A new energy vehicle transmission system nonlinear dynamics modeling method

Abstract

The application discloses a new energy automobile transmission system nonlinear dynamics modeling method, which comprises the following steps: (1) a bearing dynamics model is established, and bearing support force is calculated based on Hertz theory; (2) a helical gear pair dynamics model is established, and helical gear pair meshing force is calculated; (3) a new energy automobile transmission system nonlinear vibration differential equation is established, a dimensionless vibration differential equation is substituted into system basic parameters to solve the differential equation set, and the nonlinear characteristics of the new energy automobile transmission system are explored; the new energy automobile transmission system nonlinear dynamics model is established, and the related technology blank of the current new energy automobile transmission system dynamics modeling is filled.

Description

Technical Field

[0001] This invention relates to the field of gear nonlinear dynamics technology, and in particular to a nonlinear dynamics modeling method for a new energy vehicle transmission system. Background Technology

[0002] The new energy vehicle industry is a strategic emerging industry, and developing new energy vehicles is an effective measure to promote energy conservation and emission reduction. Currently, energy and environmental problems are becoming increasingly serious, and vigorously developing new energy vehicles is an effective way to solve environmental problems and a powerful measure to achieve national ecological civilization construction. As a crucial part of transmitting power in a vehicle, the transmission system's vibrations and impacts are detrimental to the overall vehicle system operation. Due to the influence of nonlinear factors such as meshing stiffness, tooth backlash, transmission error, and bearing clearance, the transmission system of new energy vehicles exhibits complex nonlinear vibration characteristics. Avoiding resonance points in the transmission system and improving system operational stability are currently key research areas in the nonlinear dynamics of new energy vehicles. Therefore, research on the nonlinear dynamics of new energy vehicle transmission systems has high academic value for enriching and expanding the theoretical system of nonlinear dynamics in new energy vehicle transmission systems, and has important engineering application value for vibration and noise control in new energy vehicles. Current technology lacks research on the nonlinear dynamics of new energy vehicle transmission systems.

[0003] To address the aforementioned problems, this invention proposes a nonlinear dynamics modeling method for new energy vehicle transmission systems. This method establishes a nonlinear dynamics model of the bearing, calculates the bearing support force based on Hertzian contact theory, then establishes a dynamics model of the helical gear pair, considering nonlinear factors such as time-varying meshing stiffness and transmission errors, and calculates the meshing force of the helical gear pair. Subsequently, a nonlinear dynamics model of the new energy vehicle transmission system is established and dimensionless, and the Runge-Kutta method is used to numerically solve the differential equations. This method can both promote engineering technology development and generate significant socio-economic benefits. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies and fill the gaps in related technologies, this invention proposes a nonlinear dynamic modeling method for the transmission system of new energy vehicles. This method establishes a nonlinear dynamic model of bearings and calculates the bearing support force based on Hertzian contact theory. Then, a dynamic model of helical gear pairs is established, taking into account nonlinear factors such as time-varying meshing stiffness and transmission error, and the meshing force of helical gear pairs is calculated. Subsequently, a nonlinear dynamic model of the transmission system of new energy vehicles is established and dimensionless, and the Runge-Kutta method is used to numerically solve the differential equation system.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: A nonlinear dynamics modeling method for a new energy vehicle transmission system, characterized by comprising the following steps: Step (1): Establish a bearing dynamic model, and use Hertzian theory to calculate the bearing support force and bearing rolling elements. The directional forces are respectively: , ; in, This refers to the number of rolling elements in the bearing. For the deformation stiffness of the rolling element, These represent the vertical and horizontal displacements of the center point of the bearing's inner ring, respectively. For the first The rotation angle of each rolling element; For bearing clearance, It is a nonlinear influence function. This refers to the bearing contact angle; Step (2): Establish the dynamic model of the helical gear pair. The directional meshing forces are respectively; , ; in, For time-varying meshing stiffness, It is a nonlinear gap function. For meshing damping, This is the equivalent displacement of the meshing line. Normal pressure angle, The helix angle of a helical gear; Step (3): Establish the nonlinear vibration differential equation of the new energy vehicle transmission system, considering 24 degrees of freedom, namely: ; in, These represent the six bearings in Degrees of freedom in the radial direction, These represent the six bearings in Degrees of freedom in the radial direction, These represent the four gears in Radial vibration degree of freedom, These represent the four gears in Radial vibration degree of freedom, Let each of the four gears represent its rotational degrees of freedom in the axial direction. Establish the vibration differential equation for the transmission system of the new energy vehicle: , , , , , , , , , , ; in, For first and second order differentials, For integration time, Bearings quality gears quality Six bearings respectively Degrees of freedom of direction Each of the four gears is in Degrees of freedom of direction Six bearings respectively Degrees of freedom of direction Each of the four gears is in Degrees of freedom of direction These represent the torsional degrees of freedom of the four gears. These are the equivalent displacements of the meshing lines of the first and second stage gear pairs, respectively. These are the support damping parameters for the six bearings. These are the support damping components for the four gears. These are the meshing damping of the first and second stage gear pairs, respectively. Bearings With gears ,gear With bearings bearings With gears ,gear With gears ,gear With bearings bearings With gears ,gear With bearings Shear stiffness between These are the meshing stiffnesses of the first and second stage gear pairs, respectively. This refers to the torsional stiffness between the first-stage driven wheel and the second-stage driving wheel. There are six bearings respectively Directional bearing force, There are six bearings respectively Directional bearing force, These are the backlash functions for the first and second stage gear pairs, respectively. It is the acceleration due to gravity. These are the input and output torques, respectively. Solving the aforementioned set of vibration differential equations yields the dynamic response characteristics of the new energy vehicle transmission system.

[0006] Compared with existing technologies, the beneficial effects of this invention are: the proposed dynamic modeling method can more accurately reflect the dynamic characteristics of gear pairs in the transmission system of new energy vehicles, improve the nonlinear dynamic theory system of new energy vehicles, and provide strong support for vibration reduction, noise reduction and fault diagnosis of transmission systems of new energy vehicles. Attached Figure Description

[0007] Figure 1 This is a flowchart of the modeling method for the dynamics model of the transmission system of new energy vehicles; Figure 2 It is a bearing dynamics model; Figure 3 It is a dynamic model of a helical gear pair; Figure 4 It is a 3D model of the transmission system of a new energy vehicle; Figure 5 It is a dynamic model of the transmission system of new energy vehicles; Figure 6 This is a diagram showing the vibration response characteristics of gear pairs in the transmission system of new energy vehicles. Implementation

[0008] Embodiments of the present invention will be described with reference to the accompanying drawings, which will be further described below. Figure 1 — Figure 5 The specific embodiments of the present invention will be described in detail below.

[0009] like Figure 1 The diagram shows the flowchart of the modeling method for the dynamics model of a new energy vehicle transmission system, which includes the following steps: Step (1): Establish the bearing dynamics model as follows Figure 2 As shown, the bearing support force is calculated using Hertzian theory. Time of the first The rotation angle of each rolling element Elastic contact deformation, bearing rolling elements Directional co-operating force and nonlinear influence function: , , , ; Among them, the angular velocity of the rolling element's revolution Revolutionary speed of rolling elements bearing outer ring speed bearing inner ring speed , These represent the inner and outer ring radii, inner and outer ring angular velocities, and shaft angular velocity, respectively. This refers to the number of rolling elements in the bearing. The initial position angle of the rolling element. For bearing clearance, These represent the displacements of the bearing inner ring center point in the vertical and horizontal directions, respectively. For the deformation stiffness of the rolling element, This refers to the bearing contact angle; Step (2): Establish the dynamic model of the helical gear pair as follows Figure 3 As shown, the relative displacement on the meshing line, helical gear pair The directional meshing forces can be expressed as follows: , , ; in, The driving and driven wheels are respectively located at... Radial vibration displacement in the direction, The pressure angle of the pitch circle. These represent the axial rotational displacements of the driving and driven wheels, respectively. These are the radii of the driving wheel and the driven wheel, respectively. For time-varying propagation error, the base circle helix angle , For helical gears, The end face pressure angle, Normal pressure angle, time-varying meshing stiffness , This represents the amplitude of stiffness fluctuation. For average meshing stiffness, meshing frequency natural frequency Equivalent mass of meshing gears , For the mass of the driving wheel and the driven wheel, Given the number of teeth, the meshing damping and nonlinear backlash function are expressed as follows: , ; in For the damping ratio, It is half of the tooth flank clearance. These are the moments of inertia of the driving wheel and the driven wheel, respectively. Step (3): Three-dimensional model and dynamics of the new energy vehicle transmission system, as shown in the figure. Figure 4 , Figure 5 As shown, the nonlinear vibration differential equation of the new energy vehicle transmission system is established, considering 24 degrees of freedom, namely: ; in, These represent the six bearings in Degrees of freedom in the radial direction, These represent the six bearings in Degrees of freedom in the radial direction, These represent the four gears in Radial vibration degree of freedom, These represent the four gears in Radial vibration degree of freedom, Let each of the four gears represent its rotational degrees of freedom in the axial direction. Establish the vibration differential equation for the transmission system of the new energy vehicle: , , , , , , , , , , ; in, For first and second order differentials, For integration time, Bearings quality gears quality Six bearings respectively Degrees of freedom of direction Each of the four gears is in Degrees of freedom of direction Six bearings respectively Degrees of freedom of direction Each of the four gears is in Degrees of freedom of direction These represent the torsional degrees of freedom of the four gears. These are the equivalent displacements of the meshing lines of the first and second stage gear pairs, respectively. These are the support damping parameters for the six bearings. These are the support damping components for the four gears. These are the meshing damping of the first and second stage gear pairs, respectively. Bearings With gears ,gear With bearings bearings With gears ,gear With gears ,gear With bearings bearings With gears ,gear With bearings Shear stiffness between These are the meshing stiffnesses of the first and second stage gear pairs, respectively. This refers to the torsional stiffness between the first-stage driven wheel and the second-stage driving wheel. There are six bearings respectively Directional bearing force, There are six bearings respectively Directional bearing force, These are the backlash functions for the first and second stage gear pairs, respectively. It is the acceleration due to gravity. These are the input and output torques, respectively. Solving the aforementioned set of vibration differential equations yields the dynamic response characteristics of the new energy vehicle transmission system.

[0010] In this example, the relevant parameters of the new energy vehicle transmission system are shown in Table 1: Table 1 Parameters of New Energy Vehicle Transmission System Number of teeth 20 60 25 75 Module / mm 4 4 4 4 Pressure angle / ° 20 20 20 20 Helix angle / ° 15 15 15 15 Tooth width / mm 30 30 30 30 Substituting the relevant parameters of the transmission system, the Runge-Kutta method is used to solve the system of differential equations. Figure 6 The diagram shows the response characteristics of a two-stage helical gear pair in a new energy vehicle transmission system. This transmission system exhibits nonlinear vibration characteristics of chaotic-single-cycle-multi-cycle bifurcation. By adjusting the excitation, the vibration state of the system can be controlled, thereby improving system stability.

[0011] The above description is merely a preferred embodiment of the invention and does not constitute any limitation on the invention. Any modifications, alterations, or equivalent changes made to the above embodiments based on the essence of the invention shall still fall within the protection scope of the invention.

Claims

1. A nonlinear dynamics modeling method for a new energy vehicle transmission system, characterized in that, Includes the following steps: Step (1): Establish a bearing dynamic model, and use Hertzian theory to calculate the bearing support force and bearing rolling elements. , The directional forces are respectively: ， ； in, This refers to the number of rolling elements in the bearing. For the deformation stiffness of the rolling element, These represent the vertical and horizontal displacements of the center point of the bearing's inner ring, respectively. For the first The rotation angle of each rolling element; For bearing clearance, It is a nonlinear influence function. This refers to the bearing contact angle; Step (2): Establish the dynamic model of the helical gear pair. The directional meshing forces are respectively; ， ； in, For time-varying meshing stiffness, It is a nonlinear gap function. For meshing damping, This is the equivalent displacement of the meshing line. Normal pressure angle, The helix angle of the helical gear; Step (3): Establish the nonlinear vibration differential equation of the new energy vehicle transmission system, considering 24 degrees of freedom, namely: ； in, These represent the six bearings in Degrees of freedom in the radial direction, , , , , , These represent the six bearings in Degrees of freedom in the radial direction, These represent the four gears in Radial vibration degree of freedom, These represent the four gears in Radial vibration degree of freedom, Let each of the four gears represent its rotational degrees of freedom in the axial direction. Establish the vibration differential equation for the transmission system of the new energy vehicle: ， ， ， ， ， ， ， ， ， ， ； in, For first and second order differentials, For integration time, Bearings quality gears quality Six bearings respectively Degrees of freedom of direction Each of the four gears is in Degrees of freedom of direction Six bearings respectively Degrees of freedom of direction Each of the four gears is in Degrees of freedom of direction These represent the torsional degrees of freedom of the four gears. These are the equivalent displacements of the meshing lines of the first and second stage gear pairs, respectively. These are the support damping parameters for the six bearings. These are the support damping components for the four gears. These are the meshing damping of the first and second stage gear pairs, respectively. Bearings With gears ,gear With bearings bearings With gears ,gear With gears ,gear With bearings bearings With gears ,gear With bearings Shear stiffness between These are the meshing stiffnesses of the first and second stage gear pairs, respectively. This refers to the torsional stiffness between the first-stage driven wheel and the second-stage driving wheel. There are six bearings respectively Directional bearing force, There are six bearings respectively Directional bearing force, These are the backlash functions for the first and second stage gear pairs, respectively. It is the acceleration due to gravity. These are the input and output torques, respectively. Solving the aforementioned set of vibration differential equations yields the dynamic response characteristics of the new energy vehicle transmission system.

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