Stator cooling structure, motor, compressor and refrigeration equipment

Abstract

The invention discloses a stator cooling structure, a motor, a compressor and refrigeration equipment, and the stator cooling structure comprises a stator which is provided with a central through hole for installing a rotor; a cooling spiral flow channel and a cooling storage cavity are arranged in the stator, the cooling spiral flow channel is arranged around the central through hole, and the cooling storage cavity is arranged around the radial outer side of the cooling spiral flow channel; an outlet of the cooling spiral flow channel communicates with the cooling storage cavity to form an inner side cooling inlet, and a liquid spraying hole communicating with the cooling storage cavity is formed in the end face of the stator. By arranging the cooling spiral flow channel and the cooling storage cavity in the stator, multi-layer sufficient cooling of the interior of the stator is achieved, the running reliability of the motor is improved, and it is ensured that a compressor and refrigeration equipment can stably run for a long time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to a stator cooling structure, an electric machine, a compressor and a refrigeration device. BACKGROUND

[0002] As the core power device in the industrial field, electric machines are widely used in various mechanical equipment, and the cooling performance of the stator thereof is directly related to the operating efficiency, reliability and service life of the electric machine. In ordinary electric machines, the stator cooling is usually performed by external air cooling or simple liquid cooling, for example, a cooling channel is arranged on the stator shell, and heat exchange is performed by air or cooling fluid. However, this basic cooling method can still meet the demand under low load or stable working conditions, but under high power density, high frequency start-stop or variable working condition operating conditions, problems such as insufficient cooling and uneven temperature distribution often occur, which leads to local overheating of the stator, accelerated aging of the insulating material, and even causes electric machine failure.

[0003] With the expansion of the application scenarios of electric machines, especially in high-load devices such as compressors, the cooling demand of electric machines becomes more demanding. As a key device for gas compression and delivery, the driving electric machine of the compressor needs to be continuously operated in a high-speed and high-pressure environment, generating a large amount of heat. The simple cooling structure of the traditional electric machine is difficult to adapt to the special working conditions of the compressor, for example, in reciprocating compressors or screw compressors, the electric machine stator is frequently subjected to impact load and vibration, and the cooling efficiency is easily disturbed, which may cause heat accumulation.

[0004] As a typical representative of speed-type compressors, centrifugal compressors have extremely high rotational speed (usually up to tens of thousands of revolutions per minute) of the electric machine, which puts higher requirements on the cooling of the stator. The existing electric machine stator cooling scheme of the centrifugal compressor usually adopts a spiral flow channel opened on the outside of the stator, and the cooling medium flow is controlled by a regulating valve, so that the cooling medium sequentially cools the outer surface of the stator along the flow channel, and finally cools the electric machine wire package through the outlet. Although this method can alleviate the stator temperature rise problem to some extent, it has significant limitations: first, the cooling level is single, and only shallow cooling of the outer wall of the stator can be achieved, and the core area inside the stator cannot be deeply cooled; second, under high temperature or variable working condition, uneven distribution of the cooling medium can easily lead to an increase in the radial and axial temperature gradient of the stator, causing thermal stress concentration and affecting the operating stability of the whole machine.

[0005] Therefore, how to design a stator cooling structure capable of achieving multi-level sufficient cooling is a technical problem to be solved in the industry. SUMMARY

[0006] In order to solve the defects of low cooling efficiency, poor temperature uniformity and insufficient high temperature adaptability in the prior art, the application provides a stator cooling structure, a motor, a compressor and a refrigeration equipment, a cooling spiral flow channel and a cooling storage cavity are arranged in the stator, the stator inside is fully cooled in multiple layers, the reliability of motor operation is improved, and the compressor and the refrigeration equipment can be stably operated for a long time.

[0007] The technical scheme adopted by the application is that a stator cooling structure is designed, which comprises: a stator provided with a central through hole for mounting a rotor; a cooling spiral flow channel and a cooling storage cavity are arranged in the stator, the cooling spiral flow channel is arranged around the central through hole, the cooling storage cavity is arranged on the radial outer side of the cooling spiral flow channel, and the cooling spiral flow channel and the cooling storage cavity are communicated, and the end face of the stator is provided with a liquid injection hole communicated with the cooling storage cavity.

[0008] Further, the inlet of the cooling spiral flow channel penetrates the outer wall of the stator to form an outer side cooling inlet, the outer side cooling inlet is close to the front end of the stator, the outlet of the cooling spiral flow channel is communicated with the cooling storage cavity to form an inner side cooling inlet, the inner side cooling inlet is close to the rear end of the stator, and the liquid injection hole is arranged on the front end face of the stator.

[0009] Further, the aperture of the liquid injection hole is D1, the cooling storage cavity is in the shape of a ring, the ring width of the cooling storage cavity is D2, and the ratio of D1 to D2 is in the range of 0.4 to 0.5.

[0010] Further, the stator has a cylindrical body, the cylindrical body is sequentially divided into a front section, a middle section and a rear section along the axial direction, and the cooling spiral flow channel and the cooling storage cavity are arranged in the middle section.

[0011] Further, the length of the middle section is L2, the length of the cylindrical body is L, and the ratio of L2 to L is in the range of 0.7 to 0.8.

[0012] Further, the silicon steel sheet of the middle section is provided with an opening, and the openings of any two adjacent silicon steel sheets are offset by a set angle a to form the cooling spiral flow channel.

[0013] Further, the set angle a is in the range of 5° to 10°.

[0014] Further, the length of the front section is L1, the length of the rear section is L3, the front section is formed by stacking 8 to 10 silicon steel sheets, and the rear section is formed by stacking 5 to 10 silicon steel sheets.

[0015] The application also provides a motor, which comprises: a stator provided with a central through hole and a rotor movably mounted in the central through hole, and the stator adopts the above-mentioned stator cooling structure, and the refrigerant sprayed out of the liquid injection hole flows out through the gap between the stator and the rotor.

[0016] The application further provides a compressor driven by the motor.

[0017] In some embodiments, the compressor is a centrifugal compressor.

[0018] The application further provides a refrigeration device comprising the compressor.

[0019] Compared with the prior art, the application sets a cooling spiral flow channel and a cooling storage cavity inside the stator, the refrigerant cools the inner layer of the stator via the cooling spiral flow channel, then enters the cooling storage cavity for storage and cooling of the middle layer of the stator, and when the refrigerant in the cooling storage cavity reaches a certain amount, the refrigerant is sprayed out through the liquid injection hole on the end surface of the stator to cool the wire package of the end portion of the stator. The cooling structure can fully cool the inside of the stator in multiple layers, improve the reliability of the motor operation, and ensure long-term stable operation of the compressor and the refrigeration device. BRIEF DESCRIPTION OF DRAWINGS

[0020] The application will be described in detail below in combination with embodiments and drawings, in which:

[0021] Figure 1 is a sectional view of the stator cooling structure of the application;

[0022] Figure 2 is a flow direction view of the stator cooling structure of the application;

[0023] Figure 3 is a front end surface view of the stator body of the application;

[0024] Figure 4 is a first silicon steel sheet view of the middle section of the stator of the application;

[0025] Figure 5 is a second silicon steel sheet view of the middle section of the stator of the application;

[0026] Figure 6 is a third silicon steel sheet view of the middle section of the stator of the application;

[0027] Figure 7 is a superimposed view of the first three silicon steel sheets of the middle section of the stator of the application;

[0028] Figure 8 is a front side silicon steel sheet view of the front section of the stator of the application;

[0029] Figure 9 is a rear side silicon steel sheet view of the front section of the stator of the application;

[0030] Explanation of reference numerals in the attached drawings: 1. Stator; 2. Cooling spiral channel; 3. Cooling storage cavity; 4. Spray hole; 5. Inner cooling inlet; 6. Outer cooling inlet; 7. Stator front end coil; 8. Stator rear end coil; 9. Opening; 10. Center through hole. Detailed Implementation

[0031] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] like Figures 1 to 3 As shown, the stator cooling structure of the present invention mainly includes a stator 1, a cooling spiral channel 2, a cooling storage cavity 3, and spray holes 4. The stator 1 is provided with a central through hole 10 for mounting the rotor, through which the rotor moves. The cooling spiral channel 2 and the cooling storage cavity 3 are both embedded inside the stator 1. The cooling spiral channel 2 is spiral-shaped and arranged around the central through hole 10. The cooling storage cavity 3 surrounds the radial outer side of the cooling spiral channel 2 and is connected to the cooling storage cavity 3. The spray holes 4 are evenly distributed on the end face of the stator 1 and are connected to the cooling storage cavity 3.

[0033] This design incorporates a cooling spiral channel 2 and a cooling storage cavity 3 inside the stator 1. Refrigerant flows through the cooling spiral channel 2 to cool the inner layer of the stator 1. The outflowing refrigerant then enters the cooling storage cavity 3 for storage and further cooling of the middle layer of the stator 1. When the refrigerant in the cooling storage cavity 3 reaches a certain level, it is then sprayed out through the spray nozzles 4 on the end face of the stator 1 to cool the coils at the stator ends. This cooling structure provides multi-layered and thorough cooling of the stator 1, improving the reliability of motor operation and ensuring the long-term stable operation of the compressor and refrigeration equipment.

[0034] like Figure 2 As shown, in a preferred embodiment of the present invention, the inlet of the cooling spiral channel 2 penetrates the outer wall of the stator 1 to form an outer cooling inlet 6, and the outer cooling inlet 6 is close to the front end of the stator 1. The outlet of the cooling spiral channel 2 is connected to the cooling storage cavity 3 to form an inner cooling inlet 5, and the inner cooling inlet 5 is close to the rear end of the stator 1. The spray hole 4 is provided on the front end face of the stator 1. The refrigerant enters the cooling spiral channel 2 from the outer cooling inlet 6, flows from "front" to "back", enters the cooling storage cavity 3 from the inner cooling inlet 5, and then flows from "back" to "front". Finally, it is sprayed out from the spray hole 4, that is, the refrigerant flows back and forth inside the stator 1.

[0035] It should be noted that the front end of the stator 1 is the direct connection part of the motor and the load, which bears the most concentrated electromagnetic load and mechanical load, so that the temperature of the front end of the stator is relatively high. In the electromagnetic aspect, the end effect causes the magnetic field distribution in the front end region of the stator to be distorted, resulting in eddy current loss and hysteresis loss being significantly higher than other parts; at the same time, as the main connection point of power input, the front end wire package bears the highest current density, and the heat generated is particularly concentrated. In terms of heat dissipation, the front end is usually equipped with end covers, bearings and other components, which to some extent hinder the radial conduction of heat, so that the thermal resistance of this area is relatively large.

[0036] And the present application builds a front-back-front return flow path inside the stator 1, so that the cooling mechanism can exchange heat in both directions. The coolant first flows through the front end region with higher temperature, absorbs heat and continues to flow to the rear end, avoiding the accumulation of heat at the front end of the stator 1, balancing the temperature gradient in the axial direction of the stator, and the return flow path makes the effective flow length of the coolant inside the stator 1, prolongs the heat exchange time, and effectively improves the heat exchange efficiency. This compact layout is especially suitable for space-limited scenarios such as motors.

[0037] As shown in Figures 1 to 3 As a preferred solution, the hole diameter of the liquid injection hole 4 is D1, the cooling storage cavity 3 is circular, and the ring width of the cooling storage cavity 3 is D2, and the ratio of D1 to D2 is in the range of 0.4 to 0.5. This design aims to form a reasonable pressure difference at the liquid injection hole 4 during the inner layer cooling process of the stator 1 to promote the effective injection of the coolant. If the hole diameter D1 of the liquid injection hole 4 is too small, the flow of the coolant injected per unit time will be insufficient, which cannot fully cool the front end wire package 7 of the stator, and the heat generated in the wire package area will accumulate, which is easy to cause local overheating of the stator 1, and in severe cases, it may cause burning. On the contrary, if the hole diameter D1 of the liquid injection hole 4 is too large, the pressure difference formed is insufficient, the flow rate of the coolant is reduced, and the total cooling flow is reduced, so the heat that can be taken away from the wire package per unit time is limited, which also causes the risk of overheating and burning. Therefore, by limiting the ratio of D1 to D2 to be in the range of 0.4 to 0.5, the coolant can obtain a suitable flow rate and cross-sectional area combination at the liquid injection hole 4, thereby forming the best cooling flow to meet the heat dissipation needs of the stator wire package and ensure the stable operation of the motor.

[0038] As shown in Figure 1 , 2As shown, in the preferred embodiment of the present application, the stator 1 has a cylindrical body, which is sequentially divided into a front section (length L1), a middle section (length L2), and a rear section (length L3) along its axial direction, and the cooling spiral flow channel 2 and the cooling storage cavity 3 are both arranged in the middle section, which has an outer cooling inlet 6 and an inner cooling inlet 5 inside. The refrigerant first receives the refrigerant that has completed the preliminary cooling of the outer surface of the stator 1 through the outer cooling inlet 6, then enters the cooling spiral flow channel 2 coiled in the middle section, and realizes the cooling of the inner layer of the stator 1, and then flows into the cooling storage cavity 3 through the outlet of the cooling spiral flow channel 2 (the connection point constitutes the inner cooling inlet 5), realizing the internal cooling of the stator 1. As the refrigerant flowing into the cooling storage cavity 3 increases, the refrigerant completes the temporary storage and pressure balance in the cavity, and finally is directly sprayed through the liquid injection hole 4 on the end surface of the stator 1 to cool the front end wire package 7 of the stator.

[0039] This design utilizes the cooling spiral flow channel 2 and the cooling storage cavity 3 in the middle section to jointly construct a multi-structure and multi-level stator cooling structure. By connecting different cooling flow channels and cavities in series, the cooling path is lengthened and the heat exchange area is expanded, ensuring that the refrigerant can absorb and carry away the heat of each region of the stator in layers and in order.

[0040] The middle section structure is the key position of the internal cooling of the entire stator, and its size is an important parameter for ensuring uniform cooling of the stator. The length of the middle section is L2, and the length of the cylindrical body is L. The preferred ratio of L2 to L is in the range of 0.7 to 0.8.

[0041] Setting the ratio of L2 to L to be greater than 0.7 means that more than 70% of the length of the stator body can obtain direct and efficient internal cooling. The longer middle section provides sufficient axial length for the cooling spiral flow channel 2, which allows the refrigerant to have a longer path and time to exchange heat with the stator 1, avoiding the phenomenon that the refrigerant flows out without being fully heated due to a too short cooling process, thereby improving the utilization efficiency of the refrigerant and the overall cooling capacity. Moreover, a uniform and sufficient cooling path helps to establish a more gentle temperature distribution along the entire length L2 of the middle section. If the length L2 of the middle section is too short, cooling may be concentrated in a local area, resulting in significant hot spots and large temperature gradients along the axial direction of the stator 1, which may cause thermal stress and affect the insulation life. Therefore, maintaining the length L2 of the middle section to be greater than 0.7 ensures that the stator body has a large enough effective heat exchange area, promotes the uniformity of the temperature field, and enables the refrigerant to fully absorb and carry away most of the heat generated by the stator 1 during operation, thereby fundamentally avoiding the problem of excessive overall temperature rise of the stator 1 due to insufficient cooling, and improving the reliability of the motor operation.

[0042] The ratio of L2 to L is set to be less than or equal to 0.8, which reserves the necessary structural length for the front end and rear section of the stator 1. The front section needs sufficient thickness to open the liquid injection hole 4 and withstand the refrigerant pressure of the cooling storage cavity 3 to prevent deformation; the rear section will also withstand the refrigerant pressure of the cooling storage cavity 3, and also needs sufficient thickness to ensure strength. Therefore, the length of the middle section L2 is controlled to be less than or equal to 0.8 to prevent the front and rear sections from being squeezed due to the excessive length of the middle section, to ensure the mechanical strength and stability of the stator 1 as a whole, and to avoid structural risks under the combined action of electromagnetic force and refrigerant pressure.

[0043] As shown in Figures 4 to 7 , in the middle section structure design of the stator 1, each silicon steel sheet is provided with an opening 9, and the openings 9 of adjacent silicon steel sheets are arranged to be offset by a set angle a to form a continuous cooling spiral flow channel 2. The accurate control of the set angle a is a key parameter to ensure the cooling effect, which needs to be strictly limited within a reasonable range: when the set angle a is too large, the openings 9 of adjacent silicon steel sheets cannot be effectively connected after being stacked, which destroys the continuity of the cooling spiral flow channel 2, blocks the flow of the refrigerant, significantly reduces the cooling effect of the middle section, increases the temperature of the stator 1, and finally causes insulation aging or even burning accident; on the contrary, if the set angle a is too small, under the same axial space constraint, the effective cooling length of the cooling spiral flow channel 2 is insufficient, which also leads to insufficient heat dissipation capacity and temperature rise of the stator 1 exceeding the safe range. According to theoretical calculation and experimental verification, the set angle a is controlled within the range of 5° to 10°, which can not only ensure the complete formation of the cooling spiral flow channel 2, but also provide sufficient heat exchange area and flow channel length, to ensure that the middle section of the stator 1 obtains sufficient and uniform cooling effect.

[0044] As shown in Figure 8 , 9 , in the front section structure design of the stator 1, the front section of the stator 1 is in the form of a circular ring and is stacked by a plurality of silicon steel sheets. The number of silicon steel sheets in the front section needs to be strictly controlled, too many will lead to insufficient length of the middle section, and thus insufficient cooling of the inner layer of the stator 1; too few will make the front end structure weak and prone to deformation under the pressure of the refrigerant in the cooling storage cavity 3, which cannot meet the strength requirement and finally leads to motor failure. In addition, all the silicon steel sheets in the front section are provided with liquid injection ports 4, which function to form a local pressure rise when the refrigerant in the cooling storage cavity 3 flows out, to realize directional liquid cooling of the stator front end wire package 7. At the same time, the outer cooling inlet 6 provided on the silicon steel sheet can guide the refrigerant that has completed preliminary cooling through the outer surface of the stator 1 into the cooling spiral flow channel 2 of the middle section, thereby effectively cooling the inner layer of the stator 1.

[0045] Therefore, the number of silicon steel sheets in the front section is limited to 8 to 10, and the thickness of the 8 to 10 layers of silicon steel sheets not only ensures that the front section has excellent anti-deformation ability and can effectively resist the impact of refrigerant pressure fluctuations, but also avoids excessive thickening leading to excessive length of the path and insufficient pressure of the liquid injection hole.

[0046] In the design of the rear section structure of stator 1, its importance is lower than that of the middle section and the front section. The length L3 of the rear section only needs to meet the reasonable strength requirements. In practical applications, it can be the same size as the front section or slightly thinner than the front section. Therefore, the number of silicon steel sheets in the rear section is limited to 5 to 10 sheets.

[0047] like Figures 1 to 3 As shown, the present invention also proposes an electric motor, including: a stator 1 with a central through hole 10 and a rotor movably installed in the central through hole. The stator 1 adopts the stator cooling structure described above, and the refrigerant sprayed from the injection hole 4 flows out through the gap between the stator 1 and the rotor.

[0048] This cooling structure features a cooling spiral channel 2 and a cooling storage cavity 3 inside the stator 1. The refrigerant cools the inner layer of the stator 1 through the cooling spiral channel 2, and then enters the cooling storage cavity 3 for storage and to cool the middle layer of the stator. When the refrigerant in the cooling storage cavity 3 reaches a certain amount, it is sprayed out through the spray hole 4 on the end face of the stator 1 to cool the coil at the end where the spray hole 4 is located. The refrigerant then flows through the gap between the stator 1 and the rotor to the other end of the stator 1 to cool the rotor and the coil at the other end of the stator 1. During the flow of the refrigerant, the interior of the stator 1 is fully cooled in multiple layers, improving the reliability of motor operation.

[0049] like Figure 1 , 2 As shown, this invention also proposes a compressor, which is driven by the aforementioned motor. The stator 1, as the core component of the motor, has its cooling structure optimized through the aforementioned spiral flow channel and sealing cavity design. The refrigerant cooling path is as follows: refrigerant is introduced from outside the motor → outside of the stator → outer cooling inlet 6 → cooling spiral flow channel 2 → inner cooling inlet 5 → cooling storage cavity 3 → spray hole 4 → gap between stator 1 and rotor → rear end of stator 1 → refrigerant is delivered out of the motor.

[0050] The motor is axially arranged, with the front end of stator 1 facing the compressor as the driving end, and the rear end of stator 1 as the non-driving end, away from the compressor and typically facing the external environment. Stator 1 is fixed inside the motor housing, and the rotor is movably mounted in the central through-hole 10 of stator 1, maintaining a small gap between them to ensure electromagnetic efficiency while providing a channel for refrigerant flow. The injection hole 4 at the front end of stator 1 is located on the end face, facing the compressor, allowing refrigerant injection to directly target high-temperature areas. After being injected, the refrigerant flows in reverse into the gap between stator 1 and rotor under pressure differential, achieving synchronous cooling of the front and rear ends of the stator and the rotor, thereby effectively extending the motor's lifespan and ensuring long-term stable operation of the compressor.

[0051] In some embodiments, the compressor is a centrifugal compressor. A large amount of heat is generated when the centrifugal compressor is running, and the traditional motor cooling system is often difficult to cope with the continuous high temperature working condition, and the present application realizes efficient cooling through the multi-level cooling structure of the cooling spiral flow channel 2 and the cooling storage cavity 3 arranged inside the stator, combined with the reverse flow path of the refrigerant, and the overall temperature of the stator is lower than 15-20℃ compared with the traditional cooling structure, which meets the heat dissipation demand of the centrifugal compressor running under full load and high temperature working condition.

[0052] As shown in Figure 1 The present application also proposes a refrigeration equipment, which comprises a compressor driven by the motor described above, and the stator 1 as the core component of the motor has been optimized in cooling structure through the spiral flow channel and the sealing cavity design described above, ensuring the long-term stable operation of the compressor and the refrigeration equipment.

[0053] In some feasible embodiments, the stator cooling structure is connected to the refrigerant circulation loop of the refrigeration equipment through branch pipes, and the refrigerant is usually introduced from the refrigerant circulation loop, and after absorbing heat, the refrigerant is sent back to the refrigerant circulation loop.

[0054] As shown in Figure 2 For the sake of understanding, the stator cooling structure is connected to the outlet side of the condenser through the inlet branch pipe and to the inlet side of the evaporator through the outlet branch pipe, for example, the high-pressure normal-temperature liquid refrigerant passes through the cooling throttling element, and its pressure and temperature drop sharply, becoming a low-temperature low-pressure gas-liquid two-phase mixture. The low-temperature refrigerant is introduced to the outside of the stator 1, and the cooling inlet 6 on the outside enters the cooling spiral flow channel 2 around the stator 1, absorbs heat, and flows into the cooling storage cavity 3, temporarily stores and cools the middle layer of the stator, and finally sprays out from the spray hole 4 at the front end of the stator 1 to cool the stator front-end wire package 7. In this process, most of the liquid refrigerant evaporates rapidly, and then the low-temperature low-pressure gaseous refrigerant that has completely or basically gasified flows to the rear end of the stator 1 along the gap between the stator 1 and the rotor under the action of pressure difference, and at the same time, cools the stator rear-end wire package 8. Finally, the low-pressure refrigerant gas after completing the cooling task returns to the evaporator through the outlet branch pipe, completing an independent cooling cycle.

[0055] It should be noted that the terms used above are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. When the terms "comprise" and / or "include" are used in the specification, they indicate the presence of a feature, step, operation, device, component, and / or combination thereof. The order of actions, steps, etc. in the devices and methods shown in the specification can be implemented in any order as long as the output of the previous process is not used in the subsequent process, unless the order is specifically limited. The use of similar ordinal terms does not mean that the implementation must be in such an order.

[0056] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art(s) can not be discussed in detail herein. However, where appropriate, such techniques, methods, and apparatus should be considered as being part of the specification. In the interests of brevity and clarity, all examples shown and discussed herein are illustrative only and not intended to be limiting. Thus, other examples of the exemplary embodiments can be used in which different values are substituted for the values used in this example, and that such examples are to be considered as equivalents. It should be noted that like numbers and letters refer to like items throughout the following figures, and that, where appropriate, a discussion of one figure can apply to like items in another figure.

[0057] The above description is embodied in the form of a preferred embodiment only and is not intended to limit the present application. Any modification, equivalent replacement and improvement made without departing from the spirit and principle of the present application shall fall within the scope of the present application.

Claims

1. A stator cooling structure comprising: The stator is provided with a central through hole for mounting the rotor; characterized in that a cooling spiral flow channel is arranged around the central through hole inside the stator, and a cooling storage cavity is arranged on the radial outside of the cooling spiral flow channel, and the cooling spiral flow channel and the cooling storage cavity are in communication, and the end face of the stator is provided with a liquid injection hole in communication with the cooling storage cavity.

2. The stator cooling structure according to claim 1, characterized by The inlet of the cooling spiral flow channel forms an outside cooling inlet through the outer wall of the stator, which is close to the front end of the stator, and the outlet of the cooling spiral flow channel is in communication with the cooling storage cavity to form an inside cooling inlet, which is close to the rear end of the stator, and the liquid injection hole is arranged on the front end face of the stator.

3. The stator cooling structure according to claim 1, characterized by, The hole diameter of the liquid injection hole is D1, the cooling storage cavity is in the shape of a circular ring, the ring width of the cooling storage cavity is D2, and the ratio of D1 to D2 is in the range of 0.4 to 0.

5.

4. The stator cooling structure according to any one of claims 1 to 3, characterized by, The stator has a cylindrical body, which is divided into a front section, a middle section and a rear section along its axial direction in sequence, and the cooling spiral flow channel and the cooling storage cavity are both arranged in the middle section.

5. The stator cooling structure according to claim 4, characterized by The length of the middle section is L2, and the length of the cylindrical body is L, and the ratio of L2 to L is in the range of 0.7 to 0.

8.

6. The stator cooling structure according to claim 4, characterized by The middle section is provided with an opening on the silicon steel sheet, and the openings of any two adjacent silicon steel sheets are offset by a set angle a to form the cooling spiral flow channel.

7. The stator cooling structure according to claim 6, characterized by The value of the set angle a is in the range of 5° to 10°.

8. The stator cooling structure of claim 4, wherein The length of the front section is L1, and the length of the rear section is L3, the front section is formed by stacking 8 to 10 silicon steel sheets, and the rear section is formed by stacking 5 to 10 silicon steel sheets.

9. An electric machine comprising: The stator provided with a central through hole and the rotor movably mounted in the central through hole, characterized in that the stator adopts the stator cooling structure of any one of claims 1 to 8, and the refrigerant sprayed out of the liquid injection hole flows out through the gap between the stator and the rotor.

10. Compressor, characterized in that The compressor is driven to operate by the motor of claim 9.

11. The compressor of claim 10, wherein, The compressor is a centrifugal compressor.

12. A refrigeration appliance characterised in that, Comprising: The compressor of claim 10 or 11.

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