Motor bearing conductive grease service characteristic measuring device

Abstract

The utility model belongs to the technical field of lubrication experiment equipment, and relates to a motor bearing conductive grease service characteristic measuring device, the main body structure comprises a loading unit and a measuring unit connected with the loading unit, the main body structure of the loading unit comprises a tension and pressure sensor, a loading bolt and a ceramic cushion block arranged between the tension and pressure sensor and the loading bolt; the main body structure of the measuring unit comprises a main shaft, a shaft collar, an auxiliary bearing, a to-be-measured bearing and a needle bearing, the rotating speed of a thrust roller bearing, the torque of the main shaft and an applied load are connected in series through a torque sensor and a pull pressure sensor, and the load of the to-be-measured bearing is measured synchronously. A temperature sensor is adopted to measure the temperature of a to-be-measured bearing in actual work in real time, the state of conductive lubricating grease in the experiment process is observed in real time through an observation window, the physical and chemical properties of the conductive lubricating grease are analyzed, the service characteristics of the conductive lubricating grease are evaluated, and the relation between breakdown voltage and load, torque, rotating speed and temperature is established. And reference data is provided for lubricating grease performance optimization.

Description

Technical field:

[0001] The utility model belongs to the technical field of lubrication experimental equipment, and specifically relates to a service characteristic measuring device for conductive grease of motor bearings, which can test the conductive grease performance of motor thrust bearings running under relatively large load conditions. Background technology:

[0002] The development of power conversion technology has provided a more comprehensive solution for industrial control, further satisfying the conversion requirements of three-phase AC power in production and application. For example, the high-frequency switching of PWM inverters has greatly improved the speed regulation performance of AC motors. Inverters integrate the current generated by generators under different operating conditions into the power grid's permitted energy. However, the in-depth application of power conversion technology in the mechanical field has led to the occurrence of electrolytic corrosion in the rolling bearings of power machinery.

[0003] Electrocorrosion in rolling bearings is caused by high-frequency shaft currents. During PWM modulation, the switching is asynchronous, generating asymmetric high-order harmonics. This causes the neutral-point voltage of the motor winding to vary from zero, creating a common-mode voltage. Under this high-frequency alternating voltage, the tiny capacitors within the motor and the capacitance generated by the oil film during high-speed operation of the rolling bearing undergo a charging and discharging effect, generating a current and a potential difference between the two terminals. As the oil film builds, the voltage continuously increases. When the voltage exceeds the breakdown voltage of the oil film, it breaks down, instantly generating a high current that burns and bonds the rolling element surfaces. Repeatedly, this process tears the bearing surface material. Furthermore, the high temperature alters the metallographic structure of the raceway, reducing its hardness and causing grease deterioration. This can shorten the bearing life at best, or even cause the bearing to seize. Since rolling bearings are essential components of mechanical equipment, their overall performance is closely linked to their performance. Therefore, it is necessary to suppress electrocorrosion in rolling bearings.

[0004] To mitigate or prevent galvanic failure, rolling bearing outer rings are typically insulated or a conductive lubricant is used. The former requires specialized bearings, while the latter reduces the grease's breakdown voltage and is relatively inexpensive. Conductive greases are lubricants that incorporate abrasive conductive materials to reduce the oil film's breakdown voltage while ensuring lubrication performance. Because the oil film's breakdown voltage is dependent on operating speed, load, and temperature, the dynamic characteristics of conductive greases in rolling bearings are studied using a ball-on-disc dual-drive test bench to simulate the contact and operation of rolling elements and raceways. Conductive carbon brushes are used to apply an electric field to the rolling elements and raceways, measuring their impedance and evaluating the grease's properties. Alternatively, the rolling bearing is electrically conductive, and a voltmeter and ammeter are used to measure the power supply voltage and circuit current. The oil film's resistivity is then calculated to evaluate the grease's performance. Alternatively, an insulated bolt is used on a full-bearing testing machine to apply an electric field, collecting real-time data such as temperature, torque, and electrical parameters to evaluate the grease's properties. For example, a bearing testing device disclosed in Chinese patent 202410985500.9 (Guanxian Tianben Bearing Co., Ltd.) includes a mounting frame and a connecting plate fixedly connected to the mounting frame, a support plate for supporting a flexible bearing is rotatably connected to the mounting frame, the support plate is elliptical, the support plate is located in the middle of the connecting plate, a plurality of supporting hydraulic cylinders are fixedly connected to the connecting plate, and the plurality of supporting hydraulic cylinders are circumferentially distributed toward the support plate, the supporting hydraulic cylinder is used to push the flexible bearing close to the outer wall of the support plate, a needle valve is slidably connected to the return liquid port of the supporting hydraulic cylinder, and a three-way valve is fixedly connected to the connection between the return liquid port of the supporting hydraulic cylinder and the needle valve. When the flexible bearing is clamped, the three-way valve introduces hydraulic medium into the supporting hydraulic cylinder, and a clamping mechanism for clamping the flexible bearing is provided on the mounting frame, the clamping mechanism includes a clamping cylinder fixedly connected to the support plate, and the clamping cylinder The cam is connected with the hydraulic cylinder to move the hydraulic cylinder to move along the hydraulic cylinder to move along the hydraulic cylinder to move along the hydraulic cylinder to move along the hydraulic cylinder to move along the hydraulic cylinder to move along the hydraulic cylinder to move along the hydraulic cylinder to move along the hydraulic cylinder to move along theA bearing test device (Xi'an Aerospace Power Institute) disclosed by Chinese patent 202410682589.1 comprises: an auxiliary shaft and a swing shaft arranged in parallel; two lateral mounting plates arranged in parallel, the lateral mounting plates are provided with first mounting holes and second mounting holes, the auxiliary shaft passes through the first mounting holes of the two lateral mounting plates in sequence, and the swing shaft passes through the second mounting holes of the two lateral mounting plates in sequence; two first bearings and a first axial limiting piece, the two first bearings are sleeved on the auxiliary shaft and are respectively located in the first mounting holes of the two lateral mounting plates, and the first axial limiting piece is used for limiting axial displacement of the first bearing; a radial pull plate, the radial pull plate is provided with a third mounting hole, the auxiliary shaft passes through the third mounting hole, and the radial pull plate is located between the two lateral mounting plates; two test bearings can be sleeved on the swing shaft and are respectively located in the second mounting holes of the two lateral mounting plates, the bearing test device further comprises a second axial limiting piece, the second axial limiting piece is used for limiting axial displacement of the test bearing; an intermediate mounting plate, the intermediate mounting plate is provided with a fourth mounting hole, the swing shaft passes through the fourth mounting hole, the intermediate mounting plate is rotationally connected with the swing shaft, the intermediate mounting plate is located between the two lateral mounting plates, the swing shaft comprises a first segment, a second segment and a third segment connected in sequence, the diameters of the first segment and the third segment are smaller than the diameter of the second segment, the two test bearings are respectively connected with the first segment and the third segment, and the intermediate mounting plate is rotationally connected with the second segment; and a load actuating assembly, the load actuating assembly can apply radial load, axial load and / or swing load to the second bearing.The motor bearing test device (China Railway Stock Company Limited) disclosed by Chinese patent 202311810784.X comprises a test bench, a rotating shaft, a loaded bearing and a radial loading block, the inner ring of the loaded bearing is matched with the rotating shaft, and the outer ring of the loaded bearing is matched with the inner ring of the radial loading block; further comprising: a mounting seat installed on the test bench and providing support for the rotating shaft; two slide rods installed on the mounting seat and parallel to the rotating shaft; a swing prevention structure respectively sleeved on the two slide rods and capable of sliding left and right; the swing prevention structure comprises a swing prevention directional piece capable of being adjusted in an extendible manner, the swing prevention directional piece is in abutment with the surface of the radial loading block, and the swing prevention structure further comprises a swing prevention block and a positioning bolt; the swing prevention block is provided with a through hole and is sleeved on the slide rod, the end of the swing prevention block away from the radial loading block is provided with a first screw hole, the first screw hole is matched with the positioning bolt, the end of the positioning bolt is in abutment with the surface of the slide rod and is used for fixing the position of the swing prevention block on the slide rod, the swing prevention directional piece comprises a swing prevention pin head screw rod and a nut; the end of the swing prevention pin head screw rod is in abutment with the surface of the radial loading block, the surface of the radial loading block is provided with a blind hole, the other end of the swing prevention pin head screw rod is in abutment with the bottom of the blind hole, the central axis of the swing prevention pin head screw rod is perpendicular to the central axis of the rotating shaft, the central axes of the two swing prevention pin head screw rods are both intersected with the central axis of the rotating shaft and form an included angle, the included angle is not 180° or 360°, the slide rods are located above the two sides of the radial loading block respectively, the outer surface of the slide rod is provided with a cutting surface and is in abutment with the end of the positioning bolt, the mounting seat is provided with a through hole, the two ends of the slide rod are provided with threads, the two ends of the slide rod pass through the through hole and are fixed on the mounting seat by the nut, the gap between the side surface of the swing prevention pin head screw rod and the side surface of the blind hole of the radial loading block is greater than the axial play of the positioning bearing on the test shaft and is smaller than the axial gap of the labyrinth seal of the loaded bearing, the width of the bottom of the blind hole is smaller than the diameter of the tail width of the swing prevention pin head screw rod, and a certain gap is reserved between the tail end surface of the swing prevention pin head screw rod and the bottom of the blind hole. The above device or method provides a certain reference for the performance measurement technology of conductive grease, but there are still some deficiencies. At present, the measurement and evaluation of the service characteristics of conductive grease can only be carried out through electrical parameters under small load. Therefore, it is necessary to establish an experimental device which can work reliably under high load conditions and simulate more working conditions to study the performance of conductive grease. SUMMARY

[0005] The utility model discloses a kind of motor bearing conductive grease service characteristics measuring devices to overcome the defects existing in prior art, real-time measurement rolling bearing temperature in actual work, evaluate the service characteristics of conductive grease, provide reference for lubricating grease performance optimization.

[0006] The main body structure of the motor bearing conductive grease service characteristics measuring device of the utility model comprises a loading unit and a measuring unit connected therewith;

[0007] The main structure of the loading unit comprises a tensile and compressive force sensor and a loading bolt, and a ceramic pad is arranged between the two;

[0008] The main structure of the measuring unit comprises a main shaft, a collar arranged on the main shaft, an auxiliary bearing, a bearing to be measured and a needle bearing;

[0009] Specifically, the loading unit and the measuring unit are connected with each other and fixed on an operation table provided with support screws at the bottom, the measuring unit is connected with the motor through a transmission mechanism, an insulating coupling and a torque sensor are arranged between the measuring unit and the transmission mechanism, and the measuring unit is connected with an electrical unit and a temperature sensor respectively;

[0010] The main structure of the loading unit further comprises a loading sleeve, a loading end cover, an insulating sleeve, a sensor support and a screw, the inside of the loading sleeve provided with the loading end cover at the end is provided with the insulating sleeve, the inside of the insulating sleeve is provided with two sensor supports, the tensile and compressive force sensor is arranged between the two sensor supports, and the ceramic pad is connected with one of the sensor supports and in contact with the loading bolt penetrating through the loading end cover;

[0011] The main structure of the measuring unit further comprises a measuring sleeve, a support stand, a bearing seat, an insulating nylon sleeve, an insulating nylon block and an oil seal, the end of the measuring sleeve is provided with the support stand, the inside of the measuring sleeve is provided with two bearing seats, the main shaft is arranged on the bearing seats and is provided with the collar, the auxiliary bearing and the bearing to be measured between the main shaft and the bearing seats, in addition, the insulating nylon sleeve is arranged between the measuring sleeve and the bearing seats, the insulating nylon block is arranged between the support stand and the bearing seats, the oil seal is arranged between the main shaft and the support stand, and the needle bearing is arranged between the main shaft and the insulating nylon sleeve;

[0012] The outside of the loading unit and the measuring unit is connected through the loading sleeve and the measuring sleeve, and the inside is connected through the sensor support and the bearing seat, a disc spring is arranged between the sensor support and the bearing seat, an observation window is arranged on the measuring sleeve, so that the experiment can be observed through optical technology, the motor drives the main shaft in a belt transmission mode, the conductive carbon brush is connected with the main shaft as a negative electrode, the electric signal is transmitted from the power supply to the bearing seat through a wire and sequentially passes through the bearing to be measured, the main shaft and the conductive carbon brush, and then returns to the power supply through the current plug after adjusting the impedance to form a loop.

[0013] The operation table is used to fix the loading unit, the measuring unit, the transmission mechanism, the motor and the temperature sensor;

[0014] The support screws are used to support the operation table and can also adjust the position of the operation table;

[0015] The loading unit provides pre-tightening and axial load for the bearing to be measured;

[0016] The measuring unit provides an insulated shaft system for the bearing to be measured;

[0017] The transmission mechanism adopts belt drive;

[0018] The insulating coupling is used to connect the measuring unit and the torque sensor in series to transmit the torque between the two. At the same time, it provides insulation conditions for the measuring unit and electrically isolates the measuring unit and the torque sensor.

[0019] The torque sensor measures the torque and speed of the bearing to be tested in real time, and monitors the friction torque of the auxiliary bearing and the bearing to be tested;

[0020] The temperature sensor is placed against the outer ring of the bearing to be tested, and measures the temperature and temperature rise of the bearing under different working conditions in real time;

[0021] A support adjustment assembly is also provided at the bottom of the loading sleeve;

[0022] The ceramic pad is fixed to the sensor bracket by screws. The axial load of the loading bolt is transmitted to the sensor bracket through the ceramic pad. The axial load is measured by the tension and pressure sensor and loaded by the disc spring. The load is transmitted from the bearing seat to the auxiliary bearing, and then to the bearing to be tested through the shaft collar. Finally, it is unloaded by the nylon insulating block.

[0023] The insulating sleeve is made of high-hardness nylon insulating material between the measuring sleeve and the bearing seat. A vertical groove is provided on the insulating sleeve to facilitate circumferential positioning of the measuring sleeve and the bearing seat using a flat key method.

[0024] The insulating nylon sleeve has a supporting function and an axial vertical groove is provided on the outer surface to facilitate axial positioning through a flat key and to isolate the measuring sleeve from the bearing seat to achieve insulation.

[0025] The main shaft is supported by an auxiliary bearing, a bearing to be tested, and a needle roller bearing. The auxiliary bearing is a thrust roller bearing used to transmit axial loads. The needle roller bearing is located at the maximum diameter of the main shaft and is used for support during assembly to prevent the main shaft from deviating due to gravity.

[0026] The oil seal prevents grease leakage and prevents impurities from entering the measuring sleeve.

[0027] Compared with the prior art, the utility model studies the electrocorrosion of rolling bearings under high-load conditions, connects the rotational speed of the thrust roller bearing, the torque of the main shaft, and the applied load in series through a torque sensor and a tension and pressure sensor, and synchronously measures the load of the bearing to be tested, adopts a temperature sensor to measure the temperature of the bearing to be tested in real time during actual work, observes the state of the conductive grease in real time during the experiment through an observation window, analyzes the physical and chemical properties of the conductive grease, evaluates the service characteristics of the conductive grease, establishes the relationship between the breakdown voltage and the load, torque, rotational speed, and temperature, and provides a reference for optimizing the grease performance; the utility model has a simple structure, high rigidity, and is easy to assemble, and can simultaneously measure the load, torque, rotational speed, and temperature of the bearing to be tested, and observe the state of the conductive grease in real time, so as to conduct a multi-faceted analysis of the experimental results. Description of the drawings:

[0028] Figure 1 It is a schematic diagram of the main structure of the utility model.

[0029] Figure 2 It is a schematic cross-sectional view of the local structure of the present invention.

[0030] Figure 3 This is a structural diagram of the thrust roller bearing involved in the utility model.

[0031] Figure 4 This is a structural diagram of the Z-direction adjustment mechanism involved in the present utility model.

[0032] Figure 5 This is a structural diagram of the electrical unit involved in the present utility model. Specific implementation method:

[0033] Example 1:

[0034] The main structure of the motor bearing conductive grease service characteristics measuring device involved in this embodiment is as follows: Figure 1-Figure 2 As shown, it includes an operating table 1, support screws 2, a loading unit 3, a measuring unit 4, a transmission mechanism 5, a motor 6, an insulating coupling 7, a torque sensor 8, an electrical unit 9 and a temperature sensor 10; support screws 2 are provided at the four corners of the bottom of the operating table 1, and a loading unit 3 is provided on the top surface. The loading unit 3 is connected to the measuring unit 4, and the measuring unit 4 is connected to the motor 6 through the transmission mechanism 5. An insulating coupling 7 and a torque sensor 8 are provided between the measuring unit 4 and the transmission mechanism 5. The measuring unit 4 is also connected to the electrical unit 9 and the temperature sensor 10 respectively.

[0035] The main structure of the loading unit 3 includes a loading sleeve 30, a loading end cover 31, an insulating sleeve 32, a sensor bracket 33, a tension and pressure sensor 34, a screw 35, a ceramic pad 36 and a loading bolt 37. The loading sleeve 30 with a cylindrical hollow structure is provided with a loading end cover 31 at the left end, and an insulating sleeve 32 is provided inside. Sensor brackets 33 are provided at both ends of the insulating sleeve 32. A tension and pressure sensor 34 is provided between the sensor brackets 33. The sensor bracket 33 on the left is connected to the ceramic pad 36 by a screw 35. The ceramic pad 36 is in contact with the loading bolt 37 that passes through the loading end cover 31.

[0036] The main structure of the measuring unit 4 includes a measuring sleeve 40, a supporting plate 41, a bearing seat 42, an insulating nylon sleeve 43, an insulating nylon block 44, a main shaft 45, an oil seal 46, a collar 47, an auxiliary bearing 48, a bearing to be measured 49 and a needle roller bearing 50; the right end of the cylindrical hollow structure measuring sleeve 40 is provided with a supporting plate 41, and both ends of the interior are provided with a bearing seat 42, and an insulating nylon sleeve 43 is provided between the measuring sleeve 40 and the bearing seat 42. An insulating nylon block 44 is arranged between the supporting plate 41 and the bearing seat 42, a main shaft 45 is arranged on the bearing seat 42, an oil seal 46 is arranged between the main shaft 45 and the supporting plate 41, a shaft ring 47 and an auxiliary bearing 48 are arranged between the main shaft 45 and the bearing seat 42 on the left, a shaft ring 47 and a bearing to be measured 49 are arranged between the main shaft 45 and the bearing seat 42 on the right, and a needle roller bearing 50 is arranged between the main shaft 45 and the insulating nylon sleeve 43. In addition, an observation window 410 is arranged on the measuring sleeve 40.

[0037] One end of the bearing seat 42 involved in this embodiment extends into the loading sleeve 30 and is clamped into the groove of the sensor bracket 33;

[0038] The auxiliary bearing 48 and the bearing to be tested 49 are both thrust roller bearings with separate structures, such as Figure 3 As shown, it is composed of a shaft ring 481, a seat ring 482, a roller 491 and a retaining frame 492. The inner surface of the shaft ring 481 contacts and cooperates with the surface of the main shaft 45, and the inner surface of the seat ring 482 is separated from the surface of the main shaft 45.

[0039] The electrical unit 9 involved in this embodiment includes a conductive carbon brush 901 and a current plug 902. The conductive carbon brush 901 is set on the main shaft 45. The current plug 902 passes through the supporting plate 41, the insulating nylon block 44 and the bearing seat 42 in sequence and is connected to the bearing 49 to be tested.

[0040] The operating process of the motor bearing conductive grease service characteristic measurement device involved in this embodiment is as follows:

[0041] 1) Cleaning

[0042] First, use a brush or cloth dipped in petroleum ether to clean the old lubricant in the auxiliary bearing 48 and the bearing to be tested 49. Try not to rotate the auxiliary bearing 48 and the bearing to be tested 49 during cleaning to prevent impurities from falling into them.

[0043] Then, clean the auxiliary bearing 48 and the bearing to be tested 49 again with anhydrous ethanol, and wipe them dry with a clean soft cloth. Do not touch the auxiliary bearing 48 and the bearing to be tested 49 with your hands to prevent sweat from corroding the auxiliary bearing 48 and the bearing to be tested 49.

[0044] Finally, place the auxiliary bearing 48 and the bearing to be tested 49 on a clean paper and check whether there are any problems in preparation for subsequent assembly;

[0045] 2) Installation

[0046] First, adjust the level of the operating table 1 to the set requirement using the support screws 2, install the transmission mechanism 5 and the motor 6 on the operating table 1, and adjust the transmission mechanism 5 so that the wrap angle of the small pulley is greater than 120°;

[0047] Next, install the insulating coupling 7, torque sensor 8, support plate 41, and fasteners in sequence. Use the flat key to position the loading sleeve 30 and measuring sleeve 40 and assemble them. Then, assemble the main shaft 45, collar 47, auxiliary bearing 48, bearing to be measured 49, and needle bearing 50 in sequence. Important mating surfaces must not be scratched during assembly. Install the insulating nylon block 44 onto the support plate 41. Fasten the main shaft 45 and measuring sleeve 40 to the support plate 41 with bolts.

[0048] Next, install the disc spring 100 on the boss of the left bearing seat 42, install the sensor bracket 33, the tension and pressure sensor 34, and the ceramic spacer 36 in sequence, and fix the ceramic spacer 36 to the sensor bracket 33 with screws 35;

[0049] Then, adjust the relative position of the loading sleeve 30, turn on the tension and pressure sensor 34, check whether the reading is normal, connect the loading sleeve 30 and the measuring sleeve 40 with bolts, fasten the loading end cover 31 to the loading sleeve 30 with bolts, and install the loading bolts 37.

[0050] Finally, adjust the loading unit 3 and preload the measuring unit 4 so that the inner and outer rings of the bearing 49 to be tested are in the set positions, and install the observation window;

[0051] 3) Detection

[0052] Use a multimeter to measure the impedance of the bearing 49 to be tested and determine whether it is normal. If not, adjust the preload of the bearing 49 to be tested and check whether the power is turned on.

[0053] 4) Debugging

[0054] Connect the measuring unit 4 to the transmission mechanism 5 via the insulating coupling 7 and the torque sensor 8, and adjust the operating table 1 so that its axis is at the set position;

[0055] Turn on the torque sensor 8 and the temperature sensor 10 and check whether the readings are normal;

[0056] Debugging the observation device until the bearing 49 to be tested can be clearly observed;

[0057] 5) Run

[0058] Start the motor 6, monitor the torque and speed through the torque sensor 8, run it at a low power (please limit the range value) for a set time period, monitor the temperature through the temperature sensor 10, and make the lubricant of the bearing 49 to be tested reach the working state;

[0059] 6) Measurement

[0060] Open the tension and pressure sensor 34 and apply a set load. The load is transmitted to the tension and pressure sensor 34 for monitoring via the loading bolt 37, the ceramic spacer 36, and the screw 35. The load is then applied to the bearing seat 42 via the disc spring 100, thereby loading the bearing 49 to be tested. When the reading of the tension and pressure sensor 34 reaches the set value, adjust the motor 6 so that its speed meets the test requirements, apply power, and display and record the measured data on the oscilloscope. Gradually adjust the power supply voltage according to the measurement requirements and record the data.

[0061] 7) Analysis

[0062] Save the measurement data, record the temperature, speed, load and voltage data respectively, and draw graphs to establish the relationship curve between working parameters and voltage, analyze the mechanism, and evaluate the service characteristics of the conductive grease;

[0063] 8) Replacement

[0064] First, stop the motor 6, turn off the power supply, and unload the old bearing 49 to be tested;

[0065] Then, install the new bearing 49 to be tested on the main shaft 45, and use a syringe to evenly fill the space between the rolling element and the bearing race with grease;

[0066] Finally, the collar 47, the auxiliary bearing 48 and the needle bearing 50 are reinstalled and the measurement is performed again.

[0067] Example 2:

[0068] In order to ensure the operating stiffness of the measuring unit 4 and reduce or eliminate the overturning moment of the bolts at the connection between the measuring sleeve 40 and the supporting plate 41 caused by the cantilever, a Z-direction adjustment mechanism is provided at the bottom of the measuring unit 4 on the operating table 1. Figure 4 As shown, an I-shaped support base 500 is provided on the operating table 1 , a support slider 600 is provided at the bottom of the measuring sleeve 40 , and the support base 500 and the support slider 600 are connected by an adjusting screw 700 .

Claims

1. A device for measuring the service characteristics of conductive grease for motor bearings, characterized in that: The main structure includes a loading unit and a measuring unit connected thereto; the main structure of the loading unit includes a tension and pressure sensor, a loading bolt, and a ceramic pad arranged between the two; the main structure of the measuring unit includes a main shaft and a shaft ring, an auxiliary bearing, a bearing to be measured, and a needle roller bearing arranged thereon.

2. The motor bearing conductive grease service characteristics measuring device according to claim 1, characterized in that: The loading unit and the measuring unit are connected to each other and fixed on an operating table with support screws at the bottom. The measuring unit is connected to the motor through a transmission mechanism. An insulating coupling and a torque sensor are provided between the measuring unit and the transmission mechanism. The measuring unit is also connected to the electrical unit and the temperature sensor respectively.

3. The motor bearing conductive grease service characteristics measuring device according to claim 1 or 2, characterized in that: The main structure of the loading unit also includes a loading sleeve, a loading end cover, an insulating sleeve, a sensor bracket and a screw. The loading sleeve with a loading end cover at the end is provided with an insulating sleeve inside, and two sensor brackets are provided inside the insulating sleeve. The tensile and pressure sensors are arranged between the sensor brackets. The ceramic pad is connected to a sensor bracket and contacts with the loading bolt passing through the loading end cover.

4. The device for measuring the service characteristics of conductive grease for motor bearings according to claim 3, characterized in that: The main structure of the measuring unit also includes a measuring sleeve, a supporting plate, a bearing seat, an insulating nylon sleeve, an insulating nylon block and an oil seal. A supporting plate is provided at the end of the measuring sleeve, and two bearing seats are provided inside. The main shaft is provided on the bearing seat, and a shaft ring, an auxiliary bearing and a bearing to be measured are provided between it.

5. The motor bearing conductive grease service characteristics measuring device according to claim 4, characterized in that: An insulating nylon sleeve is provided between the measuring sleeve and the bearing seat, an insulating nylon block is provided between the supporting vertical plate and the bearing seat, an oil seal is provided between the main shaft and the supporting vertical plate, and a needle roller bearing is provided between the main shaft and the insulating nylon sleeve.

6. The device for measuring the service characteristics of conductive grease for motor bearings according to claim 5, characterized in that: The loading unit and the measuring unit are connected externally through a loading sleeve and a measuring sleeve, and internally through a sensor bracket and a bearing seat. A disc spring is provided between the sensor bracket and the bearing seat, and an observation window is provided on the measuring sleeve; the conductive carbon brush is connected to the main shaft.

7. The device for measuring the service characteristics of conductive grease for motor bearings according to claim 4, characterized in that: The auxiliary bearing and the bearing to be tested are both thrust roller bearings with a separated structure, consisting of a shaft ring, a seat ring, a roller and a cage. The inner surface of the shaft ring is in contact with the surface of the main shaft, and the inner surface of the seat ring is separated from the surface of the main shaft.

8. The device for measuring the service characteristics of conductive grease for motor bearings according to claim 4, characterized in that: The temperature sensor is against the outer ring of the bearing to be tested; a support adjustment component is also provided at the bottom of the loading sleeve; the ceramic pad is fixed to the sensor bracket by screws; an insulating sleeve is provided between the measuring sleeve and the bearing seat, and a vertical groove is provided on the insulating sleeve. The measuring sleeve and the bearing seat are circumferentially positioned by flat keys; the outer surface of the insulating nylon sleeve is provided with an axial vertical groove; the needle roller bearing is set at the largest shaft diameter of the main shaft.

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