Spur gear module 2.5 z=21 with hub

Product Description

Spur gear module 2.5, z=21, with hub

The spur gear module 2.5 shown, 21 teeth, with hub, is a basic component of module drives - it meshes with any other gear or gear rack (toothed rack) of the same module and pressure angle 20°. The gear is made of C45E steel (EN 10083-1); the involute tooth profile and 20° pressure angle ensure smooth, quiet meshing with gears or racks of the same module.

Technical data

Frequently asked questions

What is the difference between a gear with hub (PM) and a plate wheel (CM), and when should you choose which?

The hub extends the part axially and makes mounting on the shaft easier (more room for a key or a clamping ring), while the plate wheel is flat and lighter - it is chosen when the design already has its own bearing arrangement/mounting and the gear only has to transmit the meshing.

Do straight-tooth module gears have a specific mounting direction?

No, a straight-tooth gear is symmetrical and can be mounted either way round; direction only matters with helical teeth, where the helix angle must match the mating gear.

How do you cut a keyway in a module gear with a small hub?

In gears with a small hub, the keyway is slotted with great care so as not to weaken the wall above the tooth. If there is not enough space, we recommend dispensing with a standard key (feather key) in favour of mounting with clamping bushes (locking assemblies).

Can a module gear be ordered with a number of teeth outside the standard catalogue range?

Yes, in addition to ready stock we also produce CNC gears to order with a non-standard number of teeth, and for short lead times we additionally print them using 3D technology from glass-fibre-reinforced plastics.

Where is this product used?

Typical applications include conveyor drives, packaging machines, industrial automation and positioning systems using a gear and gear rack pair.

When placing your order, please check the current stock level of this gear - the lead time depends on it and is clearly stated according to the quantity available in the given warehouse.

Product photos are for illustrative purposes only.