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Electric actuators oust hydraulics from vehicles

Edited by the Engineeringtalk editorial team Apr 13, 2004

Reducing costs, improving ergonomics and reducing operator fatigue have long been objectives for vehicle designers, particularly in the construction industry.

Reducing costs, improving ergonomics and reducing operator fatigue have long been objectives for vehicle designers, particularly in the construction industry.

The rapid increase in the use of electromechanical actuation in vehicle design is as a direct result of these and other market drivers.

Today, Danaher Motion's range of electromechanical actuation products is opening up new possibilities for automation that were perhaps not previously thought practical.

Automation of many manual operations has often been considered impractical, particularly when considering hydraulic actuation as the solution.

The resulting increase in the size of the hydraulic system can add cost and complexity to a prohibitive level.

In addition, the need for many of these tasks to be performed without the engine running has supported the decision to keep things manual.

Use of electromechanical actuators can overcome many of the associated difficulties of applying hydraulic solutions - they are clean, efficient, easy to install and only require electrical power to drive and position.

Concerns regarding potential contamination from hydraulic fluid are eliminated, as well as enabling a reduction in the size of the hydraulic system.

The facility to drive an actuator electrically, without the engines running means that many new applications are now possible.

Designers can also give the operator much more controllability, given that only an electrical signal is needed to drive and position an actuator, positional feedback can be integrated and electrical cables are much easier to manage than hoses.

The possibilities and realities of vehicle automation have been significantly widened as a result of Danaher Motion's product developments.

In most cases, an actuator consists of an electric motor and gearing, driving a ball screw or lead screw and a lift-arm, packaged into a compact form than can be easily installed in just about any space.

They are typically mounted just as a hydraulic cylinder would be, using clevis or trunnion mountings, and are very similar in terms of size.

Additional features such as positional feedback can also be incorporated into the package.

Use of a ball screw to convert the rotary motion to linear motion results in a device that is extremely efficient with very low wear and a long and predictable life.

When considering whether an application is suitable for electrical actuation, some factors need to be examined.

First, engineering fundamentals such as load, speed, stroke length and electrical power are considered, then factors such as robustness, sealing and duty cycle need to be taken into account.

Applications in the construction industry demand robustness to another order of magnitude.

Reliability and resistance to vibration and shock loads are essential in most cases, requiring the actuator to be designed and manufactured specifically to handle these demanding factors.

In many cases designers need flexibility in terms of the design of the actuator, features such as mounting configuration, electrical connection, position feedback are often customised for the requirement of the application.

With the wide variety of applications in the construction industry Danaher Motion has produced a broad standard product range with highly flexible design capability.

Often a large degree of customisation is required to meet the unique criteria of each application.

Design modifications such as special electrical connections and mounting methods as well as dimensional and key performance changes are necessary in many cases to provide the OEM with a design that meets his exact requirements.

There is undoubtedly a strong trend towards increased application of electromechanical automation, the advantages of oil free operation, eliminating contamination, as well as reduced energy consumption are opening up new possibilities for the construction vehicle designer, and allowing more automated, ergonomic, cleaner and efficient equipment for the consumer.