Ultrasonic flaw detection device for rotating electrical machinery

Abstract

The present invention is constituted from a holding mechanism (4) that is insertable in a gap between a rotor (41) and a stator (31) of a rotary electric machine and in which an ultrasonic probe (9) is easily replaced and changed, a three-dimensional drive mechanism (2) that follows the curvature and slope of a surface to be inspected, an elastic mechanism (3) for performing pressing force adjustment of the ultrasonic probe (9), and a support structure (5) for carrying out of a flaw detection operation by an inspector (51). The three-dimensional drive mechanism (2) causes the ultrasonic probe (9) to smoothly follow the curvature and slope of the surface to be inspected, and it is thereby possible to finely adjust the pressing force of the ultrasonic probe (9) and cause the ultrasonic probe (9) to scan smoothly over the surface to be inspected, and to reproduce a fine pressing force adjustment performed by a trained inspector (51).

Description

Technical Field

[0001] This application relates to an ultrasonic flaw detector for rotating electrical machines.

Background Art

[0002] In the maintenance and inspection of rotating electrical machines, conventionally, it has been the mainstream to remove the rotor from the stator and inspect the wedge portion and retaining ring portion etc. in a disassembled state. However, the operation of removing the rotor requires a long downtime and high costs. Therefore, methods for inspecting rotating electrical machines without removing the rotor from the stator have been proposed. For example, in Patent Document 1, a probe-integrated ultrasonic flaw detector and an ultrasonic flaw detection method equipped with an ultrasonic probe and a probe drive mechanism inside the main body are disclosed. Also, in Patent Document 2, an inspection robot that can be operated from outside the rotating electrical machine by a remote device is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The flaw detection apparatus described in Patent Document 1 is an ultrasonic flaw detection apparatus with an integrated probe. Because the ultrasonic probe is connected to the probe drive mechanism and mounted inside the main body, there is a problem in that it is not easy to change or replace the ultrasonic probe to match the object under inspection and the target defect. Furthermore, the pressing force of the ultrasonic probe against the object under inspection is controlled by the probe drive mechanism, making it difficult to reproduce the fine adjustment of pressing force performed by a skilled inspector. In addition, since the ultrasonic vibrations emitted from the ultrasonic probe are transmitted to the object under inspection via a gel-like elastic member, the ultrasonic probe and the elastic member are bonded together, making it impossible to reproduce the scanning of the ultrasonic probe by sliding it across the surface of the object under inspection, as performed by a skilled inspector.

[0005] The inspection robot described in Patent Document 2 requires not only an inspection device that forms the flaw detection mechanism, but also a traveling device including a robot support mechanism such as a pantograph jack, a remote device for sending power and control signals to the mechanism, and peripheral devices such as transmission cables. This resulted in a large-scale inspection process involving equipment and preparation. Furthermore, since the remote device is generally installed outside the rotating electric machine, an inspector is required to operate the remote device outside the machine, and another worker is required to insert, remove, and monitor the robot inside the machine, inevitably increasing the number of personnel required. Moreover, because the robot has a complex mechanism, it is composed of numerous parts, and the inspector's flaw detection skills differ from those of manual ultrasonic testing. Inspectors are required to have specialized knowledge and skills regarding foreign object management inside the rotating electric machine and robot operation, in addition to their knowledge and skills in ultrasonic testing, and acquiring this knowledge and skills is time-consuming and costly.

[0006] This invention was made to solve the above-mentioned problems, and aims to provide an ultrasonic flaw detection device for rotating electrical machinery that does not require peripheral equipment, has a simple configuration, and is capable of fine adjustment of the pressing force of the ultrasonic probe and scanning by sliding it over the surface of the object under inspection, thereby reproducing the fine pressing force adjustment performed by a skilled inspector. [Means for solving the problem]

[0007] The ultrasonic flaw detection device for rotating electric machinery disclosed herein is connected to one end of a rod-shaped support structure, A flat plate having a plane in the direction in which the support structure extends Upper frame, upper frame One end is attached to a plane having a connection point to the end, and it extends in a direction perpendicular to the plane. Multiple elastic mechanisms The upper frame has a surface facing the plane, and the other ends of multiple elastic mechanisms are attached to this surface. A lower frame, a holding mechanism disposed on the back of the surface connected to the elastic mechanism of the lower frame, an ultrasonic probe detachably fixed to the holding mechanism, and an ultrasonic flaw detector positioned on the other side of the support structure, which controls the ultrasonic waves of the ultrasonic probe and analyzes the received reflected waves. It is installed in the space formed by multiple elastic mechanisms and an upper frame and a lower frame connected by elastic mechanisms. When the ultrasonic probe is placed in close contact with the surface of the object being inspected and the support structure is moved in a straight line, The lower frame is made capable of rotational movement so that it can take any angle relative to the upper frame. Equipped with a three-dimensional drive mechanism. The three-dimensional drive mechanism, by having rotational movement with respect to an axis perpendicular to the upper and lower frames as the axis of rotation suppressed by the multiple elastic mechanisms, rotates the ultrasonic probe in accordance with movements other than horizontal, which are in the same direction as the movement direction of the support structure corresponding to the shape of the surface of the object being inspected. It is characterized by the following: [Effects of the Invention]

[0008] The ultrasonic flaw detection apparatus for rotating electric machinery disclosed herein does not require peripheral equipment and has a simple configuration. However, by using a three-dimensional drive mechanism to smoothly follow the curvature and gradient of the surface of the object under inspection, it is possible to adjust the minute pressing force of the ultrasonic probe and scan by sliding it over the surface of the object under inspection, thereby replicating the minute pressing force adjustment performed by a skilled inspector. [Brief explanation of the drawing]

[0009] [Figure 1] This figure illustrates an example of a test procedure performed by an ultrasonic flaw detection device according to Embodiment 1. [Figure 2] This is a plan view of the ultrasonic flaw detection apparatus according to Embodiment 1. [Figure 3] Figure 2 is viewed from arrows A and B, respectively, with (a) being the view from arrow A and (b) being the view from arrow B. [Figure 4]It is a diagram showing the state when the cover of the ultrasonic flaw detector according to Embodiment 1 is attached.

Embodiments for Carrying Out the Invention

[0010] Embodiment 1. Hereinafter, a preferred embodiment of the ultrasonic flaw detector for a rotating electric machine according to the present application will be described with reference to the drawings. Note that the same reference numerals are assigned to the same contents and corresponding parts, and detailed descriptions thereof are omitted.

[0011] FIG. 1 is a schematic diagram showing an example at the time of performing an ultrasonic flaw detection test in a state where a rotor and a stator of a rotating electric machine are assembled. When inspecting, for example, the fitting portion between the rotor 41 and the retaining ring 42 without pulling out the rotor 41 from the stator 31, the inspector 51 enters near the end of the rotor 41 inside the rotating electric machine and inserts the ultrasonic flaw detector 1 into the gap between the rotor 41 and the stator 31. The flaw detection result of the ultrasonic probe 9 attached to the tip of the inserted ultrasonic flaw detector 1 is transmitted to the ultrasonic flaw detector 21, and the inspector 51 can scan the ultrasonic probe 9 while confirming the flaw detection result on the display provided on the ultrasonic flaw detector.

[0012] FIG. 2 is a side view showing a schematic configuration of the ultrasonic flaw detector 1. It is composed of a holding mechanism 4 (a general term for 4a to 4d) for holding the ultrasonic probe 9, a three-dimensional drive mechanism 2 and an elastic mechanism 3 for controlling the orientation and pressing force of the ultrasonic probe 9, and a support mechanism 5 for the inspector 51 to operate the ultrasonic probe 9 held by the holding mechanism 4. Each of the following configurations will be described.

[0013] The support mechanism 5 is rod-shaped, supporting the ultrasonic probe 9 at one end and having a gripping portion at the other end that allows the inspector 51 to grasp the support mechanism and scan. In order to scan with the ultrasonic probe 9 in close contact with the surface of the object to be inspected, the support mechanism 5 does not directly support the ultrasonic probe 9, but rather the support mechanism 5 fixes the upper frame 7 with a connecting portion 6 attached to one end. The upper frame 7 is connected to the lower frame 8 via an elastic mechanism 3 and a three-dimensional drive mechanism 2, which will be described later, and the ultrasonic probe 9 is detachably attached by a holding mechanism 4 disposed on the side (back) of the lower frame 8 opposite to the side facing the upper frame 7. Furthermore, the support mechanism 5 , search It is required that the device not easily break during inspection. For example, as shown in Figure 3(a), a protrusion 5a1 may be formed at the end of one unit 5a, and a recess 5a2 may be formed at the end of the other unit 5a facing the first unit 5a, so that each unit 5a can be connected and detached using a rod type. With such a configuration, the support mechanism 5 can be adjusted to the required length according to the inspection position. By using screws to connect each unit 5a, accidental detachment during flaw detection can be prevented and sufficient strength can be obtained. In addition, the support mechanism 5 may be equipped with a grip made of a material such as rubber so that it is easy for the inspector 51 to hold and operate. By applying a rod type that does not have a complex mechanism to the support mechanism 5, the need for special training of the inspector 51 and other skill management is eliminated.

[0014] The holding mechanism 4 may be, for example, a screw-type holding mechanism including holding plates 4a and 4b and a screw 4c as shown in FIG. 2. Specifically, the holding plate 4a with a screw hole and the holding plate 4b without a screw hole are arranged on the lower frame 8 so as to face each other, and the screw 4c is screwed into the holding plate 4a. The ultrasonic probe 9 is sandwiched between 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 4d may be attached to the tip of the screw. By adopting a screw-type holding mechanism, the force for holding the ultrasonic probe 9 during the ultrasonic flaw detection test is not easily loosened, and the ultrasonic probe 9 does not fall off during the flaw detection. Since the structure is 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. Furthermore, the ultrasonic probe 9 can be held regardless of the shape of the ultrasonic probe 9 that is changed and replaced according to the flaw detection target.

[0015] In addition, instead of the screw-type holding mechanism, a clamp-type holding mechanism that clamps the ultrasonic probe 9 by a toggle-type holding mechanism may be used. However, in this case, since the structure becomes more complicated than the screw-type holding mechanism, the outer dimensions of the holding mechanism 4 become larger. In order to solve such a problem, instead of clamping from the direction perpendicular to the flaw detection surface, it may be clamped from the horizontal direction to reduce the height dimension of the holding mechanism 4.

[0016] In order to smoothly follow the surface of the object under inspection (in this embodiment, the outer surface of the fitting portion of the retaining ring 42 with the rotor 41), the ultrasonic probe 9 held by the retaining mechanism 4 needs to take an arbitrary angle that matches the curvature and gradient of the surface of the object under inspection. This is achieved by configuring the lower frame 8, on which the retaining mechanism 4 is located, to be rotatable relative to the upper frame 7. On the other hand, since the inspector 51 can control linear movement in the forward, backward, left, and right directions by moving their hand via the support mechanism 5, horizontal movement in the same direction as the movement of the support mechanism 5 of the ultrasonic flaw detection device 1 itself would actually be an obstacle when performing flaw detection. For these reasons, the three-dimensional drive mechanism 2 may use a swivel structure as shown in Figure 3(b). Specifically, in Figure 3(b), a rotatably held member 2b and a lower frame 8 are connected within a support structure 2a supported by the upper frame 7. By enabling the rotational movement of the lower frame 8 so that it can take any angle relative to the upper frame 7, the ultrasonic probe 9 held by the holding mechanism 4 disposed on the back of the lower frame 8 can rotate freely.

[0017] To suppress unintended rotational movement of the three-dimensional drive mechanism 2, control the attitude of the ultrasonic probe 9, and maintain a constant and uniform pressing force on the ultrasonic probe 9 to facilitate attitude control, elastic mechanisms 3 are connected at three locations around the three-dimensional drive mechanism 2 between the upper frame 7 and the lower frame 8, as shown in Figure 3. The rotational movement of the three-dimensional drive mechanism 2, which has an axis perpendicular to the upper frame 7 and the lower frame 8 as its axis of rotation, is suppressed by the three elastic mechanisms 3. Depending on the required pressing force and the object being inspected, various materials such as rubber, resin, and various polymer materials can be used for the elastic mechanisms 3, but in Figure 2, a spring is used to illustrate the basic form. The spring engages with fasteners formed on the upper frame 7 and the lower frame 8. Furthermore, the number of connected elastic mechanisms 3 is not limited to three.

[0018] A three-dimensional drive mechanism 2 and an elastic mechanism 3 are necessary to perform flaw detection in accordance with the curvature and gradient of the surface of the object under inspection. However, if the curvature and gradient of the surface of the object under inspection are small, the elastic force of the elastic mechanism 3 alone may be sufficient to follow the curvature. In this case, the three-dimensional drive mechanism 2 may be omitted, and the upper frame 7 and lower frame 8 may be connected using only the elastic mechanism 3. This configuration allows the outer diameter of the ultrasonic flaw detection device 1 to be reduced, making it possible to insert it into narrower spaces.

[0019] The ultrasonic probe 9 is equipped with an ultrasonic transducer inside and propagates ultrasonic vibrations from the transducer from the surface to the interior of the object under inspection. It evaluates defects present in the object under inspection based on the time it takes for the reflected wave to return and the intensity of the reflected wave. Signal lines for transmitting signals to vibrate the ultrasonic transducer, signal lines for receiving reflected wave signals, and signal lines for controlling the ultrasonic transducer are connected to the outer circumference of the ultrasonic probe 9. 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 in the ultrasonic probe 9, and also receives the reflected wave signal from the ultrasonic probe 9 to analyze the condition of the flaw in the object being inspected, and displays it on a display so that the inspector 51 can see it. The ultrasonic flaw detector 21 consists of a processor and a memory device, the memory device comprising a volatile memory device such as random access memory and a non-volatile auxiliary memory device such as flash memory. The processor executes a program input from the memory device to perform, for example, frequency control of the ultrasonic probe 9 or analysis of the condition of the flaw in the object being inspected using reflected waves. In this case, the program is input from the auxiliary memory device to the processor via the volatile memory device. The processor may also output data such as the analysis results to the volatile memory device of the memory device, or it may save the data to the auxiliary memory device via the volatile memory device.

[0021] The operation of the ultrasonic flaw detection device 1 configured in this way will now be explained. The inspector 51 operates the ultrasonic flaw detection device 1 through the support mechanism 5. The support mechanism 5 needs to be long enough to reach the flaw detection area, but the working space inside the rotating electric machine is narrow and limited, so if it is longer than necessary, it will be difficult to operate. Therefore, the support mechanism 5 separates or connects units 5a according to the distance to the flaw detection area, adjusts the length of the support mechanism 5, and then starts scanning. When scanning starts, the inspector 51 manually moves the ultrasonic flaw detection device 1 in a straight line over the surface of the object under inspection to reach the desired flaw detection area. Therefore, the movement of the tip of the support mechanism 5 is within the range visible to the inspector 51. Then, the ultrasonic probe 9 attached to the tip of the ultrasonic flaw detection device 1 is brought into close contact with the outer surface of the fitting portion between the retaining ring 42 and the rotor 41, which is the flaw detection area. Subsequently, the inspector 51 operates the ultrasonic flaw detector 21 attached to the support mechanism 5 in their hand, emitting ultrasonic waves of a set frequency from the ultrasonic probe 9. By moving the hand holding the support mechanism 5 linearly back and forth and left and right, the inspector 51 moves the support mechanism 5 linearly back and forth and left and right, causing the ultrasonic probe 9 attached to the tip of the support mechanism 5 to move over the object under inspection in the same direction as the movement of the support mechanism 5. To prevent the ultrasonic probe from losing contact with the surface of the object under inspection during scanning, the three-dimensional drive mechanism 2 rotates the ultrasonic probe 9 in accordance with the curvature and gradient of the surface of the object under inspection, allowing it to follow movement in directions other than linear. The elastic mechanism 3 then moves the ultrasonic probe 9 along the surface of the object under inspection while maintaining a constant and uniform pressing force. The reflected waves from the ultrasonic probe 9 are converted into electrical signals and transmitted to the ultrasonic flaw detector 21, which detects the condition of the defect based on the electrical signals of the reflected waves received by the ultrasonic flaw detector 21.

[0022] Figure 4 is a side view showing a schematic configuration of the ultrasonic flaw detection device 1 in Figure 2 with the cover 10 attached. For the purpose of controlling foreign matter inside the rotating electric machine, the cover 10 is attached so as to cover the three-dimensional drive mechanism 2 and the elastic mechanism 3, which have a particularly large number of parts and connections. The cover material may be made of an elastic material such as rubber and resin, or a material with an expandable structure such as a bellows, so as not to hinder the function of the three-dimensional drive mechanism 2 and the elastic mechanism 3.

[0023] With the above configuration, the ultrasonic flaw detection device 1 has the following effects. (1) Because it is designed to be inserted into narrow spaces such as the gap between the rotor and the stator, ultrasonic flaw detection tests can be performed outside the rotating electrical machine, within a visible range close to the rotating electrical machine. (2) The ultrasonic probe can be easily changed and replaced to suit the object being inspected and the target defect. (3) Despite its simple mechanism, it allows for fine adjustment of the ultrasonic probe's pressing force and scanning by sliding it across the surface of the object being inspected, thus replicating the fine pressure adjustments performed by skilled inspectors. (4) Peripheral equipment is not required, and the amount of equipment, preparation work, and personnel involved in inspections can be reduced. (5) Because the detection sensation is similar to that of manually performed ultrasonic testing and the mechanism is simple, special training regarding specialized knowledge and skills for operating the inspection device is not required.

[0024] Although this application describes exemplary embodiments, the various features, aspects, and functions described in the embodiments are not limited to the application of any particular embodiment, but can be applied individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the technology disclosed in this specification. These include, for example, modifications, additions, or omissions of at least one component. [Explanation of symbols]

[0025] 1: Ultrasonic flaw detection device, 2: Three-dimensional drive mechanism, 3: Elastic mechanism, 4: Holding mechanism, 5: Support mechanism, 6: Connection part, 7: Upper frame, 8: Lower frame, 9: Ultrasonic probe, 10: Cover.

Claims

1. A flat upper frame connected to one end of a rod-shaped support structure and having a plane in the direction in which the support structure extends; a plurality of elastic mechanisms, one end of which is attached to the plane having a connection portion with the end of the upper frame and extending in a direction perpendicular to the plane; a lower frame having a surface facing the plane of the upper frame and to which the other ends of the plurality of elastic mechanisms are attached; a holding mechanism disposed on the back of the surface of the lower frame connected to the elastic mechanisms; an ultrasonic probe detachably fixed to the holding mechanism; an ultrasonic flaw detector disposed on the other side of the support structure for controlling the ultrasonic waves of the ultrasonic probe and analyzing the received reflected waves; and the plurality of elastic mechanisms. An ultrasonic flaw detection device for a rotating electric machine, comprising: a three-dimensional drive mechanism mounted in the space formed by the upper frame and the lower frame connected by the elastic mechanism, which allows the lower frame to rotate so that it can take any angle with respect to the upper frame when the ultrasonic probe is in close contact with the surface of the object to be inspected and the support structure is moved linearly, wherein the three-dimensional drive mechanism is characterized in that, by suppressing rotational movement in the direction of rotation with an axis perpendicularly passing through the upper frame and the lower frame as the axis of rotation, the ultrasonic probe is rotated in accordance with movements other than horizontal movements in the same direction as the movement direction of the support structure according to the shape of the surface of the object to be inspected.

2. The ultrasonic flaw detection apparatus for a rotating electric machine according to claim 1, characterized in that the three-dimensional drive mechanism is a swivel structure comprising a support fixed to the upper frame and a member whose one end is loosely fitted to the support so as to be rotatable and whose other end is fixed to the lower frame.

3. The ultrasonic flaw detection apparatus for a rotating electric machine according to claim 1 or 2, characterized in that the holding mechanism has a structure in which a first holding plate with a screw hole and a second holding plate without a screw hole are disposed on the lower frame opposite to each other with a gap in between, and the ultrasonic probe is held between a screw screwed into the first holding plate and the second holding plate.

4. The ultrasonic flaw detection apparatus for a rotating electric machine according to claim 1 or 2, characterized in that the upper frame, the lower frame, the three-dimensional drive mechanism, and the elastic mechanism are covered by a cover.

5. The ultrasonic flaw detection apparatus for a rotating electric machine according to claim 1 or 2, characterized in that the support structure is configured to be adjustable in length according to the flaw detection position of the object under inspection by separating and connecting a plurality of unit-type members.

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