CN107947498A - A kind of motor stator and its manufacture method - Google Patents

Abstract

The invention relates to a motor stator and a manufacturing method thereof, wherein the manufacturing method includes the following steps: forming a stator inner core; making a pipeline mold surrounding the stator inner core with a soluble material; placing the stator inner core and the pipeline mold on In the cavity of the stator mold, the pipeline mold is located outside the inner core of the stator; under certain conditions, the liquid metal is introduced into the cavity between the inner wall of the stator mold and the outer wall of the inner core of the stator to form the outer core of the stator; after the liquid metal is solidified , take out the metal preparation and put it into the solution that can dissolve the pipeline mold, and form the pipeline mold into a heat dissipation channel. The stator manufactured by the invention can realize high-efficiency heat dissipation.

Description

A motor stator and its manufacturing method

technical field

The invention relates to a motor stator for an electric vehicle and a manufacturing method thereof.

Background technique

The electric motor is a key component of electric vehicles, which converts electrical energy into mechanical energy, providing rotational torque, which translates into linear motion of the vehicle. Like all mechanisms that convert one energy source to another, an electric motor generates heat during normal operation. When the current passes through the silicon steel or the permanent magnet assembly, part of the power is dissipated in the form of heat, which makes the motor heat up and the temperature rises. However, the working temperature of the motor must be limited within a certain range. Once it reaches the Curie temperature, the permanent magnet rotor will be irreversibly demagnetized, thereby losing the electromagnetic conversion capability, and the motor will also lose its function. Moreover, the greater the power of the motor, the more heat it generates and the higher the temperature of the motor. Therefore, accelerating heat dissipation and reducing the temperature rise of the motor have become the key means to improve the efficiency of the motor.

With the increasing power conversion requirements of modern electric vehicles, the cooling of electric motors has become the key to improving the efficiency of electric motors. More importantly, motor efficiency varies even among motors produced by the same manufacturer. Although this depends on the rated power of the motor and the number of motor poles, the efficiency of the motor is greatly controlled by the heat generated by the motor. Since motors are classified and priced according to their rated efficiency into standard, premium and high-end categories, higher efficiency motors are preferred in order to save on operating costs. Therefore, the industry needs not only motor design, but also improved motor efficiency through integrated manufacturing. It is generally believed that increasing the cooling rate of the motor can not only improve the efficiency of the motor, but also improve the operational reliability of the motor.

Normally, the high thermal energy in the motor will be automatically transferred to the low energy area without the need for external force to do work. Therefore, the heat generated during the operation of the motor can only be transferred to other parts of the motor through heat conduction, convection or radiation, or to the external environment. The cooling of the motor can generally be achieved in two different ways by reducing system heat generation or by increasing total heat dissipation. The use of high-quality materials such as high-grade silicon steel and optimized electrical/mechanical system design help reduce heat generation. Increasing the total heat dissipation is closely related to the manufacturing method. Mandatory direct spray cooling or enhanced cooling with liquid circulation are the most effective ways to increase total heat dissipation. In addition, the cooling of electric motors for electric vehicles tends to adopt direct cooling or use cooling channels to increase convective heat transfer capacity. More importantly, it is easy to implement in reality. Water and oil are two commonly used liquid media. Possible techniques include microchannel liquid cooling, spray cooling, and jet impingement direct cooling. As the power consumption level of electronic systems continues to increase, the technology of channel liquid cooling is more reliable and convenient, so it will become an inevitable trend in the future. On the other hand, the integrated manufacturing structure can significantly improve the heat exchange efficiency and increase the heat dissipation of the motor. Therefore, the manufacture of highly integrated structures is an effective way to improve the efficiency of motors.

Industrial electric motors typically have efficiencies between 70% and 80%. The motor efficiency is the difference between power consumption P and power dissipation PL divided by power consumption P, and can be expressed as η=(P-PL)/P. The power loss PL can be calculated from the temperature difference (ΔT) measured at the inlet and outlet of the liquid cooling jacket. The formula is PL=cfΔT, where c is the specific heat capacity of the liquid medium and f is the flow rate of the liquid medium. In practice, the flow is adjusted so that the motor does not exceed the temperature difference, ideally at the level of 5-10K.

In the manufacture of electric motors, the rotor, stator and container are the three key components. A rotor is a rotating electrical component whose shaft of rotation transmits mechanical power. The rotor typically contains conductors that carry currents that interact with the stator's magnetic field, creating a force that turns the shaft. The rotor is located inside the stator and is mounted on the motor shaft. The stator is the stationary part of the motor's electromagnetic circuit and usually consists of windings. The stator core is made of many thin silicon steels to achieve high magnetic permeability and low hysteresis. The rotor and stator must be strong and precision machined so that the stator is concentric with the rotor. The stator and rotor are assembled in the same container, which can be made of cast aluminum or cast iron. Unlike traditional air-cooled vane containers that are directly cast, cooling channels are currently mostly machined from castings with specific shapes. The main reason is that the traditional casting process cannot manufacture complex cooling channels. Especially when die casting is used, the strength of the general casting core is not strong enough. At the same time, when the processed casting container is assembled with the stator, there is a mechanical gap between the stator and the container for assembly operation. Since the heat generated in the rotor and stator is transferred to the environment through the container, the gap between the stator and the container is very unfavorable for heat transfer and heat dissipation.

The present invention is to solve the above-mentioned problems. For practitioners, existing manufacturing techniques for electric motors for electric vehicles have several inherent disadvantages. For example, the machining of cooling channels limits the complexity of its shape and distribution. Especially the machined cooling channels need to be sealed by welding. This manufacturing process is divided into many steps, thus not only increasing the difficulty of quality control, but also increasing the manufacturing cost. At the same time, the low integration of the structure of the motor results in poor heat dissipation. Therefore, increasing the integration of the structure can not only improve the cooling efficiency, but also reduce the manufacturing steps, thereby reducing the cost.

Contents of the invention

In order to solve the above-mentioned technical problems, the object of the present invention is to provide a motor stator for electric vehicles with better heat dissipation effect.

Technical scheme of the present invention is as follows:

A method for manufacturing a motor stator, characterized in that it comprises the following steps:

forming the stator core;

making a pipeline mold around the inner core of the stator from a soluble material;

Place the stator core and tube mold into the stator mold cavity, with the tube mold on the outside of the stator core;

Under certain conditions, liquid metal is introduced into the cavity between the inner wall of the stator mold and the outer wall of the stator inner core to form the stator outer core;

After the liquid metal is solidified, the metal preparation is taken out and placed in a solution that can dissolve the pipeline mold, so that the pipeline mold forms a heat dissipation channel.

Further, the inner core of the stator is formed by laminating multiple thin silicon steel sheets.

Further, the liquid metal is formed by one or more of copper alloy, aluminum alloy, magnesium alloy and zinc alloy.

Further, the certain condition is to introduce liquid metal under high pressure.

Further, the certain condition is to introduce liquid metal under vacuum.

A motor stator, characterized in that it comprises:

Stator inner core (11);

The stator outer core (12) is formed by casting liquid metal to the outside of the stator inner core (11);

And the heat dissipation pipeline (13) arranged in the stator outer core (12) is formed by making a pipeline mold before casting the stator outer core (12), and then dissolving the pipeline mold.

Further, the pipeline (13) includes a long channel (131) and a short channel (132), wherein the long channel (131) and the short channel (132) are connected end to end in an "S" shape, and the long channel (131 ) are evenly distributed inside the stator outer core (12) along the axial direction of the stator outer core (12), and the short channels (132) are evenly spaced around the stator outer core (12) outside the stator Core (12) two ends.

Further, the pipe (13) is a spiral pipe arranged inside the stator outer core (12).

Further, one end of the pipeline (13) is connected with a liquid inlet (133), and the other end is connected with a liquid outlet (134).

Further, the stator inner core (11) is formed by laminating multiple thin silicon steel sheets (111).

By means of the above solution, the present invention has at least the following advantages:

(1) By casting the stator outer core directly on the stator inner core, the gap between the stator inner core and the stator inner core is reduced;

(2) The soluble core is used to make the cooling channel inside the outer core of the stator, which can design the heat dissipation channel to have a larger heat dissipation space, increase the heat exchange area, and improve the heat dissipation capacity;

(3) The manufacturing method of the present invention is simple, can reduce manufacturing steps and save manufacturing cost.

The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly and implement it according to the contents of the description, the preferred embodiments of the present invention and accompanying drawings are described in detail below.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic structural view of a stator outer core according to an embodiment of the present invention;

Fig. 3 is a schematic structural view of a stator outer core according to another embodiment of the present invention;

Fig. 4 is the structural representation of thin silicon steel sheet of the present invention;

Fig. 5 is a schematic structural view of the inner core of the stator of the present invention.

In the figure: 10- motor stator; 11- stator inner core; 111- thin silicon steel sheet; 12- stator outer core; 13- pipe; 131- long channel; 132- short channel; 133- liquid inlet; 134- liquid outlet mouth.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

The invention relates to a motor stator for an electric vehicle, and its manufacturing method is as follows:

forming the stator core;

making a pipeline mold around the inner core of the stator from a soluble material;

Place the stator core and tube mold into the stator mold cavity, with the tube mold on the outside of the stator core;

Under certain conditions, liquid metal is introduced into the cavity between the inner wall of the stator mold and the outer wall of the stator inner core to form the stator outer core;

After the liquid metal is solidified, the metal preparation is taken out and placed in a solution that can dissolve the pipeline mold, so that the pipeline mold forms a heat dissipation channel.

- The inner core of the stator is formed by laminating multiple thin silicon steel sheets.

- The liquid metal is formed by one or more of copper alloy, aluminum alloy, magnesium alloy and zinc alloy.

- Said certain condition is the introduction of liquid metal under high pressure.

- Said certain condition is that the liquid metal is introduced under vacuum.

The above-mentioned pipeline mold is made of soluble metal salt, and the pipeline mold can be dissolved by the corresponding solution after production.

Referring to Fig. 1, it is a structural schematic diagram of the present invention, including a stator inner core 11 and a stator outer core 12, and a pipeline 13 arranged in the stator outer core 12; , and then formed by dissolving the piping mold.

Referring to Fig. 2 , the schematic diagram of the structure of the stator outer core according to an embodiment of the present invention. The pipeline 13 includes a long channel 131 and a short channel 132, wherein the long channel 131 and the short channel 132 are connected end to end in an "S" shape, and the long channel 131 The short channels 132 are evenly distributed inside the stator outer core 12 along the axial direction of the stator outer core 12 , and the short passages 132 are evenly spaced at both ends of the stator outer core 12 in the circumferential direction of the stator outer core 12 . One end of the pipeline 13 is connected with a liquid inlet 133, and the other end is connected with a liquid outlet 134.

Referring to Fig. 3 , which is a schematic structural view of a stator outer core according to another embodiment of the present invention, the pipe 13 is a spiral pipe arranged inside the stator outer core 12. One end of the pipeline 13 is connected with a liquid inlet 133, and one end is connected with a liquid outlet 134.

Referring to FIG. 4 and FIG. 5 , the stator inner core 11 is formed by pressing a plurality of thin silicon steel sheets 111 .

The present invention has at least the following advantages:

(1) By casting the stator outer core directly on the stator inner core, the gap between the stator inner core and the stator inner core is reduced;

(2) The soluble core is used to make the cooling channel inside the outer core of the stator, which can design the heat dissipation channel to have a larger heat dissipation space, increase the heat exchange area, and improve the heat dissipation capacity;

(3) The manufacturing method of the present invention is simple, can reduce manufacturing steps and save manufacturing cost.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements can also be made without departing from the technical principle of the present invention. and modifications, these improvements and modifications should also be considered as the protection scope of the present invention.

Claims (10)

1. A method for manufacturing a motor stator, comprising the following steps: forming the stator core; making a pipeline mold around the inner core of the stator from a soluble material; Place the stator core and pipe mold into the stator mold cavity, wherein the pipe mold is located outside the stator core; Under certain conditions, liquid metal is introduced into the cavity between the inner wall of the stator mold and the outer wall of the stator inner core to form the stator outer core; After the liquid metal is solidified, the metal preparation is taken out and placed in a solution that can dissolve the pipeline mold, so that the pipeline mold forms a heat dissipation channel. 2. The manufacturing method of a motor stator according to claim 1, wherein the inner core of the stator is formed by laminating multiple thin silicon steel sheets. 3. The manufacturing method of a motor stator according to claim 1, wherein the liquid metal is formed by one or more of copper alloy, aluminum alloy, magnesium alloy and zinc alloy. 4. The manufacturing method of a motor stator according to claim 1, characterized in that: said certain condition is to introduce liquid metal under high pressure. 5. The manufacturing method of a motor stator according to claim 1, characterized in that: said certain condition is to introduce liquid metal under vacuum. 6. A motor stator, characterized in that it comprises: Stator inner core (11); The stator outer core (12) is formed by casting liquid metal to the outside of the stator inner core (11); And the heat dissipation pipeline (13) arranged in the stator outer core (12) is formed by making a pipeline mold before casting the stator outer core (12), and then dissolving the pipeline mold. 7. A motor stator according to claim 6, characterized in that: the pipe (13) includes a long channel (131) and a short channel (132), wherein the long channel (131) and the short channel (132 ) connected end to end in an "S" shape, the long channel (131) is uniformly distributed inside the stator outer core (12) along the axial direction of the stator outer core (12), and the short channel (132) of the stator The outer cores (12) are evenly distributed in the circumferential direction at both ends of the stator outer core (12). 8. A motor stator according to claim 6, characterized in that the pipe (13) is a spiral pipe arranged inside the stator outer core (12). 9. The motor stator according to claim 6, characterized in that: one end of the pipe (13) is connected with a liquid inlet (133), and the other end is connected with a liquid outlet (134). 10. A motor stator according to claim 6, characterized in that: the stator inner core (11) is formed by laminating multiple thin silicon steel sheets (111).