Analysis of axial force of double circular arc helical gear hydraulic pump and design of its balancing device

In view of the axial force produced in the working process of double arc helical gear hydraulic pump,the theory of differential equation of curve and curved surface was utilized so that the calculation formula of axial force was obtained and the relationship between the axial force and structure parameters of gears was clarified.In order to balance the axial force,the pressure oil in the high pressure area was introduced into the end face of the plunger to press the plunger against the gear shaft,and the hydrostatic bearing whose type is plunger at the end of the shaft was designed.In order to verify the balance effect of axial force,the leakage owing to end clearance and volume efficiency of gear hydraulic pump before and after the balancing process was analyzed.This paper provides a new analysis idea and balance scheme for the axial force produced in the working process of the double arc helical gear hydraulic pump,which can reduce the leakage owing to end clearance caused by the axial force and improve the volume efficiency of the gear hydraulic pump.

电镀金刚石线锯氨基磺酸盐预镀镍工艺

采用由500 g/L Ni(NH2SO3)2·4H2O、30 g/L H3BO3和30 g/L NiCl2·6H2O组成的镀液对高碳钢丝预镀镍,以制作晶体硅太阳能电池片切割用电镀金刚石线锯.研究了镀液pH、温度和电流密度对预镀镍层表面形貌、结合力和抗拉强度的影响.得到较优的预镀工艺条件为:pH 4.5,温度55℃,电流密度3.5 A/dm^2.该条件下所得预镀镍层细致、平整,与母线结合良好,抗拉强度达3403.5 MPa.

管程流体诱导锥螺旋管束振动的实验研究

为了研究换热器内锥螺旋管束在管程流体诱导下的振动特性,搭建了管束振动测试实验台,在管程流速为0.106~0.446 m/s的范围内,利用加速度传感器实测了管束的振动加速度,分析了管束的振动加速度频谱图和振动位移幅值的变化。实验结果表明:在管程流体的作用下,流速为0.106~0.361 m/s时各排管束的振动主频不变,流速继续增大时主频改变;管束振动主频的加速度幅值随流速增加整体上呈现先增大后减小的趋势;管程流体对顶排管束振动的影响最大,自上而下对管束的激励作用逐渐减小。