A measuring device for the friction coefficient of liquid metal sliding bearings

Abstract

The application relates to the technical field of nondestructive measuring instruments, and discloses a kind of measuring equipment of liquid metal sliding bearing friction coefficient, it includes workbench, main shaft, displacement sensor, temperature sensor, pressure sensor and processor, wherein: workbench is fixedly installed at predetermined position;Main shaft is horizontally arranged above workbench by mounting bracket, and is rotationally matched with mounting bracket in the direction of its own axis, is rotated by rotating drive unit, and main shaft is used for coaxially installing bearing to be measured;Displacement sensor is fixedly installed at predetermined position by displacement support;Temperature sensor is installed at the position of bearing to be measured;Pressure sensor is close to or away from the outer ring wall of bearing to be measured by lifting drive unit;Displacement sensor, temperature sensor and pressure sensor are connected with processor by cable.The application has the effect of facilitating the measurement of liquid metal sliding bearing friction coefficient.

Description

Technical Field

[0001] This application relates to the field of nondestructive testing instruments, and in particular to a device for measuring the friction coefficient of a liquid metal sliding bearing. Background Technology

[0002] Sliding bearings are key basic components in rotating machinery, and their performance directly affects the operating efficiency and lifespan of the equipment. Liquid metals (such as gallium-based and bismuth-based alloys) are gradually becoming the ideal choice for lubrication media under extreme operating conditions due to their excellent thermal conductivity and high temperature resistance.

[0003] However, measuring the friction coefficient of liquid metal sliding bearings under high-speed and heavy-load conditions presents challenges, as traditional methods struggle to obtain stable data in enclosed, high-temperature environments.

[0004] Therefore, there is an urgent need for a device that can accurately measure the coefficient of friction online. Utility Model Content

[0005] To facilitate the measurement of the friction coefficient of liquid metal sliding bearings, this application provides a measuring device for the friction coefficient of liquid metal sliding bearings.

[0006] The device for measuring the friction coefficient of a liquid metal sliding bearing provided in this application adopts the following technical solution: A device for measuring the friction coefficient of a liquid metal sliding bearing includes a worktable, a spindle, a displacement sensor, a temperature sensor, a pressure sensor, and a processor, wherein: The workbench is fixedly installed at a predetermined position; The spindle is horizontally mounted above the worktable via a mounting bracket and rotates around its own axis in conjunction with the mounting bracket. It rotates via a rotary drive unit and is used to coaxially mount the bearing to be tested. The displacement sensor is fixedly installed at a predetermined position by a displacement bracket; The temperature sensor is installed at the location of the bearing to be tested; The pressure sensor moves closer to or further away from the outer ring wall of the bearing under test via a lifting drive unit. The displacement sensor, temperature sensor, and pressure sensor are all connected to the processor via cables.

[0007] Optionally, the rotary drive unit includes a mounting base and a motor, wherein: The placement seat is fixedly installed on the workbench, and the motor shaft of the motor is connected to the main shaft via a transmission connection.

[0008] Optionally, the motor shaft of the motor is fixedly connected to the main shaft via a coupling.

[0009] Optionally, the displacement sensor is provided in two sets, and each set of displacement sensors is circumferentially distributed around the axis of the main shaft.

[0010] Optionally, the lifting drive unit includes a support frame, a rotating rod, and a telescopic rod, wherein: The support frame is fixedly installed on the workbench; The rotating rod is mounted on the support frame and rotates around the horizontal line in coordination with the support frame; The bottom end of the telescopic rod is fixedly mounted on the workbench, the top end of the telescopic rod is rotatably hinged to one end of the rotating rod, and the pressure sensor is rotatably hinged to the other end of the rotating rod.

[0011] In summary, this application includes at least one of the following beneficial technical effects: 1. By arranging two sets of laser displacement sensors evenly around the circumference and converging at the same point on the spindle axis, the radial displacement of the spindle and bearing outer ring can be monitored synchronously in all directions without blind spots. Combined with data fusion algorithm, the complete radial motion trajectory can be reconstructed, which significantly improves the accuracy and reliability of displacement measurement and effectively eliminates the blind spots and random errors caused by single-direction measurement. 2. The use of an electric cylinder to drive the rotating rod to achieve the arc lifting trajectory of the pressure sensor makes the application and removal of radial loads smooth, controllable and repeatable, ensuring the accuracy of the load application position and force, and improving the stability of the friction coefficient test process and the consistency of experimental data. 3. By synchronously collecting multidimensional data on displacement, temperature, and pressure under the same time reference and submitting them to a computer for comprehensive analysis, not only can the friction coefficient be calculated in real time, but the state of lubrication film formation and bearing operation stability can also be judged by radial displacement changes. This enables early identification of abnormal wear or instability, significantly enhancing the comprehensiveness and early warning capability of the equipment for evaluating bearing service performance. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0013] Explanation of reference numerals in the attached figures: 1. Motor; 2. Coupling; 3. Fixed bearing; 4. Displacement sensor; 5. Temperature sensor; 6. Pressure sensor; 7. Rotating rod; 8. Placement seat; 9. Mounting bracket; 10. Displacement bracket; 11. Bearing to be tested; 12. Torque rod bracket; 13. Spindle; 14. Worktable; 15. Telescopic rod. Detailed Implementation

[0014] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0015] This application discloses a device for measuring the friction coefficient of a liquid metal sliding bearing.

[0016] A device for measuring the friction coefficient of a liquid metal sliding bearing includes a worktable 14, a spindle 13, a displacement sensor 4, a temperature sensor 5, a pressure sensor 6, and a processor. The worktable 14 is securely mounted in a predetermined position. The spindle 13 is horizontally positioned above the worktable 14 via a mounting bracket 9. A fixed bearing 3 is mounted on the mounting bracket 9, and the spindle 13 and the fixed bearing 3 on the mounting bracket 9 form a rotational engagement, allowing the spindle 13 to rotate around its own axis under the drive of a rotary drive unit. This spindle 13 is used to coaxially mount the sliding bearing under test. The displacement sensor 4 is fixed in a predetermined position via a displacement bracket 10 and is used to monitor the radial displacement changes of the bearing under test 11 and the spindle 13 in real time. The temperature sensor 5 is directly arranged near the bearing under test 11 to monitor its temperature. The pressure sensor 6 is vertically moved via a lifting drive unit, allowing it to approach or move away from the outer ring wall of the bearing under test 11. The top of the workbench 14 is also equipped with a torque rod 12 to prevent the outer ring of the bearing 11 under test from moving. The displacement sensor 4, temperature sensor 5 and pressure sensor 6 are all connected to the processor via cables, and the processor is connected to the computer via cables to transmit the collected data to the computer for analysis and control.

[0017] The friction coefficient is calculated by simultaneously measuring radial load, frictional resistance, temperature, and key radial motion conditions under simulated operating conditions. Radial displacement data monitored by displacement sensor 4 is a crucial indicator for evaluating bearing operational stability, rotational accuracy, and the dynamic characteristics of the lubricating film. Combined with temperature and pressure data, it provides a more comprehensive basis for accurately calculating the friction coefficient and can be used to identify whether the bearing is in an abnormal wear or unstable state.

[0018] After the bearing 11 under test is installed, the position of the pressure sensor 6 is adjusted via the lifting drive unit to apply a radial load. Simultaneously, the initial radial position of the entire system is monitored using the displacement sensor 4, serving as a reference for subsequent data changes. As the spindle 13 drives the bearing to rotate, the displacement sensor 4 continuously captures minute radial displacement changes in both the spindle 13 and the bearing. The pressure sensor 6 monitors load changes, and the temperature sensor 5 monitors temperature rise.

[0019] The computer comprehensively processes multi-dimensional data such as radial displacement, temperature, and pressure. Radial displacement data is used to determine changes in bearing clearance, the establishment of the lubricating film, and the smoothness of operation.

[0020] The processor employs a multi-channel synchronous data acquisition card to ensure that all displacement signals are acquired synchronously, avoiding measurement errors caused by time asynchrony. Data analysis is performed using a control computer running a custom data processing program.

[0021] The rotary drive unit consists of a mounting base 8 and a motor 1. The mounting base 8 is fixedly mounted on the worktable 14, and the motor 1 is fixedly mounted on the mounting base 8. The motor shaft of the motor 1 is directly connected to the spindle 13 through components such as a coupling 2, thereby accurately and reliably transmitting the rotational power of the motor 1 to the spindle 13.

[0022] The rotational motion is directly transmitted to the main shaft 13 via the motor shaft 1 through the transmission connection, thereby driving the bearing under test 11 mounted on the main shaft 13 to rotate precisely, simulating the motion state in actual working conditions, so that the bearing under test 11 can reach and maintain the set test speed in the liquid metal medium.

[0023] Two sets of displacement sensors 4 are provided, both arranged circumferentially around the axis of the main shaft 13. One set is responsible for monitoring the radial displacement of the main shaft 13 itself, and the other set is responsible for monitoring the radial displacement of the bearing 11 under test. Each set of displacement sensors 4 contains multiple probes, which are evenly distributed circumferentially along the axis of the main shaft 13. In this embodiment, each set specifically has eight displacement sensors 4, which are laser displacement sensors 4. The laser beam measurement directions of the multiple laser displacement sensors 4 in each set are precisely calibrated to ensure that they intersect at the same target point on the axis of the main shaft 13.

[0024] During equipment operation, two sensor arrays work synchronously. The sensor array monitoring the displacement of the spindle 13 captures the spindle 13's rotational accuracy and vibration in real time; the sensor array monitoring the bearing displacement simultaneously captures the dynamic response of the bearing's outer ring under load and lubrication conditions. Data from eight directions is transmitted to the processor simultaneously. Through data fusion algorithms, the precise radial motion trajectory and eccentricity of the spindle 13 or bearing within the measurement section can be reconstructed, rather than just the displacement in a single direction. This eliminates measurement blind spots, achieving panoramic, blind-spot-free monitoring of the radial motion of the rotating body, effectively averaging out random errors, and identifying true eccentric motion and instantaneous vibrations, resulting in extremely high reliability of the measured displacement data.

[0025] The lifting drive unit includes a support frame, a rotating rod 7, and a telescopic rod 15. The support frame is fixedly mounted on the worktable 14. The rotating rod 7 is mounted on the support frame and rotates around a horizontal line in coordination with the support frame. The bottom end of the telescopic rod 15 is fixedly mounted on the worktable 14, and the top end of the telescopic rod 15 is rotatably hinged to one end of the rotating rod 7. The pressure sensor 6 is rotatably hinged to the other end of the rotating rod 7. In this embodiment, the pressure sensor 6 is a thin-film weighing sensor.

[0026] The lifting drive unit consists of a support frame, a rotating rod 7, and a telescopic rod 15. The support frame is fixedly mounted on the worktable 14, serving as the static base of the entire unit. The rotating rod 7 is mounted on the support frame and can rotate around a horizontal axis. The bottom end of the telescopic rod 15 is fixed to the worktable 14, and its top end is connected to one end of the rotating rod 7 via a rotating hinge. The pressure sensor 6 is mounted on the other end of the rotating rod 7 away from the telescopic rod 15 via another rotating hinge. In this embodiment, the telescopic rod 15 is specifically an electric cylinder, which is connected to a computer via a cable to receive control commands.

[0027] By utilizing the linear reciprocating motion of the telescopic rod 15, which is converted into the angular displacement of the rotating rod 7 through the hinge, the pressure sensor 6, fixed at the other end of the rotating rod 7, is ultimately driven to perform an approximately circular arc lifting trajectory with the pivot point of the rotating rod 7 as the center, thereby achieving precise control over its position.

[0028] Initially, the electric cylinder moves upward at a relatively high speed, bringing the pressure sensor 6 close to the surface of the bearing 11 under test. Once the pressure sensor 6 contacts the surface of the bearing 11, its reading begins to rise. When the pressure exceeds a very small threshold (currently set to 50N), it is determined that contact has been achieved, and the system switches to pressure control mode, with the electric cylinder moving at a low speed for precise control. The pressure value of the pressure sensor 6 is compared with the set value in real time to ensure that the pressure on the bearing 11 under test remains within the error range of the set pressure value.

[0029] When the computer issues a command, the electric cylinder activates, and its push rod extends or retracts. This linear motion pushes or pulls one end of the rotating rod 7 via a rotating hinge at the bottom, forcing the rotating rod 7 to rotate around its mating point with the support frame. The rotation of the rotating rod 7 is directly converted into the lifting or pressing action of its other end, thereby enabling the pressure sensor 6 to smoothly approach to contact and load the outer ring of the bearing, or smoothly move away to relieve the load.

[0030] Through the above operations, the oil film thickness, oil film pressure, and rotational speed can be obtained. The eccentricity can be calculated from the oil film thickness and the radial clearance; the oil film bearing capacity can be obtained by integrating the oil film pressure distribution; and the rotational speed can be converted into relative sliding speed. Combining the eccentricity, relative sliding speed, and known data such as the radial clearance and dynamic viscosity, the total friction force can be calculated. Dividing the total friction force by the oil film bearing capacity yields the oil film's coefficient of friction.

[0031] Temperature sensor 5 is a digital infrared temperature sensor. When the bearing under test 11 is running at a speed of 10,000 rpm, the radial load applied by the pressure sensor 6 through the lever structure will cause the liquid metal oil film inside the bearing under test 11 to generate shear friction. The heat generated by the friction will cause the temperature of the outer ring of the bearing to gradually rise.

[0032] Temperature sensor 5 transmits the collected temperature data to the processor in real time, and performs synchronous analysis with the oil film thickness data and rotational speed parameters calculated by displacement sensor 4. By establishing a correlation model between the rate of temperature change, oil film thickness, and frictional torque, the load-bearing capacity and lubrication status of the oil film can be reflected more intuitively.

[0033] The implementation principle of the device for measuring the friction coefficient of a liquid metal sliding bearing in this application embodiment is as follows: First, the sliding bearing to be tested is coaxially installed on the main shaft 13 driven by the motor 1 through the coupling 2. The computer commands the electric cylinder to extend and retract, and the pressure sensor 6 is precisely sent to the outer ring of the bearing to apply a radial load and record the load value through the angular displacement of the rotating rod 7. At the same time, two sets of eight laser displacement sensors 4 are evenly arranged around the axis of the main shaft 13 in the circumferential direction, respectively capturing the small displacements of the main shaft 13 and the outer ring of the bearing in eight radial directions in real time. The temperature sensor 5 monitors the bearing temperature rise synchronously. All displacement, pressure and temperature signals are sent to the computer through the processor. The computer uses the initial radial position as a reference, integrates multi-dimensional data to reconstruct the complete radial motion trajectory and eccentricity of the main shaft 13 and the bearing, and judges the establishment of lubricating film, gap change and running stability by combining load and temperature rise changes. Based on this, the computer comprehensively calculates and outputs the real-time friction coefficient of the bearing in the liquid metal medium, and at the same time identifies abnormal wear or instability.

[0034] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A measuring device for the friction coefficient of a liquid metal sliding bearing, characterized in that: It includes a worktable, spindle, displacement sensor, temperature sensor, pressure sensor, and processor, among which: The workbench is fixedly installed at a predetermined position; The spindle is horizontally mounted above the worktable via a mounting bracket and rotates around its own axis in conjunction with the mounting bracket. It rotates via a rotary drive unit and is used to coaxially mount the bearing to be tested. The displacement sensor is fixedly installed at a predetermined position by a displacement bracket; The temperature sensor is installed at the location of the bearing to be tested; The pressure sensor moves closer to or further away from the outer ring wall of the bearing under test via a lifting drive unit. The displacement sensor, temperature sensor, and pressure sensor are all connected to the processor via cables.

2. The measuring device for the friction coefficient of a liquid metal sliding bearing according to claim 1, characterized in that: The rotary drive unit includes a mounting base and a motor, wherein: The placement seat is fixedly installed on the workbench, and the motor shaft of the motor is connected to the main shaft via a transmission connection.

3. The measuring device for the friction coefficient of a liquid metal sliding bearing according to claim 2, characterized in that: The motor shaft of the motor is fixedly connected to the main shaft via a coupling.

4. The measuring device for the friction coefficient of a liquid metal sliding bearing according to claim 1, characterized in that: The displacement sensor is provided in two sets, and each set of displacement sensors is circumferentially distributed around the axis of the main shaft.

5. The measuring device for the friction coefficient of a liquid metal sliding bearing according to claim 1, characterized in that: The lifting drive unit includes a support frame, a rotating rod, and a telescopic rod, wherein: The support frame is fixedly installed on the workbench; The rotating rod is mounted on the support frame and rotates around the horizontal line in coordination with the support frame; The bottom end of the telescopic rod is fixedly mounted on the workbench, the top end of the telescopic rod is rotatably hinged to one end of the rotating rod, and the pressure sensor is rotatably hinged to the other end of the rotating rod.

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