Method for evaluating gear oil film thickness

Abstract

The application provides a gear oil film thickness evaluation method for evaluating the oil film thickness between the tooth surfaces of two gears of a gear pair. The evaluation method comprises: establishing a tooth surface analysis model of the gear pair based on the tooth surface design of the gear pair. According to the tooth surface analysis model, a three-dimensional simulation model is established. The three-dimensional simulation model is analyzed to obtain the contact state of the gear pair under a preset load condition. According to the contact state of the gear pair under the preset load condition, the gear oil film thickness is obtained. According to the gear oil film thickness, the safety factor is obtained to determine the pitting risk of the gear pair. The above evaluation method can improve the accuracy of the oil film thickness evaluation.

Description

Technical Field

[0001] This invention relates to gear lubrication, and more particularly to a method for evaluating gear oil film thickness. Background Technology

[0002] A gear pair is a basic transmission mechanism consisting of two meshing gears that transmit motion and power through direct contact between their tooth surfaces. To ensure smooth and reliable gear operation, the gear tooth surfaces must be well lubricated. This requires maintaining an oil film between the two tooth surfaces to prevent wear damage caused by direct contact. The thickness of the gear oil film directly affects gear wear, efficiency, and lifespan, and is a crucial parameter for evaluating gear lubrication effectiveness. In practical applications, the oil film thickness must be maintained within a suitable range to achieve optimal lubrication. Gear oil film thickness is influenced by factors such as lubricant viscosity, gear geometry, tooth linear velocity, operating temperature, and load.

[0003] However, the oil film thickness between transmission gears is currently mainly obtained indirectly through numerical analysis and empirical formulas. For spur gear pairs that haven't undergone micro-modification, there is a certain degree of impact at the tooth tip and root. For bevel gear pairs, the meshing area is smaller at one end, and may deviate from the ideal meshing position due to machining parameters, resulting in the contact area of ​​the tooth surface not being completely in the middle. Therefore, calculating the oil film thickness at the midpoint of spur or bevel gear pairs using formulas has a significant error compared to the actual situation. Summary of the Invention

[0004] The purpose of this invention is to provide a method for evaluating gear oil film thickness, which can improve the accuracy of oil film thickness evaluation.

[0005] One aspect of the present invention provides a method for evaluating gear oil film thickness, used to evaluate the oil film thickness between the tooth surfaces of two gears in a gear pair; the evaluation method includes: establishing a tooth surface analysis model of the gear pair based on the tooth surface design; establishing a three-dimensional simulation model based on the tooth surface analysis model; analyzing the three-dimensional simulation model to obtain the gear pair contact state under a preset load condition; obtaining the gear oil film thickness based on the gear pair contact state under the preset load condition; and obtaining a safety factor based on the gear oil film thickness to determine the pitting risk of the gear pair.

[0006] In one embodiment, the gear pair includes a spur gear pair; the step of establishing a tooth surface analysis model of the gear pair based on the tooth surface design includes: obtaining the design parameters and micro-modification characteristics of the spur gear pair; and establishing a tooth surface analysis model of the gear pair based on the design parameters and micro-modification characteristics of the spur gear pair.

[0007] In one embodiment, the design parameters of the spur gear pair include a combination of one or more of the following: the number of teeth, the module, the pressure angle, and the tooth width of the spur gear.

[0008] In one embodiment, the gear pair includes a bevel gear pair; the step of establishing a tooth surface analysis model of the gear pair based on the tooth surface design includes: obtaining the design parameters and machining parameters of the bevel gear pair; and establishing a tooth surface analysis model of the gear pair based on the design parameters and machining parameters of the bevel gear pair.

[0009] In one embodiment, the design parameters of the bevel gear pair include a combination of one or more of the following: number of teeth, module, pressure angle, tooth width, and shaft intersection angle.

[0010] In one embodiment, the machining parameters of the bevel gear pair include the cutter inclination angle and / or the rolling ratio.

[0011] In one embodiment, establishing a three-dimensional simulation model based on the tooth surface analysis model includes: obtaining the relationship and error between the gear shaft, gear pair, bearing, and housing; and establishing a three-dimensional simulation model of the gear pair based on the tooth surface analysis model and the relationship and error between the gear shaft, gear pair, bearing, and housing.

[0012] In one embodiment, the error includes assembly error and / or machining error.

[0013] In one embodiment, the step of analyzing the three-dimensional simulation model to obtain the contact state of the gear pair under a preset load condition includes: acquiring the preset load condition; inputting the preset load condition into the three-dimensional simulation model to obtain the contact stress distribution and contact imprint distribution of the gear pair under the preset load condition.

[0014] In one embodiment, obtaining the gear oil film thickness based on the gear pair contact state under a preset load condition includes: acquiring lubricating oil parameters and gear parameters; and inputting the lubricating oil parameters and gear parameters into a three-dimensional simulation model of the gear pair based on the gear pair contact state under the preset load condition to obtain the gear oil film thickness distribution.

[0015] In one embodiment, the lubricating oil parameters include a combination of one or more of the lubricating oil's specific heat capacity, viscosity-pressure coefficient, kinematic viscosity, and density.

[0016] In one embodiment, the gear parameters include a combination of one or more of the following: material thermal conductivity, tooth surface temperature, tooth surface roughness, and gear linear velocity.

[0017] In one embodiment, the gear oil film thickness satisfies:

[0018]

[0019] Among them, hs h is the dimensionless gear oil film thickness. y R represents the oil film thickness (μm). a For tooth surface roughness (μm);

[0020] Oil film thickness meets the following requirements:

[0021]

[0022] Among them, G M This is a material parameter, directly proportional to the viscosity-pressure coefficient; U Y W is a velocity parameter, proportional to absolute viscosity. Y For load parameters; S Y This is a sliding parameter, related to the linear velocity of the gear.

[0023] In one embodiment, the step of obtaining a safety factor based on the gear oil film thickness and determining the pitting risk of the gear pair includes: obtaining an allowable oil film thickness; obtaining a safety factor based on the gear oil film thickness and the allowable oil film thickness; and determining the pitting risk of the gear pair based on the safety factor.

[0024] In one embodiment, the safety factor satisfies:

[0025]

[0026] Among them, S λ For the safety factor, h s,min λ represents the minimum dimensionless gear oil film thickness. GFP The allowable oil film thickness is dimensionless.

[0027] In one embodiment, determining the pitting risk of the gear pair based on a safety factor includes: if the safety factor is greater than 2, the pitting risk is determined to be low risk; if the safety factor is less than 1, the pitting risk is determined to be high risk; if the safety factor is greater than or equal to 1 and less than or equal to 2, the pitting risk is determined to be limited risk.

[0028] The gear oil film thickness evaluation method of the present invention is based on tooth surface design to establish a tooth surface analysis model, which fully considers the influence of the geometric shape of the tooth surface on the oil film thickness, improves the accuracy of the tooth surface analysis model, and makes the tooth surface analysis model and the actual gear pair test piece structurally highly consistent, thereby improving the accuracy of the three-dimensional simulation model and ensuring the reliability and accuracy of the oil film thickness results. Attached Figure Description

[0029] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0030] Figure 1This is a schematic flowchart of an embodiment of the gear oil film thickness evaluation method according to the present invention;

[0031] Figure 2 This is a schematic diagram of one embodiment of a spur gear pair;

[0032] Figure 3 This is a schematic diagram of one embodiment of a bevel gear pair;

[0033] Figure 4 This refers to the specific parameter settings of one embodiment of a bevel gear pair;

[0034] Figure 5 This is a schematic diagram of the contact state of a spur gear pair under a preset load condition.

[0035] Figure 6 This is a schematic diagram of the contact state of a bevel gear pair under a preset load condition.

[0036] Figure 7 This is a schematic diagram of the dimensionless gear oil film thickness of a spur gear pair;

[0037] Figure 8 This is a schematic diagram of the dimensionless gear oil film thickness of a bevel gear pair. Detailed Implementation

[0038] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the invention and not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the invention without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0039] As used herein, the term "gear pair" refers to a basic transmission mechanism consisting of two meshing gears that transmit motion and power through direct contact between their tooth surfaces. The term "oil film thickness" refers to the thickness of the lubricating oil film between the meshing tooth surfaces.

[0040] Figure 1 An embodiment of the gear oil film thickness evaluation method of the present invention is shown. The evaluation method of the present invention is used to evaluate the thickness of the lubricating oil film between the tooth surfaces of two gears in a gear pair. Figure 1 As shown, the evaluation method of the present invention includes steps S100 to S500:

[0041] In step S100, based on the tooth surface design of the gear pair, a tooth surface analysis model of the gear pair is established.

[0042] In step S200, a three-dimensional simulation model is established based on the tooth surface analysis model.

[0043] In step S300, the three-dimensional simulation model is analyzed to determine the contact state of the gear pair under the preset load conditions.

[0044] In step S400, the gear oil film thickness is obtained based on the gear pair contact state under a preset load condition.

[0045] In step S500, a safety factor is obtained based on the gear oil film thickness to determine the pitting risk of the gear pair. This step can determine the rationality of the oil film thickness, and thus determine whether structural optimization of the gear pair or optimization of lubricant parameters is needed to improve lubrication and make the oil film thickness more reasonable. Pitting risk refers to the possibility or probability that the gear tooth surface or subsurface will experience contact fatigue failure under alternating contact stress, forming localized spalling pits (pitting). In other words, it is the potential failure risk where the contact stress exceeds the material's contact fatigue limit, leading to surface material detachment and affecting the normal operation of the gear.

[0046] The gear oil film thickness evaluation method of the present invention is based on tooth surface design to establish a tooth surface analysis model, which fully considers the influence of the geometric shape of the tooth surface on the oil film thickness, improves the accuracy of the tooth surface analysis model, and makes the tooth surface analysis model and the actual gear pair test piece structurally highly consistent, thereby improving the accuracy of the three-dimensional simulation model and ensuring the reliability and accuracy of the oil film thickness results.

[0047] Gear pairs include spur gear pairs and bevel gear pairs. For example, Figure 2 As shown, a spur gear pair consists of two spur gears, which are mounted on a gear shaft, and bearings are used to support the gear shaft. Figure 3 As shown, the bevel gear pair consists of two bevel gears, which are mounted on a gear shaft. A bearing (not shown) is used to support the gear shaft.

[0048] The tooth surface design of spur gear pairs includes micro-modification, which refers to making minor local geometric modifications to the tooth surface (tooth profile or tooth direction) to improve the contact characteristics during gear meshing, reduce impact vibration, and minimize edge stress concentration, thereby improving transmission accuracy and lifespan. Spur gear pairs without micro-modification may experience tip-to-root contact, leading to a certain degree of tip-to-root impact. In related technologies, the oil film thickness at the midpoint of bevel gears is calculated using empirical formulas; however, for spur gear pairs without micro-modification, the calculated result has a significant error compared to the actual oil film thickness.

[0049] In one embodiment, step S100 further includes steps S110 to S120:

[0050] In step S110, the design parameters and micro-modification characteristics of the spur gear pair are obtained. The design parameters of the spur gear pair include a combination of one or more of the following: number of teeth, module, pressure angle, and tooth width. The micro-modification characteristics include whether the spur gear pair has undergone micro-modification or not.

[0051] In step S120, a tooth surface analysis model of the spur gear pair is established based on its design parameters and micro-modification characteristics. In this step, the spur gear pair design parameters can be input into T3D software to achieve accurate tooth surface modeling. Spur gear modification parameters can be directly manipulated in T3D software, while bevel gear parameters can be obtained based on GEMS or other relevant gear design software.

[0052] The tooth surface design of bevel gear pairs includes machining parameters, which involve multiple dimensions such as geometric design, machining equipment, cutting tools, and process specifications, directly affecting the gear's accuracy and meshing performance. Bevel gear pairs with different machining parameters may experience a smaller meshing area at one end, deviating from the ideal meshing position during actual operation, resulting in the contact area of ​​the tooth surface not being completely in the middle. In related technologies, the oil film thickness at the midpoint of the bevel gear is calculated using empirical formulas. However, for bevel gear pairs where the contact area is not completely in the middle of the tooth surface, the calculated result has a significant error compared to the actual oil film thickness.

[0053] In another embodiment, step S100 further includes steps S130 to S140:

[0054] In step S130, the design parameters and machining parameters of the bevel gear pair are obtained. The design parameters of the bevel gear pair include a combination of one or more of the following: number of teeth, module, pressure angle, tooth width, and shaft intersection angle. The machining parameters of the bevel gear pair include the cutter inclination angle and / or rolling ratio. Figure 4 A specific embodiment of the design parameters and machining parameter settings for a bevel gear pair is shown.

[0055] In step S140, a tooth surface analysis model of the bevel gear pair is established based on its design and machining parameters. In this step, the bevel gear pair design parameters obtained from GEMS or related gear design software can be input into T3D software to achieve accurate tooth surface modeling.

[0056] In one embodiment, step S200 further includes steps S210 to S220:

[0057] In step S210, the relationships and errors of the gear shaft, gear pair, bearing, and housing are obtained. These errors include assembly errors and / or machining errors. If measured values ​​are available, they can be input; otherwise, they can be preset based on the dimensional chain (i.e., the error design value).

[0058] In this step, the relationship between the gear shaft, gear pair, bearing, and housing can be understood as the connection between the gear shaft, gear pair, bearing, and housing, as well as the supporting role of the gear shaft, bearing, and housing for the gear pair.

[0059] In step S220, based on the tooth surface analysis model, and considering the relationships and errors between the gear shaft, spur gear pair, bearings, and casing, a three-dimensional simulation model of the gear pair is established, referencing... Figure 2 and Figure 3 As shown, a three-dimensional simulation model can be built in T3D software. The supporting role of the casing and bearings is generally represented in the form of a stiffness matrix to reduce computation time.

[0060] The three-dimensional simulation model established in step S220 is a full three-dimensional finite element model, which fully considers the influence of gear geometry, tooth linear velocity at different positions, and gear system load, resulting in high accuracy of calculation results. In contrast, related technologies evaluate oil film thickness based on maximum load and maximum pitch linear velocity, leading to larger calculation errors.

[0061] In one embodiment, step S300 further includes steps S310 to S320:

[0062] In step S310, a preset load condition is obtained. Here, unlike the maximum load, the preset load condition represents the load situation at various positions of the gear pair under a specified condition, which can be understood as the load distribution of the gear pair.

[0063] In step S320, the preset load conditions are input into the three-dimensional simulation model to obtain the contact stress distribution and contact imprint distribution of the gear pair under the preset load conditions, which provides input for the oil film thickness calculation in subsequent steps, that is, provides load parameters at various points on the tooth surface for the calculation of oil film thickness.

[0064] Figure 5 The contact state of one embodiment of a spur gear pair is shown. Figure 6 The contact state of one embodiment of a bevel gear pair is shown. Figure 5 In the diagram, different colors represent the stress conditions (i.e., stress magnitude) and contact areas at various contact points on the spur gear tooth surface, while the dashed box shows a magnified view of the local stress on the tooth surface. Figure 6 In the diagram, different colors represent the stress conditions and contact areas at various contact points of the bevel gear, and the block diagram shows a magnified view of the stress on the tooth surface.

[0065] In one embodiment, step S400 further includes steps S410 to S420:

[0066] In step S410, lubricating oil parameters and gear parameters are obtained. The lubricating oil parameters include a combination of one or more of the following: specific heat capacity, viscosity-pressure coefficient, kinematic viscosity, and density. The gear parameters include a combination of one or more of the following: material thermal conductivity, tooth surface temperature, tooth surface roughness, and gear linear velocity.

[0067] In step S420, based on the gear pair contact state under preset load conditions, the lubricating oil parameters and gear parameters are input into the three-dimensional simulation model of the gear pair to obtain the gear oil film thickness distribution.

[0068] The gear oil film thickness satisfies the relationship (1):

[0069]

[0070] In relation (1), h s h is the dimensionless gear oil film thickness, also known as the specific oil film thickness. y R represents the oil film thickness (μm). a Let R be the tooth surface roughness (μm). In the above formula, the tooth surface roughness R of the two gears is assumed to be... a If the roughness is the same, the average roughness or other roughness relationship can be used as the tooth surface roughness R in relationship (1). a .

[0071] Oil film thickness h y Satisfying relation (2):

[0072]

[0073] In relation (2), G M This is a material parameter, directly proportional to the viscosity-pressure coefficient. U Y This is a speed parameter, directly proportional to absolute viscosity, and strongly correlated with the properties of the lubricating oil. W Y This is a load parameter and is independent of the lubricating oil. S Y This is a sliding parameter, related to the gear linear velocity; for details, please refer to the ISO / TR 15144 standard.

[0074] The gear oil film thickness at different tooth surface positions can be obtained by calculating through steps S410 to S420 and relations (1) and (2), i.e. Figure 7 and Figure 8 The distribution of oil film thickness is shown. Among them, Figure 7 yes Figure 2 as well as Figure 5 The oil film thickness distribution of the spur gear pair shown; Figure 8yes Figure 3 as well as Figure 6 The oil film thickness distribution of the bevel gear pair is shown in the figure, where the structure of the bevel gear's tooth root, tooth tip, large end, and small end is illustrated. Figure 7 In the middle, the colored part is greater than the oil film thickness h. s In the 0-0.2 range, please refer to the legend for details. From Figure 7 The specific oil film thickness h at the tooth tip position is visible in the middle. s Minimum. Figure 8 The colored portion is greater than the oil film thickness h. s In the 0-0.5 range, from Figure 8 The minimum specific oil film thickness h of the visible blue portion s It is 0.23.

[0075] Continue to refer to Figure 7 and Figure 8 Among the gear oil film thicknesses at multiple different locations, there exists a dimensionless minimum value h for the gear oil film thickness. s,min In one specific embodiment, the minimum value h of the dimensionless gear oil film thickness of the spur gear pair s,min It is 0.075, such as Figure 7 As shown. In another specific embodiment, the minimum value h of the dimensionless gear oil film thickness of the bevel gear pair. s,min It is 0.23, such as Figure 8 As shown. Compared to the oil film thickness at the midpoint obtained by empirical formulas in related technologies, the oil film thickness distribution calculated by this invention can clearly identify areas with high risk of pitting on the tooth surface. This can be optimized through local tooth surface modification or enhanced lubrication, including but not limited to removing high points before leaving the factory. The oil film thickness distribution at different locations on the tooth surface can provide a clear direction for improving gear lubrication performance and optimizing tooth surface design.

[0076] In one embodiment, step S500 further includes steps S510 to S530:

[0077] In step S510, the allowable oil film thickness is obtained. The allowable oil film thickness is an empirical value, related to parameters such as gear material, heat treatment method, load torque, and the viscosity and density of the lubricating oil. It can be obtained by looking up a table or other methods, and this invention does not impose any limitations on it.

[0078] In step S520, the safety factor is obtained based on the gear oil film thickness and the allowable oil film thickness.

[0079] In step S530, the pitting risk of the gear pair is determined based on a safety factor. The safety factor is used to assess the reasonableness of the oil film thickness and provides a reference for engineering tests.

[0080] Specifically, the safety factor satisfies the relationship (3):

[0081]

[0082] In relation (3), S λ For the safety factor, h s,min λ represents the minimum dimensionless gear oil film thickness. GFP Let h be the dimensionless allowable oil film thickness. The minimum dimensionless gear oil film thickness is h. s,min It is possible Figure 7 and Figure 8 get.

[0083] Furthermore, step S530 includes steps S531 to S533 to determine the pitting risk using a safety factor:

[0084] In step S531, if the safety factor is greater than 2, the pitting risk is determined to be low and the gear oil film thickness is determined to be reasonable.

[0085] In step S532, if the safety factor is less than 1, the pitting risk is determined to be high, and the gear oil film thickness is determined to be unreasonable. Steps S100 to S500 can be repeated to optimize the structure of the gear pair to improve lubrication.

[0086] In step S533, if the safety factor is greater than or equal to 1 and less than or equal to 2, the pitting risk is determined to be a limited risk, and the gear oil film thickness needs to be further evaluated in combination with factors such as operating time.

[0087] In one specific embodiment, the dimensionless allowable oil film thickness λ is determined based on the contact pressure and the number of lifetime cycles. GFP Let's take it as 0.07. Then we can obtain the safety factor S for the spur gear pair. λ The safety factor S for the bevel gear pair is 1.07, indicating a certain risk of pitting corrosion. However, considering that this is a low-oil operating condition with a very short actual operating time, the risk of pitting corrosion is acceptable. λ The value is 3.29, indicating a low risk of pitting corrosion.

[0088] The gear oil film thickness evaluation method of the present invention establishes an accurate tooth surface model of the gear pair, ensuring that the contact state of the bevel gear is consistent with the actual working state, ensuring the effectiveness of the gear oil film thickness calculation method in the bevel gear system, improving the accuracy of the bevel gear tooth surface oil film thickness calculation results, and solving the problem in engineering where the tooth surface of bevel gears cannot be accurately modeled due to the influence of machining parameters, resulting in the inability to evaluate the tooth surface oil film thickness or a large evaluation error.

[0089] The evaluation method of this invention is based on a full three-dimensional finite element model for analysis, which fully considers the influence of gear geometry, tooth linear velocity at different positions, and gear system load. At the same time, the viscosity of lubricating oil, operating temperature, tooth surface roughness, and load are used as inputs to the model, simulating its real working state with high fidelity. The analysis results are reliable and the calculation results are highly accurate. It solves the problem of large calculation errors when evaluating based on maximum load and maximum pitch linear velocity in engineering, and has strong engineering applicability.

[0090] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for evaluating gear oil film thickness, used to evaluate the oil film thickness between the tooth surfaces of two gears in a gear pair; Its features are, The evaluation method includes: Based on the tooth surface design of the gear pair, an analytical model of the tooth surface of the gear pair is established; Based on the tooth surface analysis model, a three-dimensional simulation model is established; The three-dimensional simulation model was analyzed to obtain the contact state of the gear pair under the preset load conditions; The gear oil film thickness is obtained based on the gear pair contact state under preset load conditions; Based on the gear oil film thickness, a safety factor is obtained, and the pitting risk of the gear pair is determined.

2. The evaluation method as described in claim 1, characterized in that, The gear pair includes a spur gear pair; The gear pair tooth surface design, including the establishment of a tooth surface analysis model for the gear pair, comprises: Obtain the design parameters and micro-modification characteristics of spur gear pairs; Based on the design parameters and micro-modification characteristics of the spur gear pair, a tooth surface analysis model for the gear pair is established.

3. The evaluation method as described in claim 1, characterized in that, The design parameters of a spur gear pair include a combination of one or more of the following: number of teeth, module, pressure angle, and tooth width.

4. The evaluation method as described in claim 1, characterized in that, The gear pair includes a bevel gear pair; The gear pair tooth surface design, including the establishment of a tooth surface analysis model for the gear pair, comprises: Obtain the design and machining parameters of the bevel gear pair; Based on the design and machining parameters of the bevel gear pair, a tooth surface analysis model of the gear pair is established.

5. The evaluation method as described in claim 4, characterized in that, The design parameters of the bevel gear pair include a combination of one or more of the following: number of teeth, module, pressure angle, tooth width, and shaft intersection angle.

6. The evaluation method as described in claim 4, characterized in that, The machining parameters of the bevel gear pair include the cutter inclination angle and / or rolling ratio.

7. The evaluation method according to any one of claims 1-6, characterized in that, The process of establishing a three-dimensional simulation model based on the tooth surface analysis model includes: Obtain the relationship and error between the gear shaft, gear pair, bearing and housing; Based on the tooth surface analysis model, and considering the relationship and errors of the gear shaft, gear pair, bearing, and casing, a three-dimensional simulation model of the gear pair is established.

8. The evaluation method as described in claim 7, characterized in that, The errors include assembly errors and / or machining errors.

9. The evaluation method as described in claim 7, characterized in that, The analysis of the three-dimensional simulation model to obtain the contact state of the gear pair under the preset load conditions includes: Obtain the preset load conditions; By inputting the preset load conditions into the three-dimensional simulation model, the contact stress distribution and contact imprint distribution of the gear pair under the preset load conditions are obtained.

10. The evaluation method as described in claim 9, characterized in that, The process of obtaining the gear oil film thickness based on the gear pair contact state under a preset load condition includes: Obtain lubricating oil parameters and gear parameters; Based on the gear pair contact state under preset load conditions, the lubricating oil parameters and gear parameters are input into the three-dimensional simulation model of the gear pair to obtain the gear oil film thickness distribution.

11. The evaluation method as described in claim 10, characterized in that, The lubricating oil parameters include a combination of one or more of the following: specific heat capacity, viscosity-pressure coefficient, kinematic viscosity, and density.

12. The evaluation method as described in claim 11, characterized in that, The gear parameters include a combination of one or more of the following: material thermal conductivity, tooth surface temperature, tooth surface roughness, and gear linear velocity.

13. The evaluation method as described in claim 12, characterized in that, The gear oil film thickness meets the following requirements: Among them, h s h is the dimensionless gear oil film thickness. y R represents the oil film thickness (μm). a For tooth surface roughness (μm); Oil film thickness meets the following requirements: Among them, G M This is a material parameter, directly proportional to the viscosity-pressure coefficient; U Y W is a velocity parameter, proportional to absolute viscosity. Y For load parameters; S Y This is a sliding parameter, related to the linear velocity of the gear.

14. The evaluation method according to any one of claims 1-6, characterized in that, The process of determining the pitting risk of the gear pair by obtaining a safety factor based on the gear oil film thickness includes: Obtain the allowable oil film thickness; The safety factor is obtained based on the gear oil film thickness and the allowable oil film thickness; The pitting risk of this gear pair is determined based on the safety factor.

15. The evaluation method as described in claim 14, characterized in that, The safety factor satisfies: Among them, S λ For the safety factor, h s,min λ represents the minimum dimensionless gear oil film thickness. GFP The allowable oil film thickness is dimensionless.

16. The evaluation method as described in claim 15, characterized in that, The determination of the pitting risk of the gear pair based on the safety factor includes: If the safety factor is greater than 2, then the pitting risk is determined to be low. If the safety factor is less than 1, then the pitting risk is determined to be high. If the safety factor is greater than or equal to 1 and less than or equal to 2, then the pitting risk is determined to be a finite risk.

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