曲柄滑块机构运动分析与力学计算一、运动分析)2cos(cos2sin21sin2sin241sin)2cos1(41)cos1()2cos1(41)cos1()2cos1(41)cos1()2cos1(411cos)2cos1(21sinsin211sin1sin1cos)2.0~08.0(sinsinsinsinsin)cos1()cos1(coscos222222222RdtdddVdtdVaRRdtdddSdtdSVRRLRLRSLRLRRLLRLRLRS.)(;)(),,,()2sin2(sin0)2sin2(sin)2sin2(sincossinsin1sinsincoscossin)sin()sin(sincos11221111进行计算设计时扭矩要照此要求角公称压力设计行程公称压力设计在下死点ggABABABABSLRPMPRRPMRPMRmmPMPP二、曲轴扭矩理论计算转动副的摩擦(轴颈摩擦)QN212121FNR力分析002121RMQRd221221221211fNFNR2121rFR全反力021rFMd或rfrffRrFv221211以轴颈中心为圆心,为半径作的圆称为摩擦圆,为摩擦圆半径。Md12QO12R21F21N21sin22)sin()(sin02000222'RRRPMRPRPRPRRmmPMLRRAABABABABAABBAPPPPPPABABAB很小,由于在下死点附近,coscos)90sin()90sin(三、实际机构扭矩计算理想机构:不计弹性变形;不计配合间隙不计摩擦;不计惯性力fgggPACggBABAfBABAAAmRPMPPMRRRRPMMMRRRmRRRPLRLRRRRRPRRRP2sin2sin,12sin2sin11MsinM00021002002公称压力行程公称压力;在下死点附近---摩擦力臂,当按压力行程计算扭矩作活塞允许载荷曲线,在任何情况下fpacpacfmRMPMmRP2sin2sin2sin2sin四、连杆的校验cABBABABABcABBABWXPRPFPWMFPXPRPMsincoscossin压弯组合