What Is a Robo Cylinder?
A robo cylinder is an electrically operated cylinder.
Cylinders include air cylinders that use compressed air and hydraulic cylinders that use oil pressure. Both air and hydraulic cylinders are driven by fluid supplied from one or both sides. In contrast, robo cylinders are powered by electricity.
Robo cylinders are designed for linear motion and operate on a single axis. Unlike air cylinders, which typically position at two or three points, robo cylinders can freely position within their stroke range.
Usage of Robo Cylinders
Robo cylinders find use in various applications, such as processing, assembly, conveyance, and packaging equipment. They offer significant energy savings over air cylinders, which often lose efficiency due to piping resistance. Robo cylinders consume approximately one-tenth the power of air cylinders.
Additional benefits include reduced shock on stopping, shorter tact times, simpler design and manufacturing, and versatility with different products. The term “Robo Cylinder” specifically refers to the electric actuators developed by IAI, designed to replace air cylinders effectively.
IAI has also introduced the Elecylinder, focusing on two-point movements and targeting the air cylinder market.
Principle of Robo Cylinder
A robo cylinder mainly comprises a ball screw, a linear guide, and an AC servo motor, making it compact and suitable for handling lightweight materials.
Larger and more rigid single-axis robots are used for equipment dealing with heavy objects, in contrast to robo cylinders.
1. Ball Screw
Ball screws in robo cylinders convert rotational motion from a servomotor into linear motion. They are known for high power transmission and positioning accuracy.
2. Linear Guide
Linear guides support the linear motion of the ball screws. As ball screws are limited in their resistance to non-linear forces, linear guides ensure unimpeded linear movement.
3. AC Servo Motor
AC servo motors, the power source for robo cylinders, control rotation using an encoder. This control allows precise management of the ball screw’s linear movement, thus enabling adjustable driving distances for the robo cylinder.
How to Select a Robo Cylinder
Robo cylinders are broadly categorized into rod and slider types.
1. Rod Type
Rod-type cylinders extend and retract a rod, requiring larger installation space but are suitable for pushing operations. For radial load-bearing, a linear motion guide is necessary, or a guided type should be chosen.
For rod types, ensure the selected model can generate thrust exceeding the required thrust as the guide handles the moment load.
2. Slider Type
Slider-type cylinders integrate with a linear motion guide. The slider directly attaches to the moving object. In this type, select a model within the tolerance range of the integrated guide.
Determine the moment load on the slider based on the moving object’s center of gravity and weight, ensuring it doesn’t exceed the guide’s allowable moment load. Then, verify the payload at operating speed against the speed-carrying weight table, ensuring the object’s weight doesn’t surpass the payload. Note that payloads vary significantly between horizontal and vertical mountings.
Other Information on Robo Cylinder
Functions of Robo Cylinder
Robo cylinders are capable of position, positioning, and pushing operations, offering more sophistication than air cylinders.
1. Position Operation
In position operation, a “position” (stop position), along with speed and acceleration settings, are pre-registered with a host device like a PLC. The robo cylinder moves to the specified stop position upon receiving a position number from the host.
2. Positioning Operation
In positioning operation, travel, speed, and acceleration are directly specified by a host device. The robo cylinder operates according to these parameters.
3. Pushing Operation
In pushing operation, the robo cylinder exerts a preset push force, controlled by a host device after setting via a teaching pendant or PC software.