Temperature impact analysis of star gear bearing inner ring based on under-race lubrication passage

He-yun Bao,Chun-lei Wang,Feng-xia Lu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.12

In order to reduce the inner ring temperature and the oil consumption, temperature impact of star gear bearing inner ring based on under-race lubrication passage is analyzed, the flow and temperature fields of the inner ring are simulated using the realizable k-ɛ turbulence model based on the computational fluid dynamics (CFD) method, and experimental verification is performed. The results indicate that adding annular grooves to the star gear cylindrical roller bearing has a significant impact in reducing the temperature of the inner ring, and annular grooves with different cross-sectional sizes have different impacts in reducing the temperature of the inner ring. When the cross-sectional area of the annular grooves is 5 × 1.5 mm, the temperatures of the inner raceway of the left and right bearing decrease from 123.95 and 111.98 °C to 104.3 and 101.4 °C, respectively.

Nonlinear dynamic analysis of an external gear system with meshing beyond pitch point

He-yun Bao,Guang-hu Jin,Feng-xia Lu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.12

A two-dimensional non-linear dynamics model of a gear with meshing beyond pitch point with six degrees has been established, considering time-varying meshing stiffness, time-varying bearing stiffness, time-varying friction, backlash and bearing clearance. Timevarying meshing stiffness is computed by using material mechanics method. The friction coefficient of Coulomb model and the friction coefficient of EHL theory are analyzed and compared in dynamic response. The global bifurcation characteristics caused by input speed, backlash, bearing clearance and damping are investigated. The maximum Lyapunov exponent which leads to chaos characters effect of changing parameters is analyzed. The verification experiment is carried out on the CL-100 test rig. Meshing frequency has main impact on vibration acceleration of ordinary spur gear and double meshing frequency has main impact on vibration acceleration of gear with meshing beyond pitch point. The results show that the gear with meshing beyond is better than ordinary spur gear whether in bifurcation characteristics or in vibration acceleration response.

Oil film deposition characteristics and judgment of lubrication effect of splash lubricated gears

Feng-xia Lu,Kun Wei,Meng Wang,Mou Li,He-yun Bao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5

To study the oil film deposition characteristics of splash lubricated gears and determine whether their meshing area is completely lubricated, this study proposes the concept of judging the splash lubrication-deposition characteristics-inlet oil film thickness-lubrication effect. The critical oil film thickness that characterizes the full lubrication of the gear meshing area was obtained as 14.5428 μm by using elastohydrodynamic lubrication (EHL) theory. Based on computational fluid dynamics (CFD) method, based on the renormalization group (RNG) k-ɛ two-equation turbulence model, dynamic mesh model and volume of fluid (VOF) model, the numerical calculation of the intermediate gearbox in splash lubrication is carried out. The oil film deposition thickness of the gear tooth that was about to enter the meshing area was calculated to be 95.6207 μm. It was found that the meshing area is fully lubricated under the rated operating conditions.

Parameter design method for the heat transfer performance of a fan-driven gearbox under planetary gear opening and oil-return conditions

Feng-xia Lu,Lijuan Yuan,Zhiqiang Zhao,Chun-lei Wang,He-yun Bao 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.9

On the basis of the computational fluid dynamics (CFD) method, this study calculates the surface convective heat transfer coefficients of the sun gear, planetary gear, ring gear, and bearing before and after the opening of the planetary gear of a fan-driven gearbox. A numerical fitting method is used to establish the calculation model of the convective heat transfer coefficients of the sun gear, planetary gear, ring gear, and bearing under the open-hole oilreturn condition. The convective heat transfer coefficients of each element are compared before and after the hole is bored, and the design method for the gearbox parameters with the objective of heat transfer performance is proposed. Result shows that the convective heat transfer coefficients of each element are increased after oil is returned from the hole of the planetary gear, and the change rate of the convective heat transfer coefficient of the raceway in the planetary gear bearing is the highest. When the aperture of the planetary gear is 7 mm and the number of holes is four, the heat transfer performance of the gearbox is the best. The maximum error between the convection heat transfer coefficient fitting formula value and the CFD simulation calculation result is 1.0558 %.

Gene Microarray Assessment of Multiple Genes and Signal Pathways Involved in Androgen-dependent Prostate Cancer Becoming Androgen Independent

Liu, Jun-Bao,Dai, Chun-Mei,Su, Xiao-Yun,Cao, Lu,Qin, Rui,Kong, Qing-Bo Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

To study the gene expression change and possible signal pathway during androgen-dependent prostate cancer (ADPC) becoming androgen-independent prostate cancer (AIPC), an LNCaP cell model of AIPC was established using flutamide in combination with androgen-free environment inducement, and differential expression genes were screened by microarray. Then the biological process, molecular function and KEGG pathway of differential expression genes are analyzed by Molecule Annotation System (MAS). By comparison of 12,207 expression genes, 347 expression genes were acquired, of which 156 were up-ragulated and 191 down-regulated. After analyzing the biological process and molecule function of differential expression genes, these genes are found to play crucial roles in cell proliferation, differntiation, cell cycle control, protein metabolism and modification and other biological process, serve as signal molecules, enzymes, peptide hormones, cytokines, cytoskeletal proteins and adhesion molecules. The analysis of KEGG show that the relevant genes of AIPC transformation participate in glutathione metabolism, cell cycle, P53 signal pathway, cytochrome P450 metabolism, Hedgehog signal pathway, MAPK signal pathway, adipocytokines signal pathway, PPAR signal pathway, TGF-${\beta}$ signal pathway and JAK-STAT signal pathway. In conclusion, during the process of ADPC becoming AIPC, it is not only one specific gene or pathway, but multiple genes and pathways that change. The findings above lay the foundation for study of AIPC mechanism and development of AIPC targeting drugs.

Nonlinear tribo-dynamic model of helicopter mid-reducer system under light loss of lubrication

Feng-xia Lu,Xuechen Cao,He-yun Bao,Rupeng Zhu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.11

When the helicopter tail transmission system loses oil due to damage, the system needs to persist for 30 minutes. Therefore, the nonlinear tribo-dynamics model of the helicopter intermediate reducer (HIR) is established, which is coupled with the loss of oil lubrication. To simulate condition of the HIR system under the loss of lubrication (LOL), this study begins by establishing a complete HIR system CFD model, and analyse the lubrication of the gear tooth surface and the oil churning/windage under different lubrication conditions. Then, a coupled model based on the result of the CFD is proposed to calculate the coefficient of friction (COF) under the condition of light loss of lubrication (LLOL). The results show that COF gradually decreases first and then increases rapidly.

Vocal Effort Detection Based on Spectral Information Entropy Feature and Model Fusion

( Hao Chao ),( Bao-yun Lu ),( Yong-li Liu ),( Hui-lai Zhi ) 한국정보처리학회 2018 Journal of information processing systems Vol.14 No.1

Vocal effort detection is important for both robust speech recognition and speaker recognition. In this paper, the spectral information entropy feature which contains more salient information regarding the vocal effort level is firstly proposed. Then, the model fusion method based on complementary model is presented to recognize vocal effort level. Experiments are conducted on isolated words test set, and the results show the spectral information entropy has the best performance among the three kinds of features. Meanwhile, the recognition accuracy of all vocal effort levels reaches 81.6%. Thus, potential of the proposed method is demonstrated.

Vocal Effort Detection Based on Spectral Information Entropy Feature and Model Fusion

Chao, Hao,Lu, Bao-Yun,Liu, Yong-Li,Zhi, Hui-Lai Korea Information Processing Society 2018 Journal of information processing systems Vol.14 No.1

Vocal effort detection is important for both robust speech recognition and speaker recognition. In this paper, the spectral information entropy feature which contains more salient information regarding the vocal effort level is firstly proposed. Then, the model fusion method based on complementary model is presented to recognize vocal effort level. Experiments are conducted on isolated words test set, and the results show the spectral information entropy has the best performance among the three kinds of features. Meanwhile, the recognition accuracy of all vocal effort levels reaches 81.6%. Thus, potential of the proposed method is demonstrated.

Feature Extraction Based on DBN-SVM for Tone Recognition

Chao, Hao,Song, Cheng,Lu, Bao-Yun,Liu, Yong-Li Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.1

An innovative tone modeling framework based on deep neural networks in tone recognition was proposed in this paper. In the framework, both the prosodic features and the articulatory features were firstly extracted as the raw input data. Then, a 5-layer-deep deep belief network was presented to obtain high-level tone features. Finally, support vector machine was trained to recognize tones. The 863-data corpus had been applied in experiments, and the results show that the proposed method helped improve the recognition accuracy significantly for all tone patterns. Meanwhile, the average tone recognition rate reached 83.03%, which is 8.61% higher than that of the original method.

Feature Extraction based on DBN-SVM for Tone Recognition

Hao Chao,Cheng Song,Bao-Yun Lu,Yongli Liu 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.1

An innovative tone modeling framework based on deep neural networks in tone recognition was proposed inthis paper. In the framework, both the prosodic features and the articulatory features were firstly extracted asthe raw input data. Then, a 5-layer-deep deep belief network was presented to obtain high-level tone features. Finally, support vector machine was trained to recognize tones. The 863-data corpus had been applied inexperiments, and the results show that the proposed method helped improve the recognition accuracysignificantly for all tone patterns. Meanwhile, the average tone recognition rate reached 83.03%, which is 8.61%higher than that of the original method.