DuraSense from Schaeffler comprises a guide carriage with sensors, as well as an electronic evaluation unit that allows up to seven sensors to be connected to it. Why the sensors? For monitoring the lubrication conditions of the linear guide carriage. During a defined reference run, the lubrication conditions for each guide carriage are continuously recorded from the vibration energy emitted. These conditions are checked against a limit value known as the "lubrication indicator" and if the described limit value is exceeded, relubrication takes place.
DuraSense provides three different methods of relubrication. In its basic development stage, the system can be used to monitor, assess and, if necessary, optimise manual relubrication or interval lubrication systems. The Schaeffler DuraSense sensors and the relubrication system work independently in this case. In the automatic variant, the Schaeffler DuraSense sensors and the lubrication system are connected in a single control feedback loop. Fixed lubrication intervals are omitted and the lubrication system is activated only according to the lubrication indicator. Suitable lubrication systems include the Concept2 and Concept8 automatic lubricators from Schaeffler, and central lubrication systems.
There are two ways in which lubricating impulses can be triggered. The first is for the evaluation unit to deliver 24V trigger signals for each of the seven channels. The 24V outputs can be connected to both the relubrication units and the machine control system. The second option allows the lubrication indicator value to be emitted as a 4-20mA signal for each of the seven channels as an alternative to 24V signals. Using this variant makes it possible for lubrication conditions to be continuously monitored, and for the relubrication function to be adjusted with even greater flexibility. The signal can also be used for further analyses such as calculating the future remaining useful life.
With Schaeffler DuraSense, potential challenges emanating from insufficient lubrication and over-greasing are reliably prevented, resulting in lubricant savings of up to 30 per cent. All achieved at optimum load, as well as reducing the number of failures caused by contamination. The latter is due to the fact that, if foreign bodies enter the carriage through contamination or the carriage is contaminated by a liquid medium, lubrication impulses are triggered for as long as it takes for the contamination to be flushed from the carriage. Without this control loop, the linear guidance system would remain in operation with contamination in the rolling contacts until the next planned relubrication interval - and so would suffer corresponding initial damage, perhaps much worse.
For more information about DuraSense please visit www.schaeffler.co.uk.