Herringbone Gear


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herringbone gear

[′her·iŋ‚bōn ‚gir]
(mechanical engineering)
The equivalent of two helical gears of opposite hand placed side by side.

Herringbone Gear

 

a spur gear with V-shaped helical teeth. The mutual inclination of the tooth segments on opposite sides compensates the axial thrust produced by single helical gears. Herringbone gears afford smooth operation and increased load-carrying capacity, which are characteristic of helical gear transmissions in general. They are used in medium-size and large transmissions, including special transmissions operating at pitch-circle velocities up to 200 m/sec (turbine reduction gears).

Figure 1. Herringbone gears: (a) continuous-tooth type, (b) double helical gears, (c) two pairs of gears

Continuous-tooth herringbone gears (Figure 1,a) require special equipment to machine the teeth. Double helical, or conventional herringbone, gears (Figure l,b) have a gap, or groove, where the two sets of teeth meet; they may be made on ordinary gear-hobbing machines, but the width of the gear wheel must be increased by the width of the groove g. Transmission through two pairs of helical gears with opposed teeth (Figure 1,c) enables the space between the gears to be used for another transmission.

References in periodicals archive ?
The double helical gears are further segmented into two categories with gap between the helices and without gap between the helices (Herringbone gears).
LEWCO's components include a pressurized lubrication system that force-feeds lubricant to all power-end bearings including upper and lower crosshead slides; AGMA "Class 10" double-helix pinion and main gear sets providing twice the capacity of conventional herringbone gears; a balanced crankshaft that reduces noise and vibration and helps extend component life throughout the pump; and a double-wall, welded-steel frame, mounted on a heavy-duty oilfield skid.