GB/T 10227-2025 Accuracy of fine-pitch cylindrical worm and worm-wheel English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 21.200 CCS J 17
GB/T 10227-2025 replaces GB/T 10227-1988
Accuracy of Fine-Pitch Cylindrical Worm and Worm-Wheel
Issued on 2025-08-29 Implemented on 2026-03-01
Issued by State Administration for Market Regulation Standardization Administration of China
Contents
Foreword
1 Scope
2 Normative references
3 Terms and definitions
3.1 Worm deviations
3.2 Worm-wheel deviations
3.3 Composite deviations
4 Accuracy system
4.1 General provisions
4.2 Accuracy grades
5 Tolerances
5.1 General provisions
5.2 Ratio between grades
5.3 Rounding rules
5.4 Calculation of tolerances
6 Inspection rules
6.1 Lead deviation
6.2 Profile deviation
6.3 Pitch deviation
6.4 Radial run-out
6.5 Pin measurement distance deviation
6.6 Tangential composite deviation
6.7 Radial composite deviation
7 Drawing indications
Appendix A (Informative) Recommended backlash values for fine-pitch cylindrical worm and worm-wheel assemblies (or worm and helical gear assemblies)
References
Accuracy of Fine-Pitch Cylindrical Worm and Worm-Wheel
1 Scope
This document specifies the accuracy system, tolerances, inspection rules, and drawing indication requirements for fine-pitch cylindrical worms, worm-wheels (or helical gears), and worm drive assemblies.
This document applies to cylindrical worm and worm-wheel assemblies with an axis intersection angle Σ of 90°, where the module m ranges from 0.1 mm to 0.5 mm, the worm reference diameter d₁ ≤ 30 mm, and the worm-wheel reference diameter d₂ ≤ 320 mm. The worm types include Archimedes worm (ZA), involute worm (ZI), straight-sided normal worm (ZN), and cone-enveloping worm (ZK).
This document also applies to worm and helical gear assemblies consisting of an involute worm (ZI) and an involute helical gear.
Note: In this document, "fine-pitch cylindrical worm" and "fine-pitch cylindrical worm-wheel" are respectively abbreviated as "worm" and "worm-wheel"; the involute helical gear is abbreviated as "helical gear"; "fine-pitch cylindrical worm and worm-wheel drive assembly" is abbreviated as "worm and worm-wheel assembly"; "fine-pitch involute cylindrical worm and involute helical gear drive assembly" is abbreviated as "worm and helical gear assembly"; both "worm and worm-wheel assembly" and "worm and helical gear assembly" are collectively referred to as "worm drive assembly".
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the editions cited apply. For undated references, the latest edition (including any amendments) applies.
GB/T 2363 Accuracy of fine-pitch involute cylindrical gears
GB/T 2821 Gear geometrical data code designation
GB/T 3374.1 Gears—Terminology and definitions—Part 1: Geometric definitions
GB/T 3374.2 Gears—Terminology and definitions—Part 2: Geometric definitions for worm-wheels
3 Terms and definitions
The terms and definitions defined in GB/T 2821, GB/T 3374.1, and GB/T 3374.2, and the following terms and definitions apply to this document.
3.1 Worm deviations
3.1.1 worm lead deviation Fpₓ₁
The difference between the actual dimension and the nominal dimension of the worm lead.
3.1.2 worm axial single pitch deviation fpx₁
In the axial plane of the worm, the difference between the actual pitch and the nominal pitch at any tooth.
Note: See Figure 1.
Legend:
l₁ — Actual pitch;
l₂ — Nominal pitch;
fpx₁ — Worm axial pitch deviation.
Figure 1 Worm Axial Single Pitch Deviation
3.1.3 worm adjacent axial pitch deviation fux₁
In the axial plane of the worm, the difference between any two adjacent pitches.
[Source: GB/T 10089—2018, 3.1.5, modified]
**3.1.4 worm total axial profile deviation Fα₁
In the evaluated range of the worm axial plane, the axial distance between the two nearest design profile curves that enclose the actual profile curve.
Note: See Figure 2.
Legend:
1 — Design profile trace;
2 — Actual profile;
3 — Working portion of the profile;
Fα₁ — Worm total axial profile deviation.
Figure 2 Worm Profile Deviation
3.1.5 worm radial run-out Fr₁
In the axial plane of the worm, with a spherical probe contacting both flanks of the tooth in the middle of the tooth space for each tooth groove, the radial distance from the center of the probe to the worm axis, the difference between the maximum value and the minimum value of the radial measurement radius (r₁ᵢ) within the same axial section is the worm radial run-out (Fr₁).
See Figure 3.
Legend:
r₁ᵢ — Radial measurement radius of the spherical probe.
Figure 3 Worm Radial Run-Out
3.1.6 worm pin measured distance deviation fM
The difference between the actual outermost distance between the two measurement pins (one on each side) in the worm axial section and the nominal distance.
Note: See Figure 4.
Legend:
1 — Nominal pin measurement distance;
2 — Actual pin measurement distance;
fM — Pin measurement distance deviation.
Figure 4 Worm Pin Measured Distance Deviation
3.2 Worm-wheel deviations
3.2.1 worm-wheel profile deviation Fα₂
Within the working portion of the tooth profile on the worm-wheel mid-plane, the normal distance between the two nearest design profile traces that enclose the actual profile.
Note: See Figure 5.
Legend:
1 — Working portion of the tooth profile;
2 — Design profile trace;
Fα₂ — Worm-wheel profile deviation.
Figure 5 Worm-Wheel Profile Deviation
3.2.2 worm-wheel single pitch deviation fp₂
On the worm-wheel mid-plane, the difference between the actual pitch and the nominal pitch at the reference circle.
Note: See Figure 6.
Legend:
1 — Nominal pitch of the worm-wheel (arc length);
2 — Actual pitch of the worm-wheel (arc length);
fp₂ — Worm-wheel single pitch deviation.
Figure 6 Worm-Wheel Pitch Deviation
3.2.3 worm-wheel total cumulative pitch deviation Fp₂
On the reference circle of the worm-wheel, the maximum absolute value of the differences between the actual arc length and the nominal arc length between any two points on the same side of the teeth.
[Source: GB/T 10089—2018, 3.2.2, modified]
3.2.4 worm-wheel radial run-out Fr₂
In any single revolution of the worm-wheel, with a probe contacting both flanks in the tooth space at mid-tooth height, the maximum radial variation of the probe relative to the axis of the worm-wheel.
Note: See Figure 7.*
Figure 7 Worm-Wheel Radial Run-Out
3.3 Composite deviations
3.3.1 master worm
The worm paired with the worm-wheel under test in composite deviation measurements.
Note: The accuracy grade of the master worm is generally 2 or more grades higher than that of the worm-wheel under test.
3.3.2 master worm-wheel
The worm-wheel paired with the worm under test in composite deviation measurements.
Note: The accuracy grade of the master worm-wheel (which is often a helical gear) is generally 2 or more grades higher than that of the worm under test.
3.3.3 tooth-to-tooth tangential composite deviation fᵢₛ
The total amplitude value of the difference between the actual rotation angle and the theoretical rotation angle within one pitch of the worm-wheel (or worm) under test during single-flank meshing with the master worm (or master worm-wheel).
3.3.4 total tangential composite deviation Fᵢₛ
The total range of variation in the difference between the actual rotation angle and the theoretical rotation angle over one revolution of the worm-wheel (worm) under test during single-flank meshing with the master worm (master worm-wheel).
Note: See Figure 8.
Standard
GB/T 10227-2025 Accuracy of fine-pitch cylindrical worm and worm-wheel (English Version)
Standard No.
GB/T 10227-2025
Status
valid
Language
English
File Format
PDF
Word Count
11000 words
Price(USD)
330.0
Implemented on
2026-3-1
Delivery
via email in 1~5 business day
Detail of GB/T 10227-2025
Standard No.
GB/T 10227-2025
English Name
Accuracy of fine-pitch cylindrical worm and worm-wheel
GB/T 10227-2025 Accuracy of fine-pitch cylindrical worm and worm-wheel English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 21.200 CCS J 17
GB/T 10227-2025 replaces GB/T 10227-1988
Accuracy of Fine-Pitch Cylindrical Worm and Worm-Wheel
Issued on 2025-08-29 Implemented on 2026-03-01
Issued by State Administration for Market Regulation Standardization Administration of China
Contents
Foreword
1 Scope
2 Normative references
3 Terms and definitions
3.1 Worm deviations
3.2 Worm-wheel deviations
3.3 Composite deviations
4 Accuracy system
4.1 General provisions
4.2 Accuracy grades
5 Tolerances
5.1 General provisions
5.2 Ratio between grades
5.3 Rounding rules
5.4 Calculation of tolerances
6 Inspection rules
6.1 Lead deviation
6.2 Profile deviation
6.3 Pitch deviation
6.4 Radial run-out
6.5 Pin measurement distance deviation
6.6 Tangential composite deviation
6.7 Radial composite deviation
7 Drawing indications
Appendix A (Informative) Recommended backlash values for fine-pitch cylindrical worm and worm-wheel assemblies (or worm and helical gear assemblies)
References
Accuracy of Fine-Pitch Cylindrical Worm and Worm-Wheel
1 Scope
This document specifies the accuracy system, tolerances, inspection rules, and drawing indication requirements for fine-pitch cylindrical worms, worm-wheels (or helical gears), and worm drive assemblies.
This document applies to cylindrical worm and worm-wheel assemblies with an axis intersection angle Σ of 90°, where the module m ranges from 0.1 mm to 0.5 mm, the worm reference diameter d₁ ≤ 30 mm, and the worm-wheel reference diameter d₂ ≤ 320 mm. The worm types include Archimedes worm (ZA), involute worm (ZI), straight-sided normal worm (ZN), and cone-enveloping worm (ZK).
This document also applies to worm and helical gear assemblies consisting of an involute worm (ZI) and an involute helical gear.
Note: In this document, "fine-pitch cylindrical worm" and "fine-pitch cylindrical worm-wheel" are respectively abbreviated as "worm" and "worm-wheel"; the involute helical gear is abbreviated as "helical gear"; "fine-pitch cylindrical worm and worm-wheel drive assembly" is abbreviated as "worm and worm-wheel assembly"; "fine-pitch involute cylindrical worm and involute helical gear drive assembly" is abbreviated as "worm and helical gear assembly"; both "worm and worm-wheel assembly" and "worm and helical gear assembly" are collectively referred to as "worm drive assembly".
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the editions cited apply. For undated references, the latest edition (including any amendments) applies.
GB/T 2363 Accuracy of fine-pitch involute cylindrical gears
GB/T 2821 Gear geometrical data code designation
GB/T 3374.1 Gears—Terminology and definitions—Part 1: Geometric definitions
GB/T 3374.2 Gears—Terminology and definitions—Part 2: Geometric definitions for worm-wheels
3 Terms and definitions
The terms and definitions defined in GB/T 2821, GB/T 3374.1, and GB/T 3374.2, and the following terms and definitions apply to this document.
3.1 Worm deviations
3.1.1 worm lead deviation Fpₓ₁
The difference between the actual dimension and the nominal dimension of the worm lead.
3.1.2 worm axial single pitch deviation fpx₁
In the axial plane of the worm, the difference between the actual pitch and the nominal pitch at any tooth.
Note: See Figure 1.
Legend:
l₁ — Actual pitch;
l₂ — Nominal pitch;
fpx₁ — Worm axial pitch deviation.
Figure 1 Worm Axial Single Pitch Deviation
3.1.3 worm adjacent axial pitch deviation fux₁
In the axial plane of the worm, the difference between any two adjacent pitches.
[Source: GB/T 10089—2018, 3.1.5, modified]
**3.1.4 worm total axial profile deviation Fα₁
In the evaluated range of the worm axial plane, the axial distance between the two nearest design profile curves that enclose the actual profile curve.
Note: See Figure 2.
Legend:
1 — Design profile trace;
2 — Actual profile;
3 — Working portion of the profile;
Fα₁ — Worm total axial profile deviation.
Figure 2 Worm Profile Deviation
3.1.5 worm radial run-out Fr₁
In the axial plane of the worm, with a spherical probe contacting both flanks of the tooth in the middle of the tooth space for each tooth groove, the radial distance from the center of the probe to the worm axis, the difference between the maximum value and the minimum value of the radial measurement radius (r₁ᵢ) within the same axial section is the worm radial run-out (Fr₁).
See Figure 3.
Legend:
r₁ᵢ — Radial measurement radius of the spherical probe.
Figure 3 Worm Radial Run-Out
3.1.6 worm pin measured distance deviation fM
The difference between the actual outermost distance between the two measurement pins (one on each side) in the worm axial section and the nominal distance.
Note: See Figure 4.
Legend:
1 — Nominal pin measurement distance;
2 — Actual pin measurement distance;
fM — Pin measurement distance deviation.
Figure 4 Worm Pin Measured Distance Deviation
3.2 Worm-wheel deviations
3.2.1 worm-wheel profile deviation Fα₂
Within the working portion of the tooth profile on the worm-wheel mid-plane, the normal distance between the two nearest design profile traces that enclose the actual profile.
Note: See Figure 5.
Legend:
1 — Working portion of the tooth profile;
2 — Design profile trace;
Fα₂ — Worm-wheel profile deviation.
Figure 5 Worm-Wheel Profile Deviation
3.2.2 worm-wheel single pitch deviation fp₂
On the worm-wheel mid-plane, the difference between the actual pitch and the nominal pitch at the reference circle.
Note: See Figure 6.
Legend:
1 — Nominal pitch of the worm-wheel (arc length);
2 — Actual pitch of the worm-wheel (arc length);
fp₂ — Worm-wheel single pitch deviation.
Figure 6 Worm-Wheel Pitch Deviation
3.2.3 worm-wheel total cumulative pitch deviation Fp₂
On the reference circle of the worm-wheel, the maximum absolute value of the differences between the actual arc length and the nominal arc length between any two points on the same side of the teeth.
[Source: GB/T 10089—2018, 3.2.2, modified]
3.2.4 worm-wheel radial run-out Fr₂
In any single revolution of the worm-wheel, with a probe contacting both flanks in the tooth space at mid-tooth height, the maximum radial variation of the probe relative to the axis of the worm-wheel.
Note: See Figure 7.*
Figure 7 Worm-Wheel Radial Run-Out
3.3 Composite deviations
3.3.1 master worm
The worm paired with the worm-wheel under test in composite deviation measurements.
Note: The accuracy grade of the master worm is generally 2 or more grades higher than that of the worm-wheel under test.
3.3.2 master worm-wheel
The worm-wheel paired with the worm under test in composite deviation measurements.
Note: The accuracy grade of the master worm-wheel (which is often a helical gear) is generally 2 or more grades higher than that of the worm under test.
3.3.3 tooth-to-tooth tangential composite deviation fᵢₛ
The total amplitude value of the difference between the actual rotation angle and the theoretical rotation angle within one pitch of the worm-wheel (or worm) under test during single-flank meshing with the master worm (or master worm-wheel).
3.3.4 total tangential composite deviation Fᵢₛ
The total range of variation in the difference between the actual rotation angle and the theoretical rotation angle over one revolution of the worm-wheel (worm) under test during single-flank meshing with the master worm (master worm-wheel).
Note: See Figure 8.
