Electronic Parking Brake Switch Lubrication-Case Study
Small applications of synthetic grease are very important throughout a modern vehicle and the interior is no different. In this case study we will focus on an Electronic Parking Brake (EPB) switch lubrication application; sometimes EPB devices are referred to as E-Brake. Throughout the interior of a vehicle, lubricants reduce noise and help to convey a quality feel in hand operated components, including electrical switches and dials.
A synthetic grease will also extend the operating life of components, ensuring high levels of reliability and customer satisfaction.
An automotive tier one supplier contacted us for assistance with improving the tactile feel and extending the functional life of their new design of EPB. The three issues faced in the EPB design were:
- Surface wear of the PA-6 plastic and the brass coated cylinder.
- Damping of the brass on plastic surface movement to improve the perceived value of the EPB operation.
- Lubrication of the PA-6 on PA-6 movement (see gif below).
A gif of the movement involved:
Challenges
One grease for all three lubrication tasks is preferred to help keep manufacturing and quality control relatively simple; also using one grease type throughout the device helps with purchasing costs.
Plastic compatibility should be considered; there is always a small risk of grease causing plastics to swell, crack or discolour. This risk can be mitigated if of course you have used the same product on similar materials before or the grease used is classed as inert, however a plastic compatibility test is recommend to ensure no problems occur. We have an article on grease vs plastic compatibility if more insight is required.
Solution
- A low viscosity synthetic damping grease to ensure the mechanism operates smoothly, that is also suitable for metal on plastic lubrication.
- A Polyalphaolefin (PAO) based grease with PTFE is well suited for lubrication of the rolling and sliding action of the surfaces.
- The damping grease must be durable, not dry out and improve the functional life of the device.
Product Selection
Rheolube 362HB
The Rheolube 362HB range is available in large containers for manufacturing, e.g. 35lb pail (approx 16kg) or 175kg/385lb drum. Tubes of Rheolube 362HB are available at our online shop.
Results
The addition of a the Rheolube 362HB reduced any internal PA-6 surface wear during EPB operation so the device met the functional life requirements of the tier one automotive supplier and the OEM. The application of the synthetic grease also gave the EPB an improved tactile feel as intended by the automotive supplier.
THE APPLICATION OF rheolube 362HB greatly improved the functional life and perceived value of the EPB switch.
As already mentioned in this article, always consider the potential plastic compatibility issues when using any grease from any manufacturer.
Take a look at our other case studies.
