Stator liquid cooling structure and stator structure of stator yokeless disc motor

A stator liquid cooling structure and a stator structure of a stator yokeless disc motor are provided. The cooling structure includes an annular stator bracket and a water jacket. An outer periphery of the stator bracket is in a groove structure and is fixedly connected with the water jacket. Opposite upper and lower ends of the water jacket are provided with a liquid inlet and a liquid outlet. The stator structure includes stator cores, an armature winding, the stator bracket and the water jacket. A first stator core and a second stator core of the stator cores are same in structure and oppositely arranged. The armature winding is wound on first stator tooth bodies and second stator tooth bodies of the stator cores; the first stator tooth bodies and the second stator tooth bodies are inserted into gaps between adjacent blade-shaped cavities and fixed on the stator bracket.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No. 202210678869.6, filed on Jun. 16, 2022, the contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The disclosure belongs to the technical field of disc motors, and particularly relates to a stator liquid cooling structure and a stator structure of a stator yokeless disc motor.

BACKGROUND

The stator yokeless disc motor is compact in structure and has high power density. The huge loss caused by the compact space easily leads to the high temperature rise of the armature winding and damage the insulation of the armature winding. Therefore, how to improve the heat dissipation capacity of the stator core and armature winding has become an urgent problem for technicians in this field.

In the prior art, the motor cooling system usually makes the cooling channel only contact with the armature winding, which often leads to poor cooling effects of the stator core, especially poor heat dissipation of stator tooth shoes.

SUMMARY

Aiming at the problem that the cooling technology of the existing high-power density disc permanent magnet motor is insufficient, the disclosure provides a stator liquid cooling structure and a stator structure of a stator yokeless disc motor.

The present disclosure provides following technical scheme.

The disclosure relates to a stator liquid cooling structure of a yokeless disc motor and the stator liquid cooling structure of the stator yokeless disc motor includes a stator bracket and a water jacket; the stator bracket is annular, and the stator bracket includes an annular groove arranged on an outer periphery of the stator bracket, radial cooling channel sheets, baffle plates, a second circumferential cooling channel disc and a third circumferential cooling channel disc. An outer periphery of the annular groove is fixedly connected with the water jacket and an annular space is formed between the annular groove and the water jacket. The annular space is a first circumferential cooling channel. Opposite upper and lower ends of the water jacket are provided with a liquid inlet and a liquid outlet; and the first circumferential cooling channel is provided with the baffle plates on both sides of an axis where a connecting line between the liquid inlet and the liquid outlet is located. The first circumferential cooling channel is divided into two cavities by two the baffle plates, one cavity is communicated with the liquid inlet and the other cavity is communicated with the liquid outlet. A plurality of the radial cooling channel sheets are arranged at a bottom of the annular groove in a circumferential array towards a center of circle direction, one end of each of the radial cooling channel sheets is communicated with the annular groove, and the other end of the each of the radial cooling channel sheets is closed. The second circumferential cooling channel disc and the third circumferential cooling channel disc are same in structure, are both annular disc structures, and are symmetrically arranged on both sides of the bottom of the annular groove. The second circumferential cooling channel disc and the third circumferential cooling channel disc both include a plurality of blade-shaped cavities arranged in a circumferential array along the second circumferential cooling channel disc and the third circumferential cooling channel disc, and ends of the blade-shaped cavities facing centers of circles of the second circumferential cooling channel disc and the third circumferential cooling channel disc are communicated, other ends of the blade-shaped cavities are fixed on both sides of the bottom of the annular groove, and the gaps exist between adjacent blade-shaped cavities. The blade-shaped cavities corresponding to the second circumferential cooling channel disc and the third circumferential cooling channel disc are communicated through the radial cooling channel sheets.

Optionally, the stator bracket and the water jacket are made of aluminum alloy.

Optionally, a connecting line between the liquid inlet and the liquid outlet and a connecting line between the two baffle plates are mutually equally divided and perpendicular.

A stator structure adopting the stator liquid cooling structure of the stator yokeless disc motor further includes stator cores and an armature winding. The stator cores include a first stator core and a second stator core. The first stator core and the second stator core have a same structure and are oppositely arranged. The first stator core is in an annular structure including a plurality of first stator tooth shoes and a plurality of first stator tooth bodies, and the first stator tooth bodies are integrally arranged on one side of the first stator tooth shoes facing the second stator core. The second stator core is in an annular structure including a plurality of second stator tooth shoes and a plurality of second stator tooth bodies, and the second stator tooth bodies are integrally arranged on one side of the second stator tooth shoes facing the first stator core. Both the first stator tooth bodies and the second stator tooth bodies are wound with the armature winding, and the first stator tooth bodies and the second stator tooth bodies wound with the armature winding are correspondingly inserted into the gaps between adjacent blade-shaped cavities in the stator liquid cooling structure of the stator yokeless disc motor.

Optionally, the stator cores are yokeless stator cores, and a material of the stator cores is one selected from a group consisting of oriented silicon steel sheet, non-oriented silicon steel sheet, soft magnetic composite material and amorphous alloy material, or two or more materials selected from the group are mixed to make the stator cores.

Optionally, the armature winding adopts concentrated winding.

The present embodiment has following beneficial effects.

According to the stator liquid cooling structure and the stator structure of the yokeless disc motor provided by the embodiment, cooling channels are arranged on the stator bracket, so that the cooling liquid contacts with the stator cores and the armature winding at the same time, thereby obviously improving heat dissipation capacity of the stator cores and the armature winding, and enhancing the safety of the motor. Meanwhile, with the enhancement of the cooling effect of the motor, the power density of the motor is improved. The embodiment improves the heat dissipation capacity of the stator cores and the armature winding of the motor, and increases the safety of the motor.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present embodiment will be further described with reference to the attached drawings.

As shown inFIG.1toFIG.3, a stator liquid cooling structure of a stator yokeless disc motor includes a stator bracket3and a water jacket4. The stator bracket3is annular, and the stator bracket3includes an annular groove31arranged on an outer periphery of the stator bracket, radial cooling channel sheets302, baffle plates303, a second circumferential cooling channel disc304and a third circumferential cooling channel disc305. An outer periphery of the annular groove31is fixedly welded with the water jacket4. The annular groove31and the water jacket4may also be connected in other closed ways besides welding. An annular space is formed between the annular groove31and the water jacket4, and the annular space is a first circumferential cooling channel301. Opposite upper and lower ends of the water jacket4are provided with a liquid inlet401and a liquid outlet402. As shown inFIG.2, the first circumferential cooling channel301is provided with the baffle plates303on both sides of an axis where a connecting line between the liquid inlet401and the liquid outlet402is located. The two baffle plates303divide the first circumferential cooling channel301into two cavities, one of the cavities communicates with the liquid inlet401and the other cavity communicates with the liquid outlet402. A plurality of the radial cooling channel sheets302are arranged at a bottom of the groove body of the annular groove31in a circumferential array towards a center of circle direction, one end of each of the radial cooling channel sheets302is communicated with the annular groove31, and the other end of the each of the radial cooling channel sheets302is closed. The second circumferential cooling channel disc304and the third circumferential cooling channel disc305are same in structure, are both annular disc structures, and are symmetrically arranged on both sides of the bottom of the annular groove31. Both the second circumferential cooling channel disc304and the third circumferential cooling channel disc305include a plurality of blade-shaped cavities3041arranged in an array along the second circumferential cooling channel disc and the third circumferential cooling channel disc, and ends of the blade-shaped cavities3041facing centers of circles of the second circumferential cooling channel disc and the third circumferential cooling channel disc are communicated. Other ends of the blade-shaped cavities3041are fixed on both sides of the bottom of the annular groove31. In other words, the cooling liquid in the blade-shaped cavities3041only flows in through the radial cooling channel sheets302, and there are gaps between adjacent blade-shaped cavities3041, and the blade-shaped cavities3041corresponding to the second circumferential cooling channel disc304and the third circumferential cooling channel disc305are communicated through the radial cooling channel sheets302. The first circumferential cooling channel301, the radial cooling channel sheets302, the second circumferential cooling channel disc304and the third circumferential cooling channel disc305are used for filling cooling liquid. The cooling liquid is added from the liquid inlet401, passes through the first circumferential cooling channel301, the radial cooling channel sheets302, the second circumferential cooling channel disc304and the third circumferential cooling channel disc305, and then flows into the radial cooling channel sheets302and the first circumferential cooling channel301and flows out from the liquid outlet402.

As shown inFIG.2, in this embodiment, a connecting line between the liquid inlet401and the liquid outlet402and a connecting line between the two baffle plates303are mutually equally divided and perpendicular. In other words, the stator liquid cooling structure of the stator yokeless disc motor of the present embodiment is equally divided into an upper half portion and a lower half portion. This arrangement is more conducive to the rapid and uniform filling of the first circumferential cooling channel301, the radial cooling channel sheets302, the second circumferential cooling channel disc304and the third circumferential cooling channel disc305by the cooling liquid, thus improving the heat dissipation efficiency.

The stator bracket3may be made of aluminum alloy. The aluminum alloy has the advantages of good strength, easy processing and good corrosion resistance, and the advantages of light weight of the aluminum alloy is conducive to realizing the lightweight of the motor, thus improving a power density and a torque density of the motor.

The water jacket4is also made of aluminum alloy. The water jacket is fixed on the outer side of the stator bracket and forms the first circumferential cooling channel301with the annular groove31of the stator bracket3.

As shown inFIG.1, a stator structure adopting a stator liquid cooling structure of a stator yokeless disc motor further includes stator cores1and an armature winding2. In order to improve the efficiency of the cooling structure, the stator cores1include a first stator core and a second stator core, and the first stator core and the second stator core have the same structure and are oppositely arranged. The first stator core is in an annular structure including a plurality of first stator tooth shoes101and a plurality of first stator tooth bodies103, and the first stator tooth bodies103are integrally arranged on one side of the first stator tooth shoes101facing the second stator core. The second stator core has an annular structure including a plurality of second stator tooth shoes102and a plurality of second stator tooth bodies104, and the second stator tooth bodies104are integrally arranged on the side of the second stator tooth shoes102facing the first stator core. Both the first stator tooth bodies103and the second stator tooth bodies104are wound with the armature winding2, and the first stator tooth bodies103and the second stator tooth bodies104wound with the armature winding2are correspondingly inserted into the gaps between adjacent blade-shaped cavities3041in the stator liquid cooling structure of the stator yokeless disc motor and are fixed on the stator bracket3. A gap between stator cores1, the armature winding2and the stator bracket3may be filled with epoxy resin, so that the stator cores1and the armature winding2are fixed more firmly; meanwhile, the heat transfer performance of the epoxy resin is superior to that of air. The heat transfer performance of the stator cores1and the armature winding2to the cooling channels may also be enhanced by filling the epoxy resin. The first circumferential cooling channel301in the stator liquid cooling structure of the stator yokeless disc motor is used to cool outer diameter parts of the motor stator cores1and the armature winding2, the radial cooling channel sheets302are used to cool adjacent coils of the armature winding2, and the second circumferential cooling channel disc304and the third circumferential cooling channel disc305are used to cool the whole stator cores1and the armature winding2. The stator cores1are yokeless stator cores, and a material of the stator cores1is one selected from a group consisting of oriented silicon steel sheet, non-oriented silicon steel sheet, soft magnetic composite material and amorphous alloy material, or two or more materials selected from the group are mixed to make the stator cores1.

In the embodiment, the cooling liquid is one selected from water, transformer oil, a mixture of ethylene glycol and water, and other cooling liquids may also be selected.

When the motor works normally, the cooling liquid enters the upper half portion of the first circumferential cooling channel301from the liquid inlet401. When the connecting line between the liquid inlet401and the liquid outlet402and the connecting line between the two baffle plates303are mutually equally divided and perpendicular, the two baffle plates303divide the first circumferential cooling channel301into the upper half portion and the lower half portion, as shown in inFIG.2with baffle plates303as divisions. Then the cooling liquid flows along the circumferential direction into the radial cooling channel sheets302between the coils of the armature winding2, and then flows into the second circumferential cooling channel disc304and the third circumferential cooling channel disc305from the radial cooling channel sheets302. After the cooling liquid flows through the upper half portion of the first circumferential cooling channel301, the cooling liquid is blocked by the baffle plates303. At this time, the cooling liquid flows from the second circumferential cooling channel disc304and the third circumferential cooling channel disc305to the radial cooling channel sheets302of the armature winding, then flows to the first circumferential cooling channel301through the radial cooling channel sheets302, and finally flows out through the liquid outlet402. The cooling liquid flowing through the channel is able to directly contact with the first stator tooth shoes101, the second stator tooth shoes103and the armature winding2, and is able to effectively take away the heat generated by the stator cores1and the armature winding2.

A physical model of the motor is established by Solidworks software, and imported into SpaceClaim to obtain the internal fluid of the motor by establishing an air bag and using Boolean operation, and then imported into Mesh for grid meshing. The minimum orthogonality of the whole grid is greater than 0.1 and the maximum distortion is less than 0.98. After meshing, the physical model is imported into Fluent software for calculation. In Fluent software calculation, a default ambient temperature is 300 Kelvin (K), and heat generation rates of motor heating parts and a thermal conductivity of each part need to be specified. In this embodiment, the heat generation rate of stator cores is 6734494 W/m3(watt/cubic meter) and the heat generation rate of the armature winding is 12406102 W/m3, the specified thermal conductivity of each part of the motor is shown in Table 1.

A temperature field distribution of the motor calculated by the Fluent software is shown inFIG.4toFIG.7.FIG.4andFIG.5respectively show the temperature distribution of the stator cores and the armature winding of the motor when only the cooling structure is provided on the surface of the stator bracket. As is be seen from theFIG.4andFIG.5, the highest temperature of the stator cores and the armature winding is located at the inner diameter of the motor, and the highest temperature rise is 469.76 K and 447.64 K respectively.FIG.6andFIG.7respectively shows the temperature distribution of the stator cores and the armature winding of the motor according to the cooling structure of the present embodiment. As is seen from theFIG.6andFIG.7that the highest temperature rise of the stator cores and the armature winding of the motor is 398.48 K and 381.75 K, respectively. Compared with the previous cooling structure, the temperature rise of the motor is significantly reduced, proving the effectiveness of the cooling structure of the present embodiment.