Worm gear sets according to SPN standard

SPN Worm gear sets are available in different material combinations. Depending on the application, we will work with you to select the right material. Special cast alloys for low-speed, high-load drives, plastic compounds for a very smooth-running drive and many more. Talk to us!

Worm gear sets consist of a worm with a helical part. While the worm wheel is a toothed disk that fits snugly against the worm. The worm drive enables a high transmission ratio with a compact design. The worm rotates while the worm wheel moves in a perpendicular direction to it. This configuration provides high torque transmission and enables self-locking. Worm gear sets can be made from various materials such as steel, bronze, brass or plastic. The choice of material depends on factors such as hardness, wear resistance and application environment. For the worm gear, the tooth width and the type of forging influence the contact surface and therefore the load capacity. A sufficient tooth width is important in order to distribute the transmitted load evenly and minimize wear. The pitch angle (ratio of the number of teeth to the unwound diameter) of the worm determines the transmission ratio between the worm and worm wheel. A larger pitch angle leads to a lower transmission ratio and vice versa.

The diameter and length of the worm shaft are determined according to the load requirements and space restrictions in the application. Larger diameters offer greater stability and load-bearing capacity. The lead angle of the worm determines the transmission ratio and the efficiency of the worm gearbox. Its direction, left or right, also influences the direction of rotation between the worm and worm wheel.

A worm gear set, also known as a worm gear transmission, is a special form of transmission that comprises a worm shaft and a worm gear.

  • First of all, the tooth form is specified with the module (m), which indicates the distance between the teeth (pitch px).
  • Together with the diameter of the worm shaft, this module determines the center pitch angle (γm) of the worm.
  • Furthermore, the pressure angle (α) between the worm and the gear is defined, which indicates the inclination of the worm flank.
  • Another important parameter is the number of teeth (z) of the worm gear.
  • This is also responsible for the number of teeth on the gear wheel.
  • The pitch (p) of the worm indicates how far the worm moves forward axially per revolution.
  • The profile displacement (x) describes the displacement of the worm wheel profile along the worm wheel axis.
  • Finally, the transmission ratio (i) indicates the relationship between the speed of the worm and the worm wheel, which determines the basic function of the worm wheel gearbox.

worm wheels

Manufacturing process tangential and hobbed
Division single-and multi-start
Module up to 8 mm
Number of teeth 2-9999
Component length up to 750 mm
Workpiece diameter up to 400 mm

worm shafts ground

Manufacturing process profile grinding
Division single-start and multi-start parts
Module up to 7 mm
Tooth length up to 400 mm
Workpiece diameter up to 110 mm

SPN worm shafts milled

Manufacturing process profile milled
Division Single and multi-start parts
Module up to 10 mm
Tooth length up to 400 mm
Workpiece diameter up to 110 mm

backlash-free worm drive

The geometric design of a worm drive offers the advantages of a crossed shaft angle. In addition, the large worm gear is suitable for a hollow shaft or for passing through additional gear stages. With a classic worm drive, the backlash increases due to the initial running-in of the worm wheel with the worm shaft.

The running-in of the worm wheel is desirable and increases the load-bearing capacity of the drive. This property is unsuitable for a backlash-free drive, and worm drives are sometimes readjusted after the gearing has run in.

SPN has succeeded in adapting the gearing geometry and material selection of a worm gear set in such a way that the run-in of classic gearing no longer occurs. The components are also designed in such a way that a torsional backlash of less than 1 arcmin can be set. With this further development, the geometric advantages of worm gearing can be combined with zero backlash and rigidity.

Your contact for SPN worm drives

Contact Person

Anton Lösch

Telephone: +49 9081 214-134

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