Listen to the experts how to say Tongmao linear motor, as we all know, equipment manufacturing industry, is the country's top priority, however, in the equipment manufacturing industry, in addition to CNC machine tools, few people know the linear motor is one thing, some people say that in the next 10 Years, even in less time, the linear motor direct drive will replace the traditional machine tool structure.
The history of the linear motor can be traced back to the last century, August 29, 1831, when Faraday, the father of British electricity, discovered the phenomenon of electromagnetic induction. Later, this electromagnetic induction became the basic principle of various types of motors and generators. Linearity The motor also takes advantage of this basic principle.
However, unlike other rotary motors, linear motors are not accepted by the industry until they are invented and are widely used. And by the front desk for commercial applications Linear induction motor, was invented by British electrical engineer Professor Eric Laithwaite in the 1970s, and it is only used to drive the shuttle in high-speed looms.
In recent years, due to the significant advantages of the linear motor direct drive technology, it has moved into precision motion control: such as integrated circuit manufacturing, wafer processing, precision and ultra-precision machining, aerospace and military equipment manufacturing and control.
The principle of a linear motor is the same as that of a rotary motor. Conceptually, a rotary motor can be deployed along its radial direction and lengthened according to the movement requirements, that is, a linear motor. The stator corresponds to the primary of the linear motor and the rotor corresponds to the secondary of the linear motor. When the primary phase in the three-phase sinusoidal current, the air gap between the secondary will produce a magnetic field, because the magnetic field is a translational, not rotating, it is called the traveling wave magnetic field, magnetic field and traveling wave Under the action of the class, electromagnetic thrust is generated, so that the secondary produces a linear motion. This linear motion can directly drive the table, simple structure, fewer transmission links, does not require the traditional rotary motor by the screw to convert, there is no transmission gap (including backlash), so the accuracy is called "direct Transmission "," no gap transmission "or" zero transmission ", but also has the characteristics of high-speed high-speed, unlimited travel.
As the linear motor is a direct conversion of electrical energy into a straight line of mechanical movement, and directly connected with the load, it has high speed and high acceleration characteristics. Linear motors today can achieve speeds of up to 5 m / s and high accelerations of up to 5 g in actual operation. In theory, the motor can reach 20g acceleration and 40m / s speed, but other mechanical structures such as rails and drag chains have limited the motor characteristics. Specific advantages are:
In terms of speed, the greater speed of the linear motor is limited only by the drive voltage and the controller. The speed of a linear motor is usually 3 m / s at a resolution of 1 micron and 5 m / s or more at a resolution of 10 microns.
Linear motor drive accuracy, resolution and repeatability depend on the feedback device. With a wide range of linear feedback devices, resolution and accuracy are primarily limited by the bandwidth of the control system. One of its advantages is that at high frequencies: the linear frequency response of a linear motor drive is 100 times more linear than conventional mechanical transmissions, resulting in faster accelerations that increase productivity in industrial applications. Second, the stiffness is good: because there is no mechanical transmission, the increase in stiffness can be increased by adjusting the gain and current of the drive, which is much better than the ball screw driven device. Of course it is limited by the peak thrust of the motor, the driver's higher current, and the resolution of the feedback device. Third, zero clearance: straight through the rail support linear motion, the middle of no other mechanical transmission components, so there is no gap. The currently widely used ball screw and other linear motion structure, there are gaps that can not be solved. Fourth, simple maintenance: Because the linear motor primary and secondary parts have no contact, so there is no wear and tear.
This article originates from Kunshan Tongmao Electronics Co., Ltd. (
www.tmmotion.com) original company, please indicate the source.
Linear motor