Second, the structural characteristics of the axial magnetic field motor
1. The disadvantages of axial magnetic field motors
The magnetic field of the axial magnetic field motor is axial, and the stator and rotor are placed in equal position in the motor. Both the stator and the rotor are disc-shaped, so they are also called disc motors. The stator core is generally formed by double-sided insulated cold-rolled silicon steel sheet strips. On the silicon steel strip, a groove of exactly the same size is punched out at a certain distance, under the condition that the corresponding slots are aligned one by one. The stator core with the lower wire groove on the end face is formed by winding. The stator winding effective conductors are radially distributed in space. The rotor is a high magnetic energy permanent magnet, which is fixed on the disc core. The core machining of the axial motor stator is the key to motor manufacturing.
In actual production, due to various deficiencies in the blanking process and the unique structure of the stator core itself, the thickness of the silicon steel sheet is extremely thin, 0.5 to 1.0 mm, and thus the following problems occur more or less in the automatic forming of the circumference: The silicon steel sheets on both sides of the aligned slots are "bell-shaped" open; in the winding forming, in the case of insufficient rigidity of the winding machine, compaction is often caused; and the pre-perforated grooves are difficult to align. problem.
2. Armature core based on soft magnetic composite material (sMc)
Due to the magnetic circuit geometry, the axial magnetic field motor is difficult to manufacture the core by the lamination technology. The two methods can solve the problem of the laminated core: one is to use a solid body for processing or to use a printed core; the other is to use a coreless or Approximate magnetic circuit structure without iron core. The feasibility of these two methods is based on the acquisition of new materials: three-dimensional shaping by soft magnetic powder composites or directly through the pressing process to manufacture the stator core; high-performance hydromagnets and good thermal properties Plastic materials with mechanical properties to reduce or eliminate the use of ferromagnetic materials. At present, plastic materials are rarely used as structural members of motors due to cost. It is only used in plastic axial field motors that require light weight and high efficiency.
In order to overcome the difficulty in manufacturing laminated cores, the stator core is machined from SMC solid cylinders. A lot of slots are opened in the solid cylinder to secure the armature winding
group. The winding is fabricated into a concentrated winding which shortens the end connection of the phase winding and reduces the winding resistance, thereby reducing copper losses.
