Multifunctional lubricant friction test device and application

Abstract

The invention provides a multifunctional lubricant friction test device and application, the device comprises a shell, a top cover and a first sealing cavity, the first sealing cavity is internally provided with a modularized friction execution mechanism composed of an upper conversion unit, a test friction pair and a lower conversion unit, and the friction execution mechanism can be integrally replaced; the upper unit is connected with an external drive, and the lower unit is fixed to the shell. Friction force is measured through the force arm rod, and temperature is monitored by the temperature probe. According to the design, the problems that a traditional device is single in function, high in cost and difficult to simulate real working conditions are solved, point, line and surface contact and integrated testing of pure sliding, rolling and sliding-rolling composite motion are achieved through a modular structure, the testing efficiency and flexibility are remarkably improved, the equipment replacement cost is reduced, the complex working conditions can be simulated more truly, and the test efficiency is improved. And a reliable, economical and efficient experimental means is provided for lubricant performance evaluation and life prediction.

Description

Technical Field

[0001] This invention belongs to the field of lubrication technology and relates to a multifunctional lubricant friction testing device and its application. Background Technology

[0002] Lubricating greases are crucial for ensuring the long-term reliable operation of transmission components such as bearings and gears. The lubrication performance and service life of lubricants are their core performance indicators. Currently, lubricant evaluation typically employs various friction testing machines, including four-ball machines, Timken friction testing machines, Flaxe friction testing machines, FZG gear testing machines, and FE8 and FE9 bearing testing machines. However, these machines generally suffer from limitations such as limited friction types, high testing costs, long testing cycles, and large sample requirements, resulting in low efficiency in evaluating lubricant lubrication life. To assess lubricant service life, the industry also frequently uses simple thermal oxidation testing methods such as oven oxidation, rotating oxygen bombs, and heat pipe oxidation. However, these methods fail to realistically simulate the tribochemical reactions experienced by lubricants in actual service and their impact on service life, leading to discrepancies between life assessment results and actual operating conditions.

[0003] Therefore, there is an urgent need for a testing device and method to solve the problems of the current friction testing machines, such as the single friction mode, high testing cost, long testing cycle, low efficiency in evaluating the lubricant lubrication life, and the deviation of simple thermal oxidation in evaluating the lubricant life.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a multifunctional lubricant friction testing device and its application, which can overcome the deficiencies of traditional lubricant friction testing, realize the testing of lubricant friction performance under various contact forms such as point, line, and surface and various motion forms such as pure sliding, rolling, and sliding-rolling, while achieving low-cost, high-efficiency and more realistic lubricant life evaluation.

[0006] To achieve the above and other related objectives, the present invention provides a multifunctional lubricant friction testing device, comprising:

[0007] case;

[0008] Top cover, which seals with the housing to form a first sealed cavity;

[0009] A friction actuator is housed in the first sealed cavity. The friction actuator includes an upper conversion unit, a test friction pair, and a lower conversion unit. The test friction pair is disposed between the upper conversion unit and the lower conversion unit. The upper conversion unit has an upwardly extending drive connection portion that passes through a first through hole provided on the top cover for connecting an external rotary drive device. The upper conversion unit is detachably connected to the top cover. The lower conversion unit is installed at the bottom of the housing.

[0010] A force measuring unit, the force measuring unit including a lever arm, the first end of the lever arm being fixed to the outer wall of the housing, for detecting the frictional force or frictional torque generated by the test friction pair and transmitted through the housing;

[0011] A temperature sensing unit extends into the first sealed chamber through a second through hole located at the bottom of the housing and forms a sealed connection with the housing.

[0012] Optionally, it also includes a temperature control mechanism; the temperature control mechanism is any one or a combination of two of the following:

[0013] (1) A temperature control jacket fixed to the outside of the housing, wherein the inner wall of the temperature control jacket and the outer wall of the housing form a second sealed cavity; the temperature control jacket is provided with a temperature control interface communicating with the second sealed cavity;

[0014] (2) A heating device provided on the housing.

[0015] Optionally, the up-conversion unit includes an upper cylindrical boss, a main cylinder, and a lower cylindrical boss arranged coaxially; the upper cylindrical boss is used to pass through the top cover and has the smallest outer diameter; the main cylinder has the largest outer diameter; and the outer diameter of the lower cylindrical boss is between the two.

[0016] Optionally, the upconversion unit is further provided with a plurality of axial holes, which are evenly distributed along the circumference of the upconversion unit.

[0017] Optionally, the friction actuator constitutes an adapter module that can be replaced as a whole; wherein, the up-conversion unit and the down-conversion unit can be connected to the corresponding matching interface on the main body of the device through a unified mechanical interface.

[0018] Optionally, the mechanical interface is a detachable interface, allowing the upper conversion unit to be separated from the top cover, and the lower conversion unit to be separated from the bottom of the housing.

[0019] Optionally, the test friction pair is a customized friction pair or a standard bearing friction pair; the customized friction pair includes an upper pressure plate and a lower pressure plate; wherein, the customized friction pair is a slanted roller friction pair or a ring friction pair; the slanted roller friction pair further includes a slanted roller disposed between the upper pressure plate and the lower pressure plate.

[0020] Optionally, the standard bearing is one of a radial rolling bearing, a thrust rolling bearing, or an angular contact rolling bearing.

[0021] Optionally, the customized friction pair is a slanted roller friction pair, wherein the slanted rollers are arranged at intervals through the first mounting holes in the first retainer; the first retainer is disposed on a limiting member, the limiting member having a first boss extending radially outward, the first boss being coaxial with and clearance-fitted with the first retainer, so that the first retainer can rotate around the limiting member; the limiting member is fixed relative to the lower pressure plate.

[0022] Based on the aforementioned multifunctional lubricant friction testing device, the present invention also proposes applications of the device, including:

[0023] Select the appropriate test friction pair and the corresponding up-conversion unit and down-conversion unit according to the target test conditions;

[0024] The test lubricant is injected into the sealed chamber of the device, and after the lubricant is injected and before the chamber is sealed, the test friction pair, the upper conversion unit and the lower conversion unit are installed.

[0025] Set the normal load, initial temperature, and drive speed, start the test, and drive the test friction pair to run;

[0026] During the experiment, the frictional force or frictional torque measured by the force measurement unit and the lubricant temperature measured by the temperature sensing unit were monitored and recorded in real time.

[0027] After the experiment, the lubricant was collected and analyzed, the friction pairs were tested and analyzed, and the lubrication performance and life of the lubricant were comprehensively judged.

[0028] As described above, this invention discloses a multifunctional lubricant friction testing device and method. The device includes a housing, a top cover, and a first sealed cavity. A modular friction actuator is housed within the first sealed cavity, comprising an upper conversion unit, a test friction pair, and a lower conversion unit, and can be replaced as a whole through a unified mechanical interface. The upper conversion unit is connected to an external drive, and the lower conversion unit is fixed to the housing. A force measurement unit detects the transmitted frictional force through a lever arm fixed to the housing, and a temperature sensing unit monitors the temperature inside the cavity through a probe. This invention overcomes the shortcomings of traditional lubricant friction testing devices, such as limited functionality, high cost, and difficulty in simulating real-world working conditions. By employing a modular friction actuator that can be replaced as a whole, integrated testing of lubricant friction performance under various contact forms (point, line, surface) and pure sliding, rolling, and sliding-rolling composite motions is achieved. This design significantly improves testing efficiency, reduces the cost of replacing the entire device, and allows for flexible combination of modules to make test conditions closer to actual complex working conditions, thus providing a more reliable, economical, and efficient experimental method for lubricant performance evaluation and life prediction. Attached Figure Description

[0029] Housing This is a cross-sectional structural diagram of the multifunctional lubricant friction testing device in this embodiment.

[0030] Peripheral boss This is a schematic diagram of the top inner cavity of the multifunctional lubricant friction testing device in this embodiment.

[0031] Positioning column This is a schematic diagram of the bottom structure of the multifunctional lubricant friction testing device in this embodiment.

[0032] Top cover This is an explosion effect diagram of the multifunctional lubricant friction test device in this embodiment.

[0033] First sealing cavity This is a schematic diagram of the inclined roller friction pair in this embodiment.

[0034] First through hole This is a schematic diagram of the upper pressure plate in the inclined roller friction pair of this embodiment.

[0035] Upper conversion unit This is a schematic cross-sectional view of the assembled inclined roller friction pair in this embodiment.

[0036] Upper cylindrical boss This is a schematic diagram of the downconversion unit in this embodiment.

[0037] Positioning key This is a schematic diagram of the device structure for testing after the inclined roller friction pair in Embodiment 2 is assembled.

[0038] Main body cylinder The curves show the frictional force variation of different gear oils in this second embodiment.

[0039] Axial hole This is the oil temperature change curve for different gear oils in Example 2.

[0040] Lower cylindrical boss This is a schematic cross-sectional view of the thrust roller bearing after it is installed with the upper and lower conversion units in this embodiment 2.

[0041] Explanation of reference numerals in the attached figures

[0042] 100 Lower conversion unit 101 Positioning hole 110 Second mounting hole 120 Flow-through hole 130 Mounting table 140 Mounting groove 200 Test friction pair 210 Upper pressure plate 211 Inclined roller 220 First retainer 221 Limiting piece 230 Threaded hole 300 Second boss 310 First boss 320 Lower pressure plate 330 Force arm rod 340 Fourth through hole 350 Rectangular cutout 400 Rectangular boss 410 Third through hole 420 Thermocouple 421 Lead wire groove 422 Second through hole 423 Lead wire 424 Second cutout 425 Lead wire hole 430 Heating hole 500 First cutout 510 Third cutout 520 Temperature control jacket 530 Temperature control interface 540 Second sealing cavity 600 Handle 601 First base ring 602 Raceway 610 Second base ring 620 Tester base 621 Chuck 622 Tester spindle 630 Ball 640 Second retainer 710 Figure 1 711 Figure 8 720 Figures 1-3 800 Figure 1 900 Figure 3 901 Figure 1 910 Figures 1-3 920 Figure 1 930 Figure 3 940 Figures 1-4 950 Figure 1 960 Figure 9 Detailed Implementation

[0043] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0044] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0045] Example 1

[0046] This embodiment provides a multifunctional lubricant friction testing device, which will be described below in conjunction with the appendix to the instruction manual. Figure 1 ~Appendix Figure 8 This document introduces and explains a multifunctional lubricant friction testing device. The device includes: a housing 100, a top cover 120, a force measuring unit, a temperature sensing unit, and a friction actuator.

[0047] The housing 100 and the top cover 120 seal to form a first sealed cavity 130;

[0048] The friction actuator is housed in the first sealed cavity 130. The friction actuator includes an upper conversion unit 200, a test friction pair 400, and a lower conversion unit 300. The test friction pair 400 is clamped and fixed between the upper conversion unit 200 and the lower conversion unit 300. The upper conversion unit 200 has an upwardly extending drive connection portion that passes through a first through hole 140 provided on the top cover 120 for connecting an external rotary drive device. The upper conversion unit 200 is detachably connected to the top cover 120. The lower conversion unit 300 is installed at the bottom of the housing 100.

[0049] Specifically, the test apparatus is sealed together with the housing 100 and the top cover 120 to form a closed, pressurized first sealed cavity 130. The first sealed cavity 130 enables environmental isolation and atmosphere control. By filling it with inert gas, air, or a gas mixture, it simulates different oxidation conditions, coupling friction and oxidation processes to closely approximate actual working conditions. Simultaneously, the first sealed cavity 130 contains lubricant and prevents leakage, ensuring stable oil levels, avoiding contamination, and providing a basis for measuring lubricant consumption. Furthermore, this sealed connection provides a stable mounting base for the internal friction actuator and the external measuring unit, and effectively transmits the frictional force generated by the test friction pair 400 to the subsequent force measuring unit.

[0050] As an example, the top cover 120 is sealed to the housing 100 via a threaded connection. Specifically, the upper half of the inner cavity of the housing 100 has internal threads, and the corresponding position on the outer wall of the top cover 120 has external threads. The two are fixed together by threaded engagement, thereby forming a reliable seal. In addition, the lower half of the outer wall of the housing 100 includes a peripheral boss 101 for integrating subsequent force measurement units and temperature sensing units. Of course, the top cover 120 and the housing 100 can also be sealed together in other ways, not limited to a threaded connection.

[0051] Specifically, in the friction actuator, the drive connection of the upper conversion unit 200 serves as the power input end, connecting to an external drive device to transmit rotational motion and load. The test friction pair 400, as the friction core, can simulate the actual contact states of bearings, gears, guide rails, etc., by selecting different forms. The lower conversion unit 300 provides support and positioning for the test friction pair 400, bearing the load and friction force. This modular design enables a single device to perform the functions of multiple traditional dedicated testing machines (such as four-ball machines, pin-disc machines, and roller testing machines), achieving a comprehensive evaluation of the lubrication performance of lubricants under various contact and motion forms with low cost and low space occupation, significantly improving testing efficiency and equipment utilization.

[0052] The force measurement unit includes a lever arm 500, the first end of which is fixed to the outer wall of the housing 100, for detecting the frictional force or frictional torque generated by the test friction pair 400 and transmitted through the housing 100.

[0053] Specifically, lever arm 500 serves as a force sensing transmission and amplification mechanism. The first end of lever arm 500 senses minute deformations or torques and converts them into electrical signals that can be accurately measured by force sensors (such as strain gauges or torque sensors) connected to the second end of lever arm 500. This enables in-situ, online, and highly sensitive measurement of frictional force, avoiding the additional friction and errors introduced by external sensors. Combined with precise control of rotational speed and load, the coefficient of friction can be directly calculated, providing real-time and accurate data for evaluating the friction-reducing and anti-wear performance of lubricants.

[0054] In one specific embodiment, see Figure 5 To ensure stable installation of the lever arm 500, a first notch 630 is provided on the outer peripheral boss 101 of the side wall of the housing 100 for installation. A rectangular boss 530 is provided at the first end of the lever arm 500, with third through holes 540 on both sides of the rectangular boss 530. A fixing hole is provided at the corresponding position of the first notch 630, allowing installation to be completed by tightening screws. A rectangular groove 520 is provided at the second end of the lever arm 500, with a fourth through hole 510 in its middle for connecting an external force sensor to transmit the frictional force or frictional torque generated by the test friction pair 400 during testing to the external force sensor.

[0055] The temperature sensing unit passes through the second through hole 602 located at the bottom of the housing 100, extends into the first sealed chamber, and forms a sealed connection with the housing to monitor the temperature of the test friction pair 400 or the lubricant.

[0056] For details, please refer to Figures 4-7 In this embodiment, a thermocouple 600 is selected as the temperature sensing unit. Its installation and signal output are as follows: The temperature probe of the thermocouple 600 extends into the first sealed cavity 130 through a second through hole 602 located at the bottom of the housing 100. The front end of the thermocouple 600 has an external thread, which connects to the second through hole 602 via the external thread, thus forming a sealed connection. This allows for monitoring the real-time temperature near the contact area of ​​the test friction pair 400 or the lubricant, and the transmission of test data to the outside, achieving functions such as real-time temperature detection, over-temperature protection, and simulation of complex thermal states. Of course, other types of temperature sensing units can also be used, and the sealed connection between the unit and the housing 100 is not limited to the threaded seal described here.

[0057] As a specific embodiment, in order to achieve signal extraction, refer to... Figures 5-7When the lead wire 610 of the thermocouple 600 is led out from inside the housing 100, it first passes through the lead groove 601 in the middle of the bottom recess, and then connects with the lead wire hole 621 located in the center of the second cut 620 on the side wall of the housing, finally leading the lead wire 610 to the outside of the housing 100. In addition, other wiring related to temperature control (such as heating element-related wires) is carried out through a separate heating hole 622 in the second cut 620, and the heating hole 622 is isolated from the lead wire hole 621 to ensure electrical safety and signal stability.

[0058] Furthermore, in one specific embodiment, the three cutouts on the outer peripheral boss 101 of the side wall of the housing 100 are functionally modularly distributed: the first cutout 630 is used for the installation of the lever arm 500 (as described above); the second cutout 620 is used for wiring for temperature sensing and control, and heating (as described above); the third cutout 640 has a threaded handle hole for installing the handle 800 for easy handling. The circumferentially spaced cutouts are designed to facilitate the integration and maintenance of the components, and do not exclude other functionally equivalent design schemes. Of course, the three cutouts are set to facilitate the installation of the above-mentioned device, and other possible designs do not affect the core of the present invention.

[0059] This device constructs a controllable environment through a sealed cavity unit, realizes multi-form friction simulation through a modular friction actuator, ensures friction force testing through an integrated force measurement unit, and monitors real-time temperature through an in-situ temperature sensing unit. Through the coordinated work of key components, it realizes life tests coupled with multiple factors such as different friction forms and temperature changes on a single rack. It can obtain lubricant performance and life data that are closer to actual service behavior with lower cost, fewer oil samples, and shorter cycle.

[0060] As an example, see Figure 10 The device also includes a temperature control mechanism; the temperature control mechanism is any one or a combination of two of the following:

[0061] (1) A temperature control jacket 710 fixed to the outside of the housing 100, the inner wall of the temperature control jacket 710 and the outer wall of the housing 100 form a second sealed cavity 720; the temperature control jacket 710 is provided with a temperature control interface 711 communicating with the second sealed cavity 720.

[0062] (2) A heating device installed on the housing 100.

[0063] For details, please refer to Figure 11A temperature-controlled jacket 710 is fitted and fixed to the outside of the housing 100 and sealed, forming a second sealed cavity 720 surrounding the housing 100 between the inner wall of the temperature-controlled jacket 710 and the outer wall of the housing 100. The temperature-controlled jacket 710 is provided with at least two temperature-controlled interfaces 711, which communicate with the second sealed cavity 720 and are used to introduce a temperature-controlled medium to regulate the temperature within the first sealed cavity 130. Each temperature-controlled interface 711 includes at least one temperature-controlled inlet for the inflow of the temperature-controlled medium and one temperature-controlled outlet for the outflow of the medium, enabling the circulation and temperature transfer of the temperature-controlled medium within the system. Depending on actual needs, hot gas / fluid can be introduced for heating, or cooling water or other media can be introduced for cooling, thereby indirectly regulating the temperature of the first sealed cavity 130 inside the housing 100. This method is suitable for applications requiring high temperature uniformity and stability.

[0064] In another embodiment, a heating device disposed on the housing 100 is also included. See below. Figure 12 and ​ The bottom of the housing 100 is provided with a heating hole 622 for placing heating elements such as heating rods. The heating rods are placed at the bottom of the housing 100 and isolated from the first sealed cavity 130, achieving heating of the internal system through heat conduction. This method has a simple structure and is suitable for applications where heating is the primary function and temperature control accuracy requirements are relatively relaxed. Of course, the installation method and type of the heating device in this invention are not limited to this.

[0065] The above two temperature control methods can be selectively applied individually or in combination, depending on the actual test requirements for temperature control accuracy, heating and cooling rates, and system complexity, in order to achieve flexible and efficient temperature environment simulation.

[0066] As an example, the upconversion unit 200 includes an upper cylindrical boss 210, a main cylinder 220 and a lower cylindrical boss 230 arranged coaxially; the upper cylindrical boss 210 is used to pass through the top cover 120 and has the smallest outer diameter; the main cylinder 220 has the largest outer diameter; and the outer diameter of the lower cylindrical boss 230 is between the two.

[0067] In one specific embodiment, see ​The upper conversion unit 200 comprises three functional parts: an upper cylindrical boss 210 at the top, a main cylinder 220 forming the main outer diameter, and a lower cylindrical boss 230 at the bottom. The upper cylindrical boss 210 is located at the center axial position of the top surface of the main cylinder 220, has the smallest outer diameter, and serves as a drive connection part, passing through the first through hole 140 of the top cover 120 to connect to the rotary drive device (in this embodiment, the main shaft 940 of the testing machine). An annular region is formed between the outer edge of the top surface of the main cylinder 220 and the upper cylindrical boss 210. The lower cylindrical boss 230 is located at the center axial position of the bottom surface of the main cylinder 220, with an outer diameter between the two; and is used to install the upper pressure plate 410 in the subsequent test friction pair 400. It should be understood that the present invention does not limit the specific structural shape of the upper conversion unit 200. Any structural modification that can achieve the same hierarchical connection and installation function falls within the protection scope of this invention.

[0068] As an example, the upconversion unit 200 is provided with axial holes 221, which are uniformly distributed along the circumference of the upconversion unit 200 to agitate the oil and achieve a homogeneous distribution of the lubricant.

[0069] Specifically, the axial holes 221 are located around the periphery of the annular region. The function of the axial holes 221 is to effectively stir the internal oil by generating directional eddies and disturbances in the fluid medium, thereby promoting the temperature equilibrium and homogeneous distribution of the lubricant, avoiding local precipitation or heat accumulation, and improving the thermal management and operational stability of the overall system. As an example, axial holes 221 are also provided in the annular region on the top surface of the main cylinder 220; the number of axial holes 221 is ≥1, preferably 3 to 8, and they are evenly distributed. It can be understood that the number, distribution (e.g., equidistant or non-equidistant), and specific dimensions of the axial holes 221 can be adjusted according to the cavity size, oil viscosity, and stirring requirements. These design variations based on the same stirring principle should all fall within the protection scope of this invention.

[0070] As an example, the friction actuator constitutes an adaptable module that can be replaced as a whole; wherein, the up-conversion unit 200 and the down-conversion unit 300 are connected to the main body of the device through a unified mechanical interface.

[0071] Specifically, the key feature of the aforementioned mechanical structure is that the mechanical interface connecting the upper conversion unit 200 to the drive mechanism of the device body is uniform and standardized in all different types of adapter modules; the mechanical interface connecting the lower conversion unit 300 to the base or fixed part of the device body is also uniform and standardized. This modular design allows for quick replacement of modules containing different friction pairs and corresponding conversion units according to different testing needs, without the need for complex disassembly or adjustment of the device body, thereby achieving flexible conversion of motion modes, including sliding, rolling, and sliding-rolling compound motion, thus ensuring immediate installation and application in terms of accuracy, power transmission, and signal connection.

[0072] It is understood that the adapter module and mechanical interface in this embodiment are only a preferred method for achieving rapid conversion of motion modes. Without departing from the core concept of this invention, the specific implementation of the module, the type (such as flange, snap-fit, quick-lock) and quantity of the interface can be adjusted or reconfigured according to actual needs.

[0073] As an example, the mechanical interface is configured to be detachable, allowing the upper conversion unit 200 to be separated from the top cover 120, and the lower conversion unit 300 to be separated from the bottom of the housing 100.

[0074] For details, please refer to ​ and ​ The detachable connection includes, but is not limited to, one or more combinations of threaded fastening, flange locking, snap-on quick release, or locating pin engagement, to meet the needs of different load accuracy and replacement frequency. In a preferred embodiment, the detachable connection adopts the following structure: the top of the upper conversion unit 200 is provided with a keyway, and a locating key 211 is provided in the keyway. In this embodiment, the locating key 211 is located on the upper cylindrical boss 210 of the upper conversion unit 200, and the power rotation device (testing machine spindle 940) connected to it is provided with a chuck 930 that mates with the locating key 211 for axial clamping and fixing of the upper conversion unit 200, thereby achieving circumferential anti-rotation of both. This structure constitutes a dedicated power interface that can be quickly assembled and disassembled and ensures high coaxiality.

[0075] This design allows for convenient switching between different forms of contact, such as point contact, line contact, and surface contact, on a single test device by quickly replacing the upconversion unit 200, which is adapted to friction pairs with different contact surface shapes (such as spherical, cylindrical, and planar surfaces), greatly expanding the testing range of the device.

[0076] As a specific embodiment, see ​ and ​The downconversion unit 300 also includes a mounting platform 340, which has a positioning hole 310, a second mounting hole 320, and a flow hole 330. The positioning hole 310 is located around the periphery of the mounting platform 340 and extends through it, cooperating with the positioning post 110 at the bottom of the housing 100 to achieve circumferential positioning of the downconversion unit 300. The second mounting hole 320 facilitates the installation and removal of the downconversion unit 300. The flow hole 330 is preferably located in the central area of ​​the mounting platform 340, allowing lubricant to flow during testing and providing a channel for temperature sensing elements such as the thermocouple 600 to directly contact the lubricant for real-time temperature monitoring. Of course, the configuration of the downconversion unit 300 is not limited to this.

[0077] Furthermore, the upper periphery of the mounting platform 340 of the lower conversion unit 300 is provided with a mounting groove 350 to accommodate the lower pressure plate 430 in the subsequent test friction pair 400, and the height of the lower pressure plate 430 is lower than the height of the upper surface of the lower conversion unit 300, so as to achieve a limiting function in the subsequent friction test.

[0078] As an example, the test friction pair 400 is a customized friction pair or a standard bearing friction pair; the standard bearing friction pair is obtained by selecting a standard bearing; the customized friction pair includes an upper pressure plate 410 and a lower pressure plate 430; wherein, the customized friction pair is a slanted roller friction pair or a ring friction pair; the slanted roller friction pair also includes a slanted roller 420 disposed between the upper pressure plate 410 and the lower pressure plate 430.

[0079] Specifically, the standard bearing friction pair is achieved by directly selecting commercially available standard bearings, which features good interchangeability and low cost; the customized friction pair consists of independently designed upper pressure plate 410 and lower pressure plate 430. In this embodiment, the upper pressure plate 410 is a ring structure with a through hole, which is fitted onto the lower cylindrical boss 230 of the upper conversion unit 200; the lower pressure plate 430 is a ring structure with a through hole, which is placed in the mounting groove 350 in the lower conversion unit 300; of course, the shape, material and structure of the upper pressure plate 410 and the lower pressure plate 430 can be designed according to actual test requirements to achieve more complex working condition simulation and testing functions.

[0080] Furthermore, customized friction pairs can be specifically designed as inclined roller friction pairs or annular friction pairs to meet specific test requirements and contact patterns. See also... ​The inclined roller friction pair, in addition to the independently designed upper pressure plate 410 and lower pressure plate 430, also includes a freely rolling inclined roller between them, simulating complex friction behavior through a combination of rolling and sliding. The annular friction pair, on the other hand, consists of an upper pressure plate 410 and a lower pressure plate 430 with concentric annular contact surfaces, suitable for stable and uniform surface contact wear and lubrication testing. Of course, customized friction pairs are not limited to these, and will not be detailed here.

[0081] As an example, the standard bearing is one of radial rolling bearings, thrust rolling bearings, or angular contact rolling bearings.

[0082] Specifically, radial rolling bearings are suitable for simulating operating conditions where radial loads are the primary load, while also taking into account a certain amount of axial loads; examples include deep groove ball bearings. Thrust rolling bearings are specifically designed for test scenarios where thrust loads are applied along the axial direction; examples include thrust ball bearings, thrust tapered roller bearings, thrust cylindrical roller bearings, or thrust self-aligning roller bearings. Angular contact rolling bearings are suitable for precision friction tests where both radial and axial combined loads are applied simultaneously, and precise control of the contact angle and stiffness is required; examples include angular contact ball bearings and tapered roller bearings. This standard bearing type friction pair is achieved by selecting commercially available standard bearings, offering advantages such as good interchangeability, low cost, and ease of replacement. It is suitable for standardized tests with high requirements for test versatility and efficiency. Of course, the aforementioned standard bearings are not limited to these, and will not be elaborated upon here.

[0083] As an example, see ​ The customized friction pair is a slanted roller friction pair, with slanted rollers 420 arranged at intervals through the first mounting holes in the first retainer 421; the first retainer 421 is mounted on a limiting member 422, and the limiting member 422 has a first boss 425 extending radially outward. The first boss 425 is coaxial with the first retainer 421 and has a clearance fit, so that the first retainer 421 can rotate around the limiting member 422; the limiting member 422 is fixed relative to the lower pressure plate 430.

[0084] Specifically, in this embodiment, when the upper pressure plate 410 is subjected to a normal load and rotates relative to the lower pressure plate 430, the inclined roller 420 simultaneously generates a combined rolling and sliding motion between the annular inclined surface between the upper pressure plate 410 and the lower pressure plate 430, thereby generating the frictional torque to be measured; this torque is transmitted to the corresponding force sensor through the lever arm 500, and finally the dynamic test of frictional force or frictional torque is completed.

[0085] Furthermore, in this embodiment, refer to ​The first mounting hole is a circumferentially oriented through hole in the first retainer 421, into which the inclined roller 420 is placed. The limiting member 422 also has a threaded hole 423 for easy removal. Specifically, in this embodiment, the first retainer 421 has a radially inwardly extending second boss 424. The second boss 424 and the first boss 425 are clearance-fitted in the vertical direction, leaving a gap between the first retainer 421 and the lower pressure plate 430, ensuring that the inclined roller 420 can contact the upper pressure plate 410 and the lower pressure plate 430 within this gap. During the subsequent rotation drive of the test friction pair 400, the limiting member 422 and the lower pressure plate 430 remain relatively stationary. Based on the pushing force, the upper pressure plate 410 and the inclined roller 420 (corresponding to the first retainer 421) undergo relative circumferential movement, and the inclined roller 420 (corresponding to the first retainer 421) and the lower pressure plate 430 also undergo relative circumferential movement. The height of the first retainer 421 is higher than the plane of the lower conversion unit 300. In another specific embodiment, the first retainer 421 does not have a second boss 424 extending radially inward, but instead forms a clearance fit with the first boss 425 on the limiting member 422, thereby realizing relative circumferential movement between the inclined roller 420 (and the first retainer 421) and the lower pressure plate 430. It should be noted that the description of the friction pair structure in this embodiment is intended to clearly explain its working principle, and the scope of protection of this invention is not limited to this specific structural form.

[0086] As described above, the device includes a housing, a top cover, and a first sealed cavity. The first sealed cavity houses a modular friction actuator, which consists of an upper conversion unit, a test friction pair, and a lower conversion unit, and can be replaced as a whole through a unified mechanical interface. The upper conversion unit is connected to an external drive, while the lower conversion unit is fixed to the housing. The force measurement unit detects the transmitted frictional force through a lever arm fixed to the housing, and the temperature sensing unit monitors the temperature inside the cavity through a probe. This invention overcomes the shortcomings of traditional lubricant friction testing devices, such as limited functionality, high cost, and difficulty in simulating real-world working conditions. By employing a modular friction actuator that can be replaced as a whole, integrated testing of lubricant friction performance under various contact forms (point, line, surface) and pure sliding, rolling, and sliding-rolling composite motions is achieved.

[0087] Example 2

[0088] This embodiment is based on the application method of Embodiment 1 or other similar multifunctional lubricant friction testing devices. This application method can be used to test different types of lubricants. In this embodiment, the lubricants tested are gear oil A and gear oil B. The steps of the application method for lubricant friction testing are the same. The following description uses the testing of gear oil A as an example to illustrate each step, and each step includes:

[0089] First, based on the target test conditions, select the appropriate test friction pair 400 and the corresponding up-conversion unit 200 and down-conversion unit 300 to construct a specific kinematic pair and loading mechanism.

[0090] Specifically, to improve the efficiency of lubricant life evaluation, this embodiment uses a slanted roller friction pair as an example. The slanted roller friction pair includes a lower pressure plate 430, a slanted roller 420, and a lower pressure plate 430, wherein the slanted roller 420 is disposed between the upper pressure plate 410 and the lower pressure plate 430 via a first retainer 421 in the middle. In this embodiment, before transferring to the test friction pair 400, the test friction pair 400 is weighed, and its mass before the friction test is recorded as M0. Of course, in other embodiments, other friction pairs can be selected for the test friction pair 400.

[0091] Next, the lubricant to be tested is injected into the first sealed cavity 130 of the device. After injecting the lubricant and before sealing the first sealed cavity 130, the test friction pair 400, the upper conversion unit 200 and the lower conversion unit 300 are installed to ensure that each component is in the working position in the lubricant.

[0092] Specifically, in this embodiment, the housing 100 is placed on a horizontal platform. Then, the lower pressure plate 430 is installed in the lower conversion unit 300, and the lower conversion unit 300 is positioned within the inner cavity of the housing 100. Next, the central inclined roller 420 and the first retainer 421 are positioned on the lower pressure plate 430. 10.0g of gear oil A is injected into the inner cavity of the housing 100, ensuring the lubricant level is higher than the surface height of the inclined roller 420. The upper pressure plate 410 is then installed on the upper conversion unit 200, which is placed within the inner cavity of the housing 100. Finally, the top cover 120 is screwed on to complete the assembly of the test device. The bottom of the housing 100 is equipped with a first base ring 900, and the first base ring 900 is provided with a raceway 901; the testing machine base 920 is equipped with a second base ring 910 and a ball 950, the ball 950 is mounted on the second base ring 910 through a second cage 960, and the assembled housing 100 is placed on the second cage 960. The lower end of the rotary drive device (testing machine spindle 940) is equipped with a chuck 930, which holds the upper conversion unit 200.

[0093] Next, set the normal load, initial temperature, and drive speed, start the test, and drive the test friction pair 400 to run.

[0094] Specifically, test parameters such as normal load, initial temperature, and drive speed are set. After startup, the rotary drive device (test machine spindle 940) drives the upper conversion unit 200 and the upper pressure plate 410 mounted on it to rotate, causing the test friction pair 400 to move relative to each other under lubrication conditions. Specifically, sliding and rolling compound friction occurs between the upper pressure plate 410, the lower pressure plate 430, and the inclined roller 420.

[0095] As a specific embodiment, the test parameters are set as follows: the normal load is 2200N; the initial temperature is room temperature, and the heat is dissipated naturally during the test. The spindle speed of the testing machine 940 (rotary drive device) is 500rpm to 3000rpm, increasing in increments of 500rpm, for a total of 6 groups; the friction pair rotates a total of 10000 revolutions at each speed group. After each test group is completed, a 10-minute interval is used for cooling before the next test group is conducted.

[0096] Next, during the experiment, the frictional force or frictional torque measured by the force measurement unit and the lubricant temperature measured by the temperature sensing unit were monitored and recorded in real time.

[0097] Specifically, during the test run, the system performs synchronous data acquisition. First, mechanical data is acquired: the frictional torque generated by the test friction pair 400 is transmitted through the housing 100 to the lever arm 500, and measured in real time by an external force sensor. Second, temperature data is acquired: a thermocouple 600 extends into the first sealed cavity 130 to monitor the lubricant temperature in real time. The acquired real-time data is transmitted to an external receiving device, processed, and can be used to plot friction curves, evaluate the evolution of lubricant performance, and analyze the influence of temperature on the rheological properties and film-forming ability of the lubricant, thus providing a basis for performance comparison and failure mechanism research.

[0098] Next, after the experiment, the lubricant was collected and analyzed, the friction pair 400 was tested and analyzed, and the lubricating performance and life of the lubricant were comprehensively judged.

[0099] Specifically, after the test, the height of the testing machine base 920 can be lowered to separate the upper conversion unit 200 from the chuck 930, and then the entire testing device can be removed. After removing the top cover 120, the components inside the housing 100 can be removed one by one.

[0100] First, the lubricant to be tested was collected and sealed within the first sealed cavity. Its performance degradation and compositional changes after use were systematically evaluated using physicochemical analysis methods such as viscosity, acid value, spectral analysis, and ferrography. Then, the test friction pair 400 (including the lower pressure plate 430, skew roller 420, and upper pressure plate 410) was removed, cleaned, dried, and weighed after testing (M1). Macroscopic morphology observation, roughness measurement, and microscopic morphology analysis (such as SEM / EDS) were performed on its surface to quantitatively obtain information on wear, damage mode, and material transfer. Finally, by combining the friction force-temperature curves recorded during the test, the lubricant analysis results, and the mass loss and surface morphology data of the friction pair, a systematic evaluation of the lubricant's comprehensive lubrication performance (such as friction reduction, wear resistance, and load-bearing capacity) and its service life under simulated working conditions can be made.

[0101] The lubrication performance and lifespan of the two lubricants were evaluated by conducting friction tests on gear oil A and gear oil B respectively. ​ and ​ The test results show the friction coefficient and temperature change curves of different oils during the experiment. It can be seen that the friction force and lubricating oil temperature rise obtained using the test apparatus of this invention are both lower for gear oil B than for gear oil A. Observation of the appearance of the test friction pair 400 also shows that the appearance of gear oil B after the test is better than that of gear oil A, and the surface wear of the friction pair after the test of gear oil B is less than that after the test of gear oil A. Table 1 below shows the physicochemical properties, elemental changes, and weight loss of the friction pair after the test. It can be seen that after 2 hours of friction testing, the physicochemical properties and iron content of the oil changed significantly, and the weight loss of the friction pair also showed significant differences, all of which are correlated with the actual application effect of the oil. Gear oil A has a longer service life than gear oil B under the same conditions. The test process in this embodiment explains that this invention can achieve simultaneous testing of oil lubrication performance and service life.

[0102] Table 1

[0103]

[0104] In another specific embodiment, to evaluate the performance of the lubricant under more complex contact conditions, the test friction pair 400 is replaced with an 81108M cylindrical roller thrust bearing. Correspondingly, the upper conversion unit 200 and the lower conversion unit 300 are also replaced with structures matching the dimensions of the cylindrical roller thrust bearing, while the assembly method remains unchanged. A cross-sectional view after assembly is shown below. ​ As shown.

[0105] This embodiment was used to conduct a comparative test on gear oils C and D. The load was set at 8000 N, the speed at 2000 rpm, and the starting temperature was room temperature. During the test, the temperature was controlled by jacket water circulation, and the test was conducted continuously for 22 hours. After the test, the comparison results showed that the bearing surface using gear oil C had no obvious wear marks, and the oil appearance was relatively clear, indicating that it had an excellent protective effect on the friction pair; while the bearing surface using gear oil D showed obvious pits, and the oil condition was also abnormal, indicating that its anti-wear and fatigue performance was insufficient.

[0106] As can be seen from the above comparative test results, the test method of the present invention can effectively simulate actual high-load working conditions and has a significant ability to distinguish the protective performance of different lubricating oils, thus verifying the effectiveness and applicability of the method in evaluating the comprehensive performance of lubricants.

[0107] In summary, this invention discloses a multifunctional lubricant friction testing device and method. The device includes a housing, a top cover, and a first sealed cavity. A modular friction actuator is housed within the first sealed cavity, consisting of an upper conversion unit, a test friction pair, and a lower conversion unit, all of which can be replaced as a whole through a unified mechanical interface. The upper conversion unit is connected to an external drive, while the lower conversion unit is fixed to the housing. A force measurement unit detects the transmitted frictional force through a lever arm fixed to the housing, and a temperature sensing unit monitors the temperature inside the cavity through a probe. This invention overcomes the shortcomings of traditional lubricant friction testing devices, such as limited functionality, high cost, and difficulty in simulating real-world working conditions. By employing a modular friction actuator that can be replaced as a whole, it achieves integrated testing of lubricant friction performance under various contact forms (point, line, surface) and pure sliding, rolling, and sliding-rolling composite motions. Simultaneously, through high-precision force and temperature monitoring and near-real-world working condition simulation, it provides a reliable and efficient experimental method for lubricant performance comparison, failure analysis, and life prediction, possessing strong engineering practicality and scientific research value. This design significantly improves testing efficiency, reduces the cost of replacing the entire equipment, and allows for flexible modular combinations to make testing conditions more closely resemble actual complex working conditions. This provides a more reliable, economical, and efficient experimental method for evaluating lubricant performance and predicting its lifespan. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0108] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A multi-functional lubricant friction test apparatus characterized by, It comprises: a shell; a top cover, which forms a first sealed cavity with the shell; a friction execution mechanism, which is accommodated in the first sealed cavity, the friction execution mechanism comprising an upper conversion unit, a test friction pair and a lower conversion unit; the test friction pair is arranged between the upper conversion unit and the lower conversion unit; the upper conversion unit has an upwardly extending driving connection part which passes through a first through hole arranged on the top cover and is used for connecting an external rotary driving device; the upper conversion unit is detachably connected with the top cover; wherein the lower conversion unit is mounted on the bottom of the shell; a force measuring unit, which comprises a force arm rod, a first end of the force arm rod being fixed to the outer wall of the shell and being used for detecting the friction force or friction torque generated by the test friction pair and transmitted through the shell; a temperature sensing unit, which extends into the first sealed cavity through a second through hole arranged on the shell and is sealingly connected with the shell.

2. The multi-functional lubricant friction test apparatus according to claim 1, characterized by, It also comprises a temperature control mechanism; the temperature control mechanism is any one or a combination of the following: (1) a temperature control jacket fixed to the outside of the shell, a second sealed cavity being formed between the inner wall of the temperature control jacket and the outer wall of the shell; a temperature control interface is arranged on the temperature control jacket and communicates with the second sealed cavity; (2) a heating device arranged on the shell.

3. The multi-functional lubricant friction test apparatus according to claim 1, characterized by: The upper conversion unit comprises coaxially arranged upper cylindrical bosses, a main body cylinder and lower cylindrical bosses; the upper cylindrical bosses are used for passing through the top cover and have the smallest outer diameter; the main body cylinder has the largest outer diameter; the outer diameter of the lower cylindrical bosses is between the two.

4. The multi-functional lubricant friction test apparatus according to claim 3, characterized by: The upper conversion unit is also provided with axial holes which are uniformly distributed along the circumference of the upper conversion unit.

5. The multi-functional lubricant tribological test device of claim 1 or 3, wherein: The friction execution mechanism constitutes an overall replaceable adaptive module; wherein the upper conversion unit and the lower conversion unit can be connected with corresponding matching interfaces on the main body of the device through a unified mechanical interface.

6. The multi-functional lubricant friction test apparatus according to claim 5, characterized by: The mechanical interface is a detachable interface, so that the upper conversion unit and the top cover, and the lower conversion unit and the bottom of the shell can be separated.

7. The multi-functional lubricant friction test apparatus of claim 1, wherein: The test friction pair is a customized friction pair or a standard bearing type friction pair; the customized friction pair comprises upper and lower pressure plates; wherein the customized friction pair is a skew roller type friction pair or a circular ring type friction pair; the skew roller type friction pair further comprises skew rollers arranged between the upper and lower pressure plates.

8. The multi-functional lubricant friction test apparatus according to claim 7, characterized by: The standard bearing is one of a radial rolling bearing, a thrust rolling bearing or an angular contact rolling bearing.

9. The multi-functional lubricant friction test apparatus of claim 7, wherein: The customized friction pair is a skew roller type friction pair, the skew rollers are arranged at intervals through first mounting holes in a first retainer; the first retainer is arranged on a limiting piece, the limiting piece is provided with a first boss extending radially outward, the first boss is coaxial with the first retainer and is in clearance fit, so that the first retainer can rotate around the limiting piece; the limiting piece is fixed relative to the lower pressure plate.

10. The multifunctional lubricant friction tester application according to any one of claims 1-9, characterized in that: According to the target test working condition, a suitable test friction pair and corresponding upper and lower conversion units are selected; A lubricant to be tested is injected into a sealed chamber of the device, and after the injection of the lubricant, the installation of the test friction pair and the upper and lower conversion units is completed before the chamber is closed; A normal load, an initial temperature, and a driving rotating speed are set, the test is started, and the test friction pair is driven to operate; During the test, the friction force or torque measured by the force measuring unit and the lubricant temperature measured by the temperature sensing unit are monitored and recorded in real time; After the test, the lubricant is collected and analyzed, the test friction pair is processed and analyzed, and the lubricating performance and service life of the lubricant are comprehensively judged.

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