The undercarriage is made up of the different key components used to drive your digger.

The undercarriage is made up of the different key components used to drive your digger. It comprises the following components: drive sprocket, chain, track plate, upper roller, lower roller and idler wheel.

Upkeep for the upper and lower rollers on your undercarriage

The lower rollers are located beneath the digger’s X structure. There are normally 7 rollers on each side for 20t diggers, two of which will be equipped with a guide chain. When using a caterpillar digger, it is common to have to cross wet surfaces, resulting in dust and earth accumulating around the rollers and causing leaks, particularly in winter. When water freezes, it damages the sealing joints between the axis and the roller, which makes them vulnerable to external particles. When the sealing on the rollers becomes damaged, this can lead to drive issues and can eventually damage your gearmotor reducer system. At Codimatra, we recommend that your undercarriage is thoroughly cleaned after each use in order to eliminate any dirt or earth, paying particular attention to the thick layer that can get caught up in the rollers.

The upper rollers are located above the chassis of your caterpillar digger. These rollers are used to support the chain in order to maintain the right level of tension. If your upper rollers become damaged, there is a good chance that your digger won’t be able to move in a straight line. The guidance and the tension will be poor, and you run the risk of your undercarriage becoming prematurely worn out. At Codimatra, we advise that these are cleaned after use in order to make it easier for them to rotate, just as we do with the lower rollers.

What are the idle wheel, the sprocket and the tension spring on your undercarriage used for?

The idle wheel is located at the front of the undercarriage and is not motorised, but is instead governed by the chain which causes it to turn. It is relatively uncommon for this wheel to break or to wear out, but this can still happen. At Codimatra, we recommend that you always drive with the idle wheel at the front, with this helping to absorb any irregularities in the surface through the tension spring. It is the geared motors of the drive system which will be called upon and which will need to be able to resist significant constraints. No particular maintenance is required for the idle wheel, but is required for the tension spring. Rust can quickly become an issue for the piston rod, meaning it is essential for this to be lubricated on a regular basis.

As far as the transfer reduction gears are concerned, it is essential that they are emptied regularly in order to eliminate any foreign bodies that might have found their way in there. This process couldn’t be easier: simply position the digger on a flat surface and then turn the caterpillar tracks until the drain plug is in its lowest position. If the oil is flowing freely, this indicates that the levels are fine. If the oil levels are too low, simply add more using the upper nut.

How to check the condition and the tension of your undercarriage

In order to ensure that your caterpillar digger runs smoothly, it is important to check the tension of the chain on a weekly basis. If the chain is too slack, wear will develop very quickly; on the other hand, if the chain is too taut, the force it will exert on the other components will be too strong. A correctly calibrated chain should sag slightly, which is referred to as “slack”. The slack will be indicated by the machine’s manufacturer. In order to stretch the chain, simply push on the idle wheel while injecting lubricant into the piston provided using a lubricant gun. To loosen the chain, you will need to remove some lubricant.

Even with regular maintenance, small pieces of metal will get caught up in the undercarriage and strike against each other: wear is normal and unavoidable.