{"data":{"fields":"term_definition","term_definition":"<div class=\"definition\">The failure of a gear tooth by breakage as a result of repeated stress applications. It originates as a crack on the loaded side of the tooth usually in the fillet region and progresses until either a portion or the entire tooth fractures. Fatigue breakage is usually characterized by a series of contour lines and a focal point (or eye) in an area that is relatively smooth. The eye may occur at the surface or below the surface (subsurface). Other types of fatigue breakage are overload breakage - resulting from a sudden shock overload. Such failures do not show the progressive failure outlined above; and breakage due to excessive wear - this is actually a secondary failure since it is caused by excessive pitting or excessive surface wear which has reduced the tooth resistance to the breaking point.<\/div>"}}