Study on Surface Noise Distribution of Three ring Reducer

The three ring reducer is a kind of gear drive developed in the past decade. Adopting the new conception of "parallel and movable axis" of multiple mechanisms, this kind of gear drive has many characteristics such as large transmission ratio, high efficiency and so on. As the three ring reducer has been invented only for ten years, up to date the design of the gear drive is only made with analogue method, no design theory can be followed, there exist serious vibration and noise in transmission, which limit its wide application in industry. In this paper, the transmission principle of SHQ50 reducer is studied, the surface noise distribution of the reducer, transmission ratio 49.5 , is measured and analyzed by means of sound intensity method. The 3D distribution maps of noise on top of reducer, input side and output side of reducer, and left side and right side of reducer are drawn. With the sound intensity frequency maps of each measuring point, the sources of giving out noise are analyzed. The reducer of low vibration and noise can be designed rightly according to the analysis.     

Analysis and test on vibration and acousticnoise of GWC6066 marine gearbox

The mesh stiffness of gear tooth is simulated by spring elements, the connected bolt between various housings are simplified as bar elements, and the sliding bearing and rolling bearing are simplified as spring dumping elements. Based on them, the gear-shaft-bearing-housing coupled finite element model and boundary element model of GWC6066 marine gearbox are established. Finally, the dynamic response under internal dynamic excitation is analyzed and the vibration severity, structural-borne noise and air-borne noise of the gear system are forecasted. Through the experimental modal analysis of gear system, and the test of vibration response and air pressure, the natural frequencies, vibration severity, structural-borne noise and air-borne noise are obtained. Compared with numerical results, two results show good agreement.     

Analysis on new gyratory fixed spindle cycloid drive

The current cycloid reducer drive has the shortage of needing special output mechanism, large volume and high vibration. To solve this problem, a new gyratory fixed spindle cycloid drive is designed. The drive principle of the reducer is introduced. Formula for calculating the basic parameters and tooth profile equation of cycloid gear are derived. On the basis of discussion of the mechanism and the principles of gear connection, a prototype is designed and manufactured. The results of the prototype test on the gear test rig indicate that the transmission efficiency of the new drive may reach 91.9% at rated operating conditions, the biggest vibration velocity effective value is 3.09 mm/s, and the biggest structure noise is 101.6 dB.     

风电齿轮箱传动误差分析及振动噪声预估

针对一级行星两级平行轴风电齿轮传动系统,综合考虑齿轮时变啮合刚度、啮合阻尼、传递误差等因素,建立31个自由度的弯扭轴耦合集中参数动力学模型,采用变步长Runge-Kutta法对系统动力学微分方程进行求解,得出齿轮传动系统各级传动误差;借助软件建立风电齿轮箱刚柔耦合动力学模型,并导入传动误差,采用模态叠加法求得齿轮箱轴承支反力,并将其作为声振耦合模型的边界条件,采用声学有限元法对风电齿轮箱进行振动噪声预估,并与试验结果对比分析,两者吻合良好。     

Junction stiffness analysis and vibration noise prediction of wind power speed-increase gearbox

In order to study the vibration characteristics and radiation noise of wind power speed-increase gearbox, a torsional vibration model of wind power speed-increase gearbox is established based on the analysis of supporting stiffness of bearing and contact stiffness of gear pairs. By solving the vibration differential equation with the help of Matlab, the frequency and corresponding vibration mode are obtained. With taking stiffness excitation, error exaction and meshing impact exaction into account, the dynamic finite element model of speed-increase gearbox is set up, and the dynamic response simulation is carried out. Regarding vibration displacement of the nodes on gearbox surface as boundary condition, an acoustic boundary element model of speed-increase gearbox is built. The surface acoustic pressure of gearbox and the radiation noise of field points are solved by the direct boundary element method. The results show that there is a great difference between torsion frequency and excitation frequency of wind power speed-increase gearbox, and so the resonance doesn't occur. The maximum structural noise and radiation noise mainly appear near the double octave of the gears meshing frequency of high-speed grade.     

Experimental study on vibration and structure noise of marine gear box with heavy load

The performance requirements of marine gear box are much higher than that of other gear boxes due to its special working conditions. The structure and transmission principle of a high-power marine gearbox are analyzed, and the experimental test is carried out for the analysis and calculation of its vibration characteristics and intensity. Measured by FFT analysis of vibration signals, the main peak is caused by its octave and the engagement frequency of input stage and middle-class transmission. The vibration severity of high-power marine gearbox reached 4.47 mm/s. In addition, the calculated structure noise of the measuring points is at the 1/3 octaves, and the largest structure noise is 131.27 dB which occurred in the frequency of 329 Hz.     

Development of Automobile Noise and Vibration Analysing System with Object Otiented Technology

With the developing of the automobile industry, how to control the noise and vibration level of the products come to urgently for the auto factories during their developing and producing period. Finding out the main noise source and vibration source quickly, analyzing the noise and vibration signal effectively, contriving a noise descending algorithm reasonable and economical become the first and most important job for auto corporations. At the mean time it complicate the developing guide line of the noise and vibration testing system. With object oriented technology, we can develop the noise and vibration testing system in a short time and with a low cost. The object oriented technology emphasizes the circulation, exoteric and expandable of the codes. It enables us developing the system follow a flexible, integrable and economical procedure..     

传递功率对行星齿轮传动系分岔特性的影响规律

针对行星齿轮减速器工作过程中传递功率的频繁变化容易导致其运动状态发生突变的问题,探讨行星齿轮传动系统随传递功率的分岔特性。基于2K-H型行星齿轮传动系统纯扭转非线性动力学模型,采用CPNF(continuous Poincaré-Newton-Floquet)方法研究了传递功率对行星齿轮传动系统周期运动稳定性的局部精细分岔规律,运用直接数值积分的方法绘制了系统随功率的全局分岔图,并对两种仿真结果进行了对比。结果发现,在某些参数组合下,行星齿轮传动系统会共存几个稳定或不稳定的周期轨道;当功率在196~220 kW范围内,随着功率值的逐渐增大,行星齿轮传动系统的各种形态的周期轨道均是通过倍周期倒分岔的途径在相应功率分岔点处发生稳定性突变的;在轻载工况下(传递小功率),行星齿轮非线性系统容易呈现混沌运动状态。     

Analysis of Low frequency Noise of Bridge Considering the Vibration of Bridge Deck

Under the dynamic load of vehicle, the bridge will vibrate and radiate low frequency noise which is harmful to human health. A method for predicting the low frequency noise is proposed based on the analysis of vibration of bridge deck. The prediction includes the analysis of vehicle bridge coupling vibration considering the bridge deck and the analysis of sound radiation and propagation in the air. By taking a bridge with low frequency noise as example, the vibration and sound radiation of the bridge are analyzed respectively by the current method and the previous method based on the grillage model. The results show that the prediction based on the vibration of bridge deck is more accurate. Furthermore, the measures to reduce the noise of bridge are explored, and the results indicate that a smoother road surface leads to lower noise. But when the condition of road surface is up to the extremely good standard defined by ISO, the effect of reducing the roughness of surface is not significant. Also, strengthening the crossbeam in the bridgehead is a simple and effective way to reduce the low frequency noise of bridge.     

Power Model of Bond Graph and Dynamic Simulation of Hoist System for Multi-Flow Transmission

The double drive hoist reducer developed in the planetary gear is a new generation of energy saving and environment protecting hoist product. The multi flow transmission system theory of hoist is analyzed. With the theory and method of bond graph,a bond graph model with coupled vibration is established for hoist multi flow transmission system for the first time. The state equation of the system is developed and dynamic simulation analysis is also carried out. The internal changing law and relationship of the system for the state variable are got. Therefore, the dynamic properties and gearing features of this system are revealed comprehensively. The research results can provide the dynamic analysis method and design basis for multi flow transmission system of hoist.     

Accelerated Vehicle Exterior Noise Control of Minicar SC6360B

This paper studyies the method of controlling SC6360B's accelerated vehicle Exterior noise. First, the main noise is found, which is from engine compartment and from exhaust noise by the identification of vehicle noise resource. Second, this paper carris out the farther noise identification experiment on engine and the insert-loss experiment on the exhaust gas muffler. In the end, the authors make sure that the noise is mainly infected by direct leaked noise from engine compartment, radiation-noise caused by the vibration of engine accessories and loud exhaust noise because the muffler has dficient elimination . The corresponding methods has been adopted according to the analysis. Through the test, the noise is lowered 2.5 dBA than it was and reach the new requirement.     

Research on Bridge Structure Noise of Railroads and Underground

This paper analyses the generating mechanism of radiation noise which produced by bridge structures and vibro-acoustic characteristics, and reviews the current situation of the researches on the relevant standards of structure noise at house and abroad. The author summarizes the method of measurement and calculation about structural noise at house and abroad, further notes their limits. This paper explores the impact of such factors as rain speed and other different fluids on structure noise. The noise characteristics of structures like cavity structure and thin-slab structure are also discussed. Strategies for reduce the bridge structure noise are summed up by reducing the vibration of track structure, altering the structure of boundary conditions, increasing the stiffness and changing the bridge cross section. Finally it comes to a conclusion that a combination of these strategies is the root way to settle the question of the bridge structure noise.     

Design and experimental validation of a novel double ring plate gear reducer

A novel double ring plate gear reducer (DRPGR) is designed and its experimental validation is conducted. By using the closed graph method, the modification coefficients of internal gearing in DRPGR are determined. Based on this, the overall structure of the reducer is designed and its kinematics simulation is achieved. With APDL programming language of ANSYS, a 3D finite element (FE) model of DRPGR is established, and its modal analysis and loaded tooth contact analysis (LTCA) are conducted respectively. The modal analysis reveals that the lower natural frequencies of DRPGR are much higher than the input frequency and the lower modes can be classified as vertical and horizontal bending of input and output shafts. The LTCA indicates that three pairs of gear teeth contact simultaneously at rated output torque. Due to the multi teeth contacts, the maximum stress is much lower than the permissible stress of internal gearings. The experimental tests of the prototype validate that DRPGR is adapted to both single driven and dual driven work condition. When single droved, DRPGR can eliminate the kinematic uncertainty by non 180 degree phase difference design. DRPGR claims a better dynamic performance in dual driven work condition. The efficiency of DRPGR increases with the increment of output torque and the reducer has an excellent short term overloaded capacity. The experimental results validate that the proposed method can be used to guide the design of that kind of reducer.     

Review of research on international gear transmissions

Several international conferences on gears is introduced, furthermore, the statistic analysis is conducted on the international gear research in recent years by taking example of the most influential Germany international gear conference. Some important issues on the design, manufacture, and application of gear transmissions is discussed including how to improve the load capacity, suppress vibration and noise, improve transmission efficiency, save resources, improve the efficiency of manufacture, and avoid the environmental contamination, and so on. Main progresses and research highlights of the international gear researches are also introduced and analyzed.     

Dynamic optimization design of marine gear transmission system

A dynamic model of transmission system for a marine gear is established considering time-varying mesh stiffness, mesh damping and tooth composite error. The solution efficiency is improved by taking contact line length change of gear pair instead of instantaneous gear mesh stiffness change and making mesh damping and tooth surface equivalent to viscous damping. Multi-objective dynamic optimization design is put into practice to improve the marine gear transmission system using vibration acceleration and mass as target function. The results show that the optimization method can effectively reduce the vibration level and mass of marine gear.     

Contact analysis of a new style planetary reducer with a double crank and internal gear board

To address the problems of low carrying capacity and short life of bearings in current ring reducers, a new type of ring reducer is proposed which consists of a two stepped transmission. One is a planetary transmission, and the other is an N type planetary transmission with a low tooth number difference. Based on the analysis of structural features, the transmission principle, and a transmission load situation, a contact finite element model of the new type of ring reducer is set up, and the stress value and the actual pairs of meshing teeth are derived by calculation. Based on gear modification research theory, the second stage transmission gear pairs of the new reducer are modified on its teeth profiles. Results demonstrate that the load capacity of transmission gear pairs have been enhanced greatly.     

Identifying Research on Noise Sources of Rotary Vane Compressor

This paper describes the noise mechanism of rotary vane compressor JSS -96 by the method of running independently, spectrum and the measurement of the sound intensity. The noise sources of this type compressor mainly include noise of electromotor, outlet noise and intake noise. Electromotor noise and outlet noise among them have most influence on the compressor noise. This is the further basis of noise control for rotary vane compressor.     

New Technology of Profile Grindng for Tow Teeth Difference Cyclodal Gear

Two teeth diffenence cyclodal gears are the key parts in cyclodal reducer. The plate abrasive wheel method which is widely used at home has very low precision and productivity. So it' s the common problem to be immediately solved. The profile grinding technology discussed in this paper has been proved by practical production to be an efficient and economical cycodal gear manufacturing method.     

Dynamic characteristics research of gear coupling rotor system in gas turbine

Taking the sliding bearing into account, the lateral vibration analysis models of two single rotor were built respectively using the transfer matrix method. The transmission matrix of herringbone gear coupled unit is derived. Using whole transfer matrix method, the lateral torsional coupling analysis model of herringbone gear rotor system is set up, and the vibration characteristics of gear rotor bearing system in gas turbine is analyzed. Through numerical calculation and anlysis, the eigenvalue of gear rotor system, the Logarithmic decrement and the critical speed are obtained. The result shows that the working speed of this gear rotor bearing system is far away from the critical speed, therefore the system is stable and safe.     

Experimental Research on Noise Reduction of Mini-car

By means of noise sources separation experiment of mini car and the surface acoustic intensity measurement of the engine, this paper finds that the main noise source of the mini car is the intake noise. According to the frequency spectrum analysis of the intake noise, the design frequency of the three cavity Helmholz intake silencer is determined. The results of the experiments show that the silencer, which is patented, has a remarkable effect, about 8 dB(A) decrement, on the noise reduction of the mini car.