Arc thread flank machining method and device

Abstract

The invention belongs to the technical field of thread machining, and particularly relates to an arc thread flank machining method and device. The method comprises the following steps: determining an equivalent tooth bottom width, an equivalent tooth crest width and an equivalent tooth height when a tooth form is equivalent to a trapezoid and an equivalent tool width when an arc turning tool is equivalent to a trapezoid turning tool based on a tool nose radius, an actual tooth height, a tooth bottom arc radius and a tooth form angle; setting a radial spacing, and determining the number of processing layers according to the equivalent tooth height; the tool nose positions of the adjacent layers of tools are controlled to be spaced by the radial distance in the radial feeding direction and spaced by the product of the radial distance and a half thread angle tangent value in the axial direction, and the offset coordinates of the tool noses of all the layers are calculated through the equivalent tooth bottom width, the equivalent tooth crest width and the thread angle; the axial direction is the direction of a lathe rotating shaft; layered machining is carried out according to the offset coordinates of each layer of tool nose, so that only one turning tool needs to be used when the tooth # imgabs0 # and the tooth side of the arc thread are machined, and the machining efficiency is improved while obvious tool marks are prevented from appearing on the tooth-shaped surface.

Description

Technical Field

[0001] The invention belongs to the technical field of thread processing, and in particular relates to a method and a device for processing arc thread flanks. Background Art

[0002] Threaded connection is a common connection method. Compared with ordinary metric threads, MJ threads, etc., arc threads have great advantages in processing and manufacturing, structural strength, and fatigue resistance. The Chinese utility model patent with authorization announcement number CN209818480U discloses a high-strength arc thread connection pair. The arc thread connection pair adopts an arc thread tooth profile. The internal thread and the external thread are in surface contact and the force is uniform. It can effectively reduce the stress concentration when the thread is loaded and has good fatigue resistance. The patent discloses two arc thread structures with major thread diameters of 42 and 48, and pitches of 6.35 and 8.5 respectively. The patent with authorization announcement number CN116877555B discloses a double-ended stud for connecting the root of wind turbine blades and a processing method thereof. The external thread of the threaded section of the double-ended stud is an arc thread, and the nominal diameter d of the arc thread is 42 and 48 respectively. 公称 =36mm~40mm, arc thread pitch Pr=(0.153~0.192)d 公称 , arc thread tooth height hr = (0.37 ~ 0.44) Pr, arc thread minor diameter d1r = d 公称 -0.8746Pr.

[0003] The tooth profile of the arc thread is a symmetrical structure, including two symmetrical tooth tops, tooth sides composed of edge lines and a tooth bottom. In traditional technology, trapezoidal turning tools are generally used to machine the tooth sides of arc threads, and arc turning tools are used to machine the arc teeth of arc threads. The tool needs to be changed during the processing. There may be errors in the tool alignment between the arc turning tool and the trapezoidal turning tool, resulting in obvious tool marks on the tooth profile surface. And when using the trapezoidal turning tool to process the tooth side, since the tooth profile angle accuracy of the tooth side depends on the clamping accuracy of the trapezoidal tool, in order to ensure the tooth side processing accuracy, it takes a long time to align the tool, resulting in low arc thread processing efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a method and device for processing the arc thread tooth side, so as to solve the problem that when using a trapezoidal turning tool to process the arc thread tooth side, the tool needs to be changed during the arc thread processing, which may cause obvious tool marks on the tooth surface and low processing efficiency.

[0005] In order to solve the above technical problems, the present invention provides a method for processing the tooth side of an arc thread, comprising: determining the equivalent tooth bottom width when the tooth profile is equivalent to a trapezoid according to the tool tip radius and the tooth profile angle, determining the equivalent tooth height when the tooth profile is equivalent to a trapezoid according to the actual tooth height, the tool tip radius, the tooth bottom arc radius and the tooth profile angle, determining the equivalent tooth top width when the tooth profile is equivalent to a trapezoid according to the equivalent tooth height, the equivalent tooth bottom width and the tooth profile angle, and using the equivalent tooth bottom width as the equivalent tool width when the tool is equivalent to a trapezoidal turning tool; the tool is an arc turning tool; the radial spacing is set, and the number of processing layers is determined according to the equivalent tooth height; the tool tip positions of adjacent layers are controlled to be spaced by the radial spacing in the radial feed direction and by the product of the radial spacing and the half tangent value of the tooth profile angle in the axial direction, and the tool tip offset coordinates of each layer are calculated using the equivalent tooth bottom width, the equivalent tooth top width and the tooth profile angle; the axial direction is the direction of the lathe rotation axis; and layered processing is performed according to the tool tip offset coordinates of each layer.

[0006] Furthermore, the method for calculating the offset coordinates of the tool tip of each layer is as follows: first, the Z-direction offset Z of the tool tip position of each layer relative to the origin O is calculated. n and the X-direction offset X of the tool tip relative to the origin O n , and then according to X n and Z n Determine the tool tip offset coordinates of each layer when machining the tooth side, X n and Z n The calculation formula is:

[0007] X n =-nΔX

[0008]

[0009] Where n is the nth layer of the processing layer; ΔX is the radial spacing, W′ 顶 is the equivalent crest width, W′ 底 is the equivalent tooth bottom width, θ is the tooth profile angle, the origin O is the intersection of the tooth top and the tooth profile symmetry axis, the radial retraction direction of the turning tool is the positive X direction, the radial feed direction of the turning tool is the negative X direction, the positive direction of the angular momentum when the spindle rotates counterclockwise is the positive Z direction, and the negative direction of the angular momentum when the spindle rotates counterclockwise is the negative Z direction.

[0010] Furthermore, according to the Z-direction offset Z of the tool tip position of each layer relative to the origin O n The maximum Z-direction offset distance ΔZ of the tool tip relative to the origin O max Determine the number of cutters per layer when machining the tooth side: If Z n <ΔZ max , then the number of knives per layer is 2, and the corresponding tool tip offset coordinate is (X n , Z n ) and (X n , -Zn ); otherwise, the number of knives per layer is 3, and the corresponding tool tip offset coordinate is (X n , Z n )、(X n ,0)、(X n , -Z n ).

[0011] Furthermore, the maximum Z-direction offset distance ΔZ of the tool tip relative to the origin O is max It is 0.5 times the equivalent tool width.

[0012] Furthermore, the equivalent tooth bottom width is calculated according to the following formula:

[0013]

[0014] Among them, W′ 底 is the equivalent tooth bottom width, R 刀 is the tool tip radius, and θ is the tooth angle.

[0015] Furthermore, the equivalent tooth height is calculated according to the following formula:

[0016]

[0017] Among them, H' is the equivalent tooth height, R 底 is the arc radius of the tooth bottom, and H is the actual tooth height.

[0018] Furthermore, the equivalent crest width is calculated according to the following formula:

[0019]

[0020] Among them, W′ 顶 is the equivalent crest width.

[0021] Furthermore, the radial spacing is selected according to the maximum feed amount in the radial feed direction:

[0022] ΔX≤ΔX max

[0023]

[0024] Where ΔX is the radial spacing, ΔX max is the maximum feed amount in the radial feed direction, R 刀 is the tool tip radius, R z is the surface roughness and θ is the tooth angle.

[0025] Furthermore, the tool tip radius must be greater than or equal to the minimum tip radius and less than or equal to the maximum tip radius, the maximum tip radius is equal to the tooth bottom arc radius, the minimum tip radius is equal to the set multiple of the maximum tip radius, and the set multiple is greater than or equal to 1 / 3 and less than or equal to 1 / 2.

[0026] The beneficial effects of the above technical solution are as follows: the present invention is a pioneering invention, which uses an arc turning tool to process the tooth side of the arc thread. Considering that the blade side of the arc turning tool is an arc surface, which is tangent to the tooth side edge line of the tooth profile to be processed, the present invention refers to the trapezoidal turning tool for profiling, calculates the equivalent parameters of the arc turning tool and the tooth profile to be processed, and sets the radial spacing. Based on the set radial spacing and the equivalent tooth height, the number of processing layers of the tooth side of the arc thread equivalent to the trapezoid is determined, and the tool is controlled to be spaced at intervals of the radial spacing in the radial feed direction and at intervals of the product of the radial spacing and the tangent value of half the tooth profile angle in the axial direction. Based on the above equivalent parameters, the offset coordinates of each layer are calculated, and the tooth side of the arc thread is layered according to the offset coordinates, so that the tooth side of the arc thread is processed. Only one turning tool is needed for machining the tooth side, and there is no need to change tools or align tools during machining. This solves the problem of obvious cutting marks on the tooth profile surface caused by the tool alignment error between the arc turning tool and the trapezoidal tool when machining the tooth side of the arc thread with a trapezoidal turning tool. At the same time, there is no need to spend a lot of time on the tool alignment accuracy of the trapezoidal turning tool, which improves the machining efficiency of the arc thread.

[0027] In order to solve the above technical problems, the present invention also provides a circular arc thread flank processing device, including a processor, wherein the processor is used to execute computer program instructions to implement the circular arc thread flank processing method introduced above.

[0028] The beneficial effects of the above technical solution are as follows: the present invention is a pioneering invention, which uses an arc turning tool to process the tooth side of the arc thread. Considering that the blade side of the arc turning tool is an arc surface, which is tangent to the tooth side edge line of the tooth profile to be processed, the present invention refers to the trapezoidal turning tool for profiling, calculates the equivalent parameters of the arc turning tool and the tooth profile to be processed, and sets the radial spacing. Based on the set radial spacing and the equivalent tooth height, the number of processing layers of the tooth side of the arc thread equivalent to the trapezoid is determined, and the tool is controlled to be spaced at intervals of the radial spacing in the radial feed direction and at intervals of the product of the radial spacing and the tangent value of half the tooth profile angle in the axial direction. Based on the above equivalent parameters, the offset coordinates of each layer are calculated, and the tooth side of the arc thread is layered according to the offset coordinates, so that the tooth side of the arc thread is processed. Only one turning tool is needed for machining the tooth side, and there is no need to change tools or align tools during machining. This solves the problem of obvious cutting marks on the tooth profile surface caused by the tool alignment error between the arc turning tool and the trapezoidal tool when machining the tooth side of the arc thread with a trapezoidal turning tool. At the same time, there is no need to spend a lot of time on the tool alignment accuracy of the trapezoidal turning tool, which improves the machining efficiency of the arc thread. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flowchart of arc thread flank processing according to an embodiment of the method of the present invention;

[0030] Figure 2 It is a schematic diagram of the tooth side machining by a trapezoidal turning tool in the prior art;

[0031] Figure 3 is a geometric relationship diagram when calculating equivalent parameters in an embodiment of the method of the present invention;

[0032] Figure 4 is a geometric relationship diagram for calculating ΔL in an embodiment of the method of the present invention;

[0033] Figure 5 is the calculation ΔX of the method embodiment of the present invention max The geometric relationship diagram of

[0034] Figure 6 This is a tool path diagram of the first layer with 3 knives in the method embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clear, the specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings.

[0036] The invention uses an arc turning tool to process the tooth side of the arc thread, and calculates the equivalent parameters of the arc turning tool and the tooth profile to be processed with reference to the trapezoidal turning tool, and calculates the tool tip offset coordinates of each layer when the tool moves according to the radial spacing and the equivalent parameters obtained by profiling, and controls the arc turning tool to process the tooth side of the arc thread layer by layer according to the offset coordinates of the tool tip of each layer, so that the tooth profile of the processed arc thread Only one turning tool is needed for machining the tooth side, and there is no need to change tools or align tools during machining. This solves the problem of obvious cutting marks on the tooth profile surface caused by the tool alignment error between the arc turning tool and the trapezoidal tool when machining the tooth side of the arc thread with a trapezoidal turning tool. At the same time, there is no need to spend a lot of time on the tool alignment accuracy of the trapezoidal turning tool, which improves the machining efficiency of the arc thread.

[0037] Method Embodiment

[0038] A method for processing arc thread flanks of the present invention, as Figure 1 As shown, the specific process is as follows:

[0039] 1. Profiling is performed based on the principle of machining tooth flanks with a trapezoidal turning tool. According to the actual parameters of the tooth profile and the tool tip radius R 刀 Calculate the equivalent parameters of the arc turning tool and the tooth profile to be processed. The actual parameters of the tooth profile include: tooth profile angle θ (in degrees), tooth bottom arc radius R 底 and the actual tooth height H. The equivalent parameter of the arc turning tool is the equivalent tool width W′刀 The equivalent parameters of the tooth profile to be processed include the equivalent tooth bottom width W′ 底 , equivalent tooth height H′ and equivalent tooth crest width W′ 顶 .

[0040] In traditional technology, a trapezoidal turning tool is generally used to process the tooth side, and the angle formed by the left and right sides of the tooth side is the tooth angle. Figure 2 As shown, the trapezoidal turning tool has three cutting edges, and the angle between the left and right cutting edges is equal to the tooth angle of the tooth profile to be processed, so that the tooth side can be conveniently processed while ensuring the roughness. In order to improve the processing efficiency and avoid obvious tool marks on the tooth profile surface, the present invention adopts the same tool as the one used to process the tooth bottom arc, that is, the arc turning tool to process the tooth side, and there is no need to change the tool during the arc thread processing. However, the left and right two-edge cutting processing method requires knowing the tool width, tooth bottom width, tooth height and tooth top width. Since the side of the blade of the arc turning tool is an arc surface, which is tangent to the tooth side edge line of the tooth profile to be processed, the traditional processing method cannot be used directly. Therefore, the present invention performs profiling processing on the tooth side based on a trapezoidal turning tool, determines the equivalent tooth bottom width when the tooth profile is equivalent to a trapezoid according to the tool tip radius and the tooth profile angle, determines the equivalent tooth height when the tooth profile is equivalent to a trapezoid according to the actual tooth height, the tool tip radius, the tooth bottom arc radius and the tooth profile angle, determines the equivalent tooth top width when the tooth profile is equivalent to a trapezoid according to the equivalent tooth height, the equivalent tooth bottom width and the tooth profile angle, and uses the equivalent tooth bottom width as the equivalent tool width when the tool is equivalent to a trapezoidal turning tool.

[0041] Specifically, Figure 3 As shown, the intersection of the tooth top and the tooth profile symmetry axis is taken as the origin O, the radial retraction direction of the turning tool is the positive direction of X, the radial feed direction of the turning tool is the negative direction of X, the positive direction of the angular momentum when the spindle rotates counterclockwise is the positive direction of Z, and the negative direction of the angular momentum when the spindle rotates counterclockwise is the negative direction of Z. The spindle refers to the rotating spindle of the lathe. Figure 3 The geometric relationship shown can be obtained:

[0042]

[0043] Among them, the tool tip radius is greater than or equal to the minimum tool tip radius and less than or equal to the maximum tool tip radius, and the maximum tool tip radius is equal to R 底 , the minimum tool tip radius is equal to the maximum tool tip radius of the set multiple, the set multiple is greater than or equal to 1 / 3 and less than or equal to 1 / 2. In order to improve the processing efficiency, preferably, the set multiple is set to 1 / 2. At this time, the selection range of the tool tip radius is:

[0044] 0.5R 底 ≤R 刀 ≤R 底

[0045] Select the appropriate tool nose radius from this range for machining.

[0046] 2. Determine the radial spacing ΔX in the radial feed direction.

[0047] ΔX in the radial feed direction must be less than or equal to the maximum feed amount ΔX in the radial feed direction max , the present invention is based on ΔX max Select the appropriate feed spacing ΔX, ΔX refers to the absolute distance between the current layer tool tip position and the previous layer tool tip position in the radial feed direction. ΔX max The calculation method is as follows:

[0048] To ensure the surface roughness R z , first calculate the feed amount ΔL along the tooth side direction, such as Figure 4 The geometric relationship shown, O 刀 is the center of the tool tip arc of the current layer, O′ 刀 is the center of the tool tip arc of the next adjacent layer. The calculation process is as follows:

[0049] R z =R 刀 -AB

[0050]

[0051]

[0052] Taking into account the tooth angle, according to Figure 5 It can be seen that ΔX max The calculation formula is:

[0053]

[0054] ΔX≤ΔX max

[0055] According to the above formula, the appropriate feed spacing ΔX in the radial feed direction is selected, and the number of processing layers N is determined according to the equivalent tooth height, N=H′ / ΔX.

[0056] 3. Control the tool tip positions of adjacent layers in the radial feed direction with the radial spacing as the interval, and in the axial direction with the product of the radial spacing and half the tangent value of the tooth profile angle as the interval, and use the equivalent tooth bottom width, equivalent tooth top width and tooth profile angle to calculate the tool tip offset coordinates of each layer; the axial direction is the direction of the lathe rotation axis, and the tool tip position decreases in the radial feed direction and the axial direction according to the corresponding intervals.

[0057] The method for calculating the offset coordinates of the tool tip of each layer is as follows: first, calculate the Z-direction offset Z of the tool tip position of each layer relative to the origin O. n and the X-direction offset X of the tool tip relative to the origin O n , the calculation formula is:

[0058] X n =-nΔX

[0059]

[0060] Wherein, n is the nth layer of the processing layer.

[0061] Then, according to the Z-direction offset of the tool tip relative to the origin O and the maximum Z-direction offset distance ΔZ of the tool tip relative to the origin O max Determine the number of cutting tools for each layer: Usually Z n <ΔZ max , at this time, the number of knives for each layer is 2, and the corresponding tool tip offset coordinate is (X n , Z n )、(X n , -Z n ); if Z n ≥ΔZ max , then the number of tooling per layer increases by one, that is, the number of tooling per layer is 3, and the corresponding tool tip offset coordinate is (X n , Z n )、(X n ,0)、(X n , -Z n ).

[0062] Among them, ΔZ max =0.5W' 刀 .

[0063] 4. The tooth side of the arc thread is processed according to the calculated tool tip offset coordinates of each layer when the tool moves.

[0064] According to the tool tip offset coordinates of each layer, layered processing is performed in a left-right feeding mode. Taking the feeding from right to left as an example, the Z-direction offset Z1 of the tool tip position of the first layer relative to the origin O and the X-direction offset X1 of the tool tip position of the first layer relative to the origin O are calculated. If Z1≥ΔZ max , then the tool tip offset coordinates of the first layer are (X1, z1), (X1, 0) and (X1, -Z1), and the tool path is as follows: Figure 6 As shown: First, the first cut is processed with (X1, Z1) as the offset coordinate, then the second cut is processed with (X1, 0) as the offset coordinate, and finally the last cut is processed with (X1, -Z1) as the offset coordinate. At this point, the first layer is processed. max , the tool tip offset coordinates of the first layer are (X1, Z1) and (X1, -Z1): first use (X1, Z1) as the offset coordinates to process the first cut, and finally use (X1, -Z1) as the offset coordinates to process the last cut. At this point, the first layer is processed.

[0065] Then, ΔX is used as the X-axis step, and the offset coordinates of the second layer are calculated in the above manner. The second layer is processed according to the offset coordinates of the second layer, and so on, until the Nth layer is processed, and the arc thread tooth side processing is completed.

[0066] Device Embodiment

[0067] The invention discloses a circular arc thread flank processing device, which is used to execute computer program instructions to implement the circular arc thread flank processing method described in the above method embodiment. The device can be a CNC lathe for processing threads, and the CNC lathe executes computer program instructions to control a circular arc turning tool to process the circular arc thread flank.

Claims

1. A method for processing arc thread flanks, characterized in that: include: Determine the equivalent tooth bottom width when the tooth profile is equivalent to a trapezoid according to the tool tip radius and tooth profile angle, determine the equivalent tooth height when the tooth profile is equivalent to a trapezoid according to the actual tooth height, tool tip radius, tooth bottom arc radius and tooth profile angle, determine the equivalent tooth top width when the tooth profile is equivalent to a trapezoid according to the equivalent tooth height, equivalent tooth bottom width and tooth profile angle, and use the equivalent tooth bottom width as the equivalent tool width when the tool is equivalent to a trapezoidal turning tool; the tool is an arc turning tool; Set radial spacing and determine the number of processing layers based on equivalent tooth height; The tool tip positions of adjacent layers are controlled to be spaced by radial spacing in the radial feed direction and by the product of radial spacing and half of the tangent value of tooth profile angle in the axial direction, and the tool tip offset coordinates of each layer are calculated using the equivalent tooth bottom width, equivalent tooth top width and tooth profile angle; the axial direction is the direction of the lathe rotation axis; Layered processing is performed according to the tool tip offset coordinates of each layer.

2. The arc thread flank processing method according to claim 1, characterized in that: The method for calculating the offset coordinates of the tool tip of each layer is as follows: First, calculate the Z-direction offset Z of the tool tip position of each layer relative to the origin O. n and the X-direction offset X of the tool tip relative to the origin O n , and then according to X n and Z n Determine the tool tip offset coordinates of each layer when machining the tooth side, X n and Z n The calculation formula is: X n =-nΔX Where n is the nth layer of the processing layer; ΔX is the radial spacing, W′ 顶 is the equivalent crest width, W′ 底 is the equivalent tooth bottom width, θ is the tooth profile angle, the origin O is the intersection of the tooth top and the tooth profile symmetry axis, the radial retraction direction of the turning tool is the positive X direction, the radial feed direction of the turning tool is the negative X direction, the positive direction of the angular momentum when the spindle rotates counterclockwise is the positive Z direction, and the negative direction of the angular momentum when the spindle rotates counterclockwise is the negative Z direction.

3. The arc thread flank processing method according to claim 2, characterized in that: According to the Z-direction offset Z of the tool tip position of each layer relative to the origin O n The maximum Z-direction offset distance ΔZ of the tool tip relative to the origin O max Determine the number of cutters per layer when machining the tooth side: If Z n <ΔZ max , then the number of knives per layer is 2, and the corresponding tool tip offset coordinate is (X n , Z n ) and (X n , -Z n ); otherwise, the number of knives per layer is 3, and the corresponding tool tip offset coordinate is (X n , Z n )、(X n ,0)、(X n , -Z n ).

4. The arc thread flank processing method according to claim 3, characterized in that: The maximum offset distance ΔZ of the tool tip relative to the origin O in the Z direction max It is 0.5 times the equivalent tool width.

5. The arc thread flank processing method according to claim 1, characterized in that: Calculate the equivalent tooth bottom width according to the following formula: Among them, W′ 底 is the equivalent tooth bottom width, R 刀 is the tool tip radius, and θ is the tooth angle.

6. The arc thread flank processing method according to claim 5, characterized in that: Calculate the equivalent tooth height according to the following formula: Among them, H' is the equivalent tooth height, R 底 is the arc radius of the tooth bottom, and H is the actual tooth height.

7. The arc thread flank processing method according to claim 6, characterized in that: Calculate the equivalent crest width according to the following formula: Among them, W′ 顶 is the equivalent crest width.

8. The arc thread flank processing method according to claim 1, characterized in that: The radial spacing is selected according to the maximum feed amount in the radial feed direction: ΔX≤ΔX max Where ΔX is the radial spacing, ΔX max is the maximum feed amount in the radial feed direction, R 刀 is the tool tip radius, R z is the surface roughness and θ is the tooth angle.

9. The arc thread flank processing method according to claim 1, characterized in that: The tool tip radius must be greater than or equal to the minimum tool tip radius and less than or equal to the maximum tool tip radius, the maximum tool tip radius is equal to the tooth bottom arc radius, the minimum tool tip radius is equal to the set multiple of the maximum tool tip radius, and the set multiple is greater than or equal to 1 / 3 and less than or equal to 1 / 2.

10. A circular arc thread flank processing device, comprising a processor, characterized in that: The processor is used to execute computer program instructions to implement the arc thread flank processing method as described in any one of claims 1-9.

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