Total Lead Deviation
Distance between the highest and lowest points on the flank trace within the analysis region Lß measured perpendicular to a zero-error reference line. When working to ISO or DIN standards any high point outside of the analysis region is included.
Lead Slope Deviation
Positive or negative deviation of a best-fit reference line through the flank trace. Measured perpendicular to the start point of a zero-error reference line over the analysis region. When given the symbol fHß’ the value is from the reference lines over the full face width of the gear.
Lead Form Deviation
Distance between the highest and lowest reference lines that touch the flank trace and are parallel to the best-fit reference line. Measured perpendicular to a zero-error reference line. When working to ISO or DIN standards any high point outside of the analysis region is included.
Typically used to compensate for tooth deflection under load and influence load and transmission error TE of gear systems. Modifications can be the same or different on left and right flanks.
Typically used to compensate for system deflection and influance load distribution over the face width of the gear.
Constantly increasing relief of the flank line in an arc like progression. Typically central over the face width of the gear.
Lead End Relief
Contantly increasing relief of the flank line applied over a short distance at one or both ends of the face width of the gear. Can be linear, arc like or parabolic in shape.
Lead Slope Modification
Constantly increasing relief of the flank line applied over the full face width of the gear. It is not necessarily linear.
Tooth thickness is measured over physical teeth but our gear inspection machines are also able to measure tooth spaces on request.
Mdk = over two rollers MdR = over two balls
Distance over two balls or rollers of diameter Dm sat in a tooth gaps at, or as close to, 180 degrees as possible.
Circular tooth thickness in normal section at reference diameter d.
Base Tangent (Span)
Base tangent (span) over k number of teeth. Linear distance in normal section over k number of teeth which is tangent, or as close as possible, to the cylinder formed by base daimeter db. For an internal gear k is number of gaps.
Tip and Root Diameter
Measured da tip diameter and the df root diameter.
z = number of external teeth. eg. 20z = 20 external teeth.
-z = number of internal teeth. eg. -60z = 60 internal teeth.