A bonding-welding-combined connecting process for a stator core

Abstract

The application discloses a kind of bonding welding composite connection process of stator core.The application is improved to normal temperature viscose, with the conforming process of end welding by the secondary heating solidification in traditional process, compared with traditional pure bonding or pure welding scheme, this scheme is superior to pure welding scheme in keeping low iron loss characteristics, it is superior to pure bonding scheme in structural strength, realizes the synergistic effect of bonding magnetic, welding firm;Specifically, by dispensing filling to annular dispersion piece group two ends, complete piece-to-piece insulation sealing and preliminary fixation under normal temperature without heating condition, avoid the iron loss rise caused by high temperature thermal stress;At the same time, the insulation bonding layer formed after normal temperature solidification can effectively cut off the eddy current path between silicon steel strip, so that interlayer resistance is significantly higher than pure welding stator, reduce core eddy current loss, limit heat affected zone in the shallow area of outer peripheral sidewall, effectively protect the magnetic properties of stator core internal silicon steel strip from high temperature damage.

Description

Technical Field

[0001] This invention specifically relates to a composite bonding and welding process for stator cores. Background Technology

[0002] The stator core is the core component of an electric motor. In its manufacturing process, hundreds of silicon steel sheets need to be firmly stacked into a whole. As the drive motors of new energy vehicles develop towards higher speeds, Shougang's 20SW1200 grade is mainly designed for the needs of high-speed motor development. With its low loss and high strength characteristics, it will empower new energy vehicles with greater horsepower, higher efficiency, and longer range. It is an ideal base material for the next generation of high-efficiency motor cores. In order to reduce eddy current losses, silicon steel sheets are usually made into thin sheets for assembly. This brings assembly challenges, namely, how to firmly stack hundreds or even thousands of thin silicon steel sheets into a stable core.

[0003] Currently, when using ultra-thin high-grade silicon steel sheets such as 20SW1200 to manufacture motor cores, traditional connection processes often employ "pure bonding" or "welding first and then strengthening" methods in the stacking connection stage.

[0004] Among them: the high temperature during welding causes the insulating coating of silicon steel sheet to be pyrolyzed and destroyed, and the circuit conduction formed at the welding point will also generate eddy current loss. In addition, welding will also introduce residual stress, leading to an increase in iron loss, which will seriously weaken the original excellent low iron loss characteristics of high-grade materials.

[0005] Although the bonding method causes the least damage to magnetic properties, the current bonding technology has the risk of adhesion degradation or even mechanical failure under high temperature and cyclic load conditions during motor operation. In addition, the manufacturing efficiency is low, and the iron core is prone to breakage and cracking after production, resulting in insufficient strength of pure bonding process.

[0006] It is evident that traditional connection methods fail to achieve optimal coupling between adhesive and welding effects, lacking end-temperature adhesive bonding and overall welding composite technology. They cannot achieve the synergistic advantages of the two processes through adhesive magnetic preservation and welding reinforcement, and thus cannot meet the needs of mass production and stable operation of the new generation of high-efficiency motors.

[0007] Therefore, it is necessary to invent a composite bonding and welding process for stator cores to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to provide a composite bonding and welding process for stator cores. By improving the secondary heating and curing process in the traditional process to a process of room temperature bonding and end welding, this solution is superior to the pure welding solution in maintaining low iron loss characteristics and superior to the pure bonding solution in terms of structural strength compared to the traditional pure bonding or pure welding solutions. It achieves a synergistic effect of bonding for magnetic preservation and welding for strong reinforcement, thereby solving the above-mentioned shortcomings in the technology.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a composite bonding and welding process for stator cores, comprising the following steps:

[0010] Step 1: Punch the silicon steel strip into stator laminations and stack them to form an annular lamination group;

[0011] Step 2: Spray a layer of curing agent onto both ends of the annular loose piece group through the dispensing tray, then apply glue to the curing agent coating, and press the stator loose pieces together to bond them into a stator core prototype.

[0012] Step 3: Leave a fine gap between the laminations at the intervals of the insulating adhesive layer, and weld the ends of the stator core prototype as a whole to obtain the stator core;

[0013] Step 4: Integrate the pressing, dispensing, and welding processes to form a complete, automated stator core composite curing production line with fully adjustable parameters.

[0014] Step 5: Establish a performance testing and evaluation system to test and evaluate the performance of stator cores produced on the stator core composite curing production line.

[0015] In the aforementioned composite bonding and welding process for the stator core, in step 1, the silicon steel strip is set as cold-rolled non-oriented silicon steel strip 20SW1200 with a thickness of 0.20mm; the stacking method of the silicon steel strip is: self-locking riveting or stacking riveting.

[0016] In the aforementioned composite bonding process of stator core, in step 2, the stator segments are positioned by external tooling during adhesive application, and are pressed together after the adhesive has penetrated into the fine gaps between the stator segments. The adhesive is Pared anaerobic adhesive, and the curing agent is Pared curing agent. The adhesive and curing agent are mixed in a 1:1 ratio, and the curing time is 60 seconds. After the adhesive is cured, an insulating bonding layer is formed, and the curing of the adhesive is indicated by the segmented stator core prototype being in a hardened and non-dispersed state.

[0017] In the aforementioned composite bonding and welding process for the stator core, step 2 involves applying adhesive to the curing agent coating. The specific process is as follows:

[0018] The adhesive is applied to the inner and outer rings of the annular lamination group, with the center of the ring as the reference, and the adhesive is applied circumferentially to the teeth and yokes on both ends of the stator core prototype.

[0019] After dispensing the adhesive, spread it evenly on the loose sheet to present the predetermined shape, requiring no accumulation, no shrinkage, and no unevenness;

[0020] The number of adhesive dots in the inner ring (i.e., the stator slot) must be at least 54, the number of adhesive dots in the outer ring must be at least 54, the number of consecutive empty adhesive dots must be at most 3, the adhesive dots in the inner and outer rings corresponding to the teeth and yoke must not be empty at the same time, that is, at least 1 effective adhesive dot must be reserved in the stator slot between every two loose pieces, and the adhesive dots of a single piece must show good granular shape.

[0021] In the aforementioned bonding and welding composite connection process of the stator core, in step 2, the glue dispensing temperature is set to 20-30℃, the humidity is ≤65%, and the single-section finished product is sprayed with stamping oil once for every 10 pieces. When the glue and curing agent are not used, they are stored in a refrigerator, and the refrigerator temperature is controlled at 2℃-8℃.

[0022] In the aforementioned composite bonding and welding process for the stator core, step 3 involves integral welding of the end of the stator core prototype. Specifically, laser welding is performed sequentially along the outer peripheral sidewall of the stator core prototype to reinforce the end of the stator core prototype.

[0023] In the aforementioned composite bonding and welding process for stator cores, in step 3, the weld width is 1-2 mm, the weld penetration is 0.6-1.5 mm, and the weld plane protrusion is less than 0.3 mm.

[0024] In the aforementioned composite bonding and welding process for the stator core, step 5 includes a performance testing and evaluation system that comprehensively tests the flatness, parallelism, and perpendicularity of the stator core.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] In the production of stator cores, this invention first applies adhesive at room temperature to bond the stator laminations, achieving insulation and initial fixation between them. Then, welding is used to reinforce the ends of the stator core prototype, resulting in the stator core. This combines adhesive bonding with end welding, improving the traditional secondary heating and curing process by using a sequence of room-temperature curing followed by welding reinforcement. Compared to traditional pure bonding or pure welding solutions, this method is superior in maintaining low iron loss characteristics and structural strength, achieving a synergistic effect of bonding for magnetic preservation and welding for reinforcement. This solves the problem of balancing magnetic and mechanical properties in traditional processes. Attached Figure Description

[0027] Figure 1 This is a flowchart of the present invention;

[0028] Figure 2 This is a schematic diagram of the dispensing process of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0030] This invention provides the following: Figure 1-2 The illustrated stator core bonding and welding composite connection process includes the following steps:

[0031] Step 1: Punch the silicon steel strip into stator laminations and stack them to form an annular lamination group;

[0032] The silicon steel strip is set as cold-rolled non-oriented silicon steel strip 20SW1200 with a thickness of 0.20mm; the silicon steel strip is stacked in the following ways: self-fastening or overlapping riveting.

[0033] In step 1, 0.20mm thick, 20SW1200 non-oriented silicon steel strips are used to punch stator sheets, which are then assembled in a ring and formed into a ring-shaped stator core through self-locking riveting. This not only reduces high-frequency iron loss and improves motor energy efficiency and power density by using the material itself, but also improves material utilization by punching the sheets. The self-locking riveting method, which avoids heat damage, ensures the mechanical tightness and vibration resistance of the core, while also fully protecting the interlayer insulation of the silicon steel sheets, avoiding additional losses caused by welding, and extending the overall lifespan of the machine.

[0034] Step 2: Spray a layer of curing agent onto both ends of the annular loose piece group through the dispensing tray, then apply glue to the curing agent coating, and press the stator loose pieces together to bond them into a stator core prototype.

[0035] During the dispensing process, the stator segments are positioned by external tooling, and the segments are pressed together after the adhesive has penetrated into the tiny gaps between them.

[0036] The adhesive is set as Pared anaerobic adhesive, and the curing agent is set as Pared curing agent; the adhesive and curing agent are mixed in a 1:1 ratio, and the curing time is 60 seconds. After curing, the adhesive forms an insulating bonding layer, and the curing is indicated by the segmented stator core prototype being in a hardened and non-dispersed state.

[0037] The dispensing temperature is set to 20-30℃, and the humidity is ≤65%. For every 10 finished products in a single section, spray with stamping oil to prevent rusting.

[0038] When not in use, the adhesive and hardener should be stored in a refrigerator at a temperature of 2℃-8℃ to ensure that they are in a stable storage condition, maintain their shelf life, and prevent performance failure. When taking them out, the refrigerator door should be closed in time to ensure temperature stability, and a record of adhesive inflow and outflow should be kept to ensure accurate inventory data.

[0039] As per the instruction manual Figure 1As shown, the adhesive is applied to the inner and outer rings of the annular lamination group. Using the center of the ring as a reference, adhesive is applied circumferentially to the teeth and yoke on both ends of the stator core prototype.

[0040] After dispensing the adhesive, spread it evenly on the loose sheet to present the predetermined shape, requiring no accumulation, no shrinkage, and no unevenness;

[0041] The number of adhesive dots in the inner ring (i.e., the stator slot) must be at least 54, the number of adhesive dots in the outer ring must be at least 54, the number of consecutive empty adhesive dots must be at most 3, the adhesive dots in the inner and outer rings corresponding to the teeth and yoke must not be empty at the same time, that is, at least 1 effective adhesive dot must be reserved in the stator slot between every two loose pieces, and the adhesive dots of a single piece must show good granular shape.

[0042] In step 2, the adhesive cures under the action of the curing agent, forming a solid insulating adhesive layer. This creates an insulating barrier between adjacent silicon steel sheets, increasing the contact thermal resistance at the inter-sheet interface and preventing excessive conduction of welding heat into the core. This results in a composite stator core that is both bonded and magnetically sound, ensuring that the low eddy current characteristics of the high-grade material are maintained. At the same time, it improves both parallelism and flatness, specifically from 0.8-1 mm to 0.3-0.6 mm.

[0043] At the same time, by using a combination of glue and hardener, the thickness of the glue layer, the glue application on the end face, and the glue filling of the gaps can be kept uniform and consistent under the curing temperature of room temperature.

[0044] Furthermore, by fully filling the gaps between the stator laminations, the annular lamination group can achieve inter-laminar insulation sealing and preliminary fixation without heating under normal temperature conditions, thus fully protecting the original electromagnetic properties of the silicon steel strip and avoiding the increase in iron loss caused by high temperature thermal stress.

[0045] Step 3: Leave a fine gap between the laminations at the intervals of the insulating adhesive layer, and weld the ends of the stator core prototype as a whole to obtain the stator core;

[0046] The welding process specifically involves: performing laser welding sequentially along the outer peripheral sidewall of the stator core prototype to reinforce the ends of the stator core prototype;

[0047] The weld width is 1-2mm, the weld penetration is 0.6-1.5mm, and the weld surface protrusion is less than 0.3mm;

[0048] In step 3, laser welding is used to reinforce the end structure of the stator core prototype, utilizing a laser energy density as high as 10. 6 -10 8The W / cm² characteristic enables millisecond-level rapid melting and cooling, forming a small heat-affected zone, ensuring that the weld is dense and has few defects such as porosity and cracks, while minimizing the additional impact on the magnetic properties of adjacent areas.

[0049] Meanwhile, after the adhesive has cured and formed an insulating bonding layer, the ends of the annular slab assembly are welded together. This creates a composite structure at the ends of the annular slab assembly that combines adhesive bonding for magnetic preservation and welding for strength. This integrates the low iron loss gain of the adhesive method with the high structural strength of the welding method, achieving a synergistic effect of magnetic preservation and strength.

[0050] Step 4: Integrate the pressing, dispensing, and welding processes to form a complete, automated stator core composite curing production line with fully adjustable parameters;

[0051] Among them, controlling the timing of dispensing and welding actions can avoid mutual interference between the two processes (such as the effect of welding heat on the thermal aging of the cured adhesive layer), and implementing a dual-layer circulation detection and feedback mechanism to achieve closed-loop control and full-process traceability of key process parameters such as adhesive flow rate, dispensing trajectory, welding power, and welding speed.

[0052] In step 4, driven by the goal of achieving mass production, multiple processes such as precision pressing, room temperature gluing, stator lamination flipping, end face welding of the ring lamination group, and online visual quality inspection are all integrated into a fully automated production line according to the cycle time plan. This realizes the joint operation of end gluing and welding and high-cycle continuous production, ensuring product consistency and stability.

[0053] Step 5: Establish a performance testing and evaluation system to test and evaluate the performance of stator cores produced on the stator core composite curing production line;

[0054] The performance testing and evaluation system includes comprehensive testing of the stator core's flatness, parallelism, and perpendicularity.

[0055] Verification experiment:

[0056] To verify the effect of the adhesive-welding composite connection process proposed in this invention on improving the form and position accuracy of the stator core, several stator core samples were prepared using the end-face adhesive bonding and welding process of this invention and the traditional direct welding process, respectively. Their flatness, parallelism, and perpendicularity form and position tolerances were compared and tested.

[0057] Both groups of samples used the same specifications of 0.20mm thick cold-rolled non-oriented silicon steel strip 20SW1200, with the same stacking method and welding parameters. Five samples (numbered #1 to #5) were randomly selected from each group for testing.

[0058] Testing items:

[0059] A-surface flatness Z1 (single end face flatness), A-surface flatness Z1+Z2 (cumulative flatness of both end faces), A-surface flatness Z1+Z2+Z3 (cumulative flatness of multiple segments), parallelism (Z1+Z2), perpendicularity.

[0060] The test results are shown in Table 1-3 below:

[0061] Table 1:

[0062]

[0063] Table 2:

[0064]

[0065] Table 3:

[0066]

[0067] Results analysis:

[0068] As shown in Tables 1-3 above, the stator core prepared using the adhesive-welding composite connection process of this invention exhibits significantly better dimensional and positional tolerances than the traditional directly welded stator core. Specifically:

[0069] (1) In terms of flatness: the average improvement of flatness of a single end face (Z1) is about 0.113 mm, with an improvement of about 68.7%; the average improvement of the cumulative flatness of both end faces (Z1+Z2) is about 0.377 mm, with an improvement of about 82.5%; the average improvement of the cumulative flatness of multiple segments (Z1+Z2+Z3) is about 0.706 mm, with an improvement of about 85.3%. It can be seen that as the number of inspection segments increases, the improvement effect of this process on flatness becomes more significant, indicating that the adhesive pre-fixing effectively suppresses the cumulative deformation caused by welding thermal stress.

[0070] (2) Parallelism: The average improvement in parallelism of the two end faces is about 0.140 mm, with an improvement of about 54.5%. This indicates that the insulating adhesive layer formed after the end face adhesive is cured creates a uniform adhesive interface between the silicon steel sheets, which can effectively ensure the parallelism accuracy of the two end faces.

[0071] (3) In terms of verticality: the verticality was improved by an average of about 0.094 mm, with an improvement of about 76.7%, indicating that this process can better ensure the perpendicular relationship between the stator core axis and the end face, which is beneficial to the subsequent motor assembly accuracy;

[0072] It can be concluded that the stator core bonding and welding composite connection process described in this invention, through the sequential design of first pre-fixing with adhesive at room temperature and then welding at the ends, utilizes the insulating adhesive layer to firmly bond the silicon steel sheets together before welding to form an overall rigid constraint, effectively suppressing the warping deformation and cumulative deviation caused by thermal stress during the welding process. This significantly improves the flatness, parallelism, and perpendicularity of the stator core, i.e., the key form and position accuracy indicators, and all meet or even exceed the tolerance requirements. The process of this invention has significant technical effects in improving the stator core stacking accuracy and product consistency.

[0073] In summary, this invention, when producing stator cores, first uses adhesive to apply glue at room temperature to bond the stator laminations, achieving insulation sealing and initial fixation between the laminations. Subsequently, welding is used to reinforce the ends of the stator core prototype, thus producing the stator core. This combines the adhesive bonding and end welding processes. By designing the sequence of first curing the adhesive at room temperature and then welding for reinforcement, the traditional secondary heating curing process is improved into a combined process of room temperature adhesive bonding and end welding. Compared to traditional pure bonding or pure welding solutions, this solution is superior to the pure welding solution in maintaining low iron loss characteristics and superior to the pure bonding solution in terms of structural strength. It achieves a synergistic effect of bonding for magnetic preservation and welding for reinforcement, solving the problem of difficulty in simultaneously achieving magnetic and mechanical properties in traditional processes.

[0074] Specifically, by applying adhesive to both ends of the annular lamination group, the adhesive fully penetrates into the gaps between the stator laminations, completing the inter-laminar insulation sealing and preliminary fixation under normal temperature and no heating conditions, ensuring that the low eddy current characteristics of high-grade materials are maintained, and avoiding the increase in iron loss caused by high temperature thermal stress.

[0075] Meanwhile, the insulating adhesive layer formed after room temperature curing can effectively cut off the eddy current path between silicon steel strips, making the interlayer resistance significantly higher than that of a pure welded stator, reducing the eddy current loss of the iron core. In addition, the insulating adhesive layer can act as a thermal barrier layer in the subsequent welding process, using its low thermal conductivity to suppress the excessive conduction of welding heat into the stator iron core, limiting the heat-affected zone to the shallow area of ​​the outer peripheral sidewall, effectively protecting the magnetic properties of the silicon steel strip inside the stator iron core from high temperature damage.

[0076] After curing at room temperature, the ends of the iron core are welded together to form a synergistic technical system of adhesive magnetic preservation and welding reinforcement. This can significantly reduce the eddy current loss and hysteresis loss of the motor, thereby improving the overall energy efficiency of the motor. It solves the problems of thermal damage, insufficient strength and magnetic performance decay in traditional processes, so that the stator iron core has excellent characteristics of high structural strength, low iron loss, high stacking accuracy and high consistency. It meets the needs of mass production and stable production of the new generation of high-efficiency motors and can be adapted to the manufacturing needs of new energy vehicles, precision motors or other high power density iron cores.

[0077] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used above are only some embodiments described in this invention. Obviously, those skilled in the art can obtain other drawings based on these drawings.

[0078] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A composite bonding and welding process for stator cores, characterized in that: Includes the following steps: Step 1: Punch the silicon steel strip into stator laminations and stack them to form an annular lamination group; Step 2: Spray a layer of curing agent onto both ends of the annular loose piece group through the dispensing tray, then apply glue to the curing agent coating, and press the stator loose pieces together to bond them into a stator core prototype. Step 3: Leave a fine gap between the laminations at the intervals of the insulating adhesive layer, and weld the ends of the stator core prototype as a whole to obtain the stator core; Step 4: Integrate the pressing, dispensing, and welding processes to form a complete, automated stator core composite curing production line with fully adjustable parameters.

2. Step 5: Establish a performance testing and evaluation system to test and evaluate the performance of stator cores produced on the stator core composite curing production line.

3. The bonding and welding composite connection process for stator cores according to claim 1, characterized in that: In step 1, the silicon steel strip is set as cold-rolled non-oriented silicon steel strip 20SW1200 with a thickness of 0.20mm; the silicon steel strip is stacked in the following ways: self-fastening or overlapping riveting.

4. The bonding and welding composite connection process for stator cores according to claim 1, characterized in that: In step 2, the stator segments are positioned by external tooling during dispensing, and are pressed together after the adhesive has penetrated into the fine gaps between the stator segments. The adhesive is Pared anaerobic adhesive, and the curing agent is Pared curing agent. The adhesive and curing agent are mixed in a 1:1 ratio, and the curing time is 60 seconds. After the adhesive cures, an insulating bonding layer is formed, and the curing of the adhesive is indicated by the segmented stator core prototype being in a hardened and non-dispersed state.

5. The bonding and welding composite connection process for a stator core according to claim 1, characterized in that: In step 2, adhesive is applied to the curing agent coating. The specific process is as follows: The adhesive is applied to the inner and outer rings of the annular lamination group, with the center of the ring as the reference, and the adhesive is applied circumferentially to the teeth and yokes on both ends of the stator core prototype. After dispensing the adhesive, spread it evenly on the loose sheet to present the predetermined shape, requiring no accumulation, no shrinkage, and no unevenness; The number of adhesive dots in the inner ring (i.e., the stator slot) must be at least 54, the number of adhesive dots in the outer ring must be at least 54, the number of consecutive empty adhesive dots must be at most 3, the adhesive dots in the inner and outer rings corresponding to the teeth and yoke must not be empty at the same time, that is, at least 1 effective adhesive dot must be reserved in the stator slot between every two loose pieces, and the adhesive dots of a single piece must show good granular shape.

6. The bonding and welding composite connection process for a stator core according to claim 4, characterized in that: In step 2, the dispensing temperature is set to 20-30℃ and the humidity is ≤65%. For every 10 finished products in a single section, spray and press oil once. When the glue and curing agent are not used, store them in a refrigerator and keep the refrigerator temperature between 2℃ and 8℃.

7. The bonding and welding composite connection process for a stator core according to claim 1, characterized in that: In step 3, the ends of the stator core prototype are welded as a whole. The specific process is as follows: laser welding is performed sequentially along the outer peripheral sidewall of the stator core prototype to reinforce the ends of the stator core prototype.

8. The bonding and welding composite connection process for a stator core according to claim 6, characterized in that: In step 3, the weld width is 1-2 mm, the weld penetration is 0.6-1.5 mm, and the weld plane protrusion is less than 0.3 mm.

9. The bonding and welding composite connection process for a stator core according to claim 1, characterized in that: In step 5, the performance testing and evaluation system includes: comprehensively testing the flatness, parallelism, and perpendicularity of the stator core.

Images