Linear drive suppliersThe linear motor is very simple in principle, that is, the ordinary rotating motor is cut along the plane of its axis and developed into a plane. The side transformed from the stator of the original rotating electrical machine (ie the power feeding part) is called the primary; the side transformed from the original rotor (the non-feeding part) is called the secondary. The length of the primary (iron core and winding) is limited, called the actual length of the linear induction motor, which has a starting end and a terminal.
These two ends have end effect, which is only available in linear motors. If alternating current is applied to the primary coil, an alternating magnetic field that moves in a linear direction is generated between the primary and secondary conductors. Due to this alternating magnetic field, the induced current in the secondary guide plate interacts with the magnetic field, causing the secondary to generate an induced current, which interacts with the primary magnetic field to generate an electromagnetic force, thereby promoting the primary and secondary to move relative to each other.
Due to the simple transmission mechanism, the linear motor reduces the problem of interpolation lag, and the positioning accuracy, reproduction accuracy, absolute accuracy, and feedback control through position detection are higher than those of "rotary servo motors and ball screws", and are easy to implement. The positioning accuracy of the linear motor can reach 0.1μm.
"Rotary servo motor, ball screw" up to 2~5μm, and requires CNC-servo motor-backlash-free coupling-thrust bearing-cooling system-high-precision rolling guide-nut seat-table closed-loop transmission of the entire system The part should be lightweight and the grating precision should be high. In order to achieve higher stability, the "rotary servo motor and ball screw" should be driven by two axes. The linear motor is a high-heating component and needs to take strong cooling measures. To achieve the same purpose, the linear motor has to pay a higher price.
In terms of speed, the linear motor has considerable advantages. The speed of the linear motor reaches 300m/min and the acceleration reaches 10g; the speed of the ball screw is 120m/min and the acceleration is 1.5g. In terms of speed and acceleration, the linear motor has considerable advantages, and the speed of the linear motor will be further improved after successfully solving the heating problem, while the "rotary servo motor, ball screw" is limited in speed. Raise more.
The biggest difference between the direct drive of the linear motor and the transmission of the rotary motor in the feed system of the machine tool is that all intermediate transmission links from the motor to the worktable are cancelled. This transmission method is called "direct drive", commonly known as "linear drive", also known as "zero drive". This "zero transmission" method brings performance indicators and advantages that the original rotary motor drive method cannot achieve, but also brings new contradictions and problems.
With the development of direct drive technology, the comparison of linear motor and traditional "rotary servo motor, ball screw" drive mode has attracted the attention of the industry. Compared with rotary motors, linear motors have no rotary motion and are not affected by centrifugal force. Therefore, the speed of the linear motor can be very high, and the speed regulation is convenient, which is suitable for high-speed occasions.
In terms of life, the linear motor will not be worn due to the high-speed reciprocating motion of the mover due to the installation gap between the moving parts and the fixed parts. It is suitable for high-precision occasions. The ball screw cannot guarantee the accuracy in high-speed reciprocating motion. Due to high-speed friction, it will cause the wear of the screw nut, which will affect the accuracy requirements of the movement and cannot meet the needs of high precision.
The linear motion of the linear motor is adopted, and the motion mechanism has been successfully used in the computer-controlled precision turning and grinding of workpieces with special-shaped sections due to its fast response and high precision. Compared with the traditional method of machining special-shaped inner and outer circle contours by using "die", it has the characteristics of flexible programming modification and high machining accuracy, which is very suitable for the machining of multi-variety and small-batch products.