GB/T 17852-2018Geometrical product specifications (GPS) -- Geometrical tolerancing -- Profile tolerancing (English PDF)

5.1 Overview

See GB/T 1182-2018 for the outline tolerance tolerance section in Basic Geometric Tolerance Labeling.

When the pattern is used in conjunction with the CAD model, the CAD model reference information should be marked in the pattern and the CAD model should be

Combined with GB/T 24734.

According to the principle of elements (see 5.4 of GB/T 4249-2018), the profile specification applies by default to a definition according to ISO 22432.

Complete single element. It is the responsibility of the designer to specify the elements or parts of the specification that apply to the specification, and the appropriate symbols can be used on the 2D drawings.

Note or defined in the CAD model.

According to the independent principle (see GB/T 4249-2018, 5.5), when a profile specification is applied to multiple ISO 22432

When a complete single element is defined, the specification applies to these elements independently by default. When the profile specification applies to multiple features, if you want

When these elements are considered as a whole or the tolerances of these elements are bound, the designer is responsible for using the appropriate two-dimensional pattern.

The symbology is defined or defined in the CAD model.

When using the "Full Surface" and "Full Week" labels in geometric tolerance labels, they should be combined with UF, CZ or SZ to

Clarify whether the specification applies to a composite element, either by defining a combined tolerance band or by defining a set of independent tolerance bands, unless

All non-redundant degrees of freedom with tolerance bands are locked by the reference referenced.

Note 1. When the specification defines a set of tolerance bands, and all its unconstrained degrees of freedom have been locked with reference to the reference, CZ has the same meaning as SZ.

Note 2. In the previous version of this standard, no other mark was used when using the "full week" specification. This will make its meaning vague and cannot be clearly identified.

Whether a semantic specification applies to multiple features independently or as a combined tolerance. The "full week" specification should be used together with UF, CZ or SZ.

A more secure method of labeling.

5.2 Default rules for profile tolerance labels

5.2.1 Rule A. Definition of the theoretical corrective element (TEF)

The theoretical correct size (TED) can be used to define the theoretical correctness factor (TEF) of the measured feature or to integrate it into the CAD model.

For size elements, the nominal shape of the TEF should be defined, but the nominal size of the TEF may not be defined, see Figure 4b).

These TEDs can include.

--- Clear TED;

---Default TED;

--- a table of numerical and interpolation algorithms;

--- Mathematical functions containing splines and other formulas;

--- Refer to the CAD model query.

If the TEF is displayed as a nominal line or a nominal plane on the drawing and is not labeled to define it as another nominal shape, by default

TED definitions can be considered as nominal or nominal planes.

The nominal shape of the TEF can be defined by default as a circle, a cylinder, a sphere, or a cone.

When the baseline size has a defined TED definition, the nominal shape of the TEF can be defined as a ring.

The size of a dimension feature is considered undefined unless there is a clear TED definition, so its size is also variable. Unless there is a clear

The exact TED definition, otherwise the busbar dimensions of the ring are considered undefined. See also rule F and rule G.

Note. The diameter of the center plane of the tolerance zone is fixed at the nominal size.

Figure 1 defines the nominal profile of the ball (given by TED)

If the TEF of a feature is defined using a table containing multiple sets of coordinates, a defined imputation should be given for the defined point between the given points.

algorithm.

Note 1. The method of labeling the interpolation algorithm has not been standardized.

Note 2. The non-exhaustive interpolation algorithm table can include.

---Linear interpolation;

---Cubic spline interpolation (periodic or aperiodic);

---NURBS.

Example. All points are connected to each other in a straight line.

When TEF is integrated in the CAD model, it should comply with GB/T 24734.

5.2.2 Rule B. Type of the measured element

Chapter 6 of GB/T 1182-2018 gives an labeling rule that distinguishes whether the measured feature is a component or an exported feature.

When the feature symbol in the tolerance sash is a polygon profile symbol, the measured feature is a component or derived feature.

When the feature symbol in the tolerance sash is a line profile symbol, the measured feature is.

---Export elements (see B.15);

--- Any line element in a specified direction on the identified composition or export face (see B.14); or

--- A specified line feature on the identified component or export face.

If the feature being measured is a line feature identified on a polygon feature, the location of the line feature should be identified using TED.

If the measured feature is an arbitrary line feature in a specified direction on the identified polygon feature, the direction of the line feature should be intersected.

The plane sash is used to identify it, see Chapter 13 of GB/T 1182-2018.

5.2.3 Rule C. Definition of tolerance zone

See Figure 2.

Unless otherwise specified, for surface profile features, the tolerance band shall be limited to a series of balls with a diameter equal to the tolerance value and the center of the sphere on the TEF.

See Rule E, Rule F, and Rule H between the two isometric envelopes.

Unless otherwise specified, for line profile features, when the tolerance value is constant and the front is not marked with phi, the tolerance band shall be limited to the diameter, etc.

For the tolerance value, the center of the circle is located between the two equidistant coplanar lines of a series of circles on the TEF, see rule E, rule F and rule H.

Unless otherwise specified, for line profile features, when the measured feature is the derived line and the tolerance value is marked phi, the tolerance band shall be limited to

The diameter is equal to the tolerance value, and the center of the sphere is located inside the envelope of a series of balls on the TEF, see rule H.

Note. See also 8.2.2.1.1 of GB/T 1182-2018.

Description.

1---TEF;

2---two balls or circles to represent the infinite number of balls or circles defining the tolerance band along the TEF;

3---tolerance band boundary;

t---tolerance value.

Figure 2 Definition of tolerance zone

For the line profile feature of the component, the intersecting plane sash fully defines the direction of the intersecting plane containing the tolerance band, for example,

Set it parallel to the reference plane or perpendicular to the reference axis.

In other cases, such as being defined perpendicular to the reference plane or parallel to the reference axis, one of the directional angles may be unlocked. at this time,

If the rule perpendicular to the face feature defines a uniform direction for each contour, then the intersection plane should be perpendicular to the face feature, see

image 3.

If the specification perpendicular to the polygon feature is that the direction defined by each contour is not uniform, such as a complex surface that is distorted along the contour,

The angle of one direction of the intersecting plane is not locked, and the direction element grid should be used to define the angle of the second direction of the intersecting plane.

a) Specification b) Direction of the intersecting plane containing the tolerance zone

Description.

1---the intersection plane is perpendicular to the reference plane B;

The 2---intersection plane is perpendicular to the measured element at each position.

Figure 3 The direction of the intersecting plane, including the tolerance band of the line profile feature

5.3 Profile Tolerance Rule with Additional Specification Elements

5.3.1 Rule D. Measured element specification element

If the measured element is not a complete single element, it should be marked with the tool given in GB/T 1182-2018, such as SZ,

CZ, UF, "full surface", "full week" and "interval", or query CAD model (see B.5, Note 2). To prevent ambiguity, in the geometric specification, "all

The "surface" and "full circumference" shall be used together with one of the SZ, CZ or UF unless all unconstrained degrees of freedom of the tolerance band have been locked by the reference system.

SZ, independent tolerance band, modifier treats a single set of features as independent features with tolerances independent of each other. Because there are multiple measurements to be tested

Therefore, it should also be specified using the same number of features.

CZ, combined tolerance band, modifier treats a single set of features as separate features, but combines their tolerance bands. Because the measured elements are built

Collection, so if there are no exported features in a single feature, you cannot define an exported feature. Therefore, when the functions of the measured elements are independent, but mutual

When there is a relationship, it is appropriate to use the CZ modifier. The CZ modifier defines only one specified feature.

UF, federated features, modifiers build a composite feature based on multiple single features. Even if there are no exported features in a single feature,

You can define this composite feature as an export feature. Therefore, when a function is associated with a component that is considered to be a single element, or

UF modifiers are appropriate when exporting features.

A specification of a union feature or its derived features creates a tolerance band for the composite feature or its derived features. Because there is only one combination

Elements, so there is only one stipulated feature.

In the profile tolerance tolerance of the component, the application difference between UF and CZ is very small, and it is limited to the transition zone between the features in the tolerance zone.

The shape difference of the domain.

5.3.2 Rule E. Asymmetric tolerance zone

For the constituent elements, UZ should be used if the tolerance band is not symmetrically arranged according to rule C. This rule is in GB/T 1182-

Given in 8.22.1.3 of.2018.

5.3.3 Rule F. Linear Offset Tolerance Band

If the offset of the tolerance band relative to the TEF is not specified, but the offset should be a constant value, OZ should be marked in the tolerance box.

This rule is given in 8.2.2.1.4.1 of GB/T 1182-2018.

When the tolerance band does not take into account the nominal size, the OZ modifier should be marked for linear dimension elements, see Figure 4a). If the shape of the TEF is fixed

Meaning, but the nominal linear size of the TEF is undefined, the OZ modifier should be marked, see Figure 4b).

a) has an OZ label and has been defined by TED

Specification of the surface profile of a ball of a size

b) OZ mark, and the nominal size is undetermined

The contour specification of the ball

Note. The diameter of the center plane of the tolerance zone is variable.

Figure 4 Linear dimension feature surface profile specification with OZ modifier

Note. Because there is no limit to the amount of offset, there are specifications for the OZ modifier, such as the specifications in Figures 4a) and b), which are usually compared with the no OZ modifier and used.

The specification of large tolerances is used in combination, as specified in Figure 1. When the two tolerances are met at the same time, the combination can control the shape of the measured element to a larger size.

Within the fixed tolerance band.

5.3.4 Rule G. Angle offset tolerance band

For angular dimension elements, the VA modifier (variable angular dimension) should be marked when the tolerance band does not take into account the nominal dimensions. If TEF

The shape is defined, but the nominal angular dimension of the TEF is undefined and the VA modifier should be marked. This rule is in GB/T 1182-2018

Given in 8.2.2.1.4.2.

5.3.5 Rule H. Variable width tolerance zone

If the tolerance band width is variable, it should be marked with the tool given in 8.2.2.1.1 of GB/T 1182-2018.

5.3.6 Rule I. Filtering feature specification elements

If the specification applicable to the extracted features contains the specified filtering requirements, then the use of GB/T 1182-2018 in 8.2.2.2.1

Give the tools to mark.

5.3.7 Rule J. Fitting and parameter specification elements

If a non-relative profile feature (profile shape specification) is compared to a non-default reference feature, and/or a non-default parameter

Use, then should be marked with the tools given in 8.2.2.3.1 and 8.2.2.3.2 of GB/T 1182-2018.

Note. The default fitting criteria and parameters are given in 8.2.2.3.1 and 8.2.2.3.2 of GB/T 1182-2018.

5.3.8 Rule K. Fitting the measured feature specification element

If the specification applies to the fitting element rather than the identified element itself, then it shall be given in 8.2.2.2.2 of GB/T 1182-2018.

Out of the tool to mark.

5.3.9 Rule L. Non-rigid parts

If the specification applies to non-rigid parts with or without constraints, the notation method given in GB/T 16892 should be used.

rule.

Appendix A

(informative appendix)

Combined element

Combination elements not fully defined by TED, and one of the types given by Rule A, but not satisfied with the size defined by TED

The elements required by the foot rule cannot be specified using the profile tolerance because they do not have a well-defined shape. Some examples are shown in Figure A.1.

Shown.

a) b)

c) d) e)

Figure A.1 Theoretically correct geometrically blurred elements

Since the nominal distance between the two semicircles is undefined, the TEF of the feature is blurred in Figure A.1a).

Since the nominal radius of one of the two semicircles is undefined, the TEF of the feature is blurred in Figure A.1b).

Since the nominal distance of the arc center is undefined, the TEF of the feature is blurred in Figure A.1c).

Since the nominal diameter of the arc is undefined, the TEF of the feature is blurred in Figure A.1d).

Since the nominal size of the baseline is undefined, the TEF of the feature is blurred in Figure A.1e).

a)

b)

c)

Figure A.2 Theoretically correct geometrically defined elements

Note 1. The UF in Figure A.2a) and Figure A.2b) can be replaced by CZ.

Note 2. Since the plane in Figure A.2b) is tangent to the semi-cylinder, the distance between them defaults to 10.

Since the nominal radius of the semicircle and the distance between the two circles have been defined with a definite or default TED, it is necessary in Figure A.2a)

The TEF of the prime is clear.

Since the nominal diameter of the arc and the nominal distance of the center of the arc have been defined with explicit or default TED, in Figure A.2b)

The TEF of the element is clear.

Since the nominal size of the baseline has been defined by TED, the TEF of the feature in Figure A.2c) is clear.

Appendix B

(informative appendix)

Rule icon

B.1 Overview

The following examples are diagrams of the underlying rules and rules A through F. They do not increase or decrease or change the content of the rules.

--- Example 1. Specification of the profile of a single feature (B.2).

--- Example 2. Surface profile specification for combined features (B.3).

--- Example 3. Surface profile specification for a set of independent features (B.4).

--- Example 4. Surface profile specification for joint features (B.5).

--- Example 5. Asymmetric surface profile specification for joint elements (B.6).

--- Example 6. Offset surface profile specification for joint features (B.7).

--- Example 7. Combination face profile specification for a set of features (B.8).

--- Example 8. Surface profile specification for combined features subject to datum constraints (B.9).

--- Example 9. Combination of fixed tolerance band specification and offset tole...