With the expansion of the new energy market, more and more manufacturers are engaged in the research and development of motors. Although many manufacturers have been committed to this, we still haven’t seen large-scale equipment. What are the differences between hub motor and traditional motor, and what are their advantages and disadvantages? Today we will analyze them in detail.
1. Is the principle of the wheel motor the same as that of the traditional motor?
Take the hub motor as an example, it is mainly composed of stator, rotor and additional parts. The stator core is generally made of silicon steel sheet with insulation layer, which is used to place the stator winding. The stator windings are distributed on the center of the circle at the same angle, that is, 120 degrees. The coils on the winding are wound according to certain rules, and the current flows through the stator winding to generate a rotating magnetic field. At this time, the rotating magnetic field and the rotor conductor have relative cutting motion. According to the principle of electromagnetic induction, the rotor conductor generates induced electromotive force and induced current. The rotor conductor is affected by electromagnetic force in the magnetic field, forming electromagnetic torque to drive the rotor to rotate. Generally speaking, it is the process of converting the electrical energy of current into mechanical energy. I believe that many people played 4WD when they were children, and the motor driving 4WD is a small motor, except that the two magnets inside are permanent magnets, and AC motors need electricity to generate magnetic fields. Compared with internal combustion engines, motors are actually simpler and easier to control.
In fact, the principle of the wheel motor is no different from that of the traditional motor, except that it is more compact in structure, which means that there are fewer coils and the magnetic field is not as strong as that of the motor arranged in the traditional position, so the output power is relatively small. In addition, there are two types of in wheel motor: internal rotating motor and external rotating motor. The rotor of the external rotating motor is located inside the stator, just like the traditional motor. The rotor of the external rotating motor is located outside the stator and rotates around the stator. The hub motor integrates the power device, transmission device and braking device into the hub, so the mechanical part of the electric vehicle is greatly simplified.
2. What are the advantages and disadvantages of in wheel motor compared with traditional motor?
As mentioned above, due to the limited diameter of the wheel hub and the width of the tire, the maximum volume of the wheel hub motor is not as large as that of the traditional motor, and the output power is difficult to meet the standard. Therefore, at present, many wheel hub motors are only used in two wheel riding electric vehicles. Compared with the traditional motor, the wheel motor actually has many very significant advantages. First of all, this design has no transmission loss, because there is no transmission rod from the engine to the wheel, so the efficiency is very high. In addition, the hub motor can realize differential steering similar to tracked vehicles by reversing the different rotational speeds of the left and right wheels, greatly reducing the turning radius of the vehicle. In special cases, it can almost achieve in-situ steering, which is often called tank turning. In terms of loading space, in wheel motor vehicles also have advantages, and they can have large suitcases at the front and rear.
There are so many advantages. Why is it difficult to see in reality that in addition to the power factor, there is also the cost that restricts development. Because the wheel hub also needs to integrate the brake system, the integration difficulty is higher than that of the traditional motor. And the heat dissipation of the brake system is also a very important part. Although the motor does not need too much air to dissipate heat, it will occupy most of the volume, making it more difficult to dissipate heat, and there are hidden dangers in brake safety.
Secondly, the service life of the motor is also more expensive than that of the traditional motor placed in the middle of the vehicle. The motor in the cabin will have multiple protective layers, and will not be exposed to the wind and the sun. The stones and dust on the road will not affect the motor. Because the wheel motor is exposed to the outside, it has a short service life and often needs maintenance. These are the problems that need to be solved urgently
