Talking about Linear Motor
time£º2017/7/7 click£º6352
A linear motor is a transmission that converts electrical energy directly into linear motion mechanical energy without the need for any intermediate conversion mechanism. It can be seen as a rotating motor that is opened in a radial direction and developed into a plane. There are two forms of linear Motors, namely servo and stepping.
Imagine a motor, whether DC or AC, cutting and leveling along the diameter of its shaft to become a linear motor. According to the left-hand rule, it can be judged that the winding around the armature at this time is subject to electromagnetic force. F, Since the winding is fixed in the armature, the armature will move in a straight line under the action of electromagnetic force F. Obviously, whether it changes the magnetism of the magnetic pole or changes the polarity of the power added to the brush, it can change the direction of the electromagnetic force., That is to change the direction of the armature.
The advantage of linear Motors
Precision, precision, resolution and repeated positioning accuracy are all determined by the feedback system.
High speed, the speed of the linear motor depends on the voltage rectified by the controller and the controller itself. The speed of the general linear motor is 3 m/s, and its resolution is 1 micron. Some linear motors can reach 5 m/s.
Rapid response: In general, a linear motor system has a rapid response 100 times faster than a normal mechanical transmission, so its production efficiency is also higher.
Stiffness: Since the linear motor does not have a mechanical connection, stiffness depends only on the gain and current of the system.
Return gap: There is no return gap because there is no mechanical connection.
Easy to maintain: Today's linear motors do not have mechanical contact, so, there is no maintenance.
Shortcomings of linear Motors
Cost: Linear motors are very expensive due to the relatively small amount of linear motors and the price of permanent magnets. Since most linear motor designers install permanent magnets on guide rails, permanent magnets are very expensive, so long stroke linear motors are very expensive. However, with the popularity of linear motors and the increase in production, prices will come down in the near future. However, the feedback system of the linear motor should also be calculated into the cost, and the cost of encoders and rotating Transformers is not high from time to time because the length is not very long. However, linear Motors also require feedback systems. These feedback systems are much longer than encoders, so the price will be high. A 100 mm linear motor feedback system costs more than 500 dollars. Of course, the price will increase with length. However, with the emergence of new reflective encoders, the manufacturing cost will inevitably decrease.
The bandwidth of the controller will increase: Since there is no mechanical connection between the motor and the load, the servo controller's response, that is, the bandwidth, is fast. This puts a higher requirement on the linear encoder.
The size of the coil: Compared with the rotating motor, the force generated by the linear motor is not a compact force. For example, to produce a continuous force of 65N, Then the cross-section of the linear motor is about 50MM X 40MM. If it is compared with a ball bar with a cross-section of 10MM, the force it produces is not very large.
Heat: In most cases, the load is mounted directly on the slide. Any overheating will be transmitted directly to the load. If the load is sensitive to heat, then there must be cooling technology.
Today, the linear motor and its driving control system have become more and more mature in technology, and it has advantages that can not be compared with traditional transmission devices. In the past, problems such as small thrust, large size, high temperature, poor reliability, difficult installation, and difficult protection of linear motors that were feared in the past were no longer major problems with the improvement of motor manufacturing technology.
Linear motors are mainly used in three aspects:
First, it is applied to automatic control systems. There are many applications in this type of application.
The second is the drive motor as a long-term continuous operation.
Third, it is applied to devices that require a short time and a short distance to provide huge linear motion energy.
In recent years, linear motors have been studied, developed and applied in many parts of the world, making the application of linear Motors more and more extensive.
For more knowledge about linear Motors, welcome to Kunshan Tongmao Electronics Co., Ltd.. Official website www.tmemotion.com.
Linear motor