Abstract:

According to structural and loading characteristics of ram of heavy-duty CNC boring and milling machine,a new compensation method for the deflection of the ram with combined pull and push rods was proposed. Based on eccentric compression(or tensile) theory,two group of rods which provided opposite direction forces were installed inside of the ram.One group was the pull rods installed on the top side of the ram,another group was the push rods installed on the bottom side of the ram.Two group of pull and push rods were arranged with up and down,left and right symmetry about the spindle centerline,which form the two-way force groups.The axial pitch of two push rods and two pull rods were equal in size and opposite
in direction,so there were no additional deformation in axial direction.Compared with the traditional compensation method with pull rods,the compensation forces were provided by two tension cylinders and two thrust cylinders,so in the situation of same compensation degree,only a smaller cylinder pressure needed to be provided.The advantages of this compensation method were verified by theoretical analysis and finite element simulation.

Key words: heavy machine, ram, deflection, compensation, push rod

摘要：

针对重型数控落地铣镗床的滑枕结构及受力特点,提出一种新型的滑枕挠曲变形补偿方法——拉杆与推杆组合式补偿法。依据偏心压缩(拉伸)理论,在滑枕内部设置两组作用力方向相反的杆件：一组为置于滑枕上半侧的拉杆,另一组为置于滑枕下半侧的推杆。两根拉杆和两根推杆沿主轴中心线呈左右和上下对称布置,形成双向作用力组。由于拉杆与推杆在滑枕轴向的作用效果相互抵消,该方法在补偿滑枕的挠曲变形时不会产生附加的轴向变形。与传统的拉杆补偿法相比,该方法采用拉力和推力两组油缸提供补偿挠曲变形的驱动力,在补偿相同挠度的情况下,油缸所需提供的压力较小。通过理论分析与有限元仿真对该方法的优点进行了验证。
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关键词: 重型机床, 滑枕, 挠曲变形, 补偿, 推杆