Research on correction method of inertia factor of starting section of gap flow opening in hydraulic rock drill

ABSTRACT

Large pulsation and impact occur during the working process of hydraulic rock drill, which has a negative influence on the system. Aiming at this phenomenon, the related characteristics of hydraulic fluid inertia are studied in this paper. The dynamic model of impact and reversing mechanism of rock drill is established. Through the parameter analysis of the model, the concepts of hard parameter quantity and soft parameter quantity are proposed. The influence coefficient C of the initial section of crevice flow including the influence of fluid inertia is deduced, and the comprehensive factors such as hydraulic oil velocity, unstable flow and friction resistance are analyzed, The value of soft parameter quantity ζ is (ξ+1) ~ (ξ+ 1.5)。The pressure test of the working chamber is designed and 7 groups of data are obtained. Through data analysis, the influence of C on the simulation results is obtained, which has a great influence on the reversing valve. The deviation of simulation data of left and right valve chamber pressure is increased from ± 8% to ± 3%. It has a certain impact on the impact piston. The deviation of simulation data increases from ± 5% to ± 3%, and has little impact on the accumulator. The deviation of simulation data increases from ± 4% to ± 3%.   

KEYWORDS:

• Hydraulic rock drill
• impact mechanism
• reversing mechanism
• gap flow
• inertia
• coefficient correction method

Acknowledgments

The authors would like to acknowledge the academic and technical supports of Hunan University of Arts and Science. This work was supported by the Natural Science Foundation of Hunan Province of China (No. 2019JJ50404), and Key Projects of Hunan Provincial Department of Education (No. 21A0423).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Y.L. did the methodology, writing review and editing; Y.T. and B.Z. did the experiment and analysis, writing review and editing; L.Y. did the supervision, resources and review. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

The pressures data used to support the findings of this study are included within the article.

Additional information

Funding

This research was funded by Natural Science Foundation of Hunan Province of China, Grant Number 2019JJ50404, and Key Projects of Hunan Provincial Department of Education, Grant Number 21A0423.

Notes on contributors

Yelin Li

Yelin Li, Ph.D., associate professor, is engaged in the design and manufacturing of electromechanical hydraulic integration of mining machinery and the research on fault diagnosis of hydraulic system.

Yi Tu

Yi Tu, Ph.D., associate professor, is engaged in research on complex fluid systems and heat dissipation technology with high heat flux.

Bin Zeng

Bin Zeng, Ph.D., Professor, is engaged in the manufacturing of engineering machinery and equipment and the research on injection molding of metal powder.

Liang Yin

Liang Yin, Ph.D., lecturer, is engaged in the research of engine combustion and thermal protection technology.