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Shock and Vibration
Volume 2018, Article ID 8963750, 11 pages
https://doi.org/10.1155/2018/8963750
Research Article

Impact System Dynamic Characteristics of Hydraulic Rock Drill Based on an Overlapped Reversing Valve

Hunan Province Cooperative Innovation Center for the Construction & Development of Dongting Lake Ecological Economic Zone, Hunan University of Arts and Science, Changde 415000, China

Correspondence should be addressed to Yelin Li; moc.nuyila@3040nileyil

Received 26 February 2018; Revised 26 June 2018; Accepted 1 August 2018; Published 19 September 2018

Academic Editor: Miguel Neves

Copyright © 2018 Yelin Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

For the phenomenon of a hydraulic rock drill based on an underlapped reversing valve, the mechanical structure of the overlapped reversing form was proposed, which affected the pressure pulsation of the impact system, and motion of the impact piston was analyzed. The model of a hydraulic rock drill was built based on Newton’s laws. The initial lead size of the reversing point was calculated by the equilibrium position of the damping piston and final velocity of the impact piston. The size of the overlapped reversing valve was designed and the best impact interval was calculated, according to pressure characteristic curves in the piston of the front-rear chamber and in the reversing valve of the left-right chamber, and the damping piston floating feature had an impact on initial lead size of the reversing point. The advantages of the overlapped reversing valve were analyzed, by contrasting the pressure pulsation of the impact system and motion of the impact piston with the underlapped reversing valve. The inner mechanism experiment of the hydraulic rock drill was designed to test the pressure characteristic curves in the piston of the front-rear chamber and in the reversing valve of the left-right chamber. The model of the overlapped reversing valve was verified by the experiment.