Art -Linear Actuators (2)

Linear Actuators

Intellidrives provide a wide range of linear motors for instance; linear stepping motor, liner servo motor, linear actuators, air bearings and rotary tables. Some motors can be equipped with linear encoders. DC electric linear actuators can be used in any application that requires the moving or lifting of loads. They are also known as linear motors. Electric actuators or linear actuators are also called hydraulic actuators, geared actuators, servo actuators and electric rams. Linear actuators are devices that can develop force and motion from an available energy source in a typically linear manner and not in a rotational manner as with electric motors.

There are diverse types of linear actuators and a good example is the mechanical actuator. linear actuators of this type are used to convert rotary motion from a control knob into linear displacement. This is accomplished via gears and screws attached to the knob. A good example of a mechanical actuator is a car jack or jackscrew. Linear actuators of the mechanical category are used in optics and lasers to manipulate positions of linear stages, mirror mounts, goniometers and rotary stages. Index marks control knobs to get accurate and repeatable positioning. The advantages of mechanical linear actuators is that they are cheap, repeatable and self contained. No power source is required and they have an identical behavior both when retracting and extending. These linear actuators are however not automated and are only operated manually.

Hydraulic linear actuators work with a hollow cylinder with a piston inserted into it. Both sides of the piston are pressurized so as to achieve controlled precise displacement in the piston and its entity as it occurs in linear actuators. Its design is based on the principle of the hydraulics, where the hydraulic pump controls the device. linear actuators of the hydraulic type accept extremely intense force it can leak and require position feedback for repeatability. Moreover, most often than not the hydraulic pump on these linear actuators is found externally.

Electro-mechanical linear actuators differ from mechanical actuators in that the control knob is replaced by an electric motor. As such Rotary motion of the motor gets converted into linear displacement, which is then channeled into the linear actuator. Different companies have different proprietary methods for linear actuators. The rotation of the electric motor in turn moves the lead screw. A lead nut with helical threads is threaded into the lead screw. The nut is made in a design that prevents it from rotating in tandem with the lead screw. Current linear actuators are built specifically for high speed or high force conversely; a compromise is struck between the two.

The basic principle behind the operation and the design of linear actuators is the inclined plane. Lead screw threads allow a small rotation force be utilized over long distances and accomplish a large load movement in a short distance. Some related parts of linear actuators such as the electric motor is laid down on a flat surface it essentially becomes a linear motor. Lead screws are not required to convert rotary motion into linear. Linear motors relatively have a low load capacity in comparison to other types of linear actuators.