The motion control industry has gone through numerous changes over the decades. From its humble beginning to the present Industry 4.0 trend, novel technologies have taken over outdated ones and led to higher productivity and optimization. One of the most impactful of these transformations is the shift from electrohydraulic to electromechanical linear actuators. A huge chunk of industrialists is replacing their hydraulic actuators with electric industrial linear actuator devices, like the lawn care market.
In this issue, we will discuss why you should switch over to electromechanical actuators and strengthen our argument with a case study from one of our clients. This blog offers interesting information regarding the application, mounting, and load-bearing, so make sure you read to the end!
Why Electric Over Hydraulic?
There is a multitude of solid reasons for people preferring electric over hydraulic linear actuator products. While the electric vs hydraulic actuator debate is multi-faceted, we have broken it down into comprehensible segments for your convenience:
Precision Control & High Speed
The elite speed and control dynamics of electric linear actuators are the biggest reason for them being better. Hydraulic actuators are operated via a fluid, which is not as easily controlled as an electric motor owing to its compressibility and viscosity. When initiating motion or changing directions, this fluid induces a lag in the system that is sometimes detrimental to the application. On the other hand, the electrically powered, often logic-controlled, motor in an electromechanical actuator has a near-instantaneous response to input signals. This is well-suited to modern applications and certainly a reason for shifting over to electric.
From a business point-of-view, there is a clear advantage in choosing electric over hydraulic cylinders. Electric linear actuators are less costly to purchase, setup, and maintenance in comparison with hydraulic actuators. This benefit is so lucrative that many engineers opt for electric systems purely because of the higher ROI and quicker profits.
Keeping something in perfect condition is never an easy job, especially when it comes to industrial linear actuators. Hydraulic actuators can malfunction in a variety of different ways such as fluid leakages, broken seals, mechanical failures, etc. Electric linear actuators are quite well-designed on the contrary. Their drivers and transmission units are rugged, their bodies are sturdy and adequately sealed, and they are precision-engineered for industrial applications. These make them safer to use and less prone to damage.
Our PA-13 is a great hydraulic replacement thanks to its high force ratings and stroke range!
Hydraulic to Electric Actuator: A Case Study
Instead of listing the possible cons of swapping to electric linear actuators, we have a better idea for dealing with them. Rather than just enlisting them and leaving you double-minded, we thought it is best to show you how these disadvantages can be dealt with.
One of our customers decided to upgrade their hydraulically actuated industrial unit with an electric linear actuator and contracted our engineers for the project. They were faced with numerous problems that needed to be addressed which were handled and successfully delivered a reliable product to them.
Figure 1: Customer’s Application
Our team opted for the PA-13 linear actuator as a replacement owing to its high power/force rating and stroke range. There were two major drawbacks to this hydraulic to electric conversion:
- Space: Electric actuators are notably larger in size compared to their hydraulic counterparts with the same power ratings. This meant that the PA-13 took up more space in the machine than the hydraulic one, limited maneuverability.
- High Loads: Hydraulic actuators have the edge when it comes to producing and withstanding forces. Hence, the electric replacement we proposed was unable to bear the stresses being generated by the machine and required some customized reinforcement for proper functioning.
Progressive Actuators accepted this challenge and executed this change-over with minimal re-designing of the machine. Our approach is summarized below.
The main problem our engineers were faced with was the limited space available for the electric linear actuator. We had to ensure the same degree of freedom, but in a lesser space.
The solution we came up with was quite innovative and very practical. An actuator’s range of motion is restricted by its mounting configuration. We realized that altering its mounting position would do the job. Figure 1 shows that the actuator needs to be able to rotate around a certain point, which is also its mounting position.
While linear actuators are normally mounted at their ends when there is a pivot involved, for example, in a door closer, we decided to shift the pivot to the middle of the shaft to liberate it from motion restrictions. This required special circular trunnion mounts to be designed and welded onto the shaft’s housing. These mounts are as tough as end-mounts and serve as excellent pivots. This simple alteration allowed the actuator to rotate as freely as the hydraulic actuator without compromising on its rotational movements.
The trunnion mounts did the job of dealing with the tight space, but they were not enough to protect the actuator against high loading. For this, we designed a special bracket that was bolted to the end of the actuator for additional support and stress-bearing.
The inclusion of this bracket in the design made the base rigid and resistant towards buckling and bending, the two most dreaded failures in the linear actuator industry.
Figure 2: Our Design
Figure 2 shows our final design. We would like to highlight the simplicity of this product and how a couple of minor adjustments solved a big problem. Electric linear actuators surely have their downsides, but they can be overcome with some ingenuity and engineering.
How to Change Over?
We hope we have highlighted why electric is preferred over hydraulic actuators and the key benefits that they offer. They have an upper hand in terms of actuation quality and price, and their disadvantages can be dealt with easily.
Progressive Actuators is a leader in the electric linear actuator market. If you are looking to reap the benefits of electromechanical linear actuators, take a look at our top of the line products and contact our experts for technical assistance. We are glad to be of service!