CN-122021175-A - Rigidity optimization method and aluminum alloy shell

Abstract

The invention belongs to the technical field of transmission shell design, and particularly discloses a rigidity optimization method and an aluminum alloy shell, wherein the rigidity optimization method comprises the steps of designing an aluminum alloy shell the first edition, analyzing strength by a finite element method and reinforcing weak points to obtain a pretreatment shell; the method comprises the steps of carrying out static and dynamic stiffness analysis to obtain stiffness distribution characteristics and dynamic stiffness curves, determining a target frequency range as an optimized frequency range by combining with the working characteristics of a transmission gear, analyzing the mode shape of a shell in the frequency range, identifying a weak area and a strong area of stiffness, arranging a reinforcing structure in the weak area and connecting the weak area to the strong area, repeating the stiffness analysis and the reinforcing step for iterative optimization until the dynamic stiffness curves reach the standard, and carrying out fatigue test verification to pass through a post-curing design. The invention effectively improves the static and dynamic stiffness properties of the aluminum alloy shell, reduces the failure risk of the shaft teeth, simultaneously meets the light-weight requirement, shortens the product development period, reduces the research and development cost, and ensures the stable operation of the transmission system of the speed changer.

Inventors

• WANG KAI
• DONG TIANQI
• ZHAO BIN
• ZHANG HAITAO
• LI WANYING
• CHEN XIAOLI
• WANG PENGCHUAN
• WANG YICHEN

Assignees

• 陕西法士特汽车传动集团有限责任公司

Dates

Publication Date

20260512

Application Date

20260210

Claims (8)

1. 1. A method for optimizing stiffness of an aluminum alloy housing, comprising: s1, designing an aluminum alloy shell the first edition, performing strength analysis based on a finite element method, and reinforcing weak points to obtain a pretreated aluminum alloy shell; S2, carrying out static stiffness analysis and dynamic stiffness analysis on the pretreated aluminum alloy shell to obtain stiffness distribution characteristics and dynamic stiffness curves; S3, determining a target frequency range related to gear fatigue by combining the working characteristics of the transmission gear, and taking the target frequency range as a rigidity optimization frequency range; s4, analyzing and optimizing the mode shape of the aluminum alloy shell in the frequency band, and identifying a weak rigidity area and a stronger rigidity area; s5, arranging a reinforcing structure in the weak rigidity area, and connecting the reinforcing structure with the area with stronger rigidity; And S6, repeating the steps S2 to S5 for iterative optimization on the aluminum alloy shell provided with the reinforcing structure until the dynamic stiffness curve meets the preset requirement, and curing the aluminum alloy shell after reaching the standard through fatigue test verification.
2. 2. The method for optimizing rigidity according to claim 1, wherein in the step S2, the static rigidity analysis is performed by restraining the suspension of the shell, applying a load in a specified direction to the bearing holes and monitoring the corresponding displacement, calculating the static rigidity of each direction and each bearing hole according to the ratio of the load to the displacement, and simultaneously comparing the static rigidity with the static rigidity of the cast iron shell to determine the position and the direction of the bearing hole with poor rigidity.
3. 3. The method for optimizing rigidity according to claim 2, wherein in step S2, dynamic load is applied in a set frequency range for bearing holes and directions with poor rigidity by dynamic rigidity analysis, a dynamic equation is established by finite element analysis software, dynamic displacement response is obtained by combining harmonic response analysis, and a dynamic rigidity curve is calculated according to the ratio of the dynamic load to the dynamic displacement response.
4. 4. The method of optimizing rigidity according to claim 1, wherein the target frequency range in step S3 includes a rotation frequency of the output gear and a specified frequency multiplication range thereof under a target gear condition, and the specified frequency multiplication range is 2-5 frequency multiplication.
5. 5. The method of optimizing stiffness according to claim 1, wherein the region of higher stiffness in step S4 is a region of minimum vibration displacement in the mode shape, and the region of weak stiffness is a region of maximum vibration displacement in the mode shape.
6. 6. The method of claim 5, wherein the reinforcement structure in step S5 is a cross-type rib, and the region of higher rigidity includes a bolt-pack position, a joint surface position, and a suspension position, and the cross-type rib is connected to the bolt-pack position, the joint surface position, and the suspension position.
7. 7. A method of optimizing stiffness as claimed in claim 6, wherein the cross-type ribs are X-type cross-type ribs.
8. 8. An aluminum alloy shell, characterized in that the aluminum alloy shell is prepared by the rigidity optimizing method according to any one of claims 1-7, wherein a reinforced structure is arranged in a weak rigidity area of the shell, and the reinforced structure is connected with a region with stronger rigidity.

Description

Rigidity optimization method and aluminum alloy shell Technical Field The invention belongs to the technical field of transmission shell design, and particularly relates to a rigidity optimization method and an aluminum alloy shell. Background The transmission shell is a core component of a transmission system, and has the core effects of ensuring the meshing precision of gears, improving the supporting stability of bearings, reducing vibration and noise, optimizing lightweight design, improving structural durability and guaranteeing sealing and lubrication. The aluminum alloy material has excellent properties such as low density, high specific strength, easy workability and the like, so that the aluminum alloy material becomes an ideal material for a transmission shell. However, the aluminum alloy has the inherent defects of low hardness, low elastic modulus and large thermal expansion coefficient, so that the aluminum alloy shell has obvious differences with the cast iron shell in deformation and rigidity, and the stable operation of the transmission system is further affected. For example, in a certain type of high-torque transmission, gear pitting faults occur only in2 cycles when the aluminum alloy shell is adopted for the packing fatigue test, and the aluminum alloy shell is adopted for the cast iron shell, and the aluminum alloy shell successfully passes through 10-cycle test verification. Through strength calculation, the safety coefficient of the aluminum alloy shell is not lower than that of the cast iron shell, and the core reason that the rack of the aluminum alloy shell performs poorly is that the shell has insufficient rigidity, so that the problems of pitting, tooth breakage and other failure of the inner shaft teeth in the shell occur. In order to make up the rigidity defect of the aluminum alloy material, the reinforced oblique crossed ribs are usually designed on the shell in the industry, but the arrangement positions, the structural forms and the connection modes of the oblique crossed ribs are all verified by experience of a designer and a later test, so that the aluminum alloy shell is long in development period, high in research and development cost and difficult to ensure the rigidity optimization accuracy. Disclosure of Invention In view of the above problems, an object of the present invention is to provide a rigidity optimizing method and an aluminum alloy housing. The technical scheme of the invention is that the rigidity optimization method is used for rigidity optimization of the aluminum alloy shell and comprises the following steps: s1, designing an aluminum alloy shell the first edition, carrying out strength analysis based on a finite element method, and reinforcing weak points to obtain the pretreated aluminum alloy shell. S2, carrying out static stiffness analysis and dynamic stiffness analysis on the pretreated aluminum alloy shell to obtain stiffness distribution characteristics and dynamic stiffness curves. S3, determining a target frequency range related to gear fatigue by combining the working characteristics of the transmission gear, and taking the target frequency range as a rigidity optimization frequency range. S4, analyzing and optimizing the mode shape of the aluminum alloy shell in the frequency band, and identifying the weak rigidity area and the strong rigidity area. S5, arranging a reinforcing structure in the weak rigidity area, and connecting the reinforcing structure with the area with higher rigidity. And S6, repeating the steps S2 to S5 for iterative optimization on the aluminum alloy shell provided with the reinforcing structure until the dynamic stiffness curve meets the preset requirement, and curing the aluminum alloy shell after reaching the standard through fatigue test verification. Further, in the step S2, the static stiffness analysis is carried out by restraining the suspension of the shell, applying load in a specified direction to the bearing holes, monitoring corresponding displacement, calculating the static stiffness of each direction and each bearing hole according to the ratio of the load to the displacement, and simultaneously comparing the static stiffness with the static stiffness of the cast iron shell to determine the position and the direction of the bearing hole with poor stiffness. Further, in the step S2, dynamic load is applied to the bearing hole and direction with poor rigidity in the dynamic rigidity analysis, a dynamic equation is solved by establishing a model through finite element analysis software, dynamic displacement response is obtained by combining harmonic response analysis, and a dynamic rigidity curve is calculated according to the ratio of the dynamic load to the dynamic displacement response. Further, the target frequency range in step S3 includes the rotation frequency of the output gear and the designated frequency multiplication range thereof under the target gear working condition, and the designated freq