Find out how the spindle (also called a ‘lead screw’) pitch is connected to an actuator’s efficiency and self-locking ability, and why an actuator will always provide the same efficiency output, regardless of the load applied. Our expert Hunter Stephenson explains the essentials in this video.
The spindle pitch is the distance that a nut travels when rotating 360 degrees on a spindle. So, if the spindle pitch is 12 mm, it means that the nut travels 12 mm on one spindle revolution.
The higher the spindle pitch, the more efficient the actuator becomes since there is less friction between the nut and the spindle.
The stroke length of an actuator refers to the maximum distance the actuator will move or extend. This is the range of linear motion from its fully retracted position to its fully extended position. In essence, it is a measure of how far the actuator's rod or piston can travel in a single motion.
The stroke length of an actuator depends on the length of the spindle. LINAK actuators are generally very versatile and stroke lengths up to 1.20 meters can be specified according to customer requests. But, when considering actuators with long stroke lengths, there are some limitations. When running long strokes in push, we reduce the maximum load specification. The reason is that the higher the load and the further away from the inner position the nut travels on the spindle, the bigger the strain is on the actuator.
It is possible to add a safety nut in an actuator, for machinery where safety is a high priority. If, for example, the thread inside the nut on the spindle wears off due to wear and tear, the nut will immediately carry the full load and the actuator travels inwards. In this case, the actuator can no longer run outwards, and it must be replaced.
Did you know?
A high-quality spindle is the essence of achieving an optimal actuator performance. The iron bars used for LINAK® spindles are carefully selected before rolling the spindle threads.
Which spindle type and spindle nut to select depend on the load and performance requirements of the actuator. For example, a long spindle nut is better for lifting heavy loads. To obtain a long and reliable service life for actuators with high spindle pitches, more tracks are added to efficiently distribute the forces from the industrial application to the spindle and the nut.
The core diameter of the actuator spindle (not including the tracks) determines the strength of the spindle, thus the actuator.