Measurement method and measurement device for gear characteristic quantity

Abstract

The invention provides a method and a device for measuring a gear characteristic quantity. The measuring method comprises the following steps that a gear tooth profile (GP) is obtained, the gear tooth profile (GP) comprises an average curve (1), an actual measurement curve (2) and a marking line (3), the average curve (1) is discontinuous, the actual measurement curve (2) is continuous, and the marking line (3) is parallel to the transverse axis of the gear tooth profile (GP) and intersects with the actual measurement curve (2); obtaining a prediction curve (4) based on the average curve (1) from the gear tooth profile (GP), the prediction curve (4) being a continuous curve; and obtaining the gear characteristic quantity based on the prediction curve (4) and the actual measurement curve (2).

Description

Technical Field

[0001] The present invention relates to the field of gear detection, and more particularly, to a method and an apparatus for measuring gear characteristic quantities. Background Art

[0002] This section aims to provide background information related to understanding the various technologies described herein. As implied by the title of this section, this is in no way intended to imply that the related technologies are necessarily prior art. Therefore, it should be understood that any statement in this section should be read from this perspective and not as an admission of prior art.

[0003] For strict gear measurement accuracy and increasingly complex transmission components, the best measurement technology, optimized application software, and machines are essential. To ensure that the intermediate shaft gears meet the quality requirements, advanced testing instruments (such as Klingelnberg gear testing instruments) are used to conduct tooth profile and helix angle tests on the intermediate shaft gears. The helix angle is the direction of the tooth profile of the gear, which refers to the direction of the inclined plane and the normal of the gear teeth on the gear. The helix angle is an important factor affecting the gear transmission motion and the axial force. There are two types of helix angles for gears: the positive helix angle and the negative helix angle. The positive helix angle means that the direction of the teeth on the gear is the same as the direction of the force transmitted by the gear, and the negative helix angle means that the direction of the teeth on the gear is opposite to the direction of the force transmitted by the gear. Different helix angle types will affect aspects such as the efficiency, noise, and lifespan of gear transmission. The exemplary Klingelnberg gear testing instrument is a precision measurement benchmark in the industry, which can test intermediate shaft gears and automatically generate a standard PDF (Portable Document Format) test report to ensure the integrity and accuracy of the test. However, the quantitative indicators given in the test report are limited, and it is difficult to customize measurement indicators for specific requirements. In actual processes, engineers also pay attention to other quantities, such as the tooth profile root offset, the S-shaped performance of the tooth profile, and obvious protrusions on the tooth surface. These problems will directly cause NVH (Noise, Vibration, Harshmness) problems in gear mother components such as bearings. This requires a large amount of manual time to read the helix angle trend curve to determine whether bearings of different batches are qualified. This method strongly relies on manual experience and there are situations where multiple judgment results are inconsistent. In addition, the judgment of whether the report is qualified also requires a large amount of time from our company to assist, and the judgment result of whether it is qualified may also cause disputes with suppliers, consuming manpower.

[0004] In addition, due to the limitations of the Klingelnberg equipment version and usage rights (requiring payment), gear suppliers cannot guarantee the provision of color reports, and most are still in black and white. Therefore, it is urgent to solve the problem of decoupling the measured curve (solid line) and the average curve (dashed line) of the black and white report. Summary of the Invention

[0005] The object of the present invention is to provide a method for measuring gear characteristics, which can make more complete use of gear tooth profile diagrams, and has high accuracy, high efficiency and low cost.

[0006] In addition, the present invention also aims to solve or alleviate other technical problems existing in the prior art.

[0007] The present invention solves the above problems by providing a method and a device for measuring gear characteristic quantities. Specifically, according to one aspect of the present invention, there is provided:

[0008] A method for measuring gear characteristic quantities, wherein the measuring method comprises the following steps:

[0009] Obtain a gear tooth profile diagram, which includes an average curve, a measured curve and a marking line. Among them, the average curve is discontinuous, the measured curve is continuous, and the marking line is parallel to the horizontal axis of the gear tooth profile diagram and intersects the measured curve;

[0010] Obtain a prediction curve based on the average curve from the gear tooth profile diagram, and the prediction curve is a continuous curve;

[0011] Obtain the gear characteristic quantity based on the prediction curve and the measured curve.

[0012] Optionally, according to an embodiment of the present invention, the marking line includes a first marking line and a second marking line that are parallel to each other. The obtaining of the prediction curve includes:

[0013] Based on the coordinate positions of the average curve segments located outside the first marking line, obtain an initial prediction curve;

[0014] Set an intercepting line, which is parallel to the first marking line and has a distance from the first marking line in the direction inside the first marking line;

[0015] Based on the number and positions of the intersections of the intercepting line with the average curve and the measured curve, update the initial prediction curve until the intercepting line overlaps with the second marking line, and the update ends;

[0016] Based on the updated initial prediction curve, fit the prediction curve, and the prediction curve spans the first marking line and the second marking line.

[0017] Optionally, according to an embodiment of the present invention, based on the number and positions of the intersection points of the intercepting line with the average curve and the measured curve, updating the initial prediction curve includes:

[0018] In response to the number of intersection points of the intercepting line with the average curve and the measured curve being 1, calculate whether the absolute value of the deviation between the predicted coordinate value and the actual coordinate of this intersection point is less than the coordinate deviation threshold. If so, update the initial prediction curve in combination with the coordinate position of this intersection point. If not, regard this intersection point as a null value and update the initial prediction curve accordingly;

[0019] In response to the number of intersection points of the intercepting line with the average curve and the measured curve being 2, calculate the absolute values of the deviations between the predicted coordinate values and the actual coordinates of these two points respectively, and select the intersection point corresponding to the smaller absolute value to update the initial prediction curve.

[0020] Wherein, the predicted coordinate value is obtained based on the initial prediction curve before updating.

[0021] Optionally, according to an embodiment of the present invention, obtaining the prediction curve includes: removing the background grid of the gear tooth profile diagram; obtaining a single set of tooth profile curves; and filtering the background noise of the single set of tooth profile curves.

[0022] Optionally, according to an embodiment of the present invention, the gear characteristic quantity is the tooth profile root offset degree. Obtaining the gear characteristic quantity based on the prediction curve and the measured curve includes:

[0023] Obtain the involute base circle diameter, involute extension evaluation starting circle diameter, involute pitch circle diameter of the gear tooth profile diagram, and the coordinate position corresponding to the involute pitch circle diameter;

[0024] Calculate the curvature radii corresponding to the involute extension evaluation starting circle diameter and the involute pitch circle diameter respectively;

[0025] Calculate the coordinate position corresponding to the involute extension evaluation starting circle diameter;

[0026] Calculate the spacing between the prediction curve and the measured curve at the involute extension evaluation starting circle diameter as the tooth profile root offset degree.

[0027] Optionally, according to an embodiment of the present invention, obtaining the gear characteristic quantity based on the prediction curve and the measured curve includes:

[0028] Obtain a deviation curve based on the deviation between the prediction curve and the measured curve;

[0029] Calculate curve characteristic quantities based on the deviation curve as the gear characteristic quantities, where the curve characteristic quantities include one or more of the following characteristics:

[0030] The maximum positive offset distance, the maximum negative offset distance, the curve coverage area, the curve variance.

[0031] Optionally, according to an embodiment of the present invention, to obtain the gear characteristic quantities based on the predicted curve and the measured curve, further include:

[0032] Smooth the deviation curve;

[0033] Set up a clipping frame and a reference line, where the clipping frame is used to clip the deviation curve, and the reference line is a line parallel to the horizontal axis;

[0034] Judge whether the part of the deviation curve clipped by the clipping frame exists both above and below the reference line. If so, it is considered that the deviation curve is an S-shaped curve, and the gear tooth profile is considered to be S-shaped, as the gear characteristic quantity.

[0035] Optionally, according to an embodiment of the present invention, the gear tooth profile diagram is generated from the detection report of a Klingelnberg detection device.

[0036] According to another aspect of the present invention, there is provided a device for measuring gear characteristic quantities, where the measuring device is used to execute any one of the above measuring methods, and the measuring device includes:

[0037] An input module, configured to obtain a gear tooth profile diagram, where the gear tooth profile diagram includes an average curve, a measured curve, and a marking line. Among them, the average curve is discontinuous, the measured curve is continuous, and the marking line is parallel to the horizontal axis of the gear tooth profile diagram and intersects with the measured curve;

[0038] An extraction module, configured to obtain a predicted curve based on the average curve from the gear tooth profile diagram, where the predicted curve is a continuous curve;

[0039] A calculation module, configured to obtain the gear characteristic quantities based on the predicted curve and the measured curve.

[0040] According to still another aspect of the present invention, there is provided a computer-readable storage medium, on which a computer program is stored. Among them, when the computer program is executed by a processor, it implements any one of the above measuring methods.

[0041] According to another aspect of the present invention, there is provided a computer device, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor. Wherein, when the processor executes the computer program, any of the above-mentioned measurement methods is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] With reference to the accompanying drawings, the above and other features of the present invention will become apparent, wherein,

[0043] Figure 1 FIG. shows a schematic flow chart of a measurement method according to the present invention;

[0044] Figure 2 FIG. shows a gear tooth profile diagram according to the present invention;

[0045] Figure 3 FIG. shows a gear tooth profile diagram after removing the background grid according to the present invention;

[0046] Figure 4 FIG. shows a marking diagram of a single set of tooth profile curve regions according to the present invention;

[0047] Figure 5 FIG. shows a single set of tooth profile curve regions according to the present invention;

[0048] Figure 6 FIG. shows another single set of tooth profile curve regions according to the present invention;

[0049] Figure 7 FIG. shows a single set of tooth profile curves after removing background noise according to the present invention;

[0050] Figure 8 FIG. shows a schematic diagram of the formation of an initial prediction curve at the start stage according to the present invention;

[0051] Figure 9 FIG. shows a schematic diagram of an initial prediction curve formed up to the second marking line according to the present invention;

[0052] Figure 10 FIG. shows a schematic diagram of a predicted curve after fitting according to the present invention;

[0053] Figure 11 FIG. shows a schematic diagram of the measurement of the tooth profile root offset according to the present invention;

[0054] Figure 12 FIG. shows a schematic diagram of a deviation curve according to the present invention;

[0055] Figure 13 FIG. shows a schematic diagram of a smoothed deviation curve according to the present invention;

[0056] Figure 14 shows a design schematic diagram of a clipping frame relative to a deviation curve according to the present invention;

[0057] Figure 15 shows a design schematic diagram of a reference line relative to a deviation curve according to the present invention; and

[0058] Figure 16 shows a module schematic diagram of a measuring device according to the present invention. Detailed implementation manners

[0059] It is easy to understand that according to the technical solution of the present invention, without changing the essence of the present invention, those of ordinary skill in the art can propose various interchangeable structural ways and implementation manners. Therefore, the following detailed implementation manners and the accompanying drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction on the technical solution of the present invention.

[0060] The orientation terms such as up, down, left, right, front, back, front side, back side, top, bottom, etc. mentioned or possibly mentioned in this specification are defined relative to the structures shown in the respective drawings, and they are relative concepts. Therefore, they may change accordingly according to their different positions and different usage states. Therefore, these or other orientation terms should not be construed as restrictive terms. In addition, the terms "first", "second", "third", etc. or similar expressions are only used for descriptive and distinguishing purposes, and cannot be understood as indicating or implying the relative importance of the corresponding components.

[0061] Reference Figure 1 and Figure 2 , shows a flow schematic diagram of a measuring method according to the present invention and a gear tooth profile diagram according to the present invention.

[0062] The measuring method is used for gear characteristic quantities, wherein the measuring method includes the following steps:

[0063] S1: Obtain a gear tooth profile diagram GP, where the gear tooth profile diagram GP includes an average curve 1, a measured curve 2, and a marking line 3. Among them, the average curve 1 is discontinuous, the measured curve 2 is continuous, and the marking line 3 is parallel to the horizontal axis of the gear tooth profile diagram GP and intersects the measured curve 2;

[0064] S2: Obtain a prediction curve 4 based on the average curve 1 from the gear tooth profile diagram GP, and the prediction curve 4 is a continuous curve;

[0065] S3: Obtain the gear characteristic quantity based on the prediction curve 4 and the measured curve 2.

[0066] It should be noted that the naming methods of various method steps in this article are only for the convenience of distinction and reference, and do not necessarily represent the difference in the sequence of these method steps (unless clearly stated). They can be adjusted according to the actual situation, or even executed simultaneously.

[0067] It should be understood that the meanings expressed by the measured curve and the average curve / trace of the tooth profile diagram are as follows: Measured curve: The measured curve of the tooth profile diagram is the actual shape and size of the gear tooth profile obtained through actual measurement, or the actual helix trace measured on a certain cylinder of the tooth profile, which can be understood as an actual tooth direction line. Average curve: Through the measured curve, the tooth direction curve fitted by the least squares method is used as the average curve, which can also be understood as a tooth direction center line. In the design and manufacturing process, the average curve is used to evaluate the accuracy grade of the gear to ensure that the tooth profile of the gear meets the design requirements; the measured trace can reflect the influence of factors such as the actual manufacturing error and heat treatment deformation of the gear on the tooth profile. By analyzing the measured trace and the average curve, the manufacturing quality of the gear can be evaluated, and corresponding adjustments and optimizations can be made.

[0068] In the tooth profile diagram, there are also marked lines. There are significant differences in the distances between the average curve parts and the measured curve parts on both sides of the marked lines. The number of marked lines is usually two or three, but other numbers are not excluded. In addition, the marked lines are usually divided into two types: one above and one below. The trace part above the upper marked line is shorter, and the lower part is longer. The curve part above the lower marked line is longer, and the lower part is shorter. In this example, there are a total of three marked lines. The marked lines are parallel to the horizontal axis and intersect the measured curve horizontally. Depending on the discontinuous situation of the average curve, the marked lines can pass through or intersect the average curve.

[0069] According to the above technical solution, the extraction of the average curve and the measured curve is achieved through the construction of the prediction curve. Moreover, the prediction curve is a continuous curve, which can be conveniently extended and expanded as needed, and can supplement the missing part of the average curve as required. Thanks to the construction of this prediction trace and the comparison with the measured curve, various gear characteristic quantities can be obtained as needed for viewing. It should also be understood that these method steps can be automatically executed, and by comparing and analyzing the obtained gear characteristic quantities with the corresponding thresholds, it is further possible to determine whether the gear is abnormal. If there is an abnormality, an abnormality report can be generated. Further, for the report of tooth profile abnormality, this method or the corresponding system can achieve automatic prompt and reveal the basis and cause of the abnormality. All these information can be uploaded to the cloud, and the factory side can obtain the supplier test results in real time. Engineers at both the factory and the R & D side can view them, realizing automated, convenient, timely, and multi-dimensional tooth profile feature determination, abnormality detection, and prompt, and can achieve the purpose of this disclosure. Here, the gears are not particularly limited in this article and can be intermediate shaft gears or various gears for other usage scenarios.

[0070] In this article, the gear tooth profile diagram GP generated from the detection report of the Klingelnberg detection device is used as an example for illustration. However, it should be known that any tooth profile diagram with the required characteristics of the tooth profile diagram (such as the average curve, the measured curve, the marking line) and the corresponding coordinate data can be applied in accordance with the technical concepts and spirits of the various technical solutions of this disclosure and obtain the expected technical effects.

[0071] Combined with Figures 3 to 7 , respectively shown are a gear tooth profile diagram after removing the background grid according to an aspect of the present invention; a marked diagram of a single set of tooth profile curve regions according to an aspect of the present invention; a single set of tooth profile curve regions according to an aspect of the present invention; another single set of tooth profile curve regions according to an aspect of the present invention; and a single set of tooth profile curves after removing background noise according to an aspect of the present invention.

[0072] Optionally, the obtaining of the prediction curve 4 includes: S21: removing the background grid of the gear tooth profile diagram GP; S22: obtaining a single set of tooth profile curves; and S23: filtering the background noise of the single set of tooth profile curves.

[0073] Whether to perform these operations depends on the original image quality of the visible gear tooth profile diagram. Exemplarily, in step S21, the background grid is presented as a dot array, and the dots in some rows and columns are denser, while the dots in some rows and columns are sparser, presenting as a square grid form as a whole. Removing the background grid formed by these dots helps to better extract the average curve and improve the measurement quality. The distribution position of the background grid can be identified and removed through a self-positioning algorithm. For example, in the tooth profile diagram, first define a square box with a length and width of 24 * 24 pixels. Search for the coordinate positions of the grid points in this box, and use this point as the starting point. Then, the starting point overlaps with the grid points, and horizontal and vertical lines are extended based on this starting point, so as to cover or capture more grid points. Eventually, the coordinates of the global background grid points can be obtained. In a similar way, the dense points are also captured, and finally the deletion operation is completed.

[0074] In step S22, exemplarily, the interception of a single set of tooth profile curves is achieved by defining a box. Each set of tooth profile curves includes several marking lines, an average curve, and a measured curve. However, during the defining process, there may be some background noises, such as Figure 5 arrow symbols, and even in some relatively special cases, the bending degree of each set of tooth profile curves is relatively large. Therefore, during the box selection process, a part of multiple sets of tooth profile curves may be boxed out (for example Figure 6 ), and these background noises are not expected and also need to be removed or filtered.

[0075] Similarly exemplarily, the removal method is to take points horizontally from the topmost row of the box selection area (i.e., the first row). In Figure 5 the case where a point on the curve is intercepted, taking this point as the starting point, horizontally spread a certain number of pixels (for example, 30 pixels) to the left and right as the reserved part, and so on, to define the reserved area of the entire curve, and then delete the remaining area. The specific spreading amplitude can be flexibly adjusted according to experience or the actual interception effect, with the aim of being able to intercept a single set of tooth profile curves. In Figure 6 the case where two points are intercepted, at this time, it can be judged based on experience or other methods which point to use as the basis for subsequent corresponding steps of reservation. For example, when intercepting the left half of the tooth profile diagram, it is inclined to reserve the curve where the right-side intercepted point is located, while when intercepting the right half of the tooth profile diagram, it is inclined to reserve the curve where the left-side intercepted point is located. Eventually, adjustments or corrections can be made according to the actual results. Thus, the removal of background noises is completed. Therefore, in some tooth profile diagrams where tooth profile intersections are relatively serious (such as Figure 6 the case), it is inevitable that other tooth profiles will be intercepted during the cutting of a single tooth profile. This filtering method can very well retain the main curves in the figure and remove the interfering curves.

[0076] Combined with Figures 8 to 10, respectively showing a schematic diagram of the formation of an initial prediction curve according to the present invention at the beginning stage; a schematic diagram of an initial prediction curve according to the present invention when it is formed to the second marking line; and a schematic diagram of a predicted curve after fitting according to the present invention.

[0077] For clarity, these three figures are presented by rotating counterclockwise by 90 degrees based on the gear tooth profile diagram, which does not affect the concept and implementation of the present disclosure solution.

[0078] The marking line 3 includes a first marking line 31 and a second marking line 32 that are parallel to each other. The obtaining of the prediction curve 4 includes:

[0079] S24: Based on the coordinate positions of the average curve segments located outside the first marking line 31, obtain the initial prediction curve 41;

[0080] S25: Set up an intercept line 5, the intercept line 5 is parallel to the first marking line 31 and has a distance from the first marking line 31 in the direction inside the first marking line 31;

[0081] S26: Based on the number and positions of the intersection points of the intercept line 5 with the average curve 1 and the measured curve 2, update the initial prediction curve 41 until the intercept line 5 overlaps with the second marking line 32, and the update ends;

[0082] S27: Based on the updated initial prediction curve 41, fit the prediction curve 4, and the prediction curve 4 spans the first marking line 31 and the second marking line 32.

[0083] It should be noted that if there are more marking lines in the figure, such as a third marking line 33, it should be clear that data acquisition is based on the outermost or side-by-side first marking line. As slightly mentioned before, the lengths of the curve parts corresponding to the left and right sides of the marking line are significantly different. In this article, the shorter side is called the short side, and the longer side is called the long side. Taking Figure 8 as an example, the left side of the first marking line is the short side or the outside, and the right side is the long side or the inside; the right side of the second marking line is the short side or the outside, and the left side is the long side or the inside. According to prior knowledge or the characteristics of the tooth profile diagram, it can be known that in the outer direction of the first marking line, there are obvious differences and distances between the average curve and the measured curve, and the average curve is located below the measured curve. Therefore, the two can be distinguished, and the required dotted line (average curve) part can be selected, and the initial prediction curve can be fitted by extracting data (coordinate positions) from this part, as Figure 8 presented.

[0084] At Figure 8An intercept line is also drawn in the figure. The intercept line is vertically placed and gradually moves to the right starting from the position of the first marking line. During the movement, it will intersect with the measured curve, and depending on the shape of the average curve of the dashed line, it may also intersect with the average curve. It is possible to determine whether the intersection point belongs to the average curve or the measured curve based on this intersection situation, the number of intersection points, and the position of the intersection points, and update the initial prediction curve (i.e., refit) according to the judgment result. Thus, as the intercept line gradually moves to the right, the initial prediction curve is updated step by step until it reaches the position of the second marking line. At this time, it corresponds to Figure 9 the state.

[0085] Finally, according to Figure 10 It can be seen that based on the data of the initial prediction curve that has reached the second marking line, it is possible to sufficiently fit and predict the part outside the second marking line, thus completing the acquisition of the entire prediction curve and the extraction operation of the average curve. The prediction curve can be used as the basis for subsequent processes such as tooth profile analysis and anomaly reporting.

[0086] In some embodiments of the present disclosure, based on the number and position of the intersection points of the intercept line 5 with the average curve 1 and the measured curve 2, updating the initial prediction curve 41 includes:

[0087] S261: In response to the intercept line 5 having 1 intersection point with the average curve 1 and the measured curve 2, calculate whether the absolute value of the deviation between the predicted coordinate value and the actual coordinate of this intersection point is less than the coordinate deviation threshold. If so, update the initial prediction curve 41 in combination with the coordinate position of this intersection point. If not, regard this intersection point as a null value and update the initial prediction curve 41 based on this;

[0088] S262: In response to the intercept line 5 having 2 intersection points with the average curve 1 and the measured curve 2, calculate the absolute values of the deviations between the predicted coordinate values and the actual coordinates of these two points respectively, and select the intersection point corresponding to the smaller absolute value to update the initial prediction curve 41,

[0089] wherein, the predicted coordinate value is obtained based on the initial prediction curve 41 before the update.

[0090] It should be noted that in the case of step S261, when the intercept line has 1 intersection point with the average curve and the measured curve, there are two possibilities in this situation. One is that this point is a point on the measured curve, and at this time the corresponding position of the average curve is empty. The other is that this point is the overlapping point of the measured curve and the average curve (dashed line). In the former case, it is necessary to select a null value to update the initial prediction curve; in the latter case, directly select the coordinate data of this point to update the initial prediction curve.

[0091] For this purpose, this solution determines whether it is the former or the latter case by setting a threshold. That is, based on the initial prediction curve, the coordinate positions of the points in the column where the intercept line is located are predicted and compared with the coordinate positions of the intersection points. If the two are relatively close (or in other words, from the perspective of Figure 8 , the absolute value of the difference in the vertical axis values is relatively small), it is considered that this intersection point actually belongs to the points of the average curve and can be used to update the initial prediction curve. If the difference between the two is relatively large, it is considered that this intersection point is actually a point of the measured curve, and the average curve is empty at this column coordinate. Therefore, the initial prediction curve is updated with a null value.

[0092] In the case of step S262, there are 2 intersection points between the intercept line and the average curve and the measured curve, indicating that at this time, the column where the intercept line is located intersects with the points of both the measured curve and the average curve simultaneously. Therefore, it is necessary to determine which point is the one that needs to be used for updating, that is, to determine which point is the point of the average curve. Here, the absolute value is obtained in a similar manner as described above, and the intersection point corresponding to the absolute value with the smaller value is used as the point of the average curve, and the update operation is performed based on this. The reliability of this method is relatively high because the initial prediction curve is originally used to extract the average curve, and the initial prediction curve has obtained sufficient data of the real average curve (such as the data outside the first marking line) to form before, and the average curve is generally relatively regular. Therefore, the points predicted by the initial prediction curve should be relatively close to or have a small difference from the actual intersection points of the average curve. Hence, using this as a judgment criterion is reliable.

[0093] Combined with Figure 11 , it shows a schematic diagram for measuring the tooth profile root offset according to the present invention.

[0094] The gear characteristic quantity is the tooth profile root offset. Obtaining the gear characteristic quantity based on the prediction curve 4 and the measured curve 2 includes:

[0095] S31: Obtain the involute base circle diameter, involute extension evaluation starting circle diameter, involute pitch circle diameter of the gear tooth profile diagram GP, and the coordinate position corresponding to the involute pitch circle diameter;

[0096] S32: Calculate the curvature radii corresponding to the involute extension evaluation starting circle diameter and the involute pitch circle diameter respectively;

[0097] S33: Calculate the coordinate position corresponding to the involute extension evaluation starting circle diameter;

[0098] S34: Calculate the distance between the prediction curve 4 and the measured curve 2 at the involute extension evaluation starting circle diameter as the tooth profile root offset.

[0099] It can be seen that this technical solution gives an example of measuring the offset degree of tooth profile and tooth root using a prediction curve. It should be understood that the offset degree of tooth profile and tooth root refers to the deviation degree of the tooth root of the gear on the pitch circle. The size of the offset degree of tooth profile and tooth root will affect the load-bearing capacity and service life of the gear, so it needs to be controlled and adjusted.

[0100] In this embodiment, combined with Figure 2 the data shown, the involute base circle diameter is 56.53 microns (corresponding to d Figure 11 in S ), and the starting circle diameter of involute extension evaluation is 56.98 - 0.1 = 56.88 microns (corresponding to d Figure 11 in Ff ). Among them, 56.98 microns corresponds to d Figure 11 in Nf , that is, the tooth root position, which can also be understood as corresponding to the position of the second marking line. Usually, the evaluation of the tooth root offset degree is to estimate the offset at 0.1 micron of the tooth root. Therefore, the starting circle diameter of this evaluation is 0.1 micron less than 56.98, and this difference can be adjusted according to actual requirements. The involute pitch circle diameters include data such as 56.98, 61.73, 63.41, 64.70 microns, etc. Some or all of these data can be selected as needed for subsequent calculations.

[0101] It should be noted that the ordinate in the gear tooth profile diagram is related to involute data, and its values are not in equal proportion. It is necessary to convert the radius of curvature, and the difference or interval of the corresponding radius of curvature is in proportion, and the pixel interval of the coordinate position is also correspondingly in proportion. Then, combined with the coordinate position data in the figure, according to the previously obtained proportional relationship, the coordinate pixel interval and coordinate position between the tooth root at 0.1 micron and the tooth root position can be obtained. Finally, according to this coordinate position or interval, combined with the previously obtained prediction curve and measured curve data, the coordinate position interval between these two curves at 0.1 micron of the tooth root can be obtained, and this interval is the offset degree of tooth profile and tooth root.

[0102] Specifically, the calculation method of the involute pitch circle radius of curvature is formula one as follows:

[0103]

[0104] Among them, R represents the radius of curvature, r k represents half of the diameter of the circle corresponding to the required radius of curvature, and r b represents half of the involute base circle diameter. Combining the various diameter data mentioned above, the following Table 1 can be made:

[0105]

[0106] Table 1: List of involute circle diameters, radii of curvature, coordinate positions, and corresponding intervals

[0107] The coordinate positions in Table 1 refer to the pixel coordinate positions in the entire inspection report. Therefore, the values are different from those in the tooth profile diagram alone or in a single set of tooth profile curves after being intercepted, but the intervals are equal. In this example, the coordinate values in Table 1 are significantly larger, but it does not affect the application of the intervals after taking the difference. Here, the data that ultimately needs to be used is the pixel interval of 40. Combining with known or already obtained data, such as the coordinate data of the predicted curve and the measured curve at the tooth root position (56.98 microns) and the coordinate data of the measured curve at 56.88 microns, to deduce the coordinate data of the predicted curve at 56.88 microns and the distance between the two curves at this point, that is, the tooth profile tooth root offset, corresponding to Figure 11 the f marked in fαf . It should be understood that fewer or more diameters can be selected to calculate the coordinate position and pixel interval at 56.88 microns to achieve a balance as needed among calculation cost, time, and accuracy.

[0108] In addition to the tooth profile tooth root offset, other gear characteristic quantities that can characterize the gear attributes can also be obtained using the predicted curve. Combining Figures 12 to 15 , a schematic diagram of a deviation curve according to the present invention; a schematic diagram of a smoothed deviation curve according to the present invention; a design schematic diagram of an intercept frame relative to the deviation curve according to the present invention; and a design schematic diagram of a reference line relative to the deviation curve according to the present invention are respectively shown.

[0109] Based on the predicted curve 4 and the measured curve 2 to obtain the gear characteristic quantity, including:

[0110] S35: Obtain a deviation curve 6 based on the deviation between the predicted curve 4 and the measured curve 2;

[0111] S36: Calculate a curve characteristic quantity based on the deviation curve 6 as the gear characteristic quantity, and the curve characteristic quantity includes one or more of the following characteristics:

[0112] Maximum positive offset distance, maximum negative offset distance, curve coverage area, curve variance.

[0113] This technical solution gives other application methods of the predicted curve. By comparing with the measured curve to obtain the deviation curve, and then by analyzing the characteristics of the deviation curve, the corresponding gear characteristic quantity can be inferred. The following briefly introduces the four given characteristics.

[0114] The maximum positive offset distance is the maximum offset distance of the deviation curve above the vertical axis, which characterizes the maximum positive value of the gear deviating from its theoretical position during rotation, that is, whether the tooth profile is convex. This offset distance may lead to poor meshing of the gear, resulting in problems such as noise, vibration, and wear. During the gear design and manufacturing process, the maximum positive offset distance of the gear needs to be considered, and corresponding measures should be taken to reduce or avoid this offset. For example, the offset of the gear can be reduced by improving the manufacturing accuracy of the gear, selecting high-precision processing equipment, or adopting an optimized design, etc.

[0115] The maximum negative offset distance is the maximum offset distance of the deviation curve below the vertical axis, which represents the maximum value of the gear deviating in the opposite direction of its theoretical position during rotation, that is, whether the tooth profile is concave. When the gear deviates during rotation, that is, when the contact point on the tooth surface of the gear deviates in the opposite direction of the theoretical position, the meshing force of the gear will be uneven, resulting in impact and vibration. This uneven meshing force will accelerate the wear and fatigue of the gear and reduce the service life of the gear. Therefore, during the gear design and manufacturing process, the maximum negative offset distance of the gear also needs to be considered, and corresponding measures should be taken to reduce or avoid this deviation. For example, the deviation of the gear can be reduced by improving the manufacturing accuracy of the gear, selecting high-precision processing equipment, or adopting an optimized design, etc.

[0116] The curve coverage area refers to the area covered with the deviation curve as the boundary. The size of this area depends on the shape, position, and range of the curve. This feature can represent the machining error and installation error of the gear. If the area covered by the deviation curve is large, it indicates that the machining error of the gear is large and the accuracy grade of the gear is low; if the area covered by the deviation curve is small, it indicates that the machining error of the gear is small and the accuracy grade of the gear is high. In addition, if the area covered by the deviation curve shows regular changes, such as periodic changes or symmetry changes, etc., it indicates that the installation error of the gear is large; if the area covered by the deviation curve is relatively random, it indicates that the installation error of the gear is small. Therefore, by measuring and calculating the area covered by the deviation curve, the machining error and installation error of the gear can be evaluated, thereby judging the quality and performance of the gear.

[0117] The curve variance is an index used to reflect the degree of dispersion of data fluctuations: if the curve variance is small, it indicates that the data is relatively concentrated and the fluctuations are small; if the curve variance is large, it indicates that the data is relatively dispersed and the fluctuations are large. The curve variance of the deviation curve can represent the magnitude of the random errors generated during the gear manufacturing process. During the gear manufacturing process, due to the influence of various factors, such as machine tool errors, tool wear, heat treatment deformation, etc., the machining errors of each gear will vary. These errors can be regarded as random variables, and their distribution can be described by the deviation curve. If the curve variance of the deviation curve is small, it indicates that the random errors generated during the manufacturing process are small and the precision grade of the gear is high; if the curve variance of the deviation curve is large, it indicates that the random errors generated during the manufacturing process are large and the precision grade of the gear is low. Therefore, by measuring and calculating the curve variance of the deviation curve, the magnitude of the random errors generated during the gear manufacturing process can be evaluated, thereby judging the quality and performance of the gear.

[0118] In summary, through the study of the characteristics of the deviation curve, it is possible to provide a good reference for gear characteristics, thereby providing quantitative guidance for gear quality determination, gear design, machining, installation and other aspects.

[0119] Additionally or alternatively, obtaining the gear characteristic quantity based on the predicted curve 4 and the measured curve 2 further includes:

[0120] S37: Smooth the deviation curve 6;

[0121] S38: Set up an intercepting frame 7 and a reference line 8, where the intercepting frame 7 is used to intercept the deviation curve 6, and the reference line 8 is a line parallel to the horizontal axis;

[0122] S39: Determine whether the part of the deviation curve 6 intercepted by the intercepting frame 7 exists both above and below the reference line 8. If so, the deviation curve 6 is considered an S-shaped curve, and the gear tooth profile is considered S-shaped and used as the gear characteristic quantity.

[0123] The benefits of smoothing include: removing noise and outliers, making the data more stable and reliable; facilitating data analysis; and improving data accuracy. The intercept box is exemplarily a rectangular box in the figure, which is used to intercept a part of the curve, and this intercept box can be moved on the curve to intercept different regions of the curve, and different results may be obtained. In this way, it can be more comprehensive and accurate to determine whether the curve or the intercepted part of the curve is in an S shape. Similarly exemplarily, the reference line is a horizontal axis parallel line with a vertical coordinate of 0, which can be more in line with the actual situation. Of course, according to objective requirements or application scenarios, those skilled in the art can adjust features such as the shape, size of the intercept box, the part of the curve to be intercepted, the shape and position of the reference line. For example, the size of the intercept box opening can be set according to experience, or intercept boxes of different sizes can be set to judge the curve.

[0124] In step S39, if there are parts intercepted by the intercept box both above and below the reference line, and combined with prior knowledge, this situation can also be understood as the intercepted part of the curve fluctuating up and down based on 0, and from the perspective of the horizontal axis, it is in the shape of an S.

[0125] If the deviation curve presents an S shape, it represents that the tooth profile and tooth direction are in an S shape, which may indicate that there are some systematic errors in the manufacturing process, such as machine tool errors, tool wear, etc. These systematic errors may lead to a decrease in the machining accuracy of the gear, affecting the performance and quality of the gear. Therefore, judging whether the deviation curve is in an S shape can provide some information about the possible systematic errors in the gear manufacturing process, and can provide qualitative guidance for gear quality determination, gear design, machining, installation and other links.

[0126] Reference Figure 16 , which shows a module schematic diagram of a measuring device according to the present invention.

[0127] The measuring device 100 is used for gear characteristic quantities. Among them, the measuring device 100 is used to execute any of the above-mentioned measuring methods. The measuring device 100 includes:

[0128] An input module 101, which is used to obtain a gear tooth profile diagram GP. The gear tooth profile diagram GP includes an average curve 1, a measured curve 2 and a marking line 3. Among them, the average curve 1 is discontinuous, the measured curve 2 is continuous, and the marking line 3 is parallel to the horizontal axis of the gear tooth profile diagram GP and intersects the measured curve 2;

[0129] An extraction module 102, which is used to obtain a predicted curve 4 based on the average curve 1 from the gear tooth profile diagram GP. The predicted curve 4 is a continuous curve;

[0130] A calculation module 103, configured to obtain the gear characteristic quantity based on the predicted curve 4 and the measured curve 2.

[0131] Regarding various embodiments of the measuring device and the achievable technical effects, reference can be made to the above explanations regarding the measuring method for interpretation, and no further elaboration will be provided here. It should be understood that since the specific shapes and connection methods of the various components are not the subject matter of the present invention, for the sake of clarity and conciseness, all these components are schematically shown in the form of structural modules. Those skilled in the art can select appropriate module shapes and connection methods, etc. on the inspiration of the structural diagrams. In addition, the given structural diagrams are an embodiment of the present invention, and those skilled in the art can make various modifications without departing from the spirit of the present invention after referring to the diagrams, and these modifications should also be within the protection scope of the present invention.

[0132] According to other aspects of the present disclosure, there are also involved: a computer-readable storage medium on which a computer program is stored, wherein when the computer program is executed by a processor, the above-mentioned any one of the measuring methods is implemented; and a computer device, the computer device includes a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the computer program, the above-mentioned any one of the measuring methods is implemented.

[0133] Similarly, please also refer to the explanations regarding the measuring method to understand the specific embodiments and technical effects of the storage medium and the computer device.

[0134] Those skilled in the art can understand that all or part of the processes in the measurement method of the present invention can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code. It can be understood that this program code includes, but is not limited to, the program code for executing the above-mentioned measurement method. For the sake of illustration, only the part related to the present invention is shown. The computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable storage medium can include: any entity or device, medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0135] In summary, for the tooth profile test report results of, for example, a Klingelnberg measuring instrument, the embodiments of the present disclosure adopt image processing and recognition technologies, can customize and develop a tooth profile feature monitoring algorithm according to the requirements of the business party, extract tooth profile features and realize feature quantification, can realize self-diagnosis of tooth profile and tooth direction, thereby realizing automatic analysis and determination of the test report, can greatly improve the ability of manual determination of tooth profile and tooth direction reports, make up for the lack of information in, for example, bearing tooth profile and tooth direction test reports, reduce the subjective differences in manual determination, timely feedback to the production front line for process quality improvement, reduce the unqualified rate of gears and reduce the probability of NVH occurrence, and finally make the judgment of whether the gear is qualified more clear, improve the accuracy and efficiency of reading bearing gear tooth direction test reports, and greatly help reduce labor costs.

[0136] It should be understood that all the above preferred embodiments are exemplary rather than restrictive, and all kinds of modifications or deformations made by those skilled in the art to the specific embodiments described above under the concept of the present invention should be within the legal protection scope of the present invention.

Claims

1. A method for measuring a characteristic quantity of a gear, characterized in that: The determination method comprises the following steps: Obtaining a gear tooth profile diagram (GP), wherein the gear tooth profile diagram (GP) comprises an average curve (1), a measured curve (2) and a marking line (3), wherein the average curve (1) is discontinuous, the measured curve (2) is continuous, and the marking line (3) is parallel to the horizontal axis of the gear tooth profile diagram (GP) and intersects with the measured curve (2); From the gear profile diagram (GP), a prediction curve (4) based on the average curve (1) is obtained, wherein the prediction curve (4) is a continuous curve; The gear characteristic quantity is obtained based on the predicted curve (4) and the measured curve (2).

2. The measuring method according to claim 1, characterized in that The marking line (3) comprises a first marking line (31) and a second marking line (32) which are parallel to each other, and the acquisition of the prediction curve (4) comprises: Based on the coordinate position of the average curve segment located outside the first marking line (31), an initial prediction curve (41) is obtained; Establishing a cutting line (5), wherein the cutting line (5) is parallel to the first marking line (31) and has a distance from the first marking line (31) in a direction inside the first marking line (31); Based on the number and position of intersections of the intercept line (5) with the average curve (1) and the measured curve (2), the initial prediction curve (41) is updated until the intercept line (5) overlaps with the second marking line (32), and the updating is completed; Based on the updated initial prediction curve (41), the prediction curve (4) is fitted, and the prediction curve (4) spans the first marking line (31) and the second marking line (32).

3. The measuring method according to claim 2, characterized in that Based on the number and positions of intersections of the intercept line (5) with the average curve (1) and the measured curve (2), the initial prediction curve (41) is updated, including: In response to the intercept line (5) having one intersection point with the average curve (1) and the measured curve (2), calculating whether the absolute value of the deviation between the coordinate prediction value of the intersection point and the actual coordinate value is less than a coordinate deviation threshold value; if so, updating the initial prediction curve (41) in combination with the coordinate position of the intersection point; if not, treating the intersection point as a null value, and updating the initial prediction curve (41) accordingly; In response to the fact that there are two intersection points between the intercept line (5) and the average curve (1) and the measured curve (2), the absolute values ​​of the deviations between the coordinate prediction values ​​and the actual coordinates of the two points are calculated respectively, and the intersection point corresponding to the absolute value with the smaller value is selected to update the initial prediction curve (41). The coordinate prediction value is obtained based on the initial prediction curve (41) before updating.

4. The measuring method according to claim 1, characterized in that The acquisition of the prediction curve (4) comprises: removing the background grid of the gear tooth profile graph (GP); acquiring a single set of tooth profile curves; and filtering the background noise of the single set of tooth profile curves.

5. The measuring method according to claim 1, characterized in that The gear characteristic quantity is a tooth profile root deviation, and the gear characteristic quantity is obtained based on the prediction curve (4) and the measured curve (2), including: Obtaining the involute base circle diameter, the involute extension evaluation starting circle diameter, the involute pitch circle diameter and the coordinate position corresponding to the involute pitch circle diameter of the gear tooth profile diagram (GP); Calculating and obtaining the curvature radii corresponding to the involute extension evaluation starting circle diameter and the involute pitch circle diameter respectively; Calculating and obtaining a coordinate position corresponding to the diameter of the starting circle of the involute extension evaluation; The distance between the predicted curve (4) and the measured curve (2) at the starting circle diameter of the involute extension evaluation is calculated and obtained as the tooth profile tooth root offset.

6. The measuring method according to claim 1, characterized in that The gear characteristic quantity is obtained based on the predicted curve (4) and the measured curve (2), including: Obtaining a deviation curve (6) based on the deviation between the predicted curve (4) and the measured curve (2); Based on the deviation curve (6), a curve feature quantity is calculated as the gear feature quantity, and the curve feature quantity includes one or more of the following features: Maximum positive offset distance, maximum negative offset distance, curve coverage area, and curve variance.

7. The measuring method according to claim 6, characterized in that The gear characteristic quantity is obtained based on the predicted curve (4) and the measured curve (2), and further includes: Smoothing the deviation curve (6); A cutting frame (7) and a reference line (8) are set up, wherein the cutting frame (7) is used to cut the deviation curve (6), and the reference line (8) is a line parallel to the horizontal axis; It is determined whether the portion of the deviation curve (6) intercepted by the interception frame (7) exists both above and below the baseline (8). If so, it is considered that the deviation curve (6) is an S-shaped curve, and the gear tooth profile is considered to be S-shaped, which is used as the gear characteristic quantity.

8. The measuring method according to any one of claims 1 to 7, characterized in that The gear profile diagram (GP) is generated from the test report of the Klingelnberg test equipment.

9. A gear characteristic quantity measuring device (100), characterized in that: The measuring device (100) is used to perform the measuring method according to any one of claims 1 to 8, and the measuring device (100) comprises: An input module (101) is used to obtain a gear tooth profile diagram (GP), wherein the gear tooth profile diagram (GP) comprises an average curve (1), a measured curve (2) and a marking line (3), wherein the average curve (1) is discontinuous, the measured curve (2) is continuous, and the marking line (3) is parallel to the horizontal axis of the gear tooth profile diagram (GP) and intersects with the measured curve (2); An extraction module (102) is used to obtain a prediction curve (4) based on the average curve (1) from the gear profile diagram (GP), wherein the prediction curve (4) is a continuous curve; A calculation module (103) is used to obtain the gear characteristic quantity based on the predicted curve (4) and the measured curve (2).

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the measuring method according to any one of claims 1 to 8 is implemented.

11. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the measuring method according to any one of claims 1 to 8 is implemented.

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