Spindle drives with very short strokes - solutions

1. When is a stroke too short?

In cases of very short strokes, we refer to a short-stroke application. Short stroke describes a situation in screw jacks where the spindle’s travel distance is shorter than the lead screw thread. This creates specific challenges, especially regarding lubrication and spindle wear.

In short-stroke applications, part of the spindle remains permanently covered by the nut, preventing external lubrication and leading to insufficient lubrication, increased wear, and potential premature failure of the screw jack.

2. Technical challenges:

1. Insufficient lubrication: The permanently covered spindle areas are particularly vulnerable to insufficient lubrication since they are not regularly exposed to lubricant.

2. Increased wear: Without adequate lubrication, frictional resistance increases, leading to faster wear of the spindle and nut.

3. Maintenance effort: To minimize wear, more frequent maintenance intervals and careful monitoring of lubrication are necessary.

3. Solutions

1. Lubrication slots: Adding lubrication slots to the spindle or worm gear/nut can help distribute lubricant more effectively, eliminating insufficient lubrication.

2. Material selection: Choosing wear-resistant materials for the spindle and nut can extend the screw jack’s lifespan. Examples of maintenance-free combinations include plastic nuts on steel spindles.

3. Lubrication stroke: If the system allows, a lubrication stroke should be performed at regular intervals, where the spindle is extended beyond the length of the lead screw thread.