Rotating shaft crack non-contact detection device
By installing a non-center symmetric flange and transmission device on the rotating shaft, the lateral vibration response is measured using non-contact vibration measuring equipment, the problem of the inability to detect rotating shaft cracks in the prior art is solved, and non-contact in the working state of the rotating shaft is realized Test.
Patent Information
- Application Number
- CN202421071209.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-16
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2034-05-16
AI Technical Summary
The prior art is difficult to detect cracks in the working state of the rotating shaft, and it is impossible to apply lateral excitation to the rotating shaft and measure its lateral vibration response, resulting in the inability to detect cracks.
A non-contact detection device for shaft cracks is designed. By placing a non-center symmetric flange and transmission device on the rotating shaft, the non-center symmetric flange generates a transverse simple harmonic restraining reaction force excitation during rotation, combined with non-contact The vibration measurement equipment measures the higher harmonics in the lateral steady-state vibration response to determine whether there are cracks in the rotation shaft.
It realizes non-contact detection without the need for excitation equipment in the working state of the shaft. By obtaining the high harmonics in the lateral steady-state vibration response, it accurately determines whether there are cracks in the shaft, and solves the problem of the inability to detect the rotating shaft cracks in the prior art. question.
Smart Images
Figure CN222188753U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of shaft crack detection, and in particular to a shaft crack non-contact detection device. Background Art
[0002] At present, in the field of mechanical industry, shafts are widely used to connect rotating parts and bear and transmit torque during rotation. For rotor systems with high speed and heavy load, surface fatigue cracks are prone to occur on the shaft after long-term operation, inducing shaft breakage and causing failure of the rotation system. Usually, under the action of single compressive stress or tensile stress, the crack interface is in a closed or open state, which has little effect on the vibration of the shaft. However, under the action of periodically changing tensile and compressive stress, the crack interface will undergo periodic opening and closing movements, resulting in contact between the crack interfaces.
[0003] In the prior art, it is necessary to apply lateral simple harmonic excitation to the shaft when the shaft is stopped, and use the high-order harmonics contained in the lateral steady-state vibration response of the shaft as damage features to determine whether there is a crack in the shaft, thereby determining whether there is a crack in the shaft and realizing crack detection.
[0004] However, it is difficult to apply lateral excitation to a rotating shaft that rotates along a fixed axis during operation and measure its lateral vibration response, which makes it impossible to perform crack detection. Utility Model Content
[0005] The embodiments of this specification provide a non-contact detection device for a shaft crack, which is used to partially solve the problems existing in the prior art.
[0006] The embodiments of this specification adopt the following technical solutions:
[0007] This specification provides a non-contact detection device for a rotating shaft crack, comprising:
[0008] Two supports, on which bearings are arranged, and the rotating shaft to be tested is supported by the bearings;
[0009] A transmission device, comprising a transmission gear sleeved on one end of the rotating shaft to be tested, wherein the transmission device drives the rotating shaft to be tested to rotate through the transmission gear;
[0010] A non-center-symmetric flange is sleeved on the other end of the rotating shaft to be measured, and the center of mass of the non-center-symmetric flange deviates from the axis of the rotating shaft to be measured. During the rotation of the rotating shaft to be measured, the non-center-symmetric flange can generate a lateral simple harmonic constraint reaction force excitation to the rotating shaft to be measured, so that the rotating shaft will vibrate laterally while rotating;
[0011] The non-contact vibration measuring equipment is used to measure the lateral steady-state vibration response of the measured shaft during its rotation, and to determine whether there are cracks in the measured shaft by obtaining the high-order harmonics in the lateral steady-state vibration response of the measured shaft.
[0012] Optionally, the transmission device further comprises a belt, a motor and a driving gear sleeved on an output shaft of the motor, the belt is sleeved on the transmission gear and the driving gear, and the motor drives the shaft to be tested to rotate via the belt, the transmission gear and the driving gear.
[0013] Optionally, the non-center-symmetric flange includes a flange and a plurality of bolts, and the bolts are arranged in a non-center-symmetric manner around the flange so that the center of mass of the flange deviates from the axis of the rotating shaft to be measured.
[0014] Optionally, the non-center-symmetrical flange and the transmission gear are respectively sleeved on two proximal support ends of the rotating shaft to be tested.
[0015] Optionally, the transmission device is configured to provide an adjustable speed to drive the shaft to be tested to rotate at a constant speed at the adjustable speed, thereby obtaining lateral simple harmonic constrained reaction force excitations of different frequencies, so that the shaft to be tested undergoes lateral vibration at a corresponding frequency while rotating.
[0016] Optionally, the non-contact vibration measuring device is a laser non-contact vibrometer, which is used to measure the steady-state vibration response of any quantity in the lateral displacement, lateral velocity or lateral acceleration during the rotation of the measured shaft.
[0017] At least one of the above technical solutions adopted in the embodiments of this specification can achieve the following beneficial effects:
[0018] The utility model sets a non-center-symmetric flange on the rotating shaft to be tested, and the center of mass of the non-center-symmetric flange deviates from the axis of the rotating shaft to be tested, so that the non-center-symmetric flange generates a lateral simple harmonic constraint reaction force excitation on the rotating shaft to be tested during the rotation process, thereby causing the rotating shaft to be tested to undergo lateral simple harmonic vibration during the rotation process, and the surface cracks thereof undergo periodic opening and closing movements during the vibration process. Finally, the high-order harmonics in the lateral steady-state vibration response of the rotating shaft to be tested can be obtained through a non-contact vibration measuring device to determine whether there is a crack in the rotating shaft to be tested, thereby realizing non-contact crack detection. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0020] Figure 1 A schematic diagram of a non-contact detection device for a shaft crack provided in this specification;
[0021] Figure 2 A front view schematic diagram of a non-centrosymmetrical flange provided in this specification;
[0022] Figure 3A top view schematic diagram of a non-centrosymmetrical flange provided in this specification;
[0023] Figure 4 This specification provides a time history curve of the lateral steady-state velocity response of a rotating shaft to be tested and a schematic diagram of its spectrum. DETAILED DESCRIPTION
[0024] In order to make the purpose, technical solutions and advantages of this specification more clear, the technical solutions of this application will be clearly and completely described below in combination with the specific embodiments of this specification and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0025] Straight-rod shafts are widely used to connect rotating parts and bear and transmit torque during rotation. However, it is difficult to apply lateral excitation to a shaft that rotates along a fixed axis during operation. Therefore, there is an urgent need for a shaft lateral excitation technology that does not require an excitation device and can adjust the frequency. At the same time, a non-contact measurement method is used to obtain the lateral steady-state vibration response of the shaft, from which high-order harmonics are extracted as damage features to achieve non-contact crack detection.
[0026] The technical solutions provided by various embodiments of the present application are described in detail below in conjunction with the accompanying drawings.
[0027] Figure 1 Schematic diagram of a non-contact detection device for shaft cracks in this specification. Figure 1 It can be seen that the non-contact detection device for rotating shaft cracks may include: two supports 2, a bearing 1, a transmission device, a non-centrosymmetric flange 7 and a non-contact vibration measuring device 8.
[0028] Specifically, the two supports 2 can be a pair of support members, on which a circular hole can be preset, and the bearing 1 can be sleeved in the circular hole of the support 2. When it is necessary to detect the rotating shaft 9 to be tested, the rotating shaft 9 to be tested can be supported by the bearing 1, so that the rotating shaft 9 to be tested can rotate around the axis of the rotating shaft 9 to be tested under the action of external force. Figure 1 The horizontal axis of the middle frame in the support 2 is the rotating shaft 9 to be tested. There is a crack on its surface. Figure 1 Indicated by black lines.
[0029] The external force is provided by a transmission device, which may include a transmission gear 5 sleeved on one end of the rotating shaft 9 to be tested, and the transmission device drives the rotating shaft 9 to be tested to rotate through the transmission gear 5. Specifically, it may include a transmission gear 5 sleeved on one end of the rotating shaft 9 to be tested, a belt 6, a motor 3, and a driving gear 10 sleeved on the output shaft of the motor 3, the belt 6 is sleeved on the transmission gear 5 and the driving gear 10, and the motor 3 drives the rotating shaft 9 to be tested to rotate through the belt 6, the transmission gear 5 and the driving gear 10. By electrically connecting the motor 3 and the external power supply 4, the external power supply 4 provides electric energy, the motor 3 can convert the electric energy into kinetic energy, and then the belt 6, the transmission gear 5 and the driving gear 10 convert the power into driving force to drive the rotating shaft 9 to be tested to rotate in a fixed axis.
[0030] Preferably, the transmission device here can be configured to provide an adjustable speed to drive the measured shaft 9 to rotate at a constant speed at an adjustable speed, thereby obtaining lateral simple harmonic constrained reaction force excitations of different frequencies, so that the measured shaft 9 can vibrate laterally at the corresponding frequency while rotating.
[0031] For the non-center-symmetric flange 7, when testing the rotating shaft 9 to be tested, the non-center-symmetric flange 7 can be sleeved on the other end of the rotating shaft 9 to be tested. Since the center of mass of the non-center-symmetric flange 7 deviates from the axis of the rotating shaft 9 to be tested, according to the center-of-mass motion theorem, the non-center-symmetric flange 7 will be subjected to the lateral simple harmonic constraint reaction force of the rotating shaft 9 to be tested during the rotation process, and its angular frequency is the rotation frequency of the rotating shaft 9 to be tested. According to Newton's third law, the rotating non-center-symmetric flange 7 can generate lateral simple harmonic constraint reaction force excitation on the rotating shaft 9 to be tested, so that the rotating shaft 9 to be tested will undergo lateral simple harmonic vibration during the rotation process.
[0032] Among them, the non-center-symmetrical flange 7 may include a flange and a plurality of bolts, and the bolts are arranged in a non-center-symmetrical manner around the flange, so that the center of mass of the flange deviates from the axis of the rotating shaft 9 to be measured, forming a non-center-symmetrical flange 7. The flange mentioned here refers to a disk-like metal body with several fixing holes opened around the periphery for connecting other things. The flange itself is uniformly symmetrical, and its center of mass is on the central axis of the central circular hole. The utility model converts it into a non-center-symmetrical flange 7 by arranging bolts on the flange non-center-symmetrically. At least one bolt is required here, and this specification provides a schematic diagram of forming a non-center-symmetrical flange with one bolt, such as Figure 2 and Figure 3 shown. Figure 2 This is a front view of a non-centrosymmetric flange in this specification. Figure 3 This is a top view schematic diagram of a non-centrosymmetrical flange in this specification. Figure 2 In the figure, the hexagon and inscribed circle in the lower right corner are bolts. Figure 3It can be seen that on the other side of the flange, the weight can be increased by adding nuts corresponding to the bolts, so that the center of mass of the non-centrally symmetrical flange 7 is further deviated.
[0033] After the non-centrosymmetric flange 7 is sleeved on the rotating shaft 9 to be measured, when the rotating shaft 9 to be measured rotates under the action of the driving force, the rotating non-centrosymmetric flange 7 will exert a lateral simple harmonic constraint reaction force on the rotating shaft 9 to be measured:
[0034] F x (t) = mlω 2 cosωt
[0035] Wherein, ω is its angular frequency, specifically, the rotation frequency of the rotating shaft 9 to be measured, m is the mass of the additional bolts of the flange, l is the vertical distance from the center of the additional bolts to the axis of the rotating shaft 9 to be measured, and t is the time.
[0036] When the non-center-symmetric flange and transmission gear are sleeved on the rotating shaft to be tested, the sleeve position can be determined according to the needs, and this specification does not limit this. Preferably, the non-center-symmetric flange 7 and the transmission gear 5 can be sleeved on the two proximal ends of the rotating shaft 9 to be tested, and the non-center-symmetric flange 7 can be fixed on the rotating shaft 9 to be tested by bolts. Figure 1 As shown, the non-center-symmetric flange 7 is sleeved on the left side near the support, and the transmission gear 5 sleeved on the rotating shaft 9 to be measured is arranged on the right side near the support. This facilitates the selection of measuring points on the rotating shaft to be measured between the non-center-symmetric flange 7 and the transmission gear 5 at the other end to perform continuous measurement of the lateral steady-state vibration response.
[0037] The non-contact vibration measuring device 8 may be a laser non-contact vibrometer, which is used to measure the lateral steady-state vibration response during the rotation of the rotating shaft 9 to be measured, and to determine whether there is a crack in the rotating shaft 9 to be measured by obtaining the high-order harmonics in the lateral steady-state vibration response during the rotation of the rotating shaft 9 to be measured as damage characteristics. The non-contact vibration measuring device 8 can measure the steady-state vibration response of any amount in the lateral displacement, lateral velocity or lateral acceleration during the rotation of the rotating shaft 9 to be measured. Preferably, the center position of the rotating shaft 9 to be measured can be selected for measurement.
[0038] Figure 4 This is a time history curve and spectrum of the lateral steady-state velocity response of a rotating shaft to be tested in this specification. Figure 4 The left side in the middle is the time history curve of the lateral steady-state velocity response of the shaft to be tested, and the right side is the lateral steady-state vibration response spectrum of the shaft to be tested. Figure 4 The figure shows the time history response curve and its frequency spectrum obtained by the non-contact laser vibrometer after the shaft to be tested is tested by the non-contact shaft crack detection device provided in this manual. The shaft to be tested is 500mm long and 10mm in diameter. There is a fatigue crack on the surface 10mm from the right end, which is perpendicular to the shaft axis and about 10mm in length.
[0039] When judging whether the shaft to be tested has cracks, if there is only the first harmonic at the rotation angle frequency in the response spectrum, it indicates that the shaft has no fatigue cracks. If there are higher harmonics at integer multiples of the rotation angle frequency in addition to the first harmonic, it indicates that the shaft has fatigue cracks. Figure 4 The second and third harmonics in the lateral steady-state velocity response spectrum of the shaft shown can be determined Figure 4 The rotating shaft used in the corresponding embodiment has fatigue cracks.
[0040] It should also be noted that the terms “comprises”, “includes” or any other variations thereof in this specification are intended to cover non-exclusive inclusion, that is, in addition to the elements listed in this specification, other elements not explicitly listed may also be included.
[0041] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.
[0042] The above description is only an embodiment of the present specification and is not intended to limit the present specification. For those skilled in the art, the present specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present specification shall be included in the scope of the claims of the present specification.
Claims
1. A non-contact detection device for a rotating shaft crack, characterized in that: include: Two supports (2) are provided with bearings (1) thereon, and the rotating shaft (9) to be tested is supported by the bearings (1); A transmission device, comprising a transmission gear (5) sleeved on one end of the rotating shaft (9) to be tested, wherein the transmission device drives the rotating shaft (9) to be tested to rotate via the transmission gear (5); A non-centrosymmetric flange (7) is sleeved on the other end of the rotating shaft (9) to be measured, and the center of mass of the non-centrosymmetric flange (7) deviates from the axis of the rotating shaft (9) to be measured. During the rotation of the rotating shaft (9) to be measured, the non-centrosymmetric flange (7) can generate a lateral simple harmonic constraint reaction force excitation on the rotating shaft (9) to be measured, so that the rotating shaft (9) to be measured generates lateral vibration while rotating; The non-contact vibration measuring device (8) is used to measure the lateral steady-state vibration response of the rotating shaft (9) to be measured during rotation, and to determine whether the rotating shaft (9) to be measured has cracks by obtaining high-order harmonics in the lateral steady-state vibration response of the rotating shaft (9) to be measured.
2. The non-contact detection device for shaft cracks according to claim 1, characterized in that: The transmission device further comprises a belt (6), a motor (3) and a driving gear (10) sleeved on an output shaft of the motor (3); the belt (6) is sleeved on the transmission gear (5) and the driving gear (10); the motor (3) is used to drive the rotating shaft (9) to be tested to rotate via the belt (6), the transmission gear (5) and the driving gear (10).
3. The non-contact detection device for shaft cracks according to claim 1, characterized in that: The non-centrosymmetric flange (7) comprises a flange and a plurality of bolts, wherein the bolts are arranged in a non-centrosymmetric manner around the flange so that the center of mass of the flange deviates from the axis of the rotating shaft (9) to be measured.
4. The non-contact detection device for shaft cracks according to claim 1, characterized in that: The non-centrosymmetric flange (7) and the transmission gear (5) are respectively sleeved on two proximal support ends of the rotating shaft (9) to be measured.
5. The non-contact detection device for shaft cracks according to claim 1, characterized in that: The transmission device is configured to provide an adjustable rotation speed, and is used to drive the rotating shaft (9) to be tested to rotate at a uniform speed at the adjustable rotation speed, so as to obtain lateral simple harmonic constraint reaction force excitations of different frequencies, so that the rotating shaft (9) to be tested generates lateral vibrations at corresponding frequencies while rotating.
6. The non-contact detection device for shaft cracks according to claim 1, characterized in that: The non-contact vibration measuring device (8) is a laser non-contact vibrometer, which is used to measure the steady-state vibration response of any quantity in the lateral displacement, lateral velocity or lateral acceleration during the rotation of the rotating shaft (9) to be measured.