A large size plain bearing test method

Abstract

The application discloses a large sliding bearing testing method and relates to the technical field of electromechanical equipment. The method comprises the following steps: placing a large sliding bearing horizontally and in a natural state; setting a tester; using the tester to obtain the height change value of the top of an oil flinger or the top of a journal through one of first and second sight holes before and after starting a high-pressure oil pump, and taking the height change value as the bearing bush oil gap value after starting the high-pressure oil pump; and using the tester to obtain the height change value through the first and second sight holes respectively, directly measuring the oil gap uplift of the journal inside the large sliding bearing, and being simple in operation, accurate in measurement, avoiding the work of disassembling the shaft and the bearing, and thus having the advantages of saving time and effort; and through the measurement of the journal at two different positions in the axial direction, the uniformity of the bearing oil film can be judged, the oil film thickness of the large sliding bearing in the axial direction can be judged, and the occurrence of such bearing accidents can be effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of electromechanical equipment technology, and in particular to a testing method for large sliding bearings. Background Technology

[0002] For sliding bearings in large rotating equipment, such as those in large electric motors and generators, it is often necessary to accurately measure and adjust the high-pressure lubricating oil film thickness clearance, or oil gap for short. Typically, the oil gap is measured by measuring the difference in height of the shaft surface near the bearing housing before and after the high-pressure oil pump is started. For ease of operation, this measurement is usually performed with the motor engaged.

[0003] Existing measurement methods treat the motor shaft as an ideal rigid body, neglecting the microscopic bending caused by various pressures on the motor shaft. Therefore, when adjusting the high-pressure lubrication oil gap of the motor bearing, it is assumed that the height change of the shaft surface near the bearing housing is equal to the change of the corresponding high-pressure oil gap of the bearing.

[0004] However, in the realm of sliding bearings in large rotating equipment, such as large motors, when the motor shaft remains connected to the transmission shaft, the end of the motor shaft is subjected to pressure from both the transmission shaft and the motor shaft itself, causing microscopic elastic bending. The oil clearance of large motor bearings ranges from micrometers, and the aforementioned effect of motor shaft bending may fall within this order of magnitude, potentially leading to a significant error in the measured lubrication oil clearance. Furthermore, the bearing shells of large sliding bearings are typically spherical self-aligning shells (the support surface under the bearing shell is spherical). When the spherical surface of the shell does not align well with the spherical surface of the support belt, its self-aligning function deteriorates. This can also cause an axial imbalance in the oil film thickness clearance of the bearing shell, forming a wedge-shaped oil film, which can easily lead to bearing failure. This imbalance cannot be detected by existing traditional oil clearance measurement methods. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a testing method for large sliding bearings.

[0006] This application provides a testing method for a large sliding bearing. The large sliding bearing includes a stationary part and a rotating part. The stationary part includes a bearing housing, a bearing cover connected to the bearing housing, and an upper bearing shell and a lower bearing shell located inside the bearing housing and the bearing cover. The rotating part includes a journal and two oil slinger rings mounted on the journal. The journal is located between the upper bearing shell and the lower bearing shell. The bearing cover of the large sliding bearing has a first viewing hole and a second viewing hole respectively for the two oil slinger rings. The special testing method for the large sliding bearing includes: placing the large sliding bearing flat and in a natural state; setting up a special testing instrument; and using the special testing instrument to obtain the height change value of the top of the oil slinger ring or the top of the journal through one of the first and second viewing holes before and after the high-pressure oil pump is started, as the bearing oil clearance value after the high-pressure oil pump is started.

[0007] The beneficial effects of this application are as follows: It provides a special testing method for large sliding bearings. Based on the structure of large sliding bearings, a special testing instrument is used to obtain the height change value of the top of the oil slinger ring or the top of the journal through one of the viewing holes before and after the high-pressure oil pump is started. This height change value is used as the bearing oil clearance value after the high-pressure oil pump is started. The special testing instrument obtains the height change value through the first and second viewing holes respectively, directly measuring the oil clearance rise at the journal inside the large sliding bearing. The operation is simple and the measurement is accurate, avoiding the work of disassembling and installing the shaft, thus having the advantages of saving time and effort. By measuring the journal at two different positions in the axial direction, the uniformity of the bearing oil film can be determined, and whether the oil film thickness of the large sliding bearing is balanced in the axial direction can be determined, effectively avoiding the occurrence of such bearing accidents. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0009] Figure 1 A schematic diagram of the structure of the large sliding bearing provided in this application;

[0010] Figure 2 A first schematic diagram of the special test method for large sliding bearings provided in this application;

[0011] Figure 3 A second schematic diagram of the special test method for large sliding bearings provided in this application;

[0012] Figure 4 A third schematic diagram illustrating the special test method for large sliding bearings provided in this application;

[0013] Figure 5 A schematic diagram of a contact-type dedicated tester involved in the dedicated test method for large sliding bearings provided in this application;

[0014] Figure 6 A flowchart illustrating a dedicated testing method for large sliding bearings provided in this application;

[0015] Figure 7 The fourth schematic diagram is for the special test method for large sliding bearings provided in this application;

[0016] Figure 8 A simplified diagram illustrating the four sets of dedicated testing instruments used in this application;

[0017] Figure 9 This is a schematic diagram showing that h1≈h2 and h3≈h4 are used in the four sets of dedicated testing instruments in this application;

[0018] Figure 10 This is a schematic diagram showing the h1 > h2 > h4 configuration of the four dedicated testing instruments used in this application;

[0019] Figure 11 This is a schematic diagram showing the h3 < h1 < h2 configuration of the four sets of dedicated testing instruments used in this application.

[0020] Attached diagram labels: 11-Bearing housing, 12-Bearing cap, 121-Lifting ring, 13-Upper bearing shell, 14-Lower bearing shell, 21-Jirder, 22-Oil slinger ring, 31-First viewing hole, 32-Second viewing hole, 41-Contact-type special tester, 411-Tester, 412-Extension rod, 413-Clamping rod, 413a-Nut. Detailed Implementation

[0021] As shown in the background art, the shaft undergoes elastic bending at the microscopic level due to the influence of various pressures. The special test method of the present invention measures the bearing directly above the oil film inside the bearing bush, while the traditional measurement method measures the shaft surface near the bearing indirectly. This largely avoids the errors caused by the microscopic bending of the shaft.

[0022] First, the present invention uses a dedicated testing instrument to directly measure the height change of the top of the oil slinger ring or the top of the journal above the oil film inside the bearing before and after the high-pressure oil pump starts, using the viewing hole of the oil slinger ring. This measurement is taken as the bearing oil clearance value after the high-pressure oil pump starts.

[0023] Secondly, the present invention sets up two or four sets of dedicated testing instruments to measure the height changes of the top of the outer left shaft surface of the bearing cover, the top of the oil slinger ring or the top of the journal at the first viewing hole, the top of the oil slinger ring or the top of the journal at the second viewing hole, and the top of the outer right shaft surface of the bearing cover before and after the oil pump is started. The measured values ​​are compared according to certain rules to determine whether the bearing clearance is balanced.

[0024] The principle is as follows: To address the micro-bending of the shaft in such large transmission mechanisms caused by various pressures, large sliding bearings typically employ a spherical self-aligning bearing design. However, when corrosion or other factors cause malfunction of the spherical self-aligning function, it may lead to an uneven axial oil gap in the bearing bush. Therefore, a method for determining this imbalance is needed. This invention uses a dedicated testing instrument to directly measure the oil gap value above the bearing bush oil gap through two oil slinger sight holes, and compares the two oil gap values ​​to determine whether the oil gap is balanced. However, because the two sight holes are very close together, the shaft stiffness is affected within a short distance. The existence of uneven oil gaps makes it difficult to determine whether the oil gap is balanced simply by comparing the oil gap values ​​measured at the two viewing holes. Therefore, a testing method using the aforementioned four sets of dedicated testing instruments was designed. For example, when a wedge-shaped oil gap with a left-larger and right-smaller imbalance occurs, the oil film on the right side with the smaller gap becomes thinner or even close to zero. At this point, the journal approximately touches the bearing bush, forming a similar fulcrum. When the oil pump is started and the oil film on the left side rises, the seesaw effect causes the dedicated testing instrument located on the outermost right bearing cap to rise even less or even fall, resulting in h1 > h2 > h4. Similarly, when a wedge-shaped oil film with a right-larger and left-smaller imbalance occurs, the result will be h3 < h1 < h2. When h1 ≈ h2 and h3 ≈ h4, it indicates that the oil gap is normally balanced. This allows for a direct and simple way to determine whether the oil gap is balanced, avoiding the tedious disassembly and inspection of the bearing.

[0025] To make the test more accurate, a dedicated testing instrument with a measurement accuracy of 0.001 mm was used.

[0026] This invention provides a dedicated testing method for large sliding bearings. Please refer to... Figure 1 , Figure 1 The present invention illustrates several structural features of the large sliding bearing involved in this method, including a stationary part and a rotating part. The stationary part includes a bearing housing 11, a bearing cover 12, an upper bearing shell 13, and a lower bearing shell 14. The bearing cover 12 is detachably connected to the bearing housing 11. The upper bearing shell 13 and the lower bearing shell 14 are arranged vertically and installed inside the bearing housing 11 and the bearing cover 12. The rotating part includes a journal 21 and two oil slinger rings 22 mounted on the journal 21. The two oil slinger rings 22 are spaced apart. The journal 21 is located between the upper bearing shell 13 and the lower bearing shell 14. The bearing cover of the large sliding bearing has a first viewing hole 31 and a second viewing hole 32 respectively for the two oil slinger rings 22. The viewing holes include a portion of the channel located in the bearing cover 12 and a portion of the channel located in the upper bearing shell 13.

[0027] Please refer to the reference. Figures 1 to 6 This embodiment provides a dedicated testing method for large sliding bearings, specifically including:

[0028] When the large sliding bearing is laid flat and in its natural state, the top of the inner edge of the oil slinger ring 22 is in close contact with the top of the outer edge of the journal 21, and the two are in close contact without gaps.

[0029] After being laid flat, a dedicated testing instrument is set up. The instrument is used to obtain the height change value of the top of the oil slinger ring or the top of the journal through one of the viewing holes before and after the high-pressure oil pump is started. This value is used as the bearing oil clearance value after the high-pressure oil pump is started.

[0030] Regarding the operation method of the dedicated testing instrument, such as Figure 2 and Figure 3 As shown, the process includes: after being laid flat, obtaining the height change value of the top of the oil slinger ring 22 or the top of the journal 21 through the first viewing hole 31 using a special testing instrument before and after the high-pressure oil pump is started; the height change value reflects the oil gap thickness at the position directly below the first viewing hole 31; obtaining the height change value of the top of the other oil slinger ring 22 or the top of the journal 21 through the second viewing hole 32 using a special testing instrument before and after the high-pressure oil pump is started; the height change value reflects the oil gap thickness at the position directly below the second viewing hole 32.

[0031] After obtaining two height change values, the two values ​​are compared, including determining whether the oil film thickness of the large sliding bearing is uniform in the axial direction. When the two height change values ​​are equal, it indicates that the oil film thickness of the large sliding bearing is uniform in the axial direction; otherwise, it is unbalanced and further adjustments to the large sliding bearing are needed until the oil film thickness is uniform in the axial direction.

[0032] Regarding the operation method of the dedicated testing instrument, such as Figure 4 As shown, it also includes: installing two sets of special testing instruments at the first viewing hole 31 and the second viewing hole 32 simultaneously, accurately measuring and recording the height change values ​​of the top of the oil slinger ring 22 or the top of the journal 21 at the two locations before and after the high-pressure oil pump is started, and comparing the two values ​​to determine whether the oil film thickness of the large sliding bearing is uniform in the axial direction.

[0033] Regarding the aforementioned "obtaining the height change value before and after the high-pressure oil pump starts", for example, the top of journal 21 has a height value before the high-pressure oil pump starts, and the top of journal 21 rises to another height value after the high-pressure oil pump starts and stabilizes. The difference between these two height values ​​is finally obtained by a special testing instrument, which is the height change value described in this embodiment.

[0034] Regarding the aforementioned "height change value of the top of the oil slinger ring 22 or the top of the journal 21", specifically, the measurement in this method is performed when the large sliding bearing is laid flat and under natural gravity. In this state, the top of the inner edge of the oil slinger ring 22 is in close contact with the top of the outer edge of the journal 21. Therefore, the height change value of the top of the oil slinger ring 22 before and after the high-pressure oil pump is started reflects the oil gap thickness; however, if the oil slinger ring 22 is moved from... Figure 1If the position in the middle is moved to the left or right, the journal 21 area at the lowest position of the oil slinger ring 22 will be exposed. The special tester directly measures the height change at the journal 21 position directly below the first viewing hole 31. The measured height change also reflects the oil gap thickness directly below the first viewing hole 31.

[0035] In obtaining the above height change values, it is necessary to keep the dedicated testing instrument and the stationary part of the large sliding bearing relatively stationary, for example, to keep the dedicated testing instrument and the bearing cover 12 relatively fixed. The change in the reading of the dedicated testing instrument reflects the change in the height position of the rotating part before and after the oil is injected between the journal 21 and the bearing bush, and also the oil gap thickness. Using the dedicated testing method of this embodiment, the relative positional dimensional relationship between the rotating part and the stationary part inside the large sliding bearing in the vertical direction of space can be directly measured.

[0036] The above describes the position directly below the first viewing hole 31. When the first viewing hole 31 is arranged radially along the shaft or bearing, the direction directly below the first viewing hole 31 is the radial direction of the shaft or bearing, and the position directly below the first viewing hole 31 is the peripheral area of ​​the journal 21 directly opposite.

[0037] The above compares the magnitude of the two height change values, that is, the oil gap thickness of journal 21 at two different positions in the axial direction. When the two values ​​are equal, it means that the oil film thickness is in a balanced state in the axial direction.

[0038] In summary, based on the structure of large sliding bearings, this method uses a dedicated testing instrument to obtain height change values ​​through the first viewing hole 31 and the second viewing hole 32, directly measuring the oil gap lift at the journal 21 inside the large sliding bearing. The operation is simple, the measurement is accurate, and it avoids the work of disassembling and installing the shaft, thus saving time and effort. By measuring the journal 21 at two different axial positions, the uniformity of the bearing oil film can be determined, and whether the oil film thickness of the large sliding bearing is balanced axially, effectively preventing the occurrence of such bearing accidents.

[0039] In existing technology, the oil clearance of a large sliding bearing is measured by measuring the difference in height of the shaft surface near the bearing housing 11 before and after the high-pressure oil pump is started. Existing technology considers the height change of the shaft surface near the bearing housing 11 as the corresponding change in the high-pressure oil clearance of the bearing. When the motor shaft remains connected to the transmission shaft, the motor shaft end is affected by the transmission shaft and pressure, causing the motor shaft to undergo microscopic elastic bending. This elastic bending will cause a non-negligible error between the height change of the shaft surface near the bearing housing 11 and the actual oil clearance thickness of the journal 21, resulting in inconsistencies between the measured result and the actual oil clearance thickness.

[0040] Compared to the above methods, the method of this embodiment directly measures the oil gap thickness at journal 21, eliminating the errors present in the method of measuring the height change of the shaft surface near bearing housing 11, and achieving a simple, easy and accurate measurement.

[0041] In some implementation schemes, unlike the scheme described above which uses two sets of dedicated testing instruments, please refer to... Figure 7 and Figure 8 Four sets of dedicated testing instruments B3, B1, B2, and B4 were sequentially installed on the shaft surface on the left side of the bearing cover, at the first viewing hole, at the second viewing hole, and on the shaft surface on the right side of the bearing cover, respectively. Dedicated testing instruments B3 and B4 measured the top of the shaft surface at the above-mentioned positions, and dedicated testing instruments B1 and B2 measured the top of the oil slinger ring or the top of the journal at the above-mentioned two locations, respectively. Before and after the high-pressure oil pump was started, the height change values ​​at the above four dedicated testing instruments were measured and recorded. The height change values ​​were recorded as h3, h1, h2, and h4, respectively, corresponding to the height change values ​​at the dedicated testing instruments B3, B1, B2, and B4.

[0042] The rules for comparing the changes in height are as follows: (1) When h1≈h2 and h3≈h4, such as Figure 9 As shown, this indicates that the oil film is basically balanced; (2) When h1 > h2 > h4, as Figure 10 As shown, this indicates that the oil film has a wedge shape with a larger left side and a smaller right side; (3) When h3 < h1 < h2, as Figure 11 As shown, the oil film exhibits a wedge shape, with the left side smaller than the right.

[0043] In detail: A testing method using the aforementioned four sets of dedicated testing instruments was designed. For example, when an uneven wedge-shaped oil gap occurs (larger on the left and smaller on the right), the oil film on the right side, where the gap is smaller, becomes thinner or even close to zero. Here, the journal approximately touches the bearing bush, forming a similar fulcrum. When the left oil pump is started, the oil film on the left rises, and the seesaw effect causes the dedicated testing instrument located on the outermost right bearing cap to rise even less or even fall, resulting in h1 > h2 > h4. Similarly, when a wedge-shaped oil film occurs (larger on the right and smaller on the left), the result will be h3 < h1 < h2. When h1 ≈ h2 and h3 ≈ h4, it indicates that the oil gap is normally balanced. This allows for a direct and simple way to determine whether the oil gap is balanced, avoiding the tedious process of disassembling and inspecting the bearing.

[0044] Based on the above judgment rules, further restrictions are made as follows:

[0045] When |h1-h2|*100% / {(h1+h2) / 2}≤90% and |h3-h4|*100% / {(h3+h4) / 2}≤85%, it is determined that the oil film thickness of the large sliding bearing is axially balanced.

[0046] When h1 > h2 > h4, and (h1-h2)*100% / {(h1+h2) / 2} > 90%, and (h2-h4)*100% / {(h2+h4) / 2} > 85%, it is determined that the bearing oil film has a wedge shape with a larger left side and a smaller right side in the axial direction.

[0047] If h2 > h1 > h3, and (h2-h1)*100% / {(h1+h2) / 2} > 90%, and (h1-h3)*100% / {(h1+h3) / 2} > 85%, then the bearing oil film is determined to have a wedge shape with a smaller left side and a larger right side in the axial direction.

[0048] In some embodiments, the dedicated testing instrument includes a non-contact dedicated testing instrument, which is fixed relative to the stationary part of the large sliding bearing. The non-contact dedicated testing instrument is used to obtain the height change value. The non-contact dedicated testing instrument may employ methods such as laser measurement.

[0049] In some embodiments, the non-contact dedicated tester is spaced apart from and relatively fixed to the large sliding bearing. The non-contact dedicated tester also includes monitoring the height change of the top of the oil slinger ring 22 through a first viewing port 31 and / or a second viewing port 32 when the large sliding bearing is in operation. This enables monitoring of the equipment's dynamic operation, effectively preventing bearing accidents and resulting in significant economic and social benefits.

[0050] Regarding the monitoring of equipment during dynamic operation, in some implementations, in the above-mentioned scheme of using four sets of dedicated testing instruments B3, B1, B2, and B4, the dedicated testing instruments can be non-contact dedicated testing instruments, including measuring and monitoring the changes in height values ​​at B3, B1, B2, and B4 when the large sliding bearing is in operation, in order to monitor and judge the operating status of the bearing.

[0051] Obtaining the height change value at the aforementioned locations using a dedicated testing instrument involves selecting the appropriate measurement accuracy. In some implementations, a measurement accuracy of 0.01 mm is used. In other implementations, a measurement accuracy of 0.001 mm is used. Considering that the numerical range of motor bearing oil clearance in the prior art is on the order of micrometers (0.1 mm), the measurement accuracy of the dedicated testing instrument is limited to below micrometers.

[0052] In some embodiments, the dedicated tester includes a contact-type dedicated tester 41. It should be noted that the contact-type dedicated tester 41 can be with or without an extension rod. Specifically, in the schemes employing dedicated testers B3, B1, B2, and B4, B1 and B2 are contact-type dedicated testers with extension rods, while B3 and B4 are contact-type dedicated testers without extension rods. The difference between contact-type and non-extension-type dedicated testers lies in whether or not an extension rod is provided; other aspects remain the same, including detachability, which includes the clamping rod 413 described below.

[0053] like Figure 5 As shown, the contact-type dedicated tester 41 includes a tester 411 and an extension rod 412 fixedly connected to the probe of the tester 411, as shown. Figure 2 and Figure 3 As shown, the tester 411 is detachably fixed relative to the stationary part of the large sliding bearing, and the extension rod 412 is configured to extend into the first viewing hole 31, the second viewing hole 32, and contact the top of the oil slinger ring 22 or the top of the journal 21. In this configuration, the extension rod 412 effectively extends the probe of the tester 411 to facilitate smooth contact with the oil slinger ring 22 or the journal 21.

[0054] In the scheme employing the above four sets of dedicated testing instruments B3, B1, B2, and B4, please refer to... Figure 7 and Figure 8 The dedicated testers B1 and B2 can use the extension rod as described above, while the dedicated testers B3 and B4 generally do not need to use this extension rod.

[0055] In some implementations, the length of the extension rod 412 is set to be adjustable to accommodate large sliding bearings with different radial dimensions.

[0056] Regarding the adjustable length of the extension rod 412, some embodiments employ a telescopic rod combined with a locking mechanism, such as a tightening screw. Two threaded sleeves, working in conjunction with the locking mechanism (e.g., a tightening screw), are used to fix the extended rod 412 after length adjustment, preventing changes in its height during actual measurement and ensuring the accuracy of the measurement results. Adjustable rods are widely used in the prior art, and most can be applied as extension rods in this embodiment.

[0057] In some implementation methods, please refer to Figure 2 and Figure 3The tester 411 is connected to a clamping rod 413, and two nuts 413a are threaded onto the body of the clamping rod 413. The clamping rod 413 passes through the lifting ring 121 of the bearing cover 12. After the clamping rod 413 passes through the lifting ring 121, the position of the nuts 413a on the clamping rod 413 is adjusted so that the two nuts 413a press against the lifting ring 121 from the left and right, thereby achieving relative fixation between the tester 411 and the large sliding bearing.

[0058] In some embodiments, the relative fixation of the tester 411 and the large sliding bearing can also be achieved by magnetic attraction.

[0059] In some implementations, the tester 411 includes a dial indicator, or a micrometer indicator, to meet the measurement accuracy requirements.

[0060] Based on the dial indicator, in the above-mentioned contact-type dedicated tester 41 including the tester 411 and the extension rod 412, it can be considered that the extension rod 412 is rigidly connected to the probe of the dial indicator, or the extension rod 412 can be directly manufactured by the manufacturer as part of the dial indicator from the beginning.

[0061] In the specific measurement process, it is understood that when selecting a contact-type dedicated tester 41, the extension rod 412 needs to be perpendicular to the journal 21 or the oil slinger ring 22; when selecting a non-contact dedicated tester, such as laser measurement, the laser needs to be perpendicular to the journal 21 or the oil slinger ring 22.

[0062] Based on the above-mentioned special testing method for large sliding bearings, in the scheme of using a contact-type special testing instrument 41, which includes a testing instrument 411 and an extension rod 412, the special testing instrument obtains the height change value of the top of the oil slinger ring 22 or the top of the journal 21 through the first viewing hole 31 before and after the high-pressure oil pump is started. This includes:

[0063] Open the cover of the first viewing hole 31; after opening the cover of the first viewing hole 31, insert the extension rod 412 of the contact-type special tester 41 into the first viewing hole 31, fix the clamping rod 413 relative to the lifting ring 121, adjust the length of the extension rod 412 so that the end of the extension rod 412 contacts the top of the oil slinger ring 22 or the top of the journal 21; before the high-pressure oil pump is started, record the first measurement data of the tester 411 at this time; after the high-pressure oil pump is started and stabilized, record the second measurement data of the tester 411 at this time; calculate the difference between the first measurement data and the second measurement data, which is the height change value obtained through the first viewing hole 31.

[0064] The height change of the top of the oil slinger ring 22 or the top of the journal 21 is obtained through the second viewing hole 32 before and after the high-pressure oil pump is started using a dedicated testing instrument. This includes: after obtaining the height change value through the first viewing hole 31, opening the cover of the second viewing hole 32; after opening the cover of the second viewing hole 32, inserting the extension rod 412 of the contact-type dedicated testing instrument 41 into the second viewing hole 32, fixing the clamping rod 413 relative to the lifting ring 121, adjusting the length of the extension rod 412 so that the end of the extension rod 412 contacts the top of the oil slinger ring 22 or the top of the journal 21; before the high-pressure oil pump is started, recording the third measurement data of the testing instrument 411 at this time; after the high-pressure oil pump is started and stabilized, recording the fourth measurement data of the testing instrument 411 at this time; and calculating the difference between the third measurement data and the fourth measurement data, which is the height change value obtained through the second viewing hole 32.

[0065] Record the height change value obtained through the first viewing hole 31 and the height change value obtained through the second viewing hole 32, compare the two height change values, and determine whether the oil film thickness of the large sliding bearing is uniform in the axial direction.

[0066] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0067] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A testing method for large sliding bearings, characterized in that, The large sliding bearing includes a stationary part and a rotating part. The stationary part includes a bearing housing, a bearing cover connected to the bearing housing, an upper bearing shell and a lower bearing shell located inside the bearing housing and the bearing cover. The rotating part includes a journal and two oil slinger rings mounted on the journal. The journal is located between the upper bearing shell and the lower bearing shell. The bearing cover of the large sliding bearing has a first viewing hole and a second viewing hole respectively for the two oil slinger rings. The testing method for large sliding bearings includes: The large sliding bearing is laid flat and left in its natural state. A testing instrument is set up, and the height change value of the top of the oil slinger ring or the top of the journal is obtained through one of the first and second viewing holes before and after the high-pressure oil pump is started. This value is used as the bearing oil clearance value after the high-pressure oil pump is started. Four sets of testing instruments B3, B1, B2, and B4 are sequentially installed on the shaft surface on the left side of the bearing cover, at the first viewing hole, at the second viewing hole, and on the shaft surface on the right side of the bearing cover. Testing instruments B3 and B4 measure the top of the shaft surface on the left side and the top of the shaft surface on the right side of the bearing cover, respectively. Testing instruments B1 and B2 measure the top of the oil slinger ring or the top of the journal at the first viewing hole and the second viewing hole, respectively. Before and after the high-pressure oil pump is started, the height change values ​​measured by the four sets of testing instruments are measured and recorded. The height change values ​​are recorded as h3, h1, h2, and h4, respectively, corresponding to the height change values ​​at the locations of testing instruments B3, B1, B2, and B4. The method for determining whether the oil film thickness of the large sliding bearing is uniform in the axial direction is as follows: When |h1-h2|*100% / {(h1+h2) / 2}≤90% and |h3-h4|*100% / {(h3+h4) / 2}≤85%, it is determined that the oil film thickness of the large sliding bearing is axially balanced. When h1 > h2 > h4, and (h1-h2)*100% / {(h1+h2) / 2} > 90%, and (h2-h4)*100% / {(h2+h4) / 2} > 85%, it is determined that the bearing oil film has a wedge shape with a larger left side and a smaller right side in the axial direction. If h2 > h1 > h3, and (h2-h1)*100% / {(h1+h2) / 2} > 90%, and (h1-h3)*100% / {(h1+h3) / 2} > 85%, then the bearing oil film is determined to have a wedge shape with a smaller left side and a larger right side in the axial direction.

2. The testing method for large sliding bearings as described in claim 1, characterized in that, The height change of the top of the oil slinger ring or the top of the journal is obtained through the first viewing hole before and after the high-pressure oil pump is started using a tester. The height change of the top of the other oil slinger ring or the top of the journal is obtained through the second viewing hole before and after the high-pressure oil pump is started using a tester. After obtaining the two height change values, the two height change values ​​are compared to determine whether the oil film thickness of the large sliding bearing is uniform in the axial direction.

3. The testing method for large sliding bearings as described in claim 1, characterized in that, Two sets of testing instruments, B1 and B2, are simultaneously installed at the first and second viewing holes. Before and after the high-pressure oil pump is started, the height change values ​​of the top of the oil slinger ring or the top of the journal at the first and second viewing holes are measured and recorded respectively. The two values ​​are compared to determine whether the oil film thickness of the large sliding bearing is uniform in the axial direction.

4. The testing method for large sliding bearings as described in claim 2, characterized in that, The testing instrument includes a contact testing instrument, which includes a contact testing instrument with an extension rod. The contact testing instrument with the extension rod includes a testing instrument and an extension rod fixedly connected to the probe of the testing instrument. The testing instrument is detachably fixed to the stationary part of the large sliding bearing. The extension rod is configured to extend into the first viewing hole, the second viewing hole, and contact the top of the oil slinger ring or the top of the journal.

5. The testing method for large sliding bearings as described in claim 4, characterized in that, The tester is connected to a clamping rod, and two nuts are threaded onto the body of the clamping rod. The clamping rod passes through the lifting ring of the bearing cover, and the two nuts abut against the lifting ring from the left and right sides to fix the tester to the large sliding bearing.

6. The testing method for large sliding bearings as described in claim 5, characterized in that, The length of the extension rod is adjustable.

7. The testing method for large sliding bearings as described in claim 4, characterized in that, The measurement accuracy of the tester includes 0.001 mm.

8. The testing method for large sliding bearings as described in claim 2, characterized in that, The testing instrument includes a non-contact testing instrument, which is fixed to the stationary part of the large sliding bearing. The non-contact testing instrument is used to obtain the height change value.

9. The testing method for large sliding bearings as described in claim 8, characterized in that, The non-contact testing instrument also includes measuring and monitoring the height changes at points B3, B1, B2, and B4 when the large sliding bearing is in operation, in order to monitor and determine the bearing's operating status.

10. The testing method for large sliding bearings as described in claim 6, characterized in that, The step of obtaining the height change value of the top of the oil slinger ring or the top of the journal through the first viewing hole before and after the high-pressure oil pump is started by a testing instrument includes: Open the cover of the first viewing hole; After opening the cover of the first viewing hole, insert the extension rod of the contact tester into the first viewing hole, fix the clamping rod to the lifting ring, and adjust the length of the extension rod so that the end of the extension rod contacts the top of the oil slinger ring or the top of the journal. Record the first measurement data of the tester before the high-pressure oil pump starts; After the high-pressure oil pump starts and stabilizes, record the second measurement data of the tester at this time; Calculate the difference between the first measurement data and the second measurement data, where the difference is the height change value obtained through the first viewing hole; The step of obtaining the height change value of the top of the other oil slinger ring or the top of the journal through the second viewing hole before and after the high-pressure oil pump is started using a testing instrument includes: After obtaining the height change value through the first viewing hole, open the cover of the second viewing hole; After opening the cover of the second viewing hole, insert the extension rod of the contact tester into the second viewing hole, fix the clamping rod to the lifting ring, and adjust the length of the extension rod so that the end of the extension rod contacts the top of the oil slinger ring or the top of the journal; Before the high-pressure oil pump starts, record the third measurement data of the tester at this time; After the high-pressure oil pump starts and stabilizes, record the fourth measurement data of the tester at this time; The difference between the third measurement data and the fourth measurement data is calculated, and the difference is the height change value obtained through the second viewing hole.

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