Herringbone Gears

Herringbone Gears

A herringbone gear, a specific type of double helical gear, is a side-to-side (not face-to-face) combination of two helical gears of opposite hands. From the top, the helical grooves of this gear look like the letter V., Unlike helical gears. They do not produce an additional axial load.

A herringbone gear is a combination of double helical gears with two helices arranged on opposite sides of the hand. The teeth of the herringbone gears are arranged at an angle called the helix angle, with no gaps between the left and right helixes, appearing in the shape of the letter "V" These letters together form a pattern that resembles a fishbone structure. Since this structure has more than two teeth meshing with each other at the same time, the advantage is that the power transmission is smooth.

The angled teeth of the herringbone gears help generate axial force and heat that is proportional to the magnitude of the helical tangent. The angle between the helix and the axis of rotation is 45 degrees; however, larger helix angles provide higher speeds. The arrangement of the two teeth of the herringbone gear counteracts the thrust exerted on each other, giving the advantage of smooth operation even at higher speeds.

Due to its special structure, the herringbone gear is difficult to manufacture, and the arrangement of the teeth increases the manufacturing cost, so it is more expensive than other gears. Herringbone gears help provide smoother, quieter operation and provide high speeds.

Custom Herringbone Gear

• Both large modules and large diameters are available.
• High precision, up to 0.05mm
• Quality control and management of the whole production process, including ingot smelting, forging, heat treatment, machining, and a strictly final inspection before delivery.
• Excellent product quality and service, competitive price, and “in-time” delivery.

When it comes time to manufacture gears, the number of components needed (aka batch size) and the complexity of the gear (with a simple spur gear being very easy to make, and a herringbone being slightly harder to make on mass) determines the choice of tool and gear manufacturing method. These methods include casting, forging, extrusion, powder metallurgy, and blanking. Regardless of the chosen method, most procedures start with a gear blank before the machining process helps to achieve the final surface, shape, size, and surface finish of the gear.

Machining Herringbone Gears

An effective cutting process for a herringbone gear typically involves hobbing, milling, and shaping, though these methods depend largely on whether or not a gap is required between the two helixes or if the herringbone is to be continuous.

1) Hobbing

When cutting herringbone teeth, rotary cutters and hobs are typically used. However, their functionality is only effective when there is a gap large enough to allow for cutter runout between the right and left helixes. Hobbing machines can be manufactured today to machine herringbone teeth in gears up to 5.6m in diameter.

2) End Milling

Cutting teeth in herringbone gears is not solely regulated to hobbing machines; end mills also have the capability of machining teeth, unaffected by whether or not the gears possess centre slots. Herringbone gears with a large diameter are generally better suited to be cut by end milling.

3) Shaping

Finally, we come to shaping – another suitable method to cut teeth on herringbone gears, provided they are continuous and contain a centre slot. Many similarities exist between the shaper used for cutting a helical gear and a herringbone gear, however, in the case of the herringbone gear two cutters – one for each helix -are controlled at once by an operator.