Analysis And Research On Gear Face Arc Chamfering Process Of Reverse Idler In Passenger Vehicle Transmission

Passenger car transmission is a typical application of gear drive, one of the important function of which is using the reverse gear to realize the rotation direction change of the driving wheel. In the reverse gear mechanisms which use the sliding gears, it is generally chamfered on the sliding gear end face to make sure the gear shifting process smooth and steady. This study object of this thesis is the processing of the reverse idler arc gear face chamfering of a certain type of passenger car transmission, which aims to provide guidance for the processing of the arc chamfering. The following contents illustrate the main ideas of my research:based on the specific requirements of the chamfer structure and size and combined with the processing principle, cutting edge curve of cutters for chamfering and the related parameters of machine adjustment are determined; and then the simulation of chamfering processing is accomplished in the software; at last analyze the influence of different cutting parameters on cutting process.(1) In the first two chapters, at first, the current situation of gear face chamfer processing and finite element method (FEM) in metal cutting at home and abroad are analyzed to understand the research object on the macro. Chamfer cutting process is complex which involves the multi— disciplinary comprehensive, so related theories are the cornerstone of the thesis. And then study the finite element method for solving elastic plastic materials and the temperature field problems. Finally, establish the related finite element equations.(2)In the third chapter, analyze the specific requirements of the structure and size of the gear face chamfering, clear the processing principle, calculate the cutting edge curve, and calculate other related processing parameters. On this basis, the rotary motion of the cutter relative to the gear that belongs to the spinning processing technology of gear face chamfering is specially studied in this paper, which turns out to deduce the motion trajectory equations of the tool tip relative to the gear. The simulation experiment of the trajectories conducted using MATLAB software, and the simulation results show that, as long as with the reasonable tool design and accurate calculation of relevant parameters, this kind of pointed arch chamfer can be easily processed, which could help solve the practical problems and provide theoretical support for tool designing and adjustment of the machine tool parameters.(3) The content of the fourth chapter is about the treatment of the simulation technology of chamfering processing: the advantages and disadvantages of different constitutive models are analyzed to determine the Johnson—Cook model as the gear material constitutive model; the friction in chamfering process is analyzed to select coulomb friction model to simulate the contact between cutter and gear; the shear failure mode is chosen that considerate the geometric and physical criterion comprehensively as the chip separation criteria; and aiming at high strain rate and the large deformation problems in chamfering processing, the ALE mesh technology is utilized to improve the mesh quality and control the mesh distortion, which makes the calculating result more accurate.(4) In The fifth chapter. First, the modeling of the cutting tool and the gear are established with use of the 3D drawing software UG, and then imported it into ABAQUS. In analysis, the single factor experimental method is used. After the post treatment of calculation results, the first step is the analysis of the stress distribution on gear face chamfering during chamfering processing. With the increase of the cutting speed, cutting force increases at first and then decreases and the turning point appears at the speed of 4500r/min of the tool rotate, and the rising—ratio of tool temperature is higher than the gear. With the increase/rise of cutting depth, cutting force continues to increase, and the temperature change of the cutting tool and gear change is little which increases slightly in the range of 200℃. The influence of the feed per tooth increasing is that temperature of cutting force and cutting is increasing slowly. The chamfering simulation is simplified, but the simulation results can be explained by the metal cutting theory, it validated the reliability of the simulation.The research of the reverse idler gear face arc chamfering both helps solve the problems in practice, and provide some theoretical guidance for the chamfering tool designing, optimization of cutting parameters and the improvement of chamfering quality.