Electrified drivetrain for skid steer loaders

Skid steer loaders are among the machines for which drive technology must be designed to be both particularly compact and resilient. The requirements are clearly defined: limited installation space, high tractive force and reliable performance values in daily use.

With this in mind, an electrified drivetrain was developed that extends existing technology without fundamentally changing it. The design combines conventional and electric components to create an integrated solution that fits into existing machine concepts.

ZF Friedrichshafen combines axles with a three-shaft gearbox

The system is based on two conventional axles, which are also used in classic drive concepts. They are supplemented by a three-shaft gearbox that structures the power transmission within the system. ZF Friedrichshafen thus utilises an architecture based on proven elements. The advantage lies in the continuity: existing components are retained and supplemented by new elements. This reduces the customisation effort and facilitates integration. The three-shaft gearbox plays a central role. It connects the individual components and ensures a harmonised distribution of forces.

Electric motor with 20 kW continuous power and 36 kW peak power

The electric part of the drive is realised by an electric motor. This delivers a continuous output of 20 kilowatts and achieves a peak output of 36 kilowatts. The system is designed for skid steer loaders in the five to five and a half tonne range. This covers typical applications in this machine class. The performance data is based on the requirements that are made in daily operation. The achievable characteristic values also meet these requirements. A tractive force of around 80 percent of the machine weight and speeds of up to 20 kilometres per hour are possible. This means that the operational capability is maintained in comparison to conventional drives.

Liquid cooling enables the same installation space

A decisive factor in the integration of electrical components is the available space. Skid steer loaders only offer limited installation space, which is why additional technology is difficult to accommodate. The solution utilises liquid cooling for the electric motor and the inverter. This efficiently dissipates the heat generated without the need for larger heat sinks or additional components. The result is a drivetrain that remains comparable in size to a conventional system. For manufacturers, this means that existing platforms can continue to be used.

Interaction of the components in the electrified drive

The function of the system results from the harmonised interaction of all components. Axles, transmission and electric motor do not work in isolation, but as a unit. ZF Friedrichshafen pursues a systemic approach. The electrical component complements the mechanical structure and takes on defined tasks within the driveline. This ensures that the overall function remains stable and predictable. The design of the electric motor is deliberately tailored to the intended use. Neither oversizing nor unnecessary complexity are at the forefront.

Properties of the drivetrain at a glance

The main features can be summarised as follows:

• two conventional axles as the basis of the system
• Three-shaft gearbox to control the power transmission
• Electric motor with 20 kW continuous power and 36 kW peak power
• Application range for skid steer loaders up to around 5.5 tonnes
• Liquid cooling for constant power in a compact design

Integration into existing machines without conversion

The drive train is designed so that it can be integrated into existing machines. Fundamental changes to the design are not necessary. ZF Friedrichshafen is thus presenting a solution that is orientated towards the real requirements of the industry. Existing technology is not replaced, but extended. As a result, economic efficiency is maintained while new drive concepts can be realised at the same time. This approach is particularly relevant in the compact segment. The machines must function reliably, while at the same time becoming increasingly efficient and flexible. The electrified drive train is a technical option for this.