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1、第八第八 章章舵舵 机机Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slide
2、s for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.w第一节w舵的作用原理和对舵机的要求Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with A
3、spose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011
4、Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.8-1-1舵设备的组成和舵的类型w 舵用作为保持或改变航向 w 舵垂直安装在螺旋桨的后方n早期船舶采用平板舵n为了提高舵效和推进效率，目前多用由钢板焊接而成的空心 舵，称为复板舵l这种舵由于水平截面呈对称机翼形，故又称流线型舵 w 舵的型式很多，图81示出三种n舵叶的偏转由操舵装置(通常称舵机)来控制n舵机经舵柄1将扭矩传递到舵杆3上n舵杆3由舵承支承，它带动舵叶7偏转n舵承固定在船体上，由承及密封填料组成n舵叶还可通过舵销5支承在舵柱8的舵托9或舵钮6上Evaluation only.Eval
5、uation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.
6、2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.几种舵w不平衡舵图8-1(a) 舵杆轴线紧靠舵叶前缘的舵w平衡舵图81(b) 舵杆轴线位于舵叶前缘后面一定位置的舵w半平衡舵图81(c) 仅于下半部做成平衡型式的舵后两种舵在舵杆轴线之前有一定的舵叶面积，转舵时水流作用在它上面 产生的扭矩可以抵消一部分轴线后舵叶面积上的扭矩，从而减轻舵机的 负荷Evaluation o
7、nly.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Pr
8、ofile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.二、舵的作用原理和转舵扭矩w正舵位置，即=0时n舵叶两侧所受的水作用力相等，对船的运动方向不产生影响 w舵叶偏转任一角度 ，两侧水流如图所示n水流绕流舵叶时的流程在背水面就要比迎水面长，背水面的流速也就较迎水面大 ，而其上的静压力也就较迎水面要小n舵叶两侧所受水压力的合力(称为舵压力)FN就将垂直于舵叶
9、，作用于舵叶的压力中 心O，并指向舵叶的背水面n除FN外，水流对舵叶还会产生与舵叶中线方向一致的摩擦力Frn当舵叶偏转舵角后，在舵叶的压力中心O上，就会产生一个大小等于FN与Fr合力 的水作用F。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyrig
10、ht 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.舵水作用力及其对船的影响w F可分解为与水流方向垂直的升力FL和与水流方向平行的阻力
11、FD， FL=12CLA2 FD=12CDA2 x = Cxb 式中：CL，CD，Cx升力、阻力、压力中心系数，其大小随舵角而变，与舵叶 几何形状有关，由模型试验测定水的密度, A舵叶的单侧浸水面积，v舵叶处的水流速度J舵压力中心至舵导边距离, b舵叶平均宽度Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright
12、2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation
13、 only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client
14、Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.舵水作用力F对船舶运动的影响w 假设在船舶重心G处加上一对方向相反而数值均等于F 的力F1、F2 w 那么水作用力F对船体的作用n可用水作用力对船舶重心所产生的力矩Ms和F2的作用来代替 。n由F和F1形成的力矩Ms迫使船舶绕其重心向偏舵方向回转，称 为转船力矩：nF2则又可分解为R和T两个分力n纵
15、向分力R=F2sin，增加了船舶前进的阻力n横向分力T=F2cos ，使船向偏舵的相反方向漂移 w 水作用力F与船舶的重心G并不在同一水平面上n船在转向的同时，还存在着横倾与纵倾力矩Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004
16、-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.8-1-2-2 转船力矩与最大舵角w 转船力矩 (Ms)式中；l舵杆轴线至船舶重心的距离Xc舵压力中心至舵杆轴线的距离 w Ms随舵角的增大而增大，并在达到某一舵角时出现 极大值Mmax w Ms出现极大值时的舵角数值，与舵叶的几何形状有关 ，并主要取决于舵叶的展弦比 ( =舵叶高度A舵叶 平均宽度b)n越小, 绕流的影响就越大，即在同样舵角上所产生的
