There are many different styles of undercarriage available in the market, each with unique design features that set them apart. Progress Mining supplies all undercarriage types giving us a unique insight into what works best in different situations. To illustrate how these undercarriage styles differ we are posting a series of articles, each a spotlight on a particular undercarriage style, outlining key features, advantages and disadvantages.
Above: Komatsu® PC8000 hydraulic excavator with top drive, dual raised drive lug and single roller path undercarriage design.
The second article in this series focuses on the PC3000, PC4000, PC5500, PC7000 and PC8000 range of Komatsu® hydraulic excavators. The features that define this style of undercarriage include:
- Top drive type
- Dual, raised track shoe drive lug configuration
- Single track shoe roller path configuration
This undercarriage design is strong and durable. Progress Mining has supplied undercarriages for these platforms to customers operating in coal, gold, copper, anthracite and oil sand mines across Africa, Australasia, North and South America.
Above: Komatsu® undercarriage design illustrating the different design features.
This undercarriage design has proven its efficacy over time, the following advantages show why it is used in many mining fleets:
- The dual drive lug design results in a greater contact area, which helps decrease the contact pressure of components on engagement, thus reducing subsequent wear.
- Top drive minimizes backlash in the system helping reduce roller path wear particularly in the early stages of component life. Backlash is the distance between the non-driven shoe and sprocket drive lug flanks. The larger the distance the higher the sliding between the shoe and sprocket roller paths is during a change in sprocket rotation.
- The single roller path design results in consistent wear rates across the length of the roller path.
- The design features exposed engagement which allows for easy component inspection and identification of engagement issues when they arise. This makes wear measurements easier to record and component life projections more reliable.
As with any engineering design, there are certain aspects of the undercarriage configuration that may present disadvantages:
- The raised drive lug configuration results in reduced room for wear in the system. Forced engagements rapidly accelerate drive lug wear ultimately leading to lack of drive.
- The single roller path design means contact pressure and resulting wear rates are higher than a dual roller path system because there is less total contact area.
- The single roller path design also results in non-continuous roller engagement, causing subsequent fluctuating loads on rollers increasing wear over time.
- The raised track shoe drive lug design places a limitation on the roller axle diameter due to lug interference in the later stages of component life. This results in inferior bush to axle contact area compared to other platforms at equivalent weight classes.
Progress Mining supply all undercarriage types to many different mine sites across the globe. The knowledge and insights gathered over the years puts our team in a position to understand the complexities of each undercarriage design. Using the data gathered from countless Condition Monitoring inspections in parallel with CAD engagement analysis, our team is well placed to analyse your fleet and provide recommendations based on your needs.
To find out how the team at progress Mining can help visit our Services page or email us at info@progressmining.com
Where ever mining is Progress Mining is there to help.
Read article 1 in the series: Undercarriage Design Series: Caterpillar®