Bback后背backconnected背后连接backcover后盖backgroundcontamination本底污染backgroundnosie本底噪声backlash齿侧间隙，游隙backplate底板backpressure背压backpressurecircuit背压回路backpressuresensor背压式传感backpressuretypesensor背压式传感backpressurevalve背压阀backsupportring背撑环back-to-backring背靠背密封圈back-to-backtest成对试验back-up支撑back-upring背撑环，挡圈back-uproll支撑辊backwash反流冲洗baffle隔板baffleplate隔板bafflering隔环bag皮囊bagaccumulator皮囊式蓄能器bagtypeaccumulator皮囊是蓄能器bagtypestrainer滤袋balance平衡balanceconnection补偿油口balancedpistontypereliefvalve平衡活塞式溢流阀balancedpressurevanepump平衡式叶片泵balancedratio平衡比balancedreliefvalve平衡式溢流阀balancedrotorvanepump平衡转子式叶片泵balancedseal平衡式密封balancedself-sealingcoupling平衡式自封接头balancedtypemechanicalseal平衡式机械密封balancedvalve平衡的阀balancedvanemotor平衡式叶片马达balancedvanepump平衡式叶片泵balancedimpactmodulator平衡冲流型元件balancedline补偿管路balancedpiston平衡活塞balancedratio平衡比balancedspring平衡弹簧balancedsystem平衡系统balancedtypecylinder平衡式缸balancedvalve平衡阀balanced（1）平衡（2）补偿balancedcircuit平衡回路balancedcylinder平衡缸balancedgroove平衡槽balancedpiston平衡活塞balancingvalve（1）平衡阀（2）等量分流阀ballcheckvalve球式单向阀ballelement动球式元件balljoint球铰ballpistonmotor球塞马达ballpistonpump球塞泵ballsleeve球面卡套balltypedevice动球式元件balltypedirectionalcontrolvalve球式换向阀ballvalve球阀bandedV-belt编结三角皮带band-passfilter带通滤波器bandpressurelevel频带声压级bandseal密封包带bandviscometer带状粘度计bandwidth频带宽度bangbangservomechanism时间最佳开关控制banjo铰接管接头banjojoint铰接管接头Barlowformula巴劳公式barrel（1）缸筒（2）缸体barrier-lessaccumulator非隔离式蓄能器base基座basemounting底座安装baseoil基油baseplate底板basequantity基本量basiccircuit基本回路basicity碱性basicneutralizationnumber碱性中和值basicnumber碱值basicsymbol基本符合basictypecylinder基本型缸basicpurification分批净化basictesting分批试验法bathtubcurve浴盆曲线Baumedegree波美度bayonetflange承插法兰bayonettypequickreleasecoupling卡口式快速接头beamdeflectionamplifier偏流型元件bearing轴承bearinglength导向长度bearingload轴承载荷bearingplate支承盘bearingring导向套bedding-in研配bellhousing钟形罩bellowphragm滚动隔膜bellowphragmcylinder滚动隔膜缸bellows波纹管bellowsboot波纹管防护罩bellowscylinder波纹管缸