Page 100 - Personal Study Notes (Engineering Metrology - 22342)

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Q. What are the errors in Gears?

Q. Explain Analytical and functional inspection Gear.

Inspection of gear is mainly of two types: (i) Analytical, and (ii) Functional.

Analytical Inspection:

- It is necessary to differentiate between the measurements of the individual parameters
of gear, i.e. their individual errors.

- To measure all the individual gear parameters and their errors, it is necessary to know
the errors of gear cutting machine, so that, the gear production can be controlled and
the machine eon be reset.

- The analytical inspection of gear involves in determination of following teeth elements,
in which, the errors are caused due to manufacturing errors.

(a) Tooth profile, (b) Spacing, (c) Pitch, (a) Run out (e) Thickness or tooth. (f) Lead, (g)
Backlash.

- But, this inspection method is not preferred in Industries, because it Is very slow,
Complex and tedious method.

- Also, the discrete error values of pitch, tooth profile etc. cannot give overall
assessment regarding the accuracy of gear. It is not easy to assess accurately, how
these elements, values combine in practice to give a prescribed performance under
operational conditions,

Functional Inspection:

- The overall accuracy of gear may be determined by checking the combined effect of
errors in the individual parameters. Therefore, it is preferred and widely used In
industries,

- It consists of carrying out the running test of a manufactured gear with master gear, to

Engineering Metrology (Only For Personal Use) 4