Variable fluted thread cutting tool and cutting method

Abstract

The present application relates to the technical field of thread processing, and discloses a variable thread width thread cutting tool, which comprises a tool main body, a fixing hole is formed in the center of the tool main body, three installation base surfaces which are 60 degrees apart from each other are arranged on the tool main body, and three chip breaking grooves which are 60 degrees apart from each other are also arranged on the tool main body; each chip breaking groove is provided with a cutting tooth on the outer edge thereof; the included angle between the guide surface and the bearing surface and the tooth profile reference horizontal axis is the same; the tooth top plane and the right bottom plane are parallel to the tooth profile reference horizontal axis; the first included angle exists between the left bottom plane and the tooth profile reference horizontal axis; the guide surface and the bearing surface both have a lateral angle which is greater than the helix angle of the thread; the guide surface and the bearing surface can be cut twice, the tool has the advantages of simple and ingenious structure, convenient processing, high positioning precision, transposition switching use, improved production efficiency, high universality, and the ability to meet the use requirements of various variable thread width wedge thread turning.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thread processing, in particular to a variable thread width thread cutting tool and a cutting method. BACKGROUND

[0002] In the design of the connecting parts of mechanical equipment, the fastening mode of bolt and nut cooperation is widely used, which has low cost, flexible installation and wide application range. The traditional thread is equal thread width thread, which can meet the connection requirements. However, this connection mode is easy to cause the fastener to loosen, so in order to solve this problem, engineers in the industry have redesigned the geometry of the nut thread and optimized the design of the variable thread width wedge thread. The tip of the bolt is tightly fixed on the wedge slope of the thread, thereby generating a large locking force, and the bolt and nut can be tightened with each other, thereby fundamentally solving the problem of fastener loosening. With the continuous development of thread processing and manufacturing technology, the thread structure is gradually enriched, and more and more special threads appear.

[0003] In the existing industrial manufacturing field, most thread processing enterprises basically use traditional thread processing forming tools to process some equal thread width threads (the bearing surface and guide surface of the thread have and only one angle is negative angle). Special thread is a product with high technical content, and the special processing forming tool has very high requirements and great processing difficulty. Its structure design and processing technology still belong to commercial secrets. Even if some domestic enterprises have mastered the corresponding technology, for most enterprises, the design foundation is weak, and there is a lack of corresponding processing forming tools. For example, the variable thread width wedge thread with special-shaped face at the top has straight line and arc connection at the top, and the thread bearing surface and guide surface are both negative angle. The traditional tool cannot be processed according to the traditional tool, which seriously hinders the development of most thread processing enterprises. SUMMARY

[0004] The present application aims to provide a variable thread width thread cutting tool and a cutting method to solve the technical problem that the existing thread processing forming tool cannot process the variable thread width wedge special thread.

[0005] The basic solution provided by this invention is as follows: a variable width thread cutting tool, comprising a tool body, a fixing hole at the center of the tool body, three mounting base surfaces at 60 degrees to each other on the tool body, and three chip breaker grooves with an included angle of 60 degrees on their extended lines; each chip breaker groove has a cutting tooth on its outer edge; the cutting tooth, from left to right, is as follows: left bottom plane, left bottom arc surface, guide surface, left top arc surface, tooth top plane, right top arc surface, bearing surface, right bottom arc surface, and right bottom plane; the guide surface and bearing surface have the same angle with the horizontal axis of the tooth profile reference; the tooth top... The left bottom plane and the right bottom plane are both parallel to the horizontal axis of the tooth profile reference; the left bottom plane has a first included angle with the horizontal axis of the tooth profile reference; the guide surface and the bearing surface both have a lateral angle greater than the helix angle of the thread; the central angle of the left bottom arc surface is the same as the included angle between the left bottom plane and the guide surface; the central angle of the left top arc surface is the same as the included angle between the tooth top plane and the guide surface; the central angle of the right top arc surface is the same as the included angle between the tooth top plane and the bearing surface; the central angle of the right bottom arc surface is the same as the included angle between the right bottom plane and the guide surface.

[0006] The working principle and advantages of this invention are as follows: The improved tool structure features three replaceable, indexable cutting teeth. Wear allows for timely indexing and replacement, ensuring the continuity of the entire machining process. Furthermore, it offers a longer tool life than a single cutting tooth, reducing tool costs. Since the variable tooth width is program-controlled, the function of the cutting teeth is simplified, resulting in a more regular and simpler overall shape and reduced cutting difficulty. The guide surface and bearing surface share the same angle with the tooth profile reference horizontal axis, and the tooth tip plane is parallel to the reference axis, facilitating accurate positioning and rapid installation. This makes thread inspection convenient and the calculation of the thread control quantity faster. Both the guide surface and bearing surface have lateral angles, preventing interference between the back side of the thread cutting tool tooth profile and the workpiece. This allows the cutting teeth to perform cutting functions from both sides, increasing torque resistance. The common rake face greatly simplifies tool design. The left bottom plane has a first angle with the tooth profile reference horizontal axis, which, in conjunction with other structures, makes the cutting amount more reasonable, resulting in less cutting redundancy than existing technologies and reducing material waste.

[0007] Compared with existing thread cutting tools, it overcomes the difficulty of existing thread cutting tools not being able to meet the needs of variable width thread machining. It has the advantages of ingenious structure, simple structure, convenient machining, fast clamping, high positioning accuracy, indexable switching, improved production efficiency, high versatility, and can meet the requirements of turning various variable width wedge threads.

[0008] Furthermore, the angle between the guide surface and the bearing surface and the horizontal axis of the tooth profile reference is controlled within the range of 85-80 degrees.

[0009] Beneficial effect: the selection of this range has high adaptability.

[0010] Further, the first included angle is controlled within the range of 5-12 degrees.

[0011] Beneficial effect: the selection of this range is adapted to other structures, and can significantly improve the tool connection strength and over-torque performance.

[0012] Further, the lateral angles of the guide surface and the bearing surface are the same.

[0013] Beneficial effect: the angle size depends on the size of the pitch P and the thread diameter d, and the angle is greater than arcTan(P / πd), which can adapt to special variable width thread machining with the same lateral angle.

[0014] Further, the lateral angles of the guide surface and the bearing surface are different.

[0015] Beneficial effect: the angle size depends on the size of the pitch P and the thread diameter d, and the angle is greater than arcTan(P / πd), which can adapt to special variable width thread machining with different lateral angles.

[0016] Further, the lateral angle is controlled within the range of 2-4 degrees.

[0017] Beneficial effect: the selection of this range can meet the requirement of greater than arcTan(P / πd), and has high adaptability.

[0018] Further, the tool tip height of the tool is smaller than the thickness of the tool, and the difference is controlled within the range of 0.15-3mm.

[0019] Beneficial effect: improves cutting force and tool strength and durability.

[0020] Further, the vertical height of the guide surface tooth height is greater than the vertical height of the bearing surface tooth height.

[0021] Beneficial effect: forms different pitches and tapers of threads.

[0022] Based on the variable width thread cutting tool, the application also provides a variable width thread cutting method to solve the technical problem that the existing thread machining forming tool cannot machine special variable width wedge threads.

[0023] The method comprises the following steps:

[0024] S1: connect the eccentric screw installed in the cutting tool fixing hole with the turning tool rod of the numerical control lathe, and then press the tool by the pressing plate, wherein the screw hole is deviated from the tool center hole by 0.2mm;

[0025] S2: the rake face and the circular arc together form a chip breaker groove for turning the variable width wedge thread, the rake face is placed in the horizontal plane, so that the rake face of the tool is on the center line of the workpiece, and the tolerance is controlled within the range of ±0.15mm;

[0026] S3: the machine tool program sets the control of the change of the width of the thread;

[0027] S4: the bearing surface turning and the guide surface turning are respectively performed, the maximum cutting amount is controlled within the range of 0-0.3mm, and the cutting amount of the last pass is controlled within the range of 0.08-0.15mm. In S4, the bearing surface turning and the guide surface turning are respectively performed by turning the guide surface in the forward direction and turning the bearing surface in the return direction.

[0028] Beneficial effects: the variable width is controlled by the program, so that the function of the cutting tooth is simplified, and the tool structure is greatly simplified, so that the shape of the cutting tooth of the tool is more regular and simple, and the cutting amount is more reasonable, the cutting amount redundancy is smaller than that of the prior art, material waste is reduced, and interference is avoided in the machining process due to the existence of the helix angle in the thread machining process and the lateral angle of the bearing surface and the guide surface. Both sides participate in cutting, one tool is used for multiple purposes, and the tool can meet the use requirements of various variable width wedge threads, and has high universality. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A structure diagram of the variable width thread cutting tool provided by the embodiment of the application is shown in the figure.

[0030] Figure 2 A structure diagram of the variable width thread cutting tool provided by the embodiment of the application is shown in the figure. Figure 1 A cross-sectional view of A-A is shown in the figure.

[0031] Figure 3 A structure diagram of the cutting tooth provided by the embodiment of the application is shown in the figure.

[0032] Figure 4 A structure diagram of the cutting tooth provided by the embodiment of the application is shown in the figure. Figure 3 A cross-sectional view of B-B is shown in the figure.

[0033] Figure 5 A cross-sectional view of C-C is shown in the figure. Figure 3 A cross-sectional view of C-C is shown in the figure.

[0034] Figure 6 A flowchart of the variable width thread cutting method provided by the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0035] The following will be further described in detail through specific embodiments:

[0036] The marks in the drawings of the specification include: tool body 1, tool body inscribed circle 2, fixed hole 3, chip breaker groove 4, rake face 5, arc 6, cutting tooth 7, left bottom plane 71, left bottom arc surface 72, guide surface 73, left top arc surface 74, tooth top plane 75, right top arc surface 76, bearing surface 77, right bottom arc surface 78, right bottom plane 79, tooth profile reference horizontal axis 8.

[0037] The embodiment is basically as shown in the accompanying drawings Figure 1 and Figure 2 : including tool body 1, the diameter of tool body inscribed circle 2 can be 15.875 mm, convenient to fix with the machine tool and size matching; the center of the tool body 1 is provided with a fixed hole 3, the fixed hole 3 has a taper, the inner hole diameter is controlled within 6.3-6.6 mm, and the taper is controlled within 59-61 degrees, so as to improve the stability and firmness when installing with the machine tool; the tool body has three installation base surfaces which are mutually 60 degrees, which are adapted to the tool position angle θ1, θ1 is 30 degrees, and the integrity of the tool shape is matched; the tool body also has three chip breaker grooves 4 with an included angle of 60 degrees, as shown in Figure 2 : the rake face 5 and the arc 6 jointly form the chip breaker groove 4, the width d1 of the chip breaker groove 4 is controlled within 3-5 mm, the angle of the rake face 5 is controlled within 8-15 degrees, and the size of the arc is controlled within 1-2 mm, so that the shape and volume of the whole chip breaker groove 4 can be adapted to the chip amount, and in the machining process, the blockage is avoided; each of the chip breaker grooves 4 has a cutting tooth 7 at the outer edge, the position distance d2 is controlled within 2-4 mm, the height d3 is controlled within 23-24.3 mm, the tool thickness d4 is controlled within 6-6.5 mm, the tool tip height d5 is smaller than the tool thickness d4, and the difference is controlled within 0.15-0.3 mm, so as to ensure the appropriate cutting strength of the cutting tooth, and the tool size, material use and workpiece hardness are matched.

[0038] : as shown in Figure 3As shown, the cutting teeth 7 are in order from left to right as left bottom plane 71, left bottom arc surface 72, guide surface 73, left top arc surface 74, tooth top plane 75, right top arc surface 76, bearing surface 77, right bottom arc surface 78 and right bottom plane 79. The length of the guide surface 73 is controlled within 0.8-1.5mm (the length of each embodiment represents the length of the line segment itself), the included angle with the tooth profile reference horizontal axis 8 is controlled within 85-80°, the vertical height d6 of the tooth height of the guide surface is controlled within 1.5-2mm, which is suitable for the size of the conventional variable thread width thread and improves the versatility; the length of the bearing surface 77 is controlled within 0.5-1.2mm, the included angle of the bearing surface 77 and the guide surface 73 with the tooth profile reference horizontal axis 8 is the same, the vertical height d7 of the tooth height of the bearing surface is controlled within 1.2-1.7mm, which is suitable for the size of the conventional variable thread width thread and improves the versatility, and d6 is greater than d7 in the selection of specific size, so as to form the taper of the thread. Figure 4 As shown, the lateral angle θ2 of the guide surface is controlled within 2-4 degrees. Figure 5 As shown, the lateral angle θ3 of the bearing surface is controlled within 2-4 degrees, and the lateral angles of the two can be the same or different, both of which are greater than the helix angle of the thread, greater than arcTan(P / πd), wherein P is the pitch and d is the thread diameter.

[0039] The tooth top plane 75 and the right bottom plane 79 are parallel to the tooth profile reference horizontal axis 8, which improves the rapidity and accuracy of positioning; the length of the tooth top plane 75 is controlled within 1-1.8mm, and the length of the right bottom plane 79 is controlled within 5.5-8mm; the left bottom plane 71 has a first included angle with the tooth profile reference horizontal axis 8, the first included angle is controlled within 5-12 degrees, and the length is controlled within 0.3-2.3mm, which is matched in size and has higher matching degree with the size of the conventional variable thread width thread.

[0040] The left bottom arc surface 72 has a radius controlled within 0.2-0.3mm, and the central angle thereof is the same as the included angle between the left bottom plane 71 and the guide surface 73; the left top arc surface 74 has a radius controlled within 0.2-0.3mm, and the central angle thereof is the same as the included angle between the tooth top plane 75 and the guide surface 73, which is matched with the size of the conventional variable thread width thread and is convenient for molding.

[0041] The right top arc surface 76 has a radius controlled within 0.2-0.3mm, and the central angle thereof is the same as the included angle between the tooth top plane 75 and the bearing surface 77; the right bottom arc surface 78 has a radius controlled within 0.2-0.3mm, and the central angle thereof is the same as the included angle between the right bottom plane 79 and the bearing surface 77.

[0042] The cutting tool with the above structure and data dimensions has a simple structure, reasonable size matching, and strong versatility in the relationship between dimensions. When designing other types of variable width thread cutting tools, the dimensions of each part can be determined more quickly, improving the machining and forming of the tool itself.

[0043] When the above-mentioned cutting tools are used for machining, if Figure 6 As shown, the method includes the following steps:

[0044] S1: An eccentric screw installed in the fixing hole of the cutting tool, with the screw hole deviating from the center hole of the tool by 0.2mm, connects to the turning tool holder of the CNC lathe and is then tightened by a pressure plate. When one of the cutting teeth is damaged, during the process of switching to another cutting tooth, since the tooth tip plane is horizontal and the overall structure is simple, it can be quickly repositioned with the fewest positioning surfaces. The horizontal alignment method provides accurate positioning, convenient installation, does not affect the processing progress, and maintains the continuity of processing.

[0045] S2: The rake face and the arc together form the chip breaker groove, which is used for chip removal when turning variable width wedge threads. The rake face is placed on the horizontal plane so that the rake face of the tool is on the center line of the workpiece, and the tolerance is controlled within ±0.15mm.

[0046] S3: Machine tool program settings control the thread width variation; therefore, it can simplify the function of cutting teeth and further greatly simplify the structural shape of cutting teeth;

[0047] S4: Perform bearing surface turning and guide surface turning separately, with multiple passes. The maximum depth of cut is controlled within the range of 0-0.3mm, and the depth of cut of the last pass is controlled within the range of 0.08-0.15mm. Specifically, the guide surface is turned during the forward pass, and the bearing surface is turned during the return pass. After turning on both sides, a variable width thread shape is formed, which is suitable for the turning requirements of variable width threads with different pitches and tapers.

[0048] The difficulty in machining variable-width threads lies in quickly and accurately locating the point of width variation. Existing technologies often require multiple tools working together for positioning, which is cumbersome and demands a high level of skill from the operator. This solution integrates and modularizes the machining of variable-width threads, providing a universally applicable tool that reduces the demands on the operator. It allows for rapid location and machining of the variable-width point within a suitable range.

[0049] Compared with the prior art, the variable tooth width thread cutting tool and cutting method provided by the present invention have the following advantages:

[0050] 1) the guiding surface and the bearing surface both have lateral angles, both sides can be cut, the thread torque resistance is increased, the cutting force is further reduced, the cutting amount is small, the efficiency is higher, the tool is not easy to cause vibration, the machining precision is improved; at the same time, due to the existence of the helix angle in the thread machining process, the bearing surface and the guiding surface both have lateral angles, the interference generated in the machining process is avoided, and the thread machining quality is improved.

[0051] 2) the included angle of the guiding surface and the bearing surface with the tooth profile reference horizontal axis is the same, so that when cutting both sides, the tool stress load is uniformly distributed, the tool service life is improved; at the same time, on this basis, combined with the structure design that the tooth top plane and the right bottom plane are both parallel to the tooth profile reference horizontal axis, the positioning of the thread during machining is fast and accurate, the installation is convenient, time and labor are saved.

[0052] 3) on the basis that the tooth top plane and the right bottom plane are both parallel to the tooth profile reference horizontal axis, the left bottom plane has a first included angle with the tooth profile reference horizontal axis, so that the thread feed does not interfere with the workpiece, and in cooperation with other structures, the tool connection strength and the over-torque performance can be significantly improved.

[0053] 4) on the basis of the above structure, the other parts of the cutting tooth are designed with different angles or lengths, the number of radian sections is reasonably set, the mutual relationship is high, the chip removal effect is increased, and the thread machining difficulty is reduced.

[0054] The above-mentioned is only an embodiment of the present application, and the specific structure and characteristics of the scheme are not described in detail, and the ordinary technical personnel in the art know all the ordinary technical knowledge in the technical field of the application before the application date or the priority date, can know all the prior art in the field, and has the ability to apply conventional experimental means before the date, the ordinary technical personnel in the art can improve and implement the scheme under the inspiration of the present application, some typical known structures or known methods should not be an obstacle for the ordinary technical personnel in the art to implement the present application. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should be considered as the protection scope of the present application, which will not affect the effect and practicality of the patent.

Claims

1. A variable width thread cutting tool comprising a tool body having a central bore, three mounting surfaces on the tool body, the mounting surfaces being 60 degrees apart, characterised in that, The tool body further has three chip breakers with an included angle of 60 degrees; each of the chip breakers has a cutting tooth on the outer edge; the cutting tooth has, from left to right, a left bottom plane, a left bottom arc surface, a guide surface, a left top arc surface, a tooth top plane, a right top arc surface, a bearing surface, a right bottom arc surface, and a right bottom plane; the guide surface and the bearing surface have the same included angle with a tooth profile reference horizontal axis; the tooth top plane and the right bottom plane are parallel to the tooth profile reference horizontal axis; the left bottom plane has a first included angle with the tooth profile reference horizontal axis; the guide surface and the bearing surface have a lateral angle greater than a thread helix rise angle; the central angle of the left bottom arc surface is the same as the included angle between the left bottom plane and the guide surface; the central angle of the left top arc surface is the same as the included angle between the tooth top plane and the guide surface; the central angle of the right top arc surface is the same as the included angle between the tooth top plane and the bearing surface; the central angle of the right bottom arc surface is the same as the included angle between the right bottom plane and the guide surface. The lateral angle depends on the size of the thread pitch and the thread diameter; the lateral angle is controlled within a range of 2-4 degrees; The vertical height of the guide surface tooth height is greater than the vertical height of the bearing surface tooth height; The length of the tooth top plane is controlled within a range of 1-1.8 mm; the length of the right bottom plane is controlled within a range of 5.5-8 mm; and the length of the left bottom plane is controlled within a range of 0.3-2.3 mm.

2. A variable-flank thread cutting tool according to claim 1, wherein, The included angle between the guide surface and the bearing surface and the tooth profile reference horizontal axis is controlled within a range of 85-80 degrees.

3. The variable-flank thread cutting tool according to claim 1, wherein, The first included angle is controlled within a range of 5-12 degrees.

4. The variable-flank thread cutting tool according to claim 1, wherein, The lateral angles of the guide surface and the bearing surface are the same.

5. The variable-flank thread cutting tool according to claim 1, wherein, The lateral angles of the guide surface and the bearing surface are different.

6. The variable-flank thread cutting tool according to claim 1, wherein, The nose height of the tool is less than the thickness of the tool, and the difference is controlled within a range of 0.15-3 mm.

7. A method of cutting variable-flank-width threads, characterized by, The method comprises the following steps: S1: The eccentric screw installed in the fixing hole of the cutting tool is connected with the turning tool rod of the numerical control lathe, and then the tool is pressed by the pressing plate, wherein the screw hole is deviated from the center hole of the tool by 0.2 mm; S2: The rake face and the arc together form a chip breaker, which is used for turning the variable width wedge thread and discharging chips, the rake face is placed on the horizontal plane, the tool rake face is on the center line of the workpiece, and the tolerance is controlled within a range of ±0.15 mm; S3: The program of the machine tool is set to control the change of the thread width; S4: The bearing surface turning and the guide surface turning are respectively performed, the maximum cutting amount is controlled within a range of 0-0.3 mm, and the cutting amount of the last cut is controlled within a range of 0.08-0.15 mm.

8. The method of cutting variable-flank thread cutters according to claim 7, wherein, In S4, the bearing surface turning and the guide surface turning are respectively performed by turning the guide surface in the forward direction and turning the bearing surface in the return direction.

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