A bearing precision manufacturing process based on multi-physical field collaborative regulation

Abstract

The application discloses a kind of bearing precision manufacturing process based on multi-physical field coordination control, belongs to bearing manufacturing technical field, specific steps include: cutting to the bearing inner ring and outer ring of two sizes of forgings is carried out, the gradient heating of partition and staged cooling are carried out to bearing inner ring and outer ring respectively;The bearing inner ring and outer ring after cooling are independently processed, then the bearing inner ring and outer ring are combined cover;Sealing element is pretreated, improves sealing element surface characteristics, simultaneously ensures lubricating grease performance stability by rheological control, then quantitative grease injection is carried out;The deformation amount and deformation rate of sealing lip edge are captured in real time by high-speed machine vision system, constructs two-dimensional deformation cloud picture, according to the data captured, completes the gland work of sealing element. By organically combining electromagnetic field, thermal field, force field and the like multi-physical field, the accurate control of bearing manufacturing whole process is realized.

Description

Technical Field

[0001] This invention relates to a precision bearing manufacturing process based on multi-physics field coordinated control, belonging to the field of industrial robot technology. Background Technology

[0002] As a core component of industrial robots, bearings' precision directly affects the stability and lifespan of the equipment. In particular, bearings used under special operating conditions have a significant impact on the overall performance of the industrial robot they are paired with. The bearing material, heat treatment process, machining process, and the method of grease injection and gland assembly are all important factors in achieving excellent bearing performance under special operating conditions.

[0003] In terms of heat treatment, conventional integral quenching is typically used for bearing rings. The bearing rings are first heated to approximately 840℃ and held at that temperature for a certain time to allow the carbides to dissolve uniformly. This is followed by quenching and cooling, and finally low-temperature tempering. For grease injection, ordinary grease injection equipment is used to inject grease into the bearing, with the amount and location controlled manually based on experience. For sealing, traditional rubber seals are installed at the ends of the inner and outer rings to prevent grease leakage and the intrusion of external impurities. However, the above approach has the following shortcomings in practical use:

[0004] The heat treatment process lacks specificity: While conventional integral quenching is suitable for bearings under general operating conditions, it is insufficient for special conditions such as high-impact, high-load environments with drastic temperature changes. Under such conditions, the internal structure of the bearing rings is prone to inhomogeneity after this process, resulting in an inability to achieve optimal matching of hardness and toughness in different parts, thus affecting the bearing's fatigue resistance and service life.

[0005] The precision and reliability of grease injection methods are poor: relying on manual experience to control the amount and location of grease cannot ensure that the grease is evenly and accurately distributed to all critical parts of the bearing under special operating conditions. In special operating conditions such as high-speed rotation and high load, uneven grease injection can easily cause insufficient lubrication in some areas, leading to problems such as accelerated wear and increased temperature, which seriously affects the normal operation of the bearing.

[0006] The sealing structure has poor adaptability: Traditional rubber seals have many drawbacks under special working conditions. For example, in high-temperature environments, rubber is prone to aging and loss of elasticity, leading to a decrease in sealing performance and an increased risk of grease leakage; in high-dust environments, fine dust particles can easily embed into the sealing surface of the rubber seal, damaging the sealing effect and allowing external impurities to enter the bearing, accelerating bearing wear. Summary of the Invention

[0007] The purpose of this invention is to provide a precision bearing manufacturing process based on multi-physics field synergistic control, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] Compared to existing technologies, this invention provides a precision bearing manufacturing process based on multi-physics field synergistic control, the specific steps of which include:

[0010] S1. The inner and outer rings of the bearing are obtained by cutting the forgings of two sizes. The inner and outer rings of the bearing are then subjected to gradient heating and staged cooling in separate zones.

[0011] S2. The inner and outer rings of the bearing are machined independently after cooling. Then the inner and outer rings of the bearing are assembled. The dimensional data is collected in real time by a laser diameter measuring instrument and the grinding allowance is automatically calculated.

[0012] S3. Pre-treat the seal to improve its surface properties. At the same time, ensure the stability of the grease performance through rheological regulation. Then, perform quantitative grease injection. Before grease injection, vacuum the seal. During grease injection, pre-compress the sealing ring. After grease injection, release the vacuum.

[0013] S4. The deformation amount and rate of the sealing lip are captured in real time by a high-speed machine vision system, and a two-dimensional deformation cloud map is constructed. Based on the captured data, the sealing capping work is completed.

[0014] Preferably, in step S1, the inner and outer rings of the bearing are 3D scanned to divide the raceway area, end face area and chamfer area, and induction coils of different frequencies are configured in the raceway area, end face area and chamfer area respectively. By utilizing the electromagnetic field coupling effect, dynamic heat distribution is achieved through the phase difference of the coils. The temperature of the zones is monitored in real time by an infrared thermal imaging system. When the temperature deviation is ≥5℃, the coil power is dynamically reduced.

[0015] Preferably, when heating the inner and outer rings of the bearing, a gradient heating method is used, with a heating range of 80℃-850℃. A heat preservation point is set for every 10℃ increase, and the heat preservation time is 3-8 minutes.

[0016] When performing staged cooling on the inner and outer rings of the bearing, hot oil is first circulated to slow down the cooling process. The hot oil temperature is 130-170℃, the flow rate is 2-4m / s, and this is maintained for 20-35s. The buffering properties of the hot oil are used to reduce the temperature gradient between the inner and outer rings during the initial cooling phase. Then, high-speed air cooling at 18m / s is switched to complete the phase transformation. The rapid cooling causes the microstructure of the inner and outer rings of the bearing to transform into the desired martensitic structure.

[0017] Preferably, in S2, the machining process of the bearing inner ring includes: end face grinding, outer cylindrical grinding, ultra-precision grinding of the outer cylindrical ring, inner groove grinding, inner cylindrical grinding, and ultra-precision grinding of the outer groove.

[0018] The machining process for the outer ring of a bearing includes: end face grinding, outer cylindrical grinding, outer groove grinding, and outer groove ultra-precision grinding.

[0019] Preferably, in step S2, the dual-station assembly machine automatically adjusts the fixture spacing based on the calculated clearance value, marks a unique pairing number after pairing is completed, and the clearance accuracy of the inner and outer rings of the bearing after assembly is ≤0.005mm.

[0020] Preferably, in step S3, when pre-treating the seal, an atmospheric low-temperature plasma treatment machine is used to scan the seal for 25-35 seconds to introduce -OH / -COOH groups. The seal is then detected in real time by a contact angle detector. If the seal does not meet the standard, it is re-treated for 5-10 seconds.

[0021] Preferably, in S3,

[0022] Before quantitative grease injection, the viscosity and yield stress of the grease are tested using an online rotational rheometer. When the grease viscosity is >500 Pa·s, the electromagnetic induction heater is activated to adjust the grease temperature to 35℃.

[0023] When performing quantitative grease injection, a triple compensation mechanism of loss-of-weight metering, rheological compensation, and environmental compensation is adopted. Among them, the grease injection nozzle of the grease injection machine is equipped with an elastic sealing ring and a vacuum adsorption pipeline.

[0024] Preferably, in step S4, the system constructs a two-dimensional deformation cloud map based on the captured data to visually display the deformation distribution;

[0025] When the deformation of the sealing lip is less than 80% of the target value, a constant-speed gland pressing method should be used.

[0026] When the deformation of the sealing lip is greater than or equal to 80% of the target value, switch to constant force gland with adaptive displacement compensation.

[0027] Preferred options also include:

[0028] S5. After grease injection and capping, place the bearing in an ultrasonic cleaning tank and use ultrafiltered deionized water as the cleaning medium to remove trace amounts of grease residue and tiny particles from the bearing surface.

[0029] S6. After cleaning and drying, a fluorinated carbon (CFx) coating is deposited on the bearing surface.

[0030] Preferably, in S6, the thickness of the fluorinated carbon CFx coating is 10-20 nanometers.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] By dividing the inner and outer rings of the bearing into zones for gradient heating and staged cooling, combined with 3D scanning to divide the area, configuring induction coils of different frequencies, and real-time monitoring by an infrared thermal imaging system, precise control of the heat treatment process of the inner and outer rings of the bearing is achieved. Temperature uniformity is significantly improved, residual stress is reduced, and deformation is reduced, thereby improving the dimensional accuracy and mechanical properties of the bearing.

[0033] By using a laser diameter measuring instrument to collect dimensional data in real time and automatically calculate the grinding allowance, and with the precise adjustment of the double-station assembly machine, the clearance accuracy of the inner and outer rings of the bearing after assembly is ≤0.005mm, which ensures the assembly accuracy of the bearing and improves the rotation accuracy and stability of the bearing.

[0034] Atmospheric low-temperature plasma treatment of the seals improves their surface properties and enhances the bonding force between the seals and the bearings. A triple compensation mechanism is used during the grease injection process to ensure grease injection accuracy. During the gland pressing process, real-time monitoring and intelligent control through a high-speed machine vision system enables precise deformation control of the sealing lip, improving sealing performance and enhancing the waterproof rating of the bearings.

[0035] This invention organically combines multiple physical fields such as electromagnetic field, thermal field, and force field. Through the coordinated regulation of these physical fields, it achieves precise control over the entire bearing manufacturing process, comprehensively improving the manufacturing precision and quality of bearings and meeting the manufacturing requirements of high-precision bearings. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0037] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] This invention provides a technical solution:

[0040] A precision bearing manufacturing process based on multi-physics field synergistic control includes the following steps:

[0041] S1. The inner and outer rings of the bearing are obtained by cutting the forgings of two sizes. The inner and outer rings of the bearing are then subjected to gradient heating and staged cooling in separate zones.

[0042] S2. The inner and outer rings of the bearing are machined independently after cooling. Then the inner and outer rings of the bearing are assembled. The dimensional data is collected in real time by a laser diameter measuring instrument and the grinding allowance is automatically calculated.

[0043] S3. Pre-treat the seals to improve their surface properties. Simultaneously, ensure stable grease performance through rheological control. This involves controlling the rheological parameters of the grease to ensure uniform filling and long-term stability within the sealing structure. Then, perform quantitative grease injection. Before injection, the vacuum system is evacuated to -0.05 MPa. During injection, the sealing ring is pre-pressurized to 0.08 MPa to form an initial seal with the bearing grease inlet. Simultaneously, vacuum adsorption eliminates gaps, further enhancing the sealing effect. After injection, the vacuum is released, ensuring an effective seal is formed during the injection process, preventing grease leakage and contamination of the sealing surface. This reduces the grease overflow rate to ≤0.01%, improving injection accuracy and cleanliness.

[0044] S4. The deformation amount and rate of the sealing lip are captured in real time by a high-speed machine vision system, and a two-dimensional deformation cloud map is constructed. Based on the captured data, the sealing capping work is completed.

[0045] Furthermore, in S1, the inner and outer rings of the bearing are 3D scanned to divide the raceway area, end face area and chamfer area. Induction coils of different frequencies are configured in the raceway area, end face area and chamfer area respectively. By utilizing the electromagnetic field coupling effect, dynamic heat distribution is achieved through the phase difference of the coils. The temperature of each zone is monitored in real time by an infrared thermal imaging system. When the temperature deviation is ≥5℃, the coil power is dynamically reduced.

[0046] Specifically, when heating the inner and outer rings of the bearing, a gradient heating method is used, with a heating range of 80℃-850℃. A heat preservation point is set for every 10℃ increase, and the heat preservation time is 3-8 minutes.

[0047] When performing staged cooling on the inner and outer rings of the bearing, hot oil is first circulated to slow down the cooling process. The hot oil temperature is 130-170℃, the flow rate is 2-4m / s, and this is maintained for 20-35s. The buffering properties of the hot oil are used to reduce the temperature gradient between the inner and outer rings during the initial cooling phase. Then, high-speed air cooling at 18m / s is switched to complete the phase transformation. The rapid cooling causes the microstructure of the inner and outer rings of the bearing to transform into the desired martensitic structure.

[0048] Furthermore, in S2, the machining processes for the bearing inner ring include: end face grinding, outer cylindrical grinding, ultra-precision grinding of the outer cylindrical ring, inner groove grinding, inner cylindrical grinding, and ultra-precision grinding of the outer groove.

[0049] The machining process for the outer ring of a bearing includes: end face grinding, outer cylindrical grinding, outer groove grinding, and outer groove ultra-precision grinding.

[0050] Specifically, the machining of the bearing outer ring includes:

[0051] The outer ring is clamped by an electromagnetic chuck, and the end face is ground by a precision surface grinder to control the flatness to ≤0.002mm, ensuring the positioning accuracy of subsequent processes. After grinding, the end face runout is detected, and workpieces with a deviation exceeding 0.003mm are automatically rejected.

[0052] The outer diameter is precision ground using a forming grinding wheel with diamond binder, achieving a dimensional accuracy of IT4 grade and a roundness of ≤0.001mm;

[0053] A three-stage processing technique is adopted, combined with an elliptical vibration trajectory grinding wheel, to eliminate surface waviness, ultimately achieving Ra≤0.4μm;

[0054] The inner groove is machined by forming a grinding wheel with a curvature radius tolerance of ±0.01mm; the raceway is ultra-precisioned using an air-floating centered nano-composite abrasive oilstone with a surface roughness Ra≤0.1μm, and the groove position accuracy and parallelism to the end face ≤0.005mm.

[0055] The machining of the bearing inner ring includes:

[0056] Using a chuck to rigidly clamp the inner ring, the flatness of the end face of the high-precision surface grinder is ≤0.002mm; the outer diameter is ground by a high-precision centerless grinder, with dimensional accuracy reaching IT5 level and roundness ≤0.0015mm.

[0057] The internal hole is ground using an internal grinding head, with compound motion machining and dynamic pressure adjustment. The surface roughness Ra of the internal hole is ≤0.05μm and the roundness is ≤0.002mm.

[0058] The inner groove raceway is precision ground using a shaped grinding wheel with a symmetry of ≤0.005mm; the raceway is ultra-precision ground using an air-float centered nanocomposite abrasive oilstone with Ra≤0.1μm, and the groove position accuracy and parallelism to the end face are ≤0.005mm.

[0059] Furthermore, in S2, the dual-station assembly machine automatically adjusts the fixture spacing based on the calculated clearance value, and marks a unique pairing number after pairing is completed. The clearance accuracy of the inner and outer rings of the bearing after assembly is ≤0.02mm.

[0060] Furthermore, in S3, during the pretreatment of the seal, an atmospheric low-temperature plasma treatment machine is used to scan the seal for 25-35 seconds, introducing -OH / -COOH groups. The contact angle is detected in real time by a contact angle detector. If the seal does not meet the standard, it is treated again for 5-10 seconds. Through plasma activation treatment, -OH / -COOH groups are introduced into the surface of the seal, reducing the contact angle from ≥60° to ≤30° and increasing the peel strength by 40%. This significantly improves the wettability and adhesion of the seal surface, which helps to improve the sealing effect and the bonding strength between the seal and the bearing.

[0061] In one embodiment,

[0062] The plasma treatment parameters, including power, argon flow rate, and time, were optimized using orthogonal experimental design, with the surface energy γ of the sealing component and the peel strength τ as evaluation indicators. The experimental design is as follows:

[0063] Power range: 200-400W;

[0064] Argon flow rate: 5-20 L / min;

[0065] Power (W) Argon flow rate (L / min) Time (s) Surface energy (mN / m) Peel strength (N / mm) Hardness (Shore A) 300 15 30 75 40 62 250 15 30 68 35 64 350 15 30 72 38 60 300 10 30 65 32 65 300 20 30 70 37 63

[0066] analyze,

[0067] Experimental results show that when the power is 300W, the argon flow rate is 15L / min, and the time is 30s, the surface energy γ of the seal increases from 42mN / m to 75mN / m, the peel strength τ increases from 28N / mm to 40N / mm, and the Shore A hardness only decreases by 3°, that is, from 65° to 62°, without thermal damage.

[0068] Furthermore, in S3, when rheologically controlling the grease:

[0069] Before quantitative grease injection, an online rotational rheometer is used to detect the grease viscosity and yield stress. When the grease viscosity is >500 Pa·s, the electromagnetic induction heater is activated to adjust the grease temperature to 35℃. Specifically, the online rotational rheometer, with a shear rate of 100-1000 s⁻¹, detects the grease viscosity η and yield stress τ0 in real time. When η >500 Pa·s, i.e., at low temperature, the electromagnetic induction heater is activated to control the temperature at 35±2℃, so that η is adjusted to the range of 300-400 Pa·s. When the ambient humidity H >60%, hot air at 40℃ and a wind speed of 1 m / s is blown into the grease nozzle to prevent the grease from absorbing moisture. By detecting the grease viscosity and yield stress in real time and combining the temperature and humidity data for dynamic adjustment, the grease is ensured to always be kept in the optimal rheological state. This helps to improve the grease injection accuracy and reduce the impact of environmental factors on the grease injection process.

[0070] When performing quantitative grease injection, a triple compensation mechanism of loss-of-weight metering, rheological compensation, and environmental compensation is adopted. Among them, the grease injection nozzle of the grease injection machine is equipped with an elastic sealing ring and a vacuum adsorption pipeline.

[0071] Among them, the triple compensation is triggered in order of priority: "environmental layer, rheological layer, and base layer" to avoid oil overflow caused by high humidity or high viscosity.

[0072] Environmental layer, i.e., high humidity H>60%: activate vacuum adsorption, pressure 0.08MPa, vacuum degree -0.05MPa, to compensate for volume expansion caused by moisture absorption of grease;

[0073] Rheological layer, i.e. η > 500 Pa·s: screw speed decreases by 5% / 100 Pa·s, that is, when η = 600 Pa·s, the speed = reference speed × 0.95;

[0074] The base layer, i.e., weightless metering, provides real-time feedback on the amount of grease injected, with an error of ±0.005g.

[0075] Experimental tests showed that when η = 300-500 Pa·s, the error in grease injection volume after speed compensation was ≤ ±0.003g. In one embodiment, when the reference speed was 1500 rpm, η = 400 Pa·s, the actual speed was 1500 × 0.95 = 1425 rpm, the grease injection volume was the reference volume × (1 - 0.05) = 0.95 times, and the error was ≤ ±0.003g.

[0076] In S4, a high-speed machine vision system is integrated into the capping station. The frame rate is 200fps and the accuracy reaches ±0.002mm. The system captures the deformation amount δ and deformation rate v of the sealing lip in real time and feeds back the data every 5ms. Based on the captured data, the system constructs a two-dimensional deformation cloud map to intuitively display the deformation distribution.

[0077] When δ < 80% of the target value, a constant speed capping is used. At this time, the speed is 0.5 mm / s and the pressure F ≤ 50 N.

[0078] When δ≥80% of the target value, switch to constant force pressure cover, pressure F=60±2N, and displacement adaptive compensation, that is, active compensation is used when the error is large, and switch to stable force control when the error is close to the critical value to prevent overcompensation from causing oscillation;

[0079] Specifically, by using a high-speed machine vision system to capture the deformation amount and rate of the sealing lip in real time and constructing a two-dimensional deformation cloud map, precise real-time data is provided for force-position-deformation coordinated control. This method allows the gland sealing process to be precisely adjusted according to the actual deformation, significantly improving the accuracy and consistency of the gland sealing.

[0080] During image acquisition, the calibration method of the machine vision system adopts the Zhang Zhengyou calibration method. A 100×100mm checkerboard calibration board is used to acquire 20 images under the conditions of object distance of 300mm and focal length of 25mm. The camera intrinsic parameters are calculated as follows: focal length fx=5000 pixels, fy=5000 pixels; principal point cx=1500 pixels, cy=1500 pixels; pixel accuracy=0.004mm / pixel.

[0081] Canny edge detection is used with a low threshold of 50 and a high threshold of 150. Combined with the grayscale centroid method, the sub-pixel coordinates of the sealing lip edge are calculated with an accuracy of ±0.002mm. When the deformation δ=0.05mm, the measurement error is ≤±0.002mm.

[0082] A precision bearing manufacturing process based on multi-physics field synergistic control also includes:

[0083] S5. After grease injection and capping, place the bearing in a specially designed ultrasonic cleaning tank. This cleaning tank uses a high-frequency ultrasonic generator of 40-60kHz and a low-power ultrasonic generator of 50-100W, and uses ultra-filtered deionized water as the cleaning medium. Ultrasonic waves can generate cavitation effect at the microscale, effectively removing trace amounts of grease residue and tiny particles from the bearing surface without damaging the bearing itself. The cleaning process lasts 30-60 seconds, which can be adjusted according to the actual degree of contamination.

[0084] S6. After cleaning, the bearing is dried and then a 10-20 nanometer thick fluorinated carbon CFx coating is deposited on the bearing surface using plasma-assisted chemical vapor deposition (PECVD). This nano-coating has extremely low surface energy and excellent oleophobic and hydrophobic properties, which can effectively prevent the adhesion of trace contaminants that may occur later. The PECVD process is carried out at a low temperature of <100°C, which will not affect the mechanical properties and dimensional accuracy of the bearing.

[0085] Specifically, ultrasonic cleaning technology effectively removes trace contaminants, while the nano-antifouling coating further improves the ability to maintain the cleanliness of the bearing surface. Ultrasonic cleaning utilizes the microbubble collapse effect generated by sound waves in liquids to remove tiny contaminants without damaging the bearing surface. The nano-coating, by changing the surface energy properties, makes it difficult for potential contaminants to adhere to the bearing surface.

[0086] It should be noted that, for further illustration, the following comparative examples are provided:

[0087] Comparative Example 1

[0088] S1. Select two forgings of suitable size and obtain the bearing inner ring and outer ring by cutting. Perform 3D scanning on the bearing inner and outer rings to accurately divide the raceway area, end face area and chamfer area. Configure an induction coil with frequency f1 in the raceway area, an induction coil with frequency f2 in the end face area and an induction coil with frequency f3 in the chamfer area, where f1 > f2 > f3. Turn on the induction coils and use the electromagnetic field coupling effect to achieve dynamic heat distribution through the phase difference of the coils. At the same time, start the infrared thermal imaging system 4 to monitor the temperature of each zone in real time. When the temperature deviation of a certain zone is detected to be ≥5℃, the system automatically issues a command to dynamically reduce the power of the induction coil in that area.

[0089] The bearing's inner and outer rings were heated using a gradient heating method, starting at 80°C. A holding period of 5 minutes was set for every 10°C increase, until the temperature reached 850°C. After heating, staged cooling was performed. First, hot oil at 150°C and a flow rate of 3 m / s was introduced and held for 25 seconds to reduce the initial temperature gradient using the buffering properties of the hot oil. Then, high-speed air cooling at 18 m / s was switched to complete the phase transformation, converting the microstructure of the bearing's inner and outer rings into the desired martensitic structure.

[0090] S2. Perform end face grinding, outer cylindrical grinding, ultra-precision grinding of the outer cylindrical surface, inner groove grinding, inner cylindrical grinding, and ultra-precision grinding of the outer groove on the cooled bearing inner ring; perform end face grinding, outer cylindrical grinding, outer groove grinding, and ultra-precision grinding of the outer groove on the bearing outer ring.

[0091] The machined bearing inner and outer rings are placed on a double-station assembly machine. A laser diameter gauge is activated to collect real-time dimensional data of the bearing inner and outer rings and automatically calculates the grinding allowance. Based on the calculated clearance value, the double-station assembly machine automatically adjusts the fixture spacing to complete the pairing of the bearing inner and outer rings and marks each pair with a unique pairing number. After assembly, the clearance accuracy is checked, and the result is 0.018mm, meeting the requirement of ≤0.02mm.

[0092] S3. Place the seal in an atmospheric low-temperature plasma treatment machine and perform a 30-second scanning treatment to introduce -OH / -COOH groups onto the surface of the seal. Detect the surface properties of the seal in real time using a contact angle detector. If the surface properties do not meet the standards, perform an additional 8-second treatment.

[0093] Before quantitative grease injection, the viscosity and yield stress of the grease were tested using an online rotational rheometer 10. It was found that the viscosity of the grease was 600 Pa·s > 500 Pa·s. The electromagnetic induction heater 11 was then activated to adjust the temperature of the grease to 35°C.

[0094] The grease injection machine is started to inject grease in a quantitative manner. Before injection, the injection area is evacuated through the vacuum adsorption pipeline. During injection, the elastic sealing ring is pre-compressed. After injection, the vacuum is released. During the injection process, a triple compensation mechanism of weight loss metering, rheological compensation, and environmental compensation is adopted to ensure the accuracy of grease injection.

[0095] S4. Activate the high-speed machine vision system to capture the deformation amount and deformation rate of the sealing lip in real time, and construct a two-dimensional deformation cloud map. When the deformation amount of the sealing lip is less than 80% of the target value, a constant speed sealing is adopted with a sealing speed of 0.5 mm / s. When the deformation amount of the sealing lip is greater than or equal to 80% of the target value, switch to constant force sealing with a sealing force of 60 N and adaptive displacement compensation to complete the sealing work of the seal.

[0096] S5. Place the bearing after grease injection and capping in an ultrasonic cleaning tank, add ultrafiltered deionized water as the cleaning medium, turn on the ultrasonic cleaning function to remove trace amounts of grease residue and tiny particles from the bearing surface.

[0097] S6. After cleaning, the bearing is dried and then a 15-nanometer thick fluorinated carbon (CFx) coating is formed on the bearing surface through a deposition process.

[0098] Comparative Example 2

[0099] S1 is basically the same as Comparative Example 1, except that: during the gradient heating process, the holding time is 3 minutes for every 10°C increase; during the staged cooling, the hot oil temperature is 130°C, the flow rate is 2 m / s, and it is held for 35 seconds.

[0100] S2 is basically the same as Comparative Example 1, and the clearance accuracy test result after assembly is 0.015mm.

[0101] S3 is basically the same as Comparative Example 1, except that: the scanning time of the atmospheric low-temperature plasma treatment machine for the sealing component is 25s, and an additional 5s is added if the standard is not met; the viscosity of the lubricating grease is 450Pa・s < 500Pa・s, so there is no need to start the electromagnetic induction heater 11.

[0102] S4 is basically the same as Comparative Example 1.

[0103] S5, same as Comparative Example 1.

[0104] S6 is basically the same as Comparative Example 1, except that the thickness of the fluorinated carbon (CFx) coating is 10 nanometers.

[0105] Comparative Example 3

[0106] S1 is basically the same as Comparative Example 1, except that: during the gradient heating process, the holding time is 8 minutes for every 10°C increase; during the staged cooling, the hot oil temperature is 170°C, the flow rate is 4 m / s, and it is held for 20 seconds.

[0107] S2 is basically the same as Comparative Example 1, and the clearance accuracy test result after assembly is 0.020mm.

[0108] S3 is basically the same as Comparative Example 1, except that: the scanning time of the atmospheric low-temperature plasma treatment machine for the sealing part is 35s, and 10s is added if the standard is not met; the viscosity of the lubricating grease is 700Pa・s > 500Pa・s, and the electromagnetic induction heater 11 is started to adjust the temperature of the lubricating grease to 35℃.

[0109] S4 is basically the same as Comparative Example 1.

[0110] S5, same as Comparative Example 1.

[0111] S6 is basically the same as Comparative Example 1, except that the thickness of the fluorinated carbon (CFx) coating is 20 nanometers.

[0112] Comparative Example Insulation time Hot oil temperature / flow rate / holding time Temperature uniformity Residual stress Deformation Comparative Example 1 5 min / per 10℃ 150℃ / 3m / s / 25s ±5℃ ≤150MPa ≤0.008mm Comparative Example 2 3 min / per 10℃ 130℃ / 2m / s / 35s ±6℃ ≤160MPa ≤0.009mm Comparative Example 3 8 min / per 10℃ 170℃ / 4m / s / 20s ±4.5℃ ≤140MPa ≤0.007mm

[0113] analyze,

[0114] The effect of heat preservation time:

[0115] Extending the heat preservation time can improve temperature uniformity because the longer heat diffusion time reduces the temperature difference between zones, but it will increase energy consumption.

[0116] Shortening the heat preservation time reduces the temperature uniformity to ±6℃ and slightly increases the residual stress, making it suitable for scenarios with slightly lower precision requirements but high-efficiency production.

[0117] The influence of hot oil cooling parameters:

[0118] High-temperature, high-speed hot oil can accelerate heat exchange during the initial cooling stage. Combined with a short holding time of 20 seconds, the residual stress is reduced to 140 MPa, while the deformation is minimized. This is attributed to the rapid buffer cooling reducing the martensitic phase transformation stress.

[0119] Because of the slow cooling rate, the holding time of the low-temperature, low-speed hot oil needs to be extended to 35s, but the residual stress is still higher than that of Comparative Example 1, indicating that the temperature of the hot oil has a greater impact on the uniformity of phase change than the flow rate.

[0120] Comparative Example Plasma processing time Grease heating conditions Coating thickness Waterproof rating Grease leakage rate Comparative Example 1 30s + 8s reprocessing 600 Pa·s → 35℃ 15nm IP68 ≤0.01% Comparative Example 2 25s+5s reprocessing 450 Pa·s (unheated) 10nm IP67 ≤0.03% Comparative Example 3 35s + 10s reprocessing 700 Pa·s → 35℃ 20nm IP68+ ≤0.005%

[0121] analyze:

[0122] Effect of plasma treatment time:

[0123] A 30-second treatment time can reduce the contact angle of the seal from 60° to 32° and increase the peel strength by 40%. After an additional 8 seconds of treatment, the surface active group density is uniform and the leakage rate is controlled at 0.01%.

[0124] While over-processing improves surface roughness, it may cause micro-cracks at the sealing lip, requiring power optimization to avoid damage.

[0125] The effect of coating thickness:

[0126] The 15nm fluorocarbon coating showed no leakage in the IP68 test, and the coefficient of friction was reduced to 0.08.

[0127] The 20nm coating has a denser film layer, which improves the waterproof rating to IP68+, but may increase the starting torque of the bearing, so a trade-off needs to be made in highly corrosive environments.

[0128] Comparative Example Matching gap grease injection precision Cap deformation control Lubrication life Comparative Example 1 0.018mm ±0.003g 80% deformation at the constant speed to constant force switching point 8000h Comparative Example 2 0.015mm ±0.005g Constant speed capping (constant force switching conditions not met) 7000h Comparative Example 3 0.020mm ±0.002g Displacement compensation during constant force capping is ±0.001mm. 8500h

[0129] analyze:

[0130] The contradiction of the fit-in clearance:

[0131] Although the clearance of Comparative Example 2 is smaller at 0.015mm, the roundness error of the raceway is higher than that of Comparative Example 1 due to the slightly larger deformation caused by heat treatment. The actual rotational accuracy is actually worse than that of the latter.

[0132] Comparative Example 3, by optimizing heat treatment parameters, still achieved a roundness of 0.0015 mm with a clearance of 0.020 mm, proving that multi-physics field synergistic control can break through the traditional understanding that "the smaller the clearance, the higher the precision".

[0133] Synergistic effect of grease injection and capping:

[0134] The triple compensation grease injection in Comparative Example 3 achieves an accuracy of ±0.002g. Combined with micro-displacement compensation during gland pressing, it improves the uniformity of grease distribution by 15% and extends the service life to 8500h.

[0135] In Comparative Example 2, the high-viscosity grease was not heated, resulting in an injection deviation of ±0.005g, which led to insufficient lubrication in some areas and shortened the service life to 7000h.

[0136] In summary, Comparative Example 1 achieves a balance between accuracy, efficiency, and cost, and is recommended as the standard process solution.

[0137] Comparative Example 2 reduces costs by shortening the heat preservation time and simplifying the grease injection heating process, while sacrificing 5% accuracy, making it suitable for mass production of automotive bearings.

[0138] Comparative Example 3 achieved an overall improvement in performance indicators by extending the heat treatment time and optimizing the coating thickness. Although this increased the cost, it is suitable for extreme working conditions such as deep sea and aerospace.

[0139] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A bearing precision manufacturing process based on multi-physical field synergistic regulation, characterized in that, The specific steps include: S1, cutting two sizes of forgings to obtain bearing inner and outer rings, respectively, and performing zoned gradient heating and staged cooling on the bearing inner and outer rings, 3D scanning the bearing inner and outer rings, dividing the raceway area, end face area and chamfer area, and configuring different frequency induction coils in the raceway area, end face area and chamfer area, respectively, using electromagnetic field coupling effect, realizing dynamic heat distribution through coil phase difference, and real-time monitoring of zoned temperature through an infrared thermal imaging system, when the temperature deviation is ≥5℃, dynamically reducing the coil power; S2, independently processing the cooled bearing inner and outer rings, and then fitting the bearing inner and outer rings, and collecting size data in real time and automatically calculating the matching allowance during processing by using a laser diameter measuring instrument; S3, pretreating the sealing element to improve the surface properties of the sealing element, and ensuring the stability of the performance of the lubricating grease through rheological regulation, before quantitative grease injection, using an online rotary rheometer to detect the viscosity and yield stress of the lubricating grease, when the viscosity of the lubricating grease is >500Pa·s, starting the electromagnetic induction heater to adjust the temperature of the lubricating grease to 35℃, and then performing quantitative grease injection, vacuumizing before grease injection, pre-pressing the sealing ring during grease injection, and releasing the vacuum after grease injection, and adopting a triple compensation mechanism of loss-in-weight metering, rheological compensation and environmental compensation during quantitative grease injection; S4, real-time capturing the deformation amount and deformation rate of the sealing lip edge through a high-speed machine vision system, constructing a two-dimensional deformation cloud chart according to the captured data, and intuitively displaying the deformation distribution to complete the gland work of the sealing element: When the deformation amount of the sealing lip edge is <80% of the target value, constant speed gland pressing is adopted; When the deformation amount of the sealing lip edge is ≥80% of the target value, constant force gland pressing is switched, and displacement adaptive compensation is adopted.

2. The bearing precision manufacturing process based on multi-physical field collaborative regulation according to claim 1, characterized in that: When heating the bearing inner and outer rings, gradient heating is adopted, and the heating range is 80-850℃, wherein a heat preservation node is set every 10℃ of heating, and the heat preservation time is 3-8min; When staged cooling the bearing inner and outer rings, hot oil is first passed to delay cooling, wherein the hot oil temperature is 130-170℃, the flow rate is 2-4m / s, and the hot oil is maintained for 20-35s to reduce the temperature gradient of the bearing inner and outer rings in the initial cooling stage by using the buffering characteristics of the hot oil; and 18m / s high-speed air cooling is then switched to complete phase change, and rapid cooling promotes the transformation of the structure of the bearing inner and outer rings into the required martensite structure.

3. The bearing precision manufacturing process based on multi-physical field collaborative regulation according to claim 1, characterized in that, In the S2, the processing procedures of the bearing inner ring include end face grinding, outer circle grinding, superfinishing outer circle, inner groove grinding, inner circle grinding and outer groove superfinishing; The processing procedures of the bearing outer ring include end face grinding, outer circle grinding, outer groove grinding and outer groove superfinishing.

4. The bearing precision manufacturing process based on multi-physical field synergistic regulation of claim 1, wherein, In the S2, the double-station fitting machine automatically adjusts the fixture spacing according to the calculation result of the clearance value, marks a unique pairing number after pairing, and the clearance precision of the fitted bearing inner and outer rings is ≤0.005mm.

5. The bearing precision manufacturing process based on multi-physical field synergistic regulation of claim 1, wherein, In the S3, when the seal is pretreated, the atmospheric low-temperature plasma processor is used to perform 25-35 s scanning treatment on the seal to introduce -OH / -COOH groups. When the contact angle detector is used for real-time detection, if the seal does not meet the standard, it is supplemented for 5-10 s.

6. The bearing precision manufacturing process based on multi-physical field synergistic regulation of claim 1, wherein, In the S3, the elastic sealing ring and the vacuum suction pipeline are arranged on the grease injection nozzle of the grease injection machine.

7. The bearing precision manufacturing process based on multi-physical field synergistic regulation of claim 1, wherein, Further comprising: S5, after the completion of the grease injection and the cover pressing, the bearing is placed in an ultrasonic cleaning tank, and deionized water filtered by ultrafiltration is used as a cleaning medium to remove the trace grease residue and the tiny particles on the surface of the bearing; S6, after the cleaning, the bearing is subjected to drying treatment, and a carbon fluoride (CFx) coating is deposited on the surface of the bearing.

8. The bearing precision manufacturing process based on multi-physical field synergistic regulation of claim 7, wherein, In the S6, the thickness of the carbon fluoride CFx coating is 10-20 nanometers.

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