Method of assembling a motor for a cryogenic device

Abstract

The application relates to an assembling method of a motor for a low-temperature device, and the assembling method comprises the following steps: S1, cutting and embedding an oil felt into a fixing groove of a fixing ring to form a lubricating assembly, immersing the lubricating assembly into lubricating grease until the lubricating assembly is completely infiltrated, and then taking out the lubricating assembly and draining surface grease; S2, embedding the lubricating assembly obtained in the step S1 into an installation cavity of a lubricating seat; S3, respectively installing a supporting bearing and a check ring assembly into an installation shell, assembling and connecting a rotating shaft with the supporting bearing after the rotating shaft passes through the check ring assembly; then, installing a stator mechanism on the installation shell, and completing a wiring process; S4, fixing the lubricating seat on the installation shell; S5, installing a dustproof assembly at a cover shell, placing the dustproof assembly on a pressing equipment, installing the installation shell obtained in the step S3 on the pressing equipment, and oppositely arranging the cover shell relative to the installation shell; tightly and closely connecting the cover shell and the installation shell through the pressing equipment, making one end of the rotating shaft pass through the dustproof assembly and extend out of the cover shell; and S6, pressing and closing the other end of the installation shell through a cover. The assembling precision is improved through cooperation between the assembling steps.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to an assembling method of an electric machine for low-temperature equipment. BACKGROUND

[0002] The electric machine used in low-temperature equipment such as low-temperature refrigeration equipment and low-temperature experimental devices needs to be operated stably for a long time, which puts forward strict requirements on the assembling precision, lubrication reliability, sealing performance and structural stability of the electric machine. The low-temperature environment in the low-temperature equipment is usually lower than 0℃, and in some scenarios, it can be as low as-40℃ or even lower. A fan device is installed in the low-temperature equipment, and the fan device drives the impeller through the electric machine to realize the gas circulation in the corresponding space in the low-temperature equipment. Due to the small installation space of the low-temperature equipment, the axial installation size of the electric machine is required to be small, so as to avoid the fan device occupying too much space of the wall body of the low-temperature equipment, thereby affecting the heat preservation effect. The publication with the announcement number CN212162977U provides a brushless direct current motor with a closed stator. The motor includes a housing, a stator and a circuit board arranged in the housing, a rotor cooperatively arranged in the stator, a front end cover arranged on one side of the housing and a rear end cover arranged on the other side of the housing, and the front end cover and the rear end cover are in sealing connection with the housing, and the two ends of the rotor are arranged in the front end cover and the rear end cover through bearings respectively.

[0003] However, the electric machine is provided with bearings at the front end and the rear end, and it is difficult to effectively reduce the axial installation size, and the assembly coaxiality deviation of the rotor mechanism and the bearings is large, and the vibration is intensified during operation, thereby affecting the service life of the electric machine. Moreover, under the condition that the low-temperature environment and the external lubricating grease cannot be supplemented for a long time, the electric machine needs to maintain stable working performance, and the bearings need to rotate flexibly under the lubrication of the lubricating grease. However, the existing lubricating assembly is not fully infiltrated, and the flowability of the lubricating grease is reduced in the low-temperature environment, which easily leads to lubrication failure of the bearings, thereby causing the electric machine to be stuck or worn, and the technical problem of the lubricating grease needing to be supplemented regularly. Therefore, it is necessary to be improved. SUMMARY

[0004] In order to overcome the problems in the related art, the embodiments of the present application provide an assembling method of an electric machine for low-temperature equipment, which is used to solve the technical problems of large axial installation size of the electric machine and small lubricating grease storage.

[0005] According to a first aspect of the embodiments of the present application, an assembling method of an electric machine for low-temperature equipment is provided, the electric machine includes a housing, a rotor mechanism, a stator mechanism and a support bearing, the housing includes a mounting shell, a cover shell and a lubricating seat, and the assembling method includes the following steps:

[0006] S1, cut the oil felt and embed it into the fixing groove of the fixing ring to form a lubricating assembly, so that the oil felt is flush or slightly exceeds the opening of the fixing groove; a plurality of lubricating holes are arranged at intervals at the bottom of the fixing groove; immerse the lubricating assembly in lubricating grease until it is fully infiltrated, and then take it out and drain the surface grease;

[0007] S2, embedding the lubricating assembly obtained in step S1 into the mounting cavity of the lubricating seat, forming a grease storage space between the fixing ring and the bottom of the mounting cavity, and filling the grease storage space with lubricating grease;

[0008] S3, respectively installing the support bearing and the retainer assembly to the mounting shell, assembling the rotating shaft of the rotor mechanism through the retainer assembly and connecting with the support bearing, forming a grease isolation space between the retainer assembly and the end face of the support bearing; then installing the stator mechanism on the mounting shell and completing the wiring process;

[0009] S4, fixing the lubricating seat to the mounting shell, and the oil felt faces the support bearing and maintains a predetermined lubrication gap;

[0010] S5, installing a dustproof assembly at the shell and placing it in a press-fitting device, installing the mounting shell obtained in S3 in the press-fitting device opposite to the shell; tightly connecting the shell and the mounting shell by the press-fitting device, so that one end of the rotating shaft passes through the dustproof assembly and extends out of the shell;

[0011] S6, press-fitting the end cover to close the other end of the mounting shell.

[0012] In an embodiment, the tightly connecting the shell and the mounting shell by the press-fitting device comprises:

[0013] determining a predetermined press-fitting area on the outer peripheral wall of the mounting shell;

[0014] cleaning the press-fitting area with a cleaning agent, and drying after cleaning;

[0015] coating a predetermined thickness of lubricant on the surface of the press-fitting area;

[0016] controlling the press-fitting device to move downward and press-fitting the shell and the predetermined press-fitting area of the mounting shell.

[0017] In an embodiment, the controlling the press-fitting device to move downward and press-fitting the shell and the predetermined press-fitting area of the mounting shell comprises:

[0018] putting the shell into the positioning base of the tool and fixing it by the positioning pin, and then putting the mounting shell into the tool and positioning it by the guide sleeve;

[0019] controlling the press-fitting speed of the press-fitting device to be 5 mm / s ~ 10 mm / s, and applying pressure;

[0020] real-time monitoring the pressure curve of the press-fitting device;

[0021] when the press-fitting device is in place, maintaining the pressure for 5 s ~ 10 s to tightly fit the shell and the mounting shell.

[0022] In an embodiment, the real-time monitoring of the pressure curve of the press-fitting device comprises:

[0023] acquiring the pressure parameter through a sensor installed on the press head;

[0024] acquiring the displacement parameter of the press head through a displacement sensor;

[0025] comparing the pressure parameter and the displacement parameter with the built-in standard pressure-displacement curve;

[0026] when the pressure parameter and the displacement parameter are within the deviation range, continue the press-fitting;

[0027] when the pressure parameter and / or the displacement parameter are out of the deviation range, stop the press-fitting.

[0028] In an embodiment, the mounting shell forms a sealing protrusion at the edge of the press-fitting area, and the height of the sealing protrusion is 3-5 mm;

[0029] The press-fitting connection of the cover shell and the preset press-fitting area of the mounting shell comprises: heating the end of the cover shell to 120-150°C by induction heating, and after holding for 2-3 min, press the cover shell into the press-fitting area until the end of the cover shell gradually unfolds along the sealing protrusion and fits.

[0030] In an embodiment, the immersion of the lubricating assembly into the lubricating grease to complete the immersion comprises:

[0031] putting a plurality of lubricating assemblies into the lubricating grease in the immersion tank;

[0032] sending the immersion tank into a negative pressure device, controlling the immersion tank to be in a negative pressure environment, controlling the immersion environment temperature to be 0-5°C, and standing still for 10-20 min under this condition;

[0033] controlling the negative pressure device to slowly recover to standard atmospheric pressure, and then taking out the lubricating assembly from the immersion tank.

[0034] In an embodiment, an annular oil return groove and at least one branch oil way are formed on the rotating shaft, the branch oil way communicates with the annular oil return groove, the annular oil return groove is located in the grease isolation space formed in step S3, the oil outlet of the branch oil way extends to the end of the rotating shaft, and before assembling the rotor mechanism, the inner wall of the annular oil return groove and the branch oil way is smeared with lubricating grease.

[0035] In an embodiment, the supporting bearing is an oil-containing bearing.

[0036] In an embodiment, the dustproof assembly comprises a fixing member and a silica gel sealing ring mounted on the fixing member, an inner ring of the silica gel sealing ring is provided with an annular lip, and the annular lip is in interference fit with the rotating shaft; when the dustproof assembly is mounted, a circle of sealing glue is first coated in the mounting groove of the cover shell, then the dustproof assembly is embedded in the mounting groove and compacted, and the cover shell and the mounting shell are pressed and assembled after standing for 5-8 min.

[0037] In an embodiment, at least three positioning bosses are uniformly and circumferentially protruded on the outer peripheral wall of the stator mechanism, and the inner wall of the mounting shell is provided with adapted positioning grooves corresponding to the positioning bosses.

[0038] When the stator mechanism is assembled, the positioning bosses of the stator mechanism are embedded in alignment with the positioning grooves of the mounting shell, so that the positioning bosses are in interference fit with the positioning grooves.

[0039] The technical scheme provided by the embodiment of the application can have the following beneficial effects: the lubricating assembly is fully impregnated with lubricating grease, so as to increase the storage amount of lubricating grease, stabilize the lubricating area, and prolong the lubricating time. The lubricating assembly and the mounting cavity further have a grease storage space, so as to further increase the storage amount of lubricating grease. The retaining ring assembly limits the lubricating grease on both sides of the supporting bearing, so as to reduce the risk of the lubricating grease entering the active area of the rotor mechanism and reduce the risk of lubricating grease leakage. The cooperation between the assembly steps improves the assembly precision. The cover shell and the mounting shell are pressed and assembled in close fit, so as to improve the close fit and reduce the size of the outer peripheral wall, and fastening members are not needed for locking connection. BRIEF DESCRIPTION OF DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application.

[0041] Figure 1 is a flow block diagram showing an assembly method of the motor according to an embodiment.

[0042] Figure 2 is a sectional structure schematic diagram of the motor according to an embodiment.

[0043] Figure 3 is an exploded structure schematic diagram of the motor according to an embodiment.

[0044] Figure 4 is a physical diagram of the motor according to an embodiment.

[0045] In the figure, the stator mechanism is 10; the rotor mechanism is 20; the rotating shaft is 21; the annular oil return groove is 211; the branch oil passage is 212; the housing is 30; the mounting shell is 31; the bearing hole is 311; the retaining ring hole is 312; the press-fit area is 313; the sealing protrusion is 314; the cover is 32; the lubrication seat is 33; the mounting cavity is 331; the end cover is 34; the support bearing is 40; the lubrication assembly is 50; the oil felt is 51; the fixing ring is 52; the lubrication hole is 521; the fixing groove is 522; the retaining ring assembly is 60; the rigid support part is 61; the elastic part is 62; the dustproof assembly is 70; the fastener is 71; the silicone sealing ring is 72; and the sealing ring is 80. Detailed Implementation

[0046] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images, and should not be construed as limiting the invention. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art.

[0047] like Figures 1 to 4 As shown, the present invention provides a method for assembling a motor for cryogenic equipment. The motor includes a housing 30, a rotor mechanism 20, a stator mechanism 10, and a support bearing 40. The housing 30 includes a mounting shell 31, a cover 32, and a lubrication seat 33. Preferably, the mounting shell 31 is formed by casting, die casting, or machining. Preferably, the lubrication seat 33 is a rigid seat structure that can be used in combination with the mounting shell 31.

[0048] The assembly method of the motor includes the following steps:

[0049] S1, the roofing felt 51 is cut and embedded into the fixing groove 522 of the fixing ring 52 to form a lubrication assembly 50, so that the roofing felt 51 is flush with or slightly exceeds the opening of the fixing groove 522; the bottom of the fixing groove 522 has multiple spaced lubrication holes 521. The lubrication assembly 50 is immersed in grease until fully saturated, and then drained of excess grease. In this step, the roofing felt 51 is cut into a shape that fits the fixing groove 522 of the fixing ring 52 and embedded into the fixing groove 522, ensuring that the roofing felt 51 is flush with the opening of the fixing groove 522. The fixing ring 52 has a disc-shaped structure, and the outer peripheral wall of the fixing ring 52 is adapted to the inner wall structure of the mounting cavity 331. The fixing groove 522 has a recessed groove structure, optionally a circular groove, a rectangular groove, or a groove structure with positioning protrusions inside. The fixing groove 522 can accommodate and limit the roofing felt 51.

[0050] Optionally, the bottom of the fixing groove 522 is provided with four, six, eight, twelve or twenty lubricating holes 521 arranged uniformly in intervals; or the bottom of the fixing groove 522 is provided with a sieve hole structure arranged in intervals. The lubricating hole 521 can communicate the space outside the bottom of the fixing groove 522 with the oil felt 51 in the fixing groove 522, so that the lubricating grease enters the fixing groove 522. In particular, when the motor is in the application state, the height of the space at the bottom of the fixing groove 522 is greater than the height of the opening size of the fixing groove 522, and the oil felt 51 can maintain a contact state with the external lubricating grease.

[0051] In order to improve the infiltration effect of the lubricating grease in the lubricating assembly 50, a negative pressure and low temperature cooperative infiltration process is adopted. The lubricating assembly 50 is infiltrated with lubricating grease in a negative pressure state to improve the content of the lubricating grease and discharge gas. The infiltration process of the lubricating assembly 50 includes the following steps:

[0052] S11, the plurality of lubricating assemblies 50 are placed in the lubricating grease in the infiltration tank; the plurality of lubricating assemblies 50 are uniformly arranged and placed in the lubricating grease in the infiltration tank, so as to ensure that each lubricating assembly 50 is completely submerged and does not contact each other, and to avoid local insufficient infiltration caused by stacking of the lubricating assemblies 50.

[0053] S12, the infiltration tank is sent into a negative pressure device, the infiltration tank is controlled to be in a negative pressure environment, the infiltration environment temperature is in the range of 0°C-5°C, and the infiltration tank is kept still for 10-20 minutes under the condition. The infiltration tank is smoothly sent into the sealed cavity of the negative pressure device, the sealing door is closed and the sealing of the sealed cavity of the negative pressure device is ensured. The sealing door ensures the sealing of the negative pressure device, avoids the negative pressure leakage affecting the infiltration effect, and ensures the stable implementation of the negative pressure and low temperature cooperative infiltration process.

[0054] The infiltration environment temperature is in the low temperature range of 0°C-5°C. Compared with normal temperature infiltration, the low temperature environment can avoid the softening and loss of the lubricating grease due to too high temperature, and ensure that the lubricating grease can be stably attached to the inside of the assembly after infiltration. The infiltration environment temperature is higher than the dropping point temperature of the lubricating grease, which can ensure that the lubricating grease still has sufficient permeability and flowability, and realizes the deep infiltration of the micro-porous structure in the lubricating assembly 50. Preferably, the negative pressure device monitors the environment temperature in the infiltration tank in real time through a temperature sensor, so that the environment temperature is stably kept in the range of 0°C-5°C.

[0055] The lubricating assembly 50 is controlled to be infiltrated for 10-20 minutes in the above negative pressure and low temperature environment. Through the continuous negative pressure effect, the lubricating grease gradually permeates into each micro-porous structure of the lubricating assembly 50, and the overall gap infiltration effect of the lubricating assembly 50 is realized.

[0056] S13, the negative pressure device is controlled to slowly recover to standard atmospheric pressure, and then the lubricating assembly 50 is taken out of the immersion tank. After the lubricating assembly 50 is immersed, the negative pressure device is controlled to slowly recover to standard atmospheric pressure, and the recovery rate of the air pressure in the negative pressure device is controlled to be between 0.01 MPa / s and 0.03 MPa / s, so that the instantaneous impact force generated by the sudden change of pressure does not damage the formed grease adsorption structure in the lubricating assembly 50, the grease is prevented from being precipitated from the micropores due to the sudden change of pressure, and the stability of the immersion effect is ensured. After the lubricating assembly 50 is slowly taken out of the immersion tank, the grease floating on the surface of the lubricating assembly 50 is drained by a cleaning tool, and at this time, the micropores in the lubricating assembly 50 are completely filled with grease, which provides stable conditions for the subsequent continuous lubrication of the motor in a low-temperature environment. Preferably, the negative pressure device monitors the pressure in the immersion tank in real time through a pressure sensor, and accurately controls the establishment and recovery rate of the negative pressure.

[0057] S2, the lubricating assembly 50 obtained in step S1 is embedded in the installation cavity 331 of the lubricating seat 33, a grease storage space is formed between the fixed ring 52 and the bottom of the installation cavity 331, and the grease storage space is filled with grease. The installation cavity 331 is a stepped cavity structure, wherein the lubricating assembly 50 is installed in the installation cavity 331 and abuts against the stepped face of the installation cavity 331. An enclosed grease storage space is formed between the lubricating assembly 50 and the bottom of the installation cavity 331, the grease storage space is in contact with the oil felt 51 through the lubricating hole 521, and the grease can be secondarily supplied to the oil felt 51. Preferably, a grease storage space with a thickness of 3 mm-5 mm is formed between the fixed ring 52 and the bottom of the installation cavity 331, and the grease storage space is filled with low-temperature stable grease.

[0058] S3, the support bearing 40 and the retainer assembly 60 are respectively installed to the installation shell 31, the rotating shaft 21 of the rotor mechanism 20 is passed through the retainer assembly 60 and assembled and connected with the support bearing 40, and a grease isolation space is formed between the retainer assembly 60 and the end face of the support bearing 40. Then, the stator mechanism 10 is installed to the installation shell 31, and a wiring process is completed.

[0059] The support bearing 40 is installed to the bearing hole 311 of the bottom wall of the installation shell 31, and the retainer assembly 60 is installed to the retainer hole 312, and the bearing hole 311 and the retainer hole 312 are coaxial and have a stepped structure. The outer wall of the support bearing 40 is tightly connected with the bearing hole 311, the retainer assembly 60 is installed to the installation shell 31, the rotating shaft 21 of the rotor mechanism 20 is passed through the retainer assembly 60 and assembled and connected with the support bearing 40, and a grease isolation space is formed between the retainer assembly 60 and the end face of the support bearing 40.

[0060] The retaining ring assembly 60 comprises a rigid support portion 61 and a resilient portion 62 located at the center, and the resilient portion 62 is elastically connected with the rotating shaft 21 through at least two sealing lips to form a multi-seal structure for blocking the lubricating grease from entering the rotating area of the rotor mechanism 20. The rigid support portion 61 is connected with the mounting shell 31 through a tight fit connection or fastening or a plug-in tight fit connection.

[0061] After the retaining ring assembly 60 is installed on the mounting shell 31, the rotating shaft 21 of the rotor mechanism 20 is inserted into the support bearing 40 through the elastic hole formed by the resilient portion 62. Optionally, a grease blocking space with a thickness of 2-5 mm is formed between the retaining ring assembly 60 and the end face of the support bearing 40, so as to block the lubricating grease and avoid affecting the stability of the motor operation.

[0062] The stator mechanism 10 is installed on the mounting shell 31, and the wiring process is completed. Optionally, a plurality of positioning bosses are uniformly and circumferentially protruded on the outer peripheral wall of the stator mechanism 10, and the inner wall of the mounting shell 31 is provided with corresponding positioning grooves corresponding to the positioning bosses; the positioning bosses of the stator mechanism 10 are embedded into the positioning grooves of the mounting shell 31, and the positioning bosses and the positioning grooves are fit by interference through press fitting. Preferably, an elastic buffer pad made of low-temperature-resistant rubber is pasted to the bottom surface of the positioning groove to improve the shock absorption effect and assembly convenience.

[0063] The wiring process of the stator mechanism 10 and the external circuit is completed, and insulation detection is performed. The interference fit of the positioning bosses and the positioning grooves of the stator mechanism 10 and the setting of the low-temperature-resistant elastic buffer pad not only ensure the coaxiality of the stator assembly, but also absorb the running vibration and improve the overall structural stability.

[0064] S4, the lubricating seat 33 is fixed to the mounting shell 31, and the oil felt 51 faces the support bearing 40 and maintains a predetermined lubricating gap. After the lubricating seat 33 is installed in place, the oil felt 51 and the support bearing 40 have a lubricating gap, which can not only keep the support bearing 40 flexible, but also keep the lubricating reliability. For example, the lubricating gap can be set to 0.1-0.5 mm. Specifically, the lubricating gap can be set to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm. The support bearing 40 is an oil-containing bearing, which can improve the rotation stability of the rotating shaft 21.

[0065] As a preferred, a sealing ring 80 is arranged at the press-fit part of the lubricating seat 33 and the mounting shell 31, and the sealing ring 80 surrounds the lubricating gap to form a ring-shaped elastic seal to avoid leakage at the joint part.

[0066] S5, install dustproof assembly 70 at cover 32 and place in the press-fitting equipment, install mounting shell 31 obtained in S3 to the press-fitting equipment and set opposite to cover 32. Cover 32 and mounting shell 31 are press-fittingly connected by the press-fitting equipment, one end of rotating shaft 21 passes through dustproof assembly 70 and extends out of cover 32.

[0067] Dustproof assembly 70 includes fixing part 71 and silica gel sealing ring 72 installed on fixing part 71, a circle of low-temperature sealing glue is coated in the installation groove of cover 32, dustproof assembly 70 is embedded in the installation groove and is compacted by the pressing block, and is left to solidify for 5-8 min, so that dustproof assembly 70 and cover 32 are fixedly connected.

[0068] Mounting shell 31 is buckled at the opening of cover 32, press-fitting preparation is carried out, one end of rotating shaft 21 passes through cover 32 along dustproof assembly 70. The preset press-fitting area 313 is determined on the outer peripheral wall of mounting shell 31, and the press-fitting area 313 extends from the opening of mounting shell 31 in the axial direction of the motor. For example, the preset press-fitting area 313 is set as an area extending downward from the opening of mounting shell 31 with a width of 20 mm.

[0069] Cover 32 is placed in the positioning base of the tooling and is fixed by the positioning pin, and then mounting shell 31 is placed in the tooling and is positioned by the guide sleeve. The press-fitting equipment is controlled to move downward at a preset press-fitting speed, and press-fitting pressure is applied to cover 32 through mounting shell 31, when the press-fitting equipment is positioned, cover 32 and mounting shell 31 are press-fittingly connected, at this time, one end of rotating shaft 21 passes through dustproof assembly 70 and extends out of cover 32, and the annular lip of silica gel sealing ring 72 is elastically and sealingly connected with rotating shaft 21.

[0070] In order to improve the combination tightness and press-fitting smoothness of mounting shell 31 and cover 32 at the press-fitting position, the press-fitting area 313 is cleaned with anhydrous ethanol cleaning agent, and after natural drying, a lubricant with a thickness of 0.1 mm is coated on the surface of the press-fitting area 313 to improve the press-fitting smoothness.

[0071] S6, the end cover 34 is press-fitted and closed to the other end of the mounting shell 31. The end cover 34 is a thin-walled shell structure, after the lubricating seat 33 is installed to the bottom of the mounting shell 31, the end cover 34 closes the opening of the mounting shell 31, and covers the lubricating seat 33 correspondingly. The end cover 34 and the mounting shell 31 are press-fittingly connected to improve the combination tightness and sealing performance.

[0072] The press-fitting equipment is controlled to move downward and press-fittingly connect cover 32 and the preset press-fitting area 313 of mounting shell 31, and the press-fitting process includes the following steps:

[0073] S51, cover 32 is placed in the positioning base of the tooling and is fixed by the positioning pin, and then mounting shell 31 is placed in the tooling and is positioned by the guide sleeve;

[0074] S52, control the pressing speed of the pressing equipment to be 5 mm / s ~ 10 mm / s, and apply pressure;

[0075] S53, real-time monitoring of the pressure curve of the pressing equipment. The pressing pressure parameters are collected in real time by the high-precision pressure sensor installed on the pressing head, and the displacement parameters of the pressing head are collected by the laser displacement sensor, so that the control system of the pressing equipment can accurately obtain the monitoring data in real time. The control system fits the real-time data of the collected pressure parameters and displacement parameters to form a real-time curve, and compares the real-time curve with the built-in standard pressure displacement curve. The standard curve is generated in advance according to the assembly parameters of different specifications of the motor, and the allowable range of deviation between the real-time curve and the standard curve is set to ± 5%. When the pressure parameters and displacement parameters are within the deviation range, the pressing equipment continues to press; when the pressure parameters and / or displacement parameters exceed the deviation range, the pressing equipment stops pressing.

[0076] The control system fits the real-time data of the collected pressure parameters and displacement parameters to form a real-time curve, including: the pressure sensor and the pressure sensor synchronously collect the pressure parameters and displacement parameters of the corresponding pressing head, and the collected original data is transmitted to the data processing module through the high-speed data transmission line. The data processing module filters the original data to eliminate abnormal noise data caused by environmental vibration, electromagnetic interference and other factors, for example, the Kalman filtering algorithm is used for filtering, and the filtering coefficient is set to 0.05. Then, the processed pressure data and displacement data are associated and matched according to the time sequence to generate a real-time curve, which is displayed in real time in the form of a dynamic curve on the monitoring terminal.

[0077] S54, when the pressing equipment is in place, the pressure is maintained for 5s ~ 10s, so that the cover shell 32 and the mounting shell 31 are tightly matched. The displacement sensor is used to monitor the downward displacement of the pressing head, and when the displacement reaches the preset threshold, it is determined that the pressing position is in place; then the pressure maintaining program is started, and the pressure maintaining time is controlled to be 5s-10s. During the pressure maintaining process, the pressing pressure is maintained stable, so that the mating surface of the cover shell 32 and the mounting shell 31 is fully matched, and the pressing pressure is used to realize the shaping of the mating surface. After the pressure maintaining is completed, the pressing equipment is slowly reset upward to avoid the pulling force generated during the reset to damage the tight fitting structure of the cover shell 32 and the mounting shell 31, and the cover shell 32 and the mounting shell 31 can still maintain a tight and reliable fit in a low temperature environment.

[0078] Further, the mounting shell 31 is formed with a sealing protrusion 314 at the edge of the press-fitting area 313, which can be in the form of a stepped structure or a local protrusion structure. The sealing protrusion 314 is gradually curved from the top to the opening side of the mounting shell 31 to form a tapered surface or a curved surface, which defines the edge of the press-fitting area 313 and smooths the end surface of the cover shell 32, facilitating the positioning of the press-fitting area 313 and the press-fitting of the cover shell 32.

[0079] To further improve the smoothness of the press-fitting of the cover shell 32 and the firmness of the press-fitting part, the cover shell 32 is press-fitted by heating. Optionally, the end part of the cover shell 32 is heated to 130-155°C by induction heating, and the temperature is maintained for 1-2.5 minutes.

[0080] In a specific embodiment, the cover shell 32 is placed in the positioning base of the tooling and fixed by the positioning pin, and then the mounting shell 31 is placed in the tooling and positioned by the guide sleeve. The press-fitting equipment is controlled to move downward at a press-fitting speed of 8 mm / s, and a pressure of 15 kN is applied to the cover shell 32. At the same time, the pressure parameter is collected by the pressure sensor mounted on the press head, and the displacement parameter of the press head is collected by the displacement sensor. The pressure parameter and the displacement parameter are compared with the built-in standard pressure-displacement curve, and the deviation range is set to ±5%. When the press-fitting equipment is positioned, the end part of the cover shell 32 is gradually unfolded along the press-fitting area 313 and adheres to the sealing protrusion 314. The pressure is maintained for 8 seconds, and the press-fitting and tight-fitting connection of the cover shell 32 and the mounting shell 31 is completed.

[0081] The press-fitting process of the mounting shell 31 and the cover shell 32 uses positioning tooling, precise speed control, and real-time monitoring of the pressure curve, and cooperates with the sealing protrusion 314 structure and the induction heating assembly process, which greatly improves the fitting accuracy of the two, and still maintains a tight fit after material shrinkage in a low-temperature environment, avoiding looseness.

[0082] As shown in FIGS. Figure 2 and Figure 3 In an embodiment, the rotating shaft 21 is provided with an annular oil return groove 211 and at least one branch oil passage 212, and the branch oil passage 212 communicates with the annular oil return groove 211. The annular oil return groove 211 is located in the grease isolation space formed in step S3, and the oil outlet of the branch oil passage 212 extends to the end of the rotating shaft 21. The annular oil return groove 211 and the at least one branch oil passage 212 are integrally designed on the rotating shaft 21 to form an integrated lubrication circulation structure for oil collection by the annular oil return groove 211 and oil return by the branch oil passage 212. The oil inlet of the branch oil passage 212 communicates with the annular oil return groove 211, the oil outlet of the branch oil passage 212 extends to the end of the rotating shaft 21, and efficient recovery and directional drainage of the lubricating grease are achieved.

[0083] The annular oil return groove 211 is annularly recessed on the outer circumferential wall of the rotating shaft 21 and is located within the range of the grease separation space formed in step S3. The lubricating grease overflowing from the support bearing 40 during operation is quickly collected into the annular oil return groove 211 under the joint action of centrifugal force and gravity, avoiding the sealing blockage or lubrication failure caused by the accumulation of lubricating grease in the grease separation space, and at the same time, the grease separation space provides a stable oil collection environment for the annular oil return groove 211.

[0084] The branch oil path 212 adopts an inclined guide hole structure, the oil inlet end of the branch oil path 212 is arranged at the lowest part of the annular oil return groove 211, and the oil outlet of the branch oil path 212 extends to the non-matching area of the end of the rotating shaft 21. The branch oil path 212 utilizes the natural oil return gradient formed by the inclination angle to cooperate with the centrifugal force during the operation of the rotating shaft 21, so as to quickly return the lubricating grease collected in the annular oil return groove 211 to the oil felt 51 area at the end of the rotating shaft 21, realizing the recycling of the lubricating grease.

[0085] The oil path structure is integrally machined with the rotating shaft 21, without the need for additional pipeline assembly, which simplifies the assembly process, avoids the sealing hidden danger caused by pipeline connection, improves the structural strength of the rotating shaft 21, adapts to the change of material mechanical properties in low temperature environment, and prevents stress concentration of the rotating shaft 21 caused by additional holes.

[0086] Before assembling the rotor mechanism 20, a layer of lubricating grease is evenly applied on the inner walls of the annular oil return groove 211 and the branch oil path 212 to form an initial lubricating film, further reducing the frictional resistance during low temperature start-up.

[0087] It should be understood that the present application is not limited to the precise construction which has been described above and illustrated in the accompanying drawings, and that various modifications and changes can be made without departing from the scope thereof. It is intended that the application encompass any and all variations, uses, or adaptations of the application which follow, in general, the principles of the application and include uses of the application in the technical field disclosed herein, and to adapted uses of those that are obvious to those skilled in the art.

Claims

1. A method for assembling a motor for cryogenic equipment, the motor comprising a housing, a rotor mechanism, a stator mechanism, and a support bearing, characterized in that, The shell comprises an installation shell, a cover shell and a lubricating seat, and the assembling method comprises the following steps: S1, cutting and embedding the oil felt into the fixing groove of the fixing ring to form a lubricating assembly, so that the oil felt is flush with or slightly exceeds the opening of the fixing groove; a plurality of lubricating holes are arranged at the bottom of the fixing groove; the lubricating assembly is immersed in lubricating grease until it is completely infiltrated, and then it is taken out and drained of surface grease; S2, embedding the lubricating assembly obtained in step S1 into the installation cavity of the lubricating seat to form a grease storage space between the fixing ring and the bottom of the installation cavity, and filling the grease storage space with lubricating grease; S3, installing the support bearing and the retainer assembly to the installation shell respectively, assembling the rotating shaft of the rotor mechanism through the retainer assembly and connecting it with the support bearing, so as to form a grease separation space between the retainer assembly and the end face of the support bearing; then installing the stator mechanism on the installation shell and completing the wiring process; S4, fixing the lubricating seat to the installation shell, and the oil felt faces the support bearing and maintains a predetermined lubrication gap; S5, installing a dustproof assembly at the cover shell and placing it on a press fitting device, installing the installation shell obtained in S3 on the press fitting device and arranging it opposite to the cover shell; tightly fitting and connecting the cover shell and the installation shell by the press fitting device, so that one end of the rotating shaft passes through the dustproof assembly and extends out of the cover shell; S6, pressing and closing the other end of the installation shell with an end cover; An annular oil return groove and at least one branch oil path are arranged on the rotating shaft, and the branch oil path communicates with the annular oil return groove; the annular oil return groove is located in the grease separation space formed in step S3, and the oil outlet of the branch oil path extends to the end of the rotating shaft; before assembling the rotor mechanism, lubricating grease is applied to the inner walls of the annular oil return groove and the branch oil path.

2. The method of assembly of claim 1, wherein, The tightly fitting and connecting of the cover shell and the installation shell by the press fitting device comprises: determining a predetermined press fitting area on the outer peripheral wall of the installation shell; cleaning the press fitting area with a cleaning agent, and drying after cleaning is completed; applying a lubricant of a predetermined thickness on the surface of the press fitting area; controlling the press fitting device to move downward and press fitting connect the cover shell and the predetermined press fitting area of the installation shell.

3. The method of assembly of claim 2, wherein, The controlling of the press fitting device to move downward and press fitting connect the cover shell and the predetermined press fitting area of the installation shell comprises: placing the cover shell into the positioning base of the tool and limiting and fixing it through the positioning pin, and then placing the installation shell into the tool and positioning it through the guide sleeve; controlling the press fitting speed of the press fitting device to be 5 mm / s ~ 10 mm / s, and applying pressure; real-time monitoring the pressure curve of the press fitting device; when the press fitting device is in place, maintaining the pressure for 5 s ~ 10 s, so that the cover shell and the installation shell are tightly fitted.

4. The method of assembly of claim 3, wherein, The real-time monitoring of the pressure curve of the press fitting device comprises: collecting pressure parameters through the sensor installed on the press head; collecting displacement parameters of the press head through the displacement sensor; comparing the pressure parameters and the displacement parameters with the built-in standard pressure displacement curve; when the pressure parameters and the displacement parameters are within the deviation range, continue to press fit; when the pressure parameters and / or the displacement parameters exceed the deviation range, stop press fitting.

5. The method of assembly of claim 2, wherein, The mounting shell forms a sealing protrusion at the edge of the press-fitting area, and the sealing protrusion has a height of 3-5 mm; The press-fitting connection of the cover shell and the preset press-fitting area of the mounting shell comprises the following steps: heating the end of the cover shell to 120-150 °C by induction heating, keeping warm for 2-3 min, and then press-fitting the cover shell into the press-fitting area until the end of the cover shell gradually expands along the sealing protrusion and is attached.

6. The method of assembly of claim 1, wherein, The step of immersing the lubricating assembly into the lubricating grease to complete the immersion comprises the following steps: Placing a plurality of lubricating assemblies into the lubricating grease in the immersion box; Sending the immersion box into a negative pressure device, controlling the immersion box to be in a negative pressure environment, controlling the immersion environment temperature to be 0-5 °C, and standing still for 10-20 min under the condition; Controlling the negative pressure device to slowly recover to standard atmospheric pressure, and then taking out the lubricating assembly from the immersion box.

7. The method of assembly of claim 1, wherein, The support bearing is an oil-containing bearing.

8. The method of assembly of claim 1, wherein, The dustproof assembly comprises a fixing member and a silica gel sealing ring mounted on the fixing member, an inner ring of the silica gel sealing ring is provided with an annular lip, and the annular lip is in interference fit with the rotating shaft; when the dustproof assembly is mounted, a circle of sealing glue is coated in the mounting groove of the cover shell, the dustproof assembly is embedded in the mounting groove and compacted, and the cover shell and the mounting shell are press-fitted after standing still for 5-8 min for solidification.

9. The method of assembly of claim 1, wherein, The outer peripheral wall of the stator mechanism is uniformly provided with at least three positioning bosses in the circumferential direction, and the inner wall of the mounting shell is provided with adapted positioning grooves corresponding to the positioning bosses; When the stator mechanism is assembled, the positioning bosses of the stator mechanism are aligned with the positioning grooves of the mounting shell and are embedded, so that the positioning bosses and the positioning grooves are in interference fit.

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