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Tolerancing Principle GB/T 4249-1996eqv ISO 8015:1 of principle of public errand of level of state of People's Republic of China985 replace limits of GB 4249-84 1 this standard provided certain measure (linear dimension and angle dimension) tolerancepublic errand and form between tolerancepublic errand the principle of correlation. This standard applies to public errand of the dimension in technical cartography and relevant document, dimension and form tolerancepublic errand, in order to decide the size of spare parts element, appearance and positional feature. 2 cite the clause that following standard place contains the level, through citing in this standard compose makes the clause of this standard. When this standard is published, what show version to all be effective. All standards can be edited, use this level each just should be discussed use following level the possibility of newest version. GB/T 1182-1996 appearance and general rule of positional public errand, definition, symbol and appearance of design notation GB/T 16671-1996 and positional common difference are the biggest the hypostatic requirement, least hypostatic demand and reversible requirement on design of 3 independent principles given requirement of each dimension and appearance, position all is independence, part of one's job does not satisfy a requirement. If be opposite,the correlation between dimension and appearance, dimension and position has specific requirement to answer to set on the design. Independent principle is dimension public errand and form the basic principle that tolerancepublic errand correlation follows. 4 public errand 4.

1 dimension public errand 4.

1.

The local and real measure that public errand of dimension of linear of public errand of 1 linear dimension controls element only (the law measured) at 2 o'clock, the appearance error that does not control element itself (the flatness error) of the circularity that is like columnar element and axes linearity error or parallel and planar element. Appearance error should by the appearance public errand that tags alone, did not note appearance common difference or include the requirement accuses to take (1) seeing a picture. (A) (b) pursues 1 tag a specification: The local dimension of actual axis must be located in 149.

96 to 150 between; Linear dimension public errand (0.

04) does not control the appearance error of element itself. If pursue,1b) place is shown. 4.

1.

Public errand of angle of 2 angle public errand controls the angle variation between the ideal element of the element that be measured only, do not control the appearance error of the element that be measured, and the position of ideal element should accord with the smallest condition. Angle public errand the total direction of control line or element line, do not control its appearance error. Total direction is the direction that points to osculatory line, contacting a line is the largest space that contacts with real wire photograph for the smallest ideal linear (2) seeing a picture. The appearance error of real wire should by the appearance that tags alone tolerancepublic errand or did not note control of appearance public errand. Give typical examples pursues 2 graphs 3 tag a specification: A, B two be measured real essential factor decides its ideal element by the smallest condition respectively, the included angle between this two ideal element should be in given between two limits angle, the appearance error that angle public errand does not control real essential factor (3) seeing a picture. 4.

2 appearance and positional public errand no matter the local and real measure of element how, the element that be measured all should be located in given form inside tolerancepublic errand belt, and its form the error allows to reach maximum (4) seeing a picture. Give typical examples: Graph 4 tag a specification: Local and real measure of the axis should be between size of the biggest maximum and size of the smallest maximum, appearance error of the axis should be in given in corresponding figure public errand. No matter local and real measure of the axis how, its appearance error (error of circularity of sum of errors of element line linearity includes cross section odd arris round error) allow to achieve given maximum (5) seeing a picture. A) B) pursues public errand of dimension of ― of 55 relevant requirements and form on the design of tolerancepublic errand requirement that tolerancepublic errand concerns each other given dimension public errand and form the tolerancepublic errand requirement that tolerancepublic errand concerns each other, the department points to include requirement, the biggest hypostatic demand (include reversible requirement to apply at the biggest hypostatic demand) ask with the least substance (include reversible requirement to apply at) of the least hypostatic demand. 5.

1 include the requirement includes the requirement applies to single essential factor to be like columnar surface or two parallel surface. Include the requirement states real essential factor should abide by his the biggest substance is attrib border, its are local and actual dimension must not exceed the smallest hypostatic size. Use include the single essential factor of the requirement should be added after its dimension extreme deviation or public errand bear code name note a sign " " (6) seeing a picture. Give typical examples: Graph 6 tag a specification: Columnar surface must be inside the biggest hypostatic border, this attrib border dimension is F150 of the largest hypostatic size. Its are local and actual dimension must not is less than 149.

96 (sees graph 7) . A) B) C) D) pursues 75.

2 the biggest substance ask the biggest substance asks to apply to central element. The biggest hypostatic demand is to control the real profile of the element that be measured to be in its the requirement of a kind of public errand in border of the biggest tangible substantial results. When its real measure deviate is the biggest when hypostatic dimension, allow its entity the tolerancepublic errand value that error value exceeds his to give out. Should tag a symbol in the design right now " " , tag a method to see GB/T 1182. When its form the error is less than the form that give out tolerancepublic errand, allow its again when real measure exceeds the largest hypostatic size, can use reversible requirement at the biggest hypostatic demand. Should be in at the same time right now its form the form of the biggest hypostatic demand in tolerancepublic errand sash the symbol is tagged after tolerancepublic errand is worth " ® " . Specific tag a method to see GB/T 16671. 5.

3 the least substance ask the least substance asks to apply to central element. The least hypostatic demand is to control the real profile of the element that be measured to be in its the requirement of a kind of public errand in border of the least hypostatic actual effect. When its real measure deviate is the smallest when hypostatic dimension, allow its entity the tolerancepublic errand value that error value exceeds his to give out. Should tag a symbol on the design right now " " , tag a method to see GB/T 1182. When its form the error is less than the form that give out tolerancepublic errand, allow its again when real measure exceeds the smallest hypostatic size, can use reversible requirement at the least hypostatic demand. Should be in at the same time right now its form the form of the least hypostatic demand in tolerancepublic errand sash the symbol is tagged after tolerancepublic errand is worth " ® " . Specific tag a method to see GB/T 16671. When the design of principle of 6 public errand tags a design to go up or this level is being used in technical file, should make clear: Tolerancepublic errand principle presses GB/T 4249. The appendix that appendix A (hints) 0 form the 0 form that the biggest hypostatic demand can use when element of tolerancepublic errand correlation observes the biggest hypostatic border tolerancepublic errand. The 0 form that associated element uses the biggest hypostatic demand when tolerancepublic errand is tagged, ask actually border outline must not surmount the biggest hypostatic border everywhere, and this are attrib border should with fiducial maintain a design to go up given geometry concerns, the local and real measure of element real profile must not surmount the smallest hypostatic size. Give typical examples: A)b)c) graph A1 tags a specification: Columnar surface must be inside the biggest hypostatic border, this attrib border dimension is F50 of the largest hypostatic size, and as perpendicular as datum plane A. The local and real measure of actual cylinder must not is less than 49.

975(sees graph A1) . CNC Milling