly lowers the processing threshold for double negative wedge angle tooth profile tools, which is conducive to promoting the production efficiency of tool manufacturers and the development of technologies such as thread structure and thread processing.

[0082] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics of the solutions are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A double negative wedge angle tooth profile grinding process suitable for ordinary profile grinding machines, characterized in that, Includes the following steps: S1: Using the first fixture, the workpiece blank is mounted on the ordinary forming grinding machine A; S2: Use a coarse grinding wheel to grind out the 0-angle teeth, leaving a fine grinding allowance at the tooth tip and tooth bottom, and a coarse grinding allowance on the left and right sides of the teeth; S3: Using the second fixture, install the finished blank processed in the previous step onto the ordinary forming grinder B; S4: By rotating the second fixture to form the first angle, use a coarse grinding wheel to perform rough machining of the lateral rear angle on the left and right sides of the tooth respectively, removing most of the excess material, and leaving fine grinding allowance on both the left and right sides of the tooth; S5: Using the first fixture and the guide block 1 fixedly installed on the first fixture, the finished blank processed in the previous step is installed on the ordinary forming grinder A. The first fixture is rotated clockwise to the second angle to form a positive angle. The left side of the teeth is finely ground stepwise by two reciprocating cuts using a fine grinding wheel. S6: Using the first fixture and the second guide block fixedly installed on the first fixture, the finished blank processed in the previous step is installed on the ordinary forming grinder A. The first fixture is rotated counterclockwise to the second angle to form a positive angle. The right side of the tooth is finely ground by two reciprocating cuts of the fine grinding wheel. S7: After the left and right sides of the tooth are finely ground in sequence, a tool joint is formed at the tooth tip; S8: After fine grinding, a tooth width allowance is reserved for the front face opening; Both guide block one and guide block two have a third angle, which is used to complete the fine grinding of the lateral rear angle while the tooth side is being finely ground; the order of S5 and S6 can be changed; The double negative wedge angle is 6°30′, the first angle is 7°, the second angle is 9°, the positive angle is 2°30′, the third angle is 3°30′, and the tooth width margin is 0.025mm.

2. The double negative wedge angle tooth profile grinding process applicable to ordinary profile grinding machines according to claim 1, characterized in that, In S4, the finishing allowance on both the left and right sides of the tooth is controlled at 0.1mm; in S6, the reciprocating two-cut step finishing is as follows: the depth of cut of the first cut is controlled within the range of 0.04-0.06mm, and the depth of cut when the grinding wheel retracts is controlled at 0.05mm.

3. The double negative wedge angle tooth profile grinding process applicable to ordinary profile grinding machines according to claim 1, characterized in that, In S2, the 0-angle tooth section is ground in three cuts, with the depth of cut of the last cut controlled at 0.5mm.

4. The double negative wedge angle tooth profile grinding process applicable to ordinary profile grinding machines according to claim 1, characterized in that, In S2, a 0.1mm fine grinding allowance is left at both the tooth tip and tooth bottom, while the rough grinding allowance on the left and right sides of the tooth is controlled within the range of 0.1-0.2mm.

5. The double negative wedge angle tooth profile grinding process applicable to ordinary profile grinding machines according to claim 1, characterized in that, In S4, the lateral rearward angle is controlled within the range of 3-4°.

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