Seals | SCHNEEBERGER Application Manual

1.8.1 Function of Seals

The seals on SCHNEEBERGER MONORAIL guideways protect the carriage and rolling elements from foreign matter ingress, such as dust, chips, and coolant.

To ensure optimal function of the guideway seals, the following factors are crucial:

Complete configuration and correct installation of scrapers
Supplying lubricant to the sealing lips to prevent stick-slip effect, lip rollover, and wear
The smoothest possible wiping surface without projecting edges, e.g. using ground surfaces and using guide rails with fixings from below, or using a MAC cover strip

1.8.2 Seal Types

Transverse Scrapers

Cross wipers seal the carriages at the front in the direction of movement. The wipers are located on the two ends of the carriages and are double-lipped in design. A stable sealing lip points towards the outside of the carriage and is used to wipe away swarf and dried on dirt. A thin, friction-optimised sealing lip points inwards. It is used to minimise the discharge of lubricant.

Transverse scrapers are designed as contact seals. This means that reliable operation requires normal force F_N, which generates friction force F_R.

Function of the transverse scraper (cross-section) in the direction of motion (yellow arrow x). F_N = Normal force, F_R = Friction force

Legend:

1 Direction of movement

2 Dirt

3 Guide rail

4 Lubricant

5 Carriage interior

6 Cross wiper

F_N normal force F_R friction force

Longitudinal Scrapers

Longitudinal scrapers are seals arranged in the direction of motion, used to seal the rolling element recirculation channels.

Longitudinal scrapers (green) and transverse scrapers (red) on the carriage

Smooth-Running Transverse Scrapers

Smooth-running transverse scrapers are used to reduce thrust in applications with less contaminant accumulation. This design optimizes friction characteristics while maintaining basic sealing function.

Additional Transverse Scrapers

Under special working conditions, such as severe contaminant accumulation, chip impact, or coolant influence, additional sealing devices can be installed.

Single-Lip Additional Seal

Made of NBR or high-strength fluorinated rubber

Non-Contact Metal Attachments

Suitable for extreme environmental conditions

1.8.3 Friction of Different Seals

For contact seals, there is a direct relationship between friction force F_R and sealing efficiency. Good sealing efficiency typically means higher friction force.

Comparison of driving force F_V (%) for different scraper variants on ball guideway BM 35 example

Legend:

1 Smooth-running scraper QL (~80%)

2 Standard scraper QN (~100% baseline)

3 Standard + additional scraper ZBN/ZBV (~170%)

Y-axis: F_V [%] - Driving force (percentage relative to standard scraper)

Note: Higher values indicate greater friction force but better sealing effect

Selection Recommendations

Seal selection should be based on actual working environment. Excessive sealing increases friction force and cost, while insufficient sealing leads to premature wear. It is recommended to consult SCHNEEBERGER technical personnel for optimal recommendations.