Papers by Keyword: Bevel Gear

Abstract: In the article the model for forecasting of thermal processes arising during processing of bevel gears is presented. The kinematics of cutting is modeled due to the analytical model. Chipping is modeled using the finite element method. The experiment is based on the method of infrared photography of the cutting process. In the process of carrying out a numerical experiment, the graphs of the heat fields for the tool, the workpiece gear and chips were obtained, and an array of data on their change during the cutting process was achieved. The simulation results showed that the maximum temperatures and heat flows in the tool depend significantly on the choice of the rake and clearance angels of the cutting.

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.

Abstract: Normal circular-arc spiral bevel gear is a new type gear based on Bertrand conjugation principle. Normal circular-arc bevel gear selects directrix on the basis of paying attention to machining planning process. When the directrix serves as loxodrome, the formed tooth profile surface not only has fine transmissibility like general arc bevel gear, but also is convenient to machining. Starting with differential geometry, the geometry nature and inner relationship of Bertrand conjugation surface are studied. Then the normal circular-arc surface id put forward which is a typical Bertrand surface; the conjugation theory of loxodrome normal circular-arc bevel gears is studied. The characters of loxodrome line are analyzed. The tooth profile of loxodrome normal circular-arc bevel gears, the primary condition the directrix line must be satisfied, the relative curvature of the conjugating surfaces, the relations between non-interventional condition and curvature axle of the directrix line is provided; the NC machining theory of normal circular-arc bevel gears is studied, including the designing and manufacture of the tool, the movement of the machine, the adjustment of the tool under the condition of tangency and non-interventional condition and so on.

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.

Abstract: One of the main problems with the operation of spiral bevel gears is related to very severe conditions in the contact of the meshing teeth; therefore, lubrication is very difficult, which increases the risk of scuffing occurrence. One of the ways to achieve better scuffing resistance is by the deposition of a low-friction coating on the bevel gears teeth. Gear scuffing tests were performed using a bevel gear test rig designed and manufactured at ITeE-PIB. The authorial bevel gear scuffing test was performed. Specially designed, spiral bevel gears were used for testing. Two material combinations were tested: uncoated pinion - coated wheel and, for reference, both gears without coatings. The a-C:H:W (trade name WC/C) coating of DLC type was deposited on the wheel teeth. A mineral, automotive gear oil of API GL-5 performance level was used for lubrication. It is shown that the resistance to scuffing may be significantly improved when the a-C:H:W coating is deposited on the spiral bevel gear teeth.

Abstract: The finished and preformed forgings of the rear lower arm are shown respectively, the shape of the rear lower arm is very complex.The tops of three branch arms are thick lumps and its central part consits of quite thin ribs.This forging is much more slender than the ordinary weldment made of steel plate and its weight is also lightened enormously.It seems that the forging is a limit example of pursuing the weight reduction.By taking great pains in forging scheme and die design,the forging is a success eventually.Simulation results indicate that the essential reason to form lap is the return when the material contacts the ends and the non-symmetrical return intensifies the depth of the lap.The lap was formed at the last moment.According to the simulation results, the dies was ameliorated. Thus,the qualified forging has been obtained eventually.

Abstract: The overview and analysis of the structure of spiral bevel gear transmission system was presented . The characteristics of transmission and torque of the system were analysis and calculated . Based on high-speed trains operating conditions. The issue that tooth contact of the positive invertion of spiral bevel gear was analysis. The consistency of the positive invertion was desirable. The error curve of the transmission was downward consistently and the curves which were adjacent intersect. The less of the vibration of bridge contacts won`t be happened.

Abstract: This study applies the finite element method (FEM) to predict maximum forging load and effective strain in bevel gear forging. Maximum forging load and effective strain are determined for different process parameters, such as modules, number of teeth, and die temperature of the bevel gear forging, using the FEM. Finally, the prediction of the power requirement for the bevel gear warm forging is determined.

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.

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.