Development within mobile hydraulics continues to focus on higher energy efficiency, more compact machine design and improved controllability. One of the latest solutions in this area is the new generation of tandem axial piston pumps for hydrostatic transmission in off-highway machinery.
The Danfoss MP1T is a dual transmission pump developed for closed hydrostatic systems in applications such as compact loaders, tracked vehicles and other machines using so-called dual-path drive systems. The pump combines two separate transmission pumps in a single housing, reducing installation space and simplifying the hydraulic layout of the machine.
Dual transmission pump for dual-path systems
In many modern work machines, the left and right sides are driven independently. This applies to:
- compact loaders
- skid steer machines
- tracked vehicles
- certain forestry machines
- self-propelled special-purpose machines
For these applications, dual transmission pumps are often used, where each pump section drives its own hydraulic motor and drive side.
The benefits include:
- improved maneuverability
- more precise steering
- smoother turning functionality
- improved traction
- greater low-speed control
By integrating both pumps into a tandem solution, manufacturers can also reduce both weight and installation length compared to two separate pumps.
What is a closed transmission pump?
The MP1T is developed for closed hydrostatic transmission systems.
In a closed system, the hydraulic oil mainly circulates between the pump and hydraulic motor in a closed loop. The pump controls both flow and driving direction by changing its displacement.
This means the transmission pump functions as the machine’s hydrostatic gearbox and regulates:
- speed
- driving direction
- torque
- acceleration
This type of hydrostatic drive is used where high precision and stepless control are important.
Variable axial piston pump with high efficiency
The MP1T is a variable axial piston pump, meaning the pump flow changes by regulating the angle of the swash plate.
When the pump displacement increases:
- flow increases
- the machine accelerates
- more driving force is generated
When the angle decreases, flow is reduced and the machine slows down.
According to Danfoss, the pump has been developed with a focus on high mechanical efficiency and lower internal energy losses, helping reduce both fuel consumption and cooling requirements.
Electronic control for modern hydrostatic drive systems
An important part of modern transmission pumps is the control system. The MP1T uses several types of control depending on machine requirements, but the main focus is electronic displacement control.
This means pump flow and driving direction are electronically controlled via the machine’s control system.
Benefits include:
- smoother driving feel
- faster response
- precise low-speed control
- improved energy efficiency
- easier integration with CAN bus and vehicle control systems
The pump is also available with Forward-Neutral-Reverse (FNR) control, commonly used in hydrostatic drive systems for construction machinery.
Compact design simplifies machine construction
Installation space is a critical factor for machine manufacturers. The tandem design makes it possible to integrate two transmission pumps into one compact unit.
Danfoss particularly highlights:
- shorter installation length
- simpler hose routing
- improved service access
- cleaner machine layout
The compact design becomes especially important in small and medium-sized machines where space is limited.
Focus on efficiency in future mobile hydraulics
The hydraulics industry is increasingly influenced by demands for lower energy consumption and improved total operating economy. As a result, new hydrostatic transmission systems are being developed with a focus on:
- higher efficiency
- reduced heat generation
- smarter electronic control
- more compact machine design
- improved operator feel
Tandem transmission pumps for closed hydrostatic systems are therefore becoming an increasingly important component in future construction and special-purpose machinery.
