Looking to produce gears with exceptional accuracy? Look no further than the gear hob! This versatile tool can handle various finishing processes and gear profiles, making it a go-to for manufacturers across industries.
But with so many types of hobs available, it can be tough to know which one to choose. That’s why we’ve put together this comprehensive guide to help you navigate the world of gear hobs. From involute spline hobs to sprocket hobs, we’ve got you covered.
So buckle up and get ready to learn everything you need to know about this essential manufacturing tool!
The gear hob is a tool used to produce spur and helical gears with exceptional accuracy. It can be utilized for various finishing processes such as pre-shaving and pre-grinding, and can accommodate different gear profiles, including those with convex corners, half-top teeth, and top cutting.
Hobs can be produced in two types: with a hole or a handle (rod type), and can have either a single head or multiple heads. The accuracy grades typically range from A to AAA.
Additionally, hobs can be classified based on whether they are used for dry cutting or with coolant during the cutting process.
In terms of specifications, the range of hob types includes holes and shanks, with a general range of modulus from 0.25 to 33. The diameter control DP range is from 0.75DP to 100 DP, and the maximum diameter and length of the hob are 330mm and 380mm, respectively.
Accuracy classes are determined based on DIN/GB standards and can range from A to AAA, with AAA being the highest accuracy class.
Involute spline hob
The commonly used involute spline standards include: DIN 5480, DIN 5482, ANSI B92.1, B92.2, BS3550, GOST-6033, GBT3478, and others.
Hobs for parallel side splines
The production of hobs adheres to a variety of standards, including: DIN 5461, DIN 5462, DIN 5463, DIN 5464, DIN 5465, DIN 5471, DIN 5472, DIN 9611, ISO 14, UNI 220, UNI 221, UNI 8953, and GB/T1144-2001, among others.
Rectangular spline (GB/T1144-1987)
The spline connection is multi tooth work, with high bearing capacity, good centricity and guidance, shallow tooth root, less stress concentration, and less strength weakening of shaft and hub.
Rectangular spline is easy to process and can obtain high precision by grinding.
Two series are specified in the standard: light series for static connection with light load, and medium series for medium cutting load.
The tooth profile of involute spline is involute, and there is radial force on the tooth when it is loaded, which can play the role of automatic centering, so that the force on each tooth is uniform, with high strength and long service life.
The processing technology is the same as that of gear, and it is easy to obtain high precision and interchangeability.
There are three kinds of standard pressure angleα0 of involute spline: 30 °, 37.5 ° and 45 °.
It is widely used. Such as aircraft, automobiles, tractors, machine tool manufacturing, agricultural machinery and general mechanical transmission devices.
Involute spline (GB/T3478.1-1995)
It is used for connection with large load, high centering accuracy and large size.
Hobs for use in the production of automotive and industrial roller chains are manufactured in accordance with a range of standards and non-standard forms.
General sprocket pitch range: 76.2 mm.
Standards: There are too many ANSI, ASA, IS, DIN, JIS-B GB sprocket standards, many of which are counterfeit.
Worm gear hob
The most crucial type of worm hob is the worm type, including ZI, ZN, ZK, and ZA.
Hobs can have either a single or multiple head and be produced with either a hole or handle type. The lead angle for these hobs typically ranges up to 45 degrees.
There are two methods for cutting with a hob: tangential feed and radial feed.
Hobs with special tooth profile
Hobs with specialized tooth shapes can be utilized for various parts as long as they are used for the generation and processing of external gears.
Straight tooth synchronous pulley hob
The production of synchronous pulley hobs is used for a variety of belts and pulleys with involute and HTD profiles.
Both top-cut and non-top-cut designs are available. The common models of pulleys include involute profiles like “T” and “S,” as well as HTD, MXL, XL, L, H, XH, and XXH.
Heavy double cutting hob
The production of specially designed double-cut hobs decreases cutting time by incorporating special cutting edges in grooves. These hobs are specifically designed for gears with modules 5.5 and above.
The use of specially designed double-cut hobs offers several benefits, including:
- Significant reduction in cycle time
- Easy implementation
- Decreased wear on the hob
These hobs can be used with both manual and CNC hobbing machines.
Dry cutting hob
The CNC gear hobbing machine uses this hob for high-speed cutting to increase productivity.
The cutting edge length of this hob is extensive, and it features a large number of grooves.
This enhances the hob’s processing lifespan with just one grinding.
It is ideal for use in large-scale automatic production lines.
For the best results, it is recommended to follow the hob’s specifications such as diameter, number of grooves and heads, and cutting parameters.
The objective is to minimize cutting time and maximize the hob’s lifespan.
- Decreased cycle time
- Increased number of parts sharpened per cycle
- Reduced inventory
- Fewer variables for seamless production
- Increased factory capacity without additional investment in land, machinery, or manpower
- Lowered cost per component.
- Both dry and wet cutting options
- Different types of holes and handles available
- Single and multi-thread options
- Capable of handling large parts such as those used in two-wheeled vehicles, automobiles, gear rings, chain wheels, etc.
- Simple to implement.