"what is hering borne gear and where it is used"?

Answer 1

They conduct power and motion between non-intersecting, parallel axis that may or may not have center groove with each group making two opposite helices. The two helix angle come together in the center of the gear face to form a 'V'. in these gears the end thrust forces cancel themselves out. Its difficult to cut this type of gear but its made easier by machining a groove in the face at the point of the apex of the 'V' creating a break in the middle of the herringbone gear teeth. They do not have any separating groove between the mirrored halves.

Action is equal in force and friction on both gears and all bearings. Herringbone gear also allow for the use of larger diameter shaft for the same volumetric displacement and higher differential pressure capability.

The most common application is in power transmission. They utilize curved teeth for efficient, high capacity power transmission. This offers reduced pulsation due to which they are highly used for extrusion and polymerization. Herringbone gears are mostly used on heavy machinery.
IN PUMPS:
herringbone gears will reduce shaft loads and produce a very quiet running pump.
Herringbone gears are actually double helical gears with teeth angles reversed on opposite sides. This causes the thrust produced by one side to be counterbalanced by the thrust produced by the other side. The two sets of teeth are often separated at the center by a narrow gap for better alignment and to prevent oil from being trapped at the apex.

Herringbone gears are best suited for quiet, high-speed, low-thrust applications where heavy loads are applied. Large turbines and generators frequently use herringbone gears because of their durability.

Answer 2

Suresh Kumar's answer is correct and deserves the best answer. To add, herringbone gear is also called Double Helical Gear. I have seen herringbone gears of 1.2 m OD (Outer Diameter) when I visited a Cold-Rolling Mill Section within one of the Indian Ordnance Factories (I won't name it). There the flywheel of the motor shaft is 0.95 m in diameter. Two herringbone gears (both having same pitch and P.C.D.), one mounted on each roll, are used to drive the rolls at equal speed. The reduction in thickness of metal billet is 2 mm. This is specified by the distance between the centre of rolls, diameter of rolls and the thickness of the billet. The first one cannot be changed much except by very small value (order of micro-metre) as otherwise the gears would not mesh properly.

Another point is that slight misalignment may cause havoc so care should be taken when installing.

Answer 3

Herringbone refers to the visual pattern the gear teeth make on the gear face. It is a very strong and quiet running gear. These gears are used in drive-trains such as reduction gears for a turbine drive unit. I hope this helps.

Answer 4

I don't know if the spelling is correct, but there is a type of milk parlor (dairy farm) called a hering bone. Horse shoe shape. Also there is a hering bone implement for tractors, plowing or disc or spring tooth or something like that.

Answer 5

for sound and uded in ya ear