motor housing (3)

Small and medium batch prototype - The motor shell 3D printing prototypes

Motor housing generally refers to the external housing of all electrical and motor equipment. The motor shell is the protection device of the motor, which is made of silicon steel sheet and other materials by stamping and drawing process. In addition, the surface of the anti-rust and spraying process can protect the internal equipment of the motor. Main functions: dustproof, noise-proof, waterproof.

According to the material: the shell can be divided into metal shell, plastic shell, etc.

According to the use of: generator housing, starter housing, other digital products motor housing

Currently, with the support of national energy-saving and emission reduction policies, the new energy electric vehicle industry has been developing rapidly, and the development of traditional fuel vehicles to electric vehicles has been an inevitable trend. Permanent magnet synchronous motor has been widely used in the drive system of new energy electric vehicles because of its high power density, high efficiency, high reliability and safety. Usually, new energy electric vehicle motor operating environment temperature is high (usually higher than 70 ℃), but also requires the drive motor must have a strong overload capacity, dynamic response capability, which will bring the motor temperature rise problem. Therefore, it is very important to design a reasonable drive motor cooling system to better solve the temperature rise problem of the motor during the operation of new energy electric vehicles and to ensure the reliability of the drive motor.
During the operation of the permanent magnet synchronous motor, the heat generated by the copper loss of the motor winding and the iron loss of the stator core and rotor core is transferred inside the motor as shown in Figure 1. After analysis, most of the heat generated by losses inside the motor is transferred to the outside of the casing through heat conduction, following the transfer route of stator winding → stator core → cooling medium, and finally through the cooling medium. In addition, there is a very small portion of heat radiated from the housing shell to the surrounding air medium by means of thermal radiation, which accounts for a small proportion of heat and contributes less to the heat dissipation of the motor. Thus, how to solve the heat transfer from the stator winding → cooling medium becomes the key to solve the motor temperature rise problem.
The cooling medium flows in from the water inlet at the bottom of the casing, spirals up 4 times in the casing, and then flows out of the casing from the water outlet on the right side of the casing, completing a cycle of the cooling medium in the casing. Cooling channel structure design, taking into account the pressure of the hydraulic pump and cooling medium along the loss of resistance, in the spiral channel corner design transition rounded as large as possible, so as to reduce the cooling medium in the process of circulation along the resistance, but also in the production of casting process to ensure that the metal liquid smoothly fill the cavity, to avoid the formation of the cooling sprue volume gas, slag and other casting defects. The spiral cooling channel cross-section design is based on rectangular cross-section, assuming a uniform spiral waterway cross-section, and under the neglect of local head loss, Fluent is used to extract the waterway structure model and summarize the approximate relationship between the resistance along the spiral waterway and the parameters of the rectangular cross-section, where: Qfin is the coolant inlet flow rate, Ls, c, n, H, L denote the dimensions related to the spiral waterway structure with rectangular cross-section: axial length, bulkhead width, number of channels, channel cross-section width, and total flow length. It can be seen that the design of the spiral waterway structure has an important influence on the overall heat dissipation capacity of the PM motor and the selection of the cooling pump at the vehicle end for a certain inlet flow rate Qfin.