Rolling bearing friction torque measuring machine capable of actively eliminating system errors and measuring method

Abstract

The invention discloses a rolling bearing friction torque measuring machine capable of actively eliminating system errors and a measuring method, the rolling bearing friction torque measuring machine comprises an equipment table, a frame body, a bearing seat and a main shaft, the bearing seat is provided with an inner cavity, a bearing cabin is arranged in the inner cavity, the main shaft and the bearing cabin are connected with a to-be-detected bearing, and a balance structure is arranged on the bearing cabin. The main shaft and the bearing seat are connected with a supporting bearing, a detection structure is arranged on the frame body, a driving structure is arranged on the equipment table, and the detection method comprises the following steps that S1, the bearing is installed; s2, measuring the total torque; and S3, calculating a real friction torque. The problems that a measurement result of a traditional rolling bearing friction torque measurement device is easily interfered by system errors such as rotating shaft misalignment, bearing installation errors and supporting bearing friction, the measurement precision is low, and small friction torque changes of small and medium-sized bearings under complex working conditions are difficult to recognize are solved.

Description

Technical Field

[0001] This invention relates to the field of bearing measurement equipment technology, specifically to a rolling bearing friction torque measuring machine and method that actively eliminates systematic errors. Background Technology

[0002] Rolling bearings are core friction components in mechanical systems and are widely used in aerospace, new energy vehicles, precision machine tools and other fields. Their friction torque directly determines transmission efficiency, operational stability and service life. Accurate measurement is the core prerequisite for bearing performance optimization and life prediction, and it is also an important support for ensuring the independent control of key basic components.

[0003] Currently, mainstream measurement technologies are divided into two categories: direct measurement (torque sensor mounted on the shaft) and indirect measurement (balancing method, transmission method). Although they can complete basic data acquisition, they have obvious technical limitations and cannot meet the requirements of high-precision, full-condition measurement: First, system error interference is significant. Non-measured factors such as shaft misalignment, bearing friction, and installation deviations can mask the true friction torque, making it particularly difficult to adapt to small and medium-sized high-precision bearings. Second, measurement accuracy and stability are insufficient. The lack of precise balance calibration and tooling and counterweight errors exacerbate deviations, making it impossible to identify subtle differences in bearing friction performance. Third, the adaptability to operating conditions is poor, making it difficult to cover full lubrication conditions. Unreasonable axial force application and monitoring structures can easily generate measurement interference. Fourth, there is structural redundancy. Improper loading structure arrangement affects shaft stability, and the lack of modular design makes it difficult to adapt to extreme operating conditions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a rolling bearing friction torque measuring machine and method that actively eliminates systematic errors. This solves the problems of traditional rolling bearing friction torque measuring devices being easily affected by systematic errors such as shaft misalignment, bearing installation errors, and support bearing friction, as well as low measurement accuracy and difficulty in identifying minute changes in friction torque under complex working conditions or in small and medium-sized bearings.

[0005] To achieve the above objectives, the present invention provides a rolling bearing friction torque measuring machine that actively eliminates systematic errors, comprising an equipment platform and a frame mounted on the equipment platform. The frame is provided with a bearing housing and a main shaft. The bearing housing has an inner cavity, within which a bearing housing is provided for mounting on the main shaft. At least one bearing to be tested is detachably connected between the outer peripheral wall of the main shaft and the inner peripheral wall of the bearing housing. The bearing housing is provided with a balancing structure for applying a stable radial load to the bearing to be tested and calibrating the overall balance to reduce manufacturing and counterweight errors. Support bearings for supporting the stable rotation of the main shaft are rotatably connected to both ends of the main shaft and the bearing housing. The bearing housing and the balancing structure are combined to form a floating structure. The frame is provided with a detection structure for capturing torque signals and axial force signals to provide data support for calculating the true friction torque of the bearing to be tested. The equipment platform is provided with a drive structure for driving the main shaft to rotate in both forward and reverse directions.

[0006] The advantages of adopting the above technical solution are as follows: The equipment platform and frame construct a stable installation foundation, providing reliable support for subsequent functional components. The nested design of the bearing housing and bearing compartment enables precise placement and rapid assembly / disassembly of the bearing to be tested, adapting to the measurement needs of bearings of different specifications and quantities. The aforementioned balancing structure applies a stable radial load to the bearing to be tested while calibrating the overall balance to reduce manufacturing and counterweight errors, improving initial measurement accuracy. The support bearing ensures stable rotation of the spindle, avoiding additional interference caused by shaft wobbling. The floating structure formed by the combination of the bearing compartment and the balancing structure effectively isolates the frictional interference of the support bearing, allowing the testing structure to respond only to the torque of the bearing to be tested. The signal eliminates the influence of non-measured factors on the measurement results; the above detection structure can simultaneously capture torque signals and axial force signals, providing accurate data support for calculating the true friction torque of the bearing under test, while the drive structure drives the spindle to rotate in both directions, and with the error elimination algorithm, it can actively eliminate installation errors, further improving the accuracy of the measurement results; through the design of the above overall structure, the overall modularity is high, which can be adapted to the high-precision measurement needs of aerospace, new energy vehicles, precision machine tools and other fields, solving the technical problems of significant system errors, insufficient accuracy and poor adaptability of traditional measurement devices, providing reliable data support for bearing performance optimization and life prediction, and ensuring the independent control of key basic components.

[0007] The invention further includes the following configuration: two symmetrical balance beams are arranged on the outer peripheral wall of the bearing housing; limit grooves are formed on both side walls of the bearing seat; the two balance beams pass through their respective adjacent limit grooves; a connecting arm is detachably provided at the center of each balance beam; a weight for applying a downward force to the balance beam is detachably provided at the end of the connecting arm; the end of the balance beam is integrally formed with the bearing housing; the detection structure includes two force sensors, which are respectively located on both sides of the frame; the two balance beams are positioned corresponding to the two force sensors; the starting end of each balance beam is in contact with the detection end of the corresponding force sensor; a first slide rail is provided on the frame along the length of each balance beam corresponding to the two balance beam positions; a base plate is slidably provided on the first slide rail along the length of the balance beam, and a number of first bolts are detachably connected between the base plate and the first slide rail; a second slide rail is provided on the base plate along the width of the balance beam; a base is slidably provided on the second slide rail, and a number of second bolts are detachably connected between the base and the second slide rail; the base is detachably connected to the force sensor.

[0008] The advantages of adopting the above technical solution are as follows: The symmetrical arrangement of two balance beams on the outer periphery of the bearing housing improves the force balance and avoids structural skew caused by unilateral loads. The limiting grooves on both sides of the bearing housing limit redundant displacement of the balance beams, ensuring the accuracy of structural movement. The detachable connecting arm at the center of the balance beam allows for flexible adjustment of the weight suspension position to adapt to different radial load application requirements. The weight at the end of the connecting arm can apply radial loads stably by gravity, avoiding fluctuations caused by hydraulic or pneumatic loading. The design of the balance beam end being integrally formed with the bearing housing improves structural rigidity and reduces losses during force transmission. The two force sensors in the detection structure are correspondingly set with the two balance beams, accurately capturing the force couple signals on both sides, improving the comprehensiveness of data acquisition, and ensuring balance. The contact arrangement between the beam's starting end and the force sensor's detection end ensures direct transmission of force signals and reduces signal attenuation. The first slide rail and base plate on the frame allow adjustment of the force sensor position along the length of the balance beam, accommodating sensor installation requirements with different ranges. The second slide rail and base plate on the base plate allow adjustment of the force sensor position along the width of the balance beam, precisely controlling the preload. The detachable connection of the first and second bolts enables fixing and fine-tuning of the sensor position, improving measurement flexibility. Simultaneously, the dual-slide rail adjustment structure can accommodate force sensors of different specifications, enhancing the equipment's versatility. The symmetrically arranged balance beam and force sensor effectively offset tooling manufacturing errors, improving measurement accuracy. The modular design of the overall structure facilitates subsequent maintenance and upgrades, further adapting to measurement needs under extreme working conditions.

[0009] The present invention further comprises: a support frame is provided at the bottom of the connecting arm and a weight is provided in the support frame; a plurality of swing arms are rotatably connected to the top wall of the support frame; each swing arm is provided with a swing groove; a fixing pin is provided on the outer peripheral wall at the bottom of the connecting arm corresponding to the position of each swing arm; each fixing pin is movably provided in the corresponding swing groove; and the plurality of swing arms are arranged in pairs and respectively on both sides of the connecting arm.

[0010] The advantages of adopting the above technical solution are as follows: The support frame set at the bottom of the connecting arm can stably place the weight, avoiding load fluctuations caused by weight swaying. The several swing arms rotatably connected to the top wall of the support frame can achieve adaptive suspension through the cooperation of the swing groove and the fixed pin. When the weight is tilted due to external force, the swing arm can swing along the fixed pin to automatically adjust the position of the weight and ensure the stability of the applied load. The design of several swing arms being arranged in pairs on both sides of the connecting arm improves the symmetry of the structure and further enhances the load balance. The movable connection of the swing groove and the fixed pin can adapt to the small displacement during the weight suspension process and reduce stress concentration during load transmission. The adaptive adjustment function of the above overall structure can effectively reduce measurement errors caused by uneven load, improve the reliability of data acquisition, and lay the foundation for accurate calculation of the true friction torque. At the same time, the design of this structure can also adapt to weights of different weights, enhance the load adaptability of the equipment, and further improve the adaptability to working conditions.

[0011] The present invention further includes: a fine-tuning hole is provided on the end wall of the starting end of the balance beam, and a balance bolt is threaded into the fine-tuning hole for fine-tuning the horizontal attitude of the balance beam so that the floating structure composed of the bearing housing and the balance beam is in a state of mechanical equilibrium.

[0012] The advantages of adopting the above technical solution are as follows: The balance beam, with its fine-tuning hole at the beginning and threaded connection to the balance bolt, allows for precise fine-tuning of its horizontal posture. This counteracts machining and counterweight errors during tooling manufacturing, reducing the impact of tooling manufacturing errors, material inconsistencies, and weight errors of the weights on both sides. This ensures the floating structure composed of the bearing housing and the balance beam is in mechanical equilibrium, thereby reducing the initial reading differences of the force sensors on both sides and improving initial measurement accuracy. The threaded connection of the balance bolt allows for minute adjustments, ensuring the accuracy of the balance posture and preventing structural deformation caused by over-adjustment. The fine-tuning hole also prevents interference between the balance bolt and other components, improving structural rationality. Furthermore, the fine-tuning function of the balance bolt allows for rapid equipment calibration before measurement, reducing preparation time and improving measurement efficiency.

[0013] The present invention further comprises: a mounting hole through which the bearing housing accommodates the main shaft and the bearing to be tested; a shoulder is circumferentially provided on the inner peripheral wall of the mounting hole; a linear elastic ring is provided between the inner wall of the shoulder and the adjacent bearing to be tested; the detection structure further comprises a plurality of strain gauges for detecting the axial force data of the bearing to be tested; the strain gauges are mounted on the linear elastic ring.

[0014] The advantages of adopting the above technical solution are as follows: the shoulder circumferentially set on the inner circumferential wall of the mounting hole can accurately position the linear elastic ring, ensuring close contact between the linear elastic ring and the bearing under test. The linear elastic ring can transmit axial force and ensure uniform force distribution, avoiding measurement errors caused by local stress concentration. The strain gauge is installed on the linear elastic ring, which can accurately monitor the axial force data of the bearing under test, providing key parameters for full-condition measurement. The overall structure design can be adapted to measurement scenarios with different axial force requirements, enhancing the adaptability of the equipment to different operating conditions and providing data support for comprehensive evaluation of bearing performance. At the same time, the modular design of this structure facilitates subsequent maintenance and upgrades, further improving the reliability and service life of the equipment.

[0015] The present invention further comprises: the drive structure including a drive motor and an elastic coupling, wherein the output end of the drive motor is coaxially connected to the beginning end of the main shaft through the elastic coupling.

[0016] The advantages of adopting the above technical solution are: the drive motor provides stable power to ensure the smooth operation of the spindle, while the flexible coupling can buffer the impact and vibration during the transmission process, reduce torque fluctuations, and avoid measurement errors caused by transmission interference; the forward and reverse rotation function of the drive structure, combined with the error elimination algorithm, can actively eliminate installation errors, improve the accuracy of measurement results, and the selection of the drive motor can be adapted to measurement scenarios with different speed requirements, enhancing the adaptability of the equipment to working conditions.

[0017] The present invention further includes a measurement method comprising the following steps: S1. Install the bearing to be tested and install weights of the corresponding specifications according to the data requirements; S2. Start the drive motor to drive the spindle to rotate clockwise and record the measured readings of the two force sensors and calculate the center distance between the two force sensors and the spindle. Based on the measured readings and center distance, obtain the first total torque using the overall friction torque formula. Switch the drive motor to drive the spindle to rotate counterclockwise and record the measured readings of the two force sensors and calculate the center distance between the two force sensors and the spindle. Based on the measured readings and center distance, obtain the second total torque using the overall friction torque formula. S3. If there is only one bearing to be tested, the first total torque and the second total torque are used to calculate the true friction torque of the bearing to be tested using the first true friction torque formula. If there are two bearings to be tested, the first total torque and the second total torque are used to calculate the true friction torque of the bearing to be tested using the second true friction torque formula.

[0018] The present invention further specifies that the formula for the overall frictional torque in step S2 is: , The two center distance data are respectively and The two measured readings are respectively and ,in and The data represents the preload readings of the force sensor; the calculation result of the first total torque obtained from the overall friction torque formula using two center distance data, two measured readings, and two preload readings when the spindle rotates clockwise is as follows: The calculation result of the first total torque when the spindle rotates counterclockwise, obtained from two center distance data, two measured readings, and two preload readings using the overall friction torque formula, is as follows: .

[0019] The present invention further includes the following configuration: if the number of bearings to be tested is two and the spindle rotates clockwise... ; If the number of bearings to be tested is two and the spindle rotates counterclockwise, ; in and The internal torque generated during the installation of the bearing to be tested is denoted as . and These are the actual frictional torque values ​​of the two bearings under test, as stated above. and Two measured readings when the spindle rotates clockwise. and The preload readings of the two force sensors before the spindle rotates clockwise are as follows: and Two measured readings when the spindle rotates counterclockwise. and The data is the preload readings of the two force sensors before the spindle rotates counterclockwise.

[0020] The present invention further specifies that the actual frictional torque of the bearing to be tested is: , If there are two bearings to be tested, the actual frictional torque value of a single bearing is expressed as follows: ; If there is only one bearing to be tested, then the actual frictional torque value of the bearing to be tested is expressed as follows:

[0021] The advantages of adopting the above technical solution are as follows: The measurement method, through the steps of installing the bearing to be tested and, according to requirements, installing weights of corresponding specifications, can flexibly adapt to bearings of different sizes and quantities, and radial load requirements of different magnitudes, improving the equipment's versatility and adaptability to different working conditions. The step of driving the main shaft to rotate in both forward and reverse directions with the drive motor and recording the measured data from the force sensor and the center distance data can comprehensively capture the force couple signals under different directions of rotation, providing complete raw data support for subsequent error elimination. Furthermore, the step of calculating the first and second total torques using the overall friction torque formula can accurately quantify the total friction effect under different directions of rotation, and, combined with the number of bearings to be tested, select the corresponding actual friction torque. The design of the friction torque formula can actively eliminate installation errors by utilizing the reverse superposition characteristics of internal torque during forward and reverse rotation, effectively separating the actual friction torque from the installation error. The calculation logic designed separately for one or two bearings under test can ensure the accuracy and reliability of measurement results under different installation scenarios, providing core data support for bearing performance optimization and life prediction. The entire method is compact and logically rigorous, with strong ease of operation, which can significantly improve measurement efficiency and accuracy, solve the technical problems of significant systematic errors, insufficient accuracy, and poor adaptability of traditional measurement methods, and provide reliable technical support for the performance evaluation of high-precision bearings in aerospace, new energy vehicles, precision machine tools and other fields. Attached Figure Description

[0022] Figure 1 This is a three-dimensional view of the present invention; Figure 2 This is a front sectional view of the present invention; Figure 3 for Figure 1 A partial 3D view after removing the equipment platform and frame; Figure 4 for Figure 3 A partial 3D view after removing the connecting arm and its linkage structure; Figure 5 This is a cross-sectional view of the bearing housing in this invention. Detailed Implementation

[0023] This invention provides a rolling bearing friction torque measuring machine that actively eliminates systematic errors, including a platform 1 and a frame 11 mounted on the platform 1. The frame 11 is provided with a bearing housing 12 and a main shaft 13. The bearing housing 12 has an inner cavity 121, within which a bearing chamber 2 is provided for mounting on the main shaft 13. At least one bearing 21 to be tested is detachably connected between the outer peripheral wall of the main shaft 13 and the inner peripheral wall of the bearing chamber 2. The bearing chamber 2 is provided with a balancing structure for applying a stable radial load to the bearing 21 to be tested and calibrating the overall balance to reduce manufacturing and counterweight errors. Both ends of the main shaft 13 are rotatably connected to the bearing housing 12 to support the stable rotation of the main shaft 13. The bearing housing 2 and the balance structure are combined to form an integral floating structure. The frame 11 is equipped with a detection structure for capturing force couple signals and axial force signals to provide data support for calculating the true friction torque of the bearing 21 under test. The equipment platform 1 is equipped with a drive structure for driving the main shaft 13 to rotate in both directions. Two balance beams 22 are provided on the outer peripheral wall of the bearing housing 2 and the two balance beams 22 are symmetrically arranged. Limiting grooves 122 are opened on both side walls of the bearing seat 12. The two balance beams 22 are respectively set through their adjacent limiting grooves 122. A connecting arm 3 is detachably provided at the center of the balance beam 22. The end of the connecting arm 3 is detachably provided with a tool for leveling. A weight 31 applies a downward force to the balance beam 22. The end of the balance beam 22 is integrally formed with the bearing housing 2. The detection structure includes two force sensors 4, which are respectively disposed on both sides of the frame 11. The two balance beams 22 are correspondingly positioned with the two force sensors 4. The starting end of the balance beam 22 is in contact with the detection end of the corresponding force sensor 4. A first slide rail 41 is provided on the frame 11 along the length of the balance beam 22 at the positions corresponding to the two balance beams 22. A base plate 42 is slidably disposed on the first slide rail 41 along the length of the balance beam 22, and the base plate 42 is detachably connected to the first slide rail 41 by several first bolts 421. The base plate 42 is slidably disposed along the width of the balance beam 22. A second slide rail 43 is provided in the degree direction. A base 44 is slidably mounted on the second slide rail 43, and a number of second bolts 441 are detachably connected between the base 44 and the second slide rail 43. The base 44 is detachably connected to the force sensor 4. A support frame 5 is provided at the bottom of the connecting arm 3, and a weight 31 is placed in the support frame 5. A number of swing arms 51 are rotatably connected to the top wall of the support frame 5. Each swing arm 51 has a swing groove 52. A fixing pin 32 is provided on the outer peripheral wall of the bottom of the connecting arm 3 corresponding to the position of each swing arm 51. Each fixing pin 32 is movably mounted in the corresponding swing groove 52. The number of swing arms 51 are arranged in pairs on both sides of the connecting arm 3.The balance beam 22 has a fine-tuning hole 221 on its initial end wall, and a balance bolt 222 is threaded into the fine-tuning hole 221 for fine-tuning the horizontal attitude of the balance beam 22 to ensure that the floating structure composed of the bearing housing 2 and the balance beam 22 is in mechanical equilibrium. The bearing housing 2 has a through-hole 23 for accommodating the main shaft 13 and the bearing 21 to be tested. A shoulder 24 is circumferentially arranged on the inner circumferential wall of the mounting hole 23. A linear elastic ring 6 is arranged between the inner wall of the shoulder 24 and the adjacent bearing 21 to be tested. The detection structure also includes several strain gauges 61 for detecting the axial force data of the bearing 21 to be tested. The strain gauges 61 are mounted on the linear elastic ring 6. The drive structure includes a drive motor 7 and an elastic coupling 71. The output end of the drive motor 7 is coaxially connected to the initial end of the main shaft 13 through the elastic coupling 71.

[0024] Furthermore, it also includes a measurement method comprising the following steps: S1. Install the bearing to be tested and install weights of the corresponding specifications according to the data requirements; S2. Start the drive motor to drive the spindle to rotate clockwise and record the measured readings of the two force sensors and calculate the center distance between the two force sensors and the spindle. Based on the measured readings and center distance, obtain the first total torque using the overall friction torque formula. Switch the drive motor to drive the spindle to rotate counterclockwise and record the measured readings of the two force sensors and calculate the center distance between the two force sensors and the spindle. Based on the measured readings and center distance, obtain the second total torque using the overall friction torque formula. S3. If there is only one bearing to be tested, the first total torque and the second total torque are used to calculate the true friction torque of the bearing to be tested using the first true friction torque formula. If there are two bearings to be tested, the first total torque and the second total torque are used to calculate the true friction torque of the bearing to be tested using the second true friction torque formula.

[0025] Furthermore: the formula for the overall frictional torque in step S2 is as follows: , The two center distance data are respectively and The two measured readings are respectively and ,in and The data represents the preload readings of the force sensor; the calculation result of the first total torque obtained from the overall friction torque formula using two center distance data, two measured readings, and two preload readings when the spindle rotates clockwise is as follows: The calculation result of the first total torque when the spindle rotates counterclockwise, obtained from two center distance data, two measured readings, and two preload readings using the overall friction torque formula, is as follows: .

[0026] Furthermore: if the number of bearings to be tested is two and the spindle rotates clockwise... ; If the number of bearings to be tested is two and the spindle rotates counterclockwise, ; in and The internal torque generated during the installation of the bearing to be tested is denoted as . and These are the actual frictional torque values ​​of the two bearings under test, as stated above. and Two measured readings when the spindle rotates clockwise. and The preload readings of the two force sensors before the spindle rotates clockwise are as follows: and Two measured readings when the spindle rotates counterclockwise. and The data is the preload readings of the two force sensors before the spindle rotates counterclockwise.

[0027] Furthermore: the actual frictional torque of the bearing to be tested is , If there are two bearings to be tested, the actual frictional torque value of a single bearing is expressed as follows: ; If there is only one bearing to be tested, then the actual frictional torque value of the bearing to be tested is expressed as follows:

[0028] Overall operation flow of the rolling bearing friction torque measuring machine that actively eliminates systematic errors: 1. First, assemble and pre-calibrate the equipment: Based on the number of bearings to be tested and whether axial force monitoring is required, select the corresponding bearing housing configuration. If axial force monitoring is required, install a linear elastic ring with strain gauges attached at the bearing housing shoulder. Detachably connect the bearings to be tested between the main shaft and the inner circumferential wall of the bearing housing to complete the assembly of components such as the support bearing, balance beam, and force sensor. Then, by tightening the balance bolts at the beginning of the balance beam, fine-tune the horizontal posture of the balance beam to ensure that the floating structure composed of the bearing housing and the balance beam is in a state of mechanical equilibrium, reducing the initial reading difference of the force sensors on both sides. At the same time, adjust the position of the force sensor through the first and second slide rails to match the sensor range and apply a preload to ensure that the force sensor is in a stable compression state.

[0029] 2. Next, load application and status confirmation are performed: Install weights of the corresponding specifications in the support frame of the balance beam connecting arm, and apply a stable radial load to the bearing to be tested by the gravity of the weights. The swing arm of the support frame can adaptively adjust the position of the weights to avoid load fluctuations. If axial force needs to be applied, tighten the axial loading nut on the main shaft, and monitor the axial force to reach the preset value by strain gauges to simulate the bearing stress state under real working conditions.

[0030] 3. Then, start the forward and reverse rotation test and data acquisition: The drive motor drives the spindle to rotate clockwise through the flexible coupling. Record the preload reading and actual reading of the force sensors on both sides. Combine the distance data between the force sensors and the center of the spindle, calculate the first total torque using the overall friction torque formula. Switch the drive direction to rotate the spindle counterclockwise, repeat the data acquisition process and calculate the second total torque. The forward and reverse rotation test can capture the reverse characteristics of installation errors, providing a data basis for subsequent error elimination.

[0031] 4. Entering the error elimination and true torque calculation stage: Select the corresponding formula according to the number of bearings to be tested. If it is a single bearing, substitute the first total torque and the second total torque into the formula to calculate the true friction torque. If it is two bearings, substitute them into the formula to calculate the true friction torque of a single bearing. This process cancels out the internal torque generated by installation by superimposing forward and reverse rotation data, actively eliminating system errors, so that the measurement results only reflect the true friction characteristics of the bearing to be tested.

[0032] The aforementioned technology can be supplemented with a lubrication system and a temperature monitoring device to achieve friction torque testing under corresponding working conditions, depending on experimental requirements. The lubrication system allows for adjustment of the lubrication medium type, such as oil lubrication or grease lubrication, and the oil supply method, such as oil spraying or oil immersion lubrication, enabling high-precision measurement of rolling bearing friction torque under conditions ranging from dry contact, boundary lubrication, mixed lubrication to fully hydrodynamic lubrication.

[0033] The above design allows for accurate monitoring of radial and axial loads on the bearing. Measurement accuracy can be improved by adjusting the force sensor position, selecting a suitable range, and properly matching the sensor's range. The data monitored by the force sensor only includes the force couple generated by the frictional torque of the bearing itself driving the balance beam to rotate. This force couple can be used to calculate the bearing's frictional torque, eliminating interference from components other than the bearing in the system. Furthermore, by utilizing the measurement results under both forward and reverse rotation conditions, the algorithm proposed in this invention can eliminate frictional torque interference caused by bearing installation errors. Ultimately, highly sensitive rolling bearing frictional torque measurement results are obtained.

[0034] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A rolling bearing friction torque measuring machine that actively eliminates systematic errors, characterized in that: The device includes a platform and a frame mounted on the platform. The frame has a bearing housing and a main shaft. The bearing housing has an inner cavity containing a bearing housing for mounting on the main shaft. At least one bearing to be tested is detachably connected between the outer wall of the main shaft and the inner wall of the bearing housing. The bearing housing has a balancing structure for applying a stable radial load to the bearing to be tested and calibrating the overall balance to reduce manufacturing and counterweight errors. Support bearings for supporting the stable rotation of the main shaft are rotatably connected to both ends of the main shaft and the bearing housing. The bearing housing and the balancing structure combine to form an overall floating structure. The frame has a detection structure for capturing torque and axial force signals to provide data support for calculating the true frictional torque of the bearing to be tested. The platform has a drive structure for driving the main shaft to rotate in both directions.

2. The rolling bearing friction torque measuring machine for actively eliminating systematic errors according to claim 1, characterized in that: Two symmetrical balance beams are arranged on the outer peripheral wall of the bearing housing. Limiting grooves are formed on both side walls of the bearing seat. The two balance beams pass through their respective adjacent limiting grooves. A connecting arm is detachably installed at the center of the balance beam. A weight for applying a downward force to the balance beam is detachably installed at the end of the connecting arm. The end of the balance beam is integrally formed with the bearing housing. The detection structure includes two force sensors, which are respectively located on both sides of the frame. The two balance beams are positioned corresponding to the two force sensors. The starting end of the balance beam is in contact with the detection end of the corresponding force sensor. A first slide rail is formed on the frame corresponding to the two balance beams along the length of the balance beam. A base plate is slidably installed on the first slide rail along the length of the balance beam, and a number of first bolts are detachably connected between the base plate and the first slide rail. A second slide rail is formed on the base plate along the width of the balance beam. A base is slidably installed on the second slide rail, and a number of second bolts are detachably connected between the base and the second slide rail. The base is detachably connected to the force sensor.

3. A rolling bearing friction torque measuring machine for actively eliminating systematic errors according to claim 2, characterized in that: The bottom of the connecting arm is provided with a support frame and the weight is placed in the support frame. The top wall of the support frame is rotatably connected with several swing arms. Each swing arm is provided with a swing groove. The bottom outer peripheral wall of the connecting arm is provided with a fixing pin corresponding to each swing arm position. Each fixing pin is movably set in the corresponding swing groove. The several swing arms are arranged in pairs and are respectively located on both sides of the connecting arm.

4. A rolling bearing friction torque measuring machine for actively eliminating systematic errors according to claim 2, characterized in that: The balance beam has a fine-tuning hole on its initial end wall, and a balance bolt is threaded into the fine-tuning hole to fine-tune the horizontal attitude of the balance beam so that the floating structure composed of the bearing housing and the balance beam is in mechanical equilibrium.

5. A rolling bearing friction torque measuring machine for actively eliminating systematic errors according to claim 1, characterized in that: The bearing housing has a through-hole for accommodating the main shaft and the bearing to be tested. A shoulder is circumferentially provided on the inner peripheral wall of the mounting hole. A linear elastic ring is provided between the inner wall of the shoulder and the adjacent bearing to be tested. The testing structure also includes several strain gauges for detecting the axial force data of the bearing to be tested. The strain gauges are installed on the linear elastic ring.

6. A rolling bearing friction torque measuring machine for actively eliminating systematic errors according to claim 1, characterized in that: The drive structure includes a drive motor and a flexible coupling. The output end of the drive motor is coaxially connected to the beginning end of the main shaft through the flexible coupling.

7. A measurement method for a rolling bearing friction torque measuring machine that actively eliminates systematic errors according to any one of claims 1-6, characterized in that: Includes the following steps: S1. Install the bearing to be tested and install weights of the corresponding specifications according to the data requirements; S2. Start the drive motor to drive the spindle to rotate clockwise and record the measured readings of the two force sensors and calculate the center distance between the two force sensors and the spindle. Based on the measured readings and center distance, obtain the first total torque using the overall friction torque formula. Switch the drive motor to drive the spindle to rotate counterclockwise and record the measured readings of the two force sensors and calculate the center distance between the two force sensors and the spindle. Based on the measured readings and center distance, obtain the second total torque using the overall friction torque formula. S3. If the number of bearings to be tested is one, the first total torque and the second total torque are used to calculate the true friction torque of the bearing to be tested using the first true friction torque formula. If there are two bearings to be tested, the true friction torque of the bearings to be tested can be calculated by using the first total torque and the second total torque formula.

8. The measurement method according to claim 7, characterized in that: The formula for the overall frictional torque in step S2 is: ， The two center distance data are respectively and The two measured readings are respectively and ,in and This is the preload reading data of the force sensor; The calculation result of the first total torque when the spindle rotates clockwise, obtained from two center distance data, two measured readings, and two preload readings using the overall friction torque formula, is as follows: ; The calculation result of the first total torque when the spindle rotates counterclockwise, obtained from two center distance data, two measured readings, and two preload readings using the overall friction torque formula, is as follows: .

9. The measurement method according to claim 8, characterized in that: If the number of bearings to be tested is two and the spindle rotates clockwise, ； If the number of bearings to be tested is two and the spindle rotates counterclockwise, ； in and The internal torque generated during the installation of the bearing to be tested is denoted as . and These are the actual frictional torque values ​​of the two bearings under test, as stated above. and Two measured readings when the spindle rotates clockwise. and The preload readings of the two force sensors before the spindle rotates clockwise are as follows: and Two measured readings when the spindle rotates counterclockwise. and The data is the preload readings of the two force sensors before the spindle rotates counterclockwise.

10. A measurement method according to claim 9, characterized in that: The actual frictional torque of the bearing to be tested is ， If there are two bearings to be tested, the actual frictional torque value of a single bearing is expressed as follows: ； If there is only one bearing to be tested, then the actual frictional torque value of the bearing to be tested is expressed as follows: 。

Images