Air bearings offer numerous advantages over mechanical bearings such as profiled linear guides and crossed roller slides. But they are still considered by many designers and engineers to be a high-cost solution, primarily for niche applications that require extreme precision. However, their benefits include more than just high precision, and cost is being driven down […]
Applications
What are V-belt pitch length and datum length?
The length of a V-belt can be specified in several ways, including outside length, effective length, and pitch (or datum) length. Outside length is measured around the belt’s outer diameter with no tension, but is only an approximation and is not useful for sizing or selection. Effective length is measured at the effective outside diameter […]
Maximizing performance of precision motion stages in industrial applications
Motion controller and drive features can address the natural behavior of motion stages that can otherwise degrade throughput and accuracy — including those arising from mechanical resonances, inertia mismatch, motor cogging, backlash, friction effects, and encoder signal distortion. By Jason Goerges and Boaz Kramer • ACS Motion Control Precision motion stages operate in industrial applications […]
Linear-actuator application example: New angle on wheelchair vehicle accessibility
Kneeling systems have become widespread on custom wheelchair-accessible vehicles from BraunAbility and other accessible-vehicle converters. Here linear actuators lower vehicles’ rear suspension to reduce the incline angle of wheelchair ramps for easier access. Because the actuators typically mount under the vehicle chassis, they must be rugged. “Our vehicles typically kneel 2.5 to 3 in. We […]
Synchronous belt failures: Six ways they can occur
Synchronous belts can transmit high torque without the potential for slip, due to positive engagement between the teeth of the belt and the grooves of the pulley. But the performance of synchronous belt drive systems can be affected by installation errors, unexpected application conditions, or the use of components that aren’t suitable for the operating […]
Pulley balancing for belt drive systems: Is it always necessary?
As a pulley rotates, centrifugal forces act on the pulley, and if its mass is not evenly distributed around the axis of rotation – that is, if it is unbalanced – these centrifugal forces will also be unbalanced and cause the pulley to vibrate. (Uneven mass distribution can be due to imperfections in machining or […]
What is ratcheting in synchronous belt drives?
Synchronous belts (also referred to as toothed, cogged, timing, or high torque belts) use profiled teeth that mesh with a pulley or sprocket to deliver power transmission – most notably for applications that require high torque. Where V-belts rely on friction between the sidewalls of the belt and the sides of the pulley to transmit […]
High-speed linear actuators: What qualifies them as high speed?
Like many terms used in the linear motion industry, such as “heavy duty,” “miniature,” and “corrosion-resistant,” to name a few, there is no industry standard that specifies what constitutes a “high-speed” linear actuator. Nevertheless, there are some general guidelines that manufacturers follow when classifying and marketing their actuators as high speed. These guidelines are typically […]
Common applications for linear rails
Linear rails are linear assemblies that have twin parallel tracks containing load-supporting balls or rollers. The backbone of many industrial applications, they provide low-friction guidance and high stiffness for loads that can range from just a few grams to thousands of kilograms. Their variety of sizes, accuracy classes, and preloads make linear rails suitable for […]
Defining the compliance of electromechanical linear actuators
Modern motion controllers with built-in frequency analyzers allow direct identification of electromechanical actuators … under load … subject to real-word conditions. That in turn may help designers improve stiffness and actuator performance — even to the point of getting higher servo bandwidth. By Leonid Gannel, Ph.D. • Servo engineer • Jabil Shemer Motion Frequency analyzers […]