Vacuum grease injection method for double-row hub bearing unit

Abstract

The present application belongs to the technical field of precision machinery assembly and lubrication, and specifically discloses a vacuum grease injection method for double-row hub bearing units, introduces temperature correction coefficient, grease viscosity correction coefficient and bearing structure coefficient, optimizes the calibration and calculation logic of the system volume compression coefficient, and improves the multi-dimensional correction model of the grease supplement amount; through the closed-loop control system of pressure-flow real-time feedback, intelligent identification of the double-row raceway grease injection stage, adaptive switching of the grease injection rate, and accurate detection and quantitative grease supplement of the backflow air are realized, so that the bearing internal cavity is completely, densely and bubble-free filled with lubricating grease, the lubrication reliability and long-term operation life of the hub bearing unit are greatly improved, the intelligent process system integrating monitoring, identification, control and compensation is constructed, the dependence on the experience of the operating personnel is reduced, and the process stability and replicability are improved.

Description

Technical Field

[0001] This invention belongs to the field of precision mechanical assembly and lubrication technology, specifically relating to a vacuum grease injection method for a double-row wheel hub bearing unit. Background Technology

[0002] Wheel bearing units are core components of automotive chassis systems, responsible for load transmission and rotation guidance. With the automotive industry's increasing demands for safety, reliability, and modular assembly, wheel bearings have evolved from first- and second-generation separate structures to the widely used, highly integrated third-generation wheel bearing units. These units typically integrate double-row angular contact ball bearings or double-row tapered roller bearings with flanges and wheel hubs. Some wheel bearing units also integrate anti-lock braking system (ABS) sensors or signal loops during manufacturing, achieving overall performance optimization and simplified assembly. This has become the mainstream application for the wheels of modern passenger cars and light commercial vehicles.

[0003] The manufacturing process of wheel hub bearing units typically includes two stages: the first stage is the precision machining of each metal component, and the second stage is the assembly process. During the assembly stage, the following steps are performed sequentially: component cleaning, dimensional selection and fitting, grease filling, sealing component press-fitting, and performance testing. Grease filling, usually completed before sealing component press-fitting, is a critical process in the wheel hub bearing unit assembly. This step directly affects the lubrication state of the rolling elements and raceways inside the bearing. It not only needs to achieve sufficient and uniform distribution within complex cavities such as double-row raceways, but also needs to meet strict quantitative control requirements and minimize air entrainment to avoid abnormal noises or premature bearing failure during operation.

[0004] In a double-row hub bearing unit, two rows of rolling elements are spaced apart axially and are each constrained by a cage. Although the cage itself does not constitute a sealing structure, its window shape, rib distribution, and the narrow gaps formed with the inner and outer rings cause the flow path of the grease inside the bearing to exhibit a significant non-linear characteristic. During the injection process, the grease needs to pass sequentially through the cage window, the rolling element gaps, and the limited connecting space between the two raceways. The flow cross-section changes continuously in different areas, resulting in a significant increase in local flow resistance. These structural characteristics cause differences in the grease velocity distribution and filling sequence inside the bearing, which can easily lead to uneven grease distribution between the two raceways and different areas inside the bearing. In existing processes, the grease injection process often relies on preset grease volume or grease injection terminal pressure as control and judgment criteria. These parameters can only reflect the overall grease injection status and are difficult to accurately characterize the actual distribution of grease between the two raceways, making it difficult to determine whether the double raceways have been synchronously and adequately greased.

[0005] Meanwhile, there is an unavoidable time window between the completion of grease injection and the release of vacuum, and the press-fitting of the sealing components. During this stage, the bearing interior transitions from a negative pressure state to a normal pressure environment, making it prone to air backflow into the bearing. Since existing grease injection processes typically lack real-time identification and control methods for the bearing's internal state during this stage, air backflow can easily disrupt the already distributed grease, leading to inconsistent lubrication conditions in the double-row raceways, and even creating potential air trapping hazards in localized areas, affecting the bearing's operational reliability and consistency. Summary of the Invention

[0006] Based on the above background, the purpose of this invention is to overcome the shortcomings of the existing technology in the vacuum grease injection process of double-row wheel hub bearing units, which is rough and lacks process feedback. In particular, the grease injection is incomplete due to air backflow before the grease injection and sealing of the two raceways, which affects the long-term lubrication performance of the bearing. The invention provides an intelligent vacuum grease injection process and system based on real-time pressure-flow feedback, which can intelligently identify the grease injection stage, accurately control the grease injection process, and actively detect and compensate for backflow air. This achieves dense and bubble-free filling of the internal cavity of the bearing, thereby improving the grease injection quality and reliability.

[0007] This invention proposes a vacuum grease injection method for a double-row wheel hub bearing unit, the method comprising the following steps: Step 1: Configure the status of components related to grease injection; Specifically, this includes placing the double-row wheel hub bearing unit into the vacuum chamber, sealing and connecting the grease injection channel and the connecting pipe, initially closing the air inlet valve, grease replenishment valve, grease outlet valve and vacuum valve two of the grease pressure tank, and opening vacuum valve one to connect the vacuum chamber to the vacuum pump. Step two: Start the vacuum pump to evacuate the vacuum chamber; when the first preset condition is met, proceed to the next step. Specifically, the first preset condition is when the pressure sensor detects that the air pressure Pc in the vacuum chamber is less than or equal to the preset vacuum threshold Pc-set.

[0008] Step 3: Open vacuum valve 2 to evacuate the grease tank. When the second preset condition is met, close vacuum valve 2 and vacuum pump to complete the overall system evacuation. Specifically, the second preset condition is: when pressure sensor 2 detects that the pressure in the grease canister is Pg ≤ Pc-set.

[0009] Step 4: Open the air intake valve and stabilize the pressure of the grease tank at Pg-set1 through the pressure reducing valve 2. Open the grease outlet valve to perform high-speed grease filling on the first row of rollers and control the flow rate to be close to Qset1, where Pg-set1>Pc-set. Step 5: Real-time acquisition of Pc and instantaneous grease injection flow rate Q. When the third preset condition is met, it is determined that the first row of rollers is about to be filled. The pressure Pg in the grease can is controlled to Pg-set2, and the low-speed grease injection stage is entered, where Pg-set1>Pg-set2>Pc-set. At this time, the flow rate is close to Qset2, and Qset1>Qset2. Specifically, the third presupposition condition is: ≥ and ≤ hour, and This is the preset rate threshold.

[0010] Step 6: During the low-speed grease injection process, when the fourth preset condition is met, it is determined that the double-row raceway grease filling is complete, the air inlet valve and the grease outlet valve are closed, and the main grease injection ends. Specifically, the fourth presupposition condition is: ≥ and ≤ hour, and This is the preset rate threshold.

[0011] Step 7: Release the vacuum and monitor the pressure in real time. and traffic If at the same time, if the following is detected: ; ; If the grease injection effect detection module determines that there is backflow air inside the bearing, proceed to step eight; otherwise, proceed directly to the subsequent sealing component pressing process. This is the abnormal pressure rebound amount. This represents the rebound amount of abnormal traffic.

[0012] Step 8: Calculate the equivalent volume of the intruding air based on the improved calculation formula. and precise fat supplementation Control the fat replenishment tank to perform short-stroke fat replenishment; in, , , These are the system volume compressibility coefficient and temperature correction coefficient, respectively; the improved fat replenishment amount is... , The basic safety factor is used to compensate for system response errors and volume control errors during the fat replenishment process. It is determined based on historical process data, and its preferred value range is 0.02 to 0.10. This is the bearing process compensation coefficient, used to correct deviations caused by the structural and process design of different bearings during the grease filling process.

[0013] Compared with the prior art, the technical solution proposed in this invention brings the following significant beneficial effects: 1. This invention achieves intelligent identification of the filling state of the double-row raceways and adaptive and precise switching of the grease injection rate, significantly improving the quality and consistency of the grease injection process. By collecting and analyzing the dynamic changes in vacuum chamber pressure and grease flow rate in real time, this invention can accurately identify the key node where the grease is about to fill the first raceway and transition to the second raceway. After identifying the node, the system can automatically switch the grease injection rate. This adaptive rate control based on real-time feedback avoids problems such as grease turbulence, impact splashing, or air bubbles caused by sudden changes in flow cross-section or excessive flow velocity. It ensures that the two raceways can be filled with grease smoothly, sequentially, and fully, guaranteeing the uniformity and consistency of the lubrication state of the double-row raceways from the source of the process.

[0014] 2. An active detection and intelligent compensation mechanism for backflow air before sealing after grease injection was established, effectively solving the defect of incomplete grease injection caused by air backflow and improving the final lubrication reliability. After the main grease injection is completed, the invention continues to monitor the system status using pressure and flow sensors. When abnormal pressure rebound is detected and accompanied by a sudden change in flow, the amount of abnormal pressure rebound caused by air backflow is determined. Combined with the pre-calibrated system volume compression coefficient, the equivalent volume of the intruding air is dynamically calculated, and the precise amount of grease replenishment is determined accordingly. Subsequently, the grease injection and replenishment control module performs a short-stroke, quantitative grease replenishment to fill the gaps caused by backflow air. This precise compensation based on dynamic feedback completely eliminates the phenomenon of insufficient grease filling caused by air backflow inside the bearing, ensuring that the internal cavity of the bearing is completely and densely filled with grease before sealing, eliminating the risk of air trapping, and thus significantly improving the long-term operational reliability and lifespan of the bearing.

[0015] 3. An intelligent closed-loop process system integrating monitoring, identification, control, and compensation has been constructed. This invention organically integrates multiple links such as vacuum control, grease injection process monitoring, stage identification, rate switching, defect detection, and quantitative compensation through an intelligent control system, forming a complete process closed loop. The entire process makes dynamic decisions and adjustments based on real-time feedback of pressure and flow signals, exhibiting a high degree of adaptability and intelligence, significantly reducing reliance on operator experience, and improving process stability and replicability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the vacuum grease injection system for the wheel hub bearing unit with pressure-flow feedback according to the present invention; Figure 2 This is a block diagram of the control system for the vacuum grease injection system proposed in this invention; Figure 3 This is a flowchart of the vacuum grease injection method proposed in this invention; Figure 4 This is a schematic diagram illustrating the structural principle of the fat replenishment tank of the present invention. Detailed Implementation

[0018] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0019] This invention provides a vacuum grease injection method for a double-row wheel hub bearing unit. By constructing a closed-loop control system integrating vacuum control, grease injection process monitoring, and intelligent feedback adjustment, it achieves precise control of the sequential grease injection process of the double-row raceways and detection and compensation for potential backflow air in the cavity after grease injection. Its core lies in utilizing the real-time change characteristics of pressure and flow signals to automatically identify the transition points of the grease injection stage and execute differentiated control strategies, ultimately ensuring that the lubrication cavity inside the bearing is completely and densely filled with grease before sealing, without any air mixing in.

[0020] Figure 1 This is a schematic diagram of a vacuum grease injection system for a wheel hub bearing unit with pressure-flow feedback. The vacuum grease injection system includes: Vacuum chamber 2 is used to house the hub bearing unit 1 body. Vacuum valve 8 and gas filling valve 17 are installed on vacuum chamber 2. The other end of vacuum valve 8 is connected to vacuum pump 10 through connecting pipe 4. The other end of gas filling valve 17 is connected to gas tank 13 through connecting pipe. A pressure reducing valve 18 is installed on connecting pipe 4. Gas tank 13 is filled with inert gas. The grease canister 7 contains lubricating grease. The top of the grease canister 7 has an air inlet valve 5 and a vacuum valve 9. The air inlet valve 5 is connected to the gas tank 13 via a connecting pipe 4, on which a pressure reducing valve 16 is installed. The other end of the vacuum valve 9 is connected to a vacuum pump 10 via the connecting pipe 4. The grease canister 7 contains lubricating grease, and the bottom of the grease canister 7 has a grease outlet valve. The grease outlet valve 15 is connected to the connecting pipe 4, which passes through the wall of the vacuum chamber 2 and is sealed to the grease injection channel 3 of the wheel hub bearing unit 1. A flow sensor 14 is installed on the connecting pipe 4.

[0021] A grease filling tank 19 is fixed to the inner wall of the vacuum chamber 2; a grease filling valve 6 is located below the grease filling tank 19, and the grease filling valve 5 is connected to a connecting pipe 4, the other end of which is connected to a pipe connected to the grease injection channel 3.

[0022] As a further improvement to this application, a pressure-flow feedback intelligent vacuum grease injection system for the hub bearing unit is installed outside the vacuum chamber, the schematic diagram of which is shown below. Figure 2 As shown. The intelligent control system includes a vacuum control module, a grease injection / replenishment control module, and a grease injection effect detection module. The vacuum control module mainly controls the pressure changes and stabilization of the vacuum chamber and grease canister, and is electrically connected to the grease injection / replenishment control module, pressure sensor one, pressure sensor two, vacuum pump, vacuum valve one, vacuum valve two, pressure reducing valve one, pressure reducing valve two, inlet valve, grease outlet valve, and grease replenishment valve. The grease injection / replenishment control module mainly controls the filling and injection of lubricating grease and short-stroke grease replenishment, and is electrically connected to the vacuum control module, grease injection effect detection module, gas canister assembly, grease replenishment canister assembly, pressure reducing valve two, inlet valve, grease outlet valve, and grease replenishment valve. The grease injection effect detection module mainly identifies the filling status of the two raceways and determines whether grease replenishment is needed during grease injection of double-row wheel hub bearings, and is electrically connected to the grease injection / replenishment control module, pressure sensor one, flow sensor, and timer.

[0023] In this invention, the first row of raceways refers to the raceways that are preferentially connected to the grease injection channel and are filled with grease first during the grease injection process, and the second row of raceways refers to the raceways that are subsequently filled with grease during the grease injection process, relative to the first row of raceways.

[0024] For wheel bearing units with dedicated grease injection channels, the conventional process involves injecting grease through these channels, followed by press-fitting the sealing assembly and finally sealing the grease injection port. For wheel bearing units without dedicated grease injection channels, grease injection is typically performed before press-fitting the sealing assembly, or in a pre-press-fit state where the sealing assembly is not fully closed, with final sealing completed after grease injection. Regardless of the specific process path, during the process window from grease injection to final sealing, the complex cavities and narrow gaps inside the double-row wheel bearing unit are connected to the external environment, allowing for potential gas exchange.

[0025] The vacuum grease injection process and compensation method based on pressure-flow feedback for double-row wheel hub bearing units involved in this invention focuses on the monitoring and control of the grease injection process and the state of the cavity before sealing. This is not necessarily dependent on the specific structural feature of whether the wheel hub bearing unit has a dedicated grease injection channel. To clearly describe the control logic and fluid path of the grease injection process, this specification will subsequently use a typical structure with a grease injection channel as an example, but this should not be construed as limiting the scope of application of this invention.

[0026] For wheel bearing units with a dedicated grease injection channel, grease is typically injected through the channel before the sealing assembly is press-fitted and the grease injection channel is sealed. For wheel bearing units without a dedicated grease injection channel, grease injection is usually completed before pressing the sealing assembly, or grease is injected before the sealing assembly is fully closed, followed by complete sealing. Therefore, before grease injection and sealing, the narrow internal cavity of the double-row wheel bearing unit is connected to the outside of the main body of the wheel bearing unit. Whether or not there is a dedicated grease injection channel does not affect the main content of this invention. For the convenience of describing the grease injection process, a wheel bearing unit with a grease injection channel is used as an example.

[0027] The method for grease injection into the raceway area of ​​a double-row wheel hub unit is as follows: Figure 3 As shown, the specific steps include: Step 1: Configure the status of components related to grease injection; Specifically, the double-row wheel hub bearing unit 1 is placed in the vacuum chamber 2, the grease injection channel 3 is sealed and connected to the connecting pipe 4, the air inlet valve 5, the grease replenishment valve 6, the grease outlet valve 15 and the vacuum valve 9 of the pressure grease tank 7 are initially closed, and the vacuum valve 8 is opened to connect the vacuum chamber 2 with the vacuum pump 10. Through the above operations, the air pressure Pc inside the vacuum chamber 2 and the air pressure Pg inside the pressure vessel 7 are both at the external atmospheric pressure.

[0028] Step 2: Start vacuum pump 10 to evacuate vacuum chamber 2. When the first preset condition is met, proceed to the next step. Specifically, the body of the double-row wheel hub bearing unit 1 is located inside the vacuum chamber 2, and its internal lubrication chamber is connected to the chamber through structural gaps and is evacuated simultaneously. When the first preset condition is met, i.e., the pressure sensor 11 detects that Pc ≤ Pc-set, the air pressure Pc inside the vacuum chamber 2 is similar to the air pressure of the lubrication chamber inside the bearing, which is lower than the external atmospheric pressure.

[0029] Step 3: Open vacuum valve 29 to evacuate grease tank 7. When the second preset condition is met, close vacuum valve 29 and vacuum pump 10 to complete the overall system evacuation. Specifically, the second preset condition is that the pressure sensor 12 detects that the pressure in the grease canister is Pg ≤ Pc-set.

[0030] Step 4: Open the intake valve 5, stabilize the pressure of the grease tank 7 at Pg-set1 through the pressure reducing valve 2 16, open the grease outlet valve to perform high-speed grease filling of the first row of rollers, and control the flow rate to be close to Qset1, where Pg-set1>Pc-set; Specifically, this step is used to fill the first row of raceways with grease. At this time, vacuum pump 10 and vacuum valve 2 9 are both closed. The air inlet valve 5 is opened, so that the inert gas in the gas tank 13 enters the space above the grease tank 7 at a set stable pressure after being regulated by pressure reducing valve 2 16. By adjusting pressure reducing valve 2 16, the pressure in the grease tank 7 is controlled at a preset stable value Pg-set1 that is slightly higher than the pressure Pc-set in the vacuum chamber, so as to provide a stable and controllable pressure difference. At this time, the pressure Pg in the grease tank 7 is stably controlled at Pg-set1, and Pg-set1>Pc-set is satisfied, and the flow rate Q is controlled to be close to Qset1. Grease outlet valve 15 is opened. Driven by the stable pressure difference, the grease enters the bearing from the grease tank 7 through the grease injection channel. The setting of pressure reducing valve 2 16 ensures the stability of the grease injection power source (gas pressure in the grease tank) and avoids unstable grease injection flow due to gas tank pressure fluctuations, providing a stable prerequisite for subsequent accurate stage identification based on flow and pressure signals.

[0031] Step 5: Real-time acquisition of Pc and instantaneous grease injection flow rate Q. When the third preset condition is met, it is determined that the first row of rollers is about to be filled. The pressure Pg in the grease can is controlled to Pg-set2, and the low-speed grease injection stage is entered, where Pg-set1>Pg-set2>Pc-set. At this time, the flow rate is close to Qset2, and Qset1>Qset2. Specifically, the third presupposition condition is: ≥ and ≤ hour, and For the preset rate threshold, This step involves identifying the grease filling status of the first raceway and controlling deceleration. During the grease filling process, the flow sensor 14 collects the instantaneous flow rate value Q in real time, and the timer records the time data t. When the grease is almost full of the first raceway, the effective flow cross-sectional area inside the bearing decreases, and the equivalent flow resistance of the system increases, which manifests as... ≥ , ≤ When both rate threshold conditions are met, the grease injection effect detection module determines that the grease filling index of the first row of raceways has been completed based on the characteristics of increased pressure rise slope and flow rate decay. Subsequently, the grease injection and replenishment control module reduces the inert gas intake rate by controlling the pressure reducing valve 16, and at this time, the low-speed grease injection stage is entered.

[0032] Step 6: During the low-speed grease injection process, when the fourth preset condition is met, it is determined that the double-row raceway grease filling is complete, the air inlet valve 5 and the grease outlet valve 15 are closed, and the main grease injection ends. Specifically, the fourth presupposition condition is: ≥ and |≤ hour, and This is the preset rate threshold.

[0033] This step involves filling and determining the completion of the second raceway with grease. Continue grease injection at a low speed. As the second raceway is gradually filled, the pressure and flow rate stabilize again, as shown in the following diagram. ≥ , ≤ The grease injection effect detection module determined that both rows of raceways inside the bearing had been filled with grease.

[0034] Step 7: Release the vacuum and monitor the pressure in real time. and traffic If at the same time, if the following is detected: ; ; If the grease injection effect detection module determines that there is backflow air inside the bearing, proceed to step eight; otherwise, proceed directly to the subsequent sealing component pressing process. This is the abnormal pressure rebound amount. This represents the rebound amount of abnormal traffic.

[0035] Step 8: Calculate the equivalent volume of the intruding air based on the improved calculation formula. and precise fat supplementation Control the fat replenishment tank to perform short-stroke fat replenishment; in, , , These are the system volume compressibility coefficient and temperature correction coefficient, respectively; the improved fat replenishment amount is... , The basic safety factor is used to compensate for system response errors and volume control errors during the fat replenishment process. It is determined based on historical process data, and its preferred value range is 0.02 to 0.10. This is the bearing process compensation coefficient, used to correct deviations caused by the structural and process design of different bearings during the grease filling process.

[0036] In one specific implementation, the system volume compression coefficient in step eight Through preliminary calibration, K remained stable under the same equipment, the same wheel hub model, and the same vacuum conditions. During the process development phase, after evacuating the empty vacuum chamber containing the wheel hub unit, different known micro-volumes were injected. The gas was recorded, and the pressure rise was recorded. ,right but .

[0037] Temperature correction factor The calculation formula is: ,in This refers to the absolute temperature inside the vacuum chamber during actual production. The absolute temperature inside the vacuum chamber when calibrating the system's volume compressibility coefficient.

[0038] As a further improvement to this application, the structural principle diagram of the fat replenishment tank 19 in step eight is as follows: Figure 4 As shown.

[0039] The grease filling tank 19 mainly includes a piston 25, a piston rod 24, and a drive module 23. The lower part of the tank is divided by the piston 25 into a grease chamber 26, which contains lubricating grease. One end of the piston rod 24 is connected to the piston 25, and the other end is connected to the output of the drive module 23. The drive module 23 can be pneumatically or electrically driven, and it receives instructions from the grease filling control module, driving the piston 25 to perform precise short-stroke advances according to the volume Vadd to be compensated. The drive module 23 can integrate a displacement sensor to provide real-time feedback on the displacement of the piston rod 24. This displacement data, combined with the cross-sectional area data of the grease chamber, allows for precise control of the piston 25's thrust stroke to control the grease replenishment volume, ensuring that the dispensed grease volume is precisely equal to Vadd. The grease tank 19 has a grease replenishment channel 20, one end of which connects to the bottom of the grease chamber 26, and the other end connects to the grease replenishment valve 6. The grease replenishment valve 6 is located outside the grease tank. During grease replenishment, the grease replenishment valve 6 opens, and the grease enters the grease replenishment channel 20 under the thrust of the piston 25. In addition, the top of the grease tank 19 is provided with a grease filling port 21, which is connected to the bottom of the grease chamber 26 through a grease filling channel 22. The grease filling port 21 and the grease filling channel 22 are used to replenish the grease tank from the outside after the grease in the grease chamber 26 is exhausted. This grease replenishment operation is usually carried out during non-grease injection production periods. When the grease is full, the piston 25 is located at the top of the grease chamber.

[0040] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0041] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0042] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0043] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0044] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A vacuum grease injection method for a double-row wheel hub bearing unit, characterized in that, The method includes the following steps: Step 1: Configure the status of components related to grease injection; Step 2: Start the vacuum pump (10) to evacuate the vacuum chamber (2). When the first preset condition is met, proceed to the next step. Step 3: Open vacuum valve 2 (9) to evacuate the grease tank (7). When the second preset condition is met, close vacuum valve 2 (9) and vacuum pump (10) to complete the overall evacuation of the system. Step 4: Open the air inlet valve (5), stabilize the pressure of the grease tank (7) at Pg-set1 through the pressure reducing valve 2 (16), open the grease outlet valve to perform high-speed grease filling on the first row of rollers, and control the flow rate to be close to Qset1, where Pg-set1>Pc-set, and Pc-set is the pressure in the vacuum chamber; Step 5: Real-time acquisition of Pc and instantaneous grease injection flow rate Q. When the third preset condition is met, it is determined that the first row of rollers is about to be filled. The pressure Pg in the pressure tank is controlled to Pg-set2, and the low-speed grease injection stage is entered. Step 6: During the low-speed grease injection process, when the fourth preset condition is met, it is determined that the double-row roller grease filling is completed, the air inlet valve (5) and the grease outlet valve (15) are closed, and the main grease injection ends.

2. The vacuum grease injection method according to claim 1, wherein the grease injection method further comprises: Step 7: Release the vacuum and monitor the pressure in real time. and traffic If at the same time, if the following is detected: ； ； If the grease injection effect detection module determines that there is backflow air inside the bearing, proceed to step eight; otherwise, proceed directly to the subsequent sealing component pressing process. This is the abnormal pressure rebound amount. This refers to the rebound amount of abnormal flow. Step 8: Calculate the equivalent volume of the intruding air based on the improved calculation formula. and precise fat supplementation Control the fat replenishment tank to perform short-stroke fat replenishment.

3. The vacuum grease injection method according to claim 1, wherein the first preset condition is: the pressure Pc detected by pressure sensor 1 (11) is ≤ Pc-set.

4. According to the vacuum grease injection method of claim 1, the second preset condition is: the pressure sensor (12) detects that the pressure of the grease injection tank Pg ≤ Pc-set.

5. The vacuum grease injection method according to claim 1, wherein the third preset condition is: ≥ and ≤ hour, and This is the preset rate threshold.

6. The vacuum grease injection method according to claim 1, wherein the fourth preset condition is: ≥ and ≤ hour, and This is the preset rate threshold.

7. The vacuum grease injection method according to claim 2, wherein the equivalent volume and precise fat supplementation The specific calculation method is as follows: , , These are the system volumetric compressibility coefficient and temperature correction coefficient, respectively; the improved fat replenishment amount is: , Based on the basic safety factor, This is the bearing process compensation coefficient.

8. The vacuum grease injection method according to claim 1, wherein step one specifically includes: Place the double-row wheel hub bearing unit (1) inside the vacuum chamber (2), seal the grease injection channel (3) and the connecting pipe (4), initially close the air inlet valve (5), grease replenishment valve (6), grease outlet valve (15) and vacuum valve two (9) of the grease canister (7), and open vacuum valve one (8) to connect the vacuum chamber (2) with the vacuum pump (10).

9. The vacuum grease injection method according to claim 7, wherein the temperature correction coefficient The calculation formula is: ,in This refers to the absolute temperature inside the vacuum chamber during actual production. The absolute temperature inside the vacuum chamber when calibrating the system's volume compressibility coefficient.

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