A potential problem in the design of tubular linear motor is that when the stroke increases, because the motor is completely cylindrical and moves up and down along the magnetic bar, the only supporting points are at both ends. It is always limited to ensure that the radial deviation of the magnetic rod does not cause the length of the magnet to contact the thrust coil. U-groove linear motor has two parallel magnetic tracks between metal plates, both of which face the coil mover. The mover is supported between two magnetic tracks by a guide rail system. The rotor is non-steel, that is to say, there is no attraction and interference between the magnetic track and the thrust coil. Non-steel coil assembly has small inertia and allows very high acceleration. The coil is generally three-phase and brushless commutation. Air cooling can be used to cool the motor to improve its performance. There is also a water cooling method. This design can reduce the leakage of magnetic flux because the magnets are installed face to face in the U-shaped guide groove. This design also minimizes the damage caused by strong magnetic attraction.
The magnetic track of this design allows combination to increase the stroke length, which is limited by the operable length of the cable management system, the length of the encoder and the ability of the large and flat structure of mechanical construction. There are three types of flat linear motors (all brushless): slotless coreless, slotless coreless and slotted coreless. The choice should be based on the understanding of the application requirements.
Slotless coreless flat motor is a series of coils mounted on aluminum plate. Because FOCER has no iron core, the motor has no pull-in effect (the same as the U-slot motor). This design helps to extend the life of bearings in some applications. The mover can be installed from above or from the side to suit most applications. This kind of motor is very suitable for applications that need stable control speed. Such as scanning applications, but the flat track design produces the lowest thrust output. Generally speaking, a flat magnetic track has high magnetic leakage. Therefore, care must be taken to prevent the operator from being hurt by the magnetic attraction between them and other sucked substances.
Slotless core: Slotless core flat motor is similar in structure to slotless core motor. Except that the iron core is first installed on the steel laminated structure and then installed on the aluminum back plate, the iron laminated structure is used to guide the magnetic field and increase the thrust. The suction between the magnetic track and the rotor is directly proportional to the thrust generated by the motor, and the laminated structure causes the joint to be stressed. Care must be taken when installing the rotor on the magnetic track to avoid injury caused by the suction between them. The slotless core motor has greater thrust than the slotless core motor.
Slotted iron core: This type of linear motor, the iron core coil is put into the steel structure to produce the iron core coil unit. The iron core effectively enhances the magnetic field generated by the thrust output of the motor through the focusing coil. The strong attraction between the iron core armature and the magnetic track can be used as the preload of the air bearing system in advance. These forces will increase the wear of bearings, and the phase difference of magnets can reduce the joint force.