Mitigating risks in agricultural hydraulic hose applications

08 December, 2017

Just as the human body contains veins for transporting blood to vital organs, many mobile machines contain hydraulic hoses that deliver vital fluid to system components to ensure efficient machine operation. The hydraulic hose is a critical component, if it fails then the whole system can come to a grinding halt. The service life of the hose can be severely impacted by the environment that the machine operates in and globally you will find agricultural mobile machines working in some very hostile conditions.

For operators the number one priority is to ensure that equipment such as harvesters and combines deliver productivity and stay functional. Continuous uptime is extremely critical, since unscheduled downtime can result in huge operating losses being incurred. What’s more, studies show that 31% of hose failure are what is called ‘inside out’ primarily due to aging.

Consider the Impulse cycles

At some point in a mobile machines operational life, system components will degrade and eventually wear out. With a preventative maintenance schedule, downtime can be mitigated for and system component life times can be extended to maintain operational capabilities. However, despite such a programme hoses will need to be replaced as their lifetimes are not infinite. When it comes to hydraulic hoses the qualification of expected service life usually follows impulse cycle testing to established industry standards.

Standard EN857 Type 2SC hoses are qualified up to 200,000 impulse cycles and whilst this is significant, hose manufacturers should be actively looking to offer hoses that extend this significantly. It’s not uncommon at Eaton for our engineers to be working on hose lifetimes that significantly enhance performance. Indeed, Eaton’s EC881 hose has a specified impulse life of one million cycles, achieved through next generation inner tubes that offer extreme protection and reinforcement. For OEM’s this enables them to gain competitive advantage by offering their customers longevity on machines, and for operators one million cycle hoses deliver extended uptime and operational efficiencies.

Consider the bend radius

When it comes to specifying the hydraulic hoses that are needed on a mobile machine, the minimum bend radius is an important factor. If the hose does not have the required bend radius it could become unduly stressed or distorted thereby shortening the service life. We are increasingly dealing with customers who are designing mobile machines to be more compact, indeed the market trend is pushing for this. As these machines get smaller there is a need for systems components to be more compact in order to be installed in less available space.

Standard EN857 Type 2SC hoses are proving to be unsuitable in this new environment as they have to travel a greater distance in order to be routed around the spaces where they simply won’t fit due to restrictive bend. For the OEM this means that the amount of hose needed for the work around is greater – this increases build cost as a greater quantity of hose is required. This extra cost has to be passed on to the end customer and the price of the machines may well rise. Increasing the cost of a capital purchase can prove to be prohibitive.