Intelligent detection method for automobile gear

Abstract

The invention relates to the technical field of gear detection, in particular to an intelligent detection method for an automobile gear sample, which comprises the following steps: carrying out heat treatment on a gear sample in an automobile gear, and collecting thermal stress parameters in the heat treatment process; establishing a three-dimensional geometric model of the gear sample per unit time in the heat treatment process, and obtaining the maximum geometric deviation value; judging whether the tooth surface defect type of the gear sample is an axial distortion defect type or a heterogeneous phase change defect type according to the maximum geometric deviation value; if the defect type is the axial distortion defect type, determining to adopt asymmetric quenching spraying according to the jerk value difference value of the jerk values of the end surfaces on the two sides, and adjusting the flow of nozzles on the two sides of the end surfaces; if the gear sample is in the heterogeneous phase change defect type, adjusting the cooling phase change time sequence of the gear sample according to the deformation rate ratio of the tooth top deformation rate to the tooth root deformation rate; and the automobile gear is sequentially subjected to a heat treatment process and a cooling process. According to the invention, the accuracy of gear detection and the stability of gear transmission are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gear detection, and in particular to an intelligent detection method for automobile gear samples. BACKGROUND

[0002] In the prior art, three-dimensional scanning equipment is used to obtain gear surface point cloud data, and point cloud processing and geometric modeling technology are combined to detect key geometric parameters such as tooth shape, tooth pitch, tooth direction, tooth thickness, and public normal length, thereby making up for the deficiency of two-dimensional vision in depth information. Mainstream devices include laser triangulation scanning, structured light scanning, and CT scanning. Point cloud denoising, registration, and surface reconstruction are used to convert discrete point clouds into three-dimensional grid models. By comparing the model with a standard gear CAD model, such as deviation calculation based on the iterative closest point, parameters such as tooth shape error and tooth pitch cumulative error are automatically output, and it is determined whether they meet ISO or GB standards.

[0003] Chinese Patent Publication No. CN115165346A discloses an automobile engine gear detection device and detection method, which includes the following steps: driving the standard wheel to rotate by the driving motor; adjusting the guide block of the detection workpiece position, and the guide block drives the detected workpiece gear to approach the standard wheel until the standard wheel is meshed without backlash; rotating the hand wheel to adjust the center distance between the two wheels to the standard center distance position; increasing the rotation speed of the driving motor to its rated speed to check whether the gear pair transmission has abnormal noise; the dial gauge reads out the radial runout parameter of the detected workpiece gear, and the laser displacement sensor detects the radial runout parameter of the detected workpiece gear. If the runout parameter is out of standard, the warning light will alarm. At this time, the rotation speed is lowered, the dial gauge pointer is observed carefully, the out-of-standard tooth is found, and a mark is made. After taking it down and manually polishing, it is detected again. Until there is no abnormal noise and the value meets the standard. It can be seen that the automobile engine gear detection device and detection method have the problems of gear asymmetric deformation and uneven gear tooth surface stress distribution caused by medium coverage difference due to uneven cooling and gear clamping skew during the heat treatment process, which further leads to tooth shape distortion, increased meshing noise, and transmission stability. SUMMARY

[0004] To this end, the present application provides an intelligent detection method for automobile gear samples to overcome the problems of gear asymmetric deformation and uneven gear tooth surface stress distribution caused by medium coverage difference due to uneven cooling and gear clamping skew during the heat treatment process, which further leads to tooth shape distortion, increased meshing noise, and transmission stability in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides an intelligent detection method for automobile gear samples, which includes:

[0006] The heat treatment is performed on a gear sample in a gear of an automobile, and a thermal stress parameter in the heat treatment process is collected, wherein the thermal stress parameter includes a deformation rate of a dedendum, a deformation rate of a addendum, and a run-out of two side end faces of the gear sample at an end time of the heat treatment, and geometric data of the gear sample;

[0007] A three-dimensional geometric model of the gear sample per unit time in the heat treatment process is established based on the geometric data, and compared with a standard gear sample model to obtain a maximum geometric deviation amount;

[0008] Whether a tooth surface defect type of the gear sample is an axial distortion defect type or a non-uniform phase change defect type is determined according to the maximum geometric deviation amount;

[0009] If the tooth surface defect type of the gear sample is the axial distortion defect type, then a nozzle flow rate of two sides of the end face is determined according to a run-out difference of the run-out of the two side end faces, and adjusted.

[0010] If the tooth surface defect type of the gear sample is the non-uniform phase change defect type, then a cooling phase change timing of the gear sample is adjusted according to a deformation rate ratio of the deformation rate of the addendum and the deformation rate of the dedendum.

[0011] The automobile gear is sequentially subjected to a heat treatment process and a cooling process according to the nozzle flow rate of the two sides of the end face or the cooling phase change timing of the gear sample.

[0012] Further, the geometric deviation amount is an average value of straight line deviation distances of coordinate points between the three-dimensional geometric model and the standard gear sample model.

[0013] Further, the maximum geometric deviation amount is a maximum value of the geometric deviation amounts of the three-dimensional geometric model and the standard gear sample model detected per unit time in the heat treatment process.

[0014] Further, if the maximum geometric deviation amount is greater than or equal to a preset geometric deviation amount, and a deviation amount angle of the maximum geometric deviation amount is less than a preset angle, then it is determined that the tooth surface defect type of the gear sample is the axial distortion defect type.

[0015] If the maximum geometric deviation amount is greater than or equal to the preset geometric deviation amount, and the deviation amount angle is greater than or equal to the preset angle, then it is determined that the tooth surface defect type of the gear sample is the non-uniform phase change defect type.

[0016] Further, the deviation amount angle is an acute angle included angle between a direction of a sum vector of all coordinate points and an end face of the gear sample when the maximum geometric deviation amount occurs.

[0017] Further, the non-symmetrical quenching spray is adopted, and the flow rates of the nozzles on both sides of the end face are adjusted, including:

[0018] If the tooth surface defect type of the gear sample is the axial distortion defect type, a runout difference value of the runouts of the two end faces is obtained;

[0019] If the runout difference value is greater than or equal to a preset difference value, the non-symmetrical quenching spray is adopted.

[0020] The flow rate of the nozzle on the side of the end face with a larger runout is greater than the flow rate of the nozzle on the side of the end face with a smaller runout.

[0021] Further, the runouts of the two end faces of the gear sample are the maximum displacement amounts of a plurality of measurement points on the end face relative to an ideal plane of the vertical inner hole axis after the two end faces of the gear rotate one circle around the inner hole axis of the gear at the end of the heat treatment;

[0022] The runout difference value is an absolute value of the difference between the runouts of the two end faces.

[0023] Further, the cooling phase change sequence of the gear sample is adjusted, including:

[0024] If the tooth surface defect type of the gear sample is the non-uniform phase change defect type, a deformation rate ratio of the tooth tip deformation rate and the tooth root deformation rate is obtained;

[0025] The deformation rate ratio is compared with a preset rate ratio;

[0026] If the deformation rate ratio is greater than or equal to the preset rate ratio, the cooling phase change sequence of the gear sample is adjusted from the whole cooling to the tooth tip first and then the tooth root.

[0027] Further, the deformation rate ratio is the ratio of the tooth tip deformation rate to the tooth root deformation rate.

[0028] Further, the cooling phase change sequence of the tooth tip first and then the tooth root further satisfies that when the deformation rate ratio is greater than or equal to the preset rate ratio, the tooth tip cooling phase change time is increased, and the start time of the tooth root cooling is delayed.

[0029] Compared with the prior art, the method has the beneficial effects that the method collects the thermal stress parameters of the gear sample in the heat treatment process, including the deformation rate of the tooth root, the deformation rate of the tooth top, the runout of the two side end faces and the geometric data at the end time of the heat treatment, so that the monitoring and evaluation of the deformation process of the gear in the heat treatment are realized; the three-dimensional geometric model of the gear sample in the heat treatment process is established and compared with the standard gear sample model, the maximum geometric deviation is obtained, and then it is accurately judged whether the gear sample has axial distortion defects or non-uniform phase change defects, so that the precision and efficiency of gear defect identification are improved; through identification of the axial distortion defect, the non-symmetrical quenching spraying is implemented according to the difference of the runout of the two side end faces, the thermal deformation is compensated by increasing the nozzle flow of the side with larger runout, the uniform spraying mode ignores the medium coverage difference caused by the clamping skew of the gear, the non-symmetrical quenching spraying mode compensates the non-uniform thermal deformation of the gear caused by the clamping skew, and the uniformity of the stress distribution of the gear surface is improved; through identification of the non-uniform phase change defect, the cooling lag area is identified, the cooling phase change timing is adjusted according to the ratio of the deformation rate of the tooth top to the tooth root, the phased cooling of the tooth top first and then the tooth root is adopted, that is, the tooth top cooling time is prolonged and the tooth root cooling start time is delayed, so that the tooth root obtains strengthened cooling in the austenite stable zone, the tooth surface cracks caused by traditional overall cooling are avoided, the deformation is solidified when the room temperature is detected, the deformation transmission to the cold state is blocked, the tooth profile waviness distortion is inhibited, and the tooth surface precision and transmission stability of the gear sample after cooling phase change are improved.

[0030] Further, the method sets the maximum geometric deviation and the deviation angle of the maximum geometric deviation, and then judges the deformation of the gear sample in different stages affected by thermal stress in the heat treatment process; the deviation angle as the included angle between the vector direction of the maximum geometric deviation and the acute angle of the end face of the gear sample can effectively reflect the directional characteristics of the deformation, when the angle is less than the preset angle, it indicates that the deformation is mainly distributed along the axial direction, which meets the characteristics of the axial distortion defect, otherwise it is the non-uniform phase change defect, through distinguishing the overall bending deformation caused by the clamping skew and the local structure distortion caused by the difference of the material phase change rate, the accuracy of the gear detection is improved.

[0031] Further, when the axial distortion defect type is determined, the nozzle flow is adjusted according to the difference of the runout of the two side end faces, the non-symmetrical quenching spraying strategy is adopted, the end face asymmetric deformation caused by the clamping skew or the uneven medium coverage is compensated, so that the runout of the gear end face is reduced and the form and position accuracy of the gear is improved.

[0032] Further, the method determines the type of tooth surface defect, and adjusts the cooling phase change timing according to the deformation rate ratio of the tooth top and the tooth root when the non-uniform phase change defect type is determined, adopts the cooling strategy of the tooth top first and then the tooth root, and dynamically adjusts the cooling time and the starting time, so that the phase change process is more uniform, the problem of uneven stress distribution of the tooth surface is reduced, the deformation rate of the tooth top and the tooth root of the gear sample in the cooling phase change process tends to be consistent, the profile undulation distortion caused by the too large local deformation rate difference is avoided, the meshing noise of the gear in the transmission process is reduced, and the overall transmission stability is improved.

[0033] Further, the method determines the type of tooth surface defect, and adjusts the cooling phase change timing according to the deformation rate ratio of the tooth top and the tooth root when the non-uniform phase change defect type is determined, adopts the cooling strategy of the tooth top first and then the tooth root, and dynamically adjusts the cooling time and the starting time, so that the phase change process is more uniform, the problem of uneven stress distribution of the tooth surface is reduced, the deformation rate of the tooth top and the tooth root of the gear sample in the cooling phase change process tends to be consistent, the profile undulation distortion caused by the too large local deformation rate difference is avoided, the meshing noise of the gear in the transmission process is reduced, and the overall transmission stability is improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The figure is a flowchart of the intelligent detection method for the automobile gear sample of the embodiment of the present application.

[0035] Figure 2 The figure is a flowchart of the intelligent detection method for the automobile gear sample of the embodiment of the present application, which adopts the asymmetric quenching spray and adjusts the nozzle flow rate of the two sides of the end face.

[0036] Figure 3 The figure is a flowchart of the intelligent detection method for the automobile gear sample of the embodiment of the present application, which adjusts the cooling phase change timing of the gear sample.

[0037] Figure 4 The figure is a flowchart of the intelligent detection method for the automobile gear sample of the embodiment of the present application, which determines the type of tooth surface defect. DETAILED DESCRIPTION

[0038] In order to make the purpose and advantages of the present application more clear and explicit, the present application is further described below in combination with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the protection scope of the present application.

[0039] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and are not used to limit the protection scope of the present application.

[0040] It should be noted that in the description of the present application, the terms indicating the direction or positional relationship of "upper", "lower", "left", "right", "inner", "outer" and the like are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0041] In addition, it should also be noted that in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , which are respectively the overall flowchart of the intelligent detection method for automobile gear sample of the embodiment of the present application, the flowchart of adjusting the nozzle flow rate of the two sides of the end face by using asymmetric quenching spray, the flowchart of adjusting the cooling phase change timing of the gear sample, and the flowchart of determining the gear surface defect type. The intelligent detection method for automobile gear sample of the present application comprises:

[0043] The gear sample in the automobile gear is subjected to heat treatment, and the thermal stress parameters in the heat treatment process are collected, wherein the thermal stress parameters include the tooth root deformation rate, the tooth tip deformation rate, and the runout of the two sides of the end face of the gear sample at the end of the heat treatment, and the geometric data of the gear sample;

[0044] A three-dimensional geometric model of the gear sample per unit time during the heat treatment is established based on the geometric data, and is compared with a standard gear sample model to obtain the maximum geometric deviation;

[0045] According to the maximum geometric deviation, it is determined whether the gear surface defect type of the gear sample is the axial distortion defect type or the non-uniform phase change defect type;

[0046] If the gear surface defect type of the gear sample is the axial distortion defect type, the nozzle flow rate of the two sides of the end face is adjusted by using asymmetric quenching spray according to the runout difference of the runout of the two sides of the end face;

[0047] If the gear surface defect type of the gear sample is the non-uniform phase change defect type, the cooling phase change timing of the gear sample is adjusted according to the deformation rate ratio of the tooth tip deformation rate and the tooth root deformation rate.

[0048] The heat treatment process and the cooling process are sequentially performed on the automobile gear according to the flow of the nozzles on both sides of the end face or the cooling phase change timing of the gear sample.

[0049] Specifically, the heat treatment and cooling process of the gear sample in the automobile gear comprises:

[0050] The gear sample is fixed on the manipulator;

[0051] The manipulator controls the rotation of the gear sample in the heating furnace;

[0052] The gear sample is sprayed by the double-zone quenching tank in the heating furnace to complete the heat treatment of the gear sample;

[0053] The heat-treated gear sample is cooled by the annular cooling nozzle.

[0054] Specifically, the geometric data includes the three-dimensional size, the number of teeth, the module, the pressure angle, the tooth width, and the inner hole diameter of the gear sample.

[0055] Specifically, the geometric data can be collected by a three-coordinate measuring machine or an industrial CT scanner;

[0056] The tooth root deformation rate and the tooth tip deformation rate are detected by a plurality of laser displacement sensors arranged in the heating furnace;

[0057] The runout of the two end faces is detected by an end face runout measuring table.

[0058] Specifically, the three-dimensional geometric model is constructed by a finite element analysis software or SolidWorks API;

[0059] The geometric deviation is calculated by the straight-line distance between the corresponding coordinate points of the two model surfaces after aligning the three-dimensional geometric model with the standard gear model in the model software, for example, the standard model surface point coordinates are (x s ,y s ,z s ), and the real-time model corresponding point is (xr, yr, zr),

[0060] The geometric deviation is Wherein, a is the geometric deviation, and n is the number of coordinate points.

[0061] In the implementation, the method of the application realizes the monitoring and evaluation of the deformation process of the gear during heat treatment by collecting the thermal stress parameters of the gear sample during heat treatment, including the deformation rate of the tooth root, the deformation rate of the tooth top, and the runout of the two side faces, and the geometric data at the end of heat treatment; the maximum geometric deviation is obtained by establishing a three-dimensional geometric model of the gear sample during heat treatment and comparing it with the standard gear sample model, and then the axial distortion defect or the non-uniform phase change defect of the gear sample is accurately judged, and the precision and efficiency of gear defect identification are improved; by identifying the axial distortion defect, the non-symmetrical quenching spray is implemented according to the difference of the runout of the two side faces, the flow of the nozzle on the side with larger runout is increased to compensate for the thermal deformation, the uniform spraying mode ignores the difference in medium coverage caused by the clamping skew of the gear, the non-symmetrical quenching spray mode compensates for the non-uniform thermal deformation of the gear caused by the clamping skew, and the uniformity of the stress distribution on the gear surface is improved; by identifying the non-uniform phase change defect, the cooling lag area is identified, the cooling phase change timing is adjusted according to the ratio of the deformation rate of the tooth top to the tooth root, and the gear is cooled in stages, i.e. the tooth top is cooled first and then the tooth root, which prolongs the cooling time of the tooth top and delays the start time of the cooling of the tooth root, so that the tooth root obtains strengthened cooling in the austenite stable zone, avoids the tooth surface cracks caused by traditional overall cooling, and avoids the deformation solidification during room temperature detection, which blocks the transmission of deformation to the cold state and inhibits the distortion of the gear profile waviness, and the precision of the gear surface after cooling phase change and the transmission stability of the gear sample are improved.

[0062] Specifically, the geometric deviation is the average value of the straight line deviation distance of the coordinate points between the three-dimensional geometric model and the standard gear sample model.

[0063] Specifically, the maximum geometric deviation is the maximum value of the geometric deviation of the three-dimensional geometric model and the standard gear sample model detected per unit time during heat treatment.

[0064] In the implementation, the method of the application judges the deformation of the gear sample at different stages affected by thermal stress during heat treatment by setting the maximum geometric deviation and the deviation angle thereof, and the deviation angle as the included angle between the direction vector of the maximum geometric deviation and the acute angle of the end face of the gear sample can effectively reflect the directional characteristics of the deformation. When the deviation angle is less than the preset angle, it indicates that the deformation is mainly distributed along the axial direction, which is consistent with the characteristics of the axial distortion defect, otherwise it is a non-uniform phase change defect. By distinguishing the overall bending deformation caused by clamping skew and the local structure distortion caused by the difference in material phase change rate, the accuracy of gear detection is improved.

[0065] Specifically, if the maximum geometric deviation is greater than or equal to the preset geometric deviation, and the deviation angle of the maximum geometric deviation is less than the preset angle, it is determined that the gear surface defect type of the gear sample is the axial distortion defect type.

[0066] If the maximum geometric deviation amount is greater than or equal to the preset geometric deviation amount, and the deviation angle is greater than or equal to the preset angle, it is determined that the tooth surface defect type of the gear sample is the non-uniform phase change defect type.

[0067] Specifically, in the case of the automobile gear being a heavy load gear with a module greater than 3 mm and the material density of the automobile gear being 7.85 g / cm 3 , the preset geometric deviation amount generally has a value range of [0.1 mm, 0.4 mm], and a preferred embodiment of the preset geometric deviation amount is 0.22 mm.

[0068] It can be understood by those skilled in the art that the optional range and the preferred embodiment of the preset geometric deviation amount provided in the embodiment are the best values selected for the effect of the technical problem solved by the technical scheme of the present application in the case of the automobile gear being a heavy load gear with a module greater than 3 mm and the material density of the automobile gear being 7.85 g / cm 3 . In actual application or experiment, those skilled in the art can adaptively adjust the preset geometric deviation amount according to the actual application environment and application scenario.

[0069] Specifically, the deviation angle is an acute angle between the direction of the sum vector of all coordinate points when the maximum geometric deviation amount occurs and the end face of the gear sample.

[0070] In implementation, the present application compensates for the asymmetric deformation of the end face due to clamping skew or uneven medium coverage by adopting an asymmetric quenching spraying strategy to adjust the nozzle flow according to the difference between the two-side end face runout amounts when it is determined to be the axial torsion defect type, thereby reducing the gear end face runout amount and improving the form and position accuracy of the gear.

[0071] Specifically, the asymmetric quenching spraying and the adjustment of the nozzle flow of the two sides of the end face include:

[0072] If the tooth surface defect type of the gear sample is the axial torsion defect type, the runout difference between the runout amounts of the two sides of the end face is obtained.

[0073] If the runout difference is greater than or equal to a preset difference, asymmetric quenching spraying is adopted.

[0074] The nozzle flow of the side of the end face with a larger runout amount is adjusted to be greater than the nozzle flow of the side of the end face with a smaller runout amount.

[0075] Specifically, the runout amount of the two sides of the end face of the gear sample is the maximum displacement amount of a plurality of measurement points on the end face relative to the ideal plane of the vertical inner hole axis when the two sides of the end face of the gear rotate one revolution around the inner hole axis of the gear at the end of heat treatment.

[0076] The run-out difference value is an absolute value of a difference between run-out values of the two end faces.

[0077] Specifically, in the case of the automobile gear being a heavy load gear with a module greater than 3 mm, the material density of the automobile gear being 7.85 g / cm 3 , and the area of the end face of the automobile gear being not less than 40 cm 2 , the preset difference value is generally in the range of [0.05 mm, 0.2 mm], and the preferred embodiment of the preset difference value is 0.1 mm.

[0078] It can be understood by those skilled in the art that the optional range and the preferred embodiment of the preset difference value provided in the embodiment are the values best for the effect of the technical problem solved by the technical scheme of the present application in the case of the automobile gear being a heavy load gear with a module greater than 3 mm, the material density of the automobile gear being 7.85 g / cm 3 , and the area of the end face of the automobile gear being not less than 40 cm 2 . In actual application or experiment, those skilled in the art can adaptively adjust the preset difference value according to the actual application environment and application scenario.

[0079] Specifically, the nozzle flow rate of the larger side of the adjusted end face run-out = the nozzle flow rate before adjustment x (1+tanh run-out difference value);

[0080] The nozzle flow rate of the smaller side of the adjusted end face run-out = the nozzle flow rate before adjustment x (1-tanh run-out difference value);

[0081] For example, the run-out difference value is 0.2, and the nozzle flow rate before adjustment is 100 L / min. Then, the nozzle flow rate of the larger side of the adjusted end face run-out = 100 L / min x (1+tanh 0.2) ≈ 119.74 L / min, and the nozzle flow rate of the smaller side of the adjusted end face run-out = 100 L / min x (1-tanh 0.2) ≈ 80.26 L / min.

[0082] In implementation, the hyperbolic tangent function tanh is used to realize smooth transition of flow rate, avoiding pressure impact.

[0083] In the implementation, the method of the application adjusts the cooling phase change timing according to the ratio of the deformation rates of the tooth tip and the tooth root when it is determined that the non-uniform phase change defect type, adopts the cooling strategy of the tooth tip first and the tooth root later, and dynamically adjusts the cooling time and the starting time, so that the phase change process is more uniform, the problem of uneven stress distribution on the tooth surface is reduced, the deformation rates of the tooth tip and the tooth root of the gear sample in the cooling phase change process tend to be consistent, the profile undulation distortion caused by the too large local deformation rate difference is avoided, the meshing noise of the gear in the transmission process is reduced, and the overall transmission stability is improved.

[0084] Specifically, the cooling phase change timing of the gear sample is adjusted, including:

[0085] If the tooth surface defect type of the gear sample is the non-uniform phase change defect type, the deformation rate ratio of the tooth tip deformation rate and the tooth root deformation rate is obtained;

[0086] The deformation rate ratio is compared with a preset rate ratio;

[0087] If the deformation rate ratio is greater than or equal to the preset rate ratio, the cooling phase change timing of the tooth tip first and the tooth root later is adjusted by the overall cooling of the gear sample.

[0088] Specifically, the deformation rate ratio is the ratio of the tooth tip deformation rate and the tooth root deformation rate.

[0089] Specifically, the automobile gear is a heavy load gear with a module greater than 3 mm, the material density of the automobile gear is 7.85 g / cm 3 , and the end surface area of the automobile gear is not less than 40 cm 2 .

[0090] Those skilled in the art can understand that the optional range and the preferred embodiment of the preset rate ratio provided in the embodiment are the best values selected for the technical problem solved by the technical scheme of the application under the condition that the automobile gear is a heavy load gear with a module greater than 3 mm, the material density of the automobile gear is 7.85 g / cm 3 , and the end surface area of the automobile gear is not less than 40 cm 2 . In actual application or experiment, those skilled in the art can adaptively adjust the preset rate ratio according to the actual application environment and application scene.

[0091] Specifically, the cooling phase change timing of the tooth tip first and the tooth root later also satisfies that when the deformation rate ratio is greater than or equal to the preset rate ratio, the tooth tip cooling phase change time is increased, and the starting time of the tooth root cooling is delayed.

[0092] Specifically, the increment of the tip cooling phase change time is not more than 3s;

[0093] If the difference between the deformation rate ratio and the preset rate ratio is within 0.01, the tip cooling phase change time is increased by 0.5s, and the delay time of the delayed start time of the root cooling is increased by 0.5s, if the difference between the deformation rate ratio and the preset rate ratio exceeds 0.01, and for each increase of 0.01, the tip cooling phase change time is increased by 0.2s, and the delay time of the delayed start time of the root cooling is increased by 0.5s, if the tip cooling phase change time is increased to 3s, the tip cooling phase change time is always kept at 3s;

[0094] For example, the deformation rate ratio and the preset rate ratio are 0.03, the tip cooling phase change time is 1s, and the start time of the root cooling is not delayed, then the tip cooling phase change time is increased to 1s+0.5s+0.2s*2=1.9s, and the start time of the root cooling is delayed by 0.5s*3=1.5s.

[0095] In the implementation, the method of the present application adjusts the cooling phase sequence according to the deformation rate ratio of the tip and the root when it is determined that the non-uniform phase change defect type, adopts the cooling of the tip first and then the root, and adjusts the cooling time and the start time, so that the phase change process is more uniform, the stress conflict between the martensite phase change expansion of the tip and the pearlite transformation shrinkage of the root is relieved, the stress concentration phenomenon caused by the synchronous cooling rate of the tip and the root in the traditional overall cooling is avoided, the microcracks on the gear surface are reduced by controlling the phase change sequence in stages, and the transmission reliability of the gear is further improved.

[0096] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after these changes or replacements will fall within the protection scope of the present application.

Claims

1. An intelligent detection method for automobile gear samples, characterized in that, The method comprises the following steps: heat treating a gear sample in a gear of an automobile, and collecting a thermal stress parameter in the heat treatment process, wherein the thermal stress parameter comprises a dedendum deformation rate, a addendum deformation rate, and a runout of two end faces of the gear sample at the end of the heat treatment, and geometric data of the gear sample; establishing a three-dimensional geometric model of the gear sample per unit time in the heat treatment process based on the geometric data, and comparing the three-dimensional geometric model with a standard gear sample model to obtain a maximum geometric deviation amount; determining whether a tooth surface defect type of the gear sample is an axial distortion defect type or a non-uniform phase change defect type according to the maximum geometric deviation amount; if the tooth surface defect type of the gear sample is the axial distortion defect type, determining to use asymmetric quenching spraying and adjusting nozzle flow rates of the two end faces according to a runout difference of the runout of the two end faces; if the tooth surface defect type of the gear sample is the non-uniform phase change defect type, adjusting a cooling phase change timing of the gear sample according to a deformation rate ratio of the addendum deformation rate and the dedendum deformation rate; respectively according to the nozzle flow rates of the two end faces or the cooling phase change timing of the gear sample, sequentially performing a heat treatment process and a cooling process on the automobile gear.

2. The automobile gear sample intelligent detection method according to claim 1, characterized in that, The geometric deviation amount is an average value of straight line deviation distances of coordinate points between the three-dimensional geometric model and the standard gear sample model.

3. The automobile gear sample intelligent detection method according to claim 2, characterized in that, The maximum geometric deviation amount is a maximum value of the geometric deviation amounts of the three-dimensional geometric model and the standard gear sample model detected per unit time in the heat treatment process.

4. The automobile gear sample intelligent detection method according to claim 3, characterized in that, if the maximum geometric deviation amount is greater than or equal to a preset geometric deviation amount, and a deviation amount deflection angle of the maximum geometric deviation amount is less than a preset angle, it is determined that the tooth surface defect type of the gear sample is the axial distortion defect type; if the maximum geometric deviation amount is greater than or equal to the preset geometric deviation amount, and the deviation amount deflection angle is greater than or equal to the preset angle, it is determined that the tooth surface defect type of the gear sample is the non-uniform phase change defect type.

5. The automobile gear sample intelligent detection method according to claim 4, characterized in that, The deviation amount deflection angle is an acute angle included angle between a direction of a sum vector of all coordinate points and an end face of the gear sample when the maximum geometric deviation amount occurs.

6. The automobile gear sample intelligent detection method according to claim 5, characterized in that, The method for using asymmetric quenching spraying and adjusting nozzle flow rates of the two end faces comprises the following steps: if the tooth surface defect type of the gear sample is the axial distortion defect type, obtaining a runout difference of the runout of the two end faces; if the runout difference is greater than or equal to a preset difference, using asymmetric quenching spraying; adjusting the nozzle flow rate of the side with a larger runout of the end face to be greater than the nozzle flow rate of the side with a smaller runout of the end face.

7. The automobile gear sample intelligent detection method according to claim 6, characterized in that, The runout of the two end faces of the gear sample is a maximum displacement amount of a plurality of measurement points on the end face relative to an ideal plane of a vertical inner hole axis after the two end faces of the gear rotate one circle around an inner hole axis of the gear at the end of the heat treatment; the runout difference is an absolute value of a difference between the runouts of the two end faces.

8. The automobile gear sample intelligent detection method according to claim 7, characterized in that, The method for adjusting the cooling phase change timing of the gear sample comprises the following steps: if the tooth surface defect type of the gear sample is the non-uniform phase change defect type, obtaining a deformation rate ratio of the addendum deformation rate and the dedendum deformation rate; comparing the deformation rate ratio with a preset rate ratio; If the deformation rate ratio is greater than or equal to the preset rate ratio, the overall cooling adjustment of the gear sample is adjusted to the cooling phase sequence of first tooth tip and then tooth root.

9. The automobile gear sample intelligent detection method according to claim 8, characterized in that, The deformation rate ratio is the ratio of the tooth tip deformation rate and the tooth root deformation rate.

10. The automobile gear sample intelligent detection method according to claim 9, characterized in that, The cooling phase sequence of first tooth tip and then tooth root also satisfies that when the deformation rate ratio is greater than or equal to the preset rate ratio, the tooth tip cooling phase time is increased, and the start time of tooth root cooling is delayed.

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