公差值域的扩展及其应用

针对尺寸链计算中会出现上偏差小于下偏差，即负数公差这一现象，基于尺寸公差指允许尺寸的误差（变动）量，并依据负数与正数的本质区别在于它们具有相反意义的量，以及允许尺寸的误差量的相反意义量是补偿尺寸的误差量两个基本概念，对负数公差进行了解释；由此将公差的值域从正数扩展为任意数，也将误差补偿量及补偿范围纳入公差控制的范畴并使其实现了数字化描述，符合新一代GPS公差体系的要求. 对负数公差进行解释后，装配尺寸链中的公差与误差补偿量可实现同步计算，便于计算机辅助公差设计，也使概率法计算含补偿件的装配尺寸链的公差更加准确. 

Extension and Application of the Range of Tolerance

There is such phenomenon in the calculation of dimensional chains that upper deviations may be smaller than lower deviations (negative tolerance). The essential difference between positive and negative numbers is that the amounts they represent has opposite meanings and the opposite meaning amount of the allowable error amount of the dimensions is the error amount of compensate dimensions. Based on the two concepts and the allowable error amounts of the dimension of the tolerance dimensions, the explanation of the negative tolerance was given. Then the range of the tolerance was extended to any real number from the positive number, and the error compensation amounts and ranges were included in the category of tolerance control and described in a digitalized way, which met the requirement of the new generation of GPS tolerance system. The synchronous calculation of tolerances of dimensions and error compensation amounts in assembly dimensional chains can be realized when the explanation of the negative tolerance is given. This makes it more convenient to use computer assisting the design of tolerances, and it also makes the calculations of the tolerance of assembly dimensional chains with compensation components more precisely with the probabilistic method.