Analysis And Experimental Research On Alternating Impact Characteristic Of Compressed Air Electric Hammer

Compressed air electric hammer is an important type of power-driven tools, belonging toroad construction products. This electric hammer is a hand-held power-driven tool, which canrotate in impact process. It is also a typical kind of fluid impact machinery, mainly used indrilling and slotting of working mediums such as concrete, wood, metal, ceramics and plastics.And it is essential in engineering projects in road construction, electrical conduit installationand household upholstery, etc. Nowadays, electric hammer is still under research anddevelopment in our country, therefore testing the alternating impact performance ofcompressed air electric hammer plays an important role in the study of impact piston motion,structure analysis, indicator testing and performance improvement.The Project sponsored by Natural Science Foundation of China “Research of Dynamicsof Impact Machines Driven by Alternating Fluid and Control”(No.11272122). In order tosatisfy engineering requirements, this dissertation chooses a domestic compressed air electrichammer RDH06P as the detecting target, proposes an effective measurement method ofimpact characteristics, establishes the measuring test-bed of compressed air electric hammerand develops the impact characteristics measurement system. The method can detect theimpact performance of piston inside the air cylinder, analyzes its motion law, and accuratelyacquire the related characteristic parameters such as the impact frequency and impact energy.The main research are as follows:Propose a new method of detecting impact characteristics for the electric hammer, whichis based on the electromagnetic induction theory. And analyze the dynamic performance ofmagnetic sense speed detectors and complete the design of tacho-generator.Design hardware of the data acquisition system with LabJack and software of thedetection system in LabVIEW, build the testing system of impact performance for compressedair electric hammer, and conduct calibration tests to ensure the test accuracy demand.Chooses the compressed air electric hammer RDH06P as the detection target, whosehigh speed and high accelerated speed reciprocating motion is drove by air pressure. Detectkinetic characteristics of the impact piston and accurately calculate its main functionparameters of impact energy, impact frequency and impact power.Further study the performance of its alternating impact mechanism--the impact pistonrebound phenomenon, and conduct wave mechanics analysis. The study of impact pistonrebound experiment verifies that different nature of working mediums have different rebound velocity.By the new detection method and detection system, the testing error between themeasured value and the theoretically calculated value is within5%. This simple and efficientdetection method together with the accurate and reliable testing result provide effective basisfor product performance testing, quality inspection and performance improvement.