空间伺服机构装配过程中轴承预紧力的控制

Control of bearing preload during assembly of space servomechanism

通过改变预紧力将产品化轴承适应性地应用于不同类型载荷伺服机构,对降低产品研发成本、提高产品继承性有着极大助益。本文根据启动摩擦力矩和预紧力的关系,识别出轴端压紧力和过盈摩擦力是轴承装配过程预紧力控制的两项主要影响因素,并给出了具体数学关系。将轴承过盈配合简化为组合厚壁圆筒模型,得到了过盈摩擦力计算方程。进一步地,依据虎克定律和杨氏模量定义,推导了轴承压装过程中轴端压紧力与轴承预紧力的数学关系,并在上述基础上,提出了空间伺服机构装配过程轴承预紧力控制方法。最后,依托某工程型号伺服机构,进行了预紧力控制和轴承寿命实验研究。预紧力控制实验结果显示,所述方法能够有效实现轴承预紧力的控制,间隙配合、过盈配合理论与实验误差分别为2.6%,20.3%;轴承寿命实验结果显示,采用所述方法装配后的轴承寿命末期回转倾角误差为3.04″,摩擦力矩为25.8 mN·m,满足该工程型号空间伺服机构的使用需求。

Productized bearings can be applied to servomechanisms in space with different loads by adjusting the bearing preload,and this can helps reduce cost and improve succession.Firstly,in accordance with the relationship between preload and friction torque,the factors influencing preload in the bearing assembling process were identified and an equation was developed.Subsequently,the bearing′s interference fit was simplified to a thick-walled-cylinder model and the relevant equations were deduced.Further,based on Hooke′s Law and the definition of Young′s Modulus,the mathematical relationship between the bearing preload and force loaded on the shaft end was deduced.Based on the above steps,a method to control the bearing preload during assembly was proposed.Finally,experiments were conducted to evaluate the control method,with support from a satellite project fund.The results of the experiments indicate that the proposed method can control the bearing preload well.Errors corresponding to the clearance-fit and interference-fit conditions are 2.6%and 20.3%,respectively.Furthermore,towards the end of their lives,the angular-error motion and friction torque of the bearings assembled using the proposed method are 3.04″and 25.8 mN·m,respectively,and these values satisfy the usage conditions of space servomechanisms installed in satellites.