Heat dissipation structure of motor stator winding
The introduction of a thermally conductive structural layer between the stator winding ends and core addresses inefficiencies in existing motor cooling systems, enhancing heat dissipation and motor lifespan through direct heat transfer.
Patent Information
- Application Number
- CN201910965031.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-10-11
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2039-10-11
AI Technical Summary
Existing motor stator winding heat dissipation structures are inefficient and complex, leading to high temperatures and limited cooling capabilities, particularly at the winding ends, which can hinder the motor's performance and lifespan.
A heat dissipation structure for motor stator windings that includes a thermally conductive structural layer between the winding ends and the stator core, utilizing materials like thermally conductive adhesive graphene or silicone grease to facilitate direct heat transfer from the winding ends to the stator core for efficient dissipation.
The proposed solution enhances heat dissipation efficiency by establishing a direct heat conduction path from the winding ends to the stator core, reducing temperature rise and improving the motor's overall cooling capacity without altering its assembly structure, thereby extending its service life.
Smart Images
Figure CN110581625B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of heat dissipation of motor stator windings, and in particular to a heat dissipation structure of motor stator windings. Background Art
[0002] The heat source of the motor comes from its own loss, including core loss, winding loss and mechanical loss. Core loss includes the core loss generated when the main magnetic field in the core changes. This loss is generally called basic loss. At the same time, the motor itself is a combination of multiple materials. Its heating process is relatively complex, so its temperature rise process is also relatively complex, but under a certain capacity, the temperature rise of each part is certain, and the temperature distribution is also certain. Then in terms of heat source, the proportion of general small motor losses is: stator copper loss> rotor copper loss> iron loss> mechanical loss. Therefore, the heat generated by the stator copper loss can be evaporated more efficiently, or the heat generated by the stator copper loss can be directed to a structure that is easier to dissipate heat through a more effective heat transfer effect, thereby reducing the overall operating temperature of the motor, which can extend the practical life of the motor, and improve the design efficiency. In the existing heat dissipation methods, there are mainly water hydrogen cooling, full hydrogen cooling, double water internal cooling and full air cooling. However, this method relies on fans and external water cooling shells, the cooling effect is not good, and it relies on multi-layer external structures, which brings certain hidden dangers and limitations to the operation of the motor.
[0003] Therefore, there is an urgent need on the market for a stator winding heat dissipation structure with good heat dissipation effect and reasonable structure. Summary of the invention
[0004] In view of the deficiencies in the above technology, the present invention provides a method to solve the problem that the existing motor heat dissipation structure mentioned in the above background technology is too complicated and has low efficiency.
[0005] To achieve the above-mentioned purpose, the present invention provides a heat dissipation structure of a motor stator winding, comprising a stator core and a stator winding wound on the stator core, an insulating sleeve is arranged between the stator winding and the stator core, both ends of the stator winding extending out of the stator core form winding ends, a heat-conducting structural layer is arranged between the winding ends and the stator core, and the heat-conducting structural layer is an insulating material; the heat-conducting structural layer is coated on the side surface of the winding end, and the heat-conducting structural layer is in close contact with the stator core, and the heat of the winding end is conducted from the heat-conducting structural layer to the surface of the stator core for heat dissipation.
[0006] Preferably, the heat-conducting structural layer completely covers the side surface of the winding end on one side to form an annular structure sleeved on the winding end and in close contact with the stator core.
[0007] Preferably, the heat-conducting structure layer is in close contact with the stator core and extends along the outer surface of the stator core toward the winding end at the other end, and the heat of the stator core is conducted to the heat-conducting structure layer for heat dissipation.
[0008] Preferably, the heat-conducting structural layer completely covers the side surface of the winding end, extends along the stator winding to the heat dissipation space in the insulating sleeve, and conducts the heat of the stator winding through the heat-conducting structural layer.
[0009] Preferably, the heat-conducting structure layer extending into the insulating sleeve is a non-sealed filling structure, and the heat of the stator winding is conducted through the heat-conducting structure layer and dissipated by heat convection through the heat dissipation space between the stator winding and the insulating sleeve.
[0010] Preferably, the winding ends on both sides are respectively provided with a first heat-conducting structural layer and a second heat-conducting structural layer; the first heat-conducting structural layer is coated on the side surface of the winding end and is in close contact with the stator core, and the heat of the stator winding is conducted from the first heat-conducting structural layer to the surface of the stator core for dissipation; the second heat-conducting structural layer is filled in the heat dissipation space between the stator winding and the insulating sleeve, and the heat of the stator winding is dissipated by conducting heat through the second heat-conducting structural layer.
[0011] Preferably, the first heat-conducting structure layer is in close contact with the stator core and extends along the outer surface of the stator core toward the winding end at the other end, and the heat of the stator core is conducted to the first heat-conducting structure layer for heat dissipation.
[0012] Preferably, the second heat-conducting structural layer extending into the insulating sleeve is a non-sealed filling structure, and the heat of the stator winding is conducted through the second heat-conducting structural layer and dissipated by heat convection through the heat dissipation space between the stator winding and the insulating sleeve.
[0013] Preferably, the thermally conductive structural layer is one of thermally conductive adhesive graphene, thermally conductive silicone grease, thermally conductive paste, heat dissipating paste, and heat dissipating silica gel.
[0014] Preferably, the heat-conducting structural layer is arranged on the side surface of the winding end by filling, and is in close contact with the stator core.
[0015] The beneficial effects of the present invention are as follows: in the prior art, the heat dissipation of the stator winding is basically carried out by the fan in the motor, and because the stator winding is isolated from the silicon steel sheet by an insulating sleeve, the heat transfer and dissipation are hindered, and the temperature rise of the stator winding is relatively high, so there are many cooling designs for the stator winding, such as the more common external water cooling circulation system, stator evaporative cooling system, etc. Such existing design systems require large-scale structural additions to the existing structure of the motor, but for some motors with relatively small volume and relatively limited installation environment, this heat dissipation method will be limited and the heat dissipation structure is too complicated.
[0016] In the present invention, a stator core and a stator winding wound on the stator core are included, an insulating sleeve is arranged between the stator winding and the stator core, both ends of the stator winding extending out of the stator core form winding ends, a heat-conducting structural layer is arranged between the winding ends and the stator core, and the heat-conducting structural layer is an insulating material; the heat-conducting structural layer is coated on the side surface of the winding end, and the heat-conducting structural layer is in close contact with the stator core, and the heat of the stator winding is conducted from the heat-conducting structural layer to the surface of the stator core for heat dissipation; because the temperature rise of the stator winding is most serious in the coil at the end, and there is also a layer of insulating sleeve between the stator winding and the stator core, which reduces the efficiency of heat conduction; and the heat-conducting material in the present invention is in direct contact with the stator winding and the stator core, so as to set up a high-efficiency heat conduction channel between the stator winding and the stator core, and from the overall structure of the motor, it does not affect the volume and assembly structure of the motor, and improves the heat dissipation capacity of the stator winding while also improving the working life of the motor. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a three-dimensional diagram of the existing stator winding;
[0018] Figure 2 A perspective view of the present invention;
[0019] Figure 3 An exploded view of the present invention;
[0020] Figure 4 It is a cross-sectional view of the present invention.
[0021] The main component symbols are described as follows:
[0022] 1. stator core; 2. stator winding; 21. winding end; 3. insulating sleeve; 4. heat-conducting structure layer; 41. first heat-conducting structure layer. DETAILED DESCRIPTION
[0023] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with the accompanying drawings.
[0024] The present invention provides a heat dissipation structure of a motor stator winding. Figure 2 , including a stator core 1 and a stator winding 2 wound on the stator core, an insulating sleeve 3 is arranged between the stator winding 2 and the stator core 1, both ends of the stator winding 2 extending out of the stator core 1 form winding ends 21, a heat-conducting structure layer 4 is arranged between the winding end 21 and the stator core 1, and the heat-conducting structure layer 4 is an insulating material; the heat-conducting structure layer 4 is coated on the side surface of the winding end 21, and the heat-conducting structure layer 4 is in close contact with the stator core 1, and the heat of the winding end 21 is transferred from the heat-conducting structure layer 4 to the surface of the stator core 1 for heat dissipation. Because the motor itself needs to insulate the stator winding and the stator core, please refer to Figure 1 Therefore, in the motor structure, the stator winding and the stator core are not in direct contact, that is, there is an insulating sleeve in the middle that acts as a heat convection effect and a heat transfer barrier. Therefore, for the end of the stator winding, its temperature rise is the highest relative to other parts of the motor, but there is no effective heat dissipation measure, so for the motor, cooling is the first difficulty and pain point. In the present invention, by filling a thermal conductive material layer between the winding end and the stator core, a heat-conducting structural layer is built between the winding end and the stator core, which is the main way of solid heat transfer. In the stator structure of the original motor, the stator winding is arranged in an insulating tube with a certain heat dissipation space, and then the insulating tube is in contact with the silicon steel sheet, but the heat conduction efficiency is very low. For example, the thermal conductivity of air is 0.01-0.04W / mK, which means that the heat transfer efficiency from the stator winding to the stator core is very low. Therefore, a thermal conductive structural layer is used to fill this space, because the thermal conductivity of commonly said thermal conductive materials such as ordinary aluminum nitride powder thermal conductive silicone is 1.134W / mK, which is much higher than that of air.
[0025] Therefore, when heat is generated at the end of the stator winding, a small part of the heat is dissipated into the internal structure of the motor by thermal radiation, and then the motor fan generates airflow to take the heat out of the motor structure to achieve cooling. Then a large part depends on the heat conductive structure layer in the present invention to conduct heat between solids, and the heat generated at the end of the winding is transferred to the stator core through the heat conductive structure layer for heat dissipation. We can know that the material of the stator core is generally made of silicon steel sheets. It can be seen from the common material thermal conductivity table that the thermal conductivity of silicon steel of a general type is about 52W / mK, which shows that it is a good thermal conductive material, and the turbine loss of the silicon steel sheet is relatively small, so the heat generated at the end of the winding can be more efficiently conducted through the heat conductive structure layer, which can directly reduce the temperature of the end of the winding, and the outer surface of the stator core has a large heat dissipation area, and the fan in the motor can directly generate airflow on the outer surface of the stator core, so that the heat absorbed by the stator core can be convected and exchanged with the outside air, thereby reducing the working temperature of the motor, and thus improving the service life of the motor.
[0026] In this example, see Figure 3 , the heat-conducting structure layer 4 is completely covered on the side surface of the winding end 21 on one side, forming an annular structure sleeved on the winding end and in close contact with the stator core. Because the wiring of the distributed winding is cross-linked, when adding the heat-conducting structure layer, it is necessary to cast or soak the coil close to the winding end, and then fill it to a certain thickness to contact the end face of the stator core to form a circular heat conduction structure to prevent uneven heat conduction and excessive local temperature rise. For another example, in a centralized winding, there is usually one coil per level, so when filling the heat-conducting structure layer, in order to ensure simple construction and close contact and heat conduction between the heat-conducting material layer and the winding end and the stator core, a circular heat-conducting structure layer is more appropriate and reasonable.
[0027] In this example, see Figure 4 The heat-conducting structure layer 4 is in close contact with the stator core 1 and extends along the outer surface of the stator core 1 toward the winding end 21 at the other end. The heat of the stator core 1 is transferred to the heat-conducting structure layer 4 for heat dissipation. Because there are some assembly gaps in the silicon steel sheet, when the heat-conducting structure layer extends to the surface of the silicon steel sheet, it can naturally fill these hot air that is difficult to dissipate heat, and convert the original steady flow of heat radiation into heat conduction on the silicon steel sheet for heat dissipation, thereby improving the heat dissipation efficiency.
[0028] Furthermore, the heat-conducting structure layer 4 is completely coated on the side surface of the winding end 21, and extends along the stator winding 2 to the heat dissipation space in the insulating sleeve 3, and conducts the heat of the stator winding 2 through the heat-conducting structure layer 4. Because the insulating sleeve and the copper wire of the stator winding are not tightly fitted, and there will be a certain gap, when the heat-conducting material layer extends into this heat dissipation space, the copper wire relatively located inside the stator core can also be tightly fitted with the insulating sleeve, thereby achieving a solid heat conduction effect to improve the heat dissipation efficiency, and the heat-conducting structure layer extending into the insulating sleeve is a non-sealed filling structure, leaving a certain heat dissipation space to provide a certain laminar flow space, and a certain heat exchange can be performed in this reserved heat dissipation space after the rotor rotates.
[0029] In this embodiment, the winding ends on both sides are respectively provided with a first heat-conducting structure layer 41 and a second heat-conducting structure layer; the first heat-conducting structure layer 41 is coated on the side surface of the winding end 21 and is in close contact with the stator core 1, and the heat of the stator winding 2 is conducted from the first heat-conducting structure layer 41 to the surface of the stator core for heat dissipation; the second heat-conducting structure layer is filled in the heat dissipation space between the stator winding and the insulating sleeve, and the heat of the stator winding is dissipated by conducting heat through the second heat-conducting structure layer. In specific experiments, it was found that when the winding ends on both sides are filled with heat-conducting material layers for heat transfer to the stator core, two heat flows transmitted in opposite directions will be generated, causing thermal turbulence, and the cooling effect is not as good as that of setting a heat-conducting material layer on one side. Therefore, in order to optimize the heat dissipation effect, the first heat-conducting structural layer is arranged at one end to establish a heat conduction bridge between the winding end and the stator core, and the second heat-conducting structural layer is arranged at the other end to establish heat conduction between the copper wire winding in the insulating sleeve and the inner wall of the stator core; then the heat conduction direction formed by the first heat-conducting structural layer is from the winding end to the surface of the stator core for heat dissipation, and the heat conduction direction formed by the second heat-conducting structural layer is from the copper wire winding in the insulating sleeve to the inner wall of the stator core, and the heat is dissipated by the airflow generated by the rotation of the rotor. The two heat dissipation directions are inconsistent, which will not cause the intersection of heat dissipation paths, and the heat dissipation efficiency will not be reduced due to the guidance and convergence of heat flow.
[0030] As a more optimized solution, the first heat-conducting structure layer 41 is in close contact with the stator core 1 and extends along the outer surface of the stator core toward the other end of the winding. The heat of the stator core is transferred to the first heat-conducting structure layer for heat dissipation. It is worth mentioning that the second heat-conducting structure layer extending into the insulating sleeve is a non-sealed filling structure. The heat of the stator winding is transferred through the second heat-conducting structure layer and heat is dissipated by thermal convection through the heat dissipation space between the stator winding and the insulating sleeve.
[0031] In the above embodiment, the thermally conductive structural layer can be one of the thermally conductive adhesive graphene, thermally conductive silicone grease, thermally conductive paste, heat dissipation paste, and heat dissipation silica gel, or it can be other insulating thermally conductive materials with better effects, such as the nano heat dissipation materials with relatively good effects now; the thermally conductive structural layer is arranged on the side surface of the winding end by filling, and is in close contact with the stator core.
[0032] Example 1
[0033] The Marr wind motor is used as the test motor stator winding, and the centralized winding method is adopted. The motor insulation level is Class B. The test is carried out using the resistance temperature measurement method, and the ambient temperature during the test is 28°C. Two motors are prepared as samples for this experiment and numbered as Motor No. 1 and Motor No. 2. Among them:
[0034] Motor No. 1: It is an unprocessed blank motor without any additional heat dissipation structure;
[0035] Motor No. 2: A treatment motor using a heat-conducting structural layer disposed between the winding end and the stator core;
[0036] The thermal conductive structure layer uses thermal conductive silicone grease, and the test is carried out after the thermal conductive silicone grease is completely cured.
[0037] There are 9 temperature measuring points on both motor No. 1 and No. 2, numbered A, B, C, D, E, F, G, H, and I. On motor No. 1, the winding ends at both ends are respectively provided with A, B, C and D, E, and F, and the temperature measuring points on each side are evenly and equidistantly distributed. On the outer surface of the stator core, and at the midpoint of the stator core busbar, temperature measuring points G, H, and I are evenly and equidistantly distributed on the cylindrical outer surface of the stator core. Similarly, 6 temperature measuring points A-I are also provided at the same position of motor No. 2. The difference is that the three temperature measuring points A, B, and C are distributed on the winding ends covered with a thermal conductive structure layer; the specific experimental data are shown in the following table:
[0038] Table 1
[0039]
[0040] From Table 1, we can know that from the overall temperature measurement point, the winding temperature of the motor stator with a thermal conductive structure layer is lower than that of the stator winding without a thermal conductive structure layer. Among them, the temperature drop at the end of the winding is the most obvious. From the average temperature difference of the AF temperature measurement point, the average temperature drop reaches 10.8℃. Among the nine temperature measurement points, the temperature drop at the AC temperature measurement point is the most obvious, and the maximum cooling effect can reach 15℃. Compared with the winding end with a thermal conductive structure layer, the cooling effect is obviously better. We can clearly see from the experimental data that the thermal conductive structure layer at the winding end undertakes most of the heat conduction channel, which provides the most efficient heat dissipation effect on one side.
[0041] Example 2
[0042] The Wenzhou Weipu motor is used as the stator winding of the test motor, and the distributed winding method is adopted. The motor insulation level is Class E. The test is carried out by directly applying voltage to the stator winding, and two motors are prepared as samples for this experiment, and are numbered as Motor No. 1 and Motor No. 2. The test time is 120 minutes, of which:
[0043] Motor No. 1: It is an unprocessed blank motor without any additional heat dissipation structure;
[0044] Motor No. 2: a treatment motor using a heat-conducting structural layer disposed between the winding end and the stator core;
[0045] There are 4 temperature measuring points on both motor No. 1 and motor No. 2, numbered A, B, C, and D. On motor No. 1, A and B are set at the end of the winding on one side, and the temperature measuring points are evenly distributed at equal intervals; on the outer surface of the stator core, temperature measuring points C and D are set at the midpoint of the stator core busbar, and temperature measuring points C and D are evenly distributed on the cylindrical outer surface of the stator core. Similarly, a total of 4 temperature measuring points AD are set at the same position of motor No. 2. The difference is that the two temperature measuring points A and B are distributed on the end of the winding covered with a thermal conductive structure layer; and five groups of loading voltages are set for comparison. The specific experimental data are shown in the following table:
[0046] Table 2
[0047]
[0048] From Table 2, we can know that from the overall temperature measurement points, the winding temperature of the motor stator with a thermal conductive structure layer is lower than that of the stator winding without a thermal conductive structure layer. Among them, the temperature drop at the winding end is the most obvious. From the average temperature difference of the AD temperature measurement points, the average temperature drop reaches 14.94℃. The temperature drop of these four temperature measurement points can reach a maximum cooling effect of 16.5℃. For the winding end with a thermal conductive structure layer, the cooling effect is obviously better. We can clearly see from the experimental data that the thermal conductive structure layer at the winding end undertakes most of the heat conduction channel and provides a better heat dissipation solution.
[0049] The advantages of the present invention are:
[0050] 1) The existing motor heat dissipation structure is complex and the heat dissipation efficiency is not high. The present invention creatively uses heat-conducting materials to bridge the winding end and the stator core, so that the heat conduction direction is changed to the winding end to the stator core for heat dissipation, which greatly improves the heat dissipation efficiency;
[0051] 2) The overall assembly structure of the motor has not changed, so there will be no additional restrictions on the existing use environment, and the cooling efficiency can reach about 15°C, greatly improving the service life of the motor.
[0052] The above disclosures are only several specific embodiments of the present invention, but the present invention is not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A heat dissipation structure of a motor stator winding, comprising a stator core and a stator winding wound on the stator core, an insulating sleeve is arranged between the stator winding and the stator core, characterized in that: Both ends of the stator winding extending out of the stator core form winding ends, and a heat-conducting structural layer is provided between the winding ends and the stator core; The winding ends on both sides are respectively provided with a first heat-conducting structure layer and a second heat-conducting structure layer; the first heat-conducting structure layer is coated on the side surface of the winding end and is in close contact with the stator core, and the heat of the stator winding is conducted from the first heat-conducting structure layer to the surface of the stator core for heat dissipation; the second heat-conducting structure layer is filled in the heat dissipation space between the stator winding and the insulating sleeve, and the heat of the stator winding is dissipated by conducting heat through the second heat-conducting structure layer; Wherein, the first heat-conducting structure layer extends along the outer surface of the stator core toward the winding end at the other end, and the heat of the stator core is conducted to the first heat-conducting structure layer for heat dissipation; The second heat-conducting structure layer extending into the insulating sleeve is a non-sealed filling structure, and the heat of the stator winding is conducted through the second heat-conducting structure layer, and heat is dissipated by heat convection through the heat dissipation space between the stator winding and the insulating sleeve; The heat conduction direction formed by the first heat-conducting structure layer is from the end of the winding to the surface of the stator core for heat dissipation, while the heat conduction direction formed by the second heat-conducting structure layer is from the copper wire winding in the insulating sleeve to the inner wall of the stator core, and the heat is dissipated by the airflow generated by the rotation of the rotor, so that the two heat dissipation directions are inconsistent; The first heat-conducting structure layer is arranged at one end to establish a heat conduction bridge between the winding end and the stator core, and the second heat-conducting structure layer is arranged at the winding end at the other end.
2. The heat dissipation structure of the motor stator winding according to claim 1, characterized in that: The thermally conductive structural layer is one of thermally conductive adhesive graphene, thermally conductive silicone grease, thermally conductive paste, heat dissipating paste, and heat dissipating silica gel.
3. The heat dissipation structure of the motor stator winding according to claim 2, characterized in that: The heat-conducting structural layer is arranged on the side surface of the stator winding by filling, and is in close contact with the stator core.