Papers by Keyword: Bevel Gear

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Authors: Jinn Jong Sheu, M.S. He
Abstract: The difficulty in forging of bevel gear with an outside diameter larger than 75mm is due to the high forming load requirement. In this paper, a new intuitive method for the punch and preform design of the bevel gear warm orbital forging is proposed to lower the forging load and improve the die filling. The geometry of the forged bevel gear are divided into characteristic features and mapped to the main dimensions of the preform design. The exact dimensions of the preform are determined utilizing constraints of the volume constancy and the section centroid balance. The surface of punch tip is designed using the section profile described by a Bezier curve with five control points which are related to the preform and the forged part geometry simultaneously. The forming process was analyzed via the FEM simulation. The die stress was also calculated to prevent die failure and improve tool life. A PXW-200 orbital forging press was adopted for the experimental tests of the proposed designs. The unfilled area at the teeth faces were examined via the laser scanner. The experimental results of the maximum unfilled distances were varied from 0.3 mm to 0.8mm depending on the different punch tip profile design. The predicted tooth profiles were in good agreement with the experimental measurements.
Authors: Dong Sheng Ji, Xin Yun Wang, Lei Deng, Ju Chen Xia
Abstract: The closed hot precision forging process of a bevel gear with large cone angle was studied. According to the structure features of the bevel gear, two types of relief forging processes were proposed. First, simulations based on thermal-mechanical coupling finite element model were performed with Deform3D. Then the corresponding experiments were conducted and the results perfectly matched the simulation results. The advantages and deficiencies of two processes were discussed and a reliable basis for selecting the optimal process was proposed.
Authors: Jacek Pacana
Abstract: The article presents the course of the calculations and conclusions from the analysis of a bevel gear motion transmission using FEM. The motion transmission graphs show the angular variation of the driven gear in the case of a driving pinion that rotates with a constant angular velocity. In contrary to the classical Tooth Contact Analysis, which is carried out on stiff bodies, FEM analysis includes deformations of mating gears. Thus, it brings more realistic information on dynamic behavior and noise characteristic of analyzed gear drive.
Authors: Qiong Liu, Dong Xiang Chen, Tai Yong Wang, Jin Wang Zhang, Dan Wang, Wei Tian
Abstract: Bevel gear is a complicated curved surface parts, the traditional measuring method of bevel gear is by three coordinates measuring instrument for related parameters measurement and there are problems such as reload, high cost and waste of time. In this paper, development of Bevel gear on-machine measurement system based on open CNC system so that the manufacturing and measuring of bevel gear on the same machine tools. This article mainly has studied on structure and function of the system, analyzed the method of pitch deviation and the tooth surface error of the bevel gear and developed bevel gear on-machine measurement system by combining the method of MATLAB with VC++ mixed programming.
Authors: Seong Kyun Cheong, Dong Sun Lee, Yong Soo Kang, Tae Kun Lee, Hyun Kyu Kim
Abstract: Shot peening generate compressive residual stress, which reduces repeatedly assessed tension stress and increase fatigue life. In this paper, the fatigue characteristics are evaluated according to shot peening condition for the real differential gear. The specimen is a straight bevel gear which transmits rotation of engine to running wheel and it is caburized. The bending fatigue test was done by the jig of our own making. The peening time was changed to find the best condition for the long fatigue life time. Fractography of specimen was analyzed by SEM to detect the location of initial crack. The experimental results show that the optimum peening condition is at 65m/s of shot ball speed and 8min of shot peening time. From the SEM image, the location of initial defect and direction of crack propagation were found
Authors: Jun Song Jin, Ju Chen Xia, Xin Yun Wang, Hua Liu
Abstract: The life of bevel gear dies is determined by its stress state mainly. During the forging, the die teeth fractured and the bottom corner cracked in a few times. Finite Element Analysis (FEA) was employed to investigate the reason of failure. The results show that the tip fracture and the bottom corner crack mainly resulted from excessive tensile stress. In accordance with the FEA results, the non-plane parting face was changed into plane parting face and the radius of bottom hole was enlarged. The FEA result proves that the modification can greatly reduce stress concentration and the application proves that the modification can effectively solve the premature failure of the die.
Authors: Bao Long Liu, Jie Hong, Da Yi Zhang, Yan Hong Ma
Abstract: In the presented paper, the failure mechanism of 12Cr2Ni4A minitype straight bevel gear was analyzed by means of both experimental characterizations and numerical simulation techniques. Fractography and simulation were conducted to find the failure mechanism. 3D finite element models (FEMs) of the driven gear with different structure parameters were constructed and used to simulate the inherent characteristic and stress field in the tooth root. Fractography indicated that teeth of the straight bevel driven gear failed because of high cycle fatigue (HCF). Simulation results showed no resonance but stress concentration in the tooth root. It was concluded that this failure occurred due to high cycle fatigue (HCF) and high stress concentration caused by small tooth root fillet radius.
Authors: Song Ping Chen, Yong Xian Li, Gui Bin Li, Jian Lin Wang
Abstract: In laparoscopic surgery, many problems are due to the poor degrees of freedom (DOF) of movement in controlling the forceps and laparoscopes. This paper proposes a new flexible laparoscopic forceps manipulator using synchronous belt drive mechanism, which consist of two miniaturized parts, synchronous belt drive mechanism enables independent bending procedure from-90° to 90° at the tip of forceps, and friction wheel mechanism which provides pivoting motion of forceps around incision hole on the abdomen. This mechanism is simple with high rigidity and can easily be miniaturized. The most remarkable characteristics of the prototype described in this paper are: 1) the casing diameter of the forceps is 5 mm; 2) with high rigidity and the repeatability positioning accuracy was 0.5o in bending motion; 3) pure mechanical structure with simple operation and low cost. This manipulator can solve the conflicts and blockings in laparoscopic surgery by switching back and forceps towards, meanwhile, it eliminates the surgical doctor’s fatigue and enhances the precision of surgery with higher effectiveness and safety as well.
Authors: Faluvegi Erzsebet, Mate Csaba Zoltan, Cristea Luciana
Abstract: This paper presents the mathematical model of the straight bevel gear flanks with octoid II teething which is measured with a coordinate measuring machine, type DEA Global Performance. The mathematical model is realized by theoretical equations which occur in the face gear. The experimental data, obtained by using the coordinate measuring machine, is analyzed and the compensation of the probe tip is calculated. The differences between the surfaces are determined.
Authors: Xiang Bian, Zong De Fang, Kun Qin, Lifei Lian, Bao Yu Zhang
Abstract: Usually the gear modification is a main measure to reduce the vibration and noise of the gears, but in view of the complexity of the gear modification, topology optimization method was used to optimize the structure of the gear. The minimum volume was set as the direct optimization goal. To achieve the target of reducing contact stress, tooth root bending stress and improving flexibility, the upper bound of the stress and lower bound of the flexibility were set appropriately, thus realizing multi-objective optimization indirectly. A method for converting topology result into parametric CAD model which can be modified was presented, by fitting the topology result with simple straight lines and arcs, the model can be smoothed automatically, after further regulating, the geometry reconstruction was finished. After topology optimization, the resulting structure and properties of the gear are consistent with cavity gear. While reducing the weight of the gear, the noise can be reduced and its life would be extended through increasing flexibility and reducing tooth root stress.
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