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Journal : Journal of Mechanical Engineering Science and Technology

Study on Thermal-Fluid-Solid Coupling Characteristics for Helicopter Intermediate Spiral Bevel Gear Reducer Sheng, Dongping; Yang, Jie; Su, Chun
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 8, No 2 (2024)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v8i22024p345

Abstract

In the helicopter transmission system, the intermediate reducer is particularly special. It uses bevel gear pairs to change the transmission direction and to transfer the rotational speed effectively. Therefore, an in-depth study of the spiral gear pair is crucial to improve the overall performance of the helicopter rotor system. This study focuses on the study of the thermal-fluid-solid coupling characteristics and one-way steady-state thermal finite element analysis are conducted based on volume of fluid multiphase flow simulation theory to provide strong support for the design and optimization of the helicopter intermediate reducer. Several conclusions could be obtained. Firstly, it could be found that the negative pressure of the gear engagement occurs and the absolute value increases with the rotation speed of the gear moving wall in the flow field. Secondly, the effect force such as the gear decreases with the increase of the rotational speed of the gear moving wall in the flow field. Thirdly, the contact stress could be affected significantly at different working speed while considering the thermal-fluid influence; Finally, by reasonably controlling the speed of the gear, the stress level between the teeth can be reduced while ensuring the transmission efficiency, as well as improving the service life and reliability of the gear reducer.
Dynamic Analysis and Fatigue Life Evaluation of Single Herringbone Planetary Gear System with Crack Fault Sheng, Dongping; Yang, Jie; Su, Chun
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p026

Abstract

The herringbone planetary gear transmission is widely used due to its exquisite compact structure, excellent load-bearing capacity, and stable transmission characteristics. However, root crack is one of the most common failure modes of gears. A cracked herringbone planetary gear system is taken as research object. The sun gear with crack fault is studied from the aspect of modal and transient dynamic analysis, and the related results are compared with the healthy gear. Based on the transient dynamic analysis of the herringbone teeth with cracks, a fatigue life evaluation is conducted. Firstly, the results show that no significant difference between the natural frequencies and main vibration modes of healthy gears and faulty gears could be observed. Secondly, through transient dynamic analysis, it can be found that, during the rotation process of gears and with the increase of crack depth, the stress at the crack area increases gradually. As the crack penetration length increases, the stress at the crack endpoint of the gear increases almost linearly. Additionally, by comparing cracks with different depths and penetration lengths, the depth of the crack has a greater impact on the stress of the gear compared to the crack penetration length. Finally, based on the fatigue life analysis, the depth of the crack has a significant impact on the gear life; even if the depth of the crack is not very large, it will still have a significant impact. The related research is valuable and could guide the design and optimization of herringbone planetary gear system from the point of practical application.