Driving Gear Research Articles

IC 센서를 이용한 고속철도차량 구동장치의 무선 온도 모니터링 시스템

Driving gear units can be affected by various problems, including those associated with external or internal defects in the bearing, problems with the lubricant oil, high-loading of the railway, and frequent impacts generated by rail joints. Temperature monitoring is a basic method in diagnosing abnormal conditions in the reduction gear and other components. This paper describes a new wireless monitoring system for the temperature diagnosis of abnormal conditions of the reduction gear. Integrated circuit (IC)-type temperature sensors were installed in the reduction gear box of a high-speed railway car. The temperature data from the reduction gear were acquired and analyzed in situ during high-speed rail operation. Analysis of these data was used to alert the driver and/or maintenance personnel when problems occurred.

Multiple-teeth defect localization in geared systems using filtered acoustic spectrogram

Contactless health monitoring of machines is highly desirable in industrial setups where the environment inherently imposes restrictions on contact-based data acquisition. This motivates the use of acoustic signal as an effective alternative for condition monitoring of equipments located in such inaccessible environments. However, condition monitoring and fault diagnosis by processing acoustic signals still remains a challenge for researchers. The aim of the proposed work is to establish a robust technique of acoustic signal processing for detection and localization of multiple teeth defect in geared systems. Towards this, the present work proposes the use of time marginal integration (TMI) of the continuous wavelet transform (CWT) coefficients of the decomposed signal derived from an undecimated wavelet transform (UWT) of the raw acoustic signal. UWT, owing to its well established translation invariant property, is implemented on the raw data to extract the de-noised signal for further processing with CWT. The time-axis of the TMI graph is finally correlated to the angular displacement of the driver gear in order to locate the defective teeth and measure their relative positions. An artificial neural network (ANN) model using signal statistical parameters as neurons is proposed as a pre-check to identify the presence of any defect in the gears. In addition, the efficiency of UWT as a de-noising tool is reestablished through the accuracy improvement in ANN based identification. A synthetic signal is simulated to conceptualize and evaluate the effectiveness of the proposed method. Synthetic signal analysis also offers vital clues about the suitability of the biorthogonal 3.1 wavelet over Daubechies and Symlet wavelets in the proposed algorithm. The experimental validation of the proposed method is presented using a customized gear drive test setup by introducing gears with seeded defects in one or more of their teeth. Measurement of the angles between two or more damaged teeth with a high level of accuracy is shown to be possible using the proposed algorithm. Experiments reveal that acoustic signal analysis can be used as a suitable contactless alternative for precise gear defect identification and gear health monitoring.

Gear fault identification and localization using analytic wavelet transform of vibration signal

The aim of this present work is to identify and localize the defect in gear and measure the angle between two damaged teeth in the time domain of the vibration signal. The vibration signals are captured from the experiments and the burst in the vibration signal is focused in the analysis. The enveloping technique is revisited for defect identification but is found unsatisfactory in measuring the angle between two faulty teeth. A signal processing scheme is proposed to filter the noise and to measure the angle between two damaged teeth. The proposed technique consists of undecimated wavelet transform (UWT), which is used to denoise the signal. The analytic wavelet transform (AWT) has been implemented on approximation signal followed by a time marginal integration (TMI) of the AWT scalogram. The TMI graph time-axis is mapped onto the angular displacement of the driver gear. The measurement is shown to identify the first and the second defective teeth impact on gear meshing, which is visible as sharp spikes in the TMI graph. An attempt is also made to replace the approximation from UWT with Intrinsic Mode Function (IMF) derived from the Empirical Mode Decomposition (EMD). The present experimental work establishes the proposed method of measuring and localizing multiple gear teeth defect using vibration signal in the time domain.

Study on Precision Forging Schemes of Hypoid Driving Gear

By analyzing the characteristics and forming technology of hypoid driving gear, it was suitable for adopting fully enclosed die forging principle to form the gear. Based on different forging methods, three kinds of blank shape and corresponding forming schemes were designed. The three dimensional models of blank and die were created by the UG software. The three forming schemes were simulated by the Deform-3D software. The simulation results of distribution of equivalent stress, distribution of equivalent strain and load-stroke curve were comparatively analyzed. Then the most reasonable scheme was chosen. At last, the rationality of numerical simulation can be further verified by the optimized scheme was proved by experiment.

全方向駆動歯車機構の研究

全方向駆動歯車機構の研究

Optimization Design in the Driving Gear Wheel Axle of Triangular Rubber Track Conversion

The heavy triangular rubber track conversion for the construction machinery has existed the disadvantage for weight oversized. The effective reduced triangular rubber track conversion's weight is essential in the engineering design. This article established one kind of triangular rubber track conversion driving gear wheel axle's three-dimensional model, integrated dynamics analysis has carried on the finite element analysis to it, based on this and carried on the size using Ansys Workbench to optimize for its most superior structure size, finally to optimized the result to carry on the finite element analysis once more. The result contrast indicated that at maintains under the wheel axle stress level basic invariable premise, after the optimized wheel axle weight reduces greatly, enhanced track wheel's performance effectively.

Friction and wear behaviour of acetal and nylon gears

The current paper will present an extensive investigation of polymer gear (acetal and nylon) friction and wear behaviour. First, a unique test method for polymer gear wear will be described in brief and later used in the extensive investigation of acetal and nylon gear wear. Initial tests were performed using acetal pinions with acetal gears, and nylon pinions with nylon gears, with further investigation carried out using dissimilar polymer gears. In this case the driver and driven effects on the gear wear behaviour was also considered when dissimilar materials were used. For acetal against acetal gears, it was found that the acetal gear wear rate increased dramatically when the load reached a critical value for a specific geometry and the gear surface showed slow wear, with a low specific wear rate if the gear was loaded below this critical value. It was found that the surface temperature was the dominant factor influencing the wear rate and an initial relationship between gear surface temperature and gear load capacity has been established and further developed. Experimental investigation on nylon gears was also carried out and different failures have been found compared to acetal gears, such as gear root and pitch fractures. The most interesting observation from the experimental work is the significant difference in wear behaviour when running acteal against nylon gears, especially the low wear rate when acetal is used as the driver gear.

Thrust and slip of a track determined by the compression–sliding approach

Driving gear of a vehicle (here a track) generates thrust as a reaction to the opposite force taken by the ground. This force causes rearward soil deformation, which is associated with vehicle slippage. The presented compression–sliding (CS) approach, based on field measurements with the original double plate (DP) meter, states that the soil deformation as a consequence to the increasing thrust occurs in two principal stages: (a) primary horizontal soil compression, which steadily increases towards the back of the contact length forming virtual soil segments among neighboring grousers and (b) secondary slide of these sheared off segments referred to as soil blocks, which may collapse under specific conditions. These two stages are separated by a transient situation when both the compression and sliding occur simultaneously. The respective compression–sliding (CS) approach enables to analyze the effect of track arrangement, design and loading on its thrust–slip characteristics. The paper also deals with situation of the existing shear plane theory in view of the CS approach and finally suggests a practical thrust–slip function complying with the CS logic.

Numerical simulation of conjugate spur gear action

This paper describes a finite element procedure which simulates the conjugate action of spur gear drives, by approximating both the rotations of gears and the elastic deformations of the load carrying teeth. Drive members are considered as individual subdomains, being able to rotate around corresponding axes, allowing elastic engagements at successive contact points. Discretizing gear motion by imposing incremental rotations on the driver gear, one establishes rolling contact between operating teeth surfaces. The load transmission occurred by the contacting surfaces arises variable elastic deformations which are being evaluated through finite element analysis. Accounting on standard proportions of gears and transmission characteristics of drives, the proposed model formulates a computational design problem by means of a few linearly independent global variables. Considering the necessary cases, the numerical efficiency of the method was examined and time histories of some significant stress components are presented and discussed. The proposed model describes effectively both the tooth loading conditions and the variation of stresses, and constitutes further a potent tool in analyzing gear drives.

Pressure transients in an external gear hydraulic pump

A measurement technique, that extends and integrates former experimental activities, has been developed to detect the variation with time of tooth space pressure in an external gear pump by use of a pressure transducer fi tted in the driver gear. The pressure signal from the miniature strain gauge sensor mounted in the bottom of the tooth space is taken out via slip-rings for acquisition and analysis. Angular phase is determined by an optical encoder connected to -the driven gear. The specific location of the sensor was selected to acquire a better insight and understanding of typical phenomena occurring within an external gear unit in operation.Results of the investigations may lead to a more thorough treatment of aspects improperly described in the mathematical model and support interventions on the geometry features of the pump aimed at better performance and lower radiated noise from these units.

Studies on Effects of Tip Relief upon Load Carrying Characteristics of Spur Gears : Mainly on Limiting Load for Scoring and Friction Loss

The effects of tip relief on the load carrying characteristics of spur gears were studied by means of FZG-Spur gear testing machine. Two kinds of tooth profiles were used for our studies. One was a nearly standard gear with almost no profile shifting, the other was a gear with a large profile shifting. In the case of the standard gear or the gear with profile of a small profile shifting, the load carrying characteristics were very good, if the tip relief was applied to both the driver gear and the follower gear, but it was unfavorable for the load carrying characteristics, if the tip relief was applied only to the driver gear. Furthermore the influences of tip relief in the case of profile shifted gears upon the load carrying characteristics were studied. The results with profile shifted gears were different from the results with standard gears.

Improved Frictional Driving Gear

Improved Frictional Driving Gear