Electric cylinder uses screw drive transmission to control motion, and the screw drive transmission is composed of nut and screw drive, ball screw drive, and planetary roller screw drive. The nut and screw drive transmission is gradually being replaced due to its high friction and low transmission power. The ball screw drive is now commonly used as a transmission component in electric cylinders, which can convert rotational motion into linear motion or convert torque into axial repeated force. It also needs to have the characteristics of high precision reversibility and high power. Many ball screw pairs have rolling motion between the screw shaft and the screw nut, and the electric cylinder with ball screw drive can have higher motion power. We also have products including compact electric cylinder.
The basic principle of planetary roller screw drive is similar to the above, but it has a larger load-bearing capacity in harsh environments and can work continuously for millions of hours. The planetary roller screw can operate continuously for a long time, and its unique feature lies in the design of the load transmission organization: multiple threaded rollers are dispersed in a planetary shape around the main screw, converting the rotary motion of the motor into linear motion of the main screw. The difference between ball screw drive and planetary roller screw drive is that the former has smaller volume and higher load capacity under the same load requirements, while the latter has larger contact area for load transfer, greater load-bearing capacity and higher mechanical stability.
The three control modes of the servo motor for a servo electric cylinder are speed control, torque control, and orientation control. The first two are controlled by analog quantity, while the latter is controlled by pulse generation. The specific control method should be selected according to the customer's requirements and the motion functions to be satisfied. For your information, we have electric cylinders for sale, at a solid price.
The torque control method of servo press cylinder is to set the output torque of the motor shaft to the outside by external analog input or direct address assignment. The size of torque is set by changing the analog input. In addition, the torque control is accomplished by changing the numerical value of the corresponding address through communication methods.
The orientation control of servo motor is generally recognized by the frequency of external input pulses to determine the speed of rotation, the number of pulses to recognize the position of rotation, or by assigning values to speed and displacement through communication methods. This method can strictly control the speed and orientation, so it is mostly used in positioning devices.
Electric cylinders can control the rotation speed by analog input or pulse frequency. When the outer control of the upper control device is in the speed mode, it can perform positioning, but it needs to use the orientation signal of the servo cylinder motor for calculation. The orientation mode also supports direct load external ring detection orientation signal, while the encoder at the motor shaft end can only detect the motor speed. The orientation signal is provided by the inspection device, reducing the error in the central transmission process and increasing the positioning accuracy of the whole servo system.