Walk into a rolling mill, a sugar mill or a big pump house. The gears on the main shafts are usually double helical. Parkash Gears has made them since 1952, and this guide from a double helical gear manufacturer in Ludhiana tells you why heavy industry picks them, how they are made, what they cost and what to send us for a replacement that fits first time. Purana herringbone gear ghis gaya hai? Sample bhejein, centre gap bhi same rakhte hain.
In short: we make double helical gears up to 8 ft (2400 mm), from your drawing or your old gear, and cut teeth on your own forged blank. Small gears ship in 1 to 2 days.
What a double helical gear is (double helical garari kya hoti hai)
A helical gear has teeth cut at an angle. The teeth meet bit by bit, so the gear runs quieter and takes more load than a spur gear. A double helical gear has two sets of helical teeth on one body. One set is left hand, the other is right hand, and they meet in the middle. From the side the teeth look like a row of V shapes, which is why it is also called a herringbone gear. Hindi mein log isko V-teeth wali garari bhi kehte hain.
The problem it solves: axial thrust
An angled tooth does not only push its mating gear around. It also pushes it sideways along the shaft. That side force is called axial thrust. It grows with helix angle and torque. In a high torque drive, the thrust bearings and the housing that hold it become big, costly and hot.
In a double helical gear each half pushes the other way. The two forces meet in the middle and cancel. The bearings see almost no side load, only radial load. Simple shabdon mein: dono taraf ka dhakka ek dusre ko cancel kar deta hai. So the gear can use a steep helix angle for the smoothest, strongest mesh.
Where these gears are used
- Rolling mills in steel plants, on main drive and pinion stands
- Sugar mills, on cane crusher and mill roller drives
- Cement plants, on kiln and mill drives
- Large pumps, blowers and compressors
- Heavy mixers and extruders
- Marine and power plant gearboxes
The common thread is high torque, round the clock duty and downtime that costs lakhs per day.
Herringbone or centre gap: which one do you need
A true herringbone has no groove between the two halves. It needs special cutting machines. A gear with a centre gap has a narrow groove in the middle, which gives the cutting tool room to exit. Most industrial gears use this type, and this is what we normally make. For a replacement we match the centre gap width to the old gear, so it fits the same housing and shafts with no change.
How the gear is made
The blank is forged or rolled alloy steel (EN19, EN24 or EN353 as per duty), with a mill test certificate on request. The rough machined blank is stress relieved so it does not move after tooth cutting. Outside diameter, bore, faces and centre gap are turned to drawing on our VTL. Each helix is then cut on its own, with the machine set to the opposite hand for the second half. The two halves must match in lead and tooth spacing; if not, one half carries more load than the other. After through hardening or case hardening, tooth spacing, lead and runout are checked on both halves, and the match between the two helices is confirmed before dispatch.
We turn and cut gears up to about 8 ft (2400 mm) diameter. That covers most sugar, steel, cement and heavy engineering jobs. See everything we make, including single helix helical gears for lighter drives.
Job work (labour job) on your forged blank
Bahut se customers apna forged blank khud dete hain. We cut the double helical teeth, do the heat treatment and finish the gear on that blank. Labour job ka rate material ke bina hota hai, isliye cost kam rehti hai. Details on our gear job work page.
What decides the price
The price depends on outside diameter, face width, module, material and quantity. A 300 mm gear for a pump and a 2000 mm forged gear for a sugar mill are very different jobs, so we quote per drawing or per sample, not a flat rate. Drawing ya sample bhejein, same day quote milega. We make one piece or a batch.
How to order a replacement
Send us the old gear if you can, even a damaged one. If not, send the outside diameter and total face width, the centre gap width if there is one, the number of teeth and module, the helix angle and hand of each half, the bore, keyway or spline details, and photos of the gear in place that show clearance and mounting. Full details are on our double helical gears page.
FAQ
Kya aap sample se double helical garari bana sakte ho?
Haan. Purana gear bhejein, hum measure karke exact replacement banate hain. Centre gap bhi same rakhte hain.
Herringbone aur double helical mein kya fark hai?
Herringbone mein beech mein gap nahi hota. Double helical mein chhota centre gap hota hai jo cutting ke liye zaroori hai. Industrial use mein mostly centre gap wala hi chalta hai.
Job work karte ho?
Haan, customer ke forged blank par teeth cutting, heat treatment aur finishing.
Delivery time kitna hai?
Chhote gears 1 to 2 days. Bade forged gears par baat karke batate hain.
Which cities do you supply?
Punjab, Chandigarh, Haryana, Himachal and Delhi NCR by road, the rest of India by transport, and export orders in wooden box packing.
Talk to us
Parkash Gears, manufacturing gears since 1952, MSME (Udyam) registered. Spur, helical, double helical, bevel, worm and ring gears, sprockets and gearboxes, as per drawing or sample.
Contact: Ashok Goyal
Call or WhatsApp: +91 9915280866, +91 8146400866
Email: parkashgears@gmail.com
Address: 528, Oswal Street, Miller Ganj, Ludhiana, Punjab 141003
