HELAX – Hydraulic Electric Linear Axis based on AX Technology
 Abbildung Hydraulic Electric Linear Axis based on AX Technology

written by Andreas Schnurrenberger on Friday, December 18, 2020

The new HELAX hydraulic-electric linear actuator produces straight-line movements in the 20–300 kW power range with precision and maximum efficiency, and it opens up new fields of application.

What is HELAX?

HELAX stands for Hydraulic Electric Linear Axis based on AX Technology. HELAX is a hydrostatic transmission that converts electrical energy into hydraulic energy with maximum efficiency and offers linear movements with very high precision. These application-specific system solutions not only set new technological standards, but also make a major contribution to sustainability.

No friction, no wear

At the heart of the HELAX is the special 4-quadrant-capable AX pump. Due to its unique design, it can map the entire operating range of servo motors with outstanding efficiency: even at very low speeds, the pump has almost no mechanical friction (starting efficiency up to 99%). The HELAX therefore masters the problem of generating large forces at close to zero speed – an operating point that is critical or even forbidden for many other linear actuators. Not so with HELAX, because where there is almost no friction, there is virtually no wear!

This hydrostatic transmission, in which friction has been very significantly reduced, thus facilitates precise control of large forces over small distances, as the inverse pendulum beautifully illustrates.

High power density, high working pressure and a minimum permissible speed that is exceptionally low: AX pumps ensure precise working motions, making them the ideal drive for decentralized linear axes.

Tailor-made solutions for a wide range of applications

In stationary plant we can see a wide range of potential applications: the highly efficient, low-friction hydrostatic transmission ensures precise control of linear movements, even with large forces and alternating load direction. This opens up new possibilities for the process technology used in production machines and testing equipment, with particular regard to component quality, throughput time and service life. Due to its modular design, the HELAX system solution can be easily adapted to a wide range of cylinder dimensions.

 Hydraulik löst die starre Kopplung elektromechanischer Antriebe auf.

Hydraulics eliminate the rigid connection needed in electromechanical drives: motor and pump can be positioned practically anywhere and be connected to the cylinder with pressure hoses.


In electrically powered mobile machines, losses are systematically reduced to a minimum. An example with numbers: while a conventional pump may exhibit a power loss of 5.2 kW, with the new Bucher Hydraulics AX pump the power loss under the same conditions is only 1.6 kW. Particularly with battery operation, this saves on enormously expensive battery capacity. Either the battery can be made smaller and cheaper, or its runtime can be extended by a corresponding amount, as modeling calculations and initial experience have verified.

The HELAX linear drive is also highly suitable for applications where energy can be recovered. In these cases the impact of the regenerative linear drive's high efficiency (overall efficiency up to 84%) on the energy balance is quadratic, in fact, thus enabling energy recovery in applications where previously this was not economically viable.

The on-board electronics ensure that the linear transmission can be easily controlled by the machine builder. The motion control signals are transmitted via CAN bus, for example: the software then converts the signals into the required movement. Users do not have to get involved with the detailed characteristics of the hydraulic system: they can concentrate fully on the function of their application. The hydraulic linear drive can therefore be easily integrated into the system just like any electric drive

Read the interview with Dierk Peitsmeyer, Product Portfolio Manager at Bucher Hydraulics on the topic of "Why do we need more efficiency in hydraulics?"

Highly efficient, electrically driven solutions

Thanks to its modular design, the HELAX system solution can be very easily adapted to a wide variety of cylinder types. The new AX pump from Bucher Hydraulics supplies the system with controlled flow rates without any throttling losses.

The HELAX benefits at a glance:

– Hydraulic linear drives with AX pumps provide dynamic and precise control even where large masses and high forces are involved
– Performance is comparable with or better than electromechanical linear drives
– Quiet, and low vibration levels
– Dynamic, precise and direct
– Highly efficient both as motor and as generator
– Low wear and low maintenance, rugged and reliable, just like a conventional hydraulic drive
– Lighter and more compact than mechanical solutions
– Flexible component arrangement (only rigid arrangements are possible with mechanical systems)
– Simple installation and commissioning
– No specialist hydraulic knowledge required
– For parametrization, a knowledge of electrical drive technology is sufficient
– With energy recovery, high system efficiency of up to 84 %: comparable with or higher than electromechanical systems

The entire system is considered and no longer just the individual components. Networked drives enable system management that uses energy as sparingly as possible.

Decentralized linear drives make the ideal contribution to meeting the requirements of the Energy Efficiency Strategy 2050. The AX pumps guarantee reliable operation with high performance and low power loss. 

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