RUSH GEARS inc. BEVEL and MITER GEARS are used as right angle drives where high efficiency is required. They transmit motion and power between right angle (90°) intersecting shafts at speed ratios from 1:1 (Miters) and 1.5:1 to 6:1 (Bevels).
Bevel and Miter Gears are usually cut 20° pressure angle with the long and short addendum system being used to compensate for tooth undercut in gears and pinions having low numbers of teeth.
Only Miter Gears of the same number of teeth, pitch and pressure angle, will operate together. However, more than two like miters may be used in a set such as a differential arrangement.
Bevel Gears and Pinions are listed in pairs and are not interchangeable with gears of a different pitch, pressure angle or ratio. It is advisable when replacing a worn gear to replace the complete set, particularly in low ratio sets.
CONIFLEX TOOTH FORM: In addition to using the long and short addendum system, most all RUSH GEARS inc. miter gears and bevel gear sizes are generated cut with the Coniflex tooth form. This form has a localized tooth bearing running lengthwise along the gear tooth and because of the localization of tooth contact permits some realignment of gears at assembly and during operation without heavy loading at the toe or heel of the tooth.
MOUNTING: When mounting bevel and miter gears it is important that shafts be exactly 90° apart to eliminate mis-alignment of bevel or miter. The Coniflex tooth form will permit a slight adjustment in assembly, but should not be used to overcome severely mis-aligned shafts. Gears should be mounted at the correct distance from the cone or apex center with thrust bearings used in back of the hubs to absorb the backward thrust created in this type of gearing.
The MOUNTING DISTANCE ("MD") dimension shown for each Miter or Bevel Gear is the distance from the back end of the gear hub of one gear to the centerline of its mating gear. When properly mounted to this dimension, the ends of the teeth of these gears will be flush with each other. If the mounting distance is too long the gears will not be fully in mesh, thus permitting the load to be concentrated above the pitch line and allowing excessive backlash. When distance is too short, gears may bind causing excessive heat, wear and breakage.
LUBRICATION: Adequate lubrication is a necessary factor in this type of gearing to insure longer life of gears and bearings. Residual type (straight mineral) oils are recommended for exposed gearing, hand or bath lubricated. Intermediate Viscosity oils for enclosed gearing subject to moderate temperatures should prove satisfactory in normal operation. Heavy duty application, where pressures or shock loads are moderate to high require Mild Extreme Pressure (EP) lubricants. Specific recommendations can be made by engineers of the many oilcompanies in this field.