9 Types of Hobs: How Much Do You Know?

Gear hob

Gear hob, used to generate spur and helical gears with the highest accuracy, including finishing, pre shaving and pre grinding of various profiles, such as with or without convex corners, half top teeth and top cutting.

Hobs are produced with hole or handle type (rod type), single head or multiple head threads, and the accuracy grades are generally A, AA, AAA.

According to whether coolant is added during cutting, it can be divided into dry cutting hob and trial cutting hob.

The general processing range is as follows:

Types: Holes and Shanks

General range of modulus: 0.25 to 33

Diameter control DP range: 0.75DP to 100 DP

Maximum diameter: 330mm

Maximum length: 380mm

Accuracy class: AAA, AA, A and B according to DIN/GB

Involute spline hob

Generally, involute spline standards include: DIN 5480, DIN 5482, ANSI B92.1, B92.2, BS3550, GOST-6033, GBT3478, etc.

Hobs for parallel side splines

The production of hobs conforms to various standards DIN 5461, DIN 5462, DIN5463, DIN5464, DI5465, DIN 54 71, DIN 5 472, DIN 9611, ISO 14, UNI 220, UNI 221, UNI 8953, GB/T1144-2001), etc.

type

characteristic

application

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.

Sprocket hob

Hobs for automotive and industrial roller chains are produced according to various 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 important type of worm hob is the worm type, such as ZI, ZN, ZK and ZA.

Single or multiple head hole and handle types are used, and the lead angle is generally up to 45 °.

Hobs have two cutting modes: tangential feed and radial feed.

Hobs with special tooth profile

Hobs with special tooth shapes for various parts can basically be used as long as the external gears are generated and processed.

Straight tooth synchronous pulley hob

Produce synchronous pulley hobs for various belts and pulleys of involute and HTD profiles;

Top cut and non top cut design are adopted.

Common models of pulley:

Involute profiles such as “T” and “S”

HTD、MXL、XL、L、H、XH、XXH

Heavy double cutting hob

Produces specially designed double cut hobs, reducing cutting time by adding specially designed cutting edges in grooves.

These are designed for gears with 5.5 modules and above.

Benefits:

Greatly shorten cycle time;

Easy to implement;

Reduce hob wear;

Hobs can be used for manual and CNC hobbing machines.

Dry cutting hob

It is used for high-speed cutting on CNC gear hobbing machine to achieve higher productivity.

The length of cutting edge of this kind of hob is very long, and the number of grooves of the hob is large.

This can improve the processing life of the hob in one grinding.

It is very suitable for use in large batches of automatic production lines.

It is recommended to use the specifications of the hob, such as diameter, number of grooves and heads, and cutting parameters.

The goal is to obtain the shortest cutting time and the longest life.

Benefit:

Reduce cycle time;

The number of parts sharpened each time increases;

Less inventory;

Less variables to achieve smooth production;

Increase factory capacity without increasing investment in land, machinery and manpower;

Reduce the cost of each component.

Application:

Dry and wet cutting;

Type of hole and handle;

Single thread and multi-thread;

Large capacity parts, such as two-wheeled vehicles, automobiles, gear rings, chain wheels, etc;

Easy to implement.

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