GearHeads Corner

Have a had a lot of gearboxes apart in my life and to date have never seen a Herringbone gear in anything but a picture. What are the down sides to them compared to a helical gear and why do you think they are not more popular?

Herringbones, like helicals, are very quiet. They also have a self centering ability that
negates the use of a thrust bearing or plate to hold them in position. I dont think Ive
ever seen them used in a bevel, but the same effect is actually created by using a zerol
type of bevel, since the zero curvature is equal and opposite on each side of the face it
is very similar to a herringbone in its centering abilities..

Art

When I worked in shipbuilding and repair I got to work on an aircraft carriers herribone  reduction gear. The bull gear was huge and how they machined it so perfectly was amazing. I also got to inspect a tug boats reduction that was pitting and that one was awesome also. In addition to the attributes that art mentioned they are used mainly were the power transmission levels are very high. In the case of the air craft carrier the shaft horse power was something like 110,000 per shaft and they had 4. The hrribone pattern effectively gives more surface area per tooth than a spur type gear but are much harder to make.

Ken_Shea wrote: Have a had a lot of gearboxes apart in my life and to date have never seen a Herringbone gear in anything but a picture. What are the down sides to them compared to a helical gear and why do you think they are not more popular?

As an aside they were invented by Andr? Citro?n and used in the rear axle of his early automobiles.
that's why the Citroen badge is the two inverted Vees to show the tooth shape.

I did NOT know that. :)

Art