Modular sealed electric machine and method of assembly thereof

Abstract

The application discloses a modular sealed motor and an assembling method thereof, which comprises a stator assembly, a rotor assembly and an end cover sealing assembly; the stator assembly comprises a casing, a motor stator fixed in the casing and an insulating sealing body formed between the inner wall of the casing and the motor stator by vacuum-assisted pouring and solidification and filling all gaps without clearance; the rotor assembly comprises a motor rotor, a motor shaft in interference fit with the motor rotor and bearings press-fitted at both ends of the motor shaft; and the end cover sealing assembly comprises a front end cover, a rear end cover and a plurality of stud bolts in penetrating connection with the front end cover, the casing and the rear end cover. The application systematically solves the problems of the high-reliability sealed motor in structure, process and quality inspection, and finally makes the high-standard static sealing performance and the low-vibration noise dynamic operation performance be simultaneously ensured in the same simple and reliable mechanical structure.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more specifically, to a modular sealed motor and its assembly method. Background Technology

[0002] In the current motor manufacturing industry, traditional motor assembly methods have several significant drawbacks. First, the assembly of the motor stator and rotor typically relies on manual operation, which is not only inefficient but also prone to introducing human error, leading to inconsistent product quality. Second, existing assembly processes often lack precise temperature control and environmental monitoring, which can cause material performance degradation during assembly, affecting the long-term stability and reliability of the motor. Furthermore, internal electrical connections and sealing processes within the motor often encounter problems due to insufficient precision in the manufacturing process, increasing the risk of motor failure.

[0003] Furthermore, existing potting processes often leave micro-gaps between the stator and the housing due to insufficient fluidity of the colloid or incomplete degassing, affecting heat dissipation and sealing. Simultaneously, the end cover bearings are often secured using rigid gaskets, which cannot compensate for thermal deformation and wear, leading to a gradual increase in operating noise and vibration. More importantly, in traditional designs, stator sealing and bearing securing are often addressed separately, lacking an integrated solution. This results in complex motor structures, cumbersome assembly procedures, and difficulty in ensuring a balance between sealing reliability and operational stability.

[0004] The present invention aims to solve the above problems by proposing a more efficient, accurate and reliable modular sealed motor and its assembly method to improve the overall quality and production efficiency of the motor. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a modular sealed motor and its assembly method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A modular sealed motor includes a stator assembly, a rotor assembly, and an end cap sealing assembly;

[0008] The stator assembly includes a housing, a motor stator fixed inside the housing, and an insulating sealant formed between the inner wall of the housing and the motor stator by vacuum-assisted injection and curing, filling all gaps without gaps.

[0009] The rotor assembly includes a motor rotor, a motor shaft that is interference-fitted with the motor rotor, and bearings press-fitted at both ends of the motor shaft. The bearings are axially limited by circlips for the shaft.

[0010] The end cap sealing assembly includes a front end cap, a rear end cap, an annular sealing ring disposed in the sealing grooves of the front end cap and the rear end cap, multiple double-ended screws that connect the front end cap, the housing, and the rear end cap in a through-type manner, and an oil guide pipe for lubrication and cooling. In the end cap sealing assembly, the multiple double-ended screws penetrate the front end cap, the housing, and the rear end cap. Notably, the rear end cap and the housing have an axial clearance fit.

[0011] A wave-shaped elastic element, which is a wave washer, is provided between the rear end cover and the corresponding bearing outer ring.

[0012] The multiple double-ended screws penetrate the front end cover, the housing, and the rear end cover, and are locked with nuts. The locking force of the double-ended screws causes the front end cover and the rear end cover to press axially against the housing, thereby compressing the annular sealing ring. Simultaneously, the wave-shaped elastic element is disposed between the rear end cover and the outer ring of the bearing to apply a continuous axial preload to the outer ring of the bearing and to compensate for axial thermal expansion. The double-ended screws are locked with a preset torque value T.

[0013] An axial clearance is formed between the double-ended screw and the through hole on the rear end cover, so that the wave-shaped elastic element can independently perform the bearing preload function.

[0014] In this invention, the locking force of the double-ended screw is mainly used to press the front end cover axially against the housing to compress the annular sealing ring and achieve the main seal. At the same time, since the rear end cover and the housing are not rigidly connected, the wave-shaped elastic element set between the rear end cover and the bearing outer ring can independently apply a continuous axial preload to the bearing outer ring without being rigidly disturbed by the screw locking force, thereby effectively compensating for the thermal expansion and wear during motor operation and eliminating the axial clearance of the bearing.

[0015] Furthermore, the insulating sealant is formed by curing a two-component epoxy resin potting compound, and its mixed viscosity before curing is 800-1200 mPa·s at 25°C.

[0016] Furthermore, the inner hole of the housing and the outer circle of the motor stator are interference fits. The selection of the interference amount must simultaneously ensure the reliability of mechanical fixing and avoid deformation of the motor stator caused by excessive assembly stress. Through finite element analysis and experimental verification, this invention determines that the preferred interference amount is 0.12%-0.18% of the outer diameter of the motor stator (for example, for a stator with an outer diameter of 200mm, the interference amount is approximately 0.24mm-0.36mm). Within this range, it can ensure a tight fit between the stator and the housing under thermal expansion and contraction and vibration conditions to facilitate heat dissipation, while controlling the deformation of the stator silicon steel sheets within the allowable range and maintaining stable electromagnetic performance.

[0017] Furthermore, the free height H of the waveform elastic element and the working height h after compression satisfy: (Hh) / H=15%-25%; the bearing is a deep groove ball bearing or an angular contact ball bearing.

[0018] This invention provides an assembly method for a modular sealed motor, comprising three sequential process stages: stator module assembly, rotor module assembly, and assembly verification.

[0019] S1: Stator module assembly stage:

[0020] S11: The casing is heated in a controlled manner to make its inner hole expand uniformly to the target size. The heating temperature is 245℃-255℃ and the heat preservation time is not less than 1.5h.

[0021] S12: Under heating conditions, insert the motor stator axially into the housing;

[0022] S13: Natural cooling causes the housing to shrink and forms an interference fit with the motor stator;

[0023] S14: Inject insulating sealing material into the housing, and with the assistance of a vacuum degree not lower than -0.095MPa, allow it to flow and fill all gaps, and then cure it to form the insulating seal;

[0024] S2: Rotor module assembly stage:

[0025] S21: Select either heat-fitting or cold-pressing processes according to the type of motor to assemble the motor shaft and motor rotor into one piece. For induction motors, heat the motor rotor at 345℃-355℃ and then heat-fit it onto the motor shaft. For permanent magnet motors, press the motor shaft into the motor rotor at room temperature using a hydraulic press.

[0026] S22: Press bearings are installed at both ends of the motor shaft, and snap rings are installed to lock the bearings axially;

[0027] S3: Assembly Verification Phase

[0028] S31: Install annular sealing rings in the sealing grooves of the front and rear covers and apply grease;

[0029] S32: Sequentially assemble the front cover, the rotor assembly that completes the rotor module assembly stage, and the rear cover with the installed waveform elastic element;

[0030] S33: Use a torque wrench to tighten all double-ended screws to a preset torque value in a diagonal, crisscross sequence to secure the front end cover and the housing. The preset torque value is 20 N·m ± 5%. During assembly, the rear end cover maintains an axial clearance with the housing so that the wave-shaped elastic element can independently perform the bearing preload function.

[0031] S34: Perform an airtightness test on the assembled motor. Fill the motor with dry nitrogen or dry air at a test pressure of 0.25-0.3 MPa and hold the pressure for 15 minutes. The pass standard is that the pressure drop is less than 0.002 MPa.

[0032] Furthermore, in S11, an electric heating drying oven is used to heat the casing.

[0033] Furthermore, in step S14, the relative humidity of the environment is below 60% when the insulating sealant is injected.

[0034] Furthermore, in S33, the diagonal cross sequence is tightened in at least two rounds.

[0035] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0036] 1. An insulating sealant of a specific viscosity achieves gapless potting under vacuum assistance, simultaneously forming a primary sealing barrier and an excellent heat conduction channel, thus achieving basic sealing and efficient heat dissipation. Furthermore, the end cap sealing assembly, through a single tightening operation (tightening the double-ended screw), simultaneously and coupledly achieves two key functions: (a) compressing the end cap to create a reliable radial seal in the annular sealing ring; and (b) compressing the wave-shaped elastic element to provide precise and durable axial preload to the bearing. Traditionally, these two functions require different parts and processes to achieve. This invention cleverly integrates them, simplifying the structure, reducing assembly difficulty, achieving synergy between static sealing and dynamic pre-tightening, and ensuring the intrinsic matching and optimization between the sealing surface clamping force and the bearing pre-tightening force. In addition, the motor is decomposed into three major modules—stator, rotor, and end cover—for independent and precise assembly. Finally, the system is verified through quantitative airtightness testing. This systematically solves the structural, process, and quality inspection challenges of high-reliability sealed motors. Ultimately, it ensures both high-standard static sealing performance and low-vibration and noise dynamic operating performance in the same simple and reliable mechanical structure, thereby achieving a comprehensive performance leap in the motor in terms of IP68 sealing, long life, low noise, and high production consistency. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the modular sealed motor of the present invention.

[0038] Figure 2 This is an exploded structural diagram of the modular sealed motor of the present invention.

[0039] Figure 3 This is a flowchart of the assembly process of the present invention.

[0040] Figure 4 This is a schematic diagram of the structure of a waveform elastic element.

[0041] In the diagram: 1. Housing; 2. Motor stator; 3. Insulating seal; 5. Aviation socket; 6. Motor rotor; 7. Motor shaft; 8. Front cover; 9. Rear cover; 10. Annular seal; 11. Oil guide pipe; 12. Snap ring; 13. Waveform elastic element; 14. Double-ended screw; 15. Bearing; 16. Stainless steel ferrule connector. Detailed Implementation

[0042] The following is in conjunction with the accompanying drawings. Figures 1 to 4 The modular sealed motor and its assembly method of the present invention will be described in detail with reference to specific embodiments, so as to enable those skilled in the art to implement the present invention. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the scope of protection of the present invention.

[0043] It should be noted that the motor described in this invention can integrate various auxiliary functional components according to specific application requirements, such as the aviation socket 5 for signal transmission, the oil guide pipe 11 for cooling and lubrication, and the ferrule connector 16 for airtightness testing mentioned in the embodiments below. These components are not essential structures for realizing the core sealing and pre-tightening synchronous control function of this invention. Based on the concept of this invention, those skilled in the art can adaptively add or delete them according to actual working conditions. Their specific structures and working principles are only illustrative examples here and do not constitute a limitation on this invention.

[0044] Example 1: Structure of a Modular Sealed Motor

[0045] The modular sealed motor in this embodiment includes three main modules: stator assembly, rotor assembly, and end cover sealing assembly.

[0046] Stator assembly: Its core is a robust, sealed unit consisting of the housing 1, the motor stator 2, and the insulating seal 3. The housing 1 is made of high-strength cast aluminum alloy, and its inner hole is precision machined. The motor stator 2 is made of laminated silicon steel sheets with windings. After assembly, the inner wall of the housing 1 and the outer circle of the motor stator 2 core are tightly fixed by an interference fit. Based on optimized design, the interference amount in this embodiment is selected as 0.15% (i.e., 0.30 mm) of the stator outer diameter (e.g., 200 mm), ensuring good thermal conductivity and mechanical stability.

[0047] To achieve a higher level of sealing and insulation, after the motor stator 2 is installed into the housing 1, a two-component epoxy resin potting compound (e.g., Araldite® series potting compounds from Allenstad and Huntsman) is injected into its interior. This potting compound has a mixed viscosity of approximately 1000 mPa·s at 25°C, falling within the preferred range of 800-1200 mPa·s, exhibiting good flowability and penetration. With the assistance of a vacuum of not less than -0.095 MPa, the compound can fully penetrate all gaps in the stator windings and completely fill the annular space between the motor stator 2 and the inner wall of the housing 1, forming an insulating seal 3 after curing. This insulating seal 3 achieves a tight bond with the inner wall of the housing 1 and the surface of the stator windings. Cross-sectional electron microscopy reveals a dense and continuous interface region, effectively eliminating the main macroscopic and microscopic channels affecting sealing and heat conduction, thus constituting the first and primary sealing and insulation barrier for the motor.

[0048] Rotor assembly: includes motor rotor 6, motor shaft 7, bearings 15, and retaining rings 12. Motor rotor 6 is a cast aluminum induction rotor. During assembly, motor rotor 6 is placed in an oven and heated to 350℃ and held for 2 hours to allow its inner bore to expand uniformly. Subsequently, the precision-ground motor shaft 7 is quickly and vertically fitted into the shaft, allowing it to cool naturally in air to form a strong interference fit. After cooling, high-precision deep groove ball bearings 15 are pressed into both ends of the motor shaft 7 using a hydraulic press, and retaining rings 12 are immediately installed in the retaining ring grooves on the shaft to complete the axial rigid positioning of the bearings.

[0049] End cap sealing assembly: This assembly is crucial for achieving dynamic sealing and bearing preload. The front end cap 8 and rear end cap 9 are made of cast iron and have standard rectangular sealing ring grooves. A hydrogenated nitrile butadiene ring 10 is inserted into the groove and a layer of lubricant (such as vacuum pump oil) is applied evenly.

[0050] Specifically, before assembling the rear cover 9, a wave-shaped elastic element 13 made of carbon steel (i.e., a wave washer, such as...) is first installed. Figure 4 The washer (as shown) is fitted onto the motor shaft 7, making it fit snugly against the outer ring end face of the rear bearing 15. The free height H of this corrugated washer is 2.0 mm, and the designed working height h is 1.7 mm, satisfying the compression ratio requirement of (Hh) / H=15%.

[0051] During final assembly, eight double-ended screws 14 with a strength grade of 8.8 are used to pass through the front cover 8, the flange of the housing 1, and the rear cover 9. An axial clearance of 0.2mm-0.5mm is reserved between the double-ended screws 14 and the through holes on the rear cover 9, so that the rear cover 9 can float axially relative to the housing 1.

[0052] Using a calibrated torque wrench, tighten the nuts in two stages, strictly following a diagonal, alternating sequence, until the final torque is set to 20 N·m. This tightening force primarily acts on the front cover 8, pressing it axially against the housing 1, thereby compressing the annular seal 10 to form a reliable seal. Simultaneously, because the rear cover 9 is in a floating state, the wave-shaped elastic element 13 (wave washer) pre-installed between the rear cover 9 and the outer ring of the bearing 15 can freely expand and contract, independently applying and maintaining a constant axial preload on the bearing 15, thus effectively compensating for thermal expansion and wear during motor operation and eliminating axial clearance in the bearing.

[0053] Example 2: Assembly method of modular sealed motor

[0054] The assembly method of this motor follows the principles of modularity, parameterization, and verifiability, and is divided into three stages, as follows: Figure 3 As shown, this method closely aligns with the actual production processes used by customers.

[0055] Phase 1 S1: Stator Module Assembly

[0056] S11: Place the casing 1 in an electric heating drying oven, set the temperature to 250℃, and keep it at this temperature for 1.5 hours to ensure uniform expansion of the inner hole.

[0057] S12-S13: At the end of the heat preservation process, a robotic arm is used to quickly and accurately fit the motor stator 2, which is at room temperature, into the housing 1 along the axis. The assembly is then moved to a clean area to cool naturally to room temperature, completing the interference fit.

[0058] S14: After installing the aviation socket 5 and soldering the leads, the stator assembly is connected to the special potting fixture. Using a two-component metering potting machine, epoxy resin potting compound and curing agent are mixed online at a mass ratio of 100:13. Epoxy resin potting compound is poured into the housing 1, and under the assistance of a vacuum degree not lower than -0.095MPa, it is allowed to flow and fill all gaps. This vacuum degree is maintained until the potting is complete. The potting method adopts bottom single-point injection to avoid air bubble entrainment. Subsequently, it is cured for 24 hours in an environment with a temperature of 25℃±5℃ and a relative humidity of less than 55% to form the insulating sealant 3.

[0059] Phase 2 S2: Rotor Module Assembly

[0060] S21: For induction motors, the motor rotor 6 is heated at 350°C and then heat-fitted onto the motor shaft 7; for permanent magnet motors, the motor shaft 7 is pressed into the motor rotor 6 at room temperature using a hydraulic press.

[0061] S22: On a precision press, bearing 15 is press-fitted in force-displacement curve monitoring mode, and snap ring 12 is automatically assembled to complete the axial locking of bearing.

[0062] Phase 3, S3: Assembly and Verification

[0063] S31: Install annular sealing rings 10 in the sealing grooves of the front cover 8 and the rear cover 9, and apply grease.

[0064] S32: A wave-shaped elastic element 13 (wave washer) is provided between the rear end cover 9 and the outer ring of the corresponding bearing 15.

[0065] S33: On the automated assembly line, the sealing rings are greased and installed sequentially, the front end cover 8 is pre-installed, the rotor assembly is inserted into the stator assembly, and the rear end cover 9 with the wave elastic element 13 (wave washer) is assembled. For motors that require electrical signal output, aviation sockets 5 can be installed simultaneously; for motors that require additional cooling or lubrication, oil guide pipes 11 can be installed. Finally, all double-ended screws 14 are automatically tightened in two rounds in a diagonal, crisscrossing sequence by a multi-axis torque wrench system, with a final tightening torque of 20 N·m.

[0066] S34: To further verify the sealing reliability of the entire machine, an airtightness test was performed on the assembled motor. The motor was connected to a dedicated test bench. If the motor is equipped with a compression fitting 16, dry nitrogen (or dry air) can be introduced into the motor through this fitting. The pressure sensor monitored the pressure rise to 0.28±0.02MPa, then the valve was closed, and a pressure holding time of 15 minutes was started. The pass standard requires that the pressure drop does not exceed 0.5% of the initial pressure, i.e., the pressure drop value ΔP < 0.0014MPa. This test not only comprehensively verified the sealing effect of the annular sealing ring 10 and the integrity of the insulating sealing body 3, but also indirectly verified that all components were properly assembled and there were no structural leakage paths.

[0067] Example 3: Determination of the heating temperature range of the casing

[0068] To determine the heating temperature range of the housing in step S11, the present invention conducted the following research:

[0069] Thermal expansion calculation: The casing material is ZL101 aluminum alloy, and the coefficient of linear expansion α = 23 × 10⁻⁶. -6 / ℃. The outer diameter of the motor stator is D=200mm, and the design interference is δ=0.3mm. The minimum required heating temperature ΔT_min=δ / (α×D)=0.3 / (23×10 -6 (×200)≈65℃. Considering heat loss due to assembly operation time, the actual heating temperature should be higher than the calculated value.

[0070] Material property experiments: The mechanical properties of ZL101 aluminum alloy samples were tested after being held at different temperatures for 1.5 hours. The results are as follows:

[0071] Heating at 200℃: Tensile strength decreases by 3%, hardness decreases by 2%;

[0072] Heating at 250℃: Tensile strength decreases by 8%, hardness decreases by 6%;

[0073] Heating at 300℃: Tensile strength decreases by 22%, and hardness decreases by 18%;

[0074] Taking into account both thermal expansion requirements and material performance preservation, the heating temperature range was determined to be 245℃-255℃. Within this temperature range, the thermal expansion is sufficient (approximately 1.15 mm), and the degradation of material properties is controlled within an acceptable range (<10%).

[0075] Example 4: Verification of rotor heating temperature

[0076] Metallographic analysis was performed on the cast aluminum rotor (material ZL102) of the induction motor after heating at 350℃ for 2 hours. The results showed that:

[0077] No significant grain growth was observed in the aluminum matrix;

[0078] The eutectic silicon phase showed no obvious coarsening;

[0079] Microhardness change <5%.

[0080] This proves that the rotor material properties remain stable within this temperature range.

[0081] Example 5: Method for determining torque value

[0082] Since the rear cover is floatingly connected to the double-ended screw through axial clearance, the locking torque of the screw is only used to overcome the compression reaction force of the front cover sealing ring, and not directly used to compress the wave elastic element 13 (wave washer).

[0083] Establish a torque-compression relationship model:

[0084] The force-compression curve of the annular seal 10 was obtained through a compression test, and the compressive force corresponding to the target compression ratio of 20% was determined. =120N;

[0085] According to the threaded transmission formula T=K× ×d, where K is the torque coefficient. In this embodiment, K=0.2 and d=8mm were measured under the condition that molybdenum disulfide grease was applied to the thread surface of the double-ended screw 14 and the thread accuracy was 6H. The calculated T=0.2×120N×8mm=192N·mm≈0.192N·m.

[0086] Taking into account the assembly process margin and the fluctuation of the friction coefficient, the preset torque value was finally determined to be 20 N·m ± 5%.

[0087] The preload of the wave elastic element 13 (wave washer) is determined by its own free height and the actual compression after installation, and is independent of the locking torque of the double-ended screw.

[0088] Verification using 10 prototypes showed that, after assembly with a torque of 20 N·m ± 5%, the measured compression rate of the sealing ring was 19.5%-21.2%, and the compression rate of the wave gasket was 18.8%-22.3%, meeting the design requirements.

[0089] Example 6: Comparison of Effects

[0090] To verify the effectiveness of the technical solution of this invention, 30 induction motors with a rated power of 5.5kW and a rated speed of 1500r / min produced in the same batch were selected as test objects. The stator outer diameter of the motor was 200mm, and the housing material was ZL101 aluminum alloy. The 30 motors were randomly divided into three groups of 10 each, and assembled using the following three schemes:

[0091] Control group A: Traditional rigid gaskets + experience torque assembly (torque value is set based on operator experience and is not designed in conjunction with seal compression and bearing preload).

[0092] Control group B: A wave-shaped washer was used, but no related parameters were designed (the free height of the wave-shaped washer H=2.0mm, the working height after assembly h=1.7mm, the compression rate 15%, but the sealing and pre-tightening were not coordinated and controlled by the locking force of the double-ended screw).

[0093] Experimental Group C: Using the scheme of this invention (correlation parameters + optimized torque), the locking torque of the double-headed screw was determined to be 20 N·m ± 5% according to the method described in Example 5, and the compression rate of the waveform elastic element 13 (wave washer) was controlled within the range of 15%-25%.

[0094] All test motors were tested under the same conditions, specifically as follows:

[0095]

[0096] The test results are the average of 10 motors in each group. The specific data is shown in the table below:

[0097]

[0098] The low temperature rise and low vibration characteristics of experimental group C are attributed to the floating design of the rear end cover in this invention combined with the use of the wave elastic element 13 (wave washer), which effectively isolates the influence of thermal deformation of the housing on the bearing position, rather than simply relying on the screw locking force.

[0099] The above test results show that, compared with control groups A and B, experimental group C has significantly improved in vibration suppression (vibration value reduced by 44%-64% after 1000h), sealing reliability (100% pass rate), and thermal management (bearing temperature rise reduced by 14%-24%). This verifies the effect of the present invention in achieving integrated control of sealing and bearing preload through synchronous locking of double-headed screws.

[0100] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0101] In this invention, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0102] The control method of this invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the art. Furthermore, since this invention is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail here.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A modular sealed motor, characterized in that, include: Stator assembly, rotor assembly and end cover sealing assembly; The stator assembly includes a housing (1), a motor stator (2) fixed inside the housing (1), and an insulating seal (3) formed by vacuum-assisted injection and curing between the inner wall of the housing (1) and the motor stator (2), filling all gaps without gaps. The rotor assembly includes a motor rotor (6), a motor shaft (7) that is interference-fitted with the motor rotor (6), and bearings (15) press-fitted at both ends of the motor shaft (7). The bearings (15) are axially limited by a circlip (12) for the shaft. The end cap sealing assembly includes a front end cap (8), a rear end cap (9), an annular sealing ring (10) disposed in the sealing groove of the front end cap (8) and the sealing groove of the rear end cap (9), multiple double-ended screws (14) that are connected to the front end cap (8), the housing (1) and the rear end cap (9) in a through manner, and an oil guide pipe (11) for lubrication and cooling. The rear end cover (9) and the housing (1) are fitted with an axial clearance; and a wave-shaped elastic element (13) is provided between the rear end cover (9) and the outer ring of the corresponding bearing (15); the compression rate of the wave-shaped elastic element (13) is 18.8%-22.3%; The multiple double-ended screws (14) penetrate the front end cover (8), the housing (1), and the rear end cover (9), and are locked with nuts. The locking force of the double-ended screws (14) causes the front end cover (8) and the rear end cover (9) to press axially against the housing (1) to compress the annular seal ring (10). At the same time, the wave-shaped elastic element (13) is disposed between the rear end cover (9) and the outer ring of the bearing (15) to apply a continuous axial preload to the outer ring of the bearing (15) and to compensate for axial thermal expansion. The compression rate of the annular seal ring (10) is 19.5%-21.2%. An axial clearance is formed between the double-ended screw (14) and the through hole on the rear end cover (9) so that the wave elastic element (13) can independently perform the bearing preload function.

2. The modular sealed motor according to claim 1, characterized in that, The insulating sealant (3) is formed by curing a two-component epoxy resin potting compound, and its mixed viscosity before curing is 800-1200 mPa·s at 25°C.

3. The modular sealed motor according to claim 1, characterized in that, The inner hole of the housing (1) and the outer circle of the motor stator (2) are interference fit, and the interference amount is 0.12%-0.18% of the outer circle diameter of the motor stator (2).

4. An assembly method for assembling a modular sealed motor as described in any one of claims 1-3, characterized in that, The process includes three sequential stages: stator module assembly, rotor module assembly, and assembly verification. S1: Stator module assembly stage: S11: The casing (1) is heated in a controlled manner to make its inner hole expand uniformly to the target size. The heating temperature is 245℃-255℃ and the heat preservation time is not less than 1.5h. S12: Under heating conditions, insert the motor stator (2) into the housing (1) axially; S13: Natural cooling causes the housing (1) to shrink and form an interference fit with the motor stator (2); S14: Insulate and seal the housing (1) with insulating sealant, and allow it to flow and fill all gaps with the assistance of a vacuum degree not lower than -0.095MPa, and then solidify to form the insulating seal (3). S2: Rotor module assembly stage: S21: Select either hot-fitting or cold-pressing process according to the type of motor to assemble the motor shaft (7) and the motor rotor (6) into one piece. For induction motors, heat the motor rotor (6) at 345℃-355℃ and then hot-fit it onto the motor shaft (7). For permanent magnet motors, press the motor shaft (7) into the motor rotor (6) at room temperature using a hydraulic press. S22: Press bearings (15) onto both ends of the motor shaft (7) and install snap rings (12) to axially lock the bearings (15); S3: Assembly Verification Phase S31: Install annular sealing rings (10) in the sealing grooves of the front cover (8) and the rear cover (9) and apply grease; S32: Assemble the front end cover (8), the rotor assembly that completes the rotor module assembly stage, and the rear end cover (9) with the installed waveform elastic element (13) in sequence. S33: Use a torque wrench to tighten all the double-ended screws (14) in a diagonal, alternating sequence to a preset torque value to rigidly lock the front cover (8) and the housing (1), the preset torque value being 20 N·m ± 5%; During the tightening process, the rear end cover (9) remains floating through the axial movement gap between it and the double-ended screw (14), allowing the wave elastic element (13) to independently perform the bearing preload function; S34: Perform an airtightness test on the assembled motor. Fill the motor with dry nitrogen or dry air at a test pressure of 0.25-0.3 MPa and hold the pressure for 15 minutes. The pass standard is that the pressure drop is less than 0.002 MPa.

5. The assembly method according to claim 4, characterized in that, In S11, an electric heating drying oven is used to heat the casing (1).

6. The assembly method according to claim 4, characterized in that, In step S14, the relative humidity of the environment is below 60% when the insulating sealant is injected.

7. The assembly method according to claim 4, characterized in that, In S33, the diagonal cross sequence is tightened in at least two rounds.

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