A test bench for continuous conductivity testing of lubricating grease and its test method

Abstract

This invention discloses a continuous conductivity testing bench for lubricating grease and its testing method. The test bench includes a grease pump, a conductive base plate, a heating module, and an upper conductive plate. It can continuously measure the dynamic conductivity of the lubricating grease before and after breakdown and before and after blockage at a preset temperature, calculate the average conductivity during the continuous thickness change process, and conclude that the grease thickness is different when breakdown and blockage occur. It obtains the accurate values ​​of the grease thickness in the test area corresponding to each breakdown and blockage. In the blockage analysis, the volume of the grease to be injected into the test area is calculated by integration. Based on the instantaneous volume flow rate detected by the elliptical gear flow meter, the actual volume of the grease to be injected into the test area is calculated, and the flow rate of the grease pump is adjusted to ensure that the difference between the volume of the grease to be injected into the test area and the actual volume of the grease injected into the test area is within a preset range. This avoids the pressure changes caused by insufficient grease thickness or excessive grease affecting the test accuracy.

Description

Technical Field

[0001] This invention relates to the field of electrical conductivity testing technology for lubricating greases, and in particular to a continuous conductivity testing test bench suitable for special lubricating greases, applicable to the testing and analysis of the electrical conductivity of lubricating greases in the fields of electronics, electrical engineering, and mechanics. Background Technology

[0002] Existing devices for testing the conductivity of lubricating greases suffer from insufficient contact and poor repeatability, especially in their inability to continuously monitor conductivity, making it difficult to meet the requirements of industrial R&D and quality control. For example, although the structure described in patent application number 202220427027.9 can achieve resistance measurement, it still lacks key functions such as automatic loading, thickness control, and temperature regulation, and cannot truly simulate the conductive behavior of lubricating grease under actual working conditions. Summary of the Invention

[0003] To address the aforementioned problems, this invention proposes a multi-functional integrated test bench and test method for continuous conductivity testing of lubricating grease, which integrates servo motor control, adjustable displacement, adjustable grease thickness, temperature monitoring, and real-time conductivity acquisition.

[0004] This invention discloses a continuous conductivity testing bench for lubricating grease, comprising a lower base, an upper base, a conductive base plate, and an upper conductive plate. The lower base is fixed to a base; a lower mounting groove is formed at the bottom of the inner cavity of the lower base, and the outer edge of an annular lower insulating outer support is interference-fitted with the side wall of the lower mounting groove, with a sealing ring provided on the outer edge of the lower insulating outer support; the annular conductive base plate is fixed to the inner edge of the lower insulating outer support, and the annular lower insulating inner support is fixed to the inner edge of the conductive base plate; a heating module is fixed to the inner edge of the lower insulating inner support and located at the center of the lower mounting groove; the grease injection hole of the heating module is vertically aligned with the center hole at the bottom of the lower mounting groove, and a sealing ring is fixed inside the grease injection hole; the lower insulating outer support has multiple threaded holes; a grease injection nozzle is embedded in the center hole and the grease injection hole at the bottom of the lower mounting groove, and is connected to a grease injection container via an elliptical gear flow meter and a lubricating grease pump.

[0005] The bottom surface of the upper base has an upper mounting groove; the outer edge of the annular upper insulating outer bracket is interference-fitted with the side wall of the upper mounting groove, and a sealing ring is provided on the outer edge of the upper insulating outer bracket; the annular upper conductive plate is fixed to the inner edge of the upper insulating outer bracket, and the upper insulating inner bracket is fixed to the inner edge of the upper conductive plate; the central hole of the upper insulating inner bracket is vertically aligned with the probe mounting hole opened at the center of the bottom of the upper mounting groove, and a sealing ring is fixed in the central hole of the upper insulating inner bracket; the upper conductive plate and the conductive base plate are vertically aligned and connected to the conductivity measuring instrument; the temperature sensor is fixed on the upper base, the probe of the temperature sensor passes through the probe mounting hole and the central hole of the upper insulating inner bracket, and the bottom surface of the temperature sensor probe is flush with the bottom surface of the upper insulating inner bracket; the upper insulating outer bracket has multiple threaded holes; the upper base and the guide rod fixed on the base form a sliding pair, and form a helical pair with the lead screw, which is driven by a servo motor.

[0006] The method for conducting continuous conductivity tests on lubricating grease using this continuous conductivity testing bench is as follows:

[0007] The grease to be tested is coated on the surface of the conductive base plate. The control module controls the servo motor to drive the lead screw. The angle encoder equipped with the servo motor detects the rotation angle of the servo motor in real time. The control module calculates and stores the moving distance of the upper conductive plate relative to the conductive base plate in real time based on the rotation angle signal of the servo motor and the pitch of the lead screw. When the upper substrate drives the upper conductive plate to descend and contact the grease to be tested, the control module dynamically adjusts the heating power of the heating module according to the real-time temperature detected by the temperature sensor, so that the temperature of the test area between the conductive base plate and the upper conductive plate reaches the preset temperature. Then, the servo motor drives the lead screw, so that the upper substrate drives the upper conductive plate to press down on the conductive base plate at a speed of 5-10 μm / s. The grease to be tested is applied to the surface of the plate. During this process, the conductivity meter transmits the real-time conductivity of the grease to the control module for storage. The control module calculates and stores the time of movement of the upper conductive plate relative to the conductive base plate in real time according to the set servo motor speed. When the conductivity meter detects a sudden change in the conductivity signal of the grease to be tested between the conductive base plate and the upper conductive plate to a high level, the control module determines that the grease to be tested between the conductive base plate and the upper conductive plate has broken down, and calculates the average conductivity of the grease to be tested in the stage before the breakdown. Then, the upper substrate drives the upper conductive plate to continue to press down until it is completely closed with the conductive base plate, and calculates the average conductivity of the grease to be tested in the stage after the breakdown.

[0008] Next, the servo motor drives the lead screw, causing the upper substrate to lift the upper conductive plate at a speed of 5–10 μm / s. The conductivity meter transmits the real-time detected conductivity of the grease to the control module for storage. Simultaneously, the control module, based on the calculated volume of grease to be injected into the test area, controls the grease pump to inject the grease from the injection container into the test area between the conductive base plate and the upper conductive plate via an elliptical gear flow meter and injection nozzle. The elliptical gear flow meter detects the instantaneous volumetric flow rate, and the control module calculates the actual volume of grease injected into the test area based on the instantaneous volumetric flow rate signal, providing feedback. Adjust the flow rate of the grease pump so that the difference between the volume of the grease to be injected into the test area and the actual volume of the grease injected into the test area is within a preset range. When the conductivity meter detects a sudden change in the conductivity signal of the grease to be injected between the conductive base plate and the upper conductive plate to a low level, the control module determines that the grease to be injected between the conductive base plate and the upper conductive plate has entered a blocking state and calculates the average conductivity of the grease to be injected before the blocking stage. Then, the upper substrate drives the upper conductive plate to continue to rise until it just touches the grease to be injected during the descent, and calculates the average conductivity of the grease to be injected after the blocking stage.

[0009] Preferably, the final step includes the following steps: the servo motor drives the lead screw to raise the upper base and the upper conductive plate to the initial position; bolts are screwed into the threaded holes of the upper and lower insulating outer brackets; the lower insulating outer bracket, conductive base plate, lower insulating inner bracket, and heating module are pulled out and residual grease is cleaned; the upper insulating outer bracket, upper conductive plate, and upper insulating inner bracket are pulled out and residual grease is cleaned; the probe of the temperature sensor is cleaned of residual grease; after cleaning, the lower insulating outer bracket, conductive base plate, lower insulating inner bracket, heating module, upper insulating outer bracket, upper conductive plate, and upper insulating inner bracket are reinstalled.

[0010] Preferably, the control module determines whether the upper conductive plate is raised or lowered relative to the conductive base plate based on the signal controlling the forward and reverse rotation of the servo motor, and the grease pump outputs the grease to be tested only when the upper conductive plate is raised.

[0011] Preferably, when the upper conductive plate is raised and the grease to be tested is injected, causing the temperature of the test area to drop, the control module controls the heating module to increase the power so that the test area returns to the preset temperature.

[0012] Preferably, the average conductivity of the grease being tested before and after breakdown is:

[0013]

[0014] in, This represents the time variable at any point during the process from when the upper conductive plate contacts the position of the grease to be tested until it closes with the conductive base plate. For time The conductivity of the lubricating grease at that time, before the breakdown stage The moment when the upper conductive plate descends to contact the grease to be tested. The moment when breakdown occurs, and the subsequent stage after breakdown. The moment when breakdown occurs. This is the moment when the upper conductive plate and the conductive base plate are completely closed.

[0015] Preferably, the average conductivity of the grease to be tested before and after the blocking phase is:

[0016]

[0017] in, This is expressed as the time variable at any point during the process of the upper conductive plate being raised from its position where it joins with the conductive base plate until it just touches the grease to be tested during its descent. For time The conductivity of the lubricating grease at that time blocks the previous stage. This is the moment when the upper conductive plate and the conductive base plate are completely closed. The moment when the blockade occurs, and the subsequent phase. The moment when the blockage occurs. This refers to the moment when the upper conductive plate just touches the grease being tested during its descent from the point where it rises to the point of descent.

[0018] Preferably, the inner cavity of the lower substrate is an inverted frustum, the bottom surface of the upper substrate is a square, and during the lifting of the upper conductive plate, it is set... This is expressed as the time variable at any point during the process of the upper conductive plate being raised from its position where it joins with the conductive base plate until it just touches the grease to be tested during its descent. Let be the time taken for the upper conductive plate to rise from the moment it joined with the conductive base plate to its current position. Then, the inner cavity of the lower substrate at time is... Instantaneous side length of the cross-section at the corresponding upper conductive plate position Distance between the upper conductive plate and the conductive base plate The relation is:

[0019]

[0020] in, The length of the bottom side of the upper base. The inclination angle of the inner cavity side edge of the lower base;

[0021] Then time The volume of grease to be injected into the test area is:

[0022]

[0023] in, This is the redundancy coefficient. For unit conversion factor, For a moment The instantaneous velocity at which the upper conductive plate lifts.

[0024] More preferably, time The actual volume of the grease to be tested in the internal injection test area is:

[0025]

[0026] in, Timing for detection of oval gear flow meter Instantaneous volumetric flow rate.

[0027] Compared with existing technologies, the present invention has the following advantages:

[0028] 1. This invention utilizes a high-precision servo motor to drive a precision ball screw, causing the upper substrate to move up and down along with the upper conductive plate. The distance between the upper conductive plate and the conductive base plate can be adjusted with an accuracy of 0.1–1 μm, ensuring continuous thickness variation during grease compression. This allows for dynamic conductivity measurement before and after breakdown. It also ensures continuous thickness variation as the distance between the upper and lower conductive plates increases, enabling dynamic conductivity measurement before and after interruption. Furthermore, a control module, combined with temperature sensor feedback, controls the heating module to maintain the test area temperature at a preset level. Therefore, this invention can precisely adjust the loading displacement and temperature to simulate the service state of grease under actual working conditions, achieving precise loading, temperature setting, and conductivity detection under corresponding operating conditions. Further, the invention records the conductivity variation curves of grease at different thicknesses at a preset temperature using the control module, identifying conductivity fluctuations and calculating the average conductivity during continuous thickness variation to quantify the stability of grease conductivity. Thus, this invention's test bench features high precision and high automation, making it particularly suitable for evaluating grease conductivity and developing electrical contact lubrication materials.

[0029] 2. This invention not only supports real-time fluctuation analysis and average conductivity analysis of grease conductivity during the breakdown process, but also supports real-time fluctuation analysis and average conductivity analysis of grease conductivity during the blocking process. Furthermore, through independent analysis of the breakdown and blocking processes, it concludes that the grease thickness is different when breakdown and blocking occur, and obtains accurate values ​​of grease thickness in the test area corresponding to each breakdown and blocking process. Specifically, in the blocking analysis, by designing the inner cavity shape of the lower substrate, the cross-section of the lower substrate's inner cavity at the location of the upper conductive plate is correlated with the distance between the upper conductive plate and the conductive base plate. This allows for the calculation of the volume of grease to be injected into the test area at different positions of the upper conductive plate using an integral method. Based on the instantaneous volumetric flow rate detected by an elliptical gear flow meter, the control module calculates the actual volume of grease injected into the test area based on the instantaneous volumetric flow rate signal, and adjusts the grease pump flow rate accordingly, forming a closed-loop control. This ensures that the difference between the volume of grease to be injected into the test area and the actual volume of grease injected into the test area is within a preset range. This guarantees that the test area is always filled with grease during the lifting of the upper conductive plate, accurately controlling the grease thickness within the test area and avoiding pressure changes that could affect test accuracy due to insufficient or excessive grease thickness. Therefore, this invention provides a quantitative basis for the study of the electrical behavior of grease, particularly the conductivity performance during and before and after breakdown and blocking.

[0030] 3. This invention adopts a modular design. The lower insulating outer support, conductive base plate, lower insulating inner support, and heating module can be quickly assembled and disassembled together. Similarly, the upper insulating outer support, upper conductive plate, and upper insulating inner support can also be quickly assembled and disassembled together, facilitating cleaning and repeated testing, and improving testing efficiency and accuracy. Therefore, this invention has a high degree of overall automation and is suitable for high-frequency, multi-batch testing of the conductivity of lubricating greases, especially for developing conductive lubricating grease products. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of a continuous conductivity test bench for lubricating grease according to the present invention.

[0032] Figure 2 This is an assembly diagram of the upper base, upper insulating outer support, upper conductive plate and upper insulating inner support in this invention.

[0033] Figure 3 This is an assembly diagram of the lower part of the base, the lower insulating outer support, the conductive base plate, and the lower insulating inner support in this invention.

[0034] Figure 4 This is a schematic diagram of the assembly of the grease injection container, grease pump, oval gear flow meter, conductivity meter, and control module with the base in this invention. Detailed Implementation

[0035] To better understand the present invention, the invention will be described in detail below with reference to the accompanying drawings.

[0036] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a continuous conductivity test bench for lubricating grease includes a lower base 1, an upper base 5, a conductive base plate 2, and an upper conductive plate 6. The lower base 1 is fixed on a base 18; a lower mounting groove is formed at the bottom of the inner cavity of the lower base 1, and the outer edge of an annular lower insulating outer support 19 is interference-fitted with the side wall of the lower mounting groove, and a sealing ring is provided on the outer edge of the lower insulating outer support 19; the annular conductive base plate 2 is fixed to the inner edge of the lower insulating outer support 19, and the annular lower insulating inner support 20 is fixed to the inner edge of the conductive base plate 2; a heating module 13 is fixed to the inner edge of the lower insulating inner support 20 and is located at the center of the lower mounting groove; the grease injection hole 14 of the heating module 13 is vertically aligned with the center hole at the bottom of the lower mounting groove, and a sealing ring is fixed inside the grease injection hole 14; the lower insulating inner support 20 and the lower insulating outer support 19 are provided inside and outside the conductive base plate 2 to achieve electrical isolation. The lower insulating outer bracket 19 has multiple threaded holes for screwing in bolts, facilitating the removal of the lower insulating outer bracket 19, conductive base plate 2, lower insulating inner bracket 20, and heating module 13, and cleaning residual grease to improve accuracy during repeated tests. The grease injection nozzle 15 is embedded in the center hole and grease injection hole 14 at the bottom of the lower mounting groove, and is connected to the grease injection container 16 via the oval gear flow meter 17 and the grease pump 21.

[0037] The bottom surface of the upper base 5 is provided with an upper mounting groove; the outer edge of the annular upper insulating outer bracket 3 is interference-fitted with the side wall of the upper mounting groove, and a sealing ring is provided on the outer edge of the upper insulating outer bracket 3; the annular upper conductive plate 6 is fixed to the inner edge of the upper insulating outer bracket 3, and the upper insulating inner bracket 7 is fixed to the inner edge of the upper conductive plate 6; the central hole of the upper insulating inner bracket 7 is aligned vertically with the probe mounting hole opened at the center of the bottom of the upper mounting groove, and a sealing ring is fixed in the central hole of the upper insulating inner bracket 7; the upper conductive plate 6 and the conductive... The base plate 2 is aligned vertically and connected to the conductivity measuring instrument 12. The temperature sensor 4 is fixed on the upper base 5. The probe of the temperature sensor 4 passes through the probe mounting hole and the center hole of the upper insulating inner bracket 7, and the bottom surface of the probe of the temperature sensor 4 is flush with the bottom surface of the upper insulating inner bracket 7. The upper insulating outer bracket 3 has multiple threaded holes for screwing in bolts, which facilitates the removal of the upper insulating outer bracket 3, the upper conductive plate 6, and the upper insulating inner bracket 7 to clean residual grease and improve the accuracy during repeated tests. The upper base 5 and the guide rod fixed on the base 18 form a sliding pair, and the lead screw 9 forms a helical pair. The lead screw 9 is driven by the servo motor 8.

[0038] The heating module 13, the grease pump 21 and the servo motor 8 are all controlled by the control module 10. The servo motor 8 is equipped with an angle encoder. The signal output terminals of the angle encoder, the conductivity meter 12, the temperature sensor 4 and the elliptical gear flow meter 17 are all connected to the control module 10, for example, through the wire 11.

[0039] The method for conducting continuous conductivity tests on lubricating grease using this continuous conductivity testing bench is as follows:

[0040] The grease to be tested is coated on the surface of the conductive base plate 2. The control module 10 controls the servo motor 8 to drive the lead screw 9. The angle encoder equipped with the servo motor 8 detects the rotation angle of the servo motor 8 in real time. The control module 10 calculates and stores the moving distance of the upper conductive plate 6 relative to the conductive base plate 2 in real time based on the rotation angle signal of the servo motor 8 and the pitch of the lead screw. This causes the upper substrate 5 to drive the upper conductive plate 6 to descend until it contacts the grease to be tested. (The distance from the initial position of the upper conductive plate 6 to the grease to be tested can be obtained by subtracting the thickness of the coated grease from the known distance from the initial position of the upper conductive plate 6 to the conductive base plate 2.) When the distance between the conductive base plate 2 and the upper conductive plate 6 is reached, the control module 10 dynamically adjusts the heating power of the heating module 13 according to the real-time temperature detected by the temperature sensor 4, so that the temperature of the test area between the conductive base plate 2 and the upper conductive plate 6 reaches the preset temperature, ensuring that the temperature of the grease to be tested is uniform and stable. Then, the servo motor 8 drives the lead screw 9, so that the upper substrate 5 drives the upper conductive plate 6 to slowly press down on the grease to be tested on the surface of the conductive base plate 2 at a speed of 5-10 μm / s. The grease to be tested gradually spreads into a uniform film. During this process, the conductivity meter 12 transmits the real-time detected conductivity of the grease to be tested to the control module 10. The control module 10 stores the time of movement of the upper conductive plate 6 relative to the conductive base plate 2 in real time according to the set rotational speed of the servo motor 8 (obtained from the ratio of rotational angle to rotational speed, or from the clock module of the control module 10). When the conductivity meter 12 detects a sudden change in the conductivity signal of the grease under test between the conductive base plate 2 and the upper conductive plate 6 to a high level, it indicates that the thickness of the grease under test is thin and the electric field strength is high. The control module 10 determines that the grease under test between the conductive base plate 2 and the upper conductive plate 6 has broken down, and calculates the average value of the grease under test in the stage before the breakdown. The conductivity meter can analyze the fluctuation data and average conductivity of the grease under test in the stage before breakdown. Then, the upper substrate 5 drives the upper conductive plate 6 to continue to press down until it is completely closed with the conductive base plate 2. The conductivity meter transmits the real-time detected conductivity of the grease under test to the control module for storage. The control module calculates the average conductivity of the grease under test in the stage after breakdown, thereby analyzing the fluctuation data and average conductivity of the grease under test in the stage after breakdown. The conductivity fluctuation data and average conductivity of the grease under test in the stable stage before and after breakdown can guide the study of the conductivity stability of the grease under test.

[0041] Next, the servo motor 8 drives the lead screw 9, causing the upper base 5 to slowly lift the upper conductive plate 6 at a speed of 5-10 μm / s. The conductivity meter 12 transmits the real-time detected conductivity of the grease to be tested to the control module 10 for storage. Simultaneously, the control module 10, according to the calculated volume of the grease to be injected into the test area, controls the grease pump 21 to inject the grease to be tested from the grease injection container 16 into the test area between the conductive base plate 2 and the upper conductive plate 6 via the elliptical gear flow meter 17 and the grease injection nozzle 15. The elliptical gear flow meter 17 detects the instantaneous volumetric flow rate. The control module 10 calculates the actual volume of the grease to be tested injected into the test area based on the instantaneous volumetric flow rate signal, and adjusts the flow rate of the grease pump 21 (which can be a metering pump) to form a closed-loop control. This ensures that the difference between the volume of the grease to be tested to be injected into the test area and the actual volume of the grease injected into the test area is within a preset range, thereby ensuring that the upper conductive plate 6... During the lifting process, the test area is always filled with the grease to be tested, and the thickness of the grease to be tested in the test area is accurately controlled. As the thickness of the grease to be tested in the test area increases, the electric field strength decreases. When the conductivity meter 12 detects a sudden change in the conductivity signal of the grease to be tested between the conductive base plate 2 and the upper conductive plate 6 to a low level, the control module 10 determines that the grease to be tested between the conductive base plate 2 and the upper conductive plate 6 has switched to an blocked state. The average conductivity of the grease to be tested in the stage before the blockage is calculated, so that the fluctuation data and average conductivity of the grease to be tested in the stage before the blockage can be analyzed. Then, the upper substrate 5 drives the upper conductive plate 6 to continue to lift to the position where it just contacts the grease to be tested during the descent. The conductivity meter transmits the real-time detected conductivity of the grease to be tested to the control module for storage. The control module 10 calculates the average conductivity of the grease to be tested in the stage after the blockage, so that the fluctuation data and average conductivity of the grease to be tested in the stage after the blockage can be analyzed. The control module 10 determines whether the upper conductive plate 6 is raised or lowered relative to the conductive base plate 2 based on the signal controlling the forward and reverse rotation of the servo motor 8, thereby ensuring that the grease pump 21 outputs the grease to be tested only when the upper conductive plate 6 is raised; when the temperature of the test area drops due to the upper conductive plate 6 being raised and the grease to be tested being injected, the control module 10 controls the heating module 13 to automatically increase its power to compensate for the temperature loss and ensure that the test area quickly recovers to the preset temperature.

[0042] Finally, the servo motor 8 drives the lead screw 9, causing the upper base 5 to lift the upper conductive plate 6 to the initial position. Bolts are screwed into the threaded holes of the upper insulating outer bracket 3 and the lower insulating outer bracket 19. The lower insulating outer bracket 19, conductive base plate 2, lower insulating inner bracket 20 and heating module 13 are pulled out to clean the residual grease. The upper insulating outer bracket 3, upper conductive plate 6 and upper insulating inner bracket 7 are pulled out to clean the residual grease. The probe of the temperature sensor 4 is also cleaned of residual grease. After cleaning, the lower insulating outer bracket 19, conductive base plate 2, lower insulating inner bracket 20, heating module 13, upper insulating outer bracket 3, upper conductive plate 6 and upper insulating inner bracket 7 are reinstalled.

[0043] The formula for the conductivity of lubricating grease is:

[0044]

[0045] In the formula, For a moment Electrical conductivity of grease, in S / m; For a moment The resistance of the lubricating grease is expressed in Ω; A is the contact area between the upper conductive plate 6 and the conductive base plate 2, expressed in m².

[0046] The average conductivity of the tested grease before and after breakdown is:

[0047]

[0048] in, This represents the time variable at any point during the process from when the upper conductive plate 6 contacts the position of the grease to be tested until it closes with the conductive base plate 2, before the breakdown. The moment when the upper conductive plate 6 descends to contact the grease to be tested. The moment when breakdown occurs, and the subsequent stage after breakdown. The moment when breakdown occurs. This is the moment when the upper conductive plate 6 and the conductive base plate 2 are completely closed.

[0049] The average conductivity of the grease tested before and after the blocking phase was:

[0050]

[0051] Among them, the pre-blocking stage The moment when the upper conductive plate 6 and the conductive base plate 2 are completely closed. The moment when the blockade occurs, and the subsequent phase. The moment when the blockage occurs. This refers to the moment when the upper conductive plate 6 just touches the position of the grease to be tested during the process of rising and falling.

[0052] In a preferred embodiment, the inner cavity of the lower base 1 is an inverted frustum, the bottom surface of the upper base 5 is a square, and during the upward movement of the upper conductive plate 6, it is set that... This is a time variable expression for any moment during the process of the upper conductive plate 6 rising from its position where it is joined with the conductive base plate 2 until it just touches the position of the grease to be tested during its descent. Let be the time taken for the upper conductive plate 6 to rise from the moment it closes with the conductive base plate 2 to its current position. Then, the inner cavity of the lower base 1 at time is... The instantaneous side length of the cross-section at position 6 of the corresponding upper conductive plate Distance between the upper conductive plate 6 and the conductive base plate 2 The relation is:

[0053]

[0054] Among them, distance That is, time. The corresponding test area is the thickness of the grease to be tested. Let be the side length of the bottom surface of the upper base 5. The inclination angle of the inner cavity side edge of the lower base 1 (the angle between the inclination angle and the vertical axis).

[0055] Then time The volume of grease to be injected into the test area is:

[0056]

[0057] in, As a redundancy factor, it ensures that the volume of the grease to be tested injected into the test area is greater than the required volume, thus avoiding insufficient thickness of the grease to be tested; The unit conversion factor is used in this embodiment. In this embodiment, the units for thickness and length are m, and the unit for volume is mL. For a moment The instantaneous upward velocity of the corresponding upper conductive plate 6, in m / s.

[0058] And time The actual volume of the grease to be tested in the internal injection test area is:

[0059]

[0060] in, The timing of the detection of the elliptical gear flow meter 17 Instantaneous volumetric flow rate, in mL / s.

[0061] This embodiment fully demonstrates that the present invention can meet the requirements of high-precision conductivity testing scenarios, and is particularly suitable for industrial fields such as electric vehicle motor lubricating grease, insulating lubricating materials, and microelectronic contact lubrication.

Claims

1. A grease continuous conductivity test rig comprising a lower base, an upper base, a conductive floor and an upper conductive plate, the lower base being fixed to a base, characterised in that: The lower base has a lower mounting groove at the bottom of its inner cavity. The outer edge of the annular lower insulating outer bracket is press-fitted with the side wall of the lower mounting groove, and a sealing ring is provided on the outer edge of the lower insulating outer bracket. The annular conductive base plate is fixed to the inner edge of the lower insulating outer bracket, and the annular lower insulating inner bracket is fixed to the inner edge of the conductive base plate. The heating module is fixed to the inner edge of the lower insulating inner bracket and is located at the center of the lower mounting groove. The grease injection hole of the heating module is aligned vertically with the center hole at the bottom of the lower mounting groove, and a sealing ring is fixed in the grease injection hole. The lower insulating outer bracket has multiple threaded holes. The grease injection nozzle is embedded in the center hole and the grease injection hole at the bottom of the lower mounting groove and is connected to the grease injection container via an elliptical gear flow meter and a grease pump. The bottom surface of the upper base has an upper mounting groove; the outer edge of the annular upper insulating outer bracket is interference-fitted with the side wall of the upper mounting groove, and a sealing ring is provided on the outer edge of the upper insulating outer bracket; the annular upper conductive plate is fixed to the inner edge of the upper insulating outer bracket, and the upper insulating inner bracket is fixed to the inner edge of the upper conductive plate; the central hole of the upper insulating inner bracket is vertically aligned with the probe mounting hole opened at the center of the bottom of the upper mounting groove, and a sealing ring is fixed in the central hole of the upper insulating inner bracket; the upper conductive plate and the conductive base plate are vertically aligned and connected to the conductivity measuring instrument; the temperature sensor is fixed on the upper base, the probe of the temperature sensor passes through the probe mounting hole and the central hole of the upper insulating inner bracket, and the bottom surface of the temperature sensor probe is flush with the bottom surface of the upper insulating inner bracket; the upper insulating outer bracket has multiple threaded holes; the upper base and the guide rod fixed on the base form a sliding pair, and form a helical pair with the lead screw, which is driven by a servo motor.

2. A method of testing grease for continuous electrical conductivity using the apparatus of claim 1, wherein: The grease to be tested is coated on the surface of the conductive base plate. The control module controls the servo motor to drive the lead screw. The angle encoder equipped with the servo motor detects the rotation angle of the servo motor in real time. The control module calculates and stores the moving distance of the upper conductive plate relative to the conductive base plate in real time based on the rotation angle signal of the servo motor and the pitch of the lead screw. When the upper substrate drives the upper conductive plate to descend and contact the grease to be tested, the control module dynamically adjusts the heating power of the heating module according to the real-time temperature detected by the temperature sensor, so that the temperature of the test area between the conductive base plate and the upper conductive plate reaches the preset temperature. Then, the servo motor drives the lead screw, so that the upper substrate drives the upper conductive plate to press down on the grease to be tested on the surface of the conductive base plate at a speed of 5-10 μm / s. During this process, the conductivity meter transmits the real-time detected conductivity of the grease to be tested to the control module for storage. The control module calculates and stores the moving time of the upper conductive plate relative to the conductive base plate in real time according to the set servo motor speed. When the conductivity meter detects a sudden increase in the conductivity signal of the grease under test between the conductive base plate and the upper conductive plate to a high level, the control module determines that the grease under test between the conductive base plate and the upper conductive plate has broken down, and calculates the average conductivity of the grease under test in the stage before the breakdown; then, the upper substrate drives the upper conductive plate to continue to press down until it is completely closed with the conductive base plate, and calculates the average conductivity of the grease under test in the stage after the breakdown. Next, the servo motor drives the lead screw, causing the upper substrate to lift the upper conductive plate at a speed of 5-10 μm / s. The conductivity meter transmits the real-time detected conductivity of the grease to the control module for storage. At the same time, the control module controls the grease pump to inject the grease from the injection container into the test area between the conductive base plate and the upper conductive plate according to the calculated volume of grease to be injected into the test area. The elliptical gear flow meter detects the instantaneous volumetric flow rate. The control module calculates the actual volume of grease injected into the test area based on the instantaneous volumetric flow rate signal and adjusts the flow rate of the grease pump accordingly to ensure that the difference between the volume of grease to be injected into the test area and the actual volume of grease injected into the test area is within a preset range. When the conductivity meter detects a sudden drop in the conductivity signal of the grease to be tested between the conductive base plate and the upper conductive plate to a low level, the control module determines that the grease to be tested between the conductive base plate and the upper conductive plate has entered a blocking state, and calculates the average conductivity of the grease to be tested in the stage before blocking. Then, the upper substrate drives the upper conductive plate to continue to rise until it just contacts the grease to be tested during the descent, and calculates the average conductivity of the grease to be tested in the stage after blocking.

3. The method for conducting a continuous conductivity test of lubricating grease according to claim 2, characterized in that: Finally, the following steps are performed: The servo motor drives the lead screw to lift the upper base and the upper conductive plate to the initial position. Bolts are screwed into the threaded holes of the upper and lower insulating outer brackets. The lower insulating outer bracket, conductive base plate, lower insulating inner bracket, and heating module are removed and residual grease is cleaned. The upper insulating outer bracket, upper conductive plate, and upper insulating inner bracket are removed and residual grease is cleaned. The probe of the temperature sensor is also cleaned of residual grease. After cleaning, the lower insulating outer bracket, conductive base plate, lower insulating inner bracket, heating module, upper insulating outer bracket, upper conductive plate, and upper insulating inner bracket are reinstalled.

4. The method for conducting a continuous conductivity test of lubricating grease according to claim 2, characterized in that: The control module determines whether the upper conductive plate is raised or lowered relative to the conductive base plate based on the signal controlling the forward and reverse rotation of the servo motor. The grease pump outputs the grease to be tested only when the upper conductive plate is raised.

5. The method for conducting a continuous conductivity test of lubricating grease according to claim 2, characterized in that: When the upper conductive plate is raised and the grease to be tested is injected, causing the temperature of the test area to drop, the control module controls the heating module to increase the power, so that the test area returns to the preset temperature.

6. The method for conducting a continuous conductivity test of lubricating grease according to any one of claims 2 to 5, characterized in that: The average conductivity of the tested grease before and after breakdown is: in, This represents the time variable at any point during the process from when the upper conductive plate contacts the position of the grease to be tested until it closes with the conductive base plate. For time The conductivity of the lubricating grease at that time, before the breakdown stage The moment when the upper conductive plate descends to contact the grease to be tested. The moment when breakdown occurs, and the subsequent stage after breakdown. The moment when breakdown occurs. This is the moment when the upper conductive plate and the conductive base plate are completely closed.

7. The method for conducting a continuous conductivity test of lubricating grease according to any one of claims 2 to 5, characterized in that: The average conductivity of the grease tested before and after the blocking phase was: in, This is a time variable expression for any point in time during the process of the upper conductive plate being raised from its position where it joins with the conductive base plate until it just touches the grease to be tested during its descent. For time The conductivity of the lubricating grease at that time blocks the previous stage. This is the moment when the upper conductive plate and the conductive base plate are completely closed. The moment when the blockade occurs, and the subsequent phase. The moment when the blockage occurs. This refers to the moment when the upper conductive plate just touches the grease being tested during its descent from the point where it rises to the point where it descends.

8. The method for conducting a continuous conductivity test of lubricating grease according to any one of claims 2 to 5, characterized in that: The lower substrate has an inverted frustum-shaped cavity, and the upper substrate has a square base. During the lifting process of the upper conductive plate, it is set... This is a time variable expression for any point in time during the process of the upper conductive plate being raised from its position where it joins with the conductive base plate until it just touches the grease to be tested during its descent. Let be the time taken for the upper conductive plate to rise from the moment it joined with the conductive base plate to its current position. Then, the inner cavity of the lower substrate at time is... Instantaneous side length of the cross-section at the corresponding upper conductive plate position Distance between the upper conductive plate and the conductive base plate The relation is: in, The length of the bottom side of the upper base. The inclination angle of the inner cavity side edge of the lower base; Then time The volume of grease to be injected into the test area is: in, This is the redundancy coefficient. For unit conversion factor, For a moment The instantaneous velocity at which the upper conductive plate lifts.

9. The method for conducting a continuous conductivity test of lubricating grease according to claim 8, characterized in that: time The actual volume of the grease to be tested in the internal injection test area is: in, Timing for detection of oval gear flow meter Instantaneous volumetric flow rate.

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