Iron core assembly annealing method and tool

Abstract

The invention discloses an annealing method and tool for an iron core assembly, and belongs to the technical field of motor iron core machining, and the annealing method comprises the following steps: laminating and positioning a plurality of silicon steel sheets one by one, maintaining the pressure after laminating and assembling, and then welding and fixing to form the iron core assembly; putting the iron core assembly into a vacuum container, vacuumizing and heating the iron core assembly; after the temperature of the iron core assembly reaches the preset temperature, heat preservation is conducted for a period of preset time; and after heat preservation is finished and the temperature is reduced by 45%-50%, the vacuum container is opened, and then the iron core assembly is naturally cooled to the room temperature. The tool comprises at least two assemblies, the assemblies are in an arc shape, the inner sides of the assemblies are matched with the circumferential outer wall of the iron core assembly, and the multiple assemblies can be spliced end to end to form a barrel so as to restrain the circumferential direction of the iron core assembly; and the locking piece is used for locking and fixing the adjacent combined pieces. According to the invention, mechanical and thermal stress can be effectively eliminated, the iron loss is reduced from the overall structure, and the motor efficiency is improved when the overall structure is applied.

Description

Technical Field

[0001] The present application belongs to the technical field of motor core processing, and in particular, relates to a core assembly annealing method and tooling. Background Art

[0002] The efficiency of the motor system directly affects the comprehensive endurance of the vehicle. Among them, the factors that affect the motor efficiency are mainly copper loss, iron loss, mechanical loss, and oil stirring loss. The iron loss of the motor accounts for 30%-60% of the total loss. Under different application conditions, the loss ratio varies. There are many factors that affect the iron loss of the motor. The characteristics of the silicon steel sheet raw material itself determine the difference in iron loss. Therefore, annealing treatment is required. After secondary molding and high-temperature annealing, mechanical and thermal stresses can be effectively eliminated, iron loss can be reduced, and motor efficiency and vehicle endurance can be improved.

[0003] In the prior art, similar solutions for annealing the core assembly or silicon steel sheets are mainly to anneal the raw material steel coils and the single silicon steel sheets after stamping. However, annealing the single silicon steel sheet cannot effectively solve the iron loss problem of the core assembly, and the prior art does not consider the iron loss problem of the core assembly. In the actual application of silicon steel sheets, most core assemblies are fixed into one piece by laser welding, and the mechanical extrusion internal stress after lamination affects the iron loss. Summary of the invention

[0004] The present application aims to solve the technical problem of iron loss of the core assembly at least to a certain extent. To this end, the present application provides a core assembly annealing method and tooling, which can effectively eliminate mechanical and thermal stresses, reduce iron loss from the overall structure, and thereby improve motor efficiency when the overall structure is used.

[0005] In a first aspect, an embodiment of the present application provides a core assembly annealing method, which includes:

[0006] Multiple silicon steel sheets are stacked and positioned one by one, and after stacking and assembling, the pressure is maintained, and then welded and fixed to form an iron core assembly;

[0007] The core assembly is placed in a vacuum container, vacuumed and heated; after the temperature of the core assembly reaches a preset temperature, it is kept warm for a preset time;

[0008] After the insulation is completed, when the temperature drops by 45% to 50%, the vacuum container is opened and the core assembly is allowed to cool naturally to room temperature.

[0009] In some embodiments, the preset temperature is [400° C., 420° C.].

[0010] In some embodiments, the preset time is [45 min, 65 min].

[0011] In some embodiments, when heating the core assembly, electric heating is used, and the heating time and the temperature in the vacuum container are regularly recorded during the heating process until the temperature reaches a preset temperature.

[0012] In some embodiments, during the heating process, a protective gas is introduced into the vacuum container, and after the insulation is completed, the introduction of the protective gas is stopped.

[0013] In some embodiments, during pressure maintenance, a pressure maintenance force is applied to the end surfaces of the multiple silicon steel sheets assembled in a stacked manner, so that the multiple silicon steel sheets are subjected to force in the stacking direction, and the pressure maintenance force is [1.8Mpa, 2.2Mpa].

[0014] In some embodiments, when welding and fixing, diagonal welding is performed on the welding gaps to be welded formed by the welding notches on the outer edges of the multiple silicon steel sheets assembled in a stacked manner.

[0015] In some embodiments, before placing the core assembly into the vacuum container, the core assembly is first constrained and fixed in the circumferential direction, so that during the subsequent heating, insulation and cooling processes, the core assembly is always subject to the peripheral constraint force.

[0016] In a second aspect, an embodiment of the present application provides a core assembly annealing tool, which is applied to the above-mentioned core assembly annealing method and is used to assemble and fix the core assembly before the core assembly is placed in a vacuum container. The tool includes:

[0017] At least two assemblies, the assemblies are arc-shaped, the inner side of the assemblies matches the circumferential outer wall of the core assembly, and multiple assemblies can be spliced ​​end to end to form a cylinder to constrain the circumference of the core assembly;

[0018] The locking piece is used to lock and fix adjacent components when assembling and fixing them with the core assembly.

[0019] In some embodiments, a stop step consistent with the arc shape is convexly provided on the inner side of the end of the assembly, which is used to support the core assembly when assembled and fixed with the core assembly.

[0020] It can be seen from the above technical solution that the beneficial effects of this application are:

[0021] 1. The present application forms a preliminary overall structure by stacking and assembling, and reduces the influence of iron loss caused by adjacent silicon steel sheets in the welding process by maintaining pressure and then welding. After the silicon steel sheets are stacked together, they are welded together after local high-temperature hot melting, condensation and solidification. High temperature and thermal stress will be generated locally during the welding process, and iron loss is also likely to occur. Then, the core assembly is placed in a vacuum container and heated to a preset temperature to make the internal structure of the core assembly tend to be uniform, and the internal thermal stress and organizational stress are eliminated. By keeping warm for a preset period of time, it helps to make the internal grains more uniform and reduce the performance difference caused by uneven distribution. Finally, by first cooling by 45% to 50% and then cooling naturally, the deformation of the core assembly or surface cracking caused by excessive cooling is avoided, and the internal structures of the core assembly are ensured to be stable, thereby reducing iron loss during use. Therefore, the present application can effectively eliminate mechanical and thermal stresses, reduce iron loss from the overall structure, and thus improve the efficiency of the motor when the overall structure is used.

[0022] 2. The present application takes into account the iron loss generated by the assembly and use of the core assembly and the motor housing, and uses tooling for simulation. A cylinder that can match the circumferential outer wall of the core assembly is formed by the assembly, and then locked and fixed by locking members to form a constraint on the core assembly. The constraint on the inner side of the assembly is used to simulate the constrained state of the core assembly during use. Heating and annealing are performed in this state, which can be closer to the actual use conditions of the core assembly, and can further remove more internal stress, thereby reducing iron losses and maintaining the working efficiency of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced one by one below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other embodiments and drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of an embodiment of the core assembly of the present invention is shown;

[0025] Figure 2 A schematic diagram showing the steps of an embodiment of the iron core assembly annealing method of the present invention is shown;

[0026] Figure 3 A schematic diagram showing the steps of another embodiment of the core assembly annealing method of the present invention is shown;

[0027] Figure 4 A curve relationship diagram showing the iron loss and the holding time of the iron core assembly of the present invention is shown;

[0028] Figure 5A curve relationship diagram showing the magnetic induction and the holding time of the core assembly of the present invention is shown;

[0029] Figure 6 A schematic diagram of an embodiment of a constrained core assembly of the present invention is shown;

[0030] Figure 7 A schematic diagram of an embodiment of the assembly of the iron core assembly and the motor housing of the present invention is shown;

[0031] Figure 8 A schematic diagram of an embodiment of an annealing tool of the present invention is shown;

[0032] Fig. 9 A schematic diagram of an embodiment of the assembly and the locking member of the present invention is shown;

[0033] Fig.10 A schematic diagram of an embodiment of the core assembly of the present invention is shown;

[0034] Figure numerals: 100, iron core assembly; 110, silicon steel sheet; 200, annealing tool; 210, assembly; 211, stop step; 220, locking piece; 300, motor housing. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that all directional indications in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] The present application is described below with reference to the accompanying drawings and specific embodiments:

[0040] Please refer to Figure 1 and Figure 2 In the first aspect of the present application, an embodiment provides an annealing method for a core assembly. The core assembly 100 is formed by laminating and welding hundreds of silicon steel sheets 110 with a thickness of 0.1 mm to 0.5 mm, such as 0.25 mm in thickness. The annealing method comprises the following steps:

[0041] S1. Stack and position multiple silicon steel sheets 110 one by one. The silicon steel sheets 110 are thin sheet structures that have been stamped. The outer edges of the silicon steel sheets 110 are provided with multiple welding notches and stacking positioning notches. When stacking, the welding notches of each silicon steel sheet 110 in the core assembly 100 are aligned, and the stacking positioning notches are used to position each silicon steel sheet 110 in the overall structure, so that the assembly efficiency of the core assembly 100 is higher and more accurate. After stacking and assembling, pressure is maintained, and a holding pressure is applied to the upper surface of the stacked overall structure, and then each silicon steel sheet 110 is welded and fixed as a whole through the welding notches to form the core assembly 100. In an optional embodiment, before the core assembly 100 is placed in a vacuum container, the surface of the core assembly 100 is first cleaned. An air gun can be used to clean the surface of the core assembly 100 to ensure that there are no impurities on the surface of the core assembly 100.

[0042] S2. The core assembly 100 is heated and annealed. The core assembly 100 is first placed in a vacuum container. If a vacuum cover is used as the vacuum container, the vacuum cover is connected to a vacuum pump through a pipeline. The vacuum container can be evacuated by starting the vacuum pump. After the vacuum cover is closed, the vacuum container is evacuated to a vacuum state inside the vacuum container, and the core assembly 100 is heated. A heating device, such as an electric heating element, is placed in the vacuum container. For example, a resistor for heating is placed in the vacuum container. The core assembly 100 can be heated after power is turned on. After the temperature of the core assembly 100 reaches a preset temperature, it is kept warm for a preset time. The preset temperature and the preset time are both temperature and time values ​​that are pre-calculated and set before the annealing operation.

[0043] S3, cool and shape the core assembly 100. After the insulation is completed, when the temperature drops by 45% to 50%, such as from 400°C to 200°C, open the vacuum container, and then let the core assembly 100 cool naturally to room temperature. In the natural state, the core assembly 100 gradually cools from the temperature after the initial cooling to room temperature to avoid deformation or surface cracking of the core assembly 100 caused by too fast cooling. After the cooling is completed, the core assembly 100 is taken out for standby for motor assembly. After the core assembly 100 is annealed and formed, it will be used for the assembly of the stator assembly of the electric drive system. It is necessary to complete the insulating paper, copper wire, varnishing, coating, copper wire welding and other processes on the workbench. By welding and fixing the core assembly 100, compared with the existing processing of raw materials, each silicon steel sheet 110 constituting the core assembly 100 is in a certain constraint state under the action of the welding point. This method can release the internal mechanical stress and thermal stress to a certain extent during high-temperature annealing, which helps to reduce iron loss.

[0044] The annealing scheme of the prior art is to anneal the raw material steel coil or the single silicon steel sheet 110 to reduce the iron loss by annealing, but there is no annealing scheme for the core assembly 100. The iron loss of the core assembly 100 must be considered because the damage to the raw materials during the processing and manufacturing process further increases the iron loss. For example, when the silicon steel sheets 110 are stacked and fixed, local mechanical shear, local high temperature, mechanical extrusion, etc. occur, which will cause the internal stress of the silicon steel sheet 110 to be unable to be released, causing the crystal phase organization direction to shift, and ultimately leading to the intensification of the local eddy current effect of the silicon steel sheet 110, increased iron loss, and severe heat generation, thereby reducing the working efficiency of the motor. The present application forms a preliminary overall structure through stacking and assembly, and reduces the influence of iron loss caused by adjacent silicon steel sheets 110 in the welding process by maintaining pressure and then welding. After the silicon steel sheets 110 are stacked together, they are welded together after local high-temperature hot melting, condensation and solidification. High temperature and thermal stress will be generated locally during the welding process, and iron loss is also likely to occur. Then, the core assembly 100 is placed in a vacuum container and heated to a preset temperature to make the internal structure of the core assembly 100 tend to be uniform, eliminate internal thermal stress and organizational stress, and keep warm for a preset period of time to help the internal grains more uniform and reduce performance differences caused by uneven distribution. Finally, by first cooling 45% to 50% and then cooling naturally, deformation or surface cracking of the core assembly 100 caused by excessive cooling is avoided, ensuring that the internal structures of the core assembly 100 tend to be stable, thereby reducing iron loss during use. Therefore, the present application can effectively eliminate mechanical and thermal stresses, reduce iron loss from the overall structure, and thus improve motor efficiency when the overall structure is used.

[0045] Please refer to Figure 3In some embodiments, in step S2, the preset temperature is [400°C, 420°C], that is, when the core assembly 100 is heated, the temperature is heated to 400°C, 410°C or 420°C to ensure the ambient temperature in the vacuum container. In order to more accurately control the temperature, a temperature sensor can be added to the vacuum container. The temperature sensor is electrically connected to the controller of the heating device. The power of the heating device is adjusted by the numerical feedback of the temperature detection, so as to maintain the heating temperature near the preset temperature. In some embodiments, the preset time is [45min, 65min]. After the core assembly 100 is heated to the preset temperature, it is kept warm for a period of time. The warm-keeping time is controlled at 45min, 55min or 65min. The warm-keeping stage is maintained for a period of time to ensure that the core assembly 100 is kept in a stable temperature environment, so that the core assembly 100 reaches a uniformly heated state, which helps to eliminate the internal stress in the core assembly 100, stabilize the structure and reduce deformation.

[0046] Please refer to Figure 4 and Figure 5 The heating temperature of the core assembly 100 is maintained at 400℃~420℃, and the holding time has an impact on the iron loss and magnetic properties, and also has an impact on the production cycle; in the early stage of the annealing process, the temperature at which the core assembly 100 should be maintained for insulation and the best insulation time are tested and studied. The statistical comparison of the two indicators of iron loss and magnetic induction of the core assembly 100 is as follows Figure 4 and Figure 5 As shown in the curve.

[0047] Taking the test data of the iron loss P1.0 / 400 and the magnetic induction B5000 of the core assembly 100 as an example, the heating temperatures maintained at 380°C, 400°C, 420°C, and 440°C are compared; and the insulation times of 5min, 10min, ..., 80min are compared.

[0048] Comparison of the effects of high temperature annealing maintenance temperature and holding time on iron loss and magnetic induction, the preliminary conclusions are as follows:

[0049] (1) From the comparison of the iron loss P1.0 / 400 curve of the core assembly 100, the loss when the heating temperature is 400℃ and 420℃ is lower, and the effect is better, which is beneficial to reduce iron loss and improve motor efficiency.

[0050] (2) From the comparison of the magnetic induction B5000 curve of the core assembly 100, it can be seen that with the increase of the insulation time, the magnetic induction gradually increases, which has a certain improvement on the performance of the motor; from 45 minutes to 80 minutes of insulation, the speed of magnetic induction enhancement slows down and tends to be stable. Considering the production cycle, it is recommended that the insulation time be maintained at 45-65 minutes.

[0051] It should be noted that when B5000 describes the magnetic induction intensity, B5000 ≥ 1.5T. Here, the number 5000 actually refers to a specific magnetic field strength condition, under which the magnetic flux reaches 1.5 Tesla. The magnitude of the magnetic flux will vary with the change of the magnetic field strength. Therefore, under different magnetic field strengths, the corresponding magnetic flux will also vary. Simply put, 5000 is a specific magnetic field strength value, which is associated with a magnetic flux of 1.5 Tesla. Iron loss P1.0 / 400 refers to the iron loss when the magnetic polarization intensity is 1.0T at a frequency of 400Hz. Iron loss is a measure of the energy loss of ferromagnetic materials in an alternating magnetic field due to hysteresis, eddy currents and residual losses. Specifically, P1.0 / 400 represents the energy lost per unit mass of ferromagnetic material in one cycle under the conditions of a frequency of 400Hz and a magnetic polarization intensity of 1.0T.

[0052] In some embodiments, in step S2, when heating the core assembly 100, electric heating is used, and the heating time and the temperature in the vacuum container are regularly recorded during the heating process until the temperature reaches the preset temperature. The electric heating method combined with the sensor can control the temperature more accurately. The electric heating can use an electric heating element. During the heating process of the core assembly 100, the heating time and the ambient temperature in the vacuum container are recorded every 15 minutes. In some embodiments, the atmosphere around the core assembly 100 needs to be controlled during the heating process. During the heating process, a protective gas is introduced into the vacuum container. The protective gas can be a hydrogen-nitrogen atmosphere. When the hydrogen-nitrogen atmosphere is introduced, the temperature is 20 mg / m 3 According to the standard, 75% hydrogen and 25% nitrogen are introduced. After the insulation time is up, the insulation ends and the introduction of hydrogen and nitrogen atmosphere is stopped; the purpose of the protective gas is to protect the surface of the core assembly 100, prevent oxidation and carburization, and maintain the integrity of the surface insulation coating of the core assembly 100.

[0053] In some embodiments, during the pressure maintaining in step S1, the pressure maintaining is applied to the end faces of the multiple silicon steel sheets 110 that are stacked and assembled, such as applying the pressure maintaining on the upper surfaces of the multiple silicon steel sheets 110 that are stacked and assembled, so that the multiple silicon steel sheets 110 are subjected to force in the stacking direction, and the pressure maintaining is [1.8Mpa, 2.2Mpa], such as 1.8Mpa, 2.0Mpa or 2.2Mpa. The pressure maintaining can reduce the air gap between adjacent silicon steel sheets 110, make the adjacent silicon steel sheets 110 closer, make the internal stress distribution of the core assembly 100 uniform, and also help to reduce magnetic energy loss, reduce noise and eddy current loss, and thus improve the performance of the core assembly 100. In some embodiments, when the overall structure of the multiple silicon steel sheets 110 is welded and fixed, the gaps to be welded formed by the welding notches on the outer edges of the multiple silicon steel sheets 110 that are stacked and assembled are diagonally welded. Since the multiple silicon steel sheets 110 have multiple welding notches, the core assembly 100 also forms multiple gaps to be welded around it. During welding, the silicon steel sheets 110 are welded at the gaps to be welded to form the core assembly 100.

[0054] Please refer to Figure 6 and Figure 7 In some embodiments, before the core assembly 100 is placed in the vacuum container, the core assembly 100 is first constrained and fixed in the circumferential direction. The circumferential outer side of the core assembly 100 can be constrained by a tool or other means. The tool adopts a cylindrical structure, and the inner side of the cylindrical structure is close to the circumferential outer side of the core assembly 100 to constrain it, so that the core assembly 100 is always subject to the peripheral constraint force during the subsequent heating, insulation and cooling process. By constraining and fixing the core assembly 100 in the circumferential direction, it is possible to simulate the constraint force of the motor housing 300 on the core assembly 100 during use, and the internal stress during use can be eliminated, thereby reducing iron loss; at the same time, annealing in a free state may cause deformation of the key structural features of the core tooth slot, deterioration of the cylindricality of the inner and outer diameters, and desoldering of the solder joints. Due to the use of a method to constrain the core assembly 100, after high-temperature heating, insulation and cooling, the coaxiality of the silicon steel sheet 110 in the existing core assembly 100, deformation of the tooth features and desoldering are avoided.

[0055] Please refer to Figure 8In a second aspect of the present application, an embodiment provides a core assembly annealing tool, which is applied to the above-mentioned core assembly annealing method. Before the core assembly 100 is placed in a vacuum container, the tool is used to assemble and fix the core assembly 100. The tool includes: at least two assemblies 210 and a locking member 220. The number of assemblies 210 can be two, three or other numbers. The assembly 210 is arc-shaped, and the arc matches the core assembly 100. Specifically, the inner side of the assembly 210 matches the circumferential outer wall of the core assembly 100. Multiple assemblies 210 can be spliced ​​end to end to form a cylinder. For example, two assemblies 210 are used. There are assemblies 210, each of which is semicircular and clamping. The assemblies 210 are made of 45# steel, and ears are extended outward on both sides. The ears are provided with multiple locking holes. When the two assemblies 210 are butt-jointed, the ears of the assemblies 210 are just opposite to each other, and the locking holes are opposite to each other. The inner side of the assembly 210 is tightly attached to the outer periphery of the core assembly 100 to form a sleeve structure, so as to constrain the circumference of the core assembly 100. The annealing fixture 200 is interference fit with the core assembly 100, and the interference design is consistent with the core assembly 100 in the actual motor housing 300 to simulate the actual constraint situation. For example, two assemblies 210 are symmetrically arranged, and the semicircular arcs of the two assemblies 210 are spliced ​​into a perfect circle. The locking member 220 is used to lock and fix the adjacent assemblies 210 when assembling and fixing with the core assembly 100. The locking member 220 is a bolt. After the two assemblies 210 are spliced, the bolts are passed through the locking holes to fix the two assemblies 210. In an optional embodiment, the inner side of the end of the assembly 210 is convexly provided with a stop step 211 consistent with the arc shape, such as Fig. 9 A stop step 211 is provided on the inner side of the bottom of the middle assembly 210 . The stop step 211 is arc-shaped and convexly formed along the inner side of the assembly 210 . The stop step 211 is used to support the core assembly 100 when assembled and fixed with the core assembly 100 .

[0056] In the general annealing method, the iron core assembly 100 is heated and annealed in a free state, so that the effect of annealing to eliminate internal stress can be achieved. Considering that the actual iron core assembly 100 will be interference-fitted with the motor housing 300, mechanical stress after matching will be generated, which increases iron loss. Therefore, the present application uses an annealing tool 200 to fix the iron core assembly 100 in a free state with an interference fit, simulates the iron core assembly 100 to perform high-temperature annealing under the constraint state of interference fit with the motor housing 300, and restores the stress state of the final iron core assembly 100 assembled in the motor housing 300, which can further enhance annealing to remove more internal stress and further reduce iron loss. At the same time, it ensures the accurate insertion of the copper wire in the subsequent stator core slot, avoids scratching of the enameled wire, and the coaxiality accuracy of the stator assembly and the housing is higher. In actual use, the annealing tool 200 of the present application is not only applicable to the iron core assembly 100 fixed by welding the silicon steel sheet 110, but also applicable to the iron core assembly 100 with axial penetration bolts tightening and restraining; Fig.10 As shown, for other core assemblies 100 with non-full-circular regular structures, such as core assemblies 100 with through-hole ear fixing designs, the tooling can be modified and adjusted to adapt for use, and the principle of constrained annealing is similar.

[0057] The annealing scheme of the prior art is to anneal the raw material steel coil or the single silicon steel sheet 110 to reduce the iron loss by annealing, but there is no annealing scheme for the core assembly 100. The iron loss of the core assembly 100 must be considered. When the core assembly 100 is assembled into the motor housing 300 for use, the core assembly 100 and the motor housing 300 have an interference fit, and the extrusion pressure is large, which causes mechanical stress, increases the iron loss of the core assembly 100, and reduces the working efficiency of the motor. The present application takes into account the iron loss generated by the assembly and use of the core assembly 100 and the motor housing 300, and uses tooling for simulation. A cylindrical body that can match the circumferential outer wall of the core assembly 100 is formed by the assembly 210, and then locked and fixed by the locking piece 220 to form a constraint on the core assembly 100. The constraint on the inner side of the assembly 210 is used to simulate the constrained state of the core assembly 100 during use. Heating and annealing are performed in this state, which can be closer to the actual use condition of the core assembly 100, and can further remove more internal stress, thereby reducing iron loss, thereby maintaining the working efficiency of the motor.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", "optional example" or "optional implementation" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0059] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0060] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A core assembly annealing method, characterized in that: include: Stacking and positioning a plurality of silicon steel sheets (110) one by one, maintaining the pressure after stacking and assembling, and then welding and fixing to form an iron core assembly (100); The iron core assembly (100) is placed in a vacuum container, vacuumized, and the iron core assembly (100) is heated; after the temperature of the iron core assembly (100) reaches a preset temperature, the temperature is kept constant for a preset time; After the heat preservation is completed, when the temperature drops by 45% to 50%, the vacuum container is opened, and the iron core assembly (100) is allowed to cool naturally to room temperature.

2. The core assembly annealing method according to claim 1, characterized in that: The preset temperature is [400°C, 420°C].

3. The core assembly annealing method according to claim 2, characterized in that: The preset time is [45min, 65min].

4. The core assembly annealing method according to claim 2, characterized in that: When the iron core assembly (100) is heated, electric heating is adopted, and during the heating process, the heating time and the temperature in the vacuum container are regularly recorded until the temperature reaches the preset temperature.

5. The core assembly annealing method according to claim 1, characterized in that: During the heating process, a protective gas is introduced into the vacuum container, and after the heat preservation is completed, the introduction of the protective gas is stopped.

6. The core assembly annealing method according to claim 1, characterized in that: During the pressure maintenance, a pressure maintenance force is applied to the end faces of the multiple silicon steel sheets (110) assembled in a stacked manner, so that the multiple silicon steel sheets (110) are subjected to force in the stacking direction, and the pressure maintenance force is [1.8Mpa, 2.2Mpa].

7. The core assembly annealing method according to claim 6, characterized in that: During the welding and fixing, diagonal welding is performed on the weld gaps to be welded formed by the welding notches on the outer edges of the multiple silicon steel sheets (110) assembled in a stacked manner.

8. The core assembly annealing method according to any one of claims 1 to 7, characterized in that: Before placing the iron core assembly (100) into the vacuum container, the iron core assembly (100) is first constrained and fixed in the circumferential direction, so that during the subsequent heating, heat preservation and cooling processes, the iron core assembly (100) is always subject to the constraining force of the outer circumference.

9. A core assembly annealing tool, characterized in that: Applicable to the iron core assembly (100) annealing method according to claims 1 to 8, before the iron core assembly (100) is placed in a vacuum container, the tooling is used to assemble and fix with the iron core assembly (100), the tooling comprising: at least two assemblies (210), the assemblies (210) being arc-shaped, the inner side of the assemblies (210) matching the circumferential outer wall of the core assembly (100), and a plurality of the assemblies (210) being able to be spliced ​​end to end to form a cylinder to constrain the circumference of the core assembly (100); The locking member (220) is used to lock and fix the adjacent assembly (210) when being assembled and fixed with the iron core assembly (100).

10. The core assembly annealing tool according to claim 9, characterized in that: A stop step (211) that is consistent with the arc shape is convexly provided on the inner side of the end of the assembly (210) and is used to support the iron core assembly (100) when being assembled and fixed with the iron core assembly (100).

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