An inner arc tooth type curved rake surface gear cutting tool and a construction method thereof

Abstract

This invention relates to the field of gear removing tools, specifically to a removable gear with a curved rake face and its construction method for internal circular arc gears. The removable gear with a curved rake face includes a tool body and a plurality of teeth evenly arranged circumferentially along the tool body. Each tooth includes a flank face, a rake face, and a cutting edge, with the flank face adjacent to the rake face. The cutting edge is the conjugate line of the tooth surface of the internal circular arc gear to be machined, and the cutting edge is the intersection line between the tooth surface of the internal circular arc gear to be machined and the rake face. The flank face is a free-form surface composed of a plurality of cutting edges. The rake face is a free-form surface that controls the constant rake angle of the cutting edge. This invention ensures a consistent rake angle for the removable gear with a curved rake face, achieving high machining accuracy, guaranteeing good surface quality, and maintaining constant precision.

Description

Technical Field

[0001] This invention relates to the field of tooth cutting tools, specifically to a tooth cutting tool with an internal circular arc tooth curved rake face and its construction method. Background Technology

[0002] Gears are fundamental components used in numerous industries. Currently, the domestic gear industry faces significant structural contradictions: there is a huge production capacity for low-end gears, but insufficient production capacity for high-end gears. The quality stability and reliability of high-end gear products still lag far behind those of developed countries, and a large number of high-end gear products rely on imports, including involute and cycloidal gears, and even more so circular arc gears.

[0003] Scudding (also known as power skiving) is a new gear machining technology that was truly realized in the 21st century, boasting advantages such as high efficiency, high precision, and dry cutting. However, despite years of development, scudding technology has not yet been widely adopted, largely due to the lack of significant breakthroughs in tool design. Because existing internal circular arc tooth scudding cutters struggle to ensure a consistent cutting rake angle, affecting machining accuracy, most currently available internal circular arc tooth scudding cutters are merely models and have not yet been effectively and universally implemented in actual production. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an internal circular arc tooth rake face cutting cutter and its construction method, which improves the consistency of the cutting rake angle of the cutting edge and enhances the machining accuracy of internal circular arc gears.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: On the one hand, an internal circular arc tooth type curved rake face scraper is provided, including a cutter body and a plurality of cutter teeth evenly arranged along the circumference of the cutter body; The cutting teeth include a flank face, a rake face, and a cutting edge, with the flank face adjacent to the rake face. The cutting edge is the conjugate line of the tooth surface of the internal circular arc gear to be machined, and the cutting edge is the intersection line between the tooth surface of the internal circular arc gear to be machined and the rake face. The flank face is a free-form surface composed of several cutting edges; The rake face is a freeform surface that controls the rake angle of the cutting edge to be constant.

[0006] Furthermore, the cutting teeth are either straight or helical.

[0007] Furthermore, the cutting rake angle of the cutting edge is 5-10°.

[0008] On the other hand, a method for constructing a cutting tool with an internal circular arc tooth-type curved rake face is provided, including the following steps: Obtain the internal circular arc gear to be machined, and let the tooth surface of the internal circular arc gear that contacts the cutting edge be the P tooth surface; Based on the conjugate principle, a conjugate tooth surface model of P tooth surface is established. Several points are selected on the conjugate tooth surface of P tooth surface according to the constraint conditions as cutting edge point values. The cutting edge point values ​​are fitted with spline curves to obtain a spatial curve, which is the cutting edge. Then, construct the flank and rake faces based on the cutting edge. Furthermore, the constraint condition for the cutting edge profile value points is to construct several tangent circular arc segments on the conjugate surface of the P tooth surface, and then discretize the circular arc segments according to a fixed central angle to obtain the cutting edge profile value points.

[0009] Furthermore, by changing the displacement coefficient of the conjugate tooth surface of P tooth surface, several conjugate tooth surfaces of P tooth surface are obtained, and several cutting edges are obtained. The cutting edges are fitted with a curved surface, and the resulting curved surface is the flank face.

[0010] Furthermore, let the type value point on the corresponding cutting edge be... ,in And establish a tool cutting angle reference plane including the base plane, the cutting plane and the orthogonal plane; Select a line segment located on the intersection of the orthogonal plane and the base plane. ,and The direction points inward towards the inside of the cutting teeth, passing through the shape value point in the orthogonal plane. Construct line segments ,make The direction points inward towards the inside of the blade teeth, making the line segment With line segment The included angle between them is equal to the set cutting rake angle of the cutting edge; Line segment Perform surface fitting, where The obtained surface is called a surface. ; Will and Connect them with line segments, Constructed as a filled surface ,in ; curved surface and curved surfaces Together they form the rake face.

[0011] Furthermore, the constructed internal circular arc tooth-type curved rake face cutting tool is ground using a CNC grinding machine, characterized by the following steps: Based on the constructed three-dimensional model of the internal circular arc tooth-type curved rake face scraper, the machining parameters are set, the tool position data is generated through the UG NX machining module, and the tool position data is converted into a CNC machining program; based on the CNC machining program, the scraper blank is divided into regions to obtain several areas to be processed; Based on the CNC machining program, tool position data, grinding wheel geometric parameters and blank geometric model, the theoretical initial contact time and theoretical contact separation time between the CNC grinding wheel and each area to be machined are calculated, and the theoretical contact duration is also calculated. A first vibration monitoring unit is installed at the spindle end of the CNC grinding machine, with its detection end in contact with the support end of the grinding wheel spindle; a second vibration monitoring unit is installed at the clamping support end of the tooth cutter blank; the first and second vibration monitoring units are used to collect vibration signals; Based on the vibration signals collected by the first vibration monitoring unit and the second vibration monitoring unit, the actual initial contact time point and the actual contact separation time point of each area to be processed are identified, and the actual contact duration is calculated. The theoretical initial contact time point is compared with the actual initial contact time point, the theoretical contact separation time point with the actual contact separation time point, and the theoretical contact duration with the actual contact duration for each area to be processed. If the difference exceeds the preset operating deviation value, it is determined that the processing accuracy of the area to be processed does not meet the requirements.

[0012] Furthermore, during the processing of each processing area, the vibration fluctuations monitored by the first vibration monitoring unit and the second vibration monitoring unit are obtained: when the vibration fluctuations occur synchronously, the vibration fluctuations of the two monitoring units are obtained. If they exceed their respective thresholds, the grinding processing position at that time point is marked as abnormal; when the vibration fluctuations occur asynchronously, the grinding processing position at that time point is directly marked as abnormal.

[0013] Furthermore, each processing area is divided according to the position of the cutting teeth, ensuring that each processing area contains at least one cutting tooth.

[0014] The above approach has the following beneficial effects: The internal circular arc tooth type curved rake face cutting cutter of the present invention has equal cutting rake angles at all points on the cutting edge; during the machining of circular arc gears, it can ensure the quality of the machined surface of the circular arc gear and has high machining accuracy. Moreover, when the internal circular arc tooth type curved rake face cutting cutter is used to cut circular arc gears, the cutting force fluctuation is small, and it has high machining stability.

[0015] In addition, by setting vibration monitoring points at the clamping ends of the grinding wheel spindle and the workpiece, the vibration between the two can be monitored. When the two are grinding normally, the actual contact and separation time points and contact duration of each area should be close to the theoretical initial contact time point, theoretical contact separation time point and theoretical contact duration estimated based on the CNC machining program. The vibration of the two can reflect the contact situation, thereby judging the machining accuracy of each area of ​​the cutting tool during the grinding process and ensuring that the final cutting tool meets the structural requirements.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the internal circular arc tooth type curved rake face scraper structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the tooth structure of the internal arc tooth type curved rake face scraper according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the cutting edge structure of an internal circular arc tooth type curved rake face scraper according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the formation of the back face of an internal circular arc tooth-type rake face scraper according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the cutting angle reference plane of the internal circular arc tooth type curved rake face scraper according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the formation of the rake face of an internal circular arc tooth-type rake face cutting tool according to an embodiment of the present invention.

[0018] The reference numerals in the accompanying drawings include: 1. Tool body; 2. Tool teeth; 3. Rake face; 4. Front face; 5. Cutting edge. Detailed Implementation

[0019] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The following detailed description illustrates the specific implementation method: Example 1, such as Figure 1The image shows a rebar cutter for internal circular arc gears, comprising a cutter body and a plurality of cutting teeth evenly arranged along the circumference of the cutter body. The number of cutting teeth matches the number of teeth of the internal circular arc gear to be machined, ensuring high efficiency and accuracy during rebar machining. For example, when the number of teeth of the internal circular arc gear to be machined is large, the number of cutting teeth should also be increased. Furthermore, the cutting teeth can be spur teeth or helical teeth to adapt to different types of internal circular arc gear rebar machining.

[0021] like Figure 2 As shown, the cutting tooth includes a flank face, a rake face, and a cutting edge, with the flank face adjacent to the rake face. Since gear cutting aims to produce perfectly conjugate tooth surfaces to ensure contact and motion characteristics during gear meshing, this embodiment designs the cutting edge based on the conjugate principle. This ensures that the cutting edge of the gear cutter is the conjugate line of the internal circular arc gear tooth surface to be machined, and that the cutting edge is the intersection line between the internal circular arc gear tooth surface and the rake face. Furthermore, the rake angle of the cutting edge is 5-10°.

[0022] The flank face is a free-form surface composed of several cutting edges, while the rake face is a free-form surface that controls the rake angle of the cutting edges to be constant.

[0023] The construction method of the above-mentioned internal circular arc tooth type curved rake face cutting cutter is as follows: like Figure 3 As shown, the internal circular arc gear to be machined is obtained. Let the tooth surface of the internal circular arc gear in contact with the cutting edge be the P tooth surface. According to the conjugate principle, the conjugate tooth surface model of the P tooth surface is established. On the conjugate tooth surface of the P tooth surface, several points are selected as cutting edge shape points according to the constraint conditions. The cutting edge shape points are fitted with spline curves to obtain a spatial curve, which is the cutting edge.

[0024] The constraint condition for the cutting edge type value point is to construct several tangent circular arc segments on the conjugate surface of the P tooth surface, and then discretize the circular arc segments according to a fixed central angle to obtain the cutting edge type value point.

[0025] After the cutting edge is constructed, the flank face and rake face are constructed based on the cutting edge: like Figure 4 As shown, by changing the displacement coefficient of the conjugate tooth surfaces of tooth surface P, several conjugate tooth surfaces of tooth surface P are obtained, and several cutting edges are obtained. The cutting edges are then fitted with a surface, and the resulting surface is the flank face. The displacement coefficient describes the offset distance between the centerline of the cutting tool and the pitch circle of the gear during machining of modified gears. When the tool moves outward, the displacement coefficient is positive; when it moves inward, the displacement coefficient is negative; the displacement coefficient of a standard gear is 0.

[0026] like Figure 5 and Figure 6 As shown, let the shape value point on the corresponding cutting edge be... ,in And establish a tool cutting angle reference plane including the base plane, the cutting plane and the orthogonal plane.

[0027] Select a line segment located on the intersection of the orthogonal plane and the base plane. ,and The direction points inward towards the inside of the cutting teeth, passing through the shape value point in the orthogonal plane. Construct line segments ,make The direction points inward towards the inside of the blade teeth, making the line segment With line segment The included angle between them is equal to the set cutting rake angle of the cutting edge.

[0028] Line segment Perform surface fitting, where The obtained surface is called a surface. .Will and Connect them with line segments, Constructed as a filled surface ,in Curved surface and curved surfaces Together they form the rake face.

[0029] Example 2 This embodiment uses a CNC grinding machine to grind the constructed internal circular arc tooth type curved rake face cutting cutter. Preferably, a Walter five-axis grinding machine is used for grinding the constructed internal circular arc tooth type curved rake face cutting cutter. In order to judge the machining accuracy of the cutting cutter during the actual grinding process and ensure that the cutting cutter meets the construction accuracy, this embodiment monitors the machining status of the cutting cutter during the machining process in the following way.

[0030] First, machining parameters are set based on the constructed internal circular arc tooth-type curved rake face cutting tool. Toolpath data is generated through the machining module of UG NX and then converted into a CNC machining program. Machining parameters include, but are not limited to, grinding wheel speed, feed rate, depth of cut, feed step, cooling method, grinding wheel type, grinding wheel radius, grinding wheel width, grinding wheel fillet parameters, and the transformation relationship between the machine coordinate system and the workpiece coordinate system. The toolpath data can be in CLSF format, APT format, or other CAM intermediate formats, and the CNC machining program can be a G-code program.

[0031] The blank of a rake face scraper with internal circular arc teeth is divided into regions based on a CNC machining program to obtain several regions to be machined. Preferably, each region to be machined is divided according to the position of the cutting teeth, ensuring that each region contains at least one cutting tooth, thereby ensuring the accuracy monitoring of the subsequent machining of each cutting tooth. Specifically, the scraper can be divided into cutting tooth region 1, cutting tooth region 2, ... nth cutting tooth region according to the cutting tooth number; each region to be machined may include at least a part of the rake face, tooth groove, tooth tip, or tooth flank of a cutting tooth. For complex cutting teeth, a cutting tooth can be further divided into multiple sub-regions, each sub-region corresponding to a CNC machining program segment.

[0032] Then, based on the CNC machining program, the initial contact time and the end separation time between the grinding wheel of the CNC grinding machine and each area to be machined are calculated and defined as the theoretical initial contact time and theoretical contact separation time of each area to be machined. Based on the theoretical initial contact time and theoretical contact separation time of each area to be machined, the contact duration between the grinding wheel of the CNC grinding machine and each area to be machined is calculated and defined as the theoretical contact duration of each area to be machined.

[0033] Specifically, the theoretical initial contact time and theoretical contact separation time can be calculated by analyzing the motion segments in the CNC machining program. For example, the starting coordinates, ending coordinates, tool axis vector, feed rate, and acceleration / deceleration parameters of each G-code segment can be extracted. Combined with the grinding wheel radius, grinding wheel width, grinding wheel fillet, and the blank CAD model, the time of the first intersection and the final separation between the grinding wheel envelope and the solid area to be machined can be determined through geometric intersection, discrete voxel method, or Boolean operations. For five-axis grinding machines, the tool position data can be post-processed and converted into motion quantities for each servo axis using the machine tool kinematic model, and then the time points can be calculated based on the feed rate of each axis. The theoretical contact duration is equal to the theoretical contact separation time minus the theoretical initial contact time.

[0034] Because there is contact between the grinding wheel and the workpiece during the grinding process of a gear cutter, vibrations are inevitably generated during this contact and throughout the machining of a certain area. Therefore, based on these vibrations, it is possible to determine whether the two are in contact, the duration of contact, and the fluctuations during contact. Since the vibrations are usually small and may not be directly observable visually, this embodiment uses a vibration monitoring unit to independently collect data on their vibrations. The vibration monitoring unit used in this embodiment is a vibration sensor, preferably a piezoelectric accelerometer, MEMS accelerometer, or capacitive accelerometer. The sensor sensitivity, range, and frequency response range can be selected according to the grinding conditions; for example, a sensitivity of 10mV / g to 1000mV / g, a range of ±10g to ±100g, and a frequency response range of 0.5Hz to 20kHz. The data acquisition card sampling frequency is preferably not less than 20kHz, more preferably 50kHz to 100kHz, and uses a 16-bit or higher A / D converter.

[0035] A first vibration monitoring unit is installed at the spindle end of the grinding wheel on a CNC grinding machine, with its detection end in contact with the spindle support end of the grinding wheel. Specifically, the first vibration monitoring unit can be fixed to the grinding wheel spindle housing, spindle bearing seat, or spindle support end via magnetic mounting, threaded connection, or adhesive bonding. The detection direction can be at least one of the radial, tangential, or axial directions of the grinding wheel. A second vibration monitoring unit is installed at the blank clamping support end of the internal arc-tooth rake face cutter. Specifically, it can be installed on the workpiece fixture, indexing shaft, tailstock, or clamping support. The detection direction can be at least one of the radial, tangential, or axial directions of the workpiece. The first and second vibration monitoring units are synchronously acquired through the same data acquisition card, the same hardware trigger signal, or the same clock synchronization protocol to ensure consistent time reference.

[0036] Based on the vibration signals collected by the first vibration monitoring unit and the second vibration monitoring unit, the actual initial contact time and actual contact separation time of each processing area are obtained, and the actual contact duration of each processing area is calculated based on the actual initial contact time and actual contact separation time of each processing area.

[0037] Specifically, after the grinding process begins, vibration signals are first collected when the machine tool is idling or when the grinding wheel is not in contact with the workpiece as baseline signals. These baseline signals are then detrended, bandpass filtered, and statistically processed to obtain the baseline root mean square value, baseline peak-to-peak value, and noise standard deviation. When grinding a specific area to be processed, the vibration signals collected by the first and second vibration monitoring units are processed using a sliding window method. At least one characteristic quantity is calculated for each window, including the root mean square value, peak-to-peak value, envelope amplitude, or wavelet packet energy. When the characteristic quantity exceeds the contact threshold for N consecutive sampling points, it is determined that the grinding wheel and the workpiece have come into contact. The time point when the contact condition is first met in both the first and second vibration monitoring units and the time difference between them is within the synchronization window is recorded as the actual initial contact time point. When the characteristic quantity is below the separation threshold for M consecutive sampling points, it is determined that the grinding wheel and the workpiece have separated. The time point after the last contact condition is met in both the first and second vibration monitoring units, when both are below the separation threshold and remain below it for M consecutive sampling points, is recorded as the actual contact-separation time point. The actual contact duration is equal to the actual contact separation time minus the actual initial contact time.

[0038] For example, when grinding the first tooth of a tooth-grinding cutter, at 15 seconds after the CNC grinding machine starts running according to the CNC machining program, both the first vibration monitoring unit and the second vibration monitoring unit collect vibration signals exceeding the contact threshold. Therefore, the actual initial contact time is 15 seconds. During the CNC grinding machine's operation according to the CNC machining program, the vibration signals generated by both units are continuously detected. At 45 seconds, the first vibration monitoring unit and the second vibration monitoring unit collect vibration signals below the separation threshold and continue for a set time. Therefore, the actual contact separation time is 45 seconds, and the actual contact duration is 30 seconds.

[0039] Based on the above, the processing accuracy of each area to be processed is obtained by sequentially comparing the theoretical initial contact time with the actual initial contact time, the theoretical contact separation time with the actual contact separation time, and the theoretical contact duration with the actual contact duration. Specifically, the theoretical initial contact time with the actual initial contact time, the theoretical contact separation time with the actual contact separation time, and the theoretical contact duration with the actual contact duration of each area to be processed should be similar. Considering mechanical inertia, servo response, and acceleration / deceleration processes, a running deviation value is usually set, i.e., the allowable difference between the theoretical and actual values. For example, if the running deviation value is set to 0.5s, then the difference between the theoretical initial contact time with the actual initial contact time, the theoretical contact separation time with the actual contact separation time, and the theoretical contact duration with the actual contact duration of each area to be processed should be within 0.5s. If the difference of any comparison item exceeds 0.5s, the grinding accuracy of that area is judged to be low. The operating deviation value can be set fixedly or dynamically adjusted according to the feed rate, acceleration, servo bandwidth, and grinding wheel linear speed. For example, it can be set to 0.1s to 1.0s, preferably 0.3s to 0.8s. The judgment result can be divided into three levels: qualified, warning, and unqualified: a difference less than or equal to the operating deviation value is qualified; a difference greater than the operating deviation value but less than twice the operating deviation value is a warning; and a difference greater than twice the operating deviation value is unqualified.

[0040] To more specifically monitor abnormalities during the grinding process of the tooth cutter, vibration fluctuations monitored by the first and second vibration monitoring units were acquired during the processing of each processing area, and the following judgments were made: When the vibration fluctuations monitored by the first vibration monitoring unit and the second vibration monitoring unit occur synchronously, the amount of vibration fluctuations monitored by the first vibration monitoring unit and the second vibration monitoring unit is acquired. When the amount of vibration fluctuations monitored by the first vibration monitoring unit and the second vibration monitoring unit exceeds their respective thresholds, an abnormality is marked at that time point in the grinding process. When the vibration fluctuations monitored by the first vibration monitoring unit and the second vibration monitoring unit occur asynchronously, an abnormality is directly marked at that time point in the grinding process.

[0041] Synchronous vibration fluctuation refers to the time difference between the detection of vibration fluctuation characteristics by the first vibration monitoring unit and the second vibration monitoring unit being less than or equal to the synchronization window. The synchronization window can be set according to the sampling frequency and grinding conditions, for example, from 1ms to 10ms, preferably from 2ms to 5ms. Asynchronous vibration fluctuation refers to the time difference between the two being greater than the synchronization window. The vibration fluctuation quantity can be at least one of the following: root mean square increment, peak-to-peak increment, envelope amplitude, wavelet packet energy, band energy, or kurtosis. The threshold values ​​for the first and second vibration monitoring units can be set separately, preferably 2 to 5 times the baseline root mean square value, or the baseline mean plus 3 to 5 times the standard deviation.

[0042] The principle behind the above judgment is as follows: When both the grinding wheel and the workpiece vibrate simultaneously, it may be due to factors such as the structure or material of the surface being machined, thus requiring further assessment of the vibration fluctuations. When the vibration fluctuation exceeds a preset threshold, it may be due to excessive vibration caused by other factors, potentially leading to a decrease in the machining accuracy of the cutting teeth or grooves at that location. For vibration fluctuations occurring unilaterally, it may be due to abnormal vibration generated by either the grinding wheel or the workpiece, which is highly likely to result in a decrease in the machining accuracy of the cutting teeth or grooves at that location.

[0043] Furthermore, when it is determined that vibration fluctuations occur asynchronously, they can be classified according to their source: if only the first vibration monitoring unit experiences abnormal fluctuations, the abnormality may originate from grinding wheel imbalance, spindle bearing malfunction, poor grinding wheel dressing, or loose grinding wheel installation; if only the second vibration monitoring unit experiences abnormal fluctuations, the abnormality may originate from workpiece fixture looseness, indexing mechanism malfunction, insufficient tailstock support rigidity, or stress release during blank clamping; if both are synchronous and exceed the threshold, the abnormality may originate from sudden load changes in the grinding zone, material hard spots, insufficient cutting fluid, grinding burns, or chatter. The above classification results can be stored together with the processing area number, cutting tooth number, time point, characteristic quantity, threshold, and alarm level.

[0044] Furthermore, when it is determined that the machining accuracy of a certain area to be processed is low or there is an abnormality, closed-loop control can be implemented: the controller issues an alarm signal, a processing pause signal, or a feed rate reduction signal; or it compensates for the deviation between the actual contact time and the theoretical contact time in the subsequent CNC machining program of the cutting teeth; or it adjusts the grinding wheel speed, feed rate, grinding depth, and cooling parameters; or it prompts the operator to perform grinding wheel dressing, tool resetting, fixture inspection, or blank reloading. Through the above closed-loop method, the machining accuracy and consistency of subsequent cutting teeth can be improved.

[0045] In summary, this embodiment monitors the machining accuracy of each machining area and any abnormalities during the grinding process of the tooth cutter to ensure that the final ground tooth cutter meets the structural requirements.

[0046] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A type of internal circular arc tooth curved rake face scraper, characterized in that, It includes a blade body and a number of blade teeth evenly arranged along the circumference of the blade body; The cutting teeth include a flank face, a rake face, and a cutting edge, with the flank face adjacent to the rake face. The cutting edge is the conjugate line of the tooth surface of the internal circular arc gear to be machined, and the cutting edge is the intersection line between the tooth surface of the internal circular arc gear to be machined and the rake face. The flank face is a free-form surface composed of several cutting edges; The rake face is a freeform surface that controls the rake angle of the cutting edge to be constant.

2. The internal circular arc tooth type curved rake face scraper according to claim 1, characterized in that, The cutting teeth are either straight or helical.

3. The internal circular arc tooth type curved rake face scraper according to claim 2, characterized in that, The cutting rake angle of the cutting edge is 5-10°.

4. A method for constructing an internally circular arc toothed curved rake face cutter, used to construct the internally circular arc toothed curved rake face cutter as described in any one of claims 1-3, characterized in that, Includes the following steps: Obtain the internal circular arc gear to be machined, and let the tooth surface of the internal circular arc gear that contacts the cutting edge be the P tooth surface; Based on the conjugate principle, a conjugate tooth surface model of P tooth surface is established. Several points are selected on the conjugate tooth surface of P tooth surface according to the constraint conditions as cutting edge point values. The cutting edge point values ​​are fitted with spline curves to obtain a spatial curve, which is the cutting edge. Then, construct the flank face and rake face based on the cutting edge.

5. The method for constructing an internal circular arc tooth type curved rake face cutting cutter according to claim 4, characterized in that, The constraint condition for the cutting edge type value point is to construct several tangent circular arc segments on the conjugate surface of the P tooth surface, and then discretize the circular arc segments according to a fixed central angle to obtain the cutting edge type value point.

6. The method for constructing an internal circular arc tooth type curved rake face cutting cutter according to claim 4, characterized in that, By changing the displacement coefficient of the conjugate tooth surface of P tooth surface, several conjugate tooth surfaces of P tooth surface are obtained, and several cutting edges are obtained. The cutting edges are fitted with a curved surface, and the resulting curved surface is the flank face.

7. The method for constructing an internal circular arc tooth type curved rake face cutting cutter according to claim 6, characterized in that, Let the type value point on the corresponding cutting edge be... ,in And establish a tool cutting angle reference plane including the base plane, the cutting plane and the orthogonal plane; Select a line segment located on the intersection of the orthogonal plane and the base plane. ,and The direction points inward towards the inside of the cutting teeth, passing through the shape value point in the orthogonal plane. Construct line segments ,make The direction points inward towards the inside of the blade teeth, making the line segment With line segment The included angle between them is equal to the set cutting rake angle of the cutting edge; Line segment Perform surface fitting, where The obtained surface is called a surface. ; Will and Connect them with line segments, Constructed as a filled surface ,in ; curved surface and curved surfaces Together they form the rake face.

8. The method for constructing an internal circular arc tooth type curved rake face cutting cutter according to claims 1-6, wherein the constructed internal circular arc tooth type curved rake face cutting cutter is ground by a CNC grinding machine, characterized in that, Includes the following steps: Based on the constructed three-dimensional model of the internal circular arc tooth-type curved rake face scraper, the machining parameters are set, the tool position data is generated through the UG NX machining module, and the tool position data is converted into a CNC machining program; based on the CNC machining program, the scraper blank is divided into regions to obtain several areas to be processed; Based on the CNC machining program, tool position data, grinding wheel geometric parameters and blank geometric model, the theoretical initial contact time and theoretical contact separation time between the CNC grinding wheel and each area to be machined are calculated, and the theoretical contact duration is also calculated. A first vibration monitoring unit is installed at the spindle end of the CNC grinding machine, with its detection end in contact with the support end of the grinding wheel spindle; a second vibration monitoring unit is installed at the clamping support end of the tooth cutter blank; the first and second vibration monitoring units are used to collect vibration signals; Based on the vibration signals collected by the first vibration monitoring unit and the second vibration monitoring unit, the actual initial contact time point and the actual contact separation time point of each area to be processed are identified, and the actual contact duration is calculated. The theoretical initial contact time point is compared with the actual initial contact time point, the theoretical contact separation time point with the actual contact separation time point, and the theoretical contact duration with the actual contact duration for each area to be processed. If the difference exceeds the preset operating deviation value, it is determined that the processing accuracy of the area to be processed does not meet the requirements.

9. The method for constructing an internal circular arc tooth type curved rake face cutting cutter according to claim 8, characterized in that, During the processing of each processing area, the vibration fluctuations monitored by the first vibration monitoring unit and the second vibration monitoring unit are obtained: when the vibration fluctuations occur synchronously, the vibration fluctuations of the two monitoring units are obtained. If they exceed their respective thresholds, the grinding processing position at that time point is marked as abnormal; when the vibration fluctuations occur asynchronously, the grinding processing position at that time point is directly marked as abnormal.

10. The method for constructing an internal circular arc tooth type curved rake face cutting cutter according to claim 8, characterized in that, Each processing area is divided according to the position of the cutting teeth, ensuring that each processing area contains at least one cutting tooth.

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