极限、公差与配合(Limits, Tolerances, and Fits)

渔樵

极限、公差与配合(Limits, Tolerances, and Fits)
7 h: p2 U  c* u& fMachine parts are manufactured so they are interchangeable. In other words, each pert of a machine or mechanism is made to a certain size and shape so it will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way.
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Limits. Limits are the maximum and minimum values prescribed for a specific dimension. For instance, if the nominal diameter of a hole is 1 in., and the limits of size are expressed as 0.999/1.001 then any work not over 1.001 in. nor under 0.999 in. will be accepted.
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Tolerance. The difference between upper and lower limits is called the tolerance. With a maximum limit of 1.001 in. and a minimum limit of 0.999 in., the tolerance would be 0.002 in. Tolerances may be shown on drawings by several different methods.
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: _3 u% L7 t. V( \Allowance. Allowance applies particularly to fits, as in the case or a hole and a shaft. It is the intentional difference between maximum limits of mating parts to accomplish the desired fit. The machining allowance is the layer of metal removed in machining a surface. Besides "design tolerance", there are also "operational tolerances. " An operational tolerance is the specified machining accuracy of a surface in an intermediate operation followed by one or several more operations for machining the same surface. The machining allowances depend upon the method employed for making the blank. These methods vary for various scales of production.
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; X0 P1 ~. W( w1 P1 C2 {Fits. In machine construction, many of the parts have close and important relation to one another, and a certain amount of hand-fitting is essential. Fits can be classed as sliding fits, running fits, forced fits and shrink fits. 机械零件要制造得使零件之间可以互换。换句话说，一台机器或一个机械装置的任何一个零件都要制成一定的尺寸和形状，使其能够装在同类型的任何一台别的机器或机械装置上。为了使零件可以互换，每个零件的尺寸都要做得能和它的配合件装配良好。

极限：极限是为某一尺寸规定的最大和最小值。例如，一个孔的名义直径是一英寸，而其极限尺寸表示为 0.999/1.001，那么不大于1.001英寸，也不小于0.999英寸的任一零件都是合格的。

6 {' Q+ |4 S% e8 {0 G' I* R8 d4 h. M公差：极限的上、下限之间的差称为公差。如果最大极限为 1.001英寸，最小极限为 0.999英寸，则公差为0.002英寸。公差在图纸上有几种不同的麦示方法。

. X! Z0 ]) v5 |8 e+ V配合公差与加工留量：配合公差主要用于配合，例如孔与轴的配合。配合容差是配合件最大极限之间故意留出的一个量，使二者可以实现所要求的配合。机械加工留量是加工一个表面时被切除去的金属层。除了“设计公差”外，还有“工序公差”。一个加工中的表面，如果其后还需要经过一道或数道工序加工，那么这个表面所规定的加工精确度，就叫工序公差。机械加工留量的大小取决于制造毛坯所采用的方法。生产规模不同，采取的方法也不相同。
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配合：在机械制造中，许多零件之间都有着重要的密切的关系。有一些装配工作要用手工完成。配合可分为滑配合、转配合、压配合和冷缩配合。

lv2006

配合应该分:过盈,过渡和间隙配合吧?

kanwa3

兄弟说得好

makemo

虽然是中英文对照，可是只是看懂中文的

cwt12260898

同意2＃的说法，楼主说得老标准啦