Some standard content:
National Standard of the People's Republic of China
Bevel and hypoid gears
Accuracy of bevel and hypoid gears1 Subject content and scope of application
GB 113B5—89
This standard specifies the errors, definitions, codes, accuracy grades, tooth wear requirements, inspection and tolerances, backlash and drawing markings of bevel and hypoid gears and their gear pairs.
This standard is applicable to spur, helical and curved bevel gears and hypoid gears (hereinafter referred to as gears) with a midpoint normal module m>1mm.
When the gear specifications exceed the range listed in the table of this standard (midpoint normal module greater than 55mm, midpoint pitch circle diameter greater than 4000mm), it can be handled in accordance with the provisions of Appendix A (Supplement). 2 Reference standards
GB1800 General theory of tolerance and fit Standard tolerance and basic deviation 3 Definitions and codes
Definition and codes of gear, gear pair error and backlash (see Table 1) Table 1
Tangential comprehensive error
Tangential comprehensive tolerance
-Tooth tangential comprehensive error
-Tooth tangential comprehensive tolerance
Approved by the State Administration of Technical Supervision on May 6, 1989
When the measured gear is in single-sided meshing with the ideal and accurate measuring gear at the specified installation position, the total amplitude value of the difference between the actual rotation angle and the theoretical rotation angle within the measured gear rotation. Measured by the length of the dividing arc at the midpoint of the tooth width
When the measured gear is in single-sided meshing with the ideal and accurate measuring gear at the specified installation position, the maximum amplitude value of the difference between the actual rotation angle and the theoretical rotation angle within one pitch angle of the measured gear. Measured by the length of the dividing arc at the midpoint of the tooth width
1990-01-01Implementation
Axis angle comprehensive error
Axis angle comprehensive tolerance
-Axis angle comprehensive error
-Axis angle comprehensive tolerance
Periodic error
Tolerance of periodic error
Total pitch error
Total pitch tolerance
GB 11865—89
Continued Table 1
When the gear under test is double-sidedly engaged with the ideal and accurate measuring gear under the condition that the dividing cone points coincide, the maximum change of the gear countershaft angle within one rotation of the gear under test is recorded. Measured by the line value at the midpoint of the tooth widthWhen the gear under test is double-sidedly engaged with the ideal and accurate measuring gear under the condition that the dividing cone apex coincides, the maximum change of the gear countershaft angle within the gear under test~pitch angle. When the measured gear is single-sidedly engaged with the ideal and accurate measuring gear according to the specified installation position, the total amplitude value of the measured gear for two times (including two times) or more within one rotation of the measured gear is measured at the line value at the midpoint of the tooth width. The maximum absolute value of the difference between the actual arc length and the nominal arc length between the two tooth surfaces on the same side is measured at the midpoint graduation reading 1". K tooth pitch cumulative error
K tooth pitch cumulative tolerance
gear ring runout ,
Gear ring runout tolerance
Tooth pitch deviation
Actual pitch
Nominal gear
Tooth pitch limit deviation
Upper deviation
Lower deviation
Tooth profile error
Tolerance of tooth profile relative error
Tooth thickness deviation
Tooth thickness limit deviation
Upper deviation
Lower deviation
GB 11365—89
Continued Table 1
The maximum absolute value of the difference between the actual arc length and the nominal arc length of K pitches on the midpoint pitch circle. K is an integer from 2 to less than Z/2
Within one gear rotation range, when the probe is in double contact with the middle of the tooth surface in the tooth sill, the maximum change in the pitch along the pitch cone relative to the gear axis
The difference between the actual pitch and the nominal pitch on the midpoint pitch circle
When the gear rotates around the axis, the difference in the angle of motion transmitted by the actual tooth surface of each gear tooth relative to the reference actual tooth surface. The actual tooth thickness at the midpoint of the tooth width is calculated based on the line value at the midpoint of the tooth width. Difference between value and nominal value
Gear pair tangential comprehensive error
Gear pair tangential comprehensive tolerance
Gear pair tooth tangential comprehensive error
Gear pair one tooth tangential comprehensive tolerance
Gear pair shaft angle comprehensive error
Gear pair shaft angle comprehensive tolerance
Gear pair one gear shaft angle comprehensive error
Gear pair one gear shaft angle comprehensive tolerance
Gear pair periodic error
Gear pair periodic error tolerance
Gear pair tooth frequency periodic error
Gear pair tooth periodic error tolerance
GB 1186689
Continued Table 1
When the gear pair is single-sided meshed at the specified installation position, the total amplitude value of the difference between the actual rotation angle of one gear relative to the other gear and the theoretical rotation angle within the entire rotation cycle\. Measured by the length of the dividing arc at the midpoint of the tooth width
When the gear pair is single-sided meshed at the specified installation position, the maximum value of the difference between the actual rotation angle of one gear relative to the other gear within a pitch angle. Take the value within the entire cycle", measure the length of the dividing arc at the midpoint of the tooth width
When the gear pair is double-sided meshed under the condition that the points of the dividing cone coincide, the maximum change of the shaft angle within the entire rotation cycle. Measured by the line value at the midpoint of the tooth width
When the gear pair is double-sided meshed under the condition that the points of the dividing cone coincide, the maximum change of the shaft angle within a pitch angle. The value is taken within the whole cycle, and the line value at the midpoint of the tooth width is used for calculation.
When the gear pair is in single-sided meshing at the specified installation position, within the range of one rotation of the large wheel, the total amplitude value of the harmonics above the second order (including the second order) When the gear pair is in single-sided meshing at the specified installation position, the total amplitude value of the harmonics with the number of teeth as the frequency. Serial number
Contact spot
Gear profile clearance
[Circular
AA Court rotation
GBF1865—89
Continued Table 1
Contact traces obtained on the working tooth surface of the gear after the installed gear pair (or the gear to be tested and the gear to be measured) are operated under slight braking. The contact spot includes three requirements: shape, position, and size.
The size of the contact decay trace is determined by percentage: along the tooth length direction
Contact trace length
×10 0%, the ratio of
to the upper working length is the ratio of the
contact trace height h" along the tooth height direction to the working tooth height h in the middle of the
contact trace, that is, h
×100%
After the gear pair is tightly installed, when one gear is fixed, the length of the dividing arc of the tooth width midpoint that the other gear rotates from the working tooth surface contact to the non-working tooth surface contact is ||t t||Normal backlash
C rotation
Minimum circumferential backlash
Maximum circumferential backlash
Minimum normal backlash
Maximum normal backlash
Gear pair backlash variation
Gear pair backlash variation tolerance
Gear figure axial displacement
Gear ring axial displacement limit deviation
Upper deviation
Lower deviation
GB 11*66 --a body
Continued Table 1
it mar
After the gear pair is installed in the specified position, when the working tooth surfaces are in contact, the minimum distance between the non-working tooth surfaces. Measured at the midpoint of the tooth width
i.=jicosβcosa
After the gear pair is installed in the specified position, within the "full cycle of rotation", the difference between the maximum and minimum values of the normal clearance
After the gear is assembled, the axial displacement of the gear ring relative to the best meshing position determined on the hydraulic inspection machine
Moment deviation between gear countershafts
Design axis
Limit deviation of gear countershaft spacing
Upper deviation
Lower deviation
Angle deviation of gear countershafts
Limit deviation of gear countershaft angle
Upper deviation
Lower deviation
Note: 1) Measurement is allowed in the middle of the tooth surface.
GB 11365—89
Continued Table 1
Design succession
Actual axis
2) The full rotation period of the gear pair is calculated as follows: n2=2
The difference between the actual axis distance of the gear pair and the nominal axis distance and the actual axis angle of the gear pair and the nominal axis angle. Calculated by the line value at the midpoint of the tooth width
Where: n2——number of revolutions of the large wheel, 7,——number of teeth of the small wheel, X—greatest common divisor of the number of teeth of the large and small wheels. Accuracy level
4.1 This standard specifies 12 accuracy levels for gears and gear pairs. Level 1 has the highest accuracy and level 12 has the lowest accuracy. 4.2 The tolerance items of gears and gear pairs are divided into three tolerance groups: Fi.F\s-Fp.Fpk.FI
Gear of tolerance group I
Gear pair Fi., Fise, F
Gear of tolerance group II, z, fz, fpt, f. Gear pair fiefizefzkefzzc, fam
Gear contact spot of tolerance group III
Gear contact spot f.
4.3 According to the use requirements, different accuracy grades are allowed for each tolerance group. However, the same accuracy grade should be specified for the same tolerance group of the middle and small gears of the gear pair.
4.4 Different accuracy grades are allowed for the working tooth surface and the non-working tooth surface (except Fs, Fz, fiz, Fis, Ft, Fv). 5 Tooth wear requirements
GB 11365-89
5.1 The positioning reference surface of the gear during the inspection and installation should be as consistent as possible. And it should be marked on the gear part drawing. 5.2 This standard recommends the use of the tooth tolerance in Appendix B (reference part). 6 Gear inspection and tolerance
6.1 According to the working requirements of the gear and the production scale, select one inspection group from the following tolerance groups to evaluate and accept the accuracy level of the gear. The inspection group can be determined by negotiation between the supplier and the buyer. Inspection group of tolerance group I
4F: (for 4 to 8 levels of accuracy) 1
△F: (for 7 to 12 levels of accuracy straight bevel gears for 9 to 12 levels of accuracy residual teeth, curved bevel gears)! F and △Fp (for 4 to 6 levels of accuracy)
△F. (for 7 to 8 levels of accuracy)
4F, (for 7 to 12 levels of accuracy, of which 7 to 8 levels are used for gears with a midpoint pitch circle diameter of less than 1600mm). Test group of tolerance group II
f (for 4 to 8 grades of accuracy)
A (for 7 to 12 grades of accuracy of straight bevel gears, 9 to 12 grades of accuracy of helical gears, curved bevel gears), A/z (for 4 to 8 grades of accuracy, longitudinal overlap greater than the limit value in Table 2) Afpt and Af. (for 4 to 6 grades of accuracy) △fp (for 7 to 12 grades of accuracy).
Test group of tolerance group III
Contact spot.
Precision grade of tolerance group III
Longitudinal overlap 8 limit value
6.2 The tolerance values of various accuracy grades and various inspection items of gears are specified as follows: 8
6.2.1Fi, F12, f, as specified in A1 of Appendix A. 6.2.2Fp, Fpk are specified in Table 3, F, are specified in Table 4: k is specified in Table 5: ±fg is specified in Table 6, f is specified in Table 7.
6.2.3 The shape, position and size of the contact spot shall be specified by the designer according to the purpose of the gear, load, gear tooth rigidity and tooth line shape characteristics. For gears with modified tooth surface, no contact points are allowed at the large end, small end and tooth top edge of the tooth surface. The relationship between the size of the contact spot and the accuracy grade listed in Table B4 of Appendix B is for reference. 7 Inspection and tolerance of gear pairs
7.1 The accuracy of gear pairs includes four requirements: I, II, II tolerance groups and side clearance. When the gear pair is installed on the actual device, the installation errors Aja, Afa and AE should be inspected.
7.2 According to the working requirements and production scale of the gear pair, one inspection group is selected from the following tolerance groups to evaluate and accept the accuracy of the gear pair. The inspection group can be determined by the supply and demand parties of the order. The inspection group of the first tolerance group
AF (for 4~8 grade accuracy)
AF. (for 7~12 grade accuracy straight bevel gear pairs, for 9~12 grade slightly helical gear. Curved bevel gear pairs) 4F (for ~12 grade accuracy)
Inspection group of the second tolerance group
Af (for 4~8 grade accuracy)
GB11365-89
△. (for 7~12 grade accuracy straight bevel gear pairs, for 9~12 grade accuracy helical gear and curved bevel gear pairs) 4/zkc (for 4~8 grade accuracy, longitudinal overlap e greater than or equal to the limit value in Table 2)/△fzz (for 4~8 grade accuracy, longitudinal overlap es less than the limit value in Table 2). Inspection group of the third tolerance group
Contact spot.
7.a For each accuracy grade, the tolerances of various inspection items of gear pairs are stipulated as follows: 7.3.1 Fic and fic are stipulated in A2 and A2.1 in Appendix A. 7.3.2 fc is stipulated in Table 5, Fizc is stipulated in Table 8, F is stipulated in Table 9; fis is stipulated in Table 10, and fzz is stipulated in Table I1. 7.3.3 The provisions of contact spots are shown in 6.2.3. 7.8.4 ±fAM, ±f, ±E are stipulated in Tables 16, 17, and 18 respectively. 8 Gear pair backlash
8.1 The standard stipulates that there are 6 types of minimum normal backlash of gear pairs: a, b, c, d, e and h. The minimum normal backlash value is the largest when a is the maximum and h is zero (as shown in the figure below). The type of minimum normal backlash is particularly related to the accuracy grade. h
8.2 After the minimum normal backlash type is determined, Es and ±E2 are obtained according to Table 13 and Table 18. 8.a The minimum normal backlash iam is specified in Table 12. When there are special requirements, 7amin may not be determined according to the values listed in Table 12. In this case, E and ±Es are calculated from Table 13 and Table 18 using the linear interpolation method. 8.4 The maximum normal backlash nm is specified as max = ([E1 +Es2/+T+T2+E^1+2)cos. E is the compensation part of the manufacturing error, which can be obtained from Table 15. 8.5 This standard specifies five types of normal backlash tolerances for gear pairs: A, B, C, D and H. The normal backlash tolerance type is related to the accuracy grade. Different types of normal backlash tolerances and minimum normal backlash combinations are allowed. In general, the corresponding relationship between the recommended normal backlash tolerance type and the minimum normal backlash type is shown in the figure. 8.6 The tooth thickness tolerance T shall be in accordance with Table 14.
9 Drawing marking
9.1 The gear working drawing L shall be marked with the numerical (letter) code of the gear accuracy grade and the minimum normal backlash type and the normal backlash tolerance type.
Marking example
GB 11365—89
The three tolerance groups of gears have the same accuracy of 7, the minimum normal backlash type is b, and the normal backlash tolerance type is 8:7
GB11365
Minimum normal backlash and normal backlash tolerance type Accuracy grade of tolerance groups I, II, and III
The two tolerance groups of gears have the same accuracy of 7, the minimum normal backlash is 400μⅢ, and the normal backlash tolerance type is B:9.1.2
GB 11365
Normal backlash tolerance type
Minimum normal backlash value
Accuracy grades of tolerance groups I, II and III
9.1.3 The accuracy of tolerance group I of gears is grade 8, the accuracy of tolerance groups II and III is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance type
Minimum normal backlash type
Accuracy grade of tolerance group III
Accuracy grade of tolerance group II
Accuracy grade of tolerance group I
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade4 Different accuracy grades are allowed for working tooth surface and non-working tooth surface (except Fs, Fz, fiz, Fis, Ft, Fv). 5 Tooth wear requirements
GB 11365-89
5.1 The positioning reference surface of the gear during the inspection and installation should be as consistent as possible. And it should be marked on the gear part drawing. 5.2 This standard recommends the use of the tooth wear tolerance in Appendix B (reference part). 6 Gear inspection and tolerance
6.1 According to the working requirements and production scale of the gear, select one inspection group from the following tolerance groups to evaluate and accept the accuracy grade of the gear. The inspection group can be determined by negotiation between the supply and demand parties of the order. Inspection group of tolerance group I
4F: (for 4 to 8 grades of accuracy)1
△F: (for 7 to 12 grades of accuracy of straight bevel gears, for 9 to 12 grades of accuracy of residual teeth and curved bevel gears)! F and △Fp (for 4~6 grade accuracy)
△F. (for 7~8 grade accuracy)
4F, (for 7~12 grade accuracy, where 7~8 grade is used for gears with a midpoint pitch circle diameter of less than 1600mm). Inspection group of tolerance group II
f (for 4~8 grade accuracy)
A (for spur bevel gears with 7~12 grade accuracy, and helical and curved bevel gears with 9~12 grade accuracy), A/z (for gears with 4~8 grade accuracy and longitudinal overlap greater than the limit value in Table 2) Afpt and Af. (for 4~6 grade accuracy) △fp (for 7~12 grade accuracy).
Inspection group of tolerance group III
Contact spot.
The second tolerance group precision grade
Longitudinal overlap 8 limit value
6.2 The tolerance values of each precision grade and each gear inspection item are specified as follows,8
6.2.1Fi, F12, f, as specified in A1 of Appendix A. 6.2.2Fp, Fpk as specified in Table 3, F, as specified in Table 4: k as specified in 5: ±fg as specified in Table 6, f as specified in Table ?.
6.2.3 The shape, position and size of the contact spot shall be specified by the designer according to the purpose of the gear, load, gear tooth rigidity and tooth line shape characteristics. For gears with modified tooth surface, contact points are not allowed to appear at the big end, small end and tooth top edge of the tooth surface. The relationship between the size of the contact spot and the precision grade listed in Table B4 of Appendix B is for reference. 7 Inspection and tolerance of gear pair
7.1 The accuracy of gear pair includes four requirements: tolerance group I, II, II and backlash. When the gear pair is installed on the actual device, the installation error Aja, Afa and AE should be inspected.
7.2 According to the working requirements and production scale of the gear pair, one inspection group is selected from the following tolerance groups to evaluate and accept the accuracy of the gear pair. The inspection group can be determined by the supplier and the demander of the order. Inspection group of the first tolerance group
AF (for 4 to 8 grade accuracy)
AF. (for 7 to 12 grade accuracy straight bevel gear pairs, for 9 to 12 grade slightly helical bevel gear pairs)
Inspection group of the second tolerance group
Af (for 4 to 8 grade accuracy)
GB11365-89
△ (For straight-cone gear pairs with accuracy levels 7 to 12, and for helical and curved bevel gear pairs with accuracy levels 9 to 12) 4/zkc (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap e greater than or equal to the limit value in Table 2) /△fzz (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap es less than the limit value in Table 2). Inspection group of tolerance group III
Contact spots.
7.a For each accuracy level, the tolerance numbers of various inspection items of gear pairs are as follows: 7.3.1 Fic and fic are as specified in A2 and A2.1 in Appendix A. 7.3.2 fc is as specified in Table 5, Fizc is as specified in Table 8, and F is as specified in Table 9; fis is as specified in Table 10, and fzz is as specified in Table I1. 7.3.3 The provisions of contact spots are as specified in 6.2.3. 7.8.4 ±fAM, ±f, ±E are as specified in Tables 16, 17, and 18 respectively. 8 Gear pair backlash
8.1 The standard stipulates that there are 6 types of minimum normal backlash of gear pairs: a, b, c, d, e and h. The minimum normal backlash value is the maximum with a and zero with h (as shown in the figure below). The minimum normal backlash type is particularly related to the accuracy grade. h
8.2 After the minimum normal backlash type is determined, Es and ±E2 are obtained according to Table 13 and Table 18. 8.a The minimum normal backlash iam is specified in Table 12. When there are special requirements, 7amin may not be determined according to the values listed in Table 12. At this time, E and ±Es are calculated from Table 13 and Table 18 using linear interpolation. 8.4 The maximum normal backlash nm is specified as max = ([E1 +Es2/+T+T2+E^1+2)cos. E is the compensation part of the manufacturing error, which can be obtained from Table 15. 8.5 This standard specifies five types of normal backlash tolerances for gear pairs: A, B, C, D and H. The type of normal backlash tolerance is related to the accuracy grade. Different types of normal backlash tolerances and minimum normal backlash combinations are allowed. In general, the recommended correspondence between the normal backlash tolerance type and the minimum normal backlash type is shown in the figure. 8.6 The tooth thickness tolerance T is specified in Table 14.
9 Drawing marking
9.1 The gear working drawing L should be marked with the numerical (letter) code of the gear accuracy grade and the minimum normal backlash type and the normal backlash tolerance type.
Marking example
GB 11365—89
The three tolerance groups of gears have the same accuracy of 7, the minimum normal backlash type is b, and the normal backlash tolerance type is 8:7
GB11365
Minimum normal backlash and normal backlash tolerance type Accuracy grades of tolerance groups I, II, and III
The two tolerance groups of gears have the same accuracy of 7, the minimum normal backlash is 400μⅢ, and the normal backlash tolerance type is B:9.1.2
GB 11365
Normal backlash tolerance type
Minimum normal backlash value
Accuracy grades of tolerance groups I, II and III
9.1.3 The accuracy of tolerance group I of gears is grade 8, the accuracy of tolerance groups II and III is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance type
Minimum normal backlash type
Accuracy grade of tolerance group III
Accuracy grade of tolerance group II
Accuracy grade of tolerance group I
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade4 Different accuracy grades are allowed for working tooth surface and non-working tooth surface (except Fs, Fz, fiz, Fis, Ft, Fv). 5 Tooth wear requirements
GB 11365-89
5.1 The positioning reference surface of the gear during the inspection and installation should be as consistent as possible. And it should be marked on the gear part drawing. 5.2 This standard recommends the use of the tooth wear tolerance in Appendix B (reference part). 6 Gear inspection and tolerance
6.1 According to the working requirements and production scale of the gear, select one inspection group from the following tolerance groups to evaluate and accept the accuracy grade of the gear. The inspection group can be determined by negotiation between the supply and demand parties of the order. Inspection group of tolerance group I
4F: (for 4 to 8 grades of accuracy)1
△F: (for 7 to 12 grades of accuracy of straight bevel gears, for 9 to 12 grades of accuracy of residual teeth and curved bevel gears)! F and △Fp (for 4~6 grade accuracy)
△F. (for 7~8 grade accuracy)
4F, (for 7~12 grade accuracy, where 7~8 grade is used for gears with a midpoint pitch circle diameter of less than 1600mm). Inspection group of tolerance group II
f (for 4~8 grade accuracy)
A (for spur bevel gears with 7~12 grade accuracy, and helical and curved bevel gears with 9~12 grade accuracy), A/z (for gears with 4~8 grade accuracy and longitudinal overlap greater than the limit value in Table 2) Afpt and Af. (for 4~6 grade accuracy) △fp (for 7~12 grade accuracy).
Inspection group of tolerance group III
Contact spot.
The second tolerance group precision grade
Longitudinal overlap 8 limit value
6.2 The tolerance values of each precision grade and each gear inspection item are specified as follows,8
6.2.1Fi, F12, f, as specified in A1 of Appendix A. 6.2.2Fp, Fpk as specified in Table 3, F, as specified in Table 4: k as specified in 5: ±fg as specified in Table 6, f as specified in Table ?.
6.2.3 The shape, position and size of the contact spot shall be specified by the designer according to the purpose of the gear, load, gear tooth rigidity and tooth line shape characteristics. For gears with modified tooth surface, contact points are not allowed to appear at the big end, small end and tooth top edge of the tooth surface. The relationship between the size of the contact spot and the precision grade listed in Table B4 of Appendix B is for reference. 7 Inspection and tolerance of gear pair
7.1 The accuracy of gear pair includes four requirements: tolerance group I, II, II and backlash. When the gear pair is installed on the actual device, the installation error Aja, Afa and AE should be inspected.
7.2 According to the working requirements and production scale of the gear pair, one inspection group is selected from the following tolerance groups to evaluate and accept the accuracy of the gear pair. The inspection group can be determined by the supplier and the demander of the order. Inspection group of the first tolerance group
AF (for 4 to 8 grade accuracy)
AF. (for 7 to 12 grade accuracy straight bevel gear pairs, for 9 to 12 grade slightly helical bevel gear pairs)
Inspection group of the second tolerance group
Af (for 4 to 8 grade accuracy)
GB11365-89
△ (For straight-cone gear pairs with accuracy levels 7 to 12, and for helical and curved bevel gear pairs with accuracy levels 9 to 12) 4/zkc (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap e greater than or equal to the limit value in Table 2) /△fzz (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap es less than the limit value in Table 2). Inspection group of tolerance group III
Contact spots.
7.a For each accuracy level, the tolerance numbers of various inspection items of gear pairs are as follows: 7.3.1 Fic and fic are as specified in A2 and A2.1 in Appendix A. 7.3.2 fc is as specified in Table 5, Fizc is as specified in Table 8, and F is as specified in Table 9; fis is as specified in Table 10, and fzz is as specified in Table I1. 7.3.3 The provisions of contact spots are as specified in 6.2.3. 7.8.4 ±fAM, ±f, ±E are as specified in Tables 16, 17, and 18 respectively. 8 Gear pair backlash
8.1 The standard stipulates that there are 6 types of minimum normal backlash of gear pairs: a, b, c, d, e and h. The minimum normal backlash value is the maximum with a and zero with h (as shown in the figure below). The minimum normal backlash type is particularly related to the accuracy grade. h
8.2 After the minimum normal backlash type is determined, Es and ±E2 are obtained according to Table 13 and Table 18. 8.a The minimum normal backlash iam is specified in Table 12. When there are special requirements, 7amin may not be determined according to the values listed in Table 12. At this time, E and ±Es are calculated from Table 13 and Table 18 using linear interpolation. 8.4 The maximum normal backlash nm is specified as max = ([E1 +Es2/+T+T2+E^1+2)cos. E is the compensation part of the manufacturing error, which can be obtained from Table 15. 8.5 This standard specifies five types of normal backlash tolerances for gear pairs: A, B, C, D and H. The type of normal backlash tolerance is related to the accuracy grade. Different types of normal backlash tolerances and minimum normal backlash combinations are allowed. In general, the recommended correspondence between the normal backlash tolerance type and the minimum normal backlash type is shown in the figure. 8.6 The tooth thickness tolerance T is specified in Table 14.
9 Drawing marking
9.1 The gear working drawing L should be marked with the numerical (letter) code of the gear accuracy grade and the minimum normal backlash type and the normal backlash tolerance type.
Marking example
GB 11365—89
The three tolerance groups of gears have the same accuracy of 7, the minimum normal backlash type is b, and the normal backlash tolerance type is 8:7
GB11365
Minimum normal backlash and normal backlash tolerance type Accuracy grades of tolerance groups I, II, and III
The two tolerance groups of gears have the same accuracy of 7, the minimum normal backlash is 400μⅢ, and the normal backlash tolerance type is B:9.1.2
GB 11365
Normal backlash tolerance type
Minimum normal backlash value
Accuracy grades of tolerance groups I, II and III
9.1.3 The accuracy of tolerance group I of gears is grade 8, the accuracy of tolerance groups II and III is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance typewww.bzxz.net
Minimum normal backlash type
Accuracy grade of tolerance group III
Accuracy grade of tolerance group II
Accuracy grade of tolerance group I
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade(For 4 to 8 grades of accuracy) 1
△F: (For 7 to 12 grades of accuracy of straight bevel gears, for 9 to 12 grades of accuracy of residual teeth, curved bevel gears)! F and △Fp (For 4 to 6 grades of accuracy)
△F. (Using 7 to 8 grades of accuracy)
4F, (For 7 to 12 grades of accuracy, where 7 to 8 grades are used for gears with a midpoint pitch circle diameter greater than 1600mm). Inspection group of tolerance group II
f (For 4 to 8 grades of accuracy)
A (For 7 to 12 grades of accuracy of straight bevel gears, for 9 to 12 grades of accuracy of helical teeth, curved bevel gears), A/z (For 4 to 8 grades of accuracy, gears with longitudinal overlap greater than the limit value in Table 2) Afpt and Af. (Using 4 to 6 grades of accuracy) △fp (For 7 to 12 grades of accuracy).
Test group of tolerance group III
Contact spot.
Precision grade of tolerance group II
Longitudinal overlap 8 Limit value
6.2 The tolerance values of various precision grades and various inspection items of gears are specified as follows: 8
6.2.1Fi, F12, f, shall be specified in A1 of Appendix A. 6.2.2Fp, Fpk shall be specified in Table 3, F, shall be specified in Table 4: k shall be specified in Table 5: ±fg shall be specified in Table 6, and f shall be specified in Table ?.
6.2.3 The shape, position and size of the contact spot shall be specified by the designer according to the purpose of the gear, load, gear tooth rigidity and tooth line shape characteristics. For gears with modified tooth surface, contact points are not allowed to appear at the big end, small end and tooth top edge of the tooth surface. The relationship between the size of the contact spot and the precision grade listed in Table B4 of Appendix B is for reference. 7 Inspection and tolerance of gear pair
7.1 The accuracy of gear pair includes four requirements: tolerance group I, II, II and backlash. When the gear pair is installed on the actual device, the installation error Aja, Afa and AE should be inspected.
7.2 According to the working requirements and production scale of the gear pair, one inspection group is selected from the following tolerance groups to evaluate and accept the accuracy of the gear pair. The inspection group can be determined by the supplier and the demander of the order. Inspection group of the first tolerance group
AF (for 4 to 8 grade accuracy)
AF. (for 7 to 12 grade accuracy straight bevel gear pairs, for 9 to 12 grade slightly helical bevel gear pairs)
Inspection group of the second tolerance group
Af (for 4 to 8 grade accuracy)
GB11365-89
△ (For straight-cone gear pairs with accuracy levels 7 to 12, and for helical and curved bevel gear pairs with accuracy levels 9 to 12) 4/zkc (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap e greater than or equal to the limit value in Table 2) /△fzz (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap es less than the limit value in Table 2). Inspection group of tolerance group III
Contact spots.
7.a For each accuracy level, the tolerance numbers of various inspection items of gear pairs are as follows: 7.3.1 Fic and fic are as specified in A2 and A2.1 in Appendix A. 7.3.2 fc is as specified in Table 5, Fizc is as specified in Table 8, and F is as specified in Table 9; fis is as specified in Table 10, and fzz is as specified in Table I1. 7.3.3 The provisions of contact spots are as specified in 6.2.3. 7.8.4 ±fAM, ±f, ±E are as specified in Tables 16, 17, and 18 respectively. 8 Gear pair backlash
8.1 The standard stipulates that there are 6 types of minimum normal backlash of gear pairs: a, b, c, d, e and h. The minimum normal backlash value is the maximum with a and zero with h (as shown in the figure below). The minimum normal backlash type is particularly related to the accuracy grade. h
8.2 After the minimum normal backlash type is determined, Es and ±E2 are obtained according to Table 13 and Table 18. 8.a The minimum normal backlash iam is specified in Table 12. When there are special requirements, 7amin may not be determined according to the values listed in Table 12. At this time, E and ±Es are calculated from Table 13 and Table 18 using linear interpolation. 8.4 The maximum normal backlash nm is specified as max = ([E1 +Es2/+T+T2+E^1+2)cos. E is the compensation part of the manufacturing error, which can be obtained from Table 15. 8.5 This standard specifies five types of normal backlash tolerances for gear pairs: A, B, C, D and H. The type of normal backlash tolerance is related to the accuracy grade. Different types of normal backlash tolerances and minimum normal backlash combinations are allowed. In general, the recommended correspondence between the normal backlash tolerance type and the minimum normal backlash type is shown in the figure. 8.6 The tooth thickness tolerance T is specified in Table 14.
9 Drawing marking
9.1 The gear working drawing L should be marked with the numerical (letter) code of the gear accuracy grade and the minimum normal backlash type and the normal backlash tolerance type.
Marking example
GB 11365—89
The three tolerance groups of gears have the same accuracy of 7, the minimum normal backlash type is b, and the normal backlash tolerance type is 8:7
GB11365
Minimum normal backlash and normal backlash tolerance type Accuracy grades of tolerance groups I, II, and III
The two tolerance groups of gears have the same accuracy of 7, the minimum normal backlash is 400μⅢ, and the normal backlash tolerance type is B:9.1.2
GB 11365
Normal backlash tolerance type
Minimum normal backlash value
Accuracy grades of tolerance groups I, II and III
9.1.3 The accuracy of tolerance group I of gears is grade 8, the accuracy of tolerance groups II and III is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance type
Minimum normal backlash type
Accuracy grade of tolerance group III
Accuracy grade of tolerance group II
Accuracy grade of tolerance group I
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade(For 4 to 8 grades of accuracy) 1
△F: (For 7 to 12 grades of accuracy of straight bevel gears, for 9 to 12 grades of accuracy of residual teeth, curved bevel gears)! F and △Fp (For 4 to 6 grades of accuracy)
△F. (Using 7 to 8 grades of accuracy)
4F, (For 7 to 12 grades of accuracy, where 7 to 8 grades are used for gears with a midpoint pitch circle diameter greater than 1600mm). Inspection group of tolerance group II
f (For 4 to 8 grades of accuracy)
A (For 7 to 12 grades of accuracy of straight bevel gears, for 9 to 12 grades of accuracy of helical teeth, curved bevel gears), A/z (For 4 to 8 grades of accuracy, gears with longitudinal overlap greater than the limit value in Table 2) Afpt and Af. (Using 4 to 6 grades of accuracy) △fp (For 7 to 12 grades of accuracy).
Test group of tolerance group III
Contact spot.
Precision grade of tolerance group II
Longitudinal overlap 8 Limit value
6.2 The tolerance values of various precision grades and various inspection items of gears are specified as follows: 8
6.2.1Fi, F12, f, shall be specified in A1 of Appendix A. 6.2.2Fp, Fpk shall be specified in Table 3, F, shall be specified in Table 4: k shall be specified in Table 5: ±fg shall be specified in Table 6, and f shall be specified in Table ?.
6.2.3 The shape, position and size of the contact spot shall be specified by the designer according to the purpose of the gear, load, gear tooth rigidity and tooth line shape characteristics. For gears with modified tooth surface, contact points are not allowed to appear at the big end, small end and tooth top edge of the tooth surface. The relationship between the size of the contact spot and the precision grade listed in Table B4 of Appendix B is for reference. 7 Inspection and tolerance of gear pair
7.1 The accuracy of gear pair includes four requirements: tolerance group I, II, II and backlash. When the gear pair is installed on the actual device, the installation error Aja, Afa and AE should be inspected.
7.2 According to the working requirements and production scale of the gear pair, one inspection group is selected from the following tolerance groups to evaluate and accept the accuracy of the gear pair. The inspection group can be determined by the supplier and the demander of the order. Inspection group of the first tolerance group
AF (for 4 to 8 grade accuracy)
AF. (for 7 to 12 grade accuracy straight bevel gear pairs, for 9 to 12 grade slightly helical bevel gear pairs)
Inspection group of the second tolerance group
Af (for 4 to 8 grade accuracy)
GB11365-89
△ (For straight-cone gear pairs with accuracy levels 7 to 12, and for helical and curved bevel gear pairs with accuracy levels 9 to 12) 4/zkc (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap e greater than or equal to the limit value in Table 2) /△fzz (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap es less than the limit value in Table 2). Inspection group of tolerance group III
Contact spots.
7.a For each accuracy level, the tolerance numbers of various inspection items of gear pairs are as follows: 7.3.1 Fic and fic are as specified in A2 and A2.1 in Appendix A. 7.3.2 fc is as specified in Table 5, Fizc is as specified in Table 8, and F is as specified in Table 9; fis is as specified in Table 10, and fzz is as specified in Table I1. 7.3.3 The provisions of contact spots are as specified in 6.2.3. 7.8.4 ±fAM, ±f, ±E are as specified in Tables 16, 17, and 18 respectively. 8 Gear pair backlash
8.1 The standard stipulates that there are 6 types of minimum normal backlash of gear pairs: a, b, c, d, e and h. The minimum normal backlash value is the maximum with a and zero with h (as shown in the figure below). The minimum normal backlash type is particularly related to the accuracy grade. h
8.2 After the minimum normal backlash type is determined, Es and ±E2 are obtained according to Table 13 and Table 18. 8.a The minimum normal backlash iam is specified in Table 12. When there are special requirements, 7amin may not be determined according to the values listed in Table 12. At this time, E and ±Es are calculated from Table 13 and Table 18 using linear interpolation. 8.4 The maximum normal backlash nm is specified as max = ([E1 +Es2/+T+T2+E^1+2)cos. E is the compensation part of the manufacturing error, which can be obtained from Table 15. 8.5 This standard specifies five types of normal backlash tolerances for gear pairs: A, B, C, D and H. The type of normal backlash tolerance is related to the accuracy grade. Different types of normal backlash tolerances and minimum normal backlash combinations are allowed. In general, the recommended correspondence between the normal backlash tolerance type and the minimum normal backlash type is shown in the figure. 8.6 The tooth thickness tolerance T is specified in Table 14.
9 Drawing marking
9.1 The gear working drawing L should be marked with the numerical (letter) code of the gear accuracy grade and the minimum normal backlash type and the normal backlash tolerance type.
Marking example
GB 11365—89
The three tolerance groups of gears have the same accuracy of 7, the minimum normal backlash type is b, and the normal backlash tolerance type is 8:7
GB11365
Minimum normal backlash and normal backlash tolerance type Accuracy grades of tolerance groups I, II, and III
The two tolerance groups of gears have the same accuracy of 7, the minimum normal backlash is 400μⅢ, and the normal backlash tolerance type is B:9.1.2
GB 11365
Normal backlash tolerance type
Minimum normal backlash value
Accuracy grades of tolerance groups I, II and III
9.1.3 The accuracy of tolerance group I of gears is grade 8, the accuracy of tolerance groups II and III is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance type
Minimum normal backlash type
Accuracy grade of tolerance group III
Accuracy grade of tolerance group II
Accuracy grade of tolerance group I
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade2 According to the working requirements and production scale of the gear pair, select one inspection group from the following tolerance groups to evaluate and accept the accuracy of the gear pair. The inspection group can be determined by the supply and demand parties of the order. Inspection group of the first tolerance group
AF (for 4 to 8 grade accuracy)
AF. (for 7 to 12 grade accuracy straight bevel gear pairs, for 9 to 12 grade slightly helical bevel gear pairs)
Inspection group of the second tolerance group
Af (for 4 to 8 grade accuracy)
GB11365-89
△. (For straight-cone gear pairs with accuracy levels 7 to 12, and for helical and curved bevel gear pairs with accuracy levels 9 to 12) 4/zkc (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap e greater than or equal to the limit value in Table 2) /△fzz (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap es less than the limit value in Table 2). Inspection group of tolerance group III
Contact spots.
7.a For each accuracy level, the tolerance numbers of various inspection items of gear pairs are as follows: 7.3.1 Fic and fic are as specified in A2 and A2.1 in Appendix A. 7.3.2 fc is as specified in Table 5, Fizc is as specified in Table 8, and F is as specified in Table 9; fis is as specified in Table 10, and fzz is as specified in Table I1. 7.3.3 The provisions of contact spots are as specified in 6.2.3. 7.8.4 ±fAM, ±f, ±E are as specified in Tables 16, 17, and 18 respectively. 8 Gear pair backlash
8.1 The standard stipulates that there are 6 types of minimum normal backlash of gear pairs: a, b, c, d, e and h. The minimum normal backlash value is the maximum with a and zero with h (as shown in the figure below). The minimum normal backlash type is particularly related to the accuracy grade. h
8.2 After the minimum normal backlash type is determined, Es and ±E2 are obtained according to Table 13 and Table 18. 8.a The minimum normal backlash iam is specified in Table 12. When there are special requirements, 7amin may not be determined according to the values listed in Table 12. At this time, E and ±Es are calculated from Table 13 and Table 18 using linear interpolation. 8.4 The maximum normal backlash nm is specified as max = ([E1 +Es2/+T+T2+E^1+2)cos. E is the compensation part of the manufacturing error, which can be obtained from Table 15. 8.5 This standard specifies five types of normal backlash tolerances for gear pairs: A, B, C, D and H. The type of normal backlash tolerance is related to the accuracy grade. Different types of normal backlash tolerances and minimum normal backlash combinations are allowed. In general, the recommended correspondence between the normal backlash tolerance type and the minimum normal backlash type is shown in the figure. 8.6 The tooth thickness tolerance T is specified in Table 14.
9 Drawing marking
9.1 The gear working drawing L should be marked with the numerical (letter) code of the gear accuracy grade and the minimum normal backlash type and the normal backlash tolerance type.
Marking example
GB 11365—89
The three tolerance groups of gears have the same accuracy of 7, the minimum normal backlash type is b, and the normal backlash tolerance type is 8:7
GB11365
Minimum normal backlash and normal backlash tolerance type Accuracy grades of tolerance groups I, II, and III
The two tolerance groups of gears have the same accuracy of 7, the minimum normal backlash is 400μⅢ, and the normal backlash tolerance type is B:9.1.2
GB 11365
Normal backlash tolerance type
Minimum normal backlash value
Accuracy grades of tolerance groups I, II and III
9.1.3 The accuracy of tolerance group I of gears is grade 8, the accuracy of tolerance groups II and III is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance type
Minimum normal backlash type
Accuracy grade of tolerance group III
Accuracy grade of tolerance group II
Accuracy grade of tolerance group I
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade2 According to the working requirements and production scale of the gear pair, select one inspection group from the following tolerance groups to evaluate and accept the accuracy of the gear pair. The inspection group can be determined by the supply and demand parties of the order. Inspection group of the first tolerance group
AF (for 4 to 8 grade accuracy)
AF. (for 7 to 12 grade accuracy straight bevel gear pairs, for 9 to 12 grade slightly helical bevel gear pairs)
Inspection group of the second tolerance group
Af (for 4 to 8 grade accuracy)
GB11365-89
△. (For straight-cone gear pairs with accuracy levels 7 to 12, and for helical and curved bevel gear pairs with accuracy levels 9 to 12) 4/zkc (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap e greater than or equal to the limit value in Table 2) /△fzz (For gear pairs with accuracy levels 4 to 8 and longitudinal overlap es less than the limit value in Table 2). Inspection group of tolerance group III
Contact spots.
7.a For each accuracy level, the tolerance numbers of various inspection items of gear pairs are as follows: 7.3.1 Fic and fic are as specified in A2 and A2.1 in Appendix A. 7.3.2 fc is as specified in Table 5, Fizc is as specified in Table 8, and F is as specified in Table 9; fis is as specified in Table 10, and fzz is as specified in Table I1. 7.3.3 The provisions of contact spots are as specified in 6.2.3. 7.8.4 ±fAM, ±f, ±E are as specified in Tables 16, 17, and 18 respectively. 8 Gear pair backlash
8.1 The standard stipulates that there are 6 types of minimum normal backlash of gear pairs: a, b, c, d, e and h. The minimum normal backlash value is the maximum with a and zero with h (as shown in the figure below). The minimum normal backlash type is particularly related to the accuracy grade. h
8.2 After the minimum normal backlash type is determined, Es and ±E2 are obtained according to Table 13 and Table 18. 8.a The minimum normal backlash iam is specified in Table 12. When there are special requirements, 7amin may not be determined according to the values listed in Table 12. At this time, E and ±Es are calculated from Table 13 and Table 18 using linear interpolation. 8.4 The maximum normal backlash nm is specified as max = ([E1 +Es2/+T+T2+E^1+2)cos. E is the compensation part of the manufacturing error, which can be obtained from Table 15. 8.5 This standard specifies five types of normal backlash tolerances for gear pairs: A, B, C, D and H. The type of normal backlash tolerance is related to the accuracy grade. Different types of normal backlash tolerances and minimum normal backlash combinations are allowed. In general, the recommended correspondence between the normal backlash tolerance type and the minimum normal backlash type is shown in the figure. 8.6 The tooth thickness tolerance T is specified in Table 14.
9 Drawing marking
9.1 The gear working drawing L should be marked with the numerical (letter) code of the gear accuracy grade and the minimum normal backlash type and the normal backlash tolerance type.
Marking example
GB 11365—89
The three tolerance groups of gears have the same accuracy of 7, the minimum normal backlash type is b, and the normal backlash tolerance type is 8:7
GB11365
Minimum normal backlash and normal backlash tolerance type Accuracy grades of tolerance groups I, II, and III
The two tolerance groups of gears have the same accuracy of 7, the minimum normal backlash is 400μⅢ, and the normal backlash tolerance type is B:9.1.2
GB 11365
Normal backlash tolerance type
Minimum normal backlash value
Accuracy grades of tolerance groups I, II and III
9.1.3 The accuracy of tolerance group I of gears is grade 8, the accuracy of tolerance groups II and III is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance type
Minimum normal backlash type
Accuracy grade of tolerance group III
Accuracy grade of tolerance group II
Accuracy grade of tolerance group I
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade3 The accuracy of the first tolerance group of gears is grade 8, the accuracy of the second and third tolerance groups is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance type
Minimum normal backlash type
Accuracy grade of the third tolerance group
Accuracy grade of the second tolerance group
Accuracy grade of the first tolerance group
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade3 The accuracy of the first tolerance group of gears is grade 8, the accuracy of the second and third tolerance groups is grade 7, the minimum normal backlash type is c, and the normal backlash tolerance type is B:
GB 11365
Normal backlash tolerance type
Minimum normal backlash type
Accuracy grade of the third tolerance group
Accuracy grade of the second tolerance group
Accuracy grade of the first tolerance group
Table 3 Pitch cumulative tolerance Fp and K pitch cumulative tolerance Fp value L, m
L, mm
Note: F, and pk are based on the midpoint pitch circle Arc length L table: When looking up F, take
When looking up, take -
Midpoint detent circle diameter, mm
K yuan mn
GB11865—89
Continued Table 3
(When there is no special requirement, K value is Z/6 or the closest number of teeth) Table
Gear ring runout tolerance F, detection
Midpoint normal module
10 ~ 16
Accuracy grade
Midpoint scale diameter, mm
GB 11365—89
Continued Table 4
Midpoint normal module
2 1 ~ 3.5
>10 ~16
>16 ~25
>3.5 ~6.3
>10 ~16
>16 ~ 25
>25 ~ 40
>10 ~ 16
16 -25
>25~40
1 ~ 3. 5
Accuracy grade
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