Device and method for measuring high-speed transient friction torque of rolling bearing

Abstract

The invention relates to the technical field of rolling bearing tribological performance measurement, in particular to a rolling bearing high-speed transient friction torque measuring device and method. The measuring device comprises a rack, and two bearings to be measured are installed on the rack. The tested bearings are connected through a transmission shaft, one end of the transmission shaft is connected with a servo power system, and a speed sensor is arranged on the transmission shaft; after a shaft system composed of the two tested bearings is accelerated to a certain speed, a clutch is disconnected, the shaft system is in an angular velocity free attenuation state, then an angular velocity change curve in the process is recorded through a speed sensor, and the transient friction torque of the tested bearings can be obtained. The problem that torque measurement cannot be carried out in an unbalanced state by a traditional measurement method is solved. According to the invention, only two tested bearings are arranged, so that errors caused by extra friction of the bearings of the torque sensor are avoided; and the precision of the adopted speed sensor is far higher than that of a torque sensor, so that the friction torque measurement precision is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of rolling bearing tribological performance measurement, and in particular to a rolling bearing high-speed transient friction torque measurement device and a measurement method. Background Art

[0002] Friction torque is a key indicator for evaluating the friction performance of rolling bearings. It directly affects the temperature rise, energy consumption, precision and service life of the bearings, and is crucial to ensuring the long-term stable operation of precision mechanical equipment such as satellite momentum wheels and inertial gyroscopes. At present, the industry generally uses friction torque to characterize the comprehensive friction performance of bearings, and uses various types of friction torque measurement equipment to measure them. However, most existing friction torque measurement equipment uses the principle of balanced torque to measure from a mechanical level, and can only measure under constant speed and steady-state conditions. Faced with the complex and changeable working conditions of rolling bearings in high-end precision equipment such as satellite attitude adjustment mechanisms and high-precision inertial gyroscopes, traditional steady-state measurement equipment may lead to problems such as failure to capture transient friction response, lack of dynamic stability assessment and delayed failure warning due to insufficient resolution.

[0003] Existing friction torque measurement equipment all measures bearing friction torque from a mechanical perspective, with the torque sensor as its core component. Traditional measurement equipment requires ensuring that the friction torque of the bearing being measured is balanced with the torque of the torque sensor, but achieving absolute equilibrium is challenging. This difficulty in precisely controlling equilibrium is a major contributor to the high discreteness of errors in traditional friction torque measurement equipment. Furthermore, the torque sensors in traditional equipment inherently incorporate rolling bearings, and the friction of the torque sensor bearings inevitably contributes to the friction of the torque sensor's bearings in the friction torque measurement of the bearing being measured, leading to significant measurement errors. Summary of the Invention

[0004] The object of the present invention is to provide a rolling bearing high-speed transient friction torque measuring device and method which can measure the transient friction torque under the working conditions of continuous speed and variable load.

[0005] Based on the above purpose, the present invention adopts the following technical solutions:

[0006] A device for measuring the high-speed transient friction torque of a rolling bearing includes a frame and is characterized in that: mounting structures are symmetrically provided at both ends of the frame, and a pair of bearings to be measured are installed in the mounting structures; the pair of bearings to be measured are connected by a transmission shaft, one end of the transmission shaft exceeds the bearings to be measured and is connected to a servo power system through the transmission shaft; a speed sensor is provided on the transmission shaft, and the speed sensor is connected to a host control system.

[0007] Preferably, the speed sensor includes an encoder, which records the angular position and angular velocity of the transmission shaft; a reading head is provided in conjunction with the encoder, which reads the speed information in real time; and the reading head is connected to the upper control system via a data cable.

[0008] Preferably, the mounting structure includes a pair of bearing seats, which are respectively arranged at the left and right ends of the frame; a pair of bearing seats are coaxially provided with mounting holes, and the tested bearing is fixedly mounted in the mounting holes of the bearing seats through a transition sleeve.

[0009] Preferably, the transmission shaft includes a main shaft, with a left journal and a right journal connected to both ends of the main shaft, and the left journal and the right journal are respectively connected to two bearings to be tested; a counterweight flywheel is coaxially arranged in the middle of the main shaft, and a speed sensor is arranged on the main shaft.

[0010] Preferably, one end of the transmission shaft is coaxially connected to the power output shaft through a clutch, and the power output shaft is connected to the servo power system.

[0011] A method for measuring the high-speed transient friction torque of a rolling bearing comprises the following steps:

[0012] S1. Start the transmission shaft: Start the servo power system, so that the power input shaft drives the transmission shaft to rotate to a predetermined speed through the clutch, and keep it running stably for a period of time to make the tested bearing in a dynamic balance state;

[0013] S2, disconnect the clutch: disconnect the clutch to disconnect the transmission shaft from the power input shaft, and the transmission shaft enters a free decay state;

[0014] S3, measuring the rotational speed: after the clutch is disconnected in step S2, continuously measuring the rotational speed of the transmission shaft to obtain a model of the measured bearing rotational speed with respect to time;

[0015] S4. Calculate the friction torque of the measured shaft system: Based on the speed-time model of the two measured bearings obtained in step S3, obtain the equivalent friction torque of the entire measured shaft system;

[0016] S5. Calculate the friction torque of each tested bearing separately: introduce a standard bearing, and repeat steps S1-S4 using the standard bearing in combination with the two tested bearings to obtain the friction torque of each tested bearing.

[0017] Preferably, the specific process of calculating the friction torque of the measured shaft system in step S4 includes:

[0018] According to the kinematic analysis of rolling bearings, the relationship between the revolution speed of the rolling element and the angular velocity of the inner ring is:

[0019] ω m =k1·ω i (1)

[0020] The relationship between the rolling element rotation speed and the inner ring angular velocity is:

[0021]

[0022] Among them, D b is the rolling element diameter; D m is the bearing pitch diameter; the calculation formulas for coefficients k1 and k2 are:

[0023]

[0024] Where α is the rolling element contact angle;

[0025] The angular velocity of the moving parts is uniformly converted into the angular velocity of the inner ring, and the total kinetic energy of the measured shaft system is:

[0026]

[0027] Total moment of inertia of the shaft system J t It is composed of rotating parts:

[0028]

[0029] Among them, J s ,J i ,J c ,J r ,J z are the moments of inertia of the main shaft, bearing inner ring, cage, and rolling element revolution and rotation respectively; J t is the total moment of inertia of the shaft system; z is the number of rolling elements in the bearing; k1 and k2 are the coefficients of relationship between the orbital speed and rotational speed of the rolling elements and the speed of the inner ring respectively;

[0030] The friction power of the bearing under test can be obtained by differentiating the kinetic energy of the shaft system:

[0031]

[0032] By obtaining the relationship between the friction power and angular velocity of the tested bearing, the equivalent friction torque of the two tested bearings is:

[0033] M A +M B =P AB / ω (7)

[0034] Among them, M A 、M B are the friction torques of the two tested bearings respectively.

[0035] Preferably, the specific process of calculating the friction torque of each tested bearing in step S5 includes:

[0036] Introduce a standard bearing and combine it with the two tested bearings to form a shaft system. Repeat steps S1-S4 to obtain the friction torque of the standard bearing after the shaft system is formed with the two tested bearings. The combined equation (7) is:

[0037]

[0038] Among them, M C is the friction torque of the standard bearing, M AB is the friction torque of the shaft system composed of two bearings under test, M AC and M BC is the sum of the friction moments of the shaft system composed of the standard bearing and the two tested bearings; solving formula (8) can obtain the friction moments of the two tested bearings respectively.

[0039] An electronic device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, any step of any of the above-mentioned methods for measuring high-speed transient friction torque of a rolling bearing is implemented.

[0040] The beneficial effects of the present invention are:

[0041] The present invention proposes to use a speed sensor to replace the traditional torque sensor to measure the friction torque of the rolling bearing from the perspective of kinetic energy (angular velocity) changes; by real-time monitoring of the kinetic energy and angular velocity changes of the bearing, the kinetic energy is differentiated to obtain the friction power of the measured bearing, and the friction torque of the measured bearing is obtained based on the relationship between friction power, angular velocity and friction torque (M=P / ω), which solves the problem that traditional torque sensors cannot measure the bearing friction torque in an unbalanced state.

[0042] The measuring device used in the present invention uses two measured bearings to form a shaft system for measurement, which can effectively avoid the errors caused by the bearings of the torque sensor in the traditional method being introduced into the shaft system as additional friction; at the same time, since the accuracy of the speed sensor is usually much better than that of the torque sensor, the present invention can achieve a significant improvement in the measurement accuracy of the friction torque of the rolling bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0044] Figure 2 Schematic diagram of the journal used in Example 1 of the present invention;

[0045] Figure 3 Schematic diagram of the journal used in Example 2 of the present invention;

[0046] Figure 4 Schematic diagram of the journal used in Example 3 of the present invention;

[0047] Figure 5 This is a flowchart of Example 4 of the present invention.

[0048] In the figure: left bearing seat 1; left transition sleeve 2; left measured bearing 3; left shaft neck 4; main shaft 5; counterweight flywheel 6; encoder 7; reading head 8; right shaft diameter 9; right measured bearing 10; right transition sleeve 11; right bearing seat 12; upper control system 13; data transmission cable 14; clutch driven end 15; clutch active end 16; power input shaft 17; frame 18. DETAILED DESCRIPTION

[0049] Example 1

[0050] The following is a further explanation of the present invention with reference to specific embodiments. Figure 1 As shown, this embodiment is a high-speed transient friction torque measuring device for rolling bearings, including a frame 18, on which a mounting structure is provided, the mounting structure including a pair of bearing seats, namely a left bearing seat 1 and a right bearing seat 12; both bearing seats are provided with mounting through holes, and the two mounting through holes are coaxially arranged; in the mounting through holes, a left measured bearing 3 and a right measured bearing 10 are connected through a transition sleeve; in this embodiment, the measuring device adopts a horizontal structure, and can also adopt a vertical layout as needed; in this embodiment, the measured bearing is a deep groove ball bearing, and this embodiment can also be applied to other types of rolling bearings such as cylindrical roller bearings and angular contact ball bearings.

[0051] The outer ring of the left tested bearing 3 cooperates with the left transition sleeve 2, and the outer ring of the right tested bearing 10 cooperates with the right transition sleeve 11; the inner ring of the left tested bearing 3 is cooperated with the left shaft neck 4, and the inner ring of the right tested bearing 10 is cooperated with the right shaft neck 9; the left shaft neck 4 and the right shaft neck 9 are symmetrically fixedly connected to the two ends of a main shaft 5, and the main shaft 5 and the two shaft necks are combined to form a transmission shaft structure.

[0052] A counterweight flywheel 6 is provided in the middle of the main shaft 5. The counterweight flywheel 6 can improve the inertial energy storage capacity of the shaft system and lengthen the angular velocity attenuation process of the shaft system as much as possible to improve the resolution of the main shaft speed measurement. It can also apply a load to the bearing to be measured. By replacing the counterweight flywheel 6 with different masses, the bearing load of the bearing to be measured can be changed; a speed sensor is provided on the main shaft 6, including an encoder 7 and a reading head 8; the encoder 7 is used to record the angular position and angular velocity information of the main shaft 6, and the reading head 8 can read the speed information of the main shaft in real time, and transmit the information to the upper control system 13 for data processing through the data cable 14; in this embodiment, the speed sensor can also adopt a laser speed sensor, and a high-precision grating is set on the main shaft to collect higher-precision speed information.

[0053] In this embodiment, the right end of the right shaft diameter is set as an extension part and is connected to a power input shaft 17 through a clutch; the power input shaft 17 is connected to the servo power system and can input external power into the shaft system; the clutch includes a clutch driven end 15 connected to the right shaft diameter 9 and a clutch active end 16 connected to the power input shaft 17. The clutch driven end 15 and the clutch active end 16 can be remotely unlocked by the upper control system 13.

[0054] The diameters of the left journal 2 and the right shaft diameter 9 can be determined according to the actual size of the bearing being measured. In this embodiment, Figure 2 As shown, the diameters of the left journal 2 and the right journal 9 are both 30 mm.

[0055] Example 2

[0056] The difference between this embodiment and embodiment 1 is that Figure 3 As shown, in this embodiment, the diameters of the left journal 2 and the right journal 9 are both 40 mm.

[0057] Example 3

[0058] The difference between this embodiment and embodiment 1 is that Figure 3 As shown, in this embodiment, the diameters of the left journal 2 and the right journal 9 are both 50 mm.

[0059] Example 4

[0060] like Figure 5 As shown, this embodiment is a method for measuring the high-speed transient friction torque of a rolling bearing using the measuring device in Example 1, comprising the following steps:

[0061] S1. Start the transmission shaft: Start the servo power system so that the power input shaft drives the transmission shaft to rotate to a predetermined speed through the clutch, and keep it running stably for a period of time to put the tested bearing in a dynamic equilibrium state.

[0062] S2. Disconnect the clutch: Disconnect the clutch to disconnect the drive shaft from the power input shaft, and the drive shaft enters a free decay state. At this time, the shaft system enters a free decay state of angular velocity only under the action of its own friction force. Since the measured shaft system is disconnected from the outside world, the friction torque of the measured bearing (excluding air resistance) can be purely measured.

[0063] S3. Measure the rotational speed: After the clutch is disconnected in step S2, the rotational speed of the drive shaft is continuously measured to obtain a time-dependent model of the measured bearing rotational speed. During the free decay of the angular velocity of the measured bearing, the angular position and angular velocity changes of the spindle are monitored in real time using a high-precision encoder on the spindle. Since the spindle and the inner ring of the bearing are rigidly connected, the angular velocity of the inner ring of the bearing is also obtained simultaneously.

[0064] S4. Calculate the friction torque of the measured shaft system: Based on the speed-time model of the two measured bearings obtained in step S3, obtain the equivalent friction torque of the entire measured shaft system.

[0065] For the entire shaft system, the total kinetic energy of the shaft system includes not only the main shaft but also the kinetic energy of the moving parts of the rolling bearing. The angular velocity of the inner ring is obtained by the speed sensor, and the angular velocity of the cage is also obtained by the speed sensor. According to the kinematic analysis of the rolling bearing, the relationship between the orbital velocity of the rolling element and the angular velocity of the inner ring is:

[0066] ω m =k1·ω i (1)

[0067] The relationship between the rolling element rotation speed and the inner ring angular velocity is:

[0068]

[0069] Among them, D b is the rolling element diameter; D m is the bearing pitch diameter; the calculation formulas for coefficients k1 and k2 are:

[0070]

[0071] Where α is the rolling element contact angle;

[0072] The angular velocity of the moving parts is uniformly converted into the angular velocity of the inner ring, and the total kinetic energy of the measured shaft system is:

[0073]

[0074] Total moment of inertia of the shaft system J t It is composed of rotating parts:

[0075]

[0076] Among them, J s ,J i ,J c ,J r ,J z are the moments of inertia of the main shaft, bearing inner ring, cage, and rolling element revolution and rotation respectively; J t is the total moment of inertia of the shaft system; z is the number of rolling elements in the bearing; k1 and k2 are the coefficients of relationship between the orbital speed and rotational speed of the rolling elements and the speed of the inner ring respectively;

[0077] The friction power of the bearing under test can be obtained by differentiating the kinetic energy of the shaft system:

[0078]

[0079] By obtaining the relationship between the friction power and angular velocity of the tested bearing, the equivalent friction torque of the two tested bearings is:

[0080] M A +M B =P AB / ω (7)

[0081] Among them, M A 、M B are the friction torques of the two tested bearings respectively.

[0082] S5. Calculate the friction torque of each tested bearing separately: introduce a standard bearing, and repeat steps S1-S4 with the standard bearing and the two tested bearings to obtain the friction torque of the shaft system formed by the standard bearing and the two tested bearings. Combine equation (7) to obtain:

[0083]

[0084] Among them, M C is the friction torque of the standard bearing, M AB is the friction torque of the shaft system composed of two bearings under test, M AC and M BC are the friction torques and of the shaft system consisting of the standard bearing and the two tested bearings.

[0085] Solving equation (8) can obtain the friction torque of the two measured bearings respectively; further, this measuring device can be extended to measure N bearings, and a set of N linear equations can be constructed to obtain the friction torque of each bearing. The friction torque of each measured bearing can be sorted to accurately evaluate the friction performance of the bearing.

[0086] The above description is merely a further explanation of the present invention in conjunction with specific embodiments. All descriptions do not limit the scope of protection of the present invention. Any changes or replacements that can be easily thought of by any technician in this field within the technical scope disclosed by the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A rolling bearing high-speed transient friction torque measurement device, comprising a frame, characterized in that: Mounting structures are symmetrically provided at both ends of the frame, and a pair of bearings to be tested are installed in the mounting structures; the pair of bearings to be tested are connected by a transmission shaft, one end of the transmission shaft exceeds the bearings to be tested and is connected to a servo power system through the transmission shaft; a speed sensor is provided on the transmission shaft, and the speed sensor is connected to a host control system.

2. The rolling bearing high-speed transient friction torque measuring device according to claim 1, characterized in that: The speed sensor includes an encoder that records the angular position and angular velocity of the transmission shaft; a reading head is provided in conjunction with the encoder, and the reading head reads the speed information in real time; the reading head is connected to the upper control system via a data cable.

3. The rolling bearing high-speed transient friction torque measuring device according to claim 2, characterized in that: The mounting structure includes a pair of bearing seats, which are respectively arranged at the left and right ends of the frame; a pair of bearing seats are coaxially provided with mounting holes, and the tested bearing is fixedly mounted in the mounting holes of the bearing seats through a transition sleeve.

4. The rolling bearing high-speed transient friction torque measuring device according to claim 3, characterized in that: The transmission shaft includes a main shaft, with a left journal and a right journal connected to both ends of the main shaft respectively, and the left journal and the right journal are respectively connected to the two bearings to be tested; a counterweight flywheel is coaxially arranged in the middle of the main shaft, and the speed sensor is arranged on the main shaft.

5. The rolling bearing high-speed transient friction torque measuring device according to claim 4, characterized in that: One end of the transmission shaft is coaxially connected to a power output shaft through a clutch, and the power output shaft is connected to the servo power system.

6. A method for measuring the high-speed transient friction torque of a rolling bearing according to the device of any one of claims 1 to 5, comprising the following steps: S1. Start the transmission shaft: Start the servo power system, so that the power input shaft drives the transmission shaft to rotate to a predetermined speed through the clutch, and keep it running stably for a period of time to make the tested bearing in a dynamic balance state; S2, disconnect the clutch: disconnect the clutch to disconnect the transmission shaft from the power input shaft, and the transmission shaft enters a free decay state; S3, measuring the rotational speed: after the clutch is disconnected in step S2, continuously measuring the rotational speed of the transmission shaft to obtain a model of the measured bearing rotational speed with respect to time; S4. Calculate the friction torque of the measured shaft system: Based on the speed-time model of the two measured bearings obtained in step S3, obtain the equivalent friction torque of the entire measured shaft system; S5. Calculate the friction torque of each tested bearing separately: introduce a standard bearing, and repeat steps S1-S4 using the standard bearing in combination with the two tested bearings to obtain the friction torque of each tested bearing.

7. The method for measuring high-speed transient friction torque of a rolling bearing according to claim 6, characterized in that: The specific process of calculating the friction torque of the measured shaft system in step S4 includes: According to the kinematic analysis of rolling bearings, the relationship between the revolution speed of the rolling element and the angular velocity of the inner ring is: oh m =k1·ω i (1) The relationship between the rolling element rotation speed and the inner ring angular velocity is: Among them, D b is the rolling element diameter; D m is the bearing pitch diameter; the calculation formulas for coefficients k1 and k2 are: Where α is the rolling element contact angle; The angular velocity of the moving parts is uniformly converted into the angular velocity of the inner ring, and the total kinetic energy of the measured shaft system is: Total moment of inertia of the shaft system J t It is composed of rotating parts: Among them, J s ,J i ,J c ,J r ,J z are the moments of inertia of the main shaft, bearing inner ring, cage, and rolling element revolution and rotation respectively; J t is the total moment of inertia of the shaft system; z is the number of rolling elements in the bearing; k1 and k2 are the coefficients of relationship between the orbital speed and rotational speed of the rolling elements and the speed of the inner ring respectively; The friction power of the bearing under test can be obtained by differentiating the kinetic energy of the shaft system: Based on the relationship between the friction power and angular velocity of the tested bearings, the equivalent friction torque of the two tested bearings is: M A +M B =P AB / ω (7) Among them, M A 、M B are the friction torques of the two tested bearings respectively.

8. The method for measuring high-speed transient friction torque of a rolling bearing according to claim 7, characterized in that: The specific process of calculating the friction torque of each tested bearing in step S5 includes: Introduce a standard bearing and combine it with the two tested bearings to form a shaft system. Repeat steps S1-S4 to obtain the friction torque of the standard bearing after the shaft system is formed with the two tested bearings. The combined equation (7) is: Among them, M C is the friction torque of the standard bearing, M AB is the friction torque of the shaft system composed of two bearings under test, M AC and M BC is the sum of the friction moments of the shaft system composed of the standard bearing and the two tested bearings; solving formula (8) can obtain the friction moments of the two tested bearings respectively.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, any step of the method for measuring the high-speed transient friction torque of a rolling bearing as described in any one of claims 6 to 8 is implemented.

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