Bearing Active Preload Device


Fully Variable Active Preload Device

Technology abstract

Mechanisms are crucial to spacecraft for scanning, tracking, deployment of solar arrays and instruments, and platform stabilisation functions. UK-based ESR Technology are specialists in tribology and mechanism design and have developed a device that allows bearing preload to be adjusted in service to preserve life and optimise performance. Originally developed for spacecraft mechanisms, the device can be tailored to any bearing application where axial preload needs to be varied.

- Private group -

- Helen Rogerson -

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Technology Description

BAPS active preload devices remove the compromise between surviving extreme loading and maximising performance/life under benign conditions.  The technology was originally designed for spacecraft mechanism applications to allow the preload applied to angular contact bearings to be reduced after the harsh environment of launch and then to be varied continuously in service.  This device can be used with a variety of actuators and in a range of configurations to allow the variable preloading of bearings.  It can also be applied to mechanical seals in order to create an active/adjustable mechanical seal for the most demanding applications.
The device replaces a conventional bearing housing with the active structure, which can then be actuated to apply a variable preload to the bearings which it supports.  The change in preload can be large in comparison to the overall load capacity of the bearing.  It can be used in a latching mode or in a continuously variable configuration and can remain unpowered.
ESR Technology have significant knowhow in relating to the design, production and testing of these active preload systems, obtained in the course of bringing the technology to maturity for the space industry, as well as being knowledgeable in all aspects of bearing design and operation.

Innovations & Advantages

The technology offers the ability to change the preload (and hence stiffness and torque characteristics) of a pair of angular contact bearings when in service.  This is particularly advantageous for applications where the bearings are inaccessible or unmaintainable.  It is also particularly suited to applications that see large variations in loading, but require long life.  The low mass and low power consumption of the device are also attractive for high end applications such as aerospace.
The technology is ideal for high end applications where there are a number of desirable technological and commercial benefits.

Further Information

Typical bearing sizes range from 10mm bore to 250mm bore, including thin section bearings.

Current and Potential Domains of Application

Various space missions and applications within the space domain.
Potential applications:

  • Optical pointing devices
  • Very long life applications (rotary scanning applications, flywheels)
  • Applications where intermittent high loads are experienced or variable bearing stiffness is desired
  • Mechanical seal applications (gap setting) and other bearing types

Potential domains:

  • Energy
  • Nuclear
  • Aerospace
  • Defence