Method for detecting center diameter of cage pocket of cylindrical roller bearing

Abstract

A kind of detection method for cage pocket center diameter of cylindrical roller bearing, belong to rolling bearing detection technical field, based on the principle of coordinate measurement, the cage is placed on the measuring platform of coordinate measuring machine and stably supported, the workpiece rectangular coordinate system is constructed with the end face of cage as Z axis, the center line of outer diameter circle and pocket circle as X axis, Y axis is automatically generated by coordinate measuring machine and perpendicular to X axis and Z axis, respectively complete rough and fine construction of workpiece coordinate system, each pocket circle detection, pocket center circle fitting and size evaluation, finally get the actual size of cage pocket center diameter and determine whether it meets the design requirements. By constructing the workpiece rectangular coordinate system with unified reference and accurate positioning, and matching the standardized automated detection process, the direct and high-precision detection of the cylindrical roller cage pocket center diameter is realized, the detection process is standardized and highly repeatable, which effectively ensures the consistency and accuracy of the detection results and greatly improves the detection efficiency.

Description

Technical Field

[0001] This invention belongs to the field of rolling bearing testing technology, specifically relating to a method for testing the center diameter of the cage pocket of a cylindrical roller bearing. It is applicable to the high-precision direct testing of the center diameter of the cage pocket of various even-numbered and odd-numbered cylindrical roller cages, and can be widely used in the production quality inspection of cage batch processing and the product quality acceptance work in bearing application. Background Technology

[0002] The cylindrical roller cage is one of the four core components of a bearing (outer ring, inner ring, rolling elements, and cage). Through its pocket structure, it achieves circumferential separation, motion trajectory guidance, and uniform distribution of the rolling elements. It can effectively avoid direct contact and sliding friction between the rolling elements, reduce misalignment, vibration, and noise during bearing operation, achieve balanced load distribution, and reduce local stress concentration. It is a key component to ensure the efficient and reliable operation of cylindrical roller bearings under complex working conditions.

[0003] The center diameter of the pockets is a core parameter for measuring the geometric accuracy of cylindrical roller cages. It is the diameter of the theoretical circle formed by the centers of all the pockets on the cage that house the rollers. The accuracy of this parameter directly determines the positioning accuracy of the rollers within the cage. Machining errors in the center diameter of the pockets can easily lead to roller misalignment, increased radial runout of the bearing, and a significant reduction in the bearing's motion accuracy, load-bearing capacity, and fatigue life. Therefore, accurate and reliable testing of the center diameter of the cage pockets is a crucial step in controlling the machining quality of the cage and improving the overall performance of the bearing.

[0004] In existing technologies, the detection of the center diameter of the pocket often involves inserting a measuring column into symmetrical pockets, measuring the inner and outer dimensions of the measuring column with calipers, and then converting the result to the center diameter. This method has significant drawbacks: First, there is a gap between the measuring column and the pocket, and the calipers themselves have limited measurement accuracy, leading to low reliability of the measurement results. Second, for cages with an odd number of pockets, this method cannot achieve effective detection because the pockets are not symmetrical. Third, traditional methods lack standardized coordinate system construction specifications, resulting in inconsistent measurement benchmarks and further amplifying measurement errors. Fourth, the measurement process lacks a unified standard, leading to significant human error due to manual operation, making it difficult to meet the efficiency requirements of batch testing. These problems make traditional detection methods unsuitable for the current bearing industry's demand for high-precision, universal, and standardized cage testing. Developing a method for detecting the center diameter of cylindrical roller cage pockets with a unified benchmark, standardized process, and adaptability to various pocket numbers has become an urgent technical problem to be solved in the industry. Summary of the Invention

[0005] To address the problems of low measurement accuracy, poor versatility, inconsistent benchmarks, inability to adapt to odd-numbered pocket cages, and low inspection efficiency in existing cylindrical roller cage pocket center diameter testing methods, this invention proposes a new method for testing the center diameter of pockets in cylindrical roller bearing cages. This invention constructs a standardized workpiece rectangular coordinate system with a clearly defined shaft reference and precise origin positioning. Combining manual coarse and automatic fine coordinate system construction methods, along with a standardized pocket circle inspection process and a precise center circle fitting evaluation method, this method enables direct and high-precision testing of the center diameter of pockets in various types of cylindrical roller cages. This effectively improves the reliability and efficiency of the testing results, meeting the quality inspection requirements of cage mass production and the installation and usage needs of mainframe users.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for detecting the center diameter of the cage pocket of a cylindrical roller bearing. The detection method is based on the coordinate measuring principle. According to the product size and accuracy requirements of the cage to be tested, a coordinate measuring machine with appropriate accuracy is selected. The cage is placed on the measuring platform of the coordinate measuring machine and stably supported. A workpiece rectangular coordinate system is constructed with the end face of the cage as the Z-axis and the line connecting the center of the outer diameter circle and the pocket circle as the X-axis. The Y-axis is automatically generated by the coordinate measuring machine and is perpendicular to both the X-axis and the Z-axis. The rough and fine construction of the workpiece coordinate system, the detection of each pocket circle, the fitting of the pocket center circle and the size evaluation are completed in sequence. Finally, the actual size of the center diameter of the cage pocket is obtained and it is determined whether it meets the design requirements.

[0007] The origin of the workpiece rectangular coordinate system is located at the center of the projection circle of the cage diameter circle on its end face. The coordinate system is constructed in a surface-circle-circle manner, completing the two stages of manual rough construction and automatic fine construction in sequence. The finely constructed coordinate system is the only measurement reference for the entire inspection process.

[0008] The specific operation of manually coarsely establishing the coordinate system includes: in manual mode, collecting the planar elements of the upper end face of the cage, the circular elements of the outer diameter circle of the cage, and the circular elements of the pocket circle of any pocket, to form the reference plane, the outer diameter reference circle, and the pocket reference circle, respectively; with the reference plane as the Z-axis and the line connecting the center of the outer diameter reference circle and the pocket reference circle as the X-axis, the coordinate measuring machine automatically generates the Y-axis that is perpendicular to both the X and Z axes, thus completing the coarse establishment of the rectangular coordinate system and realizing the initial positioning of the cage.

[0009] The specific operation of the automatic coordinate system construction includes: using the automatic program function of the coordinate measuring machine, collecting eight or more measurement points on the end face of the cage to generate a high-precision reference plane, collecting eight or more measurement points on the outer diameter circular surface of the cage to generate a high-precision outer diameter reference circle, and collecting four or more measurement points on the pocket circular surface at the same position as during the rough coordinate system construction to generate a high-precision pocket reference circle; using the surface-circle-circle method, with the high-precision reference plane as the Z-axis and the line connecting the centers of the high-precision outer diameter reference circle and the high-precision pocket reference circle as the X-axis, the coordinate measuring machine automatically generates a Y-axis that is perpendicular to both the X and Z axes, thus completing the fine construction of the rectangular coordinate system and improving the positioning accuracy of the coordinate system.

[0010] The inspection of each pocket circle must be completed at the same axial position as the coordinate system. The specific operation includes: using the finely constructed workpiece rectangular coordinate system as a reference, selecting the first pocket of the cage, setting uniform pocket measurement parameters and compiling a single pocket measurement program, running the program to collect feature points to complete the measurement, and obtaining the parameter information φ1 of the first pocket circle; and sequentially completing the measurement of all other pockets according to the same parameters and program compilation method to obtain the parameter information φ2, φ3...φn of the remaining pocket circles, where n is the total number of pockets of the cage.

[0011] The unified pocket measurement parameters include at least the number of pocket circle feature points collected, and the programming logic and feature point collection methods for all pocket circle detections are consistent to ensure measurement standardization.

[0012] The specific operations for fitting and evaluating the size of the pocket center circle include: using the construction function of the coordinate measuring machine software, selecting all measured pocket circle parameter information φ1, φ2, φ3...φn, and fitting the cage pocket center circle φD with the finely constructed workpiece rectangular coordinate system as the reference; evaluating the diameter of the pocket center circle φD through the size evaluation function of the coordinate measuring machine to obtain the actual diameter size △Ds of the pocket center circle; comparing △Ds with the standard diameter size △D0 of the pocket center circle required by the product design or host user, and determining whether the cage pocket center diameter meets the usage requirements based on the comparison results.

[0013] The detection method of the present invention is a direct measurement method, which eliminates the need to convert the center diameter size through the measuring column, effectively eliminating the detection error caused by the gap between the measuring column and the pocket and the low measurement accuracy of the caliper.

[0014] The beneficial effects of this invention are: Standardized coordinate system datum and precise positioning improve measurement accuracy from the source: This invention clearly defines the datum and origin positions of each axis of the coordinate system. The end face of the cage is the Z-axis, the line connecting the center of the outer diameter circle and the pocket circle is the X-axis, the Y-axis is automatically generated and perpendicular to the X and Z axes, and the origin is located at the center of the projection circle of the cage diameter circle on the end face. The entire process is constructed using a surface-circle-circle method. Combined with manual rough construction and automatic fine construction, the standardization of the measurement datum and the precision of the positioning are achieved. This completely solves the measurement error problem caused by the lack of uniformity of the datum in traditional methods, laying a core foundation for high-precision detection.

[0015] Achieving direct measurement and overcoming industry testing limitations: This invention abandons the traditional measurement column conversion method and directly collects the pocket circle feature points and fits the pocket center circle through a coordinate measuring machine. This effectively eliminates errors caused by the gap between the measurement column and the pocket and the low accuracy of caliper measurement. At the same time, it is applicable to various cylindrical roller cages with even-numbered pockets and odd-numbered pockets, and completely solves the industry pain point that traditional methods cannot detect cages with odd-numbered pockets.

[0016] The testing process is standardized and regulated, resulting in highly reliable results: This invention establishes a unified standard for pocket circle testing. All pockets are tested in the same axial position with the same parameters and procedures. The feature point acquisition method and program programming logic are consistent, and the pocket center circle is generated by fitting all pocket circles. This minimizes human error caused by manual operation and ensures the accuracy, consistency, and reliability of the measurement results, meeting the testing requirements of high-precision cages.

[0017] High inspection efficiency and suitable for batch production needs: This invention can realize the automated operation of coordinate system fine construction and pocket circle inspection through the automatic program function of coordinate measuring machine. The measurement program can be repeatedly compiled and run without repeated manual debugging, which greatly improves the inspection efficiency of pocket center diameter, reduces the labor intensity of manual inspection, and perfectly meets the production inspection needs of cage batch processing.

[0018] With strong versatility and wide application scenarios, this invention provides end-to-end quality assurance: The testing method of this invention is not limited by the number of cage pockets, adapts to the testing needs of various cylindrical roller cages, and can be directly applied to the product processing quality inspection of cage manufacturers, as well as the product quality acceptance of bearing users. It provides strong technical support for manufacturing units to control product precision, and provides reliable quality assurance for the installation and use of main equipment users, which helps to improve the overall assembly accuracy and performance of cylindrical roller bearings. Attached Figure Description

[0019] Figure 1 This is a flowchart of the detection method of the present invention.

[0020] Figure 2This is a schematic diagram of the data acquisition operation for manually establishing a rough coordinate system.

[0021] Figure 3 A schematic diagram of the data acquisition operation for automatically establishing a coordinate system.

[0022] Figure 4 This is a schematic diagram of the operation for detecting the first pocket circle.

[0023] Figure 5 This is a schematic diagram of the operation for detecting the second pocket circle. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figures 1-5 Taking a certain type of cylindrical roller cage as the test object, this cage has 20 pockets. The design requirement for the center diameter of the pockets is φ695±0.05mm. The test method of this invention is used to directly measure the center diameter of the pockets. The coordinate system is with the upper end face of the cage as the Z-axis, the line connecting the center of the outer diameter circle and any pocket circle as the X-axis, and the Y-axis automatically generated by the coordinate measuring machine and perpendicular to both the X and Z axes. The origin is located at the center of the projection circle of the cage diameter circle on its upper end face. The specific implementation steps are as follows: Preparations before S1 testing: Based on the product dimensions (outer diameter 720mm) and the required inspection accuracy (±0.05mm) of the cage, a suitable high-precision coordinate measuring machine is selected. The cage is placed stably on the measuring platform of the coordinate measuring machine, and the bottom surface of the cage is stably supported, ensuring that all pockets of the cage face upwards, so as to ensure that the cage does not shift or shake during the inspection process. The coordinate measuring machine is started and the matching measurement software is run to complete the preliminary preparation work such as probe calibration and equipment zeroing, ensuring that the equipment is in normal inspection condition.

[0026] Construction of the rectangular coordinate system for workpiece S2: (1) Manual rough construction: In the manual mode of the coordinate measuring machine, collect 4 measurement points on the upper surface of the 20 pocket beams on the upper end face of the cage, generate plane elements and form a reference plane (Z-axis reference); collect 4 measurement points at the same axial position on the outer diameter surface of the cage, generate circle elements and form an outer diameter reference circle; collect 4 measurement points at the same axial position on the inner surface of any pocket of the cage, generate circle elements and form a pocket reference circle; adopt the surface-circle-circle construction method, with the reference plane as the Z-axis and the line connecting the center of the outer diameter reference circle and the pocket reference circle as the X-axis, the coordinate measuring machine automatically generates Y-axis that is perpendicular to both X and Z axes, and roughly constructs the rectangular coordinate system A1, with the origin located at the center of the projection circle of the cage diameter circle on its upper end face, to achieve the initial positioning of the cage.

[0027] (2) Automatic fine construction: Using the automatic program function of the coordinate measuring machine, 20 measurement points (eight or more) are collected on the upper surface of the twenty pocket beams on the upper end face of the cage, generating planar elements and forming a high-precision reference plane (Z-axis); 16 measurement points (eight or more) are collected at the same axial position as the outer diameter surface of the cage when the coordinate system is coarsely constructed, generating circular elements and forming a high-precision outer diameter reference circle; 6 measurement points (four or more) are collected at the same axial position as the inner surface of the same pocket when the coordinate system is coarsely constructed, generating circular elements and forming a high-precision pocket reference circle; using the surface-circle-circle construction method, with the high-precision reference plane as the Z-axis and the line connecting the center of the high-precision outer diameter reference circle and the high-precision pocket reference circle as the X-axis, the coordinate measuring machine automatically generates Y-axis that is perpendicular to both the X and Z axes, finely constructing the rectangular coordinate system A2, with the origin consistent with the coordinate system A1, improving the positioning accuracy of the coordinate system, and using the coordinate system A2 as the only measurement reference for this inspection.

[0028] Standardized hole-by-hole inspection of S3 pocket circle: Using the refined rectangular coordinate system A2 as a reference, standardized hole-by-hole inspection was performed on the 20 pockets of the cage at the same axial position as the coordinate system: the first pocket was selected, and the unified measurement parameters were set to collect 8 feature points on the inner surface of the pocket circle. A single pocket measurement program was compiled, and the program was run to complete the feature point collection and generate the parameter information φ1 of the first pocket circle; given a coordinate movement point, the coordinate measuring machine probe was accurately moved to above the second pocket, and the same measurement parameters, program compilation logic and feature point collection method were used to compile and run the measurement program to generate the parameter information φ2 of the second pocket circle; the above steps were repeated to complete the standardized inspection of the remaining 18 pockets and generate the parameter information φ3, φ4...φ20 of the pocket circles.

[0029] Fitting and determination of the detection results of the center circle of the S4 pocket: Using the circle construction function of the coordinate measuring machine (CMM) software, the parameter information of 20 pocket circles (φ1, φ2...φ20) were selected. Based on the precisely constructed rectangular coordinate system A2, the center circle φD of the pockets of the cage was fitted and generated. Through the dimensional evaluation function of the CMM, the diameter of the center circle φD of the pockets was accurately measured, and the actual diameter ΔDs was found to be φ695.017mm. The actual size was compared with the standard size φ695±0.05mm required by the design. The actual size was within the standard tolerance range, and the center diameter of the pockets of the cage was directly judged to be qualified.

[0030] Example Detection Data Table of Test Data for the Center Diameter of Pocket Holes of a Certain Type of Cylindrical Roller Cage

[0031] The detection method of this invention achieves direct and high-precision detection of the center diameter of the pocket of cylindrical roller cage by constructing a workpiece rectangular coordinate system with unified benchmark and precise positioning, and combining it with a standardized automated detection process. The detection process is standardized and highly repeatable, effectively ensuring the consistency and accuracy of the detection results, and greatly improving the detection efficiency. It is suitable for large-scale application in the production and detection of various cylindrical roller cages.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0033] The parts of this invention not described in detail are prior art.

Claims

1. A method for detecting the center diameter of the cage pocket of a cylindrical roller bearing, characterized in that: The detection method is based on the principle of coordinate measurement. According to the product size and accuracy requirements of the cage to be tested, a coordinate measuring machine with appropriate accuracy is selected. The cage is placed on the measuring platform of the coordinate measuring machine and stably supported. A rectangular coordinate system of the workpiece is constructed with the end face of the cage as the Z-axis and the line connecting the center of the outer diameter circle and the pocket circle as the X-axis. The Y-axis is automatically generated by the coordinate measuring machine and is perpendicular to both the X-axis and the Z-axis. The coarse and fine construction of the workpiece coordinate system, the detection of each pocket circle, the fitting of the pocket center circle and the size evaluation are completed in sequence. Finally, the actual size of the center diameter of the cage pocket is obtained and it is determined whether it meets the design requirements.

2. The method for detecting the center diameter of the cage pocket of a cylindrical roller bearing according to claim 1, characterized in that: The origin of the workpiece rectangular coordinate system is located at the center of the projection circle of the cage diameter circle on its end face. The coordinate system is constructed in a surface-circle-circle manner, completing the two stages of manual rough construction and automatic fine construction in sequence. The finely constructed coordinate system is the only measurement reference for the entire inspection process.

3. The method for detecting the center diameter of the cage pocket of a cylindrical roller bearing according to claim 2, characterized in that: The specific operation of manually coarsely establishing the coordinate system includes: in manual mode, collecting the planar elements of the upper end face of the cage, the circular elements of the outer diameter circle of the cage, and the circular elements of the pocket circle of any pocket, to form the reference plane, the outer diameter reference circle, and the pocket reference circle, respectively; with the reference plane as the Z-axis and the line connecting the center of the outer diameter reference circle and the pocket reference circle as the X-axis, the coordinate measuring machine automatically generates the Y-axis that is perpendicular to both the X and Z axes, thus completing the coarse establishment of the rectangular coordinate system and realizing the initial positioning of the cage.

4. The method for detecting the center diameter of the cage pocket of a cylindrical roller bearing according to claim 2, characterized in that: The specific operation of the automatic coordinate system construction includes: using the automatic program function of the coordinate measuring machine, collecting eight or more measurement points on the end face of the cage to generate a high-precision reference plane, collecting eight or more measurement points on the outer diameter circular surface of the cage to generate a high-precision outer diameter reference circle, and collecting four or more measurement points on the pocket circular surface at the same position as during the rough coordinate system construction to generate a high-precision pocket reference circle; using the surface-circle-circle method, with the high-precision reference plane as the Z-axis and the line connecting the centers of the high-precision outer diameter reference circle and the high-precision pocket reference circle as the X-axis, the coordinate measuring machine automatically generates a Y-axis that is perpendicular to both the X and Z axes, thus completing the fine construction of the rectangular coordinate system and improving the positioning accuracy of the coordinate system.

5. The method for detecting the center diameter of the cage pocket of a cylindrical roller bearing according to claim 1, characterized in that: The inspection of each pocket circle must be completed at the same axial position as the coordinate system. The specific operation includes: using the finely constructed workpiece rectangular coordinate system as a reference, selecting the first pocket of the cage, setting uniform pocket measurement parameters and compiling a single pocket measurement program, running the program to collect feature points to complete the measurement, and obtaining the parameter information φ1 of the first pocket circle; and sequentially completing the measurement of all other pockets according to the same parameters and program compilation method to obtain the parameter information φ2, φ3...φn of the remaining pocket circles, where n is the total number of pockets of the cage.

6. The method for detecting the center diameter of the cage pocket of a cylindrical roller bearing according to claim 5, characterized in that: The unified pocket measurement parameters include at least the number of pocket circle feature points collected, and the programming logic and feature point collection methods for all pocket circle detections are consistent to ensure measurement standardization.

7. The method for detecting the center diameter of the cage pocket of a cylindrical roller bearing according to claim 1, characterized in that: The specific operations for fitting and evaluating the size of the pocket center circle include: using the construction function of the coordinate measuring machine software, selecting all measured pocket circle parameter information φ1, φ2, φ3...φn, and fitting the cage pocket center circle φD with the finely constructed workpiece rectangular coordinate system as the reference; evaluating the diameter of the pocket center circle φD through the size evaluation function of the coordinate measuring machine to obtain the actual diameter size △Ds of the pocket center circle; comparing △Ds with the standard diameter size △D0 of the pocket center circle required by the product design or host user, and determining whether the cage pocket center diameter meets the usage requirements based on the comparison results.

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