An aero spiral bevel gear modification method based on simulation

Abstract

The present application belongs to the technical field of structural strength simulation, and particularly relates to a kind of aviation spiral bevel gear modification methods based on simulation. In addition to establishing the transmission system component model containing spiral bevel gear, gear shaft, bearing, bearing seat, gear box and other structures in simulation, an additional mandrel corresponding to the inner hole of the gear shaft is established, and vibration output simulation nodes are established at the center points of the gear box and the mandrel, which are used to extract vibration data such as gear shaft displacement, speed and acceleration. After simulation, the gear modification scheme is adjusted according to the gear stress and vibration, until the gear contact and system vibration requirements are met. This method not only allows you to view the gear contact stress, but also allows you to view key parameters such as displacement, speed, acceleration and other related parameters of gear shaft and gear box vibration. The aviation spiral bevel gear modification using this method can effectively improve the feasibility of the modification scheme.

Description

Technical Field

[0001] This invention belongs to the field of structural strength simulation technology, specifically relating to a simulation-based method for modifying aerospace spiral bevel gears. Background Technology

[0002] Spiral bevel gears are crucial components of aero-engine accessory transmission systems, transmitting power to aero-engine accessories. To ensure stable transmission system operation, the spiral bevel gears require a reasonable tooth profile and tooth contour to prevent excessive transmission errors and meshing impacts during engagement, which could lead to abnormal gear contact, pitting, breakage, or excessive system vibration. To guarantee stable transmission system operation, the spiral bevel gears often need to be modified. Currently, common simulation-based spiral bevel gear modification methods include two types: static modification and modification. Static modification involves applying a static transmission load without considering gear meshing, obtaining the contact imprint morphology, and then modifying the gear to adjust contact stress and contact position. The second method uses general-purpose finite element simulation software such as ANSYS to analyze the dynamic meshing of the gears using static analysis, obtaining contact stress and contact imprints, and then modifying the gear to reduce contact stress and improve the contact imprint.

[0003] The main problem with the two modification methods mentioned above is that they only analyze the static or simulated dynamic contact state of the gears. The modification work can only meet the needs of reducing contact stress or adjusting contact marks. They cannot identify the impact of the modified gear on the system vibration. The resulting gear structure cannot meet the need to reduce system vibration, and may even increase system vibration, leading to other forms of failure or damage to the system. Summary of the Invention

[0004] Purpose of the invention: To provide a simulation-based method for modifying aerospace spiral bevel gears, which can meet the requirements of contact stress and contact imprint, as well as the requirement of reducing system vibration, thereby improving the reliability of the modified gears and enhancing the stability of the transmission system.

[0005] Technical solution:

[0006] A simulation-based method for modifying aero-helical bevel gears includes:

[0007] Step 1: Create a 3D digital model of all parts included in the transmission system assembly except for the spiral bevel gear, including the gear shaft, bearing, bearing housing, and gearbox.

[0008] Step 2: Establish a three-dimensional digital model of the mandrel corresponding to the center hole of the gear shaft. The size of the mandrel is consistent with the size of the center through hole of the gear shaft of the spiral bevel gear.

[0009] Step 3: Create a 3D digital model of the spiral bevel gear including all parameters;

[0010] Step 4: Assemble the 3D model of the spiral bevel gear with the models of the gear shaft, spindle, bearing, bearing housing, and gearbox to form a 3D model of the simulation analysis component;

[0011] Step 5: Import the 3D digital model of the simulation analysis component into transient simulation analysis software that can perform dynamic operation simulation of the gear transmission system;

[0012] Step 6: Perform finite element mesh generation on the simulation analysis components;

[0013] Step 7: Establish one-to-one coupling relationships between the nodes on the outer surface of the spindle and the nodes on the inner surface of the gear shaft, as well as between the outer surface of the bearing outer ring and the inner surface of the bearing housing, the outer surface of the bearing housing and the inner surface of the gearbox mounting hole, and the inner surface of the bearing inner ring and the nodes on the outer surface of the gear shaft.

[0014] Step 8: Establish material parameters based on the design materials of the parts, and assign corresponding material parameters to each part, which are spiral bevel gears, bearings, bearing housings, gearboxes, and gear shafts;

[0015] Step 9: Establish and assign mandrel material parameters;

[0016] Step 10: Establish the contact relationships of all gear pairs within the gearbox;

[0017] Step 11: Establish bearing contact relationships;

[0018] Step 12: Establish bolt connection relationships or bolt hole coupling relationships, and apply fixed constraints to the bolt hole coupling points at the gearbox mounting location;

[0019] Step 13: Establish a speed loading curve and a torque loading curve to ensure that the speed increases from zero until the operating speed is reached after the torque loading is completed.

[0020] Step 14: Apply a speed loading curve to the input gear shaft and a torque loading curve to the output gear shaft;

[0021] Step 15: Establish and apply the system damping curve; the damping should be maintained at 20 before the speed load is completed, and the damping should be reduced to below 5 after the speed load is completed;

[0022] Step 16: Establish simulation nodes for spindle vibration output and gearbox vibration output;

[0023] Step 17: Set the solution parameters, including but not limited to total time and time step;

[0024] Step 18: Calculate the stress, contact state, displacement, velocity, and acceleration of the gear transmission system based on steps 1 to 17.

[0025] Step 19: Check the stress changes and contact state changes during gear meshing, specifically including: whether there is abnormal contact at the tooth tip or tooth root, whether there is off-center loading, and whether there is excessive stress.

[0026] Step 20: Extract the displacement, velocity, and acceleration changes of the spindle vibration output simulation node and the gearbox vibration output simulation node during gear meshing;

[0027] Step 21: Evaluate the gear stress and vibration of the gear shaft and gearbox, specifically including: a) whether the contact stress meets the standard; b) whether the vibration value meets the requirements; c) whether there is edge contact.

[0028] Step 22: Modify the spiral bevel gear; specifically including: modifying the tooth tip fillet and tooth root fillet for excessive stress or vibration caused by abnormal contact between the tooth tip and tooth root; modifying the gear with a drum shape for excessive stress caused by edge contact; modifying the gear with a drum shape for excessive stress and vibration caused by excessive normal contact stress; and modifying the gear with a drum shape under off-center load conditions.

[0029] Step 23: Repeat steps 3 to 22 until the gear meshing stress and the vibration of the gear shaft and gearbox all meet the design requirements.

[0030] Furthermore, step six specifically includes: using tetrahedral meshes for the gearbox body and hexahedral meshes for other parts to ensure analysis accuracy.

[0031] Furthermore, step nine specifically includes: its density is not greater than 1 g / cm³. 3 Its elastic modulus is not greater than 2000MPa.

[0032] Further, step ten specifically includes: the contact method is symmetrical contact, the static friction coefficient is not greater than 0.15, the dynamic friction coefficient is not greater than 0.1, the initial contact state is adjusted, the initial gap and initial penetration are eliminated, and the gear pair is ensured to make just the right contact.

[0033] Further, step eleven specifically includes: using a convex-concave fit to simulate the contact relationship of a ball bearing, and using an inner and outer ring fit to simulate the contact relationship of a roller bearing; the convex-concave fit simulation simplifies the inner ring and roller of the ball bearing into a ring with a convex cross-section, and simplifies the outer ring of the bearing into another ring with a concave cross-section, with the gap between the two rings controlled according to the bearing clearance; the inner and outer ring fit simulation simplifies the roller bearing into two inner and outer rings, both with rectangular cross-sections, with the gap between them controlled according to the bearing clearance.

[0034] Furthermore, step 12 specifically includes: if bolts need to be established, coupling the bolt outer surface node to the bolt hole inner surface node one-to-one; if bolt hole coupling needs to be established, coupling the two bolt hole inner surface nodes that need to be connected into one node.

[0035] Further, step fourteen specifically includes: firstly, establishing a first rigid body planar element at the input end of the input gear shaft, the first rigid body planar element needing to be coupled one-to-one with the solid node of the input gear shaft, and applying a speed loading curve to the first rigid body planar element; secondly, establishing a second rigid body planar element at the output end of the output gear shaft, the second rigid body planar element needing to be coupled one-to-one with the solid node of the output gear shaft, and applying a torque loading curve to the second rigid body planar element.

[0036] Further, step sixteen specifically includes: establishing vibration output simulation nodes at the center points on both sides of the spindle, and establishing gearbox vibration output simulation nodes at the gearbox test vibration measurement points.

[0037] Beneficial effects:

[0038] The present invention provides a simulation-based method for modifying aviation spiral bevel gears. This method can simulate the actual operating effect of the transmission system after modification of aviation spiral bevel gears. In addition to viewing the contact stress and contact state of the spiral bevel gears, the analysis results can also view key parameters such as displacement, velocity, and acceleration related to the vibration of the gear shaft and gearbox. The modification of aviation spiral bevel gears using this method can effectively improve the feasibility of the modification scheme and effectively improve the reliability of the modified gears. Attached Figure Description

[0039] Figure 1 This is a flowchart illustrating a simulation-based method for modifying aerospace spiral bevel gears, as provided by the present invention. Detailed Implementation

[0040] This invention discloses a simulation-based method for modifying aerospace spiral bevel gears. In addition to establishing a transmission system component model encompassing the spiral bevel gear, gear shaft, bearings, bearing housings, and gearbox, the simulation also includes a mandrel corresponding to the inner bore of the gear shaft. Vibration output simulation nodes are established at the center points of the gearbox and the mandrel to extract vibration data such as gear shaft displacement, velocity, and acceleration. After simulation, the gear modification scheme is adjusted based on gear stress and vibration conditions until the gear contact and system vibration requirements are met. This method not only allows for viewing gear contact stress but also key parameters related to gear shaft and gearbox vibration, such as displacement, velocity, and acceleration. Aerospace spiral bevel gear modification using this method effectively improves the feasibility of modification schemes.

[0041] The mandrel is perfectly matched to the gear shaft hole, and all nodes on the outer surface of the mandrel correspond one-to-one with all nodes on the inner surface of the gear shaft hole. Using this method, the vibration characteristics of the gear shaft's center point can be extracted, providing a direct visual display of the gear shaft's vibration during transmission system operation.

[0042] The elastic modulus of the mandrel material was set to approximately 2000 MPa, and the material density was set to approximately 1 g / cm³. 3 This parameter minimizes the impact of the mandrel on the gear shaft stiffness while ensuring the calculation is completed. Material parameters exceeding the above values ​​will cause a significant increase in gear shaft stiffness, resulting in a noticeable deviation from the actual stiffness and causing calculation errors; parameters below the above values ​​may prevent the calculation from being performed.

[0043] Vibration output simulation nodes are established at the center points of both ends of the mandrel to extract the vibration values ​​of the gear shaft. These simulation nodes allow for a direct view of the gear shaft's displacement, velocity, acceleration, and other vibration characteristics, which can be used to determine the operating status of aerospace spiral bevel gears.

[0044] A vibration output simulation node is established at the test measurement point of the gearbox to extract the vibration values ​​of the gearbox housing. This simulation node allows for a direct view of the vibration characteristics of the gear shaft, such as displacement, velocity, and acceleration, and can be used to determine the operating status of the gear transmission system.

[0045] A coupling point is established at the mounting hole of the gearbox housing, and a fixed constraint is applied to the coupling point. This method can effectively simulate the gearbox mounting method and improve computational efficiency.

[0046] During loading, a torque load is applied first, and then a rotational load is applied after the torque load has stabilized. This method can effectively reduce system vibration caused by loading, accelerate analysis convergence speed, accelerate simulation system stabilization, and improve analysis efficiency.

[0047] The initial system damping is set to around 20, and after the rotational load is applied, the damping drops below 5. This method can effectively reduce system vibration caused by loading, accelerate the analysis convergence speed, accelerate the stabilization of the simulation system, and improve analysis efficiency.

[0048] A calculation result output curve is established, using large step sizes for output before the system stabilizes and small step sizes for output after system stability. This controls the output density. This method can control the output density, save computer resources, and improve analysis efficiency.

[0049] like Figure 1 The present invention provides a simulation-based method for modifying aerospace spiral bevel gears, the specific steps of which include:

[0050] Step 1: Create a 3D digital model of all parts included in the transmission system assembly except for the spiral bevel gear, including the gear shaft, bearing, bearing housing, and gearbox.

[0051] Step 2: Establish a three-dimensional digital model of the mandrel corresponding to the center hole of the gear shaft. The size of the mandrel is consistent with the size of the center through hole of the gear shaft of the spiral bevel gear.

[0052] Step 3: Create a 3D digital model of the spiral bevel gear including all parameters;

[0053] Step 4: Assemble the 3D model of the spiral bevel gear with the models of the gear shaft, spindle, bearing, bearing housing, and gearbox to form a 3D model of the simulation analysis component;

[0054] Step 5: Import the 3D digital model of the simulation analysis component into transient simulation analysis software that can perform dynamic operation simulation of the gear transmission system;

[0055] Step 6: Perform finite element mesh generation on the simulation analysis components; specifically, the gearbox body is meshed using tetrahedral meshes, while other parts are meshed using hexahedral meshes to ensure analysis accuracy;

[0056] Step 7: Establish one-to-one coupling relationships between the nodes on the outer surface of the spindle and the nodes on the inner surface of the gear shaft, as well as between the outer surface of the bearing outer ring and the inner surface of the bearing housing, the outer surface of the bearing housing and the inner surface of the gearbox mounting hole, and the inner surface of the bearing inner ring and the nodes on the outer surface of the gear shaft.

[0057] Step 8: Establish material parameters based on the design materials of the parts, and assign corresponding material parameters to each part, which are spiral bevel gears, bearings, bearing housings, gearboxes, and gear shafts;

[0058] Step 9: Establish and assign mandrel material parameters, with a density not exceeding 1 g / cm³. 3 Its elastic modulus is not greater than 2000 MPa;

[0059] Step 10: Establish the contact relationship of all gear pairs in the gearbox; specifically, the contact method is symmetrical contact, the static friction coefficient is not greater than 0.15, the dynamic friction coefficient is not greater than 0.1, adjust the initial contact state, eliminate the initial gap and initial penetration, and ensure that the gear pairs are in just contact.

[0060] Step 11: Establish bearing contact relationships; specifically including: using a convex-concave fit to simulate the contact relationship of a ball bearing, and using an inner and outer ring fit to simulate the contact relationship of a roller bearing; the convex-concave fit simulation simplifies the inner ring and roller of the ball bearing into a ring with a convex cross-section, and simplifies the outer ring of the bearing into another ring with a concave cross-section, with the gap between the two rings controlled according to the bearing clearance; the inner and outer ring fit simulation simplifies the roller bearing into two inner and outer rings, both with rectangular cross-sections, with the gap controlled according to the bearing clearance.

[0061] Step 12: Establish bolt connection relationships or bolt hole coupling relationships, and apply fixed constraints to the bolt hole coupling points at the gearbox mounting location; if bolts are required, couple the outer surface nodes of the bolts to the inner surface nodes of the bolt holes one-to-one; if bolt hole coupling is required, couple the inner surface nodes of the two bolt holes that need to be connected into one node.

[0062] Step 13: Establish a speed loading curve and a torque loading curve to ensure that the speed increases from zero until the operating speed is reached after the torque loading is completed.

[0063] Step Fourteen: Apply a speed loading curve to the gear shaft of the input gear and a torque loading curve to the gear shaft of the output gear. Specifically, this includes: First, establishing a first rigid body planar element at the input end of the gear shaft of the input gear. The first rigid body planar element needs to be coupled one-to-one with the solid node of the gear shaft of the input gear. Apply a speed loading curve to the first rigid body planar element. Then, establish a second rigid body planar element at the output end of the gear shaft of the output gear. The second rigid body planar element needs to be coupled one-to-one with the solid node of the gear shaft of the output gear. Apply a torque loading curve to the second rigid body planar element.

[0064] Step 15: Establish and apply the system damping curve; the damping should be maintained at 20 before the speed load is completed, and the damping should be reduced to below 5 after the speed load is completed;

[0065] Step 16: Establish simulation nodes for mandrel vibration output and gearbox vibration output; specifically, this includes: establishing vibration output simulation nodes at the center points on both sides of the mandrel, and establishing gearbox vibration output simulation nodes at the vibration measurement points of the gearbox test.

[0066] Step 17: Set the solution parameters, including but not limited to total time and time step;

[0067] Step 18: Calculate the stress, contact state, displacement, velocity, and acceleration of the gear transmission system based on steps 1 to 17.

[0068] Step 19: Check the stress and contact state changes during gear meshing, specifically including: whether there is abnormal contact at the tooth tip or tooth root, whether there is excessive stress, and whether there is off-center loading.

[0069] Step 20: Extract the displacement, velocity, and acceleration changes of the spindle vibration output simulation node and the gearbox vibration output simulation node during gear meshing;

[0070] Step 21: Evaluate the gear stress and vibration of the gear shaft and gearbox, specifically including: a) whether the contact stress meets the standard; b) whether the vibration value meets the requirements; c) whether there is edge contact.

[0071] Step 22: Modify the spiral bevel gear; specifically including: modifying the tooth tip fillet and tooth root fillet for excessive stress or vibration caused by abnormal contact between the tooth tip and tooth root; modifying the gear with a drum shape for excessive stress caused by edge contact; modifying the gear with a drum shape for excessive stress and vibration caused by excessive normal contact stress; and modifying the gear with a drum shape under off-center load conditions.

[0072] Step 23: Repeat steps 3 to 22 until the gear meshing stress and the vibration of the gear shaft and gearbox all meet the design requirements.

[0073] Example:

[0074] Step 1: Use UG software or other 3D modeling software to create 3D digital models of all parts included in the transmission system components except for the spiral bevel gear, such as gear shafts, bearings, bearing housings, gearboxes, etc.

[0075] Step 2: Use UG software or other 3D modeling software to create a 3D digital model of the mandrel corresponding to the center hole of the gear shaft, which must exactly fill the center hole of the gear shaft;

[0076] Step 3: Use KIMoS software or other spiral bevel gear modeling software to create a 3D digital model of the aerospace spiral bevel gear including all parameters, and export it as .igs format or other common intermediate format;

[0077] Step 4: Use UG software or other 3D modeling software to assemble the 3D model of the spiral bevel gear with other structural models such as gear shaft, spindle, bearing, bearing housing, and gearbox to form a 3D model of the simulation analysis component, and export it as .igs format or other common intermediate format;

[0078] Step 5: Import the 3D digital model of the component into the transient simulation analysis software. The transient simulation analysis software can be LS-Dyna or other general transient dynamics analysis software.

[0079] Step 6: Perform finite element mesh generation on the component. The generated mesh must meet the finite element mesh generation standards, which can be as follows: a) The number of meshes in the tooth profile direction needs to meet the surface roughness requirements of the gear. Generally, the number of meshes in the tooth profile direction should be more than 13, and at the tooth root, there should be more than six meshes; b) The aspect ratio of the surface mesh should be less than 3, the skew angle should be less than 45°, and the Jacobian should be less than 0.7; c) The maximum to minimum side length ratio of the volume mesh should be less than 8, the mesh skew rate should be less than 0.5, and the Jacobian should be less than 0.7.

[0080] Step 7: Establish a one-to-one coupling relationship between the nodes on the outer surface of the mandrel and the nodes on the inner surface of the gear shaft;

[0081] Step 8: Establish material parameters based on the part design materials, and assign corresponding material parameters to each part. The material parameters include, but are not limited to, density, elastic modulus, and Poisson's ratio.

[0082] Step 9: Establish and assign mandrel material parameters, with a density not exceeding 1 g / cm³. 3 Its elastic modulus is not greater than 2000 MPa;

[0083] Step 10: A symmetrical contact relationship can be established between the gear pairs, with a static friction coefficient of no more than 0.15 and a dynamic friction coefficient of no more than 0.1, to eliminate the initial gap or penetration between the gear pairs and keep them in a just-contact state.

[0084] Step 11: The contact relationship of a ball bearing can be simulated by using a convex-concave fit, and the contact relationship of a roller bearing can be simulated by using an inner and outer ring fit.

[0085] Step 12: Bolt connection relationships or bolt hole coupling relationships can be established by using node coupling, and fixed constraints can be applied to the coupling points of the gearbox mounting holes.

[0086] Step 13: Establish a speed loading curve and a torque loading curve to ensure that the speed increases from zero until the operating speed is reached after the torque loading is completed.

[0087] Step Fourteen: A rigid body planar element can be created at the input end of the gear shaft of the input gear to apply the rotational speed loading curve; a rigid body planar element can be created at the output end of the gear shaft of the output gear to apply the torque loading curve. The rigid body planar element must be coupled one-to-one with the solid node of the gear shaft.

[0088] Step 15: Establish and apply the system damping curve;

[0089] Step 16: Establish vibration output simulation nodes at the center points on both sides of the spindle, and establish gearbox vibration output simulation nodes at the gearbox vibration measurement points;

[0090] Step 17: Set the solution parameters, including but not limited to total time and time step;

[0091] Step 18: Solve the problem;

[0092] Step 19: Observe the stress changes and contact state changes during gear meshing;

[0093] Step 20: Extract the displacement, velocity, and acceleration changes of the vibration output simulation nodes;

[0094] Step 21: Evaluate the gear stress and vibration of the gear shaft and gearbox. The evaluation criteria may include: a) whether the contact stress meets the standard; b) whether the vibration value meets the requirements; c) whether there is edge contact.

[0095] Step 22: Modify the spiral bevel gear. Modification methods may include: a) tooth tip fillet modification; b) tooth root fillet modification; c) drum-shaped modification, etc.

[0096] Step 23: Repeat steps 3 to 22 until the gear meshing stress and the vibration of the gear shaft and gearbox all meet the design requirements.

Claims

1. A simulation-based method for modifying aerospace spiral bevel gears, characterized in that, include: Step 1: Create a 3D digital model of all parts included in the transmission system assembly except for the spiral bevel gear, including the gear shaft, bearing, bearing housing, and gearbox. Step 2: Establish a three-dimensional digital model of the mandrel corresponding to the center hole of the gear shaft. The size of the mandrel is consistent with the size of the center through hole of the gear shaft of the spiral bevel gear. Step 3: Create a 3D digital model of the spiral bevel gear including all parameters; Step 4: Assemble the 3D model of the spiral bevel gear with the models of the gear shaft, spindle, bearing, bearing housing, and gearbox to form a 3D model of the simulation analysis component; Step 5: Import the 3D digital model of the simulation analysis component into transient simulation analysis software that can perform dynamic operation simulation of the gear transmission system; Step 6: Perform finite element mesh generation on the simulation analysis components; Step 7: Establish one-to-one coupling relationships between the nodes on the outer surface of the spindle and the nodes on the inner surface of the gear shaft, as well as between the outer surface of the bearing outer ring and the inner surface of the bearing housing, the outer surface of the bearing housing and the inner surface of the gearbox mounting hole, and the inner surface of the bearing inner ring and the nodes on the outer surface of the gear shaft. Step 8: Establish material parameters based on the design materials of the parts, and assign corresponding material parameters to each part, which are spiral bevel gears, bearings, bearing housings, gearboxes, and gear shafts; Step 9: Establish and assign mandrel material parameters; Step 10: Establish the contact relationships of all gear pairs within the gearbox; Step 11: Establish bearing contact relationships; Step 12: Establish bolt connection relationships or bolt hole coupling relationships, and apply fixed constraints to the bolt hole coupling points at the gearbox mounting location; Step 13: Establish a speed loading curve and a torque loading curve to ensure that the speed increases from zero until the operating speed is reached after the torque loading is completed. Step 14: Apply a speed loading curve to the input gear shaft and a torque loading curve to the output gear shaft; Step 15: Establish and apply the system damping curve; the damping should be maintained at 20 before the speed load is completed, and the damping should be reduced to below 5 after the speed load is completed; Step 16: Establish simulation nodes for spindle vibration output and gearbox vibration output; Step 17: Set the solution parameters, including but not limited to total time and time step; Step 18: Calculate the stress, contact state, displacement, velocity, and acceleration of the gear transmission system based on steps 1 to 17. Step 19: Check the stress changes and contact state changes during gear meshing, specifically including: whether there is abnormal contact at the tooth tip or tooth root, whether there is off-center loading, and whether there is excessive stress. Step 20: Extract the displacement, velocity, and acceleration changes of the spindle vibration output simulation node and the gearbox vibration output simulation node during gear meshing; Step 21: Evaluate the gear stress and vibration of the gear shaft and gearbox, specifically including: a) whether the contact stress meets the standard; b) whether the vibration value meets the requirements; c) whether there is edge contact. Step 22: Modify the spiral bevel gear; specifically including: modifying the tooth tip fillet and tooth root fillet for excessive stress or vibration caused by abnormal contact between the tooth tip and tooth root; modifying the gear with a drum shape for excessive stress caused by edge contact; modifying the gear with a drum shape for excessive stress and vibration caused by excessive normal contact stress; and modifying the gear with a drum shape under off-center load conditions. Step 23: Repeat steps 3 to 22 until the gear meshing stress and the vibration of the gear shaft and gearbox all meet the design requirements.

2. The method according to claim 1, characterized in that, Step six specifically includes: using tetrahedral meshes for the gearbox body and hexahedral meshes for other parts to ensure analysis accuracy.

3. The method according to claim 1, characterized in that, Step nine specifically includes: its density is not greater than 1 g / cm3, and its elastic modulus is not greater than 2000 MPa.

4. The method according to claim 1, characterized in that, Step 10 specifically includes: symmetrical contact, static friction coefficient not greater than 0.15, dynamic friction coefficient not greater than 0.1, adjusting the initial contact state, eliminating initial gap and initial penetration, and ensuring that the gear pair is in proper contact.

5. The method according to claim 1, characterized in that, Step eleven specifically includes: using a convex-concave fit to simulate the contact relationship of a ball bearing, and using an inner and outer ring fit to simulate the contact relationship of a roller bearing; the convex-concave fit simulation simplifies the inner ring and roller of the ball bearing into a ring with a convex cross-section, and simplifies the outer ring of the bearing into another ring with a concave cross-section, with the gap between the two rings controlled according to the bearing clearance; the inner and outer ring fit simulation simplifies the roller bearing into two inner and outer rings, each with a rectangular cross-section, with the gap controlled according to the bearing clearance.

6. The method according to claim 1, characterized in that, Step 12 specifically includes: if bolts are required, coupling the outer surface nodes of the bolts to the inner surface nodes of the bolt holes one-to-one; if bolt hole coupling is required, coupling the inner surface nodes of the two bolt holes to be connected into one node.

7. The method according to claim 1, characterized in that, Step fourteen specifically includes: First, a first rigid body planar element is established at the input end of the gear shaft of the input gear. The first rigid body planar element needs to be coupled one-to-one with the solid node of the gear shaft of the input gear. A speed loading curve is applied to the first rigid body planar element. A second rigid body planar element can be established at the output end of the gear shaft of the output gear. The second rigid body planar element needs to be coupled one-to-one with the solid node of the gear shaft of the output gear. A torque loading curve is applied to the second rigid body planar element.

8. The method according to claim 1, characterized in that, Step sixteen specifically includes: establishing vibration output simulation nodes at the center points on both sides of the spindle, and establishing gearbox vibration output simulation nodes at the gearbox test vibration measurement points.

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