轮缘推进器水润滑聚晶金刚石推力轴承承载性能试验研究

Experimental Study of Load Carrying Performance of Water Lubricated PCD Thrust Bearings for Rim Driven Thrusters

为解决舰船轮缘推进器(RDT)水润滑推力轴承承载能力差、使用寿命短等问题,提出采用超硬材料聚晶金刚石(PCD)为摩擦副的重载水润滑推力轴承设计方案。研制了金刚石粒度分别为10μm,25μm和35μm的PCD推力轴承并开展了台架试验和RDT样机试验。台架试验结果表明,粒度为10μm的轴承在重载工况下的摩擦因数波动剧烈,而粒度为25μm和35μm的轴承在20 MPa比压下可以稳定工作。该比压比现有RDT采用常规软/硬材料配副的水润滑推力轴承比压提高了40倍。转速为400 r/min时轴承的稳定摩擦因数约为0.015,且在数十小时的试验中无磨损迹象。粒度为35μm的轴承通过了在RDT样机上开展的为期1个月的启停、加减速、高速重载等严苛工况下的试验考核,证明水润滑PCD推力轴承可以胜任RDT极端恶劣环境的工作。

In order to solve the problems of weak load carrying capacity and short service life of water lubricated thrust bearings of ship rim driven thrusters(RDTs),a heavy load bearing scheme was proposed using superhard polycrystalline diamond(PCD)as friction pairs.Several sets of PCD thrust bearings with diamond grain sizes of 10μm,25μm and 35μm were manufactured respectively.These bearings were tested on a bearing test bench and further on a RDT prototype.The results of the bench test show that friction coefficient of PCD thrust bearings with grain size of 10μm fluctuates violently under heavy load conditions,while the bearings with grain size of 25μm and 35μm may work stably under the specific pressure of 20 MPa.This specific pressure is 40 times higher than that of the water lubricated thrust bearings with conventional soft/hard materials matching pairs used in the existing RDTs.The stable friction coefficient is about 0.015 when the rotating speed is 400 r/min,and there is no sign of wear in tens of testing hours.The PCD bearings with grain size of 35μm passed the test assessment under harsh working conditions such as start and stop,acceleration and deceleration,high-speed and heavy load on the RDT prototype for one month.It is proved that PCD thrust bearings are competent for RDTs under heavy load conditions and extremely harsh working environments.