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: Hitachi® hydraulics excavator with top drive, single raised drive lug and dual asymmetric roller undercarriage design.
The third article in this series focuses on the EX2600, EX3600 and EX5600 range of Hitachi® hydraulic excavators. The features that define this style of undercarriage include:
- Top drive type
- Single, raised track shoe drive lug configuration
- Dual, asymmetric track shoe roller path configuration.
This undercarriage design is optimised for strength and durability, with a strong emphasis on production cost savings due to its unique design. Progress Mining has supplied undercarriages for these platforms to customers operating in coal, gold, copper, iron, anthracite and oil sand mines across Africa, Australasia, Europe and North America.
Above: Hitachi® 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 top drive design minimises backlash in the system in the early stages of undercarriage 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 track shoe design features optimised section thicknesses. This design feature minimises component mass, reducing the amount of metal needed for production. This design has been optimised to lower production costs without compromise, maintaining the desired strength and stiffness required for optimal component functionality.
- The dual roller path design results in greater contact area between the rollers and the track shoes. This decreases the contact pressure and subsequent wear of both components.
- The asymmetric track shoe design allows for continuous roller path engagement, helping decrease component wear.
- The faceted sprocket design allows the track to be driven under friction in low torque scenarios without the drive lugs engaging. This design feature minimizes drive lug wear.
As with any engineering design, there are certain aspects of the undercarriage configuration that may present disadvantages:
- The single drive lug design means contact pressure and resulting wear rates are higher than a dual drive lug system. This increases wear over time.
- The top drive means that only one drive lug is engaged at a time, leading to higher localised stress at the engaged drive lug.
- Engagement issues can be hard to diagnose because the drive lug engagement is hidden in this design making easy visual inspection difficult.
The undercarriage design featured in this article does not apply to the larger EX8000 Hitachi® excavator platform. The EX8000 undercarriage design is very similar to the Komatsu® design with its top drive, single roller path and dual raised drive lug track shoes that was featured in the second article of this series.
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®
Read article 2 in the series: Undercarriage Design Series: Komatsu®