Precise Shrink Fitting Design of the High Strength Gear Mold for the Precision Forging of Noncircular Spur Bevel Gears

Shrink fitting of forging mold (SFFM) is an effective method for improving mold strength, extending the mold’s service life and reducing the manufacturing cost of forging mold. However, due to the asymmetric geometry and complex stress distribution, the precise design of SFFM for the precision forging of noncircular bevel gears is very difficult. In this paper, a new precise design method of SFFM for the precision forging of noncircular bevel gears is proposed, which mainly includes the following five parts. First, a new design method for the mold parting surface—the curved surface parting method—is proposed to design the forging mold of noncircular spur bevel gears. Then, new dimension design methods for the gear mold and shrink rings based on the uniform shrinkage force are proposed. Third, a new design method for the inhomogeneous interference value between shrink rings and the gear mold is developed to provide a precise, uniform shrinkage force. After that, a strength correction method for the shrink-fitted gear mold is proposed to ensure the gear mold and shrink rings have sufficient strength both in the assembly process of the shrink-fitted gear mold and precision in the forging process of noncircular spur bevel gears. Ultimately, finite element simulations and verification experiments are performed to verify the proposed precise design method of SFFM for the precision forging of noncircular bevel gears. The precise design method of SFFM proposed in this paper is not only applicable to the precise design of the high-strength gear mold for noncircular bevel gears, but can also provide a valid reference for the precise design of the high-strength mold for other complicated asymmetric parts

Design and Simulation of Meshing Performance of Modified Straight Bevel Gears

As key components to transmit power and motion between intersecting shafts, it is necessary to design feasible tooth axial modification to improve the meshing performance and bearing capacity of straight bevel gears. The main purpose of this paper is to propose an effective axial modification method of straight bevel gears considering alignment errors. In this paper, the meshing performance of two kinds of tooth axial modification method (tooth end relief and symmetric crowned modification) for straight bevel gears is investigated by the finite element analysis (FEA). The results show that the tooth end relief is an optimal method to enhance the meshing performance of gears in different installations for decreasing transmission errors, reducing maximum contact stress and bending stress and improving the distribution of contact stress and bending stress. This research provides a suitable tooth end relief method of straight bevel gear with alignment errors.</jats:p

Deformation Characteristics and Microstructure Analysis of Aluminum Alloy Component with Complex Shape by Cold Orbital Forming

This work aimed to study the deformation characteristics and microstructure of AA6063 aluminum alloy component with complex shape manufactured by cold orbital forming processing. The material flowing behavior was analyzed by Finite Element (FE) simulation and forming experiments were carried out using bar blank with different lengths. The microstructure of the boss zone cut from the formed samples was observed using scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD). FE simulation and experiment results both showed the aluminum base can be formed using cold orbital forming process. The distributions of the effective strain of the component with different blank lengths were almost the same, and the effective strain was bigger at the boss and the flash as the forming finished. The material flow is complex, especially in the boss, and the folding defect was observed at the root of the boss. The distribution of Mg2Si strengthening precipitate is more homogeneous in the matrix, has a different shape, and shows directivity at different position of boss zone. The grains are elongated, and the extent is different at different positions of the boss zone after cold orbital forming, and the crystal orientation discrepancy is smaller in the component main body and bigger in the boss zone. Subsequent forming process and blank optimization need to be further researched to improve forming quality

Deformation Characteristics and Microstructure Analysis of Aluminum Alloy Component with Complex Shape by Cold Orbital Forming

This work aimed to study the deformation characteristics and microstructure of AA6063 aluminum alloy component with complex shape manufactured by cold orbital forming processing. The material flowing behavior was analyzed by Finite Element (FE) simulation and forming experiments were carried out using bar blank with different lengths. The microstructure of the boss zone cut from the formed samples was observed using scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD). FE simulation and experiment results both showed the aluminum base can be formed using cold orbital forming process. The distributions of the effective strain of the component with different blank lengths were almost the same, and the effective strain was bigger at the boss and the flash as the forming finished. The material flow is complex, especially in the boss, and the folding defect was observed at the root of the boss. The distribution of Mg2Si strengthening precipitate is more homogeneous in the matrix, has a different shape, and shows directivity at different position of boss zone. The grains are elongated, and the extent is different at different positions of the boss zone after cold orbital forming, and the crystal orientation discrepancy is smaller in the component main body and bigger in the boss zone. Subsequent forming process and blank optimization need to be further researched to improve forming quality.</jats:p

Static and Dynamic Analysis of a 6300 KN Cold Orbital Forging Machine

In cold orbital forging (COF) processes, large stress, displacement and vertical vibration of the COF machine are bad for the quality of the part and the fatigue life of the COF machine. It is necessary to investigate the static and dynamic performance of the COF machine and provide methods for reducing the stress, displacement and vertical vibration of the COF machine. In this paper, finite element analysis, theoretical analysis, numerical simulation and experimental analysis were applied to study the static and dynamic performance of a 6300 KN COF machine. The static and dynamic analyses were verified effectively by carrying out strain and vertical vibration test experiments. In the static analysis, the large stress and displacement positions of the COF machine were mainly distributed near the working table and the junction between the working table and the column. Large stress and displacement will be bad for the quality of the part and the fatigue life of the COF machine. Structural optimizations of the COF machine include ribbed plates on the working table and beam. This structural optimization method of the COF machine obviously reduced the stress and displacement of the COF machine. When the angular velocities of the eccentric rings were 8π rad/s, the vertical vibration of the swing shaft is a low-frequency vibration. The existence of absorber obviously reduced the vertical vibration of the COF machine.</jats:p