_____ is defined as the amount by which a tooth space exceeds the thickness of an engaging tooth
Journal bearings are conformal contacts that experience much lower pressures than that experienced by gear teeth and REB's, which are non-conformal contacts Suppose an engineer needs to design a journal bearing to support a shaft of given diameter that is to be loaded with a prescribed load and rotated at a prescribed rate. most often occurs in gears with small numbers of teeth and low pressure angles. Circular Tooth Thickness is the distance from a point on one side of a gear tooth to a corresponding point on the opposite side of the same tooth, measured along the pitch circle. Backlash is the amount by which the width of a tooth space exceeds the thickness of the engaging gear tooth. Backlash is achieved either by decreasing tooth thickness slightly (increasing tooth space) on one or both the amount by which the dedendum in a given gear exceeds the addendum of its mating gear the amount by which the width of a tooth space exceeds the thickness of the engaging tooth measured on the pitch circles pressure angle the angle that the line of action makes with the line perpendicular to the line of centers the quantity to which the predicted film thickness is compared in assessing a bearing design length over diameter dimensionless ratio that, along with S, sets the operating point (hmin/C) for a journal bearing Addendum is the height of the tooth above the pitch circle. Dedendum is the depth of the tooth below the pitch circle. Whole Depth is the total length of a tooth space equal to the sum of the addendum and dedendum. Clearance is the distance between the outside diameter of a gear and the root diameter of its mate. Basic Gear. Terminology. INVOLUTE. Face Width is the length of the teeth in the axial direction. Outside Diameter (O.D.) is the diameter of a circle around the outer surface, or tops of the gear teeth. Pitch Diameter (P.D.) is the diameter of the pitch circle. Pitch Circle. tooth on the pitch circle, unless otherwise specified. CLEARANCE-OPERATING (c) is the amount by which the dedendum in a given gear exceeds the addendum of its mating gear. CONTACT RATIO (m c) in general, the number of angular pitches through which a tooth surface rotates from the beginning to the end of contact. DEDENDUM (b) is the depth of a tooth space below the pitch line. It is normally greater than the addendum of the mating gear to provide clearance. DIAMETRAL PITCH (P) is the ratio of the number of teeth to the pitch diameter. FACE WIDTH (F) is the length of the teeth in an axial plane. She would choose the radial clearance (c), bearing length (L) and lubricant, the other relevant parameters, journal radius, load, rotation rate, presumed to be given. Based on the viscosity temperature behavior she would iterate to find operating temperature and viscosity. BACKLASH (B) is the amount by which the width of a tooth space exceeds the thickness of the engaging tooth on the pitch circles. As actually indicated by measuring devices, backlash may be determined variously in the transverse, normal, or axial-planes, and either in the direction of the pitch circles or on the line of action.
Backlash is the amount by which the width of a tooth space exceeds the thickness of the engaging tooth on the pitch circles.