Prediction method of ultimate bearing capacity of transmission casing under engine shock

Abstract

The invention discloses a method for predicting the ultimate bearing capacity of a transmission casing under the action of an engine impact, which makes full use of the advantages of a short linear elastic finite element analysis calculation period and an accurate static safety factor to predict the structural fracture position, and quickly determines multiple transmission casings. Weak strength position; through elastoplastic finite element analysis, the plastic strain of multiple strength weakness positions of the transmission casing is calculated, and the minimum torque among the multiple strength weakness positions when the plastic strain is equal to the material elongation is used as the transmission casing fracture criterion , predicts the ultimate bearing capacity of the transmission casing; since the material elongation is the plastic strain when the structure is fractured, which has a strong correspondence with the structural fracture, the material elongation is used to evaluate the ultimate bearing capacity of the transmission casing, which is more accurate and more accurate. high.

Description

technical field [0001] The invention relates to a method for predicting the ultimate bearing capacity of a transmission casing, in particular to a method for predicting the ultimate bearing capacity of a transmission casing under the action of an engine impact. Background technique [0002] The ultimate bearing capacity of the transmission casing is the maximum load capacity that the transmission casing can bear when it breaks and fails. As an important basic part, the transmission housing should have enough strength to resist the gear meshing force caused by the strong torque of the engine and the inertial force of the transmission caused by the uneven road, so as to support the gear shaft, protect the gear transmission mechanism, and meet the requirements of the whole vehicle for the transmission. Different torque and speed requirements. [0003] In the process of product design, two technical means are usually used to obtain the ultimate bearing capacity of the transmiss...

AI Technical Summary

Problems solved by technology

The application of simulation technology to obtain the ultimate bearing torque of the transmission case is fast and can be predicted in the early stage of product development, but the following problems exist in the current simulation technology; ① There are many forms of stress, such as Mises stress, maximum principal stress, maximum Shear stress, etc.; stress has many states, such as stretching, bending, torsion, etc.; material strength has many types, such as tensile strength, compressive strength, bending strength, etc., which stress and which material to use Calculation of the ultimate load-bearing torque based on the strength is highly subjective, so that the calculation of the limit load-bearing torque varies greatly and has low precision, which cannot meet the needs of product development

② The safety factor evaluation comprehensively considers the impact of structural stress type, stress state and material strength corresponding to different stress states, etc., to a certain extent avoids the subjectivity of engineers, but the calculated ultimate bearing torque is far lower than the test value, which is relatively conservative, so that The physical prototype of the transmission housing has a large strength backup coefficient, heavy weight, and high cost, which seriously affects product competitiveness.

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