程补偿值与预紧拉力(1)按式( 2-31 )计算目标行程补偿值 t?。已知温度变化值△ t=2 ℃,丝杠的膨胀系数α= 6 11 10 ??m?/℃,滚珠丝杠螺母副的有效行程 uL =工作台行程+安全行程+2 ×余程+螺母长度=( 600+100+2 × 20+146 ) mm = 886mm 故 t?= 11△ t uL × -610 = 11× 2× 886 × -610 mm = 0.02mm (2)按式( 2-32 )计算滚珠丝杠的预拉伸力 tF 。已知滚珠丝杠螺纹底径 2d =34.3mm ,滚珠丝杠的温升变化值△ t=2 ℃,则 2 2 t2 F=1.81 td 1.81 2 34.3 N 4258.89N ? ???? 8)确定滚珠丝杠螺母副支承用轴承的规格型号(1)按式( 2-33 )计算轴承所承受的最大轴向载荷 Bmax F 。N FF B44 .5723 69 .2929 2 159 .4258 F2 1 amax t max??????(2)计算轴承的预紧力 BpF 。N FF B BP81 .1907 44 .5723 3 13 1 max????(3)计算轴承的当量轴向载荷 Bam F 。N FF BP B95 .3664 15 .1757 81 .1907 F m am?????(4)按式( 2-15 )计算轴承的基本额定动载荷 C。已知轴承的工作转速 n= mn =230r/min ,轴承所承受的当量轴向载荷 Bam F =3664.95N ,轴承的基本额定寿命 L=20000h 。轴承的径向载荷 rF 和轴向载荷 aF 分别为 N48 .1832 5.095 .3664 60 cos 0 am r???? BFFN5.3188 87 .095 .3664 60 sin FF 0 Bam a????
全文预览
