钳盘式制动器制动活塞异型密封性能研究

Research on Sealing Property of Brake Piston Special-shaped Seal of Clamp Disc Brake

提出将异型密封结构形式应用于汽车钳盘式制动器活塞的密封中,根据密封界面流体动力学中的弹性流体动压模型,建立制动液油膜的准一维流动的雷诺方程,给出制动活塞往复运动时的油膜厚度和泄漏量的计算方法。利用Fluent软件平台,对比分析制动活塞异型密封梅花形密封圈和标准型O形密封圈在往复运动过程中油膜厚度和制动液泄漏量受摩擦因数、制动压力、压缩量等因素影响规律。结果表明:梅花形密封圈和O形密封圈的油膜厚度随着摩擦因数的增大而增大,随着制动液压力和压缩量的增大而减小;但异型密封梅花形密封圈在相同的摩擦因素条件下有更好的润滑性能,泄漏量小,其油膜厚度相对于O形密封圈变化过程比较缓慢,降低了对密封圈的磨损;在压缩量较大的情况下,制动活塞梅花形密封圈的防泄漏能力大于传统的标准密封结构O形密封圈。制动活塞采用异型密封结构可有效减小密封圈的磨损量,有较好的防泄漏能力,能够实现良好的自密封。

The special-shaped sealing structure was applied to the seal of the piston of the automobile caliper disc brake.According to the elastic fluid dynamic pressure model in the fluid dynamics of the sealing interface,the quasi-one-dimensional flow Reynolds equation of the brake fluid oil film was obtained,and the calculation method was given about the oil film thickness and leakage amount when the brake piston reciprocates.Using Fluent software,the influence of factors such as friction coefficient,brake pressure and compression on the oil film thickness and brake fluid leakage were compared and analyzed during the reciprocating process of the brake piston special-shaped sealing quincunx-ring and the standard sealing O-ring.The results show that the oil film thickness of special-shaped sealing quincunx-ring and the O-ring sealing are increased with the increase of the friction coefficient,and decreased with the increase of the brake fluid pressure and the compression amount,but special-shaped sealing quincunx-ring has better lubricity and smaller leakage under the same friction conditions.The change of oil film thickness of special-shaped sealing quincunx-ring is relatively slow compared with the O-ring,which reduces the wear on the sealing ring.In the case of large compression,the anti-leakage capability of the brake piston special-shaped sealing is greater than that of the conventional standard sealing O-ring.The brake piston with a special-shaped sealing structure can effectively reduce the wear of the sealing ring,has good anti-leakage ability and can achieve good self-sealing.