Device and method for measuring air gap of EPS booster

Abstract

The invention relates to equipment and a method for measuring an air gap of an EPS booster, and belongs to the technical field of automobile part precision detection equipment. The problems that the air gap between the lower rotor in the booster of the electric power steering system and the upper surface of the PHA is difficult to accurately and comprehensively measure, and parts are easy to wear and a sensor is easy to damage are solved. According to the scheme, equipment comprising five LVDT displacement sensors is adopted, three sensors measure three uniform distribution points on the upper surface of a lower rotor, two sensors measure two points on the upper surface of a PHA, and a data processing unit performs many-to-many difference calculation on three groups of lower rotor data and two groups of PHA data to obtain six groups of difference values and extract extreme values; the method comprises the steps of sensor zero clearing calibration, sample piece verification, product installation and data acquisition, specific difference value operation and extreme value qualified range judgment. The method is used for rapid and accurate automatic detection and quality judgment of key air gaps in the EPS booster production and assembly process.

Description

Technical Field

[0001] This invention belongs to the technical field of precision testing equipment for automotive parts, specifically relating to a device and method for measuring the air gap of an EPS booster. Background Technology

[0002] like Figure 1 As shown, in the production and assembly process of Electric Power Steering (EPS) boosters, the gap between the lower rotor and the Phaser A (PHA) is a critical dimensional control requirement introduced later. In the early design and production of EPS boosters, this gap was not a critical parameter that required mandatory testing; the assembly process mainly relied on the machining accuracy of the components and the assembly technology to ensure their fit. With the development of EPS systems towards higher precision and reliability, especially to improve system anti-interference capabilities, extend service life, and avoid abnormal wear and sensor failure, strict control requirements for this air gap have now been explicitly added to product quality standards. The accuracy of this gap directly affects the normal operating performance and long-term reliability of the EPS system. If this gap deviates from the design requirements, it may lead to abnormal contact and wear between the lower rotor and the PHA during operation. This wear not only damages the components themselves but may also further cause the sensor integrated on the PHA to fail, ultimately causing the entire EPS system to lose its power steering function.

[0003] Currently, measuring and controlling this gap on the production line presents certain challenges. Because this gap involves a three-dimensional assembly relationship, and the measurement references are located on two different parts, traditional single-point measurement methods cannot fully reflect the true condition of the entire mating surface, resulting in measurement blind spots or insufficient representativeness. Therefore, how to quickly and accurately obtain a gap value that truly reflects the entire circumferential fit and make reliable judgments about the product based on this is a practical problem faced in production line quality control. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0005] Another objective of this invention is to provide a device for measuring the air gap of an EPS booster, which can accurately obtain the extreme value of the air gap between the upper surface of the lower rotor and the upper surface of the PHA of the electric power steering system booster through multi-sensor collaborative measurement and data fusion processing, thereby effectively avoiding component wear and sensor failure caused by local dimensional deviations.

[0006] To achieve these objectives and other advantages of the present invention, an apparatus for measuring the air gap of an EPS booster is provided, comprising an apparatus frame, a housing support fixture, an upper pressure head, a zeroing calibration fixture, and a data processing unit. The housing support fixture is mounted on the equipment frame and is used to position and support the housing of the EPS booster; The upper pressure head is positioned above the housing support fixture, and the upper pressure head can reciprocate up and down relative to the housing support fixture; The zeroing calibration fixture is used to zero and calibrate five LVDT displacement sensors before measurement; The data processing unit is used to automatically calculate and output the maximum and minimum values ​​of the distance between the upper surface of the lower rotor and the upper surface of the PHA based on the data collected by the sensor. The data processing unit calculates the difference between the data from the three lower rotor measurement points and the data from the two PHA measurement points, performs many-to-many difference calculations, obtains six sets of difference values, and extracts the maximum and minimum values ​​from them as the final output.

[0007] The technical problem solved by this invention is to accurately measure the distance between the lower rotor and the upper surface of the power steering assembly (PHA) in an electric power steering system, avoiding abnormal contact and wear caused by dimensional deviations at this point, which could damage the sensors on the PHA and lead to EPS system failure. This is achieved by providing a dedicated measuring device that integrates multiple LVDT displacement sensors, a dedicated zeroing and calibration fixture, and a data processing unit. Five LVDT displacement sensors are arranged on the upper pressure head to accurately collect position data from three uniform points on the upper surface of the lower rotor and two points on the upper surface of the PHA. The data processing unit performs many-to-many difference calculations on these three and two sets of data, extracting the maximum and minimum values ​​from the six sets of differences as the final output. This achieves comprehensive and accurate quantitative measurement of critical assembly gaps, overcoming the limitations and inaccuracies of single-point measurement, providing a reliable data foundation for product quality assessment, and thus preventing wear and failure risks caused by improper gaps from the outset.

[0008] A method for detecting and judging the pass / fail status of air gap in EPS booster, the method is implemented using the aforementioned equipment, and includes the following steps: S1: Use a zeroing calibration fixture to zero and calibrate five LVDT displacement sensors, and then use upper gap sample, middle gap sample and lower gap sample respectively to verify the accuracy of the measuring equipment; S2: Install the electric power steering system booster onto the housing support fixture, start the equipment to press down the housing of the electric power steering system booster with the upper pressure head, and ensure that the five LVDT displacement sensors contact the three evenly distributed points on the upper surface of the lower rotor and the two relative position points on the upper surface of the PHA respectively. S3: Collect the measured data from five LVDT displacement sensors and record them as the values ​​of the first to fifth sensors respectively; S4: Subtract the value of the first sensor from the values ​​of the third sensor, the fourth sensor, and the fifth sensor respectively, and subtract the value of the second sensor from the values ​​of the third sensor, the fourth sensor, and the fifth sensor respectively, to obtain six sets of difference data; S5: Extract the maximum and minimum values ​​from the six sets of differences. If both are within the range of 4.161 mm to 4.933 mm, the product is deemed qualified.

[0009] The method of this invention includes verifying the accuracy of the measurement system using standard samples, precisely positioning and installing the product, collecting measured data from multiple sensors, performing specific data processing (i.e., subtracting the data from three lower rotor measurement points from the data from two PHA measurement points to obtain six sets of gap values), and finally determining whether the product is qualified based on whether the extreme values ​​(maximum and minimum values) of the gap fall within a preset qualified range (4.161 mm to 4.933 mm). This invention establishes an efficient, reliable, and standardized online inspection process that can automatically and objectively make rapid and accurate qualification judgments on the key assembly dimensions of each product, effectively ensuring the factory quality and consistency of the products and meeting the needs of large-scale production.

[0010] Preferably, in step S2, after the upper pressure head presses down on the housing of the electric power steering system booster, a stability judgment step is further included: The system monitors the output values ​​of five LVDT displacement sensors. If the fluctuation of the reading of each sensor is less than the set threshold within a preset time interval, the measurement state is determined to be stable, and step S3 is executed. If the reading of any sensor fluctuates beyond the set threshold within a preset time interval, the upper pressure head will rise, and the system will issue a prompt signal, indicating that the lower rotor and PHA surface should be cleaned again or the electric power steering system booster should be reinstalled and the measurement repeated.

[0011] In actual measurement processes, factors such as surface contamination of parts, minor installation instability, or transient interference to sensors can cause momentary distortion in measurement data, affecting the accuracy and repeatability of the final pass / fail judgment. This invention addresses this issue by introducing a stability judgment step before measurement data acquisition. This step continuously monitors the output fluctuations of all LVDT sensors and compares them with a preset stability threshold. Formal data acquisition only proceeds if all sensor readings remain stable within a specific time period; otherwise, the process is interrupted, prompting for cleaning or reinstallation. This invention significantly improves the measurement system's anti-interference capability and the repeatability of measurement results, ensuring that every acquired data accurately reflects the actual state of the product and avoiding misjudgments caused by transient interference.

[0012] Preferably, in the stability judgment step, if the reading fluctuation exceeds the set threshold, the system automatically identifies and displays the specific sensor number and its corresponding measurement surface area where the fluctuation exceeds the limit; at the same time, the device controls the pressure head to rise to a safe height and lock it. After the operator completes targeted cleaning or reinstallation according to the prompts and confirms that the fault is resolved, the system can be manually reset before the measurement process can be restarted.

[0013] When the system determines that the measurement status is unstable, operators struggle to quickly pinpoint the specific cause and location of the instability, potentially leading to blind or comprehensive cleaning and adjustments, which is inefficient and disrupts production. Further improvements based on stability assessment address this issue. When the system detects excessive fluctuations, it automatically and precisely locates which sensor(s) are malfunctioning and displays their corresponding measurement area. Simultaneously, the pressure head on the equipment automatically rises and locks, requiring the operator to perform targeted adjustments and obtain confirmation before manually resetting and resuming measurement. This significantly reduces troubleshooting time, guides operators in precise maintenance, avoids unnecessary operations, and ensures personnel and equipment safety during maintenance through hardware interlocking mechanisms, ultimately improving the overall efficiency and safety of the production line.

[0014] Preferably, in step S1, when verifying the accuracy of the measuring equipment using upper, middle, and lower gap samples, the system automatically records and stores the data from multiple verification measurements of each sample to form a long-term calibration history curve for the equipment. Before conducting formal product measurements, the system compares the current sample verification data with the historical calibration curve. If the current data deviates from the historical curve by more than the preset tolerance range, the system automatically prompts that the equipment needs to be maintained or recalibrated and suspends the product measurement process.

[0015] Relying solely on single or current-cycle calibration and verification is insufficient to effectively identify and warn of slow performance drift or potential accuracy degradation that may occur in measuring equipment over long-term use. This can lead to inaccurate measurement systems without the user's knowledge, potentially resulting in persistently incorrect product assessments. This invention addresses this by automatically recording and accumulating historical calibration data to create long-term calibration curves during the calibration and verification phase. Before each formal measurement, the current calibration data is compared with the historical curves to monitor the equipment's status. If a significant deviation is detected, an alert is issued, and maintenance is requested. This invention enables predictive maintenance and health monitoring of the measuring equipment, identifying problems before equipment accuracy significantly impacts product quality. It ensures long-term, stable measurement reliability from the source, avoiding quality risks caused by hidden equipment failures.

[0016] Preferably, when the system compares the current sample verification data with the historical calibration curve, it also establishes an independent historical performance sub-curve for the current verification data of each of the five LVDT displacement sensors and performs independent deviation analysis. When the system prompts that equipment maintenance or recalibration is required, it synchronously outputs and displays the independent deviation analysis results of each LVDT displacement sensor and identifies the specific sensor number suspected of performance degradation accordingly.

[0017] When the overall performance of a system's early warning equipment deviates and requires maintenance, maintenance personnel often struggle to quickly determine whether the problem lies with the entire system or with a specific sensor component. This leads to ineffective and untargeted maintenance, potentially requiring unnecessary comprehensive checks or calibrations. This invention refines the overall performance monitoring of the equipment down to the independent performance monitoring of each LVDT displacement sensor. By establishing and analyzing independent historical performance sub-curves for each sensor, it can simultaneously identify which sensor is suspected of performance degradation when the system issues an early warning. This invention narrows the maintenance focus from the entire system to the individual sensor, enabling more precise and efficient targeted maintenance, saving maintenance time and costs, and reducing the randomness of the maintenance process.

[0018] Preferably, after the system outputs and displays the independent deviation analysis results of each LVDT displacement sensor and identifies the specific sensor number suspected of performance degradation, the sensor suspected of performance degradation is independently recalibrated and verified using a zeroing calibration fixture. If the verification data of the sensor returns to normal after recalibration and matches the historical performance sub-curve, the abnormality mark of the sensor is cleared and it is allowed to continue to be used. If the data is still abnormal after recalibration, the system prompts that the specific sensor needs to be physically replaced or repaired. At the same time, the measurement process is automatically adjusted, and the data of the faulty sensor channel is temporarily blocked in subsequent product measurements, and the remaining valid sensor data is used for calculation and adjustment compensation.

[0019] When a system identifies a sensor suspected of performance degradation, it cannot effectively distinguish whether the sensor has suffered irreversible hardware damage or is merely experiencing temporary drift or accidental interference. Directly requiring replacement could lead to waste and downtime, while ignoring the issue could leave hidden problems. This invention adds an independent recalibration verification step for suspected sensors, using secondary diagnostics to differentiate the nature of the fault: if it's a temporary problem, data returning to normal after recalibration allows continued use; if it's a permanent fault, physical replacement is confirmed, and the system activates a degradation mode, disabling the faulty sensor and using data from remaining sensors for compensation calculations. This invention reduces unnecessary component replacements and maintenance downtime due to misjudgments, improving the scientific accuracy of maintenance decisions while ensuring the continuity of measurement functions, thus guaranteeing the continuous operation of the production line.

[0020] Preferably, the calculation and adjustment compensation using the remaining valid sensor data are performed according to the following steps: The system detects and confirms the channel number of the shielded faulty sensor, and identifies the original measurement object attribute of the faulty sensor. More specifically, it identifies that the sensor was originally used to measure the lower rotor surface or the PHA surface. Based on the layout of the remaining valid sensors and their measurement objects, the set of valid measurement points is reconstructed. If the failed sensor was originally used to measure the lower rotor surface, the data of the remaining two lower rotor measurement points are used, combined with their known theoretical 120-degree uniform distribution angle, and the height and inclination of the plane where it is located are fitted by the least squares method, and then the height value of the original third point's theoretical position is calculated. If the failed sensor was originally used to measure the PHA surface, only the data of the remaining one PHA measurement point is used, and it is directly used as the representative height value of the PHA surface. Substitute the calculated theoretical or representative values, along with the measured values ​​from the other effective sensors, into the original calculation process. The data processing unit continues to perform the original many-to-many differential calculation, subtracting the data from the three lower rotor measurement points from the data from the two PHA measurement points. The lower rotor measurement point data includes the actual measured value and the theoretical value obtained through calculation when necessary, while the PHA measurement point data includes the actual measured value and the representative value determined when necessary. This results in six sets of difference data, from which the maximum and minimum values ​​are extracted for qualification judgment.

[0021] When a faulty sensor is disabled, the original calculation logic cannot run directly due to the lack of data from that sensor, causing the pass / fail judgment process to be interrupted. This invention, for the aforementioned degraded measurement mode, specifically specifies detailed steps for using the remaining valid sensor data for calculation and adjustment compensation. Different data reconstruction strategies (such as plane fitting or single-point representation) are adopted according to different sensor types (measuring the lower rotor or PHA) to fill in the missing data points, thereby continuing to complete the original six sets of difference calculations and extreme value extraction. This invention enables the system to maintain basic measurement and judgment functions even when some sensors fail, greatly improving the fault tolerance and availability of the equipment, ensuring the continuity of the production process under abnormal conditions, and avoiding the risk of the entire production line being shut down due to a single sensor failure.

[0022] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0023] Figure 1 This is a diagram showing the installation structure of the lower rotor and phaser of the present invention; Figure 2This is a schematic diagram of the structure of one technical solution of the present invention.

[0024] 1. Lower rotor; 2. Phaser; 3. Equipment frame; 4. Upper pressure head; 5. Housing support fixture; Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0026] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0027] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials mentioned are commercially available. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0028] like Figure 2 As shown, the present invention provides a device for measuring the air gap of an EPS booster, including a device frame 3, a housing support fixture 5, an upper pressure head 4, a zeroing calibration fixture, and a data processing unit; The housing support fixture 5 is mounted on the equipment frame 3 and is used to position and support the housing of the EPS booster. The upper pressure head 4 is disposed above the housing support fixture 5, and the upper pressure head 4 can reciprocate up and down relative to the housing support fixture 5. The upper pressure head 4 includes five LVDT displacement sensors, three of which are used to measure the position data of three evenly distributed points on the upper surface of the lower rotor 1, and the other two LVDT displacement sensors are used to measure the position data of two points on the upper surface of the phaser 2PHA. The zeroing calibration fixture is used to zero and calibrate five LVDT displacement sensors before measurement; The data processing unit is used to automatically calculate and output the maximum and minimum values ​​of the distance between the upper surface of the lower rotor 1 and the upper surface of PHA based on the data collected by the sensor. The data processing unit performs many-to-many difference calculations by comparing the data from the three lower rotor 1 measurement points with the data from the two PHA measurement points to obtain six sets of differences, and then extracts the maximum and minimum values ​​as the final output.

[0029] The main frame of the measuring device is made of welded steel. The housing support fixture 5 is bolted to the center of the worktable of the equipment frame 3. Its profile can match the geometry of the lower part of the booster housing to achieve stable support. The upper pressure head 4 is mounted on the gantry beam of the equipment frame 3 via a linear guide pair and is driven by a servo motor to achieve precise lifting and lowering movements using a ball screw or cylinder. Five LVDT displacement sensors can be installed on the lower surface of the upper pressure head 4. Three sensors are distributed at 120-degree intervals on a circle with a theoretical diameter of approximately 80 mm to contact the upper surface of the lower rotor 1; the other two sensors can be arranged at a distance of approximately 60 mm to contact specific measurement points on the upper surface of the PHA. All sensor signal cables are collected via cable chains to the data processing unit in the control cabinet.

[0030] The zeroing calibration fixture can be a dimensionally stable simulation sample with a precisely known height difference between the simulated surfaces of the lower rotor 1 and the PHA. Before routine measurements, the operator places this fixture on the housing support fixture 5 and starts the equipment to execute the zeroing procedure. The equipment controls the upper pressure head 4 to descend to the measurement position. The data processing unit reads the voltage values ​​of the five sensors at this time and sets them as the zero-point references respectively. After calibration, the upper pressure head 4 is raised. This process ensures that each measurement starts with the same reference. The zero-point drift threshold can be set to 0.002 mm. If any sensor reading fluctuation exceeds this threshold during calibration, the system will prompt to check the sensor connection or clean the probe.

[0031] The data processing unit can employ an industrial-grade embedded computer, which acquires analog voltage signals from five LVDT sensors at a sampling frequency of 1000 times per second via a data acquisition card and converts them into digital quantities. During the measurement phase, after the upper pressure head 4, carrying the sensor, is pressed down to the product's measurement position and remains stable, the data processing unit acquires a set of steady-state data. The built-in algorithm program first verifies the validity of the data, and then performs calculations: the values ​​at the three lower rotor 1 measurement points (e.g., 4.599 mm, 4.572 mm, 4.570 mm) are subtracted from the values ​​at the two PHA measurement points (e.g., 0.040 mm, 0.052 mm), resulting in six sets of difference values. The program iterates through these six sets of results, quickly identifies the maximum and minimum values, displays them on the human-machine interface, and outputs the judgment result. Through multi-point, multi-dimensional data acquisition and comprehensive calculation, this device can effectively reflect the air gap distribution on the circumference of the assembly.

[0032] A method for detecting and judging the pass / fail status of air gap in EPS booster, the method is implemented using the aforementioned equipment, and includes the following steps: S1: Use a zeroing calibration fixture to zero and calibrate five LVDT displacement sensors, and then use upper gap sample, middle gap sample and lower gap sample respectively to verify the accuracy of the measuring equipment; S2: Install the electric power steering system booster onto the housing support fixture 5, start the equipment to make the upper pressure head 4 press down on the housing of the electric power steering system booster, and ensure that the five LVDT displacement sensors contact the three evenly distributed points on the upper surface of the lower rotor 1 and the two relative position points on the upper surface of the PHA respectively. S3: Collect the measured data from five LVDT displacement sensors and record them as the values ​​of the first to fifth sensors respectively; S4: Subtract the value of the first sensor from the values ​​of the third sensor, the fourth sensor, and the fifth sensor respectively, and subtract the value of the second sensor from the values ​​of the third sensor, the fourth sensor, and the fifth sensor respectively, to obtain six sets of difference data; S5: Extract the maximum and minimum values ​​from the six sets of differences. If both are within the range of 4.161 mm to 4.933 mm, the product is deemed qualified.

[0033] Existing methods for detecting air gaps in EPS boosters typically rely on manual, single-point measurements by operators using tools such as feeler gauges or dial indicators. This method is not only inefficient and difficult to meet production line cycle requirements, but the measurement results are also highly susceptible to human error and have poor repeatability. More importantly, manual measurements usually only obtain gap values ​​at a localized point, failing to comprehensively assess the gap uniformity across the entire circumferential mating surface, potentially leading to missed detections and making it difficult to reliably guarantee product quality.

[0034] This invention first uses a dedicated zeroing calibration fixture to perform zero-point calibration on the five LVDT displacement sensors integrated on the upper pressure head 4 to ensure a unified measurement reference. After calibration, standard gap samples of three different sizes (upper, middle, and lower) are used sequentially to verify the accuracy of the entire measurement system and confirm that the equipment is in good working order. After these preparations are completed, the operator places the EPS booster product to be tested on a dedicated housing support fixture 5. The fixture's surface design matches the lower part of the product housing, providing stable and reliable positioning. After starting the equipment, the upper pressure head 4 is smoothly pressed down under the drive of a servo motor, ultimately ensuring that the five LVDT sensor probes it carries make reliable contact with three points on the upper surface of the lower rotor 1 and two points on the upper surface of the PHA, respectively.

[0035] After the sensors maintain stable contact with the measuring surface, the system automatically collects real-time data from five sensors and records them as values ​​for the first to fifth sensors. The data processing unit then executes specific calculation logic: subtracting the values ​​of the first and second sensors, which reflect the height of the lower rotor 1, from the values ​​of the third, fourth, and fifth sensors, which reflect the height of the PHA, respectively. Through this pairwise difference calculation, six independent gap difference values ​​are obtained. After the calculation, the system automatically filters out the maximum and minimum values ​​from these six sets of differences. Finally, these two extreme values ​​are compared with a preset acceptable range (4.161 mm to 4.933 mm). Only when both the maximum and minimum values ​​fall within this range will the system determine that the product is qualified and allow it to proceed to the next process. This method, through automated measurement and multi-data-point fusion judgment, reduces human intervention and improves the ability to assess the overall gap condition of the product.

[0036] Furthermore, in step S2, after the upper pressure head 4 presses down on the housing of the electric power steering system booster, a stability judgment step is also included: The system monitors the output values ​​of five LVDT displacement sensors. If the fluctuation of the reading of each sensor is less than a set threshold within a preset time interval, the measurement state is determined to be stable, and step S3 is executed. If the reading of any sensor fluctuates beyond the set threshold within a preset time interval, the upper pressure head 4 will rise, and the system will issue a prompt signal, indicating that the lower rotor 1 and PHA surface should be cleaned again or the electric power steering system booster should be reinstalled and the measurement should be repeated.

[0037] In existing technologies, the measurement process for the air gap of EPS boosters typically lacks real-time assessment of the stability of the measurement state. Measurement is triggered immediately after the operator installs the product, and the system directly collects sensor readings and performs calculations. However, in actual production environments, contamination of the part's measurement surface, minor misalignments in workpiece installation, or transient electromagnetic interference can all cause fluctuations in the sensor output signal. Collecting data when it is unstable directly introduces measurement errors, affecting the accuracy and repeatability of the final pass / fail judgment. Often, multiple repeated measurements are required to obtain reliable results, reducing inspection efficiency.

[0038] This method introduces an automated stability assessment step before data acquisition. After the upper pressure head 4 is pressed down to the measurement position, the system does not immediately record data, but instead initiates a preset monitoring period, such as 500 milliseconds. During this period, the system continuously monitors the real-time output values ​​of five LVDT displacement sensors at a sampling frequency of 1000 times per second. An internal stability assessment threshold is set, for example, 0.001 mm. During the monitoring period, the system calculates the fluctuation range of each sensor reading in real time.

[0039] If the maximum fluctuation of the readings of all five sensors is less than 0.001 mm within the entire 500 milliseconds, the entire measurement system is considered to have reached a stable state, and the system automatically executes the subsequent data acquisition and calculation process. Conversely, if the fluctuation of the reading of any sensor exceeds the 0.001 mm threshold during this period, the current state is considered unstable. The system will immediately control the upper pressure head 4 to automatically lift away from the product surface, and at the same time, a prompt message will pop up on the human-machine interface, clearly instructing the operator to clean the measurement surfaces of the lower rotor 1 and PHA again, or to check and reinstall the booster product. The measurement process can only be restarted after the operator completes the corresponding operation and confirms it. This implementation method provides a prerequisite guarantee for obtaining true and reliable measurement results by adding a stability verification checkpoint before data acquisition.

[0040] Furthermore, in the stability judgment step, if the reading fluctuation exceeds the set threshold, the system automatically identifies and displays the specific sensor number and its corresponding measurement surface area where the fluctuation exceeds the limit; at the same time, the equipment controls the upper pressure head 4 to rise to a safe height and lock it. After the operator completes targeted cleaning or reinstallation according to the prompts and confirms that the fault is resolved, the system can be manually reset before the measurement process can be restarted.

[0041] In existing technologies, when a detection system determines that the measurement status is unstable, it can typically only issue a general alarm indicating an anomaly. When faced with an alarm, operators cannot quickly determine which sensor or its specific measurement location is causing the problem and often need to rely on experience to check all possible contact points one by one. This troubleshooting process is not only time-consuming and labor-intensive, severely impacting production rhythm, but also often occurs while the equipment remains operational, posing a safety hazard of accidental activation. Furthermore, it fails to effectively guide operators in performing precise maintenance.

[0042] The implementation of this method refines the response to unstable states. When the system detects a sensor reading fluctuation exceeding a threshold of 0.001 mm and determines it to be unstable, its response mechanism is not limited to alarms. The system immediately and automatically diagnoses which sensor channel(s) are experiencing abnormal readings and prominently displays the sensor number on the human-machine interface. More importantly, the interface simultaneously displays a pre-stored tooling diagram, clearly highlighting the actual measurement area corresponding to the sensor number, such as specifying "Lower Rotor 1B Zone" or "PHA Left Measuring Point," thus transforming the abstract channel number into a concrete spatial location.

[0043] Simultaneously, the equipment control system immediately triggers the safety interlock procedure. The upper pressure head 4 automatically rises to a preset safe height, and the equipment then enters a locked state, prohibiting the execution of any measurement commands. Based on the precise prompts on the interface, the operator can quickly locate the problem area for targeted cleaning or reinstallation and adjustment. Only after the operator confirms that the problem has been resolved and manually resets the device via the "Fault Resolution Confirmation" button on the interface will the locked state be released, allowing the next measurement cycle to proceed. This implementation method, combining precise positioning with hardware interlocks, transforms fault diagnosis from large-scale, blind operations to small-scale, precise work, reducing processing time and enhancing operational safety.

[0044] Furthermore, in step S1, when verifying the accuracy of the measuring equipment using upper, middle, and lower gap samples, the system automatically records and stores the data from multiple verification measurements of each sample, forming a long-term calibration history curve for the equipment. Before conducting formal product measurements, the system compares the current sample verification data with the historical calibration curve. If the current data deviates from the historical curve by more than the preset tolerance range, the system automatically prompts that the equipment needs to be maintained or recalibrated, and pauses the product measurement process.

[0045] In existing technologies, the verification of the accuracy of measuring equipment typically relies on single or periodic calibration of standard samples. Operators use samples for calibration, only momentarily comparing the current measurement result with the known nominal value of the sample; if the comparison passes, the equipment is considered normal. This method cannot detect the slow performance degradation that may occur over time, such as linear drift of sensors or minor wear of mechanical structures. Often, problems are only discovered after the equipment has developed significant measurement errors and affected product quality. At this point, maintenance is merely a remedial measure, and may have already led to the misjudgment of a batch of products.

[0046] The implementation of this method establishes a long-term monitoring mechanism for the equipment's performance. During each routine calibration verification using upper, middle, and lower gap samples, the system not only determines whether the data is acceptable but also automatically stores multiple verification measurement data (such as force and temperature readings) for each sample, along with timestamps, in a historical database. Over time, the system generates a long-term calibration history curve for the entire equipment, with time on the horizontal axis and measured values ​​on the vertical axis. This curve essentially reflects the drift trend of the equipment's overall performance.

[0047] Before conducting formal product measurements, the system automatically compares the latest data obtained from current sample verification with a calibration curve built upon historical data. The system has a preset tolerance range, such as 0.005 mm. If the deviation of the current verification data from the historical calibration curve exceeds this range, the system determines that the equipment may be at risk of accuracy degradation, automatically displays a prompt, and explicitly recommends that the equipment be maintained or recalibrated. It also pauses subsequent product measurement processes to prevent potential batch misjudgments. This approach transforms equipment accuracy control from passive, periodic maintenance to data-driven, proactive predictive maintenance.

[0048] Furthermore, when the system compares the current sample verification data with the historical calibration curve, it also establishes an independent historical performance sub-curve for the current verification data of each of the five LVDT displacement sensors and performs independent deviation analysis. When the system prompts that equipment maintenance or recalibration is required, it synchronously outputs and displays the independent deviation analysis results of each LVDT displacement sensor, and identifies the specific sensor number suspected of performance degradation accordingly.

[0049] While multi-sensor measurement systems are widely used in existing production line quality inspection systems, when the overall system performance shows a drift warning, it can usually only indicate that the equipment needs overall maintenance, without specifying which particular sensor is malfunctioning. Operators often need to rely on experience to check all sensors one by one, or directly perform a complete recalibration of the equipment. The entire process is time-consuming, labor-intensive, and lacks specificity, seriously affecting production efficiency and maintenance costs.

[0050] To address the aforementioned issues, this implementation introduces an independent performance monitoring mechanism for each LVDT displacement sensor. During standard sample verification, the system not only records overall measurement data but also establishes and updates an independent historical performance sub-curve for each of the five LVDT displacement sensors, continuously tracking the measurement value trends of each sensor over long-term use. When the system determines that device performance has drifted based on the overall calibration history curve and indicates the need for maintenance, it simultaneously outputs a detailed report showing the independent deviation of each sensor's current verification data from its own historical sub-curve. The report clearly identifies the specific sensor number whose deviation exceeds the allowable range, guiding maintenance personnel to quickly pinpoint the sensor suspected of performance degradation. Operators can then directly perform targeted checks, cleaning, or calibration on the specified sensors, eliminating the need for indiscriminate processing of the entire system, significantly improving maintenance efficiency and accuracy, and reducing unnecessary maintenance time and resource consumption.

[0051] Furthermore, after the system outputs and displays the independent deviation analysis results of each LVDT displacement sensor and identifies the specific sensor number suspected of performance degradation, the sensor suspected of performance degradation is independently recalibrated and verified using a zeroing calibration fixture. If the verification data of the sensor returns to normal after recalibration and matches the historical performance sub-curve, the abnormality mark of the sensor is cleared and it is allowed to continue to be used. If the data is still abnormal after recalibration, the system prompts that the specific sensor needs to be physically replaced or repaired. At the same time, the measurement process is automatically adjusted, and the data of the faulty sensor channel is temporarily blocked in subsequent product measurements, and the remaining valid sensor data is used for calculation and adjustment compensation.

[0052] In existing testing equipment maintenance procedures, when the system alerts to a potential sensor malfunction, there is often a lack of effective secondary diagnostic mechanisms to distinguish between temporary signal drift and permanent hardware damage. Maintenance personnel often face a dilemma: either directly replace the sensor, potentially leading to unnecessary spare parts consumption and downtime; or ignore the alarm and continue use, which could affect the accuracy of subsequent measurement results due to potential hardware failure, or even cause misjudgment of the product.

[0053] To address this challenge, this implementation adds a separate recalibration verification step. After identifying a specific sensor number suspected of performance degradation on the interface, the system does not immediately require physical replacement. Following the instructions, the operator places a dedicated zeroing calibration fixture on the equipment and initiates an independent recalibration program for that individual sensor. The system controls the pressure head 4 to descend, ensuring stable contact between the suspected sensor probe and the precision reference surface of the calibration fixture. The system then collects the sensor's output data under a known reference. This recalibration data is compared to the sensor's historical performance sub-curve. If the data returns to normal and matches the historical trend, the system determines that the sensor's drift is only temporary, automatically clears its anomaly marker, and the equipment can immediately resume normal operation. If the recalibration data remains significantly abnormal and shows an uncorrectable deviation from the reference value, the system ultimately confirms a hardware failure in the sensor and explicitly indicates the need for physical replacement or repair. Simultaneously, the system automatically adjusts subsequent product measurement procedures, temporarily disabling confirmed faulty sensor channels during calculations and enabling adjustment compensation algorithms based on remaining valid sensor data. This ensures measurement continuity while awaiting maintenance personnel to perform replacement operations. This implementation significantly improves the scientific rigor of maintenance decisions by introducing recalibration verification as a decision-making step, effectively avoiding unplanned downtime and resource waste caused by misjudgments.

[0054] Furthermore, the calculation and adjustment compensation using the remaining valid sensor data are performed as follows: The system detects and confirms the channel number of the shielded fault sensor, and identifies the original measurement object attribute of the fault sensor. More specifically, it identifies that the sensor was originally used to measure the surface of the lower rotor 1 or the PHA surface. Based on the layout of the remaining valid sensors and their measurement objects, the set of valid measurement points is reconstructed. If the failed sensor was originally used to measure the surface of the lower rotor 1, the data of the remaining two measurement points of the lower rotor 1 are used, combined with its known theoretical 120-degree uniform distribution angle, and the height and inclination of the plane where it is located are fitted by the least squares method, and then the height value of the original third point's theoretical position is calculated. If the failed sensor was originally used to measure the PHA surface, only the data of the remaining PHA measurement point is used, and it is directly used as the representative height value of the PHA surface. Substitute the calculated theoretical or representative values, along with the measured values ​​from the other effective sensors, into the original calculation process. The data processing unit continues to perform the original many-to-many difference calculation, subtracting the data from the three lower rotor 1 measurement points from the data from the two PHA measurement points. The lower rotor 1 measurement point data includes the actual measured value and the theoretical value obtained through calculation when necessary, while the PHA measurement point data includes the actual measured value and the representative value determined when necessary. This results in six sets of difference data, from which the maximum and minimum values ​​are extracted for qualification judgment.

[0055] Under current technological conditions, when a sensor in a measurement system is confirmed to be faulty, the entire measurement process is often forced to stop. Since the original algorithm relies on all data from five fixed measurement points, the absence of data from any one channel prevents the system from performing the intended many-to-many differential calculation, thus failing to output a valid gap extreme value for acceptance judgment. This often causes production line shutdowns until the faulty sensor is replaced and recalibrated, severely impacting production efficiency and overall equipment utilization.

[0056] To address this critical issue, this implementation introduces an intelligent data reconstruction and adjustment compensation mechanism. Once the system confirms a sensor channel malfunction and disables it, its built-in compensation algorithm immediately activates. The system first automatically identifies the disabled sensor, determining whether it was originally responsible for measuring the lower rotor 1 surface or the PHA surface. This determination forms the basis for subsequent data reconstruction strategies.

[0057] If the faulty sensor was originally used to measure the surface of the lower rotor 1, the system utilizes the real data collected by the remaining two normally functioning sensors on the lower rotor 1. Based on the known geometric layout where these three measuring points should be evenly distributed at 120 degrees, the system employs a least-squares fitting algorithm to deduce the spatial orientation of the entire lower rotor 1 measuring plane from the two real data points, thereby accurately calculating the height estimate of the theoretical location of the faulty sensor.

[0058] If the faulty sensor was originally used to measure the PHA surface, the situation is relatively simple. Since the upper surface of the PHA is usually considered as a whole reference plane, the system will directly use the single data measured by the remaining normal PHA sensor as the representative height value of the entire PHA surface.

[0059] Subsequently, the system substitutes these calculated theoretical or representative height values, along with the measured data from all other normal sensors, into the original core calculation process. The data processing unit continues to execute the predetermined calculation logic, subtracting the data from the three lower rotor 1 measuring points from the data from the two PHA measuring points one by one, thus still obtaining six complete sets of gap difference values, and extracting the maximum and minimum values ​​from them for the final qualification judgment.

[0060] The core value of this implementation lies in its use of redundant software algorithm design to compensate for temporary deficiencies in hardware sensors. This allows the equipment to maintain basic and reliable measurement functions even in degraded modes caused by individual sensor failures, greatly improving the continuous operation capability of the production line and the overall availability of the equipment.

[0061] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A device for measuring the air gap of an EPS booster, characterized in that, This includes the equipment frame, housing support fixture, upper pressure head, zeroing and calibration fixture, and data processing unit; The housing support fixture is mounted on the equipment frame and is used to position and support the housing of the EPS booster; The upper pressure head is positioned above the housing support fixture, and the upper pressure head can reciprocate up and down relative to the housing support fixture; The upper pressure head includes five LVDT displacement sensors, of which three LVDT displacement sensors are used to measure the position data of three evenly distributed points on the upper surface of the lower rotor, and the other two LVDT displacement sensors are used to measure the position data of two points on the upper surface of the PHA. The zeroing calibration fixture is used to zero and calibrate five LVDT displacement sensors before measurement; The data processing unit is used to automatically calculate and output the maximum and minimum values ​​of the distance between the upper surface of the lower rotor and the upper surface of the PHA based on the data collected by the sensor. The data processing unit performs many-to-many difference calculations between the data from the three lower rotor measurement points and the data from the two PHA measurement points to obtain six sets of differences, and extracts the maximum and minimum values ​​from them as the final output.

2. A method for detecting and judging the quality of air gaps in EPS boosters, characterized in that, This method is implemented using the device described in claim 1, and includes the following steps: S1: Use a zeroing calibration fixture to zero and calibrate five LVDT displacement sensors, and then use upper gap sample, middle gap sample and lower gap sample respectively to verify the accuracy of the measuring equipment; S2: Install the electric power steering system booster onto the housing support fixture, start the equipment to press down the housing of the electric power steering system booster with the upper pressure head, and ensure that the five LVDT displacement sensors contact the three evenly distributed points on the upper surface of the lower rotor and the two relative position points on the upper surface of the PHA respectively. S3: Collect the measured data from five LVDT displacement sensors and record them as the values ​​of the first to fifth sensors respectively; S4: Subtract the value of the first sensor from the values ​​of the third sensor, the fourth sensor, and the fifth sensor respectively, and subtract the value of the second sensor from the values ​​of the third sensor, the fourth sensor, and the fifth sensor respectively, to obtain six sets of difference data; S5: Extract the maximum and minimum values ​​from the six sets of differences. If both are within the range of 4.161 mm to 4.933 mm, the product is deemed qualified.

3. The method for detecting and judging the quality of air gap in EPS boosters according to claim 2, characterized in that, In step S2, after the upper pressure head presses down on the housing of the electric power steering system booster, a stability judgment step is also included: The system monitors the output values ​​of five LVDT displacement sensors. If the fluctuation of the reading of each sensor is less than the set threshold within a preset time interval, the measurement state is determined to be stable, and step S3 is executed. If the reading of any sensor fluctuates beyond the set threshold within a preset time interval, the upper pressure head will rise, and the system will issue a prompt signal, indicating that the lower rotor and PHA surface should be cleaned again or the electric power steering system booster should be reinstalled and the measurement repeated.

4. The method for detecting and judging the quality of air gap in EPS boosters according to claim 3, characterized in that, In the stability judgment step, if the reading fluctuation exceeds the set threshold, the system automatically identifies and displays the specific sensor number and its corresponding measurement surface area where the fluctuation exceeds the limit; at the same time, the equipment controls the pressure head to rise to a safe height and lock it. After the operator completes targeted cleaning or reinstallation according to the prompts and confirms that the fault is resolved, the system can be manually reset before the measurement process can be restarted.

5. The method for detecting and judging the quality of air gap in EPS boosters according to claim 2, characterized in that, In step S1, when verifying the accuracy of the measuring equipment using upper, middle, and lower gap samples, the system automatically records and stores the data from multiple verification measurements of each sample, forming a long-term calibration history curve for the equipment. Before conducting formal product measurements, the system compares the current sample verification data with the historical calibration curve. If the current data deviates from the historical curve by more than the preset tolerance range, the system automatically prompts that the equipment needs to be maintained or recalibrated, and pauses the product measurement process.

6. The method for detecting and judging the quality of air gap in EPS boosters according to claim 5, characterized in that, When the system compares the current sample verification data with the historical calibration curve, it also establishes an independent historical performance sub-curve for the current verification data of each of the five LVDT displacement sensors and performs independent deviation analysis. When the system prompts that equipment maintenance or recalibration is required, it synchronously outputs and displays the independent deviation analysis results of each LVDT displacement sensor and identifies the specific sensor number suspected of performance degradation based on this.

7. The method for detecting and judging the quality of air gap in EPS boosters according to claim 6, characterized in that, After the system outputs and displays the independent deviation analysis results of each LVDT displacement sensor and identifies the specific sensor number suspected of performance degradation, the sensor suspected of performance degradation is independently recalibrated and verified using a zeroing calibration fixture. If the verification data of the sensor returns to normal after recalibration and matches the historical performance sub-curve, the abnormality mark of the sensor is cleared and it is allowed to continue to be used. If the data is still abnormal after recalibration, the system prompts that the abnormal sensor needs to be physically replaced or repaired. At the same time, the measurement process is automatically adjusted, and the data of the faulty sensor channel is temporarily blocked in subsequent product measurements, and the remaining valid sensor data is used for calculation and adjustment compensation.

8. The method for detecting and judging the quality of air gap in EPS boosters according to claim 7, characterized in that, The calculation and adjustment compensation using the remaining valid sensor data are performed as follows: The system detects and confirms the channel number of the shielded faulty sensor, and identifies the original measurement object attribute of the faulty sensor. More specifically, it identifies that the sensor was originally used to measure the lower rotor surface or the PHA surface. Based on the layout of the remaining valid sensors and their measurement objects, the set of valid measurement points is reconstructed. If the failed sensor was originally used to measure the lower rotor surface, the data of the remaining two lower rotor measurement points are used, combined with their known theoretical 120-degree uniform distribution angle, and the height and inclination of the plane where it is located are fitted by the least squares method, and then the height value of the original third point's theoretical position is calculated. If the failed sensor was originally used to measure the PHA surface, only the data of the remaining one PHA measurement point is used, and it is directly used as the representative height value of the PHA surface. Substitute the calculated theoretical or representative values, along with the measured values ​​from the other effective sensors, into the original calculation process. The data processing unit continues to perform the original many-to-many differential calculation, subtracting the data from the three lower rotor measurement points from the data from the two PHA measurement points. The lower rotor measurement point data includes the actual measured value and the theoretical value obtained through calculation when necessary, while the PHA measurement point data includes the actual measured value and the representative value determined when necessary. This results in six sets of difference data, from which the maximum and minimum values ​​are extracted for qualification judgment.

Images