Function, benefits and applications
A ball screw nut with teeth allows torque to be transmitted directly to the nut, thereby expanding the range of applications for ball screws in modern drive systems.
What is a ball screw?
Ball screws are among the key components of modern linear axes. They convert rotary motion into linear motion with high efficiency and precision.
A ball screw essentially consists of the following components:
- Threaded spindle
- Ball screw nut
- as well as the circulating balls, including the return system (ball return).
The balls run between the spindle and the nut within the threads, enabling low-friction power transmission through rolling friction.
Ball screw nut with teeth
In addition to the standard design, there are variants in which the ball screw nut is also fitted with teeth. This solution enables direct torque transmission to the nut – without any additional interface that could introduce inaccuracy into the system. It thus expands the possibilities for integrating the ball screw drive into complex drive systems.
What are the advantages of KGT nuts with teeth?
This design offers particular advantages for long axes in machine tool manufacturing, automation technology or custom machine construction – especially where the drive is not intended to be integrated into the spindle.
Key benefits at a glance:
- Direct torque transmission to the nut without any additional interfaces
- Reduced system complexity in the powertrain
- Greater system rigidity due to fewer transitions
- Compact design combined with high performance
- Improved integration options in complex drive systems
Basic principle of the ball screw nut with teeth
In a toothed ball screw nut, a toothed profile is integrated into the outer circumference of the nut to transmit torque via a positive-lock mechanism.
The gear teeth allow direct coupling to various drive elements, for example:
- Spur gear drives
- Timing belt drives
- Planetary gear
- Synchronised drives for multiple linear axes
As a result, the ball screw nut itself becomes an active component in the torque transmission within the drive system.
Toothed profile for timing belt drives on a ball screw nut
Types of Tooth Profiles
The selection of the appropriate tooth profile geometry depends on the application. Key influencing factors include, for example:
- Installation space
- Required torque
- Smooth running
- Economic aspects of manufacturing
Straight-tooth gearing (spur gearing) example on a trapezoidal nut
Straight-tooth gearing
Straight-tooth gearing is the most commonly used and structurally simplest type. In this design, the teeth run parallel to the nut’s axis. This type is particularly suitable for applications involving moderate speeds and high torques.
Typical features of ball screw nuts with face teeth:
- High load capacity
- robust force transmission
- relatively simple manufacturing
One potential drawback is increased noise at higher speeds.
Toothed profile for timing belt drives
For use with timing belts, specific profile geometries are employed, such as AT-profile tooth profiles in accordance with DIN standards. These enable backlash-free, positive force transmission and are particularly suitable for dynamic applications.
Such solutions are often used when:
- Larger axle spacings need to be bridged.
- Multiple axes are synchronized
- A decoupled drive unit is desired
Design Requirements
Integrating a tooth profile into a ball screw nut places increased demands on design and manufacturing.
Particularly relevant are:
- Coaxiality between tooth profile and ball screw raceway
- Concentricity of the tooth profile
- Suitable material and heat treatment for minimising wear
- Dimensions of the tooth flanks for the required torque
It must also be ensured that the tooth profile has no negative effects on the rigidity of the nut or on the ball return path.
Close-up of timing belt drive
Typical Applications
Ball screw nuts with teeth are used primarily in applications where the nut must be driven and compact designs with direct force transmission are required.
- A typical example is long axes in machine tools, where axial movements are required and the available installation space is often limited.
- Such solutions are also used in automation systems and handling equipment, where toothed nuts enable direct coupling to gearboxes or timing belt drives, contributing to an efficient design of the linear axes.
- Furthermore, ball screw nuts with teeth are used in special-purpose machines where individual drive concepts must be implemented. Particularly in customer-specific solutions, the tooth profile provides additional degrees of freedom in design.
Conclusion
The ball screw nut with teeth extends the classic ball screw concept with a direct interface for torque transmission.
This enables compact, integrated and application-specific drive solutions. At the same time, the fundamental advantages of the ball screw are retained: high efficiency, low friction and long service life.
This makes the toothed ball screw nut a high-performance solution for modern machine concepts with demanding requirements for precision and integration.
