某船用唇形密封失效因素试验及仿真模拟研究

目的 针对船用唇形密封使用过程中的唇口破坏问题，研究唇形密封失效影响因素及唇形密封应力、位移、接触压力分布特性。方法 模拟实船齿轮箱输入结构搭建试验台，进行密封失效因素分析，并利用有限元分析软件建立旋转唇形密封的二维轴对称模型，分析过盈量及橡胶本体材料参数对唇形密封应力、位移、唇尖接触压力分布的影响。结果 除密封材料及密封接触应力因素不确定外，其他所列因素几乎均未发生泄漏，因此进一步对不同材料及接触特性进行有限元分析。研究表明，3种材料中，2号材料的Von Mises应力值最大，且不管何种材料，随着过盈量增加，唇尖应力沿着参考线先增大后、逐渐减小、再增大，并呈现非对称分布，过盈量超过0.4 mm时，唇形密封的最大应力出现在骨架与橡胶本体接触圆角处。随着过盈量的增加，3种材料唇尖最大接触压力的变化趋势不同，最大Von Mises 接触应力逐渐增大，且过盈量在0.6 mm之后增速较快，唇尖接触线位置接触压力先减小、后逐渐增大，拐点在接触线位置0.25~0.3 mm处。结论 油温、油压、安装方式、偏心量、转速对于唇形密封失效的影响较小。材料属性与过盈量都会引起唇形密封Von Mises应力及唇尖接触压力发生较大变化，只是影响应力峰值大小不同，材料属性对于唇形密封本体位移的影响较小，过盈量会引起位移较大变化，且会引起最大应力位置变化，同时接触线接触应力与接触压力大小没有相关性。对于唇形密封安装来说，在过盈量为0.8 mm左右时较为合理。

Experiment and Simulation on the Failure Factors of a Marine Lip Seal

The work aims to study the affecting factors of lip seal failure and the distribution characteristics of stress, displacement and contact pressure of lip seal, so as to solve the problem of lip breakage during the use of marine lip seal.A test bench was built to simulate the input structure of a real marine gear box to analyze the failure factors of the seal. A two-dimensional axisymmetric model of the rotary lip seal was established by finite element analysis software to analyze the effects of interference and rubber body material parameters on the stress distribution, displacement distribution and lip tip contact pressure distribution of the lip seal.Almost no leakage occurred under the factors except the uncertain factors such as sealing material and sealing contact stress. Therefore, the finite element analysis of different materials and contact characteristics was further carried out, and the study showed that the Von Mises stress value of No. 2 material was found to be the largest after calculation of the three materials, and for any kind of material, with the increase of the interference, the lip tip stress increased firstly along the reference line, then gradually decreased and then increased, and presented an asymmetric distribution. When the interference exceeded 0.4 mm, the maximum stress of the lip seal appeared at the rounded corner of the contact between the skeleton and the rubber body. With the increase of interference, the change trend of the maximum contact pressure at the lip tips of three materials was different and the maximum Von Mises contact stress gradually increased, the interference increased faster after 0.6 mm, and the contact pressure at the lip tip contact line firstly decreased and then gradually increased. The inflection point was between 0.25 mm and 0.3 mm at the position of the contact line.It is found that oil temperature, oil pressure, installation mode, eccentricity and rotating speed have little effect on the failure factors of lip seal. The Von Mises stress and the contact pressure of the lip tip of the lip seal will change greatly due to the material property and interference, but the peak value of the stress will be different. The displacement of the lip seal body will not be affected by the material property, but the interference will cause a large change in displacement and the maximum stress position, and there is no correlation between contact stress and contact pressure. For the installation of lip seal, it is reasonable when the interference is about 0.8 mm.