Quantitative diagnosis method of rolling bearing internal fault based on outer ring strain response characteristics

Abstract

The present invention discloses a method for quantitatively diagnosing internal faults of rolling bearings based on outer ring strain response characteristics, relates to the technical field of quantitative diagnosis of internal faults of rolling bearings, solves the technical problem in the prior art that bearing fault diagnosis based on noise signals can only be used to determine whether a bearing fault occurs, but cannot be used to determine the bearing fault location and fault size, proposes to use rolling bearing outer ring strain signals to quantitatively diagnose internal faults of roller rolling bearings, the rolling bearing outer ring strain signals are robust to environmental noise and vibration, and are sensitive to weak internal faults of rolling bearings; proposes to use rolling bearing outer ring strain signals to quantitatively diagnose internal faults of roller rolling bearings, compared with traditional vibration noise signals, rolling bearing outer ring strain timing signals can directly reflect the rolling bearing fault type and size, without the need for complex fault diagnosis algorithms.

Description

Technical Field

[0001] The invention relates to the technical field of quantitative diagnosis of internal faults of rolling bearings, and in particular to a quantitative diagnosis method of internal faults of rolling bearings based on outer ring strain response characteristics. Background Art

[0002] Bearings are important components of various engineering machinery transmission systems. Their operating status directly affects the use of related engineering machinery. During service, under the action of complex external loads, the periodic alternating stress caused by the contact between the rollers and raceways inside the roller bearings may cause early fatigue peeling or block loss of the roller or raceway materials. Quantitative diagnosis of such early faults is the key link and prerequisite for predicting the remaining service life of rolling bearings and condition repair.

[0003] At present, the fault diagnosis inside the bearing is mostly carried out by detecting the bearing temperature, noise or vibration signal. Among them, the bearing temperature is closely related to the bearing lubrication status, running time, speed and load, and the abnormal temperature rise caused by the internal fault of the bearing will only appear in the later stage of the bearing operation when the fault presents a certain scale; and the bearing fault diagnosis based on the noise signal can only be used to determine whether the bearing has a fault, and cannot be used to determine the location and size of the bearing fault. At the same time, the collection of noise signals will be greatly disturbed by environmental factors, and the analysis of noise signals has high requirements on the efficiency and stability of noise reduction and diagnosis algorithms; the existing bearing fault diagnosis based on bearing vibration acceleration signals can mostly analyze the characteristic frequency information of the fault through a certain algorithm program and give a judgment on the fault type, but it still cannot give an accurate diagnosis of the fault size; a small number of quantitative fault diagnosis methods based on vibration signals reported in the literature can only be used for identification of single faults (only outer ring or inner ring or roller), and cannot give an accurate judgment when multiple faults exist;

[0004] In view of the above technical defects, a solution is now proposed. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned problems and to propose a quantitative diagnosis method for internal faults of rolling bearings based on the strain response characteristics of the outer ring.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The quantitative diagnosis method of rolling bearing internal fault based on the outer ring strain response characteristics is as follows:

[0008] Step 1: Perform fault analysis on the rolling bearing and determine whether the rolling bearing has a fault based on the strain response signal characteristics;

[0009] Step 2: Determine the internal fault location of the rolling bearing according to the strain response characteristics at different positions of the outer ring;

[0010] Step 3: Determine the internal fault size of the rolling bearing based on the sudden change characteristics of the outer ring strain signal.

[0011] As a preferred embodiment of the present invention, a rolling bearing is arranged in a bearing seat, a fault-free inner ring is arranged in the bearing seat, a fault-free outer ring is arranged between the fault-free inner ring and the bearing seat, the centers of the fault-free outer ring, the fault-free inner ring and the bearing seat are one point, a fault-free roller is arranged in the gap between the fault-free outer ring and the fault-free inner ring, the fault-free roller is respectively connected to the inner wall of the fault-free outer ring and the outer wall of the fault-free inner ring, and the fault-free roller rolls in the gap between the fault-free outer ring and the fault-free inner ring, and a bearing seat annular groove is arranged on the inner wall of the bearing seat on one side close to the fault-free outer ring; a strain gauge is arranged on the outer wall of the fault-free outer ring on one side close to the bearing seat.

[0012] As a preferred embodiment of the present invention, the specific process of step 1 is as follows:

[0013] An annular groove is introduced into the inner surface of the bearing seat, and whether the rolling bearing has a fault is determined based on the characteristics of the strain response signal; when a fault-free roller rolls over a fault-free outer ring and a fault-free inner ring, the strain response obtained by testing the strain gauge arranged on the outer ring of the rolling bearing shows a smooth and continuous trend; when a single type of fault exists inside the rolling bearing, the fault-free roller rolls over the faulty outer ring and the fault-free inner ring, the faulty roller rolls over the fault-free outer ring and the fault-free inner ring, and the fault-free roller rolls over the fault-free outer ring and the faulty inner ring. The strain response obtained by testing the strain gauge arranged on the outer ring of the rolling bearing will show a sudden change characteristic of first decreasing and then increasing within a roller passing cycle.

[0014] As a preferred embodiment of the present invention, the specific process of step 2 is as follows:

[0015] Determine the internal fault location of the rolling bearing based on the strain response characteristics at different positions of the outer ring; when the strain response at a fixed strain measuring point in the load-bearing area shows a sudden change characteristic of first decreasing and then increasing in each strain cycle, it indicates that the internal fault of the rolling bearing is located at the position of the measuring point on the outer ring raceway surface;

[0016] When the strain response at each strain measuring point in the load-bearing area shows a sudden change feature of first decreasing and then increasing in the order of the roller rolling, it indicates that the internal fault of the rolling bearing is located on the roller surface;

[0017] When the strain response at each strain measuring point in the load-bearing area shows a sudden change that first decreases and then increases, it indicates that the internal fault of the rolling bearing is located on the inner ring raceway surface;

[0018] When the strain signals measured by the strain measuring points at different positions in the bearing area of ​​the rolling bearing present the superposition of the three mutation characteristics mentioned above, the superposition of the three strain response mutation characteristics will not lose the fault location information contained therein. Therefore, the specific fault location when multiple faults are coupled can still be clearly judged based on the strain mutation characteristics at different positions of the outer ring of each fault.

[0019] As a preferred embodiment of the present invention, the specific steps of step three are as follows:

[0020] The internal fault size of the rolling bearing is determined based on the mutation characteristics of the outer ring strain signal; the fault passing time Δt can be read from the strain signal containing the mutation characteristics of instantaneous decrease first and then increase. Δε After determining the fault type and location according to the strain mutation characteristics at different positions in step 2, the fault passing time Δt can be obtained by the mutation duration of the outer ring strain response. Δε The circumferential size W of the internal fault of the rolling bearing is determined by the relative linear velocity Δv between the roller raceway (when the fault is in the outer ring raceway and the roller, Δv is the relative linear velocity of the contact point between the outer ring raceway and the roller; when the fault is in the inner ring raceway, Δv is the relative linear velocity of the contact point between the inner ring raceway and the roller), that is: W = ΔvΔtΔε.

[0021] In summary, the advantages of the present invention include:

[0022] 1. The present invention proposes to use the rolling bearing outer ring strain signal to quantitatively diagnose the internal fault of the roller rolling bearing. The rolling bearing outer ring strain signal is robust to environmental noise and vibration, and is sensitive to weak internal faults of the rolling bearing;

[0023] 2. The present invention proposes to use the rolling bearing outer ring strain signal to quantitatively diagnose the internal fault of the roller rolling bearing. Compared with the traditional vibration noise signal, the rolling bearing outer ring strain time series signal can directly reflect the rolling bearing fault type and size without the need for complex fault diagnosis algorithms;

[0024] 3. The present invention can realize quantitative decoupling and identification of various faults in the case of outer ring, inner ring and roller fault coupling by detecting the strain response characteristics of the outer ring of the rolling bearing at different positions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0026] Figure 1 It is a flow chart of the strain testing method at different positions of the outer ring of a rolling bearing provided by the present invention;

[0027] Figure 2 It is a schematic diagram of a strain test scheme at different positions of the outer ring of a rolling bearing provided by the present invention;

[0028] Figure 3 It is a schematic diagram of the strain response of the outer ring of the rolling bearing provided by the present invention when there is no internal fault;

[0029] Figure 4 It is a schematic diagram of the outer ring strain response when there is a fault inside the rolling bearing provided by the present invention;

[0030] Figure 5 It is a schematic diagram of strain time series signals in different directions when carrying out quantitative diagnosis of outer ring fault based on strain response provided by the present invention;

[0031] Figure 6 It is a schematic diagram of strain time series signals in different directions when quantitative diagnosis of roller faults is carried out based on strain response provided by the present invention;

[0032] Figure 7 It is a schematic diagram of strain time series signals in different directions when carrying out quantitative diagnosis of inner ring fault based on strain response provided by the present invention;

[0033] Figure 8 It is a schematic diagram of strain time series signals in different directions when quantitative diagnosis of outer ring, roller and inner ring coupling fault is carried out based on strain response provided by the present invention;

[0034] Explanation of the reference numerals: 1. strain gauge; 2. normal outer ring; 21. faulty outer ring; 3. normal roller; 31. faulty roller; 4. normal inner ring; 41. faulty inner ring; 5. annular notch of bearing seat; 6. bearing seat. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] See also Figure 1As shown in FIG. 1 , a quantitative diagnosis method for internal faults of rolling bearings based on the outer ring strain response characteristics is firstly to introduce a bearing seat annular notch 5 on the inner surface of the bearing seat 6, as shown in FIG. Figure 2 As shown, several strain gauges 1 are arranged at equal intervals in the bearing area of ​​the rolling bearing, and the rolling bearing strain response test is carried out at different positions of the outer ring of the rolling bearing. Then, according to the strain response characteristics of the outer ring of the rolling bearing, quantitative diagnosis of the type and size of the internal fault of the rolling bearing is carried out, which includes the following three steps:

[0038] Step 1: Determine whether the rolling bearing is faulty based on the strain response signal characteristics. Figure 3 As shown, when the fault-free roller 3 rolls over the fault-free outer ring 2 and the fault-free inner ring 4, the strain response obtained by testing the strain gauge 1 arranged on the outer ring of the rolling bearing shows a smooth and continuous trend;

[0039] like Figure 4 As shown in Figure 2, when there is a single type of fault inside the rolling bearing ( Figure 4 (a) is a schematic diagram of a non-faulty roller 3 rolling over a faulty outer ring 21 and a non-faulty inner ring 4. Figure 4 (b) is a schematic diagram of the faulty roller 31 rolling over the fault-free outer ring 2 and the fault-free inner ring 4. Figure 4 (c) is a schematic diagram of a healthy roller 3 rolling over a healthy outer ring 2 and a faulty inner ring 41. The strain response obtained by testing the strain gauge 1 arranged on the outer ring of the rolling bearing shows a sudden change feature of first decreasing and then increasing in a roller passing cycle. Therefore, it can be judged whether there is a fault inside the rolling bearing based on whether the strain response signal of the outer ring of the rolling bearing shows a sudden change feature of first decreasing and then increasing.

[0040] Step 2: Determine the internal fault location of the rolling bearing based on the strain response characteristics at different positions of the outer ring; when the strain response at a fixed strain measuring point in the load-bearing area shows a sudden change characteristic of first decreasing and then increasing in each strain cycle, such as Figure 5 As shown in the figure, it indicates that the internal fault of the rolling bearing is located at the position of the measuring point on the outer ring raceway. When the strain response of each strain measuring point in the load-bearing area shows a sudden change characteristic of first decreasing and then increasing in the order of the roller rolling, as shown in the figure below: Figure 6 As shown in the figure, it indicates that the internal fault of the rolling bearing is located on the roller surface. When the strain response at each strain measuring point in the load-bearing area shows a sudden change characteristic of first decreasing and then increasing, such as Figure 7 As shown in the figure, it indicates that the internal fault of the rolling bearing is located on the inner ring raceway surface. When the strain signals measured by the strain measuring points at different positions in the bearing area of ​​the rolling bearing show the superposition of the above three mutation characteristics, such as Figure 8 As shown in the figure, the superposition of the three strain response mutation characteristics does not lose the fault location information contained therein, so the specific fault location when multiple faults are coupled can still be clearly determined based on the strain mutation characteristics at different positions of the outer ring of each fault;

[0041] Step 3: Determine the internal fault size of the rolling bearing based on the sudden change characteristics of the outer ring strain signal. Figure 4 As shown in the figure, in the strain signal containing the sudden change feature of instantaneous decrease first and then increase, the fault passing time Δt can be read Δε After determining the fault type and location according to the strain mutation characteristics at different positions in step 2, the circumferential size W of the internal fault of the rolling bearing can be determined by the mutation duration of the outer ring strain response, i.e., the fault passage time ΔtΔε and the relative motion linear velocity Δv between the roller raceway (when the fault is in the outer ring raceway and roller, Δv is the relative linear velocity of the contact point between the outer ring raceway and the roller; when the fault is in the inner ring raceway, Δv is the relative linear velocity of the contact point between the inner ring raceway and the roller). That is: W = Δv · Δt Δε .

[0042] When the present invention is in use, a fault analysis is performed on the rolling bearing, and whether a rolling bearing fault occurs is determined based on the strain response signal characteristics; the internal fault position of the rolling bearing is determined based on the strain response characteristics at different positions of the outer ring; and the internal fault size of the rolling bearing is determined based on the sudden change characteristics of the outer ring strain signal.

[0043] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A quantitative diagnosis method for internal faults of rolling bearings based on the outer ring strain response characteristics, characterized in that: The specific steps are as follows: Step 1: Perform fault analysis on the rolling bearing and determine whether the rolling bearing has a fault based on the strain response signal characteristics. The specific process of step 1 is as follows: An annular bearing seat groove (5) is introduced into the inner surface of the bearing seat (6), and whether the rolling bearing has a fault is determined based on the strain response signal characteristics; when the fault-free roller (3) rolls over the fault-free outer ring (2) and the fault-free inner ring (4), the strain response obtained by testing the strain gauge (1) arranged on the outer ring of the rolling bearing shows a smooth and continuous trend; when a single type of fault exists inside the rolling bearing, the fault-free roller (3) rolls over the fault-free outer ring (21) and the fault-free inner ring (4), the faulty roller (31) rolls over the fault-free outer ring (2) and the fault-free inner ring (4), and the fault-free roller (3) rolls over the fault-free outer ring (2) and the faulty inner ring (41), and the strain response obtained by testing the strain gauge (1) arranged on the outer ring of the rolling bearing shows a sudden change characteristic of first decreasing and then increasing within a roller passing cycle; Step 2: Determine the internal fault location of the rolling bearing according to the strain response characteristics at different positions of the outer ring; the specific process of step 2 is as follows: Determine the internal fault location of the rolling bearing based on the strain response characteristics at different positions of the outer ring; when the strain response at a fixed strain measuring point in the load-bearing area shows a sudden change characteristic of first decreasing and then increasing in each strain cycle, it indicates that the internal fault of the rolling bearing is located at the position of the measuring point on the outer ring raceway surface; When the strain response at each strain measuring point in the load-bearing area shows a sudden change feature of first decreasing and then increasing in the order of the roller rolling, it indicates that the internal fault of the rolling bearing is located on the roller surface; When the strain response at each strain measuring point in the load-bearing area shows a sudden change characteristic of first decreasing and then increasing, it indicates that the internal fault of the rolling bearing is located on the inner ring raceway surface; When the strain signals measured by the strain measuring points at different positions in the bearing area of ​​the rolling bearing present the form of superposition of the above three mutation characteristics, the superposition of the three strain response mutation characteristics will not lose the fault location information contained therein, so the specific fault location when multiple faults are coupled can still be clearly determined based on the strain mutation characteristics at different positions of the outer ring of each fault; Step 3: Determine the internal fault size of the rolling bearing according to the sudden change characteristics of the outer ring strain signal; the specific steps of step 3 are as follows: The internal fault size of the rolling bearing is determined based on the sudden change characteristics of the outer ring strain signal; the fault passing time can be read from the strain signal containing the sudden change characteristics of instantaneous decrease first and then increase. After determining the fault type and location according to the strain mutation characteristics at different positions in step 2, the fault passing time can be calculated by the duration of the mutation of the outer ring strain response. Relative linear velocity between the roller raceway Δ v (When the fault is in the outer ring raceway and roller, Δ v is the relative linear velocity between the outer ring raceway and the roller contact point; When the fault is in the inner ring raceway, Δ v is the relative linear velocity of the inner ring raceway and the roller contact point) to determine the circumferential dimension W of the internal fault of the rolling bearing, that is: .

2. The rolling bearing internal fault quantitative diagnosis method based on outer ring strain response characteristics according to claim 1 is characterized in that: The rolling bearing is arranged in a bearing seat (6), a fault-free inner ring (4) is arranged in the bearing seat (6), a fault-free outer ring (2) is arranged between the fault-free inner ring (4) and the bearing seat (6), the centers of the fault-free outer ring (2), the fault-free inner ring (4) and the bearing seat (6) are one point, a fault-free roller (3) is arranged in the gap between the fault-free outer ring (2) and the fault-free inner ring (4), the fault-free roller (3) is respectively connected to the inner wall of the fault-free outer ring (2) and the outer wall of the fault-free inner ring (4), and the fault-free roller (3) rolls in the gap between the fault-free outer ring (2) and the fault-free inner ring (4), and a bearing seat annular notch (5) is arranged on the inner wall of the bearing seat (6) on one side close to the fault-free outer ring (2); and a strain gauge (1) is arranged on the outer wall of the fault-free outer ring (2) on one side close to the bearing seat (6).

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