Research On The Damage Under Working Load And Damping Plan For Roadheader Cutting Reducer

This research was financially supported by the subproject “Research of Smart Heavy-Duty Hard-Rock-Cutting Roadheader”(2012AA06A405)from National High-tech Research and Development Projects(863, Smart Technology and Equipment of Drifting-Digging for Coal). The research object is to promote the cutting capability, intelligentized degree and reliability of roadheader through high self-made ability for key components.Cutting reducer of roadheader is an important power drive unit. The tough working condition enables the reducer to exhibit some particular features, such as heavy-loading, bug easily checking and removing, lower vibration and noise, and higher reliability. Therefore, it is urgent to develop a set of damage mechanism theories of cutting reducer under task loading and an effective anti-vibration-and-noise approach, not only to facilitate the present equipment, but also to provide theoretic reference for future heavy-load and super heavy-load mining equipment. This research displays dual-value of both scientific and social ones.In addition, The national youth science fund project “Study on the Coupling Mechanism of Physical and Mechanical Parameters of Tubular Damping Structure with Transitional Layer”(514052323)and Research Project Supported by Shanxi Scholarship Council of China “Study on the N-Combination-Layer Damping Characteristics of Viscoelastic Suspension Based on the Coupling Mechanism of Physical and Mechanical Parameters”( 2012-073) provide important funding support.The main research contents are:1. The dynamic model under task load of cutting reducer was developed and its analytical solution was derived. Based on Newton’s second law of motion and concentrated-parameter method, the high-order nonlinear coupling dynamic model was proposed starting with purely torsional vibration model of gear pair and proceeding with single meshing driving model considering several nonlinear factors of two stage planet gear structure. To address the difficulty of solving of the model caused by multi-parameter, nonlinear factors, stiffness displacement of planet gear and coupling between shaft and box, the FE method was employed to obtain the time-domain response of bearing and inner gear and dynamic meshing force, based on which the damage mechanism was studied. Furthermore, the frequency-domain response was obtained to master the low frequency distribution based on which the exciting frequencies of the reducer system were got.2. Vibration test of roadheader under variable cutting-artificial-rock conditions was conducted in state engineering lab for mining excavation machine(Tai Yuan, China). The associated response characters of reducer, crawler, operation platform and electronic control box in time and frequency domains were analyzed through logged data. Additionally, the vibration severity and comfort exposed to the vibration were evaluated. This part accumulates essential basic data for performance optimization of analogous reducers and research of high-end equipment.3. Mode analysis of cutting reducer coupling its shell were studied theoretically and experimentally. The mode analysis gives the low-order natural frequencies which are the basis of dynamic research and vibration isolation. Also, the force hammer was employed for the mode experiment using SMSR mode to acquire the low-order natural frequencies and the associated vibration mode, therefore validating the theoretical model by error analysis.4. Vibration test of the reducer was also carried out on the vibration test bench to log the acceleration data of gear rings in time domain for validation of the theoretical model. The error observation gives the expected results that the theoretical solution is efficient for dealing with closed driving system quickly and accurately.5. Vibration damping strategy was proposed and vibration control effect between the original and the damping reducers were studied comparatively from the theoretic point of view. For validation, the real vehicle test of analogous anti-vibration structures indirectly verified feasibility of the proposed damping strategy for tubular loading component.To sum up, the achievement of this thesis can provide theoretic basis and references for task load damage, bug removing and vibration and noise control of cutting reducer, which provides ideas and methods for driving system of future heavy and super heavy digging and mining equipment.