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Interpretation of Gear Errors

Update:08 Jan 2018

1. Tooth shape error: (fp) The sum of the positive side […]

1. Tooth shape error: (fp)
The sum of the positive side error and the negative side error within the scope of the tooth profile measured in the vertical direction based on the actual involute of the intersection of the actual profile and the pitch circle (for the right-angled profile of the shaft ) (Including pressure angle error and concavity and convexity error)
2. Teeth direction error: (fq)
The difference between the actual gear tooth curve and the theoretical curve. This direction error affects the contact condition of the tooth flank, and this error may cause concentrated contact between both ends of the gear, resulting in poor local contact. To avoid such poor contact, the tooth flanks are usually drum-shaped or crowning (relieving).
3. Single pitch error (ft)
The difference between the measured pitch and the pitch theoretical value on the pitch circle of any adjacent ipsilateral gear surface.
4. Adjacent pitch error (ftu)
A gear, the difference between the two measured pitch adjacent to each other on the pitch circle.
5. Accumulated pitch error (Ft)
The error between the sum of the measured pitch of any two isolated teeth on a pitch circle and the correct value on a pitch circle.
6. Normal Pitch Error (fte)
The error between the measured value and the theoretical value of the front normal pitch of gear.
7. Trench Deviation (PITCH LINE RUNOUT) (fr)
Use the ball or the measuring rod which can contact with the tooth surface near the node, and place it in each tooth groove one by one. In this way, the maximum eccentricity measured in the radial direction can be obtained.
Note: This will have an adverse effect on the gear noise, but also greatly affected by the gear processing, and grinding work axis accuracy, in order to improve the eccentricity accuracy, in addition to the use of sophisticated processing machine, in particular, to use high-precision Work axis. (Center hole)