A friction and lubrication characteristics testing device and method for simulating non-transparent material pairs

Abstract

A friction and lubrication property testing device and method for simulating non-transparent material pairs, which relates to the field of tribological property testing of materials. The present invention solves the problem that existing friction and lubrication property testing devices cannot measure the oil film thickness of non-transparent material pairs. The disc specimen of the present invention is connected to the lower end of the rotating shaft, the three-dimensional force sensor is installed on the translation plate, the ball fixture is installed on the three-dimensional force sensor, the ball specimen is fixed to the upper end of the ball fixture, the ball specimen is in contact with the lower surface of the disc specimen, a nozzle is set near the ball-disc contact area, the lower end of the water pool is connected to the disc specimen, the right end of the probe fixture is connected to the probe adjustment device, the left end of the probe fixture horizontally passes through the outer wall of the water pool and extends into the interior, the ultrasonic probe is fixed to the left end of the probe fixture, and the measurement area of the ultrasonic probe is aligned with the ball-disc contact area. The present invention is based on ultrasonic non-contact oil film thickness measurement technology and three-dimensional force testing technology to achieve friction and lubrication property testing of non-transparent material pairs.

Description

Technical Field

[0001] The present invention relates to the field of tribological property testing of materials, and in particular to a friction and lubrication property testing device and method for simulating a pair of non-transparent materials. Background Art

[0002] The tribological properties of kinematic pair materials under different operating conditions are of great theoretical and engineering significance for the design and operation of mechanical equipment. Lubricant film thickness (lubrication state) and friction coefficient are two key indicators of kinematic pair materials' tribological properties. Friction and lubrication property testing machines can provide preliminary testing of kinematic pairs' tribological properties, playing an important role in academic research and engineering applications. However, existing friction testing machines can only measure the friction coefficient of kinematic pair materials. Most lubricant film thickness testing machines rely on optical interferometry. For example, Chinese invention patent publication CN104154870A, published on November 19, 2014, discloses a method for measuring lubricant film thickness using two-color interferometry. This method is only applicable to measuring the film thickness of pairs made of transparent materials, but not for pairs made of non-transparent materials. This makes it impossible to accurately determine the variation of lubricant film thickness (lubrication) for pairs made of non-transparent metal materials, which make up the majority of engineering applications. Consequently, more accurate design and application guidance cannot be provided. Furthermore, factors such as the brittleness of transparent materials must be considered, resulting in a narrow range of applicable load conditions and difficulty in applying heavy loads.

[0003] In summary, the existing friction and lubrication characteristics testing device has the problem of being unable to measure the oil film thickness of non-transparent material pairs. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that the existing friction and lubrication characteristics testing device cannot measure the oil film thickness of non-transparent material pairs, and further provide a friction and lubrication characteristics testing device and method for simulating non-transparent material pairs.

[0005] The technical solution of the present invention is:

[0006] A friction and lubrication property testing device for simulating non-transparent material pairs includes a frame 1, a disc return drive system 2, a loading system 3, a translation system 4, a lubrication system 5 and a measuring system 6. The disc return drive system 2 is installed on the top table of the frame 1. The disc return drive system 2 includes a rotating shaft 26 and a disc specimen 28. The rotating shaft 26 vertically passes through the table of the frame 1. The disc specimen 28 is horizontally arranged below the table of the frame 1. The center of the disc specimen 28 is connected to the lower end of the rotating shaft 26 through a connecting element. The loading system 3 is installed on the rear side of the frame 1. The loading system 3 includes a vertically arranged loading plate 35. The translation system 4 is horizontally installed on the loading plate 35. The translation system 4 includes a horizontally arranged translation plate 45. The lubrication system 5 is located on the left side of the frame 1. The lubrication system 5 includes a nozzle 55. The measuring system 6 includes a load testing unit and a film thickness testing unit. The load testing unit includes a ball specimen 63, a three-dimensional force sensor 64 and a ball clamp 65. The three-dimensional force sensor 64 is installed on the translation plate 45, the ball fixture 65 is installed on the three-dimensional force sensor 64, the ball test piece 63 is fixed on the upper end of the ball fixture 65, the ball test piece 63 is in contact with the lower surface of the disc test piece 28, and a nozzle 55 is set near the ball-disc contact area. The film thickness test unit includes a pool bracket 61, a pool 62, a probe adjustment device 66, a probe fixture 67 and an ultrasonic probe 68. The pool bracket 61 is inverted and installed below the table of the frame 1, and the pool 62 is inverted and installed below the pool bracket 61. The lower end of the pool 62 is in contact with the disc return line. The disc specimen 28 of the drive system 2 is connected, the probe adjustment device 66 is installed in the middle of the frame 1, the right end of the probe clamp 67 is connected to the probe adjustment device 66, the left end of the probe clamp 67 horizontally passes through the outer wall of the water pool 62 and extends into the interior, the ultrasonic probe 68 is fixed to the left end of the probe clamp 67, the measuring area of the ultrasonic probe 68 is aligned with the ball-disc contact area, and the central axis of the rotating shaft 26 of the disc return drive system 2, the central axis of the ball clamp 65 of the measuring system 6, and the central axis of the ultrasonic probe 68 are located in the same vertical plane.

[0007] Furthermore, the ball specimen 63 and the disc specimen 28 form a friction pair, wherein the ball specimen 63 uses an M50 steel ball or a GCr15 steel ball, and the disc specimen 28 uses an M50 steel disc, an M50NiL steel disc, or a GCr15 steel disc.

[0008] Furthermore, the disc return drive system 2 also includes a motor 21, a motor seat 22, a coupling 23, a bearing seat 24, an inner sleeve 25, a bearing end cover 29, a support bearing 210 and a pre-tightening nut 211. The motor seat 22 is installed on the table of the frame 1, and the motor 21 is installed on the motor seat 22. The rotating shaft of the motor 21 is connected to the upper end of the rotating shaft 26 through the coupling 23. The bearing seat 24 is installed in an inverted manner below the table of the frame 1. The rotating shaft 26 is supported by a pair of face-to-face supported bearings 210 in the bearing seat 24. The top of the support bearing 210 is pre-tightened by the pre-tightening nut 211. The two support bearings 210 are positioned between and below by the inner sleeve 25 and the bearing end cover 29 respectively.

[0009] Furthermore, the loading system 3 also includes a first locking ring 31, a first slider guide device 32, a first screw nut device 33 and a first hand wheel 34. The first slider guide device 32 and the first screw nut device 33 are both vertically installed on the rear side of the frame 1. The lower end of the screw in the first screw nut device 33 is connected to the first hand wheel 34, and the upper end of the screw in the first screw nut device 33 is connected to the first locking ring 31. The loading plate 35 is also connected to the nut seat in the first screw nut device 33 and the slider in the first slider guide device 32.

[0010] Furthermore, the translation system 4 also includes a second handwheel 41, a second screw and nut device 42, a second slider guide device 43 and a second locking ring 44. The second slider guide device 43 and the second screw and nut device 42 are both horizontally installed on the loading plate 35. The left end of the screw in the second screw and nut device 42 is connected to the second handwheel 41, and the right end of the screw in the second screw and nut device 42 is connected to the second locking ring 44. The translation plate 45 is also connected to the nut seat in the second screw and nut device 42 and the slider in the second slider guide device 43.

[0011] Furthermore, the lubrication system 5 includes an oil tank 51, a gear pump 52, an oil supply pipe 53, a throttle valve 54, a nozzle 55, an oil pool 56, an oil return pipe 57 and a drainage cap 58. The front end of the oil supply pipe 53 is inserted into the oil tank 51, the gear pump 52 and the throttle valve 54 are both installed on the oil supply pipe 53, the nozzle 55 is connected to the tail end of the oil supply pipe 53, the nozzle 55 is installed near the ball-disc contact area in the oil pool 56, the oil pool 56 is installed on the translation plate 45, a circular hole is provided at the bottom of the oil pool 56 for the ball clamp to pass through, and a vertically arranged cylindrical cylinder is provided at the opening, the inner diameter of the cylindrical cylinder is larger than the outer diameter of the ball clamp, the drainage cap 58 is mounted on the upper part of the ball clamp, the drainage cap 58 is a circular plate structure with an outer edge inclined downward, the outer diameter of the drainage cap 58 is 2-3 mm larger than the outer diameter of the cylindrical cylinder inside the oil pool, the front end of the return oil pipe 57 is connected to the oil outlet of the oil pool 56, and the tail end of the return oil pipe 57 is inserted into the oil tank 51.

[0012] Furthermore, the load testing unit further includes a three-channel transmitter, a converter and a host computer. The load signal of the three-dimensional force sensor 64 is sequentially transmitted to the host computer through the three-channel transmitter and the converter.

[0013] Furthermore, the film thickness test unit also includes a pulse transceiver, a pulse controller and a data acquisition and storage device. The pulse transceiver and the pulse controller are connected to the ultrasonic probe 68 to trigger the ultrasonic signal and receive the echo signal, and the echo signal is then transmitted to the host computer through the data acquisition and storage device.

[0014] A method for testing the friction and lubrication characteristics of a simulated non-transparent material pair based on the device is implemented by the following steps:

[0015] Step 1: Assembly between the ball and the disc:

[0016] First, the ball test piece 63 and the disc test piece 28 are separated by the loading system 3 to a sufficient distance to facilitate their replacement. Then, the ball test piece 63 is fixed to the upper end of the ball fixture 65. Finally, the disc test piece 28 is mounted on the lower end of the rotating shaft 26 via the disc clamp nut 27.

[0017] Step 2: Adjust the position between the ultrasonic probe and the ball test piece:

[0018] First, the ball specimen 63 is moved to the experimental setting position using the translation system 4 , and then the ultrasonic probe 68 is moved to a position where its axis coincides with the center of the ball specimen 63 using the probe adjustment device 66 ;

[0019] Step 3: Injection of coupling agent:

[0020] First, close the drain hole of the pool 62 and open the water injection hole of the pool 62. Then, fill the pool 62 with pure water and close the water injection hole.

[0021] Step 4: Loading between the ball and the disc:

[0022] The ball specimen 63 is moved upward by the loading system 3 to load the ball specimen 63 and the disc specimen 28. During this process, the loading value is obtained by the three-dimensional force sensor 64. When the loading value reaches the experimental set value, the loading is stopped. At this time, a certain contact load is obtained between the ball specimen 63 and the disc specimen 28.

[0023] Step 5: Continuous supply of lubricating oil:

[0024] Using oil spray lubrication, first check the lubrication system 5 pipeline, then turn on the gear pump 52 to continuously supply lubricating oil to the ball-disc contact area, at this time, a certain oil film thickness is achieved between the ball test piece 63 and the disc test piece 28;

[0025] Step 6: Rotational drive of the disc specimen:

[0026] The disc test piece 28 is driven to rotate by the disc return drive system 2 until the rotation speed of the disc test piece 28 reaches the experimental set value. At this time, a certain sliding speed and friction coefficient are obtained between the ball test piece 63 and the disc test piece 28.

[0027] Step 7: Obtaining lubricating oil film thickness and friction coefficient:

[0028] First, the ultrasonic pulse transceiver and the high-speed data acquisition and storage device are turned on, and the ultrasonic probe 68 starts working. Then, the thickness of the lubricating oil film in operation is measured, and the friction force is measured by the three-dimensional force sensor 64 at the same time. The friction coefficient can be obtained by combining the loading values.

[0029] After the experiment is completed, restore the testing machine to its original state, wipe the equipment clean, save the data, and turn off the power.

[0030] Furthermore, when the friction pair is M50 steel ball-M50 steel disk, the sliding speed is 1 m / s, the contact load is 1 GPa, and the friction coefficient is 0.081-0.148;

[0031] Or: When the friction pair is M50 steel ball-M50NiL steel disc, the sliding speed is 0.1m / s, the contact load is 1GPa, and the friction coefficient is 0.083-0.088;

[0032] Or: When the friction pair is GCr15 steel ball-GCr15 steel disc, the sliding speed is 30mm / s, the contact load is 0.5GPa, and the oil film thickness is 0.33;

[0033] Or: When the friction pair is GCr15 steel ball-GCr15 steel disk, the sliding speed is 60mm / s, the contact load is 0.5GPa, and the oil film thickness is 0.49.

[0034] Compared with the prior art, the present invention has the following effects:

[0035] 1. The present invention uses ultrasonic technology to measure the oil film thickness, which does not require the friction pair to be made of transparent materials, ensuring the authenticity of the workpiece material and making the test closer to the actual situation;

[0036] 2. The present invention is not only applicable to the friction and lubrication property test of the same material pair, but also to the friction and lubrication property test of different material pairs, such as bearing steel-bearing steel pair, bearing steel-ceramic pair, etc.

[0037] 3. The present invention is applicable to a wider range of load conditions. Since there is no need to consider the brittleness of transparent materials, etc., this test fixture can apply heavy loads.

[0038] 4. The present invention uses an immersion focused probe, and the sound pressure distribution near the focus of the focused sound field is relatively regular, which makes it easy to measure the film thickness in the contact area with high measurement accuracy.

[0039] 5. The present invention uses a three-dimensional force sensor, which can realize the simultaneous measurement of multiple data such as friction coefficient and oil film thickness.

[0040] 6. A Chinese invention patent application with publication number CN111982034A, published on November 24, 2020, discloses an ultrasonic detection device for measuring the oil film thickness of a hydrostatic guide rail. This ultrasonic detection device differs from the present invention in the following ways:

[0041] (1) The ultrasonic testing device is designed for testing hydrostatic guide rails, where the friction pair has only surface contact. However, in the present invention, both the upper test disc and the lower test ball are interchangeable. By replacing the lower test piece, different contact forms can be achieved, such as point contact, line contact, and surface contact.

[0042] Different contact forms correspond to different lower specimens. Point contact corresponds to a sphere, line contact to a cylindrical roller, and surface contact to a flat surface formed by cutting away a portion of the top of a sphere. The structure supporting the lower specimen can be adjusted to suit its shape.

[0043] (2) The present invention adopts the oil spraying method to continuously supply oil to the contact area of the test piece, so as to ensure sufficient lubrication and a good lubrication state; by controlling the flow rate, different lubrication states can be formed, such as full film lubrication, mixed lubrication, etc.

[0044] (3) The ultrasonic detection device can only measure the thickness of the oil film, but cannot measure the friction coefficient. However, the present invention can measure the friction coefficient and the oil film thickness simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic structural diagram of a friction and lubrication property testing device for simulating a non-transparent material pair according to the present invention;

[0046] Figure 2 It is a longitudinal sectional view of the friction and lubrication property testing device for simulating a non-transparent material pair according to the present invention;

[0047] Figure 3 A schematic diagram of the structure of the disc return drive system in the friction and lubrication characteristics testing device of the present invention;

[0048] Figure 4 Schematic diagram of the structure of the loading system in the friction and lubrication characteristics testing device of the present invention;

[0049] Figure 5 Schematic diagram of the structure of the translation system in the friction and lubrication characteristics testing device of the present invention;

[0050] Figure 6 Schematic diagram of the structure of the lubrication system in the friction and lubrication characteristics testing device of the present invention;

[0051] Figure 7Schematic diagram of the structure of the measurement system in the friction and lubrication characteristics testing device of the present invention;

[0052] Figure 8 It is a schematic diagram of the ultrasonic wave propagation process of the present invention;

[0053] Figure 9 is a schematic diagram of the lubricating oil film thickness test of the present invention;

[0054] Figure 10 It is a schematic diagram of the friction coefficient test of the present invention.

[0055] In the figure: 1-frame; 2-disc return drive system; 3-loading system; 4-translation system; 5-lubrication system; 6-measuring system; 21-motor; 22-motor seat; 23-coupling; 24-bearing seat; 25-inner sleeve; 26-rotating shaft; 27-disc pressure nut; 28-disc specimen; 29-bearing end cover; 210-support bearing; 211-preload nut; 31-first locking ring; 32-first slider guide assembly; 33-first screw nut assembly; 34-first handwheel; 3 5-loading plate; 41-second handwheel; 42-second screw nut assembly; 43-second slider guide assembly; 44-second locking ring; 45-translation plate; 51-oil tank; 52-gear pump; 53-oil supply pipe; 54-throttle valve; 55-nozzle; 56-oil pool; 57-oil return pipe; 58-drainage cap; 61-water pool bracket; 62-water pool; 63-ball specimen; 64-three-dimensional force sensor; 65-ball fixture; 66-probe adjustment device; 67-probe fixture; 68-ultrasonic probe. DETAILED DESCRIPTION

[0056] Specific implementation method 1: Combination Figures 1 to 71. Description of the present embodiment. A friction and lubrication characteristic testing device for simulating non-transparent material pairings in the present embodiment comprises a frame 1, a disc return drive system 2, a loading system 3, a translation system 4, a lubrication system 5 and a measuring system 6. The disc return drive system 2 is mounted on the top table of the frame 1. The disc return drive system 2 comprises a rotary shaft 26 and a disc specimen 28. The rotary shaft 26 vertically passes through the table of the frame 1. The disc specimen 28 is horizontally arranged below the table of the frame 1. The center of the disc specimen 28 is connected to the lower end of the rotary shaft 26 through a connecting element. The loading system 3 is mounted on the rear side of the frame 1. The loading system 3 comprises a vertically arranged loading plate 35. The translation system 4 is horizontally mounted on the loading plate 35. The translation system 4 comprises a horizontally arranged translation plate 45. The lubrication system 5 is located on the left side of the frame 1. The lubrication system 5 comprises a nozzle 55. The measuring system 6 comprises a load test unit and a film thickness test unit. The load test unit comprises a ball specimen 63, a three-dimensional force sensor 64 and a ball fixture 65. The three-dimensional force sensor 6 4 is mounted on the translation plate 45, the ball fixture 65 is mounted on the three-dimensional force sensor 64, the ball test piece 63 is fixed to the upper end of the ball fixture 65, the ball test piece 63 is in contact with the lower surface of the disc test piece 28, and a nozzle 55 is set near the ball-disc contact area. The film thickness test unit includes a water pool bracket 61, a water pool 62, a probe adjustment device 66, a probe fixture 67 and an ultrasonic probe 68. The water pool bracket 61 is inverted and mounted below the table of the frame 1, and the water pool 62 is inverted and mounted below the pool bracket 61. The lower end of the pool 62 is in contact with the water pool 62. The disc specimen 28 of the disc return drive system 2 is connected, the probe adjustment device 66 is installed in the middle of the frame 1, the right end of the probe clamp 67 is connected to the probe adjustment device 66, the left end of the probe clamp 67 horizontally passes through the outer wall of the water pool 62 and extends into the interior, the ultrasonic probe 68 is fixed to the left end of the probe clamp 67, the measurement area of the ultrasonic probe 68 is aligned with the ball-disc contact area, and the central axis of the rotating shaft 26 of the disc return drive system 2, the central axis of the ball clamp 65 of the measuring system 6, and the central axis of the ultrasonic probe 68 are located in the same vertical plane.

[0057] The disc test piece 28 is mounted on the lower end of the rotating shaft 26 via the disc compression nut 27. The lower end of the water tank 62 is connected to the disc 28 of the disc drive system 2, and the connection is sealed. The probe fixture 67 extends through the outer wall of the water tank 62 and into the interior, and the connection is sealed.

[0058] Among them, the ultrasonic probe 68 uses a water-immersion focused probe. It is required that the water pool 61 be filled with pure water as a coupling agent before work. The upper and lower ends of the water pool 61 are respectively provided with a water inlet and a drain outlet. The position of the ultrasonic probe 68 is adjusted using the probe adjustment device 66, and the measurement area of the ultrasonic probe 68 is required to be aligned with the ball-disc contact area.

[0059] Specific implementation method 2: Combination Figures 1 to 7To explain this embodiment, a ball specimen 63 and a disc specimen 28 form a friction pair. Ball specimen 63 utilizes an M50 steel ball or a GCr15 steel ball, while disc specimen 28 utilizes an M50 steel disc, an M50NiL steel disc, or a GCr15 steel disc. This setup is suitable not only for testing the friction and lubrication properties of pairs made of the same material, but also for measuring the friction and lubrication properties of pairs made of different materials, such as bearing steel-bearing steel pairs and bearing steel-ceramic pairs. Other components and connections are the same as those in the first embodiment.

[0060] Specific implementation method three: Combination Figures 1 to 7 To illustrate this embodiment, the disc return drive system 2 of this embodiment also includes a motor 21, a motor seat 22, a coupling 23, a bearing seat 24, an inner sleeve 25, a bearing end cover 29, a support bearing 210 and a pre-tightening nut 211. The motor seat 22 is installed on the table of the frame 1, and the motor 21 is installed on the motor seat 22. The rotating shaft of the motor 21 is connected to the upper end of the rotating shaft 26 through the coupling 23. The bearing seat 24 is installed in an inverted manner below the table of the frame 1. The rotating shaft 26 is supported by a pair of face-to-face supported bearings 210 in the bearing seat 24. The top of the support bearing 210 is pre-tightened by the pre-tightening nut 211. The two support bearings 210 are positioned between and below by the inner sleeve 25 and the bearing end cover 29 respectively. This configuration requires that the rotation direction of the preload nut 211 be opposite to that of the disc pressure nut 27, and that the motor rotate clockwise during operation (assuming the disc pressure nut 27 is rotated counterclockwise) to prevent the threads from loosening. During operation, the motor 21 drives the rotating shaft 26, which in turn rotates the disc specimen 28. The load on the disc specimen 28 is transmitted to the surface of the frame 1 through the rotating shaft 26, support bearing 210, and bearing seat 24, forming a closed force loop. Other components and connections are the same as those in Specific Embodiments 1 or 2.

[0061] Specific implementation method four: Combination Figures 1 to 7 To describe this embodiment, the loading system 3 of this embodiment also includes a first locking ring 31, a first slider guide rail device 32, a first screw nut device 33 and a first hand wheel 34. The first slider guide rail device 32 and the first screw nut device 33 are both vertically mounted on the rear side of the frame 1. The lower end of the screw in the first screw nut device 33 is connected to the first hand wheel 34, and the upper end of the screw in the first screw nut device 33 is connected to the first locking ring 31. The loading plate 35 is simultaneously connected to the nut seat in the first screw nut device 33 and the slider in the first slider guide rail device 32. With this arrangement, shaking the hand wheel 34 drives the screw to rotate, causing the nut seat to drive the loading plate 35 to move up and down to achieve loading or unloading between the ball discs. When loading or unloading is completed, the locking ring 31 is tightened to prevent the loading plate 35 from sliding down. Other components and connection relationships are the same as those in specific embodiments one, two or three.

[0062] Specific implementation method five: Combination Figures 1 to 7 To describe this embodiment, the translation system 4 of this embodiment also includes a second handwheel 41, a second screw-nut device 42, a second slider guide device 43, and a second locking ring 44. The second slider guide device 43 and the second screw-nut device 42 are both horizontally mounted on the loading plate 35. The left end of the screw in the second screw-nut device 42 is connected to the second handwheel 41, and the right end of the screw in the second screw-nut device 42 is connected to the second locking ring 44. The translation plate 45 is also connected to the nut seat in the second screw-nut device 42 and the slider in the second slider guide device 43. With this arrangement, shaking the handwheel 41 drives the screw to rotate, causing the nut seat to drive the translation plate 45 to move left and right to change the position of the ball-disc contact area. When it moves to the appropriate position, the locking ring 44 is tightened to prevent the translation plate 45 from sliding. Other components and connection relationships are the same as those in specific embodiments one, two, three, or four.

[0063] Specific implementation method six: combination Figures 1 to 7 The lubrication system 5 of this embodiment includes an oil tank 51, a gear pump 52, an oil supply pipe 53, a throttle valve 54, a nozzle 55, an oil pool 56, an oil return pipe 57 and a drainage cap 58. The front end of the oil supply pipe 53 is inserted into the oil tank 51, the gear pump 52 and the throttle valve 54 are both installed on the oil supply pipe 53, the nozzle 55 is connected to the rear end of the oil supply pipe 53, the nozzle 55 is installed near the ball-disc contact area in the oil pool 56, and the oil pool 56 is installed on the flat On the shift plate 45, a circular hole is provided at the bottom of the oil pool 56 for the ball fixture to pass through, and a vertically arranged cylindrical tube is provided at the opening. The inner diameter of the cylindrical tube is larger than the outer diameter of the ball fixture. A drainage cap 58 is mounted on the upper portion of the ball fixture. The drainage cap 58 is a circular plate-shaped structure with a downwardly inclined outer edge. The outer diameter of the drainage cap 58 is 2-3 mm larger than the outer diameter of the cylindrical tube inside the oil pool. The front end of the return oil pipe 57 is connected to the oil outlet of the oil pool 56, and the rear end of the return oil pipe 57 is inserted into the oil tank 51. With this arrangement, during operation, the gear pump 52 draws lubricating oil from the oil tank 51 into the oil supply pipe 53, which is then sprayed into the ball-disc contact area through the nozzle 55. The throttle valve 54 is used to control the oil volume and head. The lubricating oil in the oil pool 56 flows into the oil tank 51 through the return oil pipe 57 under the action of gravity. The other components and connection relationships are the same as those of the first, second, third, fourth, or fifth embodiments.

[0064] Specific implementation method seven: combination Figures 1 to 7 This embodiment describes a load testing unit that also includes a three-channel transmitter, a converter, and a host computer. The load signal from the three-dimensional force sensor 64 is sequentially transmitted to the host computer via the three-channel transmitter and converter. The remaining components and connections are the same as those in Embodiments 1, 2, 3, 4, 5, or 6.

[0065] Specific implementation method eight: combination Figures 1 to 7To describe this embodiment, the film thickness test unit further includes a pulse transceiver, a pulse controller, and a data acquisition and storage device. The pulse transceiver and pulse controller are connected to the ultrasonic probe 68 to trigger ultrasonic signals and receive echo signals. The echo signals are then transmitted to a host computer via the data acquisition and storage device. The remaining components and connections are the same as those in Embodiments 1, 2, 3, 4, 5, 6, or 7.

[0066] Specific implementation method nine: Combination Figures 1 to 10 This embodiment is described. This embodiment is based on a method for testing the friction and lubrication characteristics of a simulated non-transparent material pair. The method for testing the friction and lubrication characteristics of a simulated non-transparent material pair is implemented by the following steps:

[0067] Step 1: Assembly between the ball and the disc:

[0068] First, the ball test piece 63 and the disc test piece 28 are separated by the loading system 3 to a sufficient distance to facilitate their replacement. Then, the ball test piece 63 is fixed to the upper end of the ball fixture 65. Finally, the disc test piece 28 is mounted on the lower end of the rotating shaft 26 via the disc clamp nut 27.

[0069] Step 2: Adjust the position between the ultrasonic probe and the ball test piece:

[0070] First, the ball specimen 63 is moved to the experimental setting position using the translation system 4 , and then the ultrasonic probe 68 is moved to a position where its axis coincides with the center of the ball specimen 63 using the probe adjustment device 66 ;

[0071] Step 3: Injection of coupling agent:

[0072] First, close the drain hole of the pool 62 and open the water injection hole of the pool 62. Then, fill the pool 62 with pure water and close the water injection hole.

[0073] Step 4: Loading between the ball and the disc:

[0074] The ball specimen 63 is moved upward by the loading system 3 to load the ball specimen 63 and the disc specimen 28. During this process, the loading value is obtained by the three-dimensional force sensor 64. When the loading value reaches the experimental set value, the loading is stopped. At this time, a certain contact load is obtained between the ball specimen 63 and the disc specimen 28.

[0075] Step 5: Continuous supply of lubricating oil:

[0076] Using oil spray lubrication, first check the lubrication system 5 pipeline, then turn on the gear pump 52 to continuously supply lubricating oil to the ball-disc contact area, at this time, a certain oil film thickness is achieved between the ball test piece 63 and the disc test piece 28;

[0077] Step 6: Rotational drive of the disc specimen:

[0078] The disc test piece 28 is driven to rotate by the disc return drive system 2 until the rotation speed of the disc test piece 28 reaches the experimental set value. At this time, a certain sliding speed and friction coefficient are obtained between the ball test piece 63 and the disc test piece 28.

[0079] Step 7: Obtaining lubricating oil film thickness and friction coefficient:

[0080] First, the ultrasonic pulse transceiver and the high-speed data acquisition and storage device are turned on, and the ultrasonic probe 68 starts working. Then, the thickness of the lubricating oil film in operation is measured, and the friction force is measured by the three-dimensional force sensor 64 at the same time. The friction coefficient can be obtained by combining the loading values.

[0081] After the experiment is completed, the test machine is restored to its original state, the equipment is cleaned, the data is saved, and the power is turned off. Other components and connection relationships are the same as those of the specific embodiments 1, 2, 3, 4, 5, 6, 7 or 8.

[0082] Specific implementation method ten: Combination Figures 1 to 10 To illustrate this embodiment, when the friction pair is M50 steel ball-M50 steel disk, the sliding speed is 1 m / s, the contact load is 1 GPa, and the friction coefficient is 0.081-0.148;

[0083] Or: When the friction pair is M50 steel ball-M50NiL steel disc, the sliding speed is 0.1m / s, the contact load is 1GPa, and the friction coefficient is 0.083-0.088;

[0084] Or: When the friction pair is GCr15 steel ball-GCr15 steel disc, the sliding speed is 30mm / s, the contact load is 0.5GPa, and the oil film thickness is 0.33;

[0085] Or: When the friction pair is a GCr15 steel ball-GCr15 steel disk, the sliding speed is 60 mm / s, the contact load is 0.5 GPa, and the oil film thickness is 0.49. The other components and connection relationships are the same as those of the first, second, third, fourth, fifth, sixth, seventh, eighth, or ninth embodiment.

[0086] How it works

[0087] Combine Figures 1 to 10 The working principle of the friction and lubrication characteristics testing device for simulating non-transparent material pairs is described below:

[0088] (1) Principle of lubricating oil film thickness test

[0089] In the contact area between the ball specimen 63 and the disc specimen 28, the ball can be approximately treated as a plane. The propagation process of ultrasonic waves in the three-layer medium structure of disc-oil film-ball is as follows: Figure 7As shown, when the incident wave reaches interface 1, it will be reflected and transmitted. When the transmitted part passes through the oil film layer and reaches interface 2, it will continue to be reflected and transmitted. This cycle will continue, and the sound wave will be reflected and transmitted multiple times at the interface.

[0090] The reflection coefficient modeling based on the wave superposition principle is as follows:

[0091] R1=I·S 12

[0092] R2=I·T 12 ·S 23 ·T 21 ·e 2iωh / c

[0093] R3=I·T 12 ·S 23 ·T 21 ·e 2iωh / c [S 21 ·S 23 ·e 2iωh / c ]

[0094] …

[0095] R n =I·T 12 ·S 23 ·T 21 ·e 2iωh / c [S 21 ·S 23 ·e 2iωh / c ] n-2

[0096] R t =R1+R2+R3+…+R n

[0097] When n approaches infinity,

[0098]

[0099] Where I is the incident wave, R1, R2, R3, ..., R n is the recovered reflected wave, R t is the reflected signal (i.e. the sum of reflected waves), ω is the angular frequency of the sound wave, h is the oil film thickness, c is the speed of sound in the oil film, S mn 、T mn are the reflection coefficient and transmission coefficient at the interface of medium m and medium n respectively. mn 、T mn satisfy:

[0100]

[0101] S nm =-Smn

[0102] T mn =1+S mn

[0103] Where z is the acoustic impedance, which is determined by the product of the density of the medium and the speed of sound in the medium.

[0104] The reflection coefficient R is the ratio of the sum of the reflected echoes to the incident wave:

[0105]

[0106] The oil film is extremely thin, and its thickness is much smaller than the ultrasonic wavelength. ωh / c is close to 0, so the e 2iωh / c When performing Taylor expansion, only the first-order terms in the expansion are retained, and z2 is much smaller than z1 and z3, then:

[0107]

[0108] Where ρ is the density of the oil.

[0109] The reflection coefficient amplitude is:

[0110]

[0111] The oil film thickness is:

[0112]

[0113] The reflection coefficient of the metal-oil interface cannot be measured directly, but is calculated indirectly using the known reflection coefficient of the reference medium:

[0114]

[0115] Among them, R r is the reflection coefficient of the reference medium, A r (f) is the reflection amplitude of the reference signal, and A(f) is the reflection amplitude of the oil film layer.

[0116] (2) Friction coefficient test principle

[0117] The three-dimensional force sensor 64 can simultaneously measure the force values in three directions, including the longitudinal pressure F and the transverse friction f between the ball and the disc. The friction coefficient is:

[0118]

[0119] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A friction and lubrication properties testing device for simulating a pair of non-transparent materials, characterized by: The invention comprises a frame (1), a disc return drive system (2), a loading system (3), a translation system (4), a lubrication system (5) and a measuring system (6), wherein the disc return drive system (2) is installed on the top table of the frame (1), the disc return drive system (2) comprises a rotary shaft (26) and a disc specimen (28), the rotary shaft (26) vertically passes through the table of the frame (1), the disc specimen (28) is horizontally arranged below the table of the frame (1), the center of the disc specimen (28) is connected to the lower end of the rotary shaft (26) through a connecting element, the loading system (3) is installed on the rear side of the frame (1), the loading system (3) comprises a vertically arranged loading plate (35), the translation system (4) is horizontally installed on the loading plate (35), and the translation system (4) comprises a horizontally arranged The translation plate (45) is arranged on the left side of the frame (1). The lubrication system (5) includes an oil tank (51), a gear pump (52), an oil supply pipe (53), a throttle valve (54), a nozzle (55), an oil pool (56), an oil return pipe (57) and a drainage cap (58). The front end of the oil supply pipe (53) is inserted into the oil tank (51). The gear pump (52) and the throttle valve (54) are both installed on the oil supply pipe (53). The nozzle (55) is connected to the tail end of the oil supply pipe (53). The nozzle (55) is installed near the ball-disc contact area in the oil pool (56). The oil pool (56) is installed on the translation plate (45). A circular hole is provided at the bottom of the oil pool (56) for the ball fixture to pass through, and a vertically arranged cylindrical barrel is provided at the opening. The inner diameter of the cylindrical barrel is larger than the inner diameter of the ball. The outer diameter of the fixture is 2-3 mm. The drainage cap (58) is mounted on the upper part of the ball fixture. The drainage cap (58) is a circular plate-shaped structure with an outer edge tilted downward. The outer diameter of the drainage cap (58) is 2-3 mm larger than the outer diameter of the cylindrical tube inside the oil pool. The front end of the return oil pipe (57) is connected to the oil outlet of the oil pool (56). The tail end of the return oil pipe (57) is inserted into the oil tank (51). The measuring system (6) includes a load test unit and a film thickness test unit. The load test unit includes a ball specimen (63), a three-dimensional force sensor (64) and a ball fixture (65). The three-dimensional force sensor (64) is installed on the translation plate (45). The ball fixture (65) is installed on the three-dimensional force sensor (64). The ball specimen (63) is fixed on the upper end of the ball fixture (65). The ball specimen (63) and the disc specimen (28) are connected. ) is in contact with the lower surface of the disc, a nozzle (55) is set near the ball-disc contact area, the film thickness test unit includes a water pool bracket (61), a water pool (62), a probe adjustment device (66), a probe clamp (67) and an ultrasonic probe (68), the water pool bracket (61) is inverted and installed below the table of the frame (1), the water pool (62) is inverted and installed below the water pool bracket (61), the upper end and the lower end of the water pool (61) are respectively provided with a water inlet and a drain outlet, the lower end of the water pool (62) is connected to the disc test piece (28) of the disc return drive system (2) and a seal is made at the connection, before work, the water pool (61) is filled with pure water as a coupling agent, the probe adjustment device (66) is installed in the middle of the frame (1), and the right end of the probe clamp (67) is connected to the probe adjustment device (66),The left end of the probe fixture (67) passes horizontally through the outer wall of the pool (62) and extends into the interior and is sealed at the connection. The ultrasonic probe (68) is a water-immersion focusing probe. The ultrasonic probe (68) is fixed to the left end of the probe fixture (67). The position of the ultrasonic probe (68) is adjusted using the probe adjustment device (66) so that the measurement area of the ultrasonic probe (68) is aligned with the ball-disc contact area. The central axis of the rotary shaft (26) of the disc return drive system (2), the central axis of the ball fixture (65) of the measuring system (6), and the central axis of the ultrasonic probe (68) are located in the same vertical plane.

2. The friction and lubrication characteristics testing device for simulating a non-transparent material pair according to claim 1, characterized in that: The ball test piece (63) and the disc test piece (28) form a friction pair, wherein the ball test piece (63) adopts an M50 steel ball or a GCr15 steel ball, and the disc test piece (28) adopts an M50 steel disc, an M50NiL steel disc or a GCr15 steel disc.

3. The friction and lubrication characteristics testing device for simulating a non-transparent material pair according to claim 1, characterized in that: The disc return drive system (2) also includes a motor (21), a motor seat (22), a coupling (23), a bearing seat (24), an inner sleeve (25), a bearing end cover (29), a support bearing (210) and a pre-tightening nut (211). The motor seat (22) is mounted on the table of the frame (1), the motor (21) is mounted on the motor seat (22), the rotating shaft of the motor (21) is connected to the upper end of the rotary shaft (26) through the coupling (23), the bearing seat (24) is inverted and mounted below the table of the frame (1), the rotary shaft (26) is supported by a pair of support bearings (210) mounted face to face in the bearing seat (24), the upper part of the support bearing (210) is pre-tightened by the pre-tightening nut (211), and the inner sleeve (25) and the bearing end cover (29) are respectively positioned between and below the two support bearings (210).

4. The friction and lubrication characteristics testing device for simulating a non-transparent material pair according to claim 1, characterized in that: The loading system (3) further comprises a first locking ring (31), a first slider guide rail device (32), a first screw nut device (33) and a first hand wheel (34). The first slider guide rail device (32) and the first screw nut device (33) are both vertically mounted on the rear side of the frame (1). The lower end of the screw in the first screw nut device (33) is connected to the first hand wheel (34), the upper end of the screw in the first screw nut device (33) is connected to the first locking ring (31), and the loading plate (35) is simultaneously connected to the nut seat in the first screw nut device (33) and the slider in the first slider guide rail device (32).

5. The friction and lubrication characteristics testing device for simulating a pair of non-transparent materials according to claim 4, characterized in that: The translation system (4) further comprises a second hand wheel (41), a second lead screw nut device (42), a second slider guide rail device (43) and a second locking ring (44). The second slider guide rail device (43) and the second lead screw nut device (42) are both horizontally mounted on the loading plate (35). The left end of the lead screw in the second lead screw nut device (42) is connected to the second hand wheel (41), the right end of the lead screw in the second lead screw nut device (42) is connected to the second locking ring (44), and the translation plate (45) is simultaneously connected to the nut seat in the second lead screw nut device (42) and the slider in the second slider guide rail device (43).

6. The friction and lubrication characteristics testing device for simulating a pair of non-transparent materials according to claim 5, characterized in that: The load test unit further comprises a three-channel transmitter, a converter and a host computer, and the load signal of the three-dimensional force sensor (64) is sequentially transmitted to the host computer through the three-channel transmitter and the converter.

7. The friction and lubrication characteristics testing device for simulating a pair of non-transparent materials according to claim 6, characterized in that: The film thickness test unit also includes a pulse transceiver, a pulse controller and a data acquisition and storage device. The pulse transceiver and the pulse controller are connected to the ultrasonic probe (68) to trigger the ultrasonic signal and receive the echo signal. The echo signal is then transmitted to the host computer through the data acquisition and storage device.

8. A method for testing the friction and lubrication properties of a simulated non-transparent material pair based on claim 7, characterized in that: The friction and lubrication characteristics testing method of simulating a non-transparent material pair is achieved by the following steps: Step 1: Assembly between the ball and the disc: First, the ball test piece (63) and the disc test piece (28) are separated to a sufficient distance by using the loading system (3) so as to facilitate the replacement of the ball test piece (63) and the disc test piece (28). Then, the ball test piece (63) is fixed to the upper end of the ball clamp (65). Finally, the disc test piece (28) is mounted on the lower end of the rotary shaft (26) through the disc clamping nut 27. Step 2: Adjust the position between the ultrasonic probe and the ball test piece: First, the ball test piece (63) is moved to the experimental setting position using the translation system (4), and then the ultrasonic probe (68) is moved to a position where its axis coincides with the center of the ball test piece (63) using the probe adjustment device (66); Step 3: Injection of coupling agent: First, close the drain hole of the pool (62), open the water injection hole of the pool (62), then fill the pool (62) with pure water and close the water injection hole; Step 4: Loading between the ball and the disc: The ball test piece (63) is moved upward by the loading system (3) to load the ball test piece (63) and the disc test piece (28). During the process, the loading value is obtained by the three-dimensional force sensor (64). When the loading value reaches the experimental set value, the loading is stopped. At this time, a certain contact load is obtained between the ball test piece (63) and the disc test piece (28); Step 5: Continuous supply of lubricating oil: Using the oil injection lubrication method, first, check the lubrication system (5) pipeline, then turn on the gear pump (52) to continuously supply lubricating oil to the ball-disc contact area, at which time a certain oil film thickness is obtained between the ball test piece (63) and the disc test piece (28); Step 6: Rotational drive of the disc specimen: The disc test piece (28) is driven to rotate by the disc return drive system (2) so that the rotation speed of the disc test piece (28) reaches the experimental set value, at which time a certain sliding speed and friction coefficient are obtained between the ball test piece (63) and the disc test piece (28); Step 7: Obtaining lubricating oil film thickness and friction coefficient: First, the ultrasonic pulse transceiver and the high-speed data acquisition and storage device are turned on, and the ultrasonic probe (68) starts working. Then, the thickness of the lubricating oil film in operation is measured, and the friction force is measured by the three-dimensional force sensor (64). The friction coefficient can be obtained by combining the loading value. After the experiment is completed, restore the testing machine to its original state, wipe the equipment clean, save the data, and turn off the power.

9. The method for testing the friction and lubrication properties of a simulated non-transparent material pair according to claim 8, characterized in that: When the friction pair is M50 steel ball-M50 steel disc, the sliding speed is 1m / s, the contact load is 1GPa, and the friction coefficient is 0.081~0.148; Or: When the friction pair is M50 steel ball-M50NiL steel disc, the sliding speed is 0.1m / s, the contact load is 1GPa, and the friction coefficient is 0.083-0.088; Or: When the friction pair is GCr15 steel ball-GCr15 steel disc, the sliding speed is 30mm / s, the contact load is 0.5GPa, and the oil film thickness is 0.33; Or: When the friction pair is GCr15 steel ball-GCr15 steel disk, the sliding speed is 60mm / s, the contact load is 0.5GPa, and the oil film thickness is 0.49.

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