采用海水润滑的艉轴,为避免轴体的腐蚀,以延长艉轴的使用寿命,一般在艉轴上红套黄铜或青铜的铜套。由于下列原因,红套过盈量不宜也无须过大:其一,目前采用水润滑的轴承(如铁梨木、层压板、尼龙轴承,及金属-橡皮轴承等)的内径与铜套的外径间均设有一定间隙以流通足够的水量来保证轴承的良好润滑和冷却性能。其二,若过盈量过大时,铜套内表面的应力太大,因而必须加厚铜套,加大轴承及尾管等部件的外径,这样必然会增加轴承的重量。其三,采用过大的过盈量,为了套入铜套,必须提高加热温度,动用更多的设备。然而,也不宜采用过小的过盈量: Sealed with the shaft of the sea, in order to avoid the corrosion of the shaft to extend the service life of the shaft, usually in the shaft on the brass sleeve or bronze copper sleeve. Due to the following reasons, the amount of red envelope interference should not be too large: First, the current use of water lubricated bearings (such as iron pear wood, laminate, nylon bearings, and metal - rubber bearings, etc.) Between have a certain gap in order to circulate enough water to ensure good bearing lubrication and cooling performance. Second, if the interference is too large, the copper sleeve inner surface of the stress is too large, and therefore must be thickened copper sleeve, increase the bearing and tail pipe and other components of the outer diameter, this will inevitably increase the bearing weight. Third, the use of excessive interference, in order to set into the copper sleeve, you must increase the heating temperature, the use of more equipment. However, it should not be used too small amount of interference: