SPRINGLIDE™ Energised Bearings: for the Vehicles of Tomorrow
Traditionally, for plain bearings, manufacturing tolerance ranges can cause high friction variation. To keep the friction low and reduce the variation, large clearance is required, which can cause rattle noise. The SPRINGLIDE™ Energised Bearing solution, with consistent friction throughout the tolerance range, eliminates the need for clearance, which eliminates the rattle noise.
Saint-Gobain engineers solved this issue by listening to their customers in the automotive industry so they could fully understand the problems associated with manufacturing tolerances. To act as a sliding element, the solution needs the low friction properties of the PTFE layer in NORGLIDE® Bearings. To eliminate problems with tolerance ranges, the tolerance compensation properties of RENCOL® Tolerance Rings are needed. The conclusion, then, was to combine the two solutions to give the best of both.
Figure 1: The SPRINGLIDE™ Energised Bearing styles currently available. Starting from the top left; spring finger, slotted rib, stamped and wave design.
Reducing Rattle Noise
To validate the SPRINGLIDE™ Energised Bearings benefit over current solutions, a sliding system was tested with a SPRINGLIDE™ Energised Bearing and an injection moulded plastic bearing. The housings were rigidly attached to a vibration shaker in three different orientations that allowed the front-back, side-to-side and up and down orientations to be interrogated individually. The test was carried out in high and low frequency bands to provide a more accurate representation of the acceleration levels in the two ranges. When the sliding system was vibrated front to back and left to right, the results show a significant decrease in rattle of about 8 dB(A) for the SPRINGLIDE™ solution at low frequencies and a smaller decrease for the high frequency band. The up-down vibration test revealed no significant difference between the two solutions at either frequency range. The SPRINGLIDE™ solution also provides spring damper characteristics to absorb vibrations between the shaft and housing.
The overall and significant reduction in rattle noise for the SPRINGLIDE™ solution means a quieter drive, reducing the amount of stress caused by the daily commute.
Figure 2: Measurement of rattle noise from two sliding systems, one fitted with the injection moulded plastic and another unit retrofitted with the SPRINGLIDE™ sprung finger bearing. The units were excited with vibrations in each spatial axis, individually.
Increasing Tolerance Compensation
To validate the tolerance compensation ability, a SPRINGLIDE™ Energised Bearing was tested against an injection moulded plastic sleeve at three different clearance conditions that represent a typical manufacturing tolerance range. The result shows a great improvement with lower friction, more consistent performance and a large reduction in stick-slip. All three of these factors provide a luxurious, quality feel that will make the driving experience that much more pleasurable.
Figure 3: The push/pull forces on a head restraint pillow for the minimum, nominal and maximum clearance conditions to be expected from typical mating components.
Making Small Parts.
Making a Big Difference.
Elimination of grease
Simple, in line, fixing with a press fit saving space and weight
Compensates for large manufacturing tolerances and misalignments
Combines materials in ways to optimise assembly
Clearance free fits to reduce the risk of rattle
Vibration damping and isolation for a smoother performance
Maintenance free throughout its lifetime
Friction control over product lifetime with low coefficient of friction