Spindle nut
A spindle nut , sometimes also called a motion nut , is a component of a trapezoidal screw drive , ball screw drive or roller screw drive in linear technology .
Structure of a recirculating ball nut
The spindle nut of a ball screw drive, also known as a recirculating ball nut , consists of a nut body with incorporated ball circuits, a ball return channel and so-called return sleeves (tubes), which are made of steel or plastic depending on the model and whose attachment to the nut can vary.
The nut body can be designed with or without a flange and offers space for several load-bearing ball circuits, the load rating of the entire ball screw drive depending on the number of load-bearing balls inside the spindle nut. Spindle nuts for ball screw drives are available in a standardized design as DIN flange nuts or DIN double flange nuts , but are also offered in supplier-specific standards .
In the case of ball return (often also referred to as ball return), there are internal and external ball return in terms of design. The internal ball deflection has the smaller installation space due to its principle. Inserts in the nut lift the balls slightly at the end of the thread so that they can be returned to the previous thread above the outside diameter of the spindle. With the external ball return, the ball is completely lifted off the spindle and returned, for example, through a return sleeve.
Recirculating ball nuts are offered to match the corresponding spindles with different pitches and different diameters. Since ball screws are still relatively little standardized, the dimensions of the standard spindles from leading manufacturers vary considerably.
The nut size is specified on the basis of the nominal diameter of the threaded spindle and the pitch of this spindle, with the standard range on the market from so-called miniature nuts for spindle pitches of approx. 2 to 16 mm with a nominal spindle diameter between 6 and 20 mm up to nuts with pitches of 50 mm and nominal diameters of up to 125 mm is sufficient. For technical reasons, the real outer diameter of the recirculating ball nuts is, of course, considerably higher than the nominal diameter of the associated threaded spindle.
The length of the spindle nut depends, among other things, on the number of load-bearing ball circuits that are present in such a nut, the overall geometry also including the return channel, which returns the balls to their starting point and thus closes the circuit in which the balls circulate.
Structure of a roller nut
Web links
- Representation of different nut designs (Steinmeyer GmbH & Co. KG)
