大尺寸渐开线齿圈精冲技术

针对大尺寸渐开线齿圈的结构特点,结合精冲工艺特征分析了精冲制齿工艺的技术难点,设计了精冲模具。为了满足精冲工艺过程所需的三向压应力,针对性地开发了凸起式反压板结构和窄边凹模结构。结合凸起式反压板结构和窄边凹模结构特点,开展了大尺寸渐开线齿圈零件数值模拟实验和精冲制齿工艺实验,并对所加工的零件进行了检测。采用精冲工艺加工的大尺寸渐开线齿圈剪切面无撕裂,齿部变形区材料在三向压应力作用下,发生了较大的塑性变形,产生了加工硬化,齿部硬度值有了很大提升,提高了齿部耐磨性。所加工的齿圈零件齿根部表面硬度可达384 HV,齿侧部表面硬度相对于齿根部较低,硬度最大处为344 HV。通过精冲加工的齿圈零件齿部具有较高的残余压应力,能够提高零件齿部的耐疲劳性能,有效地增加了零件的使用寿命。零件齿部切向残余压应力为290.4 MPa,轴向残余压应力为455.6 MPa。

Fine blanking technology on large-size involute ring gear

For the structural characteristics of large-size involute ring gears,combining the characteristics of fine blanking process,the technical difficulties of manufacturing technology for fine blanking gear were analyzed,and a fine blanking die was designed.Then,a convex reverse pressure plate structure and a narrow side die structure were specifically developed to fulfill the three-directional compressive stress required in the fine blanking process.Based on the structure characteristics of convex reverse pressure plate and narrow side die,the numerical simulation experiments of the large-size involute ring gear and the manufacturing experiments of fine blanking gear were carried out,and the processed parts were tested.The results show that the shear surface of large-size involute ring gear processed by fine blanking has no tearing,and under the action of three-directional compressive stress,the material in the deformation zone of tooth undergoes large plastic deformation resulting in work hardening to greatly improve the hardness and abrasion performance of teeth.The surface hardness of root for tooth of processed ring gear parts reaches 384 HV,and the surface hardness of tooth side is lower than that of tooth root with the maximum hardness of 344 HV.In addition,the teeth of ring gear parts have the higher residual compressive stress through fine blanking,which improves the fatigue resistance of teeth for part and effectively increases the service life of parts.Finally,the tangential residual compressive stress of teeth for part is 290.4 MPa,and the axial residual compressive stress is 455.6 MPa.