轮机英语unit26-steering-gear课件.ppt

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1、Lesson26SteeringgearThedirectionoftheshipiscontrolledbythesteeringgear.Astheshipmovesthroughthewater,tileangleoftherudder(舵叶）atthestem（舵柱）determinesthedirectionitwillmove.Modernshiparesobigthatmovingtheruddernecessitatestheuseofhydraulicsorelectricalpower.Thesteeringgearprovidesamov

2、ementoftherudder（舵）inresponsetoasignal（信号）fromthebridge（驾驶台）.Thetotalsystemmaybeconsideredmadeupofthreeparts:controlequipment（控制设备）,apowerunit（动力单元）andatransmissiontotherudderstock（转舵机构）.Thecontrolequipmentconveysasignalofdesiredrudderangle（期望舵角）fromthebridgeandactivates（触发）thepoweru

3、nitandtransmissionsystemuntilthedesiredangleisreached.Thepowerunitprovidestheforce,whenrequiredandwithimmediateeffect,tomovetheruddertothedesiredangle.Thetransmissionsystemismeansbywhichthemovementoftherudderisaccomplished.Thesteering（操舵)startsatthebridge.therequiredrudderangleistran

4、smittedhydraulicallyorelectricallyfromthesteeringwheelatthebridgetothetelemotor(液压传动操舵装置）atthesteeringgear,justabovetherudder.Thereareafewcommonarrangementsforusinghydraulicpower.Thereare4-rams（撞杆）,2-rams(fig.26-1)androtaryvanetypes（转叶式）.Theheartofthesehydraulicsystemsisthevariablede

5、liverypump（变量泵）.Thistypeofpumpcanbecontrolledbyjustmovingaspindle（控制杆）.Thepumpisdrivenbyanelectricalmotoratconstantspeed.Bymovingthecontrolspindleawayfromthecentralpoint,thepumpstrokeincreases,andthehydraulicfluidispumpedinonedirection.Movingthespindlemorefromthecentralpointwillcause

6、morefluidtobepumpedandconsequentlymorepressuregeneratedtodrivetherams（撞杆）.Movingthecontrolspindlebacktotheoriginalpositionandthenawayintheoppositedirectioncausesthehydraulicfluidtobepumpedinthereverseddirection.Theramswillalsomoveinthereverseddirection.Byusingafloatinglever（浮动杆）feedb

7、ackmechanism（反馈机构）,whentherudderstock（舵柱）hasreachedthedesiredangle,thepumpcontrollevermovesbacktotheoriginalposition,andthepumpingactionstops.Therudderisstoppedattherequiredangle.Movingthesteeringwheeltotheoppositedirectionwillcausetheruddertocomebacktotheoriginalzeroposition.Certain

8、requirements