Ultrasonic flaw detection device for rotating electrical machine

Abstract

An ultrasonic flaw detection device for a rotating electrical machine can be inserted into a gap between a rotor (41) and a stator (31) of the rotating electrical machine. A three-dimensional drive mechanism (2) that follows the curvature and gradient of the surface of the object to be inspected; an elastic mechanism (3) for adjusting the pressing force of the ultrasonic probe (9); and a support structure (5) for an inspector (51) to perform a flaw detection operation. The three-dimensional driving mechanism (2) enables the ultrasonic probe (9) to smoothly follow the curvature and gradient of the surface of the object to be inspected, so that fine pressing force adjustment of the ultrasonic probe (9) and scanning of sliding on the surface of the object to be inspected can be performed, and fine pressing force adjustment performed by a skilled inspector (51) can be reproduced.

Description

Technical Field

[0001] The present application relates to an ultrasonic flaw detection device for a rotating electrical machine. Background Art

[0002] In the maintenance and inspection of rotating electrical machines, the mainstream method has been to remove the stator from the rotor and inspect the wedge portion and retaining ring portion in a disassembled state. However, the operation of removing the rotor requires a long downtime and is costly. Therefore, methods for inspecting rotating electrical machines without removing the rotor from the stator have been proposed. For example, Patent Document 1 discloses a probe-integrated ultrasonic flaw detection device and ultrasonic flaw detection method, in which an ultrasonic probe and a probe drive mechanism are installed within the main body. Furthermore, Patent Document 2 discloses an inspection robot that can be operated from outside the rotating electrical machine via a remote device. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-132402 Patent Document 2: Japanese Patent Application Laid-Open No. 2002-209363 Summary of the Invention Technical problem to be solved by the invention

[0004] The flaw detection device described in Patent Document 1 is a probe-integrated ultrasonic flaw detection device. The ultrasonic probe is connected to a probe drive mechanism and installed within the main body. This poses the problem of not being able to easily change or replace the ultrasonic probe depending on the object being inspected and the target defect. Furthermore, the pressing force of the ultrasonic probe against the object being inspected is controlled by the probe drive mechanism, making it difficult to reproduce the subtle pressure adjustments made by a skilled inspector. Furthermore, the ultrasonic vibrations oscillating from the ultrasonic probe are transmitted to the object being inspected via a gel-like elastic member. Therefore, the ultrasonic probe adheres to the elastic member, making it impossible to reproduce the scanning process performed by a skilled inspector, where the ultrasonic probe slides across the surface of the object being inspected.

[0005] The inspection robot shown in Patent Document 2 requires, in addition to the inspection device that constitutes the flaw detection mechanism, a travel device including a jack and other robot support mechanisms, a remote device for transmitting power and control signals to the mechanism, and peripheral devices such as transmission cables. This poses the problem of a large scale of inspection-related equipment and preparation work. Furthermore, the remote device is typically located outside the rotating motor, so the need for inspectors to operate the remote device outside the rotating motor and operators to insert, remove, and monitor the robot inside the rotating motor inevitably leads to an increase in the number of operators. Furthermore, the robot has a complex mechanism and is composed of a large number of components, so the inspector's flaw detection experience is different from that of manual ultrasonic flaw detection. In addition to the knowledge and skills of ultrasonic flaw detection, inspectors are also required to possess professional knowledge and skills related to foreign matter management within the rotating motor and robot operation. Mastering this knowledge and skills requires time and expense.

[0006] The present application is made to solve the above-mentioned technical problems, and its purpose is to provide an ultrasonic flaw detection device for rotating motors, which does not require peripheral equipment and has a simple structure, while being able to adjust the fine pressing force of the ultrasonic probe and scan the sliding on the surface of the inspected object, and can reproduce the fine pressing force adjustment performed by a skilled inspector. Technical solutions used to solve technical problems

[0007] The ultrasonic flaw detection device for a rotating electric machine disclosed in the present application is characterized in that it includes: an upper frame, which is connected to the end of one side of a rod-shaped supporting structure; a lower frame, which is connected to the upper frame through a plurality of elastic mechanisms; a holding mechanism, which is arranged on the back side of the surface of the lower frame connected to the elastic mechanism; an ultrasonic probe, which is fixed to the holding mechanism in a detachable manner; an ultrasonic flaw detector, which is arranged on the other side of the supporting structure, controls the ultrasonic wave of the ultrasonic probe and analyzes the received reflected wave; and a three-dimensional driving mechanism, which rotates the ultrasonic probe to follow the movement other than the moving direction of the supporting structure corresponding to the shape of the surface of the inspected object when the ultrasonic probe is in close contact with the surface of the inspected object and the supporting structure is moved linearly. Effects of the Invention

[0008] According to the ultrasonic flaw detection device for rotating motors disclosed in the present application, while requiring no peripheral equipment and having a simple structure, it is possible to correspond to the curvature and slope of the surface of the inspected object through a three-dimensional drive mechanism and enable the ultrasonic probe to smoothly follow, thereby enabling fine adjustment of the pressing force of the ultrasonic probe and sliding scanning on the surface of the inspected object, and can reproduce the fine pressing force adjustment performed by a skilled inspector. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a diagram for explaining an example of the test implementation of the ultrasonic flaw detection device according to the first embodiment. Figure 2 It is a top view of the ultrasonic flaw detection device according to the first embodiment. Figure 3 Observed from arrows A and B Figure 2 Figure 2, (a) is the view observed from arrow A, and (b) is the view observed from arrow B. Figure 4 This is a diagram showing the ultrasonic flaw detection apparatus according to the first embodiment when the cover member is attached. DETAILED DESCRIPTION

[0010] Implementation Method 1 Hereinafter, preferred embodiments of the ultrasonic flaw detection device for a rotating electrical machine of the present application will be described with reference to the accompanying drawings. The same reference numerals are assigned to the same contents and corresponding parts, and detailed description thereof will be omitted.

[0011] Figure 1 This schematic diagram illustrates an example of an ultrasonic flaw detection test being conducted on the assembled rotor and stator of a rotating electrical machine. To inspect the mating portion of, for example, the retaining ring 42 on the rotor 41 without removing the rotor 41 from the stator 31, an inspector 51 approaches the end of the rotor 41 within the rotating electrical machine and inserts the ultrasonic flaw detection device 1 into the gap between the rotor 41 and the stator 31. The ultrasonic probe 9 attached to the tip of the inserted ultrasonic flaw detection device 1 transmits detection results to the ultrasonic flaw detector 21. The inspector 51 scans the ultrasonic flaw detector 21 while confirming the detection results on the display screen provided on the ultrasonic flaw detector.

[0012] Figure 2 This is a side view schematically illustrating the structure of an ultrasonic flaw detection device 1. The ultrasonic flaw detection device 1 comprises a holding mechanism 4 (a collective term for 4a through 4d), a three-dimensional drive mechanism 2, an elastic mechanism 3, and a support mechanism 5. The holding mechanism 4 holds an ultrasonic probe 9, the three-dimensional drive mechanism 2 and the elastic mechanism 3 control the orientation and pressing force of the ultrasonic probe 9, and the support mechanism 5 allows an inspector 51 to operate the ultrasonic probe 9 held by the holding mechanism 4. Each of these structures is described below.

[0013] The supporting mechanism 5 is in the shape of a rod, which supports the ultrasonic probe 9 at one end and has a gripping portion at the other end for the inspector 51 to grasp the supporting mechanism 5 and perform scanning. In order to make the ultrasonic probe 9 close to the surface of the inspected object for scanning, the supporting mechanism 5 fixes the upper frame 7 through the connecting portion 6 installed at one end, rather than the ultrasonic probe 9 being directly supported by the supporting mechanism 5. The upper frame 7 is connected to the lower frame 8 via the elastic mechanism 3 and the three-dimensional driving mechanism 2 described later, and the ultrasonic probe 9 is installed in a detachable manner through the holding mechanism 4 provided on the surface (back side) opposite to the surface of the lower frame 8 opposite to the upper frame 7. In addition, the supporting mechanism 5 is required not to be easily damaged during the flaw detection process of the holding mechanism. For example, if Figure 3 As shown in (a), a convex portion 5a1 is formed at the end of the unit 5a on one side, and a concave portion 5a2 is formed at the end of the unit 5a on the other side opposite to the unit 5a on one side, and a rod type can be used to connect and disassemble the units 5a. With such a structure, the support mechanism 5 can be adjusted to the required length according to the inspection position. By using screws in the connection of each unit 5a, accidental disassembly during flaw detection can be prevented and sufficient strength can be obtained. In addition, in order to facilitate the inspector 51 to operate by hand, a handle made of rubber or other materials can also be provided on the support mechanism 5. By applying a rod type that does not have a complicated mechanism to the support mechanism 5, special education and skill management of the inspector 51 are not required.

[0014] The holding mechanism 4 may also be, for example Figure 2 The screw-type holding mechanism shown is composed of holding plates 4a, 4b and screws 4c. Specifically, the holding plate 4a with screw holes and the holding plate 4b without screw holes are arranged on the lower frame 8 in a facing manner, and the screw 4c is screwed and installed on the holding plate 4a. The ultrasonic probe 9 is clamped by the screw 4c and the holding plate 4b. In addition, in order to prevent the ultrasonic probe 9 from slipping or rotating, an anti-slip member 4d can also be installed at the front end of the screw. By adopting a screw-type holding mechanism, the force holding the ultrasonic probe 9 is not easily weakened during the ultrasonic flaw detection test, so that the ultrasonic probe 9 will not fall off during the flaw detection process. Since the structure is also very simple, the outer dimensions of the holding mechanism 4 can be reduced, so that it can be easily inserted into the narrow space between the rotor 41 and the stator 31. In addition, the ultrasonic probe 9 can be held regardless of the shape of the ultrasonic probe 9 that is changed or replaced according to the flaw detection object.

[0015] Alternatively, a clamping holding mechanism can be adopted to replace the screw holding mechanism. The clamping holding mechanism holds the ultrasonic probe 9 through a toggle-type holding mechanism (Japanese: トグル式). However, in this case, compared with the screw holding mechanism, the structure becomes complex, and thus, the outer dimension of the holding mechanism 4 becomes larger. To solve such a problem, the height dimension of the holding mechanism 4 can be reduced by clamping from the horizontal direction rather than the vertical direction with respect to the inspection surface.

[0016] In order to smoothly follow on the surface of the inspected object (in this embodiment, the outer peripheral surface of the fitting portion of the holding ring 42 and the rotor 41), the ultrasonic probe 9 held by the holding mechanism 4 needs to form an arbitrary angle according to the curvature and slope of the surface of the inspected object. This is achieved by a structure in which the lower frame 8 provided with the holding mechanism 4 can rotate relative to the upper frame 7. On the other hand, since the inspector 51 can operate the linear movement in the front-back, left-right directions by moving the hand via the support mechanism 5, the horizontal movement of the ultrasonic flaw detector 1 itself in the same direction as the movement direction of the support mechanism 5 will instead become an obstacle during flaw detection. For the above reasons, the three-dimensional drive mechanism 2 can also use Figure 3 the swivel structure (Japanese: スイベル構造) shown in (b) of Figure 3 As shown in (b) of

[0017] To suppress the unexpected rotational movement of the three-dimensional drive mechanism 2 and to keep the pressing force of the ultrasonic probe 9 fixed and uniform while controlling the posture of the ultrasonic probe 9 to make the posture control easier, as Figure 3 shown, between the upper frame 7 and the lower frame 8, elastic mechanisms 3 are connected at three locations around the three-dimensional drive mechanism 2. And the rotational movement of the three-dimensional drive mechanism 2 with the axis vertically penetrating the upper frame 7 and the lower frame 8 as the rotation axis is suppressed by the three elastic mechanisms 3. The elastic structure 3 can use various members such as rubber, resin, and various polymer materials according to the required pressing force and the inspection object as the target, but Figure 2 springs are used to illustrate the basic form in

[0018] The three-dimensional drive mechanism 2 and elastic mechanism 3 are required to perform flaw detection in a manner that adapts to the curvature and slope of the inspected object's surface. However, when the curvature and slope of the inspected object's surface are relatively small, the elastic force of the elastic mechanism 3 alone may be sufficient to follow the curvature and slope. In such cases, the three-dimensional drive mechanism 2 can be omitted, and only the elastic mechanism 3 can be used to connect the upper frame 7 and the lower frame 8. This structure reduces the outer diameter of the ultrasonic flaw detection device 1, allowing it to be inserted into even smaller spaces.

[0019] The ultrasonic probe 9 internally contains an ultrasonic transducer. Ultrasonic vibrations from the transducer propagate from the surface of the object being inspected into the interior, and damage within the object is evaluated based on the time it takes for the reflected wave to return and the intensity of the reflected wave. Connected to the outer periphery of the ultrasonic probe 9 are signal lines for transmitting signals to vibrate the ultrasonic transducer, receiving signals for reflected waves, and controlling the ultrasonic transducer. These signal lines are connected to the ultrasonic flaw detector 21 operated by the inspector 51.

[0020] The ultrasonic flaw detector 21 outputs a control signal to control the frequency of the ultrasonic transducer within the ultrasonic probe 9. It also receives reflected wave signals from the ultrasonic probe 9 to analyze the state of damage within the inspected object, displaying the information on a display screen in a manner visually recognizable to the inspector 51. The ultrasonic flaw detector 21 includes a processor and a storage device, which includes volatile storage devices such as random access memory and non-volatile auxiliary storage devices such as flash memory. The processor executes a program input from the storage device to analyze the state of damage within the inspected object, for example, by controlling the frequency of the ultrasonic probe 9 or by reflecting waves. In this case, the program is input from the auxiliary storage device to the processor via the volatile storage device. Alternatively, the processor may output data such as analysis results to the volatile storage device of the storage device, or may store the data in the auxiliary storage device via the volatile storage device.

[0021] The operation of the ultrasonic flaw detection device 1 constructed as described above will be described. An inspector 51 operates the ultrasonic flaw detection device 1 via the support mechanism 5. The support mechanism 5 must be sufficiently long to reach the flaw detection location. However, the space inside a rotating electrical machine, as a workspace, is relatively narrow and limited. Therefore, if the support member 5 is too long, its operability will be impaired. Therefore, the length of the support mechanism 5 is adjusted by separating or connecting the units 5a of the support mechanism 5 according to the distance from the flaw detection location, and then scanning is initiated. At the start of scanning, the inspector 51 manually moves the ultrasonic flaw detection device 1 linearly across the surface of the object being inspected until it reaches the desired flaw detection location. Therefore, the tip of the support mechanism 5 moves within a range that the inspector 51 can visually confirm. Next, the ultrasonic probe 9, attached to the tip of the ultrasonic flaw detection device 1, is brought into close contact with the outer peripheral surface of the mating portion between the retaining ring 42 and the rotor 41, which serves as the flaw detection range. Next, while operating the ultrasonic flaw detector 21 attached to the support mechanism 5 at the inspector's hand, and emitting ultrasonic waves of a set frequency from the ultrasonic probe 9, the inspector 51 moves the hand holding the support mechanism 5 linearly in the front-back, left-right, and right-left directions. This causes the support mechanism 5 to move linearly in the front-back, left-right, and right-left directions, causing the ultrasonic probe 9, attached to the front end of the support mechanism 5, to move over the object being inspected in the same direction as the movement of the support mechanism 5. To prevent the ultrasonic probe 9 from losing its close contact with the object's surface during scanning, the three-dimensional drive mechanism 2 rotates the ultrasonic probe 9 in a manner consistent with the curvature and slope of the object's surface, allowing it to track movement in directions other than linear directions. Furthermore, while the elastic mechanism 3 maintains a constant and uniform pressing force on the ultrasonic probe 9, the ultrasonic probe 9 moves along the surface of the object being inspected. The reflected wave from the ultrasonic probe 9 is converted into an electrical signal and transmitted from the ultrasonic probe 9 to the ultrasonic flaw detector 21. The ultrasonic flaw detector 21 detects the damage based on the electrical signal of the reflected wave received by the ultrasonic flaw detector 21.

[0022] Figure 4 It is shown in Figure 2 This is a side view of the schematic structure of an ultrasonic flaw detection device 1 with a cover member 10 installed. To manage foreign matter within the rotating electrical machine, the cover member 10 is installed to cover the three-dimensional drive mechanism 2 and elastic mechanism 3, which have a large number of components and connections. To ensure that the functions of the three-dimensional drive mechanism 2 and elastic mechanism 3 are not impeded, the cover member can be made of a stretchable material such as rubber or resin, or a material with a stretchable structure such as bellows.

[0023] According to the above-described structure, the ultrasonic flaw detection device 1 has the following effects. (1) Since the ultrasonic waveguide can be inserted into a narrow space such as a gap between a rotor and a stator, an ultrasonic flaw detection test can be performed outside the rotating electrical machine within a visually observable range close to the rotating electrical machine. (2) It is easy to change and replace the ultrasonic probe according to the object to be inspected and the object defects. (3) Despite the simplicity of the mechanism, the ultrasonic probe can be finely adjusted in pressing force and scanned by sliding on the surface of the inspected object, and the fine adjustment of pressing force performed by a skilled inspector can be reproduced. (4) No peripheral equipment is required, which can reduce the equipment, preparation, and personnel required for inspection. (5) The flaw detection feeling is similar to that of the flaw detection test performed manually, and the mechanism is simple, so professional knowledge for operating the inspection device and special training related to skills are not required.

[0024] Although the present application describes exemplary embodiments, various features, modes, and functions described in the embodiments are not limited to application to specific embodiments, and can be applied to the embodiments alone or in various combinations. Therefore, numerous modifications not shown in the examples are contemplated within the technical scope disclosed in this specification, including, for example, modifying at least one component, adding at least one component, or omitting at least one component. Explanation of symbols

[0025] 1. Ultrasonic flaw detection device; 2. Three-dimensional driving mechanism; 3. Elastic mechanism; 4. Holding mechanism; 5. Support mechanism; 6. Connecting portion; 7. Upper frame; 8. Lower frame; 9. Ultrasonic probe; 10. Cover member.

Claims

1. An ultrasonic flaw detection device for a rotating electrical machine, characterized in that: include: An upper frame connected to an end of one side of a rod-shaped supporting structure; a lower frame connected to the upper frame via a plurality of elastic mechanisms; a holding mechanism disposed on the back side of a surface of the lower frame connected to the elastic mechanism; an ultrasonic probe fixed to the holding mechanism in a detachable manner; an ultrasonic flaw detector disposed on the other side of the supporting structure, controlling the ultrasonic wave of the ultrasonic probe and analyzing the received reflected wave; and a three-dimensional driving mechanism, which rotates the ultrasonic probe to follow a movement other than a moving direction of the supporting structure corresponding to the shape of the surface of the object to be inspected, while the ultrasonic probe is in close contact with the surface of the object to be inspected and the supporting structure is moved linearly.

2. The ultrasonic flaw detection device for a rotating electrical machine according to claim 1, wherein: The three-dimensional driving mechanism is a rotating structure composed of a support body fixed to the upper frame and a member having one end rotatably fitted in the support body and the other end fixed to the lower frame.

3. The ultrasonic flaw detection device for a rotating electrical machine according to claim 2, wherein: The three-dimensional drive mechanism is arranged to be surrounded by the plurality of elastic mechanisms, and the plurality of elastic mechanisms suppress movement of the three-dimensional drive mechanism in a rotational direction about an axis perpendicularly passing through the upper frame and the lower frame.

4. The ultrasonic flaw detection device for a rotating electrical machine according to any one of claims 1 to 3, characterized in that: The holding mechanism is configured such that a first holding plate with screw holes and a second holding plate without screw holes are arranged on the lower frame in a spaced-apart manner and face each other, and the ultrasonic probe is clamped by screws screwed into the first holding plate and the second holding plate.

5. The ultrasonic flaw detection device for a rotating electrical machine according to any one of claims 1 to 4, characterized in that: The upper frame, the lower frame, the three-dimensional driving mechanism, and the elastic mechanism are covered by a cover member.

6. The ultrasonic flaw detection device for a rotating electrical machine according to any one of claims 1 to 5, characterized in that: The support structure is configured to be able to adjust its length according to a flaw detection position of the inspection object by separating and connecting a plurality of unit members.

Images