Principles and advantages and disadvantages of rodless cylinders
- The principle of rodless cylinder
The working principle of the rodless cylinder is the same as that of the ordinary cylinder, except that the external connection and sealing form are different. High requirements for environmental cleanliness.
There is a piston in the rodless cylinder, but without a piston rod, the piston is installed in the guide rail, the external load is connected to the piston, and the actuation depends on the air intake.
The magnetic coupling movement is realized by using the permanent magnet in the hollow piston rod to drive another magnet outside the piston rod. Because of its high speed and high load, the inner and outer magnetic rings are easy to disengage, so it is less used now. The size of its load mass needs to find the characteristic curve of its mass and speed. Now the mechanical type is used more.
Second, the classification of rodless cylinders
Rodless cylinders are divided into magnetic couple rodless cylinders and mechanical contact rodless cylinders. A rodless cylinder refers to a cylinder that uses a piston to directly or in a way to connect to the outside world, and make it follow the piston to achieve reciprocating motion. The biggest advantage of this cylinder is to save installation space.
(1) Magnetic coupling rodless cylinder:
The piston drives the moving body outside the cylinder to move synchronously through magnetic force. Its working principle: A set of high-strength magnetic permanent magnet rings are installed on the piston. The magnetic lines of force pass through the thin-walled cylinder and interact with another set of magnetic rings sleeved outside. Because the two sets of magnetic rings have opposite magnetic properties, they have strong attraction. When the piston is pushed by air pressure in the cylinder, under the action of magnetic force, the magnetic ring sleeve outside the cylinder is driven to move together. The thrust of the cylinder piston must match the suction of the magnetic ring.
(2) Mechanical contact rodless cylinder
A groove is opened in the axial direction of the cylinder tube, and the piston and Shangzhi move on the upper part of the groove. In order to prevent leakage and dustproof needs, stainless steel sealing tape and dustproof stainless steel tape are used to fix the cylinder heads at both ends at the opening. The piston frame passes through the groove to connect the piston and Shangzhi into one. The piston is connected with Shangzhi to drive the actuator fixed on Shangzhi to reciprocate.
Third, the characteristics of the rodless cylinder
- Compared with ordinary cylinders, the installation device can be reduced by 1/2 under the same stroke;
- No need to install anti-rotation machinery;
- Suitable for cylinder diameter 10-80mm, the maximum stroke can reach 41.5m;
- Speed 10m/s
Fourth, the disadvantages of rodless cylinders
- Poor sealing performance, prone to leakage. When using a three-position valve, the medium pressure type must be selected;
- The load force is small. In order to increase the load capacity, a guiding machine must be added.
The brand of rodless cylinder:
The rodless cylinders currently circulating in the market mainly include ORIGA rodless cylinders, Norgren rodless cylinders, FESTO rodless cylinders, SMC rodless cylinders, and Koganei.