Design and friction loss study of full-ocean depth oil-filled direct current motor

Abstract

In this study, we designed an oil-filled motor that can be used at full-ocean depths, and investigated the friction losses caused by the rotating seal and the properties of the oil. The direct current (DC) motor is encapsulated in an aluminum alloy housing. A rubber diaphragm is used to balance the internal and external pressures so that the motor can work on the seabed without pressure difference. To study the resistance caused by the rotating seal, a numerical model of the Glyd ring and the rotating shaft was established. Results from a rotational torque test agreed with those from numerical analysis. The kinematic viscosity of four oils was measured at 1–25 °C. Oil bath experiments in an incubator showed that the resistance from oil is highly correlated with its dynamic viscosity. Dimethicone appears to be very suitable as an insulating oil for these motors. The working characteristics of the motor were tested in a high-pressure chamber. The results showed that the motor needs to overcome higher oil resistance under higher pressure. A prototype of a pressure-adaptive motor was designed and applied successfully in the hadal zone at a water depth of more than 10000 m.

摘要

目的

设计一种压力自平衡式充油电机以适应全海深工作的需求, 并探究输出轴处旋转密封件的摩擦阻以及四种不同类型油的粘性阻力, 为深海电动执行器的设计提供参考。

创新点

1. 提出了旋转密封用格莱圈对电机输出轴旋转阻力的影响。2. 通过仿真与实验相结合的方法探究了几种不同的液压油在不同温度下电机的粘性阻力影响。

方法

1. 在分析对比磁耦合电机与充油电机的基础上, 设计充油电机的结构(图1), 并介绍其控制方式和工作模式(图2)。2. 从两个方面研究充油电机的摩擦损耗特性: 首先, 研究旋转密封对电机的摩擦损耗, 在有限元分析软件Abaqus中建立分析模型(图3), 得到不同压缩率下的旋转密封接触压力分布(图4), 并搭建旋转密封测试平台以验证分析结果(图5); 其次, 研究充油类型在高压和低温情况下对充油电机工作的影响。3. 基于Fluent建立充油电机旋转分析模型, 并得到其在不同温度、不同油类型下的油粘损耗(图8)。4. 在高压舱内进行测试, 研究高压对电机工作性能的影响(图10)。5. 介绍所研制的电机在马里亚纳海沟的应用(图14)。

结论

1. 旋转密封格莱圈对于电机的摩擦阻力随着压缩率的增大而增大, 并且其启动阻力约为稳定运行时阻力的2.5倍。2. 电机所受到的粘性阻力与油的动力粘度高度正相关。3. 二甲基硅油是充油电机用油的合适选择之一; 其粘性阻力低且在低温下的动力粘度变化不大。