A method and apparatus for bending fatigue testing of a gear

Abstract

This application provides a method and apparatus for testing the bending fatigue of gears. The method includes: determining a pulse load applied to the gear teeth by a testing device based on the tooth root bending stress; during the application of the pulse load to the gear teeth, determining whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold, wherein the tooth surface temperature is the temperature at the point of application of the load on the tooth surface; if the temperature difference is less than the first threshold, continuing to apply the pulse load to the gear teeth until the gear teeth reach a failure condition, wherein the failure condition includes: tooth root fracture or tooth surface plastic deformation. The testing method provided by this application can avoid test results containing cases where the tooth surface temperature deviates significantly from the ambient temperature, reducing test errors caused by tooth surface temperature rise.

Description

Technical Field

[0001] This application relates to the field of gear testing technology, and in particular to a method and apparatus for testing the bending fatigue of gears. Background Technology

[0002] Gear drives offer advantages such as smooth operation, constant transmission ratio, and low cost, making them widely used in various industrial sectors. By understanding the bending fatigue life of gears in advance, operators can prevent them from reaching their bending fatigue strength limit, thereby reducing losses to machinery caused by gear failure.

[0003] Current gear bending fatigue testing employs a single-tooth loading method, where a pressure head cyclically applies pulsed loads to the gear teeth to determine the number of pulsed load cycles (i.e., bending fatigue life) required for tooth failure (e.g., tooth root fracture or tooth surface plastic deformation). This method primarily targets metal gears. Compared to metal gears, plastic gears exhibit higher sensitivity to temperature changes in their mechanical properties; that is, temperature variations affect the fatigue life of plastic gears. However, during the application of pulsed loads to the teeth, excessively high pulse frequencies can cause the contact area between the tooth surface and the pressure head to heat up. This results in test results that do not reflect the set ambient temperature, introducing significant errors and impacting the accuracy of the test results. Summary of the Invention

[0004] This application provides a method and apparatus for testing the bending fatigue of gears, which can avoid test results that include large deviations between the tooth surface temperature and the ambient temperature, and reduce test errors caused by the temperature rise of the gear tooth surface.

[0005] To address the aforementioned problems, in a first aspect, embodiments of this application provide a method for testing the bending fatigue of gears. This method includes: determining a pulse load applied to the gear teeth by a testing device based on the tooth root bending stress; during the application of the pulse load to the gear teeth, determining whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold, where the tooth surface temperature is the temperature at the load application point on the tooth surface; if the temperature difference is less than the first threshold, continuing to apply the pulse load to the gear teeth until the gear teeth reach a failure condition, wherein the failure condition includes: tooth root fracture or tooth surface plastic deformation.

[0006] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: if the temperature difference is greater than or equal to the first threshold, adjusting the first pulse frequency of the applied pulse load to a second pulse frequency, wherein the second pulse frequency is less than the first pulse frequency; or, if the temperature difference is greater than or equal to the first threshold, turning on the cooling device, and turning off the cooling device when the temperature difference is less than the first threshold, wherein the cooling device is used to reduce the tooth surface temperature.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, determining the pulse load applied to the gear teeth by the testing device based on the tooth root bending stress includes: determining the tooth thickness at the critical section, the load angle at the load application point, and the bending lever arm at the load application point based on the detected basic parameters of the gear, wherein the basic parameters are used to determine the dimensions of the gear; and determining the maximum value of the pulse load using the following formula based on the tooth root bending stress, the tooth thickness at the critical section, the load angle at the load application point, the tooth width, and the bending lever arm at the load application point:

[0008]

[0009] Among them, F n Where b is the maximum value of the pulse load, and b is the tooth width of the gear tooth, S Fn σ is the tooth thickness of the gear tooth at the critical section. F α is the bending stress at the tooth root. Fen h is the load angle at the point of application of the load. Fe The bending lever arm at the point of application of the load; the minimum value of the pulse load is determined according to the maximum value of the pulse load, wherein the minimum value is the product of the maximum value and the stress proportionality coefficient.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, after the gear tooth reaches the failure condition, the method further includes: storing the failure mode of the gear under the ambient temperature and the tooth root bending stress and the number of cycles of the pulse load, wherein the failure mode includes: tooth root fracture or tooth surface plastic deformation.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, after the tooth reaches the failure condition, the method further includes: updating the tooth root bending stress, the updated tooth root bending stress being used to determine the pulse load applied by the testing device to the test tooth of the gear.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, updating the tooth root bending stress includes: updating the tooth root bending stress if the number of cycles of the pulse load is less than a second threshold.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the basic parameters of the gear include: root circle diameter, common normal length, number of teeth spanned by the common normal, number of teeth, normal number of teeth, module, normal module, pressure angle tilt error, pressure angle tilt error evaluation length, pressure angle, normal pressure angle, root fillet radius, base circle diameter, displacement coefficient, and pitch circle radius.

[0014] Secondly, this application also provides a gear bending fatigue testing device, the testing device comprising: a determining module, configured to determine the pulse load applied to the gear teeth by the testing device based on the tooth root bending stress; the determining module is further configured to determine, during the process of applying the pulse load to the gear teeth, whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold, wherein the tooth surface temperature is the temperature at the load application point on the tooth surface; and a processing module, configured to continue applying the pulse load to the gear teeth if the temperature difference is less than the first threshold, until the gear teeth reach the failure condition, wherein the failure condition includes: tooth root fracture or tooth surface plastic deformation.

[0015] In conjunction with the second aspect, in some implementations of the second aspect, the processing module is further configured to: if the temperature difference is greater than or equal to the first threshold, adjust the first pulse frequency of the applied pulse load to a second pulse frequency, wherein the second pulse frequency is less than the first pulse frequency; or, if the temperature difference is greater than or equal to the first threshold, turn on the cooling device, and turn off the cooling device when the temperature difference is less than the first threshold, wherein the cooling device is used to reduce the tooth surface temperature.

[0016] In conjunction with the second aspect, in some implementations of the second aspect, the determining module is specifically used to: determine the tooth thickness at the critical section, the load angle at the load application point, and the bending lever arm at the load application point based on the detected basic parameters of the gear, wherein the basic parameters are used to determine the size of the gear; and determine the maximum value of the pulse load using the following formula based on the tooth root bending stress, the tooth thickness at the critical section, the load angle at the load application point, the tooth width, and the bending lever arm at the load application point:

[0017]

[0018] Among them, Fn Where b is the maximum value of the pulse load, and b is the tooth width of the gear tooth, S Fn σ is the tooth thickness of the gear tooth at the critical section. F α is the bending stress at the tooth root. Fen h is the load angle at the point of application of the load. Fe The bending lever arm at the point of application of the load; the minimum value of the pulse load is determined according to the maximum value of the pulse load, wherein the minimum value is the product of the maximum value and the stress proportionality coefficient.

[0019] In conjunction with the second aspect, in some implementations of the second aspect, the testing device further includes a storage module. After the gear tooth reaches the failure condition, the storage module is used to: store the failure mode of the gear under the ambient temperature and the tooth root bending stress and the number of cycles of the pulse load, wherein the failure mode includes: tooth root fracture or tooth surface plastic deformation.

[0020] In conjunction with the second aspect, in some implementations of the second aspect, after the gear tooth reaches the failure condition, the processing module is further configured to: update the tooth root bending stress, the updated tooth root bending stress being used to determine the pulse load applied by the testing device to the gear tooth under test.

[0021] In conjunction with the second aspect, in some implementations of the second aspect, the processing module is specifically used to: update the tooth root bending stress if the number of cycles of the pulse load is less than the second threshold.

[0022] In conjunction with the second aspect, in some implementations of the second aspect, the basic parameters of the gear include: root circle diameter, common normal length, number of teeth spanned by the common normal, number of teeth, normal number of teeth, module, normal module, pressure angle tilt error, pressure angle tilt error evaluation length, pressure angle, normal pressure angle, root fillet radius, base circle diameter, displacement coefficient, and pitch circle radius.

[0023] Thirdly, this application also provides a gear bending fatigue testing device, including at least one processor, the at least one processor being coupled to a memory to read and execute instructions in the memory to implement the method provided in any of the possible designs in the first aspect above.

[0024] Optionally, the test device also includes the memory.

[0025] Fourthly, this application also provides a computer-readable storage medium storing a computer program that, when run on a computer, causes the computer to perform the method provided in any of the possible designs in the first aspect.

[0026] Fifthly, embodiments of this application also provide a computer program product containing instructions that, when run on a computer, cause the computer to perform the method provided in any of the possible designs in the first aspect.

[0027] The gear bending fatigue testing method provided in this application first determines the pulse load applied to the gear teeth by the testing device based on the tooth root bending stress. Then, the determined pulse load is applied to the teeth, and during the application of the pulse load, it is determined whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold, i.e., whether the deviation between the tooth surface temperature and the ambient temperature is too large. If the temperature difference is less than the first threshold, the pulse load is continued to be applied to the teeth until the failure condition is reached. This method, by only continuing to apply the pulse load when the temperature difference is less than the first threshold, avoids test results including cases where the tooth surface temperature deviates significantly from the ambient temperature, reduces test errors caused by tooth surface temperature rise, and improves the accuracy of the test results. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic flowchart of the gear bending fatigue test method provided in the embodiments of this application.

[0030] Figure 2 This is a schematic diagram of the force analysis of the gear teeth provided in the embodiments of this application.

[0031] Figure 3 This is a schematic diagram of the tooth failure modes provided in the embodiments of this application.

[0032] Figure 4 This is a schematic flowchart illustrating the specific implementation process of the testing method provided in the embodiments of this application.

[0033] Figure 5 This is a schematic diagram of the variation curves of the number of cycles with the bending stress at the tooth root under different ambient temperatures, provided in the embodiments of this application.

[0034] Figure 6 This is a schematic block diagram of the gear bending fatigue testing device provided in the embodiments of this application.

[0035] Figure 7 This is a structural block diagram of the gear bending fatigue testing device provided in the embodiments of this application. Detailed Implementation

[0036] The technical solutions of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0037] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0038] The term "comprising" in this document indicates the presence of the described feature, whole, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0039] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0040] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "at least one" means one or more, and "more" means two or more, unless otherwise explicitly specified.

[0041] When testing the bending fatigue life of gears, the pulse load applied to the gear teeth by the testing device is first determined based on the required tooth root bending stress. Then, the testing device is controlled to cyclically apply the pulse load to the teeth, and the number of pulse load cycles (i.e., bending fatigue life) at which tooth failure (e.g., tooth root fracture or tooth surface plastic deformation) is determined. This method is primarily for metal gears. Compared to metal gears, plastic gears exhibit higher sensitivity to temperature changes in their mechanical properties. That is, temperature variations affect the fatigue life of plastic gears, and temperature changes must be considered when testing the bending fatigue life of plastic gears.

[0042] However, during the application of pulsed loads to the gear teeth, excessively high pulse frequencies can cause the contact area between the gear tooth surface and the indenter to heat up, resulting in test results that do not reflect the set ambient temperature. For example, if the bending fatigue life of a gear needs to be tested at 23°C, the temperature at the contact point between the gear tooth surface and the indenter might reach 40°C due to the excessively high pulse frequency. In this case, the test result might be the bending fatigue life of the gear at 40°C, instead of the bending fatigue life at 23°C, leading to a significant error and affecting the accuracy of the test results.

[0043] In view of this, embodiments of this application provide a method for testing the bending fatigue of gears. During the application of a pulsed load to the gear teeth, the method determines whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold. If the temperature difference is less than the first threshold, a pulsed load is applied to the gear teeth until the teeth reach failure conditions. This method, by applying a pulsed load only when the temperature difference is less than the first threshold, avoids including test results from cases where the tooth surface temperature deviates significantly from the ambient temperature, reducing test errors caused by tooth surface heating and thus improving the accuracy of the test results.

[0044] The method provided in this application can be applied to plastic gears, as well as gears made of other materials that are easily affected by temperature.

[0045] The following combination Figure 1 This application describes a method for testing the bending fatigue of gears according to embodiments. For example... Figure 1 As shown, the test method may include steps 110 to 130.

[0046] Step 110: Determine the pulse load applied to the gear teeth by the test device based on the tooth root bending stress.

[0047] Specifically, different pulse loads applied to the gear teeth by the testing device may cause different root bending stresses on the teeth, and different root bending stresses may correspond to different bending fatigue lives.

[0048] In some embodiments, the tooth root bending stress to be tested can be set by the operator based on experience, or by the controller based on historical experience data by default, or by other methods. After determining the tooth root bending stress, the pulse load applied to the gear teeth by the testing device can be determined based on the tooth root bending stress. This application does not limit how the pulse load is determined based on the tooth root bending stress. For example, after determining the tooth root bending stress, the corresponding pulse load can be determined based on a pre-trained machine learning model. As another example, a mapping relationship between the tooth root bending stress and the pulse load can be established in advance, and after determining the tooth root bending stress, the corresponding pulse load can be determined using this mapping relationship.

[0049] In some embodiments, after determining the tooth root bending stress, the pulse load can be determined as follows: First, the tooth subjected to the pulse load can be considered as a cantilever beam, the critical section and the load application point can be determined, and a mechanical model of the tooth can be established. The critical section can be determined using the 30° tangent method. Figure 2 As shown, draw a tangent line at a 30° angle to the centerline of the gear tooth and tangent to the tooth root fillet. The critical section is the cross-section drawn parallel to the axis through the two points of tangency. The load application point can be the contact point between the indenter of the testing device and the tooth surface, such as... Figure 2 Point E is shown. Secondly, the following formula (1) can be obtained through the mechanical model of the gear teeth:

[0050]

[0051] The maximum value of the pulse load can be determined according to formula (1). In formula (1), F n Where b is the maximum value of the pulse load, and S is the tooth width of the gear. Fn σ is the tooth thickness at the critical section of the gear tooth. F For the bending stress at the tooth root, α Fen h is the load angle at the point of application of the load. Fe It is the bending lever arm at the point of application of the load.

[0052] Then, based on the basic parameters of the tested gear, the tooth thickness at the critical section, the load angle at the load application point, and the bending lever arm at the load application point are determined. The basic parameters of the gear are used to determine the dimensions of the teeth. For example, the basic parameters of a gear may include parameters related to the gear's dimensions such as the root circle diameter, common normal length, number of teeth spanned by the common normal, number of teeth, normal number of teeth, module, normal module, pressure angle tilt error, pressure angle tilt error evaluation length, pressure angle, normal pressure angle, root fillet radius, base circle diameter, displacement coefficient, and pitch circle radius.

[0053] The tooth thickness at the critical section can be determined by the following formula (2):

[0054]

[0055] In formula (2), Z is the number of teeth on the gear, m n ρ is the normal module of the gear. fp The radius of the tooth root fillet of the gear is denoted as .

[0056]

[0057] Z n h is the normal module of the gear. fp The root height of the gear teeth. The root height coefficient, d f Let m be the root circle diameter of the gear, m be the gear module, and x be the displacement coefficient. Let α be the length of the common normal to the gear, K be the number of teeth across which the common normal spans, and α be the length of the common normal. ′ This is the actual pressure angle of the gear. α is the theoretical design pressure angle of the gear, f Hαm L is the average value of the pressure angle tilt error. AE The length α is used to evaluate the pressure angle tilt error. n Let θ be the normal pressure angle of the gear. θ, G, and E have no specific physical meaning; they are only used for convenience.

[0058] The load angle at the point of application of the load can be determined by the following formula (3):

[0059] α Fen =α en -γ e (3)

[0060] In formula (3), α en The pressure angle at the point of application of the load. r is the pitch circle radius of the gear, d b Let d be the base circle diameter of the gear. en Let be the diameter of the circle containing the point of application of the load. γ e The tooth thickness half-angle at the point of load application.

[0061] The bending lever arm at the point of application of the load can be determined by the following formula (4):

[0062]

[0063] After determining the maximum value of the pulse load, the minimum value of the pulse load can be determined based on the maximum value. For example, the minimum value of the pulse load can be the product of the maximum value of the pulse load and the stress proportionality coefficient, i.e., F. m = n ·. Among them, F m R is the minimum value of the pulse load, and R is the stress proportionality factor. To ensure the stability of the testing process, in some embodiments, the stress proportionality factor can be set to 0.1. For example, if the maximum value of the pulse load is 50N and the stress proportionality factor is 0.1, then the minimum value of the pulse load is 5N.

[0064] Gears may have certain manufacturing errors, resulting in deviations between their actual basic parameters and the theoretical design parameters. By measuring the basic parameters (i.e., the actual basic parameters), determining the tooth thickness at the critical section, the load angle at the load application point, and the bending lever arm at the load application point, the pulse load can be more accurately determined, improving the accuracy of the test results.

[0065] Step 120: During the process of applying a pulse load to the gear teeth, determine whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold.

[0066] Step 130: If the temperature difference is less than the first threshold, continue to apply pulse load to the gear teeth until the gear teeth reach the failure condition.

[0067] The tooth surface temperature refers to the temperature at the point of application of the load on the tooth surface. For example, the tooth surface temperature can be detected using an infrared thermometer, a thermal imaging temperature measurement device, a laser temperature measurement device, or other temperature measurement methods. The ambient temperature is the average temperature of the space where the testing device is located, and can be set by the operator according to the testing requirements.

[0068] After detecting the tooth surface temperature, the temperature difference between the tooth surface temperature and the ambient temperature can be determined. If the temperature difference is less than a first threshold, a pulsed load is continued to be applied to the tooth until the tooth reaches the failure condition. The failure condition can be tooth root fracture, such as… Figure 3 The situation shown in (a) can also be caused by plastic deformation of the tooth surface, such as... Figure 3 (b) The situation described. Figure 3 As shown in (b), the dashed teeth in the dashed circle are the tooth surfaces of the teeth before the test, that is, the tooth surfaces of the teeth before they bear the pulse load, and the solid teeth at the corresponding positions are the tooth surfaces of the teeth after the test, that is, the tooth surfaces of the teeth after they bear the pulse load.

[0069] For example, when the deformation of the tooth surface (the displacement of the indenter under minimum pulse load) exceeds a set value, it can be considered that the tooth surface has undergone plastic deformation. Applying pulse load only when the temperature difference is less than a first threshold avoids including test results from cases where the tooth surface temperature deviates significantly from the ambient temperature, reducing test errors caused by tooth surface temperature rise and improving the accuracy of the test results.

[0070] Furthermore, in some embodiments, to improve testing efficiency, when the temperature difference is greater than or equal to a first threshold, the controller can adjust the first pulse frequency of the applied pulse load to a second pulse frequency, and when the temperature difference is less than the first threshold, control the testing device to continue applying the pulse load to the gear teeth at the second pulse frequency. The second pulse frequency is less than the first pulse frequency. During the application of the pulse load to the gear teeth, if the pulse frequency is set too high, the gear will heat up due to frequent bending deformation and elastic recovery; that is, the change in temperature difference may be due to the pulse frequency being set too high. By reducing the pulse frequency of the pulse load, the temperature difference can be made less than the first threshold, allowing the testing device to continue applying the pulse load to the gear teeth at the second pulse frequency. For example, during the application of the pulse load to the gear teeth at a pulse frequency of 10 Hz, if the temperature difference is greater than or equal to 5°C (the first threshold), then the pulse load is applied to the gear teeth at a pulse frequency of 8 Hz to make the temperature difference less than 5°C, and after the temperature difference is less than 5°C, the testing device continues to apply the pulse load to the gear teeth at a pulse frequency of 8 Hz.

[0071] In some embodiments, to improve testing efficiency, when the temperature difference is greater than or equal to a first threshold, the controller can also activate the cooling device to reduce the temperature difference to less than the first threshold, and then deactivate the cooling device after the temperature difference is less than the first threshold. The cooling device can be an air-cooled device, using cold air to cool the tooth surface temperature. Alternatively, it can be a water-cooled device, using cooling water to cool the tooth surface temperature. The cooling device can be a separate unit or part of the testing apparatus. For example, if the temperature difference is greater than or equal to 5°C (the first threshold), the controller activates the air-cooled device to deliver cold air to the tooth surface to lower its temperature. At this time, the controller can also stop applying pulse loads to the tooth surface. After the temperature difference is less than 5°C, the controller deactivates the air-cooled device and continues applying pulse loads to the tooth surface.

[0072] The gear bending fatigue testing method provided in this application first determines the pulse load applied to the gear teeth by the testing device based on the tooth root bending stress. Then, the determined pulse load is applied to the teeth, and during the application of the pulse load, it is determined whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold, i.e., whether the deviation between the tooth surface temperature and the ambient temperature is too large. If the temperature difference is less than the first threshold, the pulse load is continued to be applied to the teeth until the failure condition is reached. This method, by only continuing to apply the pulse load when the temperature difference is less than the first threshold, avoids test results including cases where the tooth surface temperature deviates significantly from the ambient temperature, reduces test errors caused by tooth surface temperature rise, and improves the accuracy of the test results.

[0073] The following combination Figure 4 The bending fatigue testing method for gears provided in the embodiments of this application is further described. For example... Figure 4 As shown, the test method may include steps 410 to 490.

[0074] Step 410: Determine the pulse load applied to the gear teeth by the test device based on the tooth root bending stress.

[0075] Specifically, steps 410 and 110 are the same, and will not be repeated here.

[0076] Step 420: Detect the surface temperature of the gear teeth.

[0077] For example, the tooth surface temperature can be detected by an infrared thermometer, a laser thermometer, or a thermal imaging device.

[0078] Step 430: Determine whether the temperature difference between the tooth surface temperature and the ambient temperature exceeds the first threshold.

[0079] During the process of applying a pulse load to the gear teeth, if the temperature difference exceeds (is greater than or equal to) the first threshold, step 440 is executed; if the temperature difference does not exceed the first threshold, step 450 is executed.

[0080] Step 440: Adjust the first pulse frequency to the second pulse frequency, or turn on the cooling device.

[0081] The second pulse frequency is lower than the first pulse frequency. The change in temperature difference may be due to the pulse frequency being set too high. In this case, appropriately reducing the pulse frequency or turning on the cooling device can quickly control the temperature difference below the first threshold, thereby executing step 450.

[0082] Step 450: Apply a pulse load to the gear teeth until the gear teeth reach the failure condition.

[0083] For example, if the temperature difference does not exceed a first threshold, a pulsed load is continuously applied to the gear teeth through a testing device until the tooth root fractures or the tooth surface undergoes plastic deformation. That is, until the gear teeth exhibit signs of fracture. Figure 3 The situation is shown below.

[0084] Step 460: Save the failure modes of the gear teeth under root bending stress and ambient temperature, and the number of pulse load cycles.

[0085] Specifically, different tooth root bending stresses may correspond to different failure modes and the number of pulse load cycles (i.e., the bending fatigue life of the gear), and different ambient temperatures may also correspond to different failure modes and the number of pulse load cycles. By storing the failure modes and the number of pulse load cycles of gear teeth under tooth root bending stress and ambient temperature, data support can be provided for gear use and material selection.

[0086] The failure modes can include tooth root fracture or plastic deformation of the tooth surface. For example, the tooth root bending stress is 60 MPa and the ambient temperature is 23°C. After tooth root fracture, the failure mode of the tooth at 60 MPa and 23°C is tooth root fracture, and the number of cycles at 60 MPa and 23°C is 50.

[0087] Step 470: Determine whether the number of pulse load cycles exceeds the second threshold.

[0088] If the number of pulse load cycles exceeds (is greater than or equal to) the second threshold, then step 480 is executed; if the number of pulse load cycles does not exceed the second threshold, then step 490 is executed. For example, the second threshold can be set to 10^7.

[0089] Step 480: Plot the curves showing the change in cycle number with tooth root bending stress under different ambient temperatures.

[0090] Before or during step 410, the operator can adjust the ambient temperature according to the test plan and record the number of pulse load cycles for the gear under different ambient temperatures. By plotting the curves showing the change in the number of cycles as a function of the tooth root bending stress at different ambient temperatures, the operator can more intuitively understand and analyze the gear's bending load-bearing capacity. The curves showing the change in the number of cycles as a function of the tooth root bending stress at different ambient temperatures can be shown as follows: Figure 5 As shown, the horizontal axis N represents the number of pulse load cycles, and the vertical axis S represents the tooth root bending stress.

[0091] Step 490: Update the tooth root bending stress.

[0092] The ability to store the number of cycles of the gear under different root bending stresses provides better data support for gear usage and material selection. After completing a test, i.e., after step 460, the root bending stress can be updated (modified) if the number of pulse load cycles is less than a second threshold. The updated root bending stress is used to determine the pulse load applied to the gear teeth under test by the testing device, thereby determining the failure mode and the number of pulse load cycles under the new root bending stress. If the number of pulse load cycles is greater than or equal to the second threshold, the root bending stress is not updated.

[0093] For example, an initial tooth root bending stress can be set according to testing requirements. After completing one test, the tooth root bending stress can be reduced by a certain percentage, and the pulse load applied to the new tooth (i.e., the tooth to be tested) in the gear by the testing device can be determined based on the reduced tooth root bending stress. This determines the number of pulse load cycles for the gear under different tooth root bending stresses. If the determined number of cycles is less than a second threshold, the tooth root bending stress is reduced again by a certain percentage; if the determined number of cycles is greater than or equal to the second threshold, the tooth root bending stress is not updated.

[0094] For example, according to the gear bending fatigue testing method provided in this embodiment, the tooth root bending stress can first be set to 65 MPa and the ambient temperature to 23°C. Then, the pulse load applied to the gear teeth by the testing device is determined based on the tooth root bending stress, and the tooth surface temperature is detected. If the temperature difference between the tooth surface temperature and the ambient temperature is less than a first threshold, the testing device is controlled to continuously apply the pulse load to the gear teeth in a cyclic manner until the tooth root fractures or the tooth surface undergoes plastic deformation. Afterwards, the failure mode of the gear at 65 MPa and 23°C and the number of pulse load cycles are saved, and if the number of cycles is less than a second threshold, the tooth root bending stress is updated to 60 MPa. Then, the pulse load applied to the new gear teeth by the testing device is determined based on the updated tooth root bending stress, and the tooth surface temperature is detected. If the temperature difference between the tooth surface temperature and the ambient temperature is less than the first threshold, the pulse load is repeatedly applied to the new gear teeth until the new gear root fractures or the tooth surface undergoes plastic deformation. Next, the failure modes and cycle counts of the pulsed load for the gear at 60 MPa and 23°C are recorded. If the cycle count is less than a second threshold, the root bending stress is updated to 55 MPa. This process is repeated until the cycle count exceeds the second threshold. Then, the ambient temperature can be set to 60°C and the root bending stress to 55 MPa. This process is repeated again until the cycle count exceeds the second threshold. By analogy, the failure modes and cycle counts of the pulsed load for the gear under different ambient temperatures and root bending stresses can be obtained. Finally, the following can also be obtained: Figure 5 The curves shown represent the change in the number of cycles of the gear under different ambient temperatures as a function of the bending stress at the tooth root.

[0095] In some embodiments, the tooth root bending stress can be updated directly after a test is completed. For example, a maximum and minimum value of the tooth root bending stress can be set according to test requirements. Then, the pulse load corresponding to the maximum value of the tooth root bending stress is first determined, and the number of pulse load cycles for the gear under the maximum value of the tooth root bending stress is determined. Afterward, the maximum value of the tooth root bending stress can be reduced by a certain proportion, and the pulse load corresponding to the reduced tooth root bending stress is determined, thereby determining the number of pulse load cycles for the gear under different tooth root bending stresses. The tooth root bending stress is stopped from being updated when the reduced tooth root bending stress is less than the minimum value.

[0096] To achieve the above embodiments, this application also provides a gear bending fatigue testing device. For example... Figure 6 As shown, the testing device 600 includes a determination module 610 and a processing module 620.

[0097] The determining module 610 is used to determine the pulse load applied to the gear teeth by the testing device 600 based on the tooth root bending stress. The determining module 610 is also used to determine whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold during the application of the pulse load to the gear teeth, where the tooth surface temperature is the temperature at the point of application of the load on the tooth surface. The processing module 620 is used to continue applying the pulse load to the gear teeth if the temperature difference is less than the first threshold until the gear teeth reach the failure condition. The failure condition includes: tooth root fracture or tooth surface plastic deformation.

[0098] Optionally, the processing module 620 is further configured to adjust the first pulse frequency of the applied pulse load to a second pulse frequency if the temperature difference is greater than or equal to a first threshold. The second pulse frequency is less than the first pulse frequency. Alternatively, if the temperature difference is greater than or equal to the first threshold, the cooling device is activated, and if the temperature difference is less than the first threshold, the cooling device is deactivated. The cooling device is used to reduce the tooth surface temperature.

[0099] Optionally, the determining module 610 is specifically used to determine the tooth thickness at the critical section, the load angle at the load application point, and the bending lever arm at the load application point based on the basic parameters of the detected gear. The basic parameters of the gear are used to determine the gear dimensions. Based on the tooth root bending stress, the tooth thickness at the critical section, the load angle at the load application point, the tooth width, and the bending lever arm at the load application point, the maximum value of the pulse load is determined using the following formula:

[0100]

[0101] Among them, F n Where b is the maximum value of the pulse load, and S is the tooth width of the gear. Fn σ is the tooth thickness at the critical section of the gear tooth. F For the bending stress at the tooth root, α Fen h is the load angle at the point of application of the load. Fe Let be the bending lever arm at the point of application of the load. The minimum value of the pulse load is determined based on the maximum value of the pulse load. The minimum value is the product of the maximum value and the stress proportionality coefficient.

[0102] Optionally, the testing device 600 also includes a storage module, which stores the failure mode and the number of pulse load cycles of the gear teeth under ambient temperature and tooth root bending stress after the teeth reach the failure condition. The failure modes include tooth root fracture or tooth surface plastic deformation.

[0103] Optionally, after the gear tooth reaches the failure condition, the processing module 620 is also used to update the tooth root bending stress, and the updated tooth root bending stress is used to determine the pulse load applied by the test device 600 to the gear tooth under test.

[0104] Optionally, the processing module 620 is specifically used to update the tooth root bending stress if the number of cycles of the pulse load is less than a second threshold.

[0105] Optionally, the basic parameters of the gear include: root circle diameter, common normal length, number of teeth spanned by the common normal, number of teeth, normal number of teeth, module, normal module, pressure angle tilt error, pressure angle tilt error evaluation length, pressure angle, normal pressure angle, root fillet radius, base circle diameter, displacement coefficient, and pitch circle radius.

[0106] This application also provides a gear bending fatigue testing device. For example... Figure 7 As shown, the testing device 700 includes a processor 710, a memory 720, and a communication interface 730. The memory 720 stores instructions, and the processor 710 executes these instructions. When an instruction is executed, the processor 710 performs the method provided in the above-described method embodiment. The processor 710 also controls the communication interface 730 to communicate with the outside world.

[0107] It should be understood that in the embodiments of this application, the processor can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0108] It should also be understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDR SDRAM), enhanced synchronous DRAM (ESDRAM), synchronous linked DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0109] This application also provides a computer-readable storage medium including a computer program that, when run on a computer, causes the computer to perform the methods provided in the above-described method embodiments.

[0110] This application also provides a chip system including a processor for calling and running a computer program from a memory, causing a device equipped with the chip system to perform the methods provided in the above-described method embodiments.

[0111] This application also provides a computer program product containing instructions that, when run on a computer, cause the computer to execute the method provided in the above-described method embodiments.

[0112] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0113] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0114] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0115] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0116] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0117] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0118] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for testing the bending fatigue of gears, characterized in that, include: The pulse load applied to the gear teeth by the test device is determined based on the tooth root bending stress. During the process of applying the pulse load to the gear teeth, it is determined whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold, wherein the tooth surface temperature is the temperature at the load application point on the tooth surface. If the temperature difference is less than the first threshold, the pulse load is continued to be applied to the tooth until the tooth reaches the failure condition, wherein the failure condition includes: tooth root fracture or tooth surface plastic deformation; The method further includes: If the temperature difference is greater than or equal to the first threshold, the first pulse frequency of the applied pulse load is adjusted to the second pulse frequency, wherein the second pulse frequency is less than the first pulse frequency.

2. The method according to claim 1, characterized in that, The determination of the pulse load applied to the gear teeth by the test device based on the tooth root bending stress includes: The tooth thickness at the critical section, the load angle at the load application point, and the bending lever arm at the load application point are determined based on the basic parameters of the gear detected. These basic parameters are used to determine the size of the gear. The maximum value of the pulse load is determined by the following formula based on the tooth root bending stress, the tooth thickness at the critical section, the load angle at the load application point, the tooth width, and the bending lever arm at the load application point: in, The maximum value of the pulse load. The tooth width of the gear teeth. The tooth thickness of the gear tooth at the critical section. The bending stress at the tooth root, The load angle at the point of application of the load. The bending lever arm at the point of application of the load; The minimum value of the pulse load is determined based on the maximum value of the pulse load, wherein the minimum value is the product of the maximum value and the stress proportionality coefficient.

3. The method according to claim 1 or 2, characterized in that, After the gear tooth reaches the failure condition, the method further includes: The failure mode of the gear under the ambient temperature and the tooth root bending stress and the number of cycles of the pulse load are stored, wherein the failure mode includes: tooth root fracture or tooth surface plastic deformation.

4. The method according to claim 1 or 2, characterized in that, After the gear tooth reaches the failure condition, the method further includes: The tooth root bending stress is updated, and the updated tooth root bending stress is used to determine the pulse load applied by the test device to the test tooth of the gear.

5. The method according to claim 4, characterized in that, The updating of the tooth root bending stress includes: If the number of cycles of the pulse load is less than the second threshold, then the tooth root bending stress is updated.

6. A gear bending fatigue testing device, characterized in that, include: The determination module is used to determine the pulse load applied to the gear teeth by the test device based on the tooth root bending stress; The determining module is further configured to determine, during the process of applying the pulse load to the gear tooth, whether the temperature difference between the tooth surface temperature and the ambient temperature is greater than or equal to a first threshold, wherein the tooth surface temperature is the temperature at the load application point on the tooth surface. The processing module is configured to continue applying the pulse load to the gear tooth if the temperature difference is less than the first threshold until the gear tooth reaches the failure condition, wherein the failure condition includes: tooth root fracture or tooth surface plastic deformation. The processing module is also used for: If the temperature difference is greater than or equal to the first threshold, the first pulse frequency of the applied pulse load is adjusted to the second pulse frequency, wherein the second pulse frequency is less than the first pulse frequency.

7. A fatigue testing device for gears, characterized in that, It includes at least one processor, the at least one processor being coupled to a memory, reading and executing instructions in the memory to implement the method as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when run on a computer, causes the computer to perform the method as described in any one of claims 1 to 5.

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