GB/Z 18620.2-2002 Specification for the inspection of cylindrical gears Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash
Some standard content:
ICS21.200
National standardization guidance technical documents of the People's Republic of China GB/Z18620.2—2002
idtIS0/TR10064-2:1996
Cylindrical gears-Code of inspection practicePart 2Inspection related to radial composite deviations, runout, tooth thickness and backlash backlash2002-01-10 Issued
People's Republic of China
General Administration of Quality Supervision, Inspection and Quarantine
2002-08-01 Implementation
GB/Z18620.2—2002
ISOForeword
Referenced standards
Symbols, related items and definitions·
Measurement of radial comprehensive deviation
Measurement of radial runout, determination of eccentricity 5
Tooth thickness, normal length and cross-ball (cylinder) size Measurement of size 7
Tolerance and fit of gears…
Appendix A (Standard Appendix)
Appendix B (Suggestive Appendix)
Backlash and tooth thickness tolerances
Literature list
TKAONiKAca
GB/Z18620.2--2002
This guidance technical document is equivalent to ISO/TR10064-2:1996 "Specification for the inspection of cylindrical gears Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash". The technical content is exactly the same as ISO/TR10064-2. In the process of revising GB/T10095-1988, it was unanimously agreed that the description and opinions on gear inspection methods should be raised to the modern technical level. Due to the increase in content and other considerations, it was decided to publish the relevant parts as guidance technical documents in separate volumes. Thus, together with Part 1 and Part 2 of GB/T10095, a system of standards and guiding technical documents (listed in Chapter 2 and Appendix B) is formed.
GB/Z18620, under the general title "Specification for the Implementation of Cylindrical Gear Inspection", includes the following parts: Part 1: Inspection of tooth surfaces on the same side of gear teeth; Part 2: Inspection of radial comprehensive deviation, radial runout, tooth thickness and backlash; Part 3: Gear wear, shaft center distance and axis parallelism; Part 4: Inspection of surface structure and gear tooth contact spots. This guiding technical document is for reference only. Suggestions and opinions on this guiding technical document may be reflected to the standardization administrative department of the State Council.
Appendix A of this guiding technical document is a standard appendix, and Appendix B is a suggestive appendix. This guiding technical document is proposed by the China Machinery Industry Federation. This guiding technical document is under the jurisdiction of the National Technical Committee for Gear Standardization. This guiding technical document was drafted by the Zhengzhou Machinery Research Institute. The main drafters of this guidance technical document are: Zhang Min'an, Zhang Yuanguo, Li Shizhong, Yang Xingyuan, Wang Qi, Xu Hongji. GB/Z18620.2—2002
ISOForeword
ISO (International Organization for Standardization) is a worldwide federation composed of national standardization groups (ISO member groups). The work of formulating international standards is usually completed by ISO's technical committees. If each member group is interested in a standard project established by a technical committee, it has the right to participate in the work of the committee. International organizations (official or unofficial) that maintain contact with ISO can also participate in the relevant work. In the field of electrotechnical standardization, ISO maintains a close cooperative relationship with the International Electrotechnical Commission (IEC). The main task of the technical committee is to develop international standards, but in special circumstances, the technical committee may recommend the publication of one of the following types of technical reports (TR):
-Type 1
When repeated efforts have not yet obtained the support required to publish an international standard; when the project is still in technical development, or for various reasons, it is only possible in the future rather than at present-Type 2
Agreed to become an international standard;
Type 3
When a technical committee collects information that is different from the international standards that are normally published (for example, to adapt to the current state of the art).
Technical reports of type 1 and type 2 should be reviewed within three years of publication to determine whether they can be transformed into international standards. Technical reports of type 3 do not necessarily have to be reviewed and are used until the information provided is no longer considered useful or valid. ISO/TR10064-2 is a technical report of type 3, which was developed by ISO/TC60 Gear Technical Committee. International Standard ISO 1328:1975 contains, in addition to definitions and tolerances for gear tooth elements, advice on relevant inspection methods.
During the revision of ISO 1328:1975, it was agreed that the description and advice on gear inspection methods should be brought up to date. Due to the increase in content and other considerations, the Technical Committee decided to publish the relevant paragraphs as a third type of technical report in separate volumes. It was also decided that, in addition to this technical report, a number of documents, including the references listed in Chapter 2 and the literature listed in Appendix B, should be used as guidance. ISO/TR 10064, under the general title "Specification for the inspection of cylindrical gears", consists of the following parts: - Part 1 Inspection of tooth flanks on the same side of the gear teeth; - Part 2: Inspection of combined radial deviation, radial runout, tooth thickness and backlash; - Part 3: Recommendations for gear tooth, shaft centre distance and axis parallelism; - Part 4: Recommendations for the inspection of surface structure and tooth contact spots. N
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National Standardization Guiding Technical Documents of the People's Republic of China Cylindrical gears-Code of inspection practice--Part 2: Inspection related to radial composite deviationsrunout,tooth thickness and backlash1Scope
GB/Z18620.2--2002
idtISO/TR10064-2:1996
This guiding technical document is the inspection and implementation specification for radial composite deviations, radial runout, tooth thickness and backlash of involute cylindrical gears, that is, the inspection and implementation specification involving double-sided contact. This document provides an analysis of gear inspection methods and measurement results, supplements GB/T10095.2, and most of the terms used have been defined in GB/T10095.2.
Appendix A provides methods for selecting tooth thickness tolerance and minimum backlash when gears mesh, including recommended values for the minimum backlash. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this guidance technical document through reference in this guidance technical document. The versions shown are valid when this guidance technical document is published. All standards will be revised, and parties using this guidance technical document should explore the possibility of using the latest versions of the following standards: GB/T1356—2001 Standard basic rack tooth profile for cylindrical gears for general machinery and heavy machinery (idtISO53:1998) GB/T1357--1987 Involute cylindrical gear module (negISO54:1977) GB/T10095.1-2001 Involute cylindrical gear accuracy Part 1: Definition and allowable value of tooth surface deviation on the same side of the gear (idtISO1328.1:1997)
GB/T10095.2--2001
GB/Z18620.1--2002
GB/Z18620.3-2002
3 Symbols, related items and definitions
3.1 Lowercase letter symbols
Precision of involute cylindrical gears Part 2: Definitions and allowable values of radial combined deviation and radial runout (idtISO1328.2:1997)
Cylindrical gear inspection implementation specification Part 1: Inspection of tooth flanks on the same side of the gear teeth (idtISO/TR10064-1:1992)
Cylindrical gear inspection implementation code Part 3: Gear bearing, shaft center distance and axis parallelism (idtISO/TR10064-3:1996)
Center distance
Pitch circle diameter
Base circle diameter
Top circle diameter
Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on January 10, 2002 mm
Implemented on August 1, 2002
Snactual
S func
3.2 Capital letter symbols
Wauactual
3.3 Greek letter symbols
Eptest
3.4 Lower angle symbol
Pitch circle diameter
Eccentricity
GB/Z18620.2—2002
Comprehensive radial deviation of one tooth
Tooth top height
Tooth height of pitch circle chord
Normal modulus Number
Normal tooth thickness
“Actual tooth thickness”
Normal chordal tooth thickness
“Functional tooth thickness”
Tooth profile modification coefficient
Diameter of the measuring ball (cylinder)
Theoretical diameter of the measuring ball (cylinder)Lower allowable deviation of tooth thickness
Upper allowable deviation of tooth thickness
Total radial comprehensive deviation
Radial runout
Radial runout obtained by comprehensive test||t t||Size of cross ball (cylinder)
Normal length
Actual normal length
Theoretical normal length
End face pressure angle
Normal pressure angle
Helix angle
Prism (anvil) half angle
Longitudinal overlap
Longitudinal overlap (during detection)
Tooth groove half angle
Tooth thickness half angle
Pinion
Gear||tt ||Measurement of gear
Any (given) diameter
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3.5 Definitions
3.5.1 Definition of comprehensive deviation
GB/Z18620.2--2002
The "reference axis" of a component is defined with the help of a reference plane. In most cases, the axis of the inner hole can be represented by the axis of the matching working mandrel (see GB/Z18620.3). In the radial comprehensive deviation, the "geometric axis of the gear tooth" refers to the axis that, when used for measurement, will obtain the minimum root mean square comprehensive total deviation after the gear rotates one full circle.
3.5.2 Definition of tooth thickness
The "nominal tooth thickness s." on the normal plane on the dividing cylinder refers to the theoretical tooth thickness, and the gear is meshed with a matching gear with the theoretical tooth thickness without backlash below the basic center distance. The nominal tooth thickness can be calculated using the following formula: For external gears
For internal gears
For helical gears, the sn value should be measured in the normal plane. #+2tanagx
2tanans
(2)
The "maximum and minimum limits" of tooth thickness, s.. and sm, refer to the two extreme allowable dimensions of tooth thickness. The actual dimension of tooth thickness should be between these two extreme dimensions (including the extreme dimensions), see Figure 1. Wethe
Thn=Ebns-Ebni
Theoretical
Actual
Nominal tooth thickness
Minimum limit of tooth thickness
SnsMaximum limit of tooth thickness
Snactual actual tooth thickness
Lower allowable deviation of tooth thickness
Upper allowable deviation of tooth thickness
Tooth thickness deviation
Tooth thickness tolerance
Tem=Esns—Eami
Figure 1 Allowable deviation of normal length and tooth thickness The upper and lower deviations of tooth thickness (E. and E..) are collectively referred to as the limit deviations of tooth thickness. See formula 3, formula 4 and Figure 1. Limit
GB/Z18620.2—2002
Esns =Sns-Sn
Esni = Sai— Sn
“Tooth thickness tolerance” T refers to the difference between the upper and lower deviations of tooth thickness Tsn=Esns-Eani
（3）
（4）
·（5)
The determination of the design value of tooth thickness should take into account engineering factors such as gear geometry, gear tooth strength, installation and backlash. Under given application conditions, how to determine the design tooth thickness is not within the scope of this guiding technical document. “Actual tooth thickness” snstua refers to the tooth thickness determined by measurement. “Functional tooth thickness” Srum. Refers to the maximum tooth thickness value obtained by radial comprehensive (double-sided) meshing test using a calibrated measuring gear. This measurement includes the combined effect of the deviations of the tooth profile, helix, pitch, etc., which is similar to the concept of the maximum material state, see 6.5. It must not exceed the designed tooth thickness.
The "effective tooth thickness" of a gear refers to the tooth thickness obtained by measurement plus the combined effect of the deviations of the gear teeth and the installation, which is similar to the meaning of "functional tooth thickness".
This is the final inclusion condition, which includes all the influencing factors that must be considered when determining the maximum material state. The element deviations of the matching gears may have superimposed effects or mutually offsetting effects at different angular positions of meshing. It is impossible to distinguish the individual gear tooth element deviations from the "effective tooth thickness". 3.5.3 Definition of backlash
"Backlash" is the gap formed between the two non-working tooth surfaces when the working tooth surfaces of two matching gears are in contact, as shown in Figure 2. Note: Figure 2 is drawn at the tightest center distance position. If the center distance increases, the backlash will also increase. The maximum effective tooth thickness (minimum backlash) is different from the measured tooth thickness due to the combined influence of the deviation of each element of the gear tooth and the influence of installation. It is similar to the functional tooth thickness. This is the final inclusion condition. It includes all influencing factors. These influencing factors must be considered when determining the maximum entity state. Usually, the backlash (working backlash) under stable working conditions is different from (smaller than) the backlash (assembly backlash) measured when the gear is installed in the box under static conditions. Maximum effective tooth thickness Swtna
Specified maximum tooth thickness
Maximum material state
(meshing gears)
Maximum backlash at the tightest center distance
Minimum backlash j
1Minimum material state
Allowed upper deviation tooth profile
Minimum effective tooth thickness s..
Specified minimum tooth thickness
Allowed lower deviation tooth profile| |tt||Tolerance zone specified by No. 0.5Tmt
Single element measurement
Figure 2 Tooth thickness on end plane
Special specification with radial
Comprehensive meshing test
Maximum entity state
(dominant gear)
Minimum entity state
"Circumferential backlash"i (Figure 3) is the maximum value of the pitch arc length that the other gear can rotate when one of the two-phase meshing gears is fixed. "Normal backlash"jba (Figure 3) is the shortest distance between the non-working tooth surfaces of the two gears when the working tooth surfaces of the two gears are in contact with each other. Its relationship with the circumferential backlash is expressed by the following formula: GB/Z18620.2—2002
jbn jwtcosawt cosβ
（6）
"Radial backlash" i (Figure 3) The center distance of the two matching gears is reduced until the left and right tooth surfaces are in contact. The amount of reduction is the radial backlash:
2tanawt
j (on the base circle tangent plane)
Base circle tangent plane trace
Tooth surface trace
Figure 3 Relationship between circumferential backlash jwt, normal backlash jbn and radial backlash j. Pitch circle
"Minimum backlash" itmi is the minimum circumferential backlash on the pitch circle, that is, the circumferential backlash at the tightest allowable center distance under static conditions when the gear tooth with the maximum allowable effective tooth thickness meshes with the matching gear tooth with the maximum allowable effective tooth thickness (Figure 2). The so-called tightest center distance refers to the minimum working center distance for external gears and the maximum working center distance for internal gears. The "maximum backlash" i is the maximum circumferential backlash on the pitch circle, i.e. the circumferential backlash at the maximum permissible center distance under static conditions when a tooth with the minimum permissible effective tooth thickness meshes with a matching tooth with the minimum permissible effective tooth thickness (Fig. 2). 4 Measurement of radial composite deviation
4.1 Principle of measurement
When testing radial composite deviation, a pair of gears are placed on the device used, one of which is mounted on a fixed shaft and the other on a shaft with a slideway, which is equipped with a spring device so that the two gears can mesh closely in the radial direction (see Figure 4). The change in center distance is measured during rotation and, if necessary, a center distance change curve can be displayed. For most testing purposes, a measuring gear is used to test the product gear. The measuring gear needs to be made very accurately so that its influence on the radial composite deviation is negligible. In this case, an acceptable record can be displayed when a product gear rotates one full circle.
The total radial composite deviation F of the tested gear is equal to the maximum center distance change during one full rotation of the gear, which can be determined from the recorded line diagram. The radial composite deviation of a tooth is equal to the change in the center distance of the gear when it rotates through one pitch angle (see Figure 5). The tolerance values given in GB/T10095.2 apply to this measurement made with a measuring gear. 5
Measurement gear
GB/Z18620.2—2002
Product gear
Use the measurement direction
In the rotation, measure the change of the center distance Z view (enlarged)
Figure 4 Principle of measuring radial comprehensive deviation
Figure 5 Radial comprehensive deviation curve
No backlash meshing
It is necessary to pay great attention to the accuracy and design of the measuring gear, especially the pressure angle of its meshing with the product gear, which will affect the measurement result. The measuring gear should have enough meshing depth to make it contact with the entire effective tooth profile of the product gear, but should not contact with the ineffective part or root. The way to avoid such contact is to increase the tooth thickness of the measuring gear to be enough to compensate for the backlash tolerance of the product gear. When using this method to grade the quality of precision gears, the accuracy and measurement steps of the measuring gear used should be agreed upon by the purchaser and the supplier.
For spur gears, the specified tolerance values can be used to determine the accuracy grade, but when used for helical gears, the tooth width of the measuring gear should be designed so that it is equal to or less than 0.5 est of the product gear. The design of the measuring gear should be agreed upon by the purchaser and the supplier. The longitudinal overlap can affect the radial composite measurement results of helical gears. The influence of the tooth profile deviation will be obvious for spur gears, but it will be hidden in helical gears due to the presence of multiple teeth and diagonal contact lines. The curve recorded for a full rotation of the gear is close to a sine shape (amplitude f.), indicating the eccentricity f. of the gear. Figure 5 shows how to draw a sine curve on this curve. The eccentricity of the gear is the offset between the geometric axis of the gear tooth and the reference axis (i.e., the hole or shaft).
4.2 Application of radial composite deviation data
The radial composite deviation includes the components of the composite deviation of the right and left tooth surfaces. Therefore, it is impossible to determine the single deviation of the tooth surface on the same side. The measurement of radial composite deviation can quickly provide information about quality defects caused by the clamping of production machines, tools or product gears. This method is mainly used for the detection of mass-produced gears and small-module gears. The composite deviation of one tooth that occurs for each pitch rotation helps to reveal the tooth profile deviation (usually the tooth profile tilt deviation). A large individual composite deviation of one tooth indicates a large pitch deviation or a damaged tooth (see Figure 6). After proper calibration of the clamping and detection methods of the product gears, this measurement process can also be used to determine the center distance of the minimum side clearance meshing of the product gears, see GB/Z18620.3 for recommendations on shaft center distance and axis parallelism. In addition, this step is also useful for detecting gears that need to run with minimum side clearance, because the range of functional tooth thickness can be easily obtained from the radial composite deviation. 6
YKAoNrKAca
To determine the accuracy grade:
GB/Z18620.2--2002
a) For spur gears, the product gears shall be tested with a measuring gear that can contact 100% of the effective tooth profile. See 5.5 of GB/T10095.2-2001. The tolerance values of the radial comprehensive total deviation and the radial comprehensive deviation of one tooth given in GB/T10095.2 are used to determine the accuracy grade of spur gears. It must be emphasized that because the tooth surfaces on both sides work at the same time, the accuracy grade obtained by double-sided meshing testing cannot be directly related to the accuracy grade obtained by testing with a single element. b) For helical gears, although the tolerances in GB/T10095.2 are for spur gears, they can also be used to evaluate helical gears if both the purchaser and the supplier agree. In this case, the overlap e8tes when meshing with the gear should meet the requirements of 4.1. Radial runout
This is the fluctuation of the center distance of the product gear in one revolution, which is shown as a slowly increasing and decreasing curve on the line graph (i.e. the gear ratio changes). Damaged teeth
Pitch deviation
On the line graph, the recording pen between two adjacent teeth appears suddenly and irregularly offset with varying amplitudes. Profile deviation
The smaller wave on the curve indicates the deviation between the tooth profile and the theoretical involute tooth profile, and each wave corresponds to the contact period of one tooth. 335
Pressure angle deviation (tooth profile inclination deviation)
They appear on the curve graph as regularly spaced and pointed vertical offsets, and each offset corresponds to the contact period of one tooth. Group. Explanation of radial combined deviation
5 Measurement of radial runout and determination of eccentricity 5.1 Principle of measurement
The radial runout F of a gear tooth is the difference between the maximum and minimum radial positions of a suitable probe (ball, anvil, cylinder or prism) placed in each tooth groove, tooth by tooth, relative to the reference axis of the gear when the gear rotates (see Figure 7). If a ball, cylinder or anvil is used to contact both sides of the tooth in the tooth groove, the tolerance table listed in Appendix B of GB/T10095.22001 can be applied. In some cases, a rider is used to contact both sides of the tooth, and the tolerance table is not intended to be used in this case. The diameter of the ball should be selected so that it can contact the middle part of the tooth groove and should be placed in the center of the tooth width (see 6.3 Calculation of ball diameter). 5.2 Dimensions of the anvil for measuring radial runout
The dimensions of the anvil should be chosen so that it contacts the tooth surface approximately at the pitch circle in the tooth groove. The half angle of the prism can be determined by the following approximation, where t, αy and n are the angles of contact on the measuring circle (see Figure 8). 7
GB/Z18620.2—2002
The anvil should contact the tooth surface at the center of the tooth width with a measuring circle of diameter d. Ball or cylinder
Anvil or prism
Figure 7 Principle of measuring radial runout
Oye ay + nye
cosayt
dcosat
Figure 8 Dimensions of the anvil for measuring radial runout
ikAoNrKAca
（9）
（10）2—2002
Product gear
Measure the change of center distance in the measurement direction
During rotation, measure the change of center distanceZ view (enlarged)
Figure 4 Principle of measuring radial comprehensive deviation
Figure 5 Radial comprehensive deviation curve
Backlash-free meshing
The accuracy and design of the measuring gear must be taken seriously, especially the pressure angle of its meshing with the product gear, which will affect the measurement result. The measuring gear should have enough meshing depth to make it contact with the entire effective tooth profile of the product gear, but should not contact with the ineffective part or root. The way to avoid such contact is to increase the tooth thickness of the measuring gear to compensate for the backlash tolerance of the product gear. When using this method to grade the quality of precision gears, the accuracy and measurement steps of the measuring gear used should be agreed upon by the purchaser and the supplier.
For spur gears, the specified tolerance values can be used to determine the accuracy grade, but when used for helical gears, the tooth width of the measuring gear should be designed so that it is equal to or less than 0.5 est of the product gear. The design of the measuring gear should be agreed upon by the purchaser and the supplier. The longitudinal overlap can affect the radial composite measurement results of helical gears. The influence of the tooth profile deviation will be obvious for spur gears, but it will be hidden in helical gears due to the presence of multiple teeth and diagonal contact lines. The curve recorded for a full rotation of the gear is close to a sine shape (amplitude f.), indicating the eccentricity f. of the gear. Figure 5 shows how to draw a sine curve on this curve. The eccentricity of the gear is the offset between the geometric axis of the gear tooth and the reference axis (i.e., the hole or shaft).
4.2 Application of radial composite deviation data
The radial composite deviation includes the components of the composite deviation of the right and left tooth surfaces. Therefore, it is impossible to determine the single deviation of the tooth surface on the same side. The measurement of radial composite deviation can quickly provide information about quality defects caused by the clamping of production machines, tools or product gears. This method is mainly used for the detection of mass-produced gears and small-module gears. The composite deviation of one tooth that occurs for each pitch rotation helps to reveal the tooth profile deviation (usually the tooth profile tilt deviation). A large individual composite deviation of one tooth indicates a large pitch deviation or a damaged tooth (see Figure 6). After proper calibration of the clamping and detection methods of the product gears, this measurement process can also be used to determine the center distance of the minimum side clearance meshing of the product gears, see GB/Z18620.3 for recommendations on shaft center distance and axis parallelism. In addition, this step is also useful for detecting gears that need to run with minimum side clearance, because the range of functional tooth thickness can be easily obtained from the radial composite deviation. 6
YKAoNrKAca
To determine the accuracy grade:
GB/Z18620.2--2002
a) For spur gears, the product gears shall be tested with a measuring gear that can contact 100% of the effective tooth profile. See 5.5 of GB/T10095.2-2001. The tolerance values of the radial comprehensive total deviation and the radial comprehensive deviation of one tooth given in GB/T10095.2 are used to determine the accuracy grade of spur gears. It must be emphasized that because the tooth surfaces on both sides work at the same time, the accuracy grade obtained by double-sided meshing testing cannot be directly related to the accuracy grade obtained by testing with a single element. b) For helical gears, although the tolerances in GB/T10095.2 are for spur gears, they can also be used to evaluate helical gears if both the purchaser and the supplier agree. In this case, the overlap e8tes when meshing with the gear should meet the requirements of 4.1. Radial runout
This is the fluctuation of the center distance of the product gear in one revolution, which is shown as a slowly increasing and decreasing curve on the line graph (i.e. the gear ratio changes). Damaged teeth
Pitch deviation
On the line graph, the recording pen between two adjacent teeth appears suddenly and irregularly offset with varying amplitudes. Profile deviation
The smaller wave on the curve indicates the deviation between the tooth profile and the theoretical involute tooth profile, and each wave corresponds to the contact period of one tooth. 335
Pressure angle deviation (tooth profile inclination deviation)
They appear on the curve graph as regularly spaced and pointed vertical offsets, and each offset corresponds to the contact period of one tooth. Group. Explanation of radial combined deviation
5 Measurement of radial runout and determination of eccentricity 5.1 Principle of measurement
The radial runout F of a gear tooth is the difference between the maximum and minimum radial positions of a suitable probe (ball, anvil, cylinder or prism) placed in each tooth groove, tooth by tooth, relative to the reference axis of the gear when the gear rotates (see Figure 7). If a ball, cylinder or anvil is used to contact both sides of the tooth in the tooth groove, the tolerance table listed in Appendix B of GB/T10095.22001 can be applied. In some cases, a rider is used to contact both sides of the tooth, and the tolerance table is not intended to be used in this case. The diameter of the ball should be selected so that it can contact the middle part of the tooth groove and should be placed in the center of the tooth width (see 6.3 Calculation of ball diameter). 5.2 Dimensions of the anvil for measuring radial runout
The dimensions of the anvil should be chosen so that it contacts the tooth surface approximately at the pitch circle in the tooth groove. The half angle of the prism can be determined by the following approximation, where t, αy and n are the angles of contact on the measuring circle (see Figure 8). 7
GB/Z18620.2—2002
The anvil should contact the tooth surface at the center of the tooth width with a measuring circle of diameter d. Ball or cylinder
Anvil or prism
Figure 7 Principle of measuring radial runout
Oye ay + nye
cosayt
dcosat
Figure 8 Dimensions of the anvil for measuring radial runout
ikAoNrKAca
（9）
（10）2—2002
Product gear
Measure the change of center distance in the measurement direction
During rotation, measure the change of center distanceZ view (enlarged)
Figure 4 Principle of measuring radial comprehensive deviation
Figure 5 Radial comprehensive deviation curve
Backlash-free meshing
The accuracy and design of the measuring gear must be taken seriously, especially the pressure angle of its meshing with the product gear, which will affect the measurement result. The measuring gear should have enough meshing depth to make it contact with the entire effective tooth profile of the product gear, but should not contact with the ineffective part or root. The way to avoid such contact is to increase the tooth thickness of the measuring gear to compensate for the backlash tolerance of the product gear. When using this method to grade the quality of precision gears, the accuracy and measurement steps of the measuring gear used should be agreed upon by the purchaser and the supplier.
For spur gears, the specified tolerance values can be used to determine the accuracy grade, but when used for helical gears, the tooth width of the measuring gear should be designed so that it is equal to or less than 0.5 est of the product gear. The design of the measuring gear should be agreed upon by the purchaser and the supplier. The longitudinal overlap can affect the radial composite measurement results of helical gears. The influence of the tooth profile deviation will be obvious for spur gears, but it will be hidden in helical gears due to the presence of multiple teeth and diagonal contact lines. The curve recorded for a full rotation of the gear is close to a sine shape (amplitude f.), indicating the eccentricity f. of the gear. Figure 5 shows how to draw a sine curve on this curve. The eccentricity of the gear is the offset between the geometric axis of the gear tooth and the reference axis (i.e., the hole or shaft).
4.2 Application of radial composite deviation data
The radial composite deviation includes the components of the composite deviation of the right and left tooth surfaces. Therefore, it is impossible to determine the single deviation of the tooth surface on the same side. The measurement of radial composite deviation can quickly provide information about quality defects caused by the clamping of production machines, tools or product gears. This method is mainly used for the detection of mass-produced gears and small-module gears. The composite deviation of one tooth that occurs for each pitch rotation helps to reveal the tooth profile deviation (usually the tooth profile tilt deviation). A large individual composite deviation of one tooth indicates a large pitch deviation or a damaged tooth (see Figure 6). After proper calibration of the clamping and detection methods of the product gears, this measurement process can also be used to determine the center distance of the minimum side clearance meshing of the product gears, see GB/Z18620.3 for recommendations on shaft center distance and axis parallelism. In addition, this step is also useful for detecting gears that need to run with minimum side clearance, because the range of functional tooth thickness can be easily obtained from the radial composite deviation. 6
YKAoNrKAca
To determine the accuracy grade:
GB/Z18620.2--2002
a) For spur gears, the product gears shall be tested with a measuring gear that can contact 100% of the effective tooth profile. See 5.5 of GB/T10095.2-2001. The tolerance values of the radial comprehensive total deviation and the radial comprehensive deviation of one tooth given in GB/T10095.2 are used to determine the accuracy grade of spur gears. It must be emphasized that because the tooth surfaces on both sides work at the same time, the accuracy grade obtained by double-sided meshing testing cannot be directly related to the accuracy grade obtained by testing with a single element. b) For helical gears, although the tolerances in GB/T10095.2 are for spur gears, they can also be used to evaluate helical gears if both the purchaser and the supplier agree. In this case, the overlap e8tes when meshing with the gear should meet the requirements of 4.1. Radial runout
This is the fluctuation of the center distance of the product gear in one revolution, which is shown as a slowly increasing and decreasing curve on the line graph (i.e. the gear ratio changes). Damaged teeth
Pitch deviation
On the line graph, the recording pen between two adjacent teeth appears suddenly and irregularly offset with varying amplitudes. Profile deviation
The smaller wave on the curve indicates the deviation between the tooth profile and the theoretical involute tooth profile, and each wave corresponds to the contact period of one tooth. 335
Pressure angle deviation (tooth profile inclination deviation)
They appear on the curve graph as regularly spaced and pointed vertical offsets, and each offset corresponds to the contact period of one tooth. Group. Explanation of radial combined deviation
5 Measurement of radial runout and determination of eccentricity 5.1 Principle of measurement
The radial runout F of a gear tooth is the difference between the maximum and minimum radial positions of a suitable probe (ball, anvil, cylinder or prism) placed in each tooth groove, tooth by tooth, relative to the reference axis of the gear when the gear rotates (see Figure 7). If a ball, cylinder or anvil is used to contact both sides of the tooth in the tooth groove, the tolerance table listed in Appendix B of GB/T10095.22001 can be applied. In some cases, a rider is used to contact both sides of the tooth, and the tolerance table is not intended to be used in this case. The diameter of the ball should be selected so that it can contact the middle part of the tooth groove and should be placed in the center of the tooth width (see 6.3 Calculation of ball diameter). 5.2 Dimensions of the anvil for measuring radial runout
The dimensions of the anvil should be chosen so that it contacts the tooth surface approximately at the pitch circle in the tooth groove. The half angle of the prism can be determined by the following approximation, where t, αy and n are the angles of contact on the measuring circle (see Figure 8). 7
GB/Z18620.2—2002
The anvil should contact the tooth surface at the center of the tooth width with a measuring circle of diameter d. Ball or cylinder
Anvil or prism
Figure 7 Principle of measuring radial runout
Oye ay + nye
cosayt
dcosat
Figure 8 Dimensions of the anvil for measuring radial runout
ikAoNrKAca
（9）
（10）1 requirement. Radial runout
This is the fluctuation of the center distance of the product gear in one revolution, which is shown as a slowly increasing and decreasing curve on the line graph (i.e. the gear ratio changes). Damaged teeth
Pitch deviation
On the line graph, the recording pen between two adjacent teeth shows a sudden and irregular offset with a varying amplitude. Profile deviation
The smaller wave on the curve indicates the deviation between the tooth profile and the theoretical involute tooth profile, and each waveform corresponds to a tooth contact cycle. 335
Pressure angle deviation (tooth profile inclination deviation)
They appear as regularly spaced and pointed vertical offsets on the curve graph, and each offset corresponds to a tooth contact cycle. Group. Explanation of radial combined deviation
5 Measurement of radial runout and determination of eccentricity 5.1 Principle of measurement
The radial runout F of a gear tooth is the difference between the maximum and minimum radial positions of a suitable probe (ball, anvil, cylinder or prism) placed in each tooth groove, tooth by tooth, relative to the reference axis of the gear when the gear rotates (see Figure 7). If a ball, cylinder or anvil is used to contact both sides of the tooth in the tooth groove, the tolerance table listed in Appendix B of GB/T10095.22001 can be applied. In some cases, a rider is used to contact both sides of the tooth, and the tolerance table is not intended to be used in this case. The diameter of the ball should be selected so that it can contact the middle part of the tooth groove and should be placed in the center of the tooth width (see 6.3 Calculation of ball diameter). 5.2 Dimensions of the anvil for measuring radial runout
The dimensions of the anvil should be chosen so that it contacts the tooth surface approximately at the pitch circle in the tooth groove. The half angle of the prism can be determined by the following approximation, where t, αy and n are the angles of contact on the measuring circle (see Figure 8). 7
GB/Z18620.2—2002
The anvil should contact the tooth surface at the center of the tooth width with a measuring circle of diameter d. Ball or cylinder
Anvil or prism
Figure 7 Principle of measuring radial runout
Oye ay + nye
cosayt
dcosat
Figure 8 Dimensions of the anvil for measuring radial runout
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（10）1 requirement. Radial runout
This is the fluctuation of the center distance of the product gear in one revolution, which is shown as a slowly increasing and decreasing curve on the line graph (i.e. the gear ratio changes). Damaged teeth
Pitch deviation
On the line graph, the recording pen between two adjacent teeth shows a sudden and irregular offset with a varying amplitude. Profile deviation
The smaller wave on the curve indicates the deviation between the tooth profile and the theoretical involute tooth profile, and each waveform corresponds to a tooth contact cycle. 335
Pressure angle deviation (tooth profile inclination deviation)
They appear as regularly spaced and pointed vertical offsets on the curve graph, and each offset corresponds to a tooth contact cycle. Group. Explanation of radial combined deviation
5 Measurement of radial runout and determination of eccentricity 5.1 Principle of measurement
The radial runout F of a gear tooth is the difference between the maximum and minimum radial positions of a suitable probe (ball, anvil, cylinder or prism) placed in each tooth groove, tooth by tooth, relative to the reference axis of the gear when the gear rotates (see Figure 7). If a ball, cylinder or anvil is used to contact both sides of the tooth in the tooth groove, the tolerance table listed in Appendix B of GB/T10095.22001 can be applied. In some cases, a rider is used to contact both sides of the tooth, and the tolerance table is not intended to be used in this case. The diameter of the ball should be selected so that it can contact the middle part of the tooth groove and should be placed in the center of the tooth width (see 6.3 Calculation of ball diameter). 5.2 Dimensions of the anvil for measuring radial runout
The dimensions of the anvil should be chosen so that it contacts the tooth surface approximately at the pitch circle in the tooth groove. The half angle of the prism can be determined by the following approximation, where t, αy and n are the angles of contact on the measuring circle (see Figure 8). 7
GB/Z18620.2—2002
The anvil should contact the tooth surface at the center of the tooth width with a measuring circle of diameter d. Ball or cylinder
Anvil or prism
Figure 7 Principle of measuring radial runout
Oye ay + nye
cosayt
dcosat
Figure 8 Dimensions of the anvil for measuring radial runout
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