This type of arrangement offers a very high reduction in speed and under certain conditions exhibits anti-backdrive characteristics. The basic efficiency of the system is low but increases in proportion to the angle of the teeth. The worm and wheel both have the same helix direction.
There is no standardisation of worms and wheels between different manufacturers. If one part is damaged it must be replaced by a strictly identical piece, this normally means having a copy made of the faulty piece. Manufacturers are free to choose the diameter of the thread and it is this determines the helical angle, the PCD (Pitch circle diameter) and distance between centres.
As their name indicates, these wheels allow the absorption of the backlash which can exist in a classical worm and wheel setup. Springs are placed in channels between two wheels of the same dimension, which are attached together with a circlip. During assembly the two discs should be offset by a few degrees, this compresses the springs and allows them to absorb any backlash.
Note, anti-recoil wormwheels can be only used with single start worms.
Yes we can supply custom made worm and wheel pairs, please contact us on +33 (0) 437 496 496
Four principal parameters characterise a worm
The actual helix angle is difficult to determine. The direction of the teeth is done visually. Hold the gear vertically, if the threads go up to the left, it is a left handed thread, if they go up to the right, it is a right handed thead.
|left hand threaded||right hand threaded|
To measure the pitch, measure the distance between two threads.
To count the number of threads, it is necessary to count the number of starts by looking at the end of the thread or into the bore.
|Don't count the starts like this||They should be counted in this direction|
There are 4 principal characteristics that define a wheel
The first three parameters are determined by the formulae
de = m x (Z+2) or m = de/(Z+2) or Z = (de/m)-2
The actual helix angle is difficult to determine. The direction of the teeth is done visually. Lay the the gear on a table, if the threads go up to the left, it is a left handed thread, if they go up to the right, it is a right handed thead16 The helix angle is difficult to measure. The only way is to assemble the wheel with the worm that was made for it (same module and same number of threads).
This worm with 4 threads will not function with the gear with only 1 thread.
|However this worm and wheel are compatible.|
58, chemin de la Bruyère
LYON - FRANCE
Tel : +33(0)4 37 496 496
Fax : +33(0)4 37 490 055