Gear Unit Vibration Evidence Worksheet and GMF Reference
Organize applicability, acceptance context, measurement and source evidence for qualified review against ISO 20816-9:2020. The separate fixed-axis gear-mesh-frequency calculator is a general engineering reference; it does not calculate an ISO vibration grade, gear condition diagnosis, alarm, trip or operating instruction.
Evaluation-evidence record
Fixed-axis gear mesh frequency reference
This separate calculator uses a general engineering kinematic relation documented by SKF. It is not an ISO 20816-9 classification formula. It applies to a conventional fixed-axis gear when the entered rotational speed belongs to the shaft carrying the entered tooth count. It does not model planetary/epicyclic relative motion and does not diagnose damage.
Z = positive integer number of teeth; n = shaft speed in r/min. Source example: 50 teeth at 1 180 r/min gives 59 000 cycles/min, or 983.3 Hz.
What was corrected
Standard and source register
| Şəxsiyyət nömrəsi | Source and lifecycle | Verified support | Not supported |
|---|---|---|---|
| S1 | ISO 20816-9:2020 Edition 1 – published June 2020 – confirmed 13 July 2026 – stage 90.93 | Gear-unit boundary, ratings, acceptance/agreement context, design and steady-state conditions, exclusions, measurement targets/directions and diagnostic limitation. | Former numerical tables, three speed categories, planetary multiplier, bevel equivalence, exact grade semantics, boundary rules, alarms, trips or operating actions. |
| S2 | ISO 8579-2:1993 Edition 1 – withdrawn 3 March 2016 – revised by ISO 20816-9:2020 | Direct predecessor lifecycle and former manufacturer-facility acceptance scope. | No proof that a former value, grade, procedure or note is unchanged in the current document. |
| S3 | SKF Spectrum analysis 2012 SKF Group – Gear Mesh Frequency section | For a fixed-axis gear, tooth count multiplied by its shaft speed; 50 teeth at 1 180 r/min = 59 000 cycles/min = 983.3 Hz. | Not an ISO 20816-9 grade, planetary model, acceptability rule or standalone diagnostic conclusion. |
Review notes
Why does this page no longer output Grade or Zone A, B, C or D?
The former values lacked a checked licensed ISO 20816-9:2020 clause/table, exact grade/group, complete measurement definition and verified boundary convention. A numerical classification would therefore be unsupported.
Can any field measurement be treated as an ISO acceptance test?
No. The public record centers manufacturer-facility acceptance within design ranges. On-site acceptance or routine measurements require agreement between the applicable parties.
Can ISO 20816-9 diagnose gear tooth condition?
The official abstract says its criteria have limited application to gear condition and that specialist gear-condition techniques are outside scope.
Does the GMF calculator handle planetary gearboxes?
No. The simple SKF relation here is limited to a fixed-axis gear using the tooth count and rotational speed of the same shaft. Planetary relative motion requires a different model.
Can this page recommend continued operation, monitoring frequency, maintenance, load reduction or shutdown?
No. The worksheet checks documentation completeness, and the GMF calculator returns only a kinematic frequency. Neither supplies an acceptance or operating decision.
Source access: 17 July 2026. No closed ISO clause, table, coefficient or grade boundary is copied or inferred. The former numerical classifications, speed categories, planetary multiplier, bevel equivalence, persistence and operating advice were removed because their current normative basis and complete application conditions were not verified.
