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From Manual of Gear Design: Spur and Internal Gears, Volume II

THE LOAD CARRYING ABILITY OF A PAIR OF GEARS MAY BE LIMITED BY EITHER THE BEAM STRENGTH OF THE GEAR TEETH, OR THE SURFACE ENDURANCE LIMIT OF THE MATERIAL. THE LOWER OF THESE TWO VALUES WILL BE USED TO ESTABLISH THE LOAD CARRYING ABILITY OF ANY PAIR, AND MUST BE GREATER THAN THE MAXIMUM DYNAMIC LOAD.

WHENEVER THERE IS AN ERROR IN ACTION BETWEEN A PAIR OF GEARS, ONE OF TWO REACTIONS MUST TAKE PLACE: THE CONNECTED MASSES MUST BE ACCELERATED AND DECELERATED TO COMPENSATE FOR THIS ERROR, OR THE SYSTEM MUST BE ELASTICALLY DEFORMED THE AMOUNT OF THE ERROR. IN PRACTICE A COMBINATION OF THE TWO WILL OCCUR. EVEN WITH PERFECT GEARS, THERE WILL BE AN ERROR IN ACTION DUE TO THE DEFORMATIONS UNDER LOAD. THE LOAD CAUSED BY THESE REACTIONS IS CALLED THE DYNAMIC LOAD.

THE DERIVATION OF THE DYNAMIC LOAD EQUATIONS IS GIVEN IN ANALYTICAL MECHANICS OF GEARS.

Terms and Symbols

 a = ACCELERATION, FT/SEC 2 A = LOAD DEFORMATION FACTOR A 1 = PRESSURE ANGLE FACTOR FOR ACCELERATION B = MASS FACTOR FOR MATERIAL, LB-SEC 2/IN 3-FT C 1 = LOAD @ R REQ'D TO DEFORM GEAR TEETH AMOUNT OF e 1 LBS C x = LOAD @ R REQ'D TO DEFORM SYSTEM TEETH AMOUNT OF e 1 LBS d = ELASTIC DEFORMATION OF SYSTEM UNDER APPLIED LOAN, INCHES d s = DIAMETER OF SHAFT, INCHES D = DIAMETER OF CYLINDER, INCHES e = ERROR IN ACTION, INCHES e' =

Products & Services
Spur Gears

Spur gears are the simplest type of gear. Transmitting power between parallel axes, the teeth project radially on the disc.

Worms and Worm Gears

Worms and worm gears are gear sets that offer high gear reduction and torque multiplication with a small footprint. A worm drive is a cylindrical gear with a shallow spiral thread that engages the worm gear in a non-intersecting, perpendicular axes configuration.

Gears

Gears are rotating mechanical devices employing 'teeth' in order to transmit torque between separate axes. Two or more cooperating gears are called a transmission and can produce a mechanical advantage by changing speed, torque or rotation direction.

Bevel and Miter Gears

Bevel gears are gears designed to transmit motion between intersecting axes. Perpendicular arrangements are most common, but bevel gears can be manufactured for nearly any angle. The teeth bearing surface of the gear, or surface pitch, is conically shaped or tapered. Miter gears are bevel gears manufactured in a 1:1 ratio, with the same number of teeth on mating gears and with perpendicular axes.

Metric Gears
Metric gears are defined by module, which designates the center-to-center distance between successive teeth. This criteria of gear selection is used in countries which have adopted the metric system and is intended to standardize gear selection.

Topics of Interest

Overview DESIGN OF GEAR DRIVES FOR EXTREME CONDITIONS: by Buckingham and Khiralla was presented to AGMA at the 41st annual meeting in June 1957. Reprinted with permission of AGMA. ACCELERATED...

Helical Gear Tooth Loads THE LOAD CARRYING ABILITY OF A PAIR OF GEARS MAY BE LIMITED BY EITHER THE BEAM STRENGTH OF THE GEAR TEETH, OR THE SURFACE ENDURANCE LIMIT OF THE MATERIAL. THE LOWER OF THESE...

Overview In principle, the design of internal gear teeth is the same as that for spur gears. Any of the basic rack forms used for spur gears may be applied to internal gears. The internal gear...

Gear tooth geometry is determined primarily by pitch, depth, and pressure angle. Standard pitches are usually whole numbers when measured as diametral pitch , the ratio of the number of teeth to the...

Overview Q3-1 With spur gears having twisted teeth (cycloidal), what is the form of the line of contact along the tooth surface? What is the form of pitch surface in spur gears, bevel...

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