曲轴臂距差(俗称拐挡差、开挡差、甩挡差)是测量、检验曲轴不同轴度的一项指标。这项指标以与活塞行程成直线关系表示。这种表示虽不够严密,但由于这种表示较为简单,便于使用,有一定理论根据,故在曲轴新装、修理和运营中为世界各国所采用。国内在固定式和船用柴油机上也已制订了相应的规范。 Crankshaft arm distance difference (commonly known as poor turn block, open block, block block rejection) is measured, test crankshaft axis of an index. This indicator is in line with the piston stroke said. Although this expression is not rigorous, but because of this representation is simple and easy to use, there is a certain theoretical basis, it is the crankshaft in the new installation, repair and operation for the countries in the world. Domestic fixed and marine diesel engines have also developed the corresponding norms.