Let's talk about side loads (also called overhung loads) for a minute. A side load is any load that is exerted perpendicular to the direction of a linear actuator's travel. A side load is any load that is not directly in line with the shaft of the actuator. Any force being applied to the shaft that is not directly in-line with the length of the shaft is considered a side load. There are a number of ways that side loading can occur. These include hanging a load from the actuator rod, incorrectly mounting the actuator or poorly implementing the actuator into a product or project.
Actuator's Intended Use
Linear actuators are intended to be loaded in-line with the device. When moving in or out it should be pushing or pulling the load directly with minimal side load. We provide a figure for maximum side load because we know that nothing is perfect and there will always be some amount of side load on the device. Just understand that side loading is hard on a rod actuator and even a small amount can reduce the life of the unit.
How Side Loading Affects Actuators
There are a few different ways. First, side loading increases internal friction. This causes the motor to work harder and can reduce the motor's life. Second, excessive loads perpendicular to the device can prematurely wear out the drive nut and/or lead screw. Third, loads above the rated figure could result in structural failure of the device.
In order to ensure that you're not overloading your device, always check the datasheet. Actuonix provides a figure for the maximum allowable side load at full extension in newtons. This makes it easy for you to figure out if you're exceeding that load or not.
Alternatives To Side Loading
If your project requires a significant side load, you have a few options.
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Redesign your mechanism to reduce side load.
Changing the amount of side load required from your actuator may just mean a minor adjustment to the design of your project. If you can not make such an adjustment, consider one of the next two options.
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Use a linear slide rail.
Linear slide rails are simple to use and reasonably inexpensive. To use a slide rail you need to mount the rail to something that is permanently fixed in position. You then mount the moving mechanism that is causing the side load to the sliding block on the rail. Last, you connect the actuator to drive the slide block, and your load, along the rail. The slide rail can handle much more side load than the actuator and doing this you will prevent overhung load failure of your actuator.
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Use a track actuator.
A track actuator is similar in operation to a standard rod actuator in that it uses a lead screw and drive nut. The key difference is rather than extending a shaft in and out, the body of the actuator itself is longer and a mounting block slides in and out with the load attached. A track actuator is convenient because it offers the functionality of an actuator and a slide rail, but keeps your design simple as it's one device instead of two. This also helps keep your costs down.
Repeated Actuator Failure
If you're experiencing repeated equipment failure or shorter than expected actuator life, check the side load and make sure it's in spec. You may be experiencing overhung load failure. Being over the manufacturer’s recommended side load figure can reduce the life of your device considerably.
If you have any questions about how to support a side load, or the capabilities of the device you're using, give Actuonix a call. We can help you with the product information you need before you load your actuator.
If you have any questions about our products or how to integrate them into your project, give us a shout, we're always happy to help.
Explore Actuonix Actuators Today
We hope this article has provided useful insights into managing side loads and actuator performance. To find out more about our actuators and explore our full range of products, visit our actuators by model page. As a leading manufacturer and innovator in the micro motion marketplace, Actuonix services companies big and small in a number of industries including aerospace, medical, robotics, and more. Get in touch with us today to submit an order or to submit an inquiry.