AC motor inspection device and AC motor inspection method

Abstract

To provide an AC motor inspection device and an AC motor inspection method capable of accurately inspecting warpage of a wedge without extracting a rotor.SOLUTION: An AC motor inspection device includes a warpage measuring apparatus that comprises: a striking device applying strike on a wedge fixing a stator of an AC motor; a first measuring apparatus measuring an acceleration speed of the strike applied by the striking device; a second measuring apparatus measuring an acceleration speed of the wedge; and a housing storing the striking device, the first measuring apparatus and the second measuring apparatus. The striking device includes: a leaf spring; a cam rotating to push up the leaf spring for elastic deformation; a rotation application device rotating the cam; and a presser transferring strike applied by the leaf spring to the wedge. The housing includes a magnet wheel connected via an elastic body to the housing and capable of being stored within the housing, and an electromagnet adsorbing the housing onto an inner peripheral surface of the stator.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an inspection device for an AC motor and an inspection method for an AC motor. [Background technology]

[0002] Conventionally, there is known a technique for inspecting whether a wedge that mechanically fixes a coil inserted in a slot of a stator in an AC motor is loose. For example, Patent Document 1 discloses a wedge measuring device that includes a measuring head that can be inserted into a gap between a stator, which is the stator of a rotating electric machine, and a rotor, which is the rotor, and detects the pressing state of the coil of the wedge inserted into the slot, and a moving mechanism that can move the measuring head in the longitudinal direction (axial direction) and circumferential direction of the stator. Patent Document 2 also discloses a wedge impact device for a rotating electric machine that is inserted into the gap between the rotor and stator of the rotating electric machine and impacts a wedge (wedge) of the rotating electric machine, and a wedge inspection system that inspects the wedge using an impact input waveform when the wedge is impacted by the wedge impact device and a vibration waveform of the wedge. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-214244 [Patent Document 2] Patent No. 6250241 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a technique for inspecting the looseness of the wedge without pulling out the rotor, but the wedge measuring device is not self-propelled, and uses a rail parallel to the axis of the motor and a moving wire as a mechanism for moving the measuring head in the axial direction of the motor. Therefore, when mounting the wedge measuring device on the motor, it is necessary to remove the parts from at least one end of the rail, insert the rail between the rotor and stator of the motor, and then reattach the parts to the end of the rail from which the parts were previously removed, which is a cumbersome task. In addition, this rail serves as a guide for moving the wedge measuring device in a desired direction, and also serves to hold the wedge measuring device. Therefore, the rail needs to be sturdy to withstand the load of the wedge measuring device. Therefore, there is a concern that the rail will bend under its own weight, causing a positional shift in the measurement position on the rail where the wedge measuring device measures the looseness of the wedge, and it may not be possible to inspect the looseness of the wedge with high accuracy.

[0005] Patent Document 2 also discloses a technique for inspecting the looseness of the wedge without pulling out the rotor. This requires a fixed fulcrum to rotatably support the striking arm, and further requires the provision of an energy supplying section and an absorbing section in addition to the striking arm and the striking section, which inevitably complicates the mechanism of the wedge striking device. This increases the weight of the wedge striking device and makes the state of adhesion of the wedge striking device to the inner peripheral surface of the stator unstable, which results in unstable measurement data and the inability to accurately inspect the looseness of the wedge.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide an inspection device for an AC motor and an inspection method for an AC motor that can accurately inspect for loosening of wedges without pulling out the rotor. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, an inspection device for an AC motor according to the present invention has a looseness measuring device including an impact device that impacts a wedge that fixes a stator of an AC motor, a first measuring device that measures the acceleration of the impact applied by the impact device, a second measuring device that measures the acceleration of the wedge, and a housing that accommodates the impact device, the first measuring device, and the second measuring device, wherein the impact device includes a leaf spring, a cam that rotates to push up and elastically deform the leaf spring, a rotation imparting device that rotates the cam, and a contact pin that transmits the impact applied from the leaf spring to the wedge, and the housing is connected to the housing via an elastic body, and includes a magnet wheel that can be stored inside the housing, and an electromagnet that can attract the housing to the inner surface of the stator.

[0008] In addition, the inspection device for an AC motor according to the present invention is characterized in that, in the above invention, it has a calculation device that calculates an acceleration ratio, which is the ratio of the acceleration of the wedge to the acceleration of the impact applied to the wedge by the impact device, and a determination device that determines the degree of loosening of the wedge using the calculation result of the calculation device.

[0009] Furthermore, the method for inspecting an AC motor according to the present invention is characterized in that the looseness measuring device possessed by the inspection apparatus for an AC motor of the above-mentioned invention is inserted into a gap formed between the rotor and the stator of the AC motor, an impact is applied to the wedge using the looseness measuring device, and the degree of looseness of the wedge is determined from the relationship between the acceleration of the impact and the acceleration of the wedge.

[0010] Furthermore, the method of inspecting an AC motor according to the present invention is characterized in that in the above invention, the method of determining the degree of loosening of the wedge includes a step of determining a peak-held value A1 after applying a low-pass filter to the acceleration waveform of the impact applied to the wedge, a step of determining a peak-held value A2 after applying a low-pass filter to the acceleration waveform of the wedge, a step of calculating the ratio A2 / A1 for each impact to determine an acceleration ratio, a step of performing multiple impacts at each measurement location and calculating an average value after eliminating data related to the initial impacts, and a step of determining the degree of loosening of the wedge from a previously prepared relationship between the acceleration ratio and the degree of loosening based on the average acceleration ratio thus determined. Effect of the Invention

[0011] The inspection device and the inspection method for an AC motor according to the present invention have the advantage that it is possible to accurately inspect for loosening of the wedge without pulling out the rotor. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of an inspection device according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a state in which the looseness measuring device is inserted into a gap formed between a stator and a rotor of an AC motor. [Diagram 3] FIG. 3 is a diagram showing a part of a cross section of a stator of an AC motor. [Figure 4] FIG. 4 is a side view showing a schematic configuration of the looseness measurement device according to the embodiment. [Diagram 5] FIG. 5 is a top view showing a schematic configuration of the looseness measurement device according to the embodiment. [Figure 6] FIG. 6 is a diagram showing a state in which the leaf spring is elastically deformed by the cam. [Figure 7] FIG. 7 is a diagram showing the state in which the striking portion of the leaf spring strikes the striker. [Figure 8] FIG. 8 is a side view showing a schematic configuration of the second measuring device. [Figure 9] FIG. 9 is a diagram showing the slack measuring device when the electromagnet is not activated. [Figure 10] FIG. 10 is a diagram showing the looseness measuring device in a state where the electromagnet is activated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an inspection device for an AC motor and an inspection method for an AC motor according to the present invention will be described. Note that the present invention is not limited to the embodiment.

[0014] FIG. 1 is a block diagram showing a schematic configuration of an inspection device 10 according to an embodiment. As shown in FIG. 1, the inspection device 10 according to an embodiment is a device for inspecting an AC motor, specifically, inspecting the degree of looseness of a wedge provided in a stator of an AC motor, and includes a looseness measurement device 1, a control device 7, a calculation device 8, and a determination device 9. The looseness measurement device 1 is a device for measuring the looseness of the wedge by striking the wedge, and includes a striking device 2, a first measuring device 3, a second measuring device 4, and a suction device 5. The looseness measurement device 1, the striking device 2, the first measuring device 3, the second measuring device 4, the suction device 5, the control device 7, the calculation device 8, and the determination device 9 will be described in detail later.

[0015] Fig. 2 is a diagram showing a state in which the slack measurement device 1 is inserted into a gap formed between the stator 110 and rotor 120 of the AC motor 100. As shown in Fig. 2, in the inspection device 10 according to the embodiment, the rotor 120 of the AC motor 100 is not pulled out, but the slack measurement device 1 is inserted into the gap formed between the stator 110 and rotor 120 of the AC motor 100 to inspect the degree of slackness of wedges 112 (see Fig. 3), which will be described later, provided on the stator 110.

[0016] 3 is a diagram showing a part of a cross section of a stator 110 of an AC motor 100. As shown in FIG. 3, in the stator 110 of the AC motor 100, a coil 113 is arranged in a slot 114 formed in an iron core 111. The coil 113 is pressed by a wedge 112 installed in an opening of the slot 114, so that the coil 113 is mechanically fixed. The wedge 112 may be made of, for example, epoxy resin. In FIG. 3, the area above the iron core 111 and the wedge 112 is a part of the space between the stator 110 and the rotor 120.

[0017] Here, the wedge 112 loosens due to wear caused by thermal deterioration of an insulator (not shown) electrically insulating the iron core 111 and the coil 113, mechanical wear caused by electromagnetic vibration, etc., as a result of long-term use of the AC motor 100, and the coil 113 is not sufficiently fixed. Therefore, if the vibration of the coil 113 generated during operation of the AC motor 100 becomes large, the insulator (not shown) electrically insulating the iron core 111 and the coil 113 may be mechanically damaged, causing an electrical short circuit. Therefore, in the inspection device 10 according to the embodiment, the degree of looseness of the wedge 112 is inspected using the looseness measurement device 1.

[0018] FIG. 4 is a side view showing a schematic configuration of the looseness measurement device 1 according to the embodiment. FIG. 5 is a top view showing a schematic configuration of the looseness measurement device 1 according to the embodiment. As shown in FIGS. 4 and 5, the looseness measurement device 1 according to the embodiment includes an impact device 2, a first measurement device 3, a second measurement device 4, a suction device 5, and a housing 6 that houses these components of the looseness measurement device 1. The housing 6 has a size that allows it to enter a gap formed between the rotor 120 and the stator 110 of the AC motor 100, and is inserted into the gap so that a top plate portion 6a of the housing 6 is located on the rotor 120 side and a bottom plate portion 6b of the housing 6 is located on the stator 110 side.

[0019] The impact device 2 is a device that impacts the wedge 112 provided on the stator 110. The impact device 2 includes a leaf spring 21, a cam 22 that lifts the leaf spring 21 by rotating to elastically deform it, a rotation imparting device 23 such as a motor that rotates the cam 22, and a contact pin 24 that transmits the impact from the leaf spring 21 to the wedge 112. One end of the leaf spring 21 in the longitudinal direction is a fixed end fixed on a fixed base 25, and the other end of the leaf spring 21 in the longitudinal direction is a free end. A convex impact portion 21a that protrudes toward the contact pin 24 at a position corresponding to the contact pin 24 is provided on the surface of the leaf spring 21 facing the contact pin 24 through an opening 61 formed in the bottom plate portion 6b of the housing 6. In addition, a cam contact portion 21b that can contact a cam surface formed on the outer periphery of the cam 22 is provided on the tip portion of the free end side of the leaf spring 21. The contact pin 24 is connected to the bottom plate portion 6b of the housing 6 (the edge of the opening 61) via an elastic body 26 at a position where the striking portion 21a of the leaf spring 21 can strike through an opening 61 formed in the bottom plate portion 6b of the housing 6. The striking portion 21a and the contact pin 24 need only be harder than the wedge 112. As the material for the striking portion 21a and the contact pin 24, for example, various metal materials can be used.

[0020] Fig. 6 is a diagram showing a state in which the leaf spring 21 is elastically deformed by the cam 22. Fig. 7 is a diagram showing a state in which the impact portion 21a of the leaf spring 21 impacts the contact pin 24. As shown in Fig. 6, the impact device 2 rotates the cam 22 by the rotation imparting device 23, so that the cam contact portion 21b is pushed up by the cam 22, elastically deforming the leaf spring 21. Then, as shown in Fig. 7, the rotation imparting device 23 further rotates the cam 22 to release the cam contact portion 21b from the cam 22, generating an impact force due to the elastic force of the leaf spring 21, and the impact portion 21a of the leaf spring 21 impacts the contact pin 24.

[0021] 3, the inner peripheral surface 111a of the core 111 forming the inner peripheral surface 110a of the stator 110 and the inner peripheral surface 112a of the wedge 112 do not necessarily have a constant positional relationship. Therefore, in the case of a configuration in which the striking portion 21a of the leaf spring 21 directly strikes the wedge 112, there is a concern that the moving distance from when the cam contact portion 21b of the leaf spring 21 is released from the cam 22 until the striking portion 21a of the leaf spring 21 strikes the wedge 112 may vary greatly. Such a large variation in the moving distance may cause variations in the measurement results.

[0022] Therefore, in the looseness measuring device 1 according to the embodiment, a structure is adopted in which the impact portion 21a of the leaf spring 21 does not directly contact and impact the wedge 112, but rather the impact portion 21a of the leaf spring 21 impacts the contact pin 24 that has been brought into contact with the wedge 112 in advance, and impacts the wedge 112 via the contact pin 24. This makes it possible to suppress the influence of large fluctuations in the travel distance until the impact portion 21a of the leaf spring 21 strikes the wedge 112, as described above. Therefore, in the looseness measuring device 1 according to the embodiment, it is possible to apply a stable impact force to the wedge 112 by the impact device 2, and to suppress variations in the measurement results caused by large fluctuations in the travel distance.

[0023] The first measuring device 3 provided in the slack measuring device 1 according to the embodiment is a device that measures the acceleration of the impact given by the impact device 2 to the wedge 112, and is configured using, for example, an accelerometer.

[0024] An accelerometer included in the first measuring device 3 is attached near the hitting portion 21a of the leaf spring 21 to measure the acceleration of the hitting portion 21a.

[0025] The second measuring device 4 provided in the looseness measuring device 1 according to the embodiment is a device that measures the acceleration (acceleration of response) of the wedge 112, which is the object struck by the striking device 2, and is configured using, for example, an accelerometer.

[0026] FIG. 8 is a side view showing a schematic configuration of the second measuring device 4. As shown in FIG. 8, the second measuring device 4 is composed of a contact member 41, resin members 42a and 42b, anti-vibration rubbers 43a, 43b, 43c, and 43d, an accelerometer 44, and the like. The contact member 41 is disposed at a position corresponding to the wedge 112 through an opening 62 formed in the bottom plate portion 6b of the housing 6. The contact member 41 has a convex shape in which the side facing the wedge 112 protrudes toward the wedge 112. The contact member 41 is held by being sandwiched and compressed by two resin members 42a and 42b. As a method of holding the contact member 41 by sandwiching and compressing it with the resin members, in addition to a method of sandwiching the contact member 41 between two resin members 42a and 42b from the opposing outsides as shown in FIG. 8, for example, a method of using one resin member surrounding the contact member 41 to press and hold the contact member 41 from the periphery may be used. The material of the contact member 41 may be any material harder than the wedge 112, and may be, for example, various metal materials. The resin members 42a and 42b are placed on the bottom plate 6b of the housing 6 via vibration-proof rubbers 43a and 43b, respectively. Vibration-proof rubbers 43c and 43d are interposed between the top plate 6a of the housing 6 and the resin members 42a and 42b. The accelerometer 44 is composed of an L-shaped plate member 441 and a sensor 442 that measures the vibration of the wedge 112 transmitted to the plate member 441 via the contact member 41. The long portion 441a of the plate member 441 is attached to the upper surface of the contact member 41. The sensor 442 is attached to the short portion 441b of the plate member 441. Furthermore, the plate-like member 441 is not sandwiched or fixed between the resin members 42a and 42b or the anti-vibration rubbers 43a, 43b, 43c, and 43d, and is arranged so as to be able to vibrate. For this reason, for example, the anti-vibration rubbers 43c and 43d may be provided with a notch so as not to come into contact with the long portion 441a of the plate-like member 441. The second measuring device 4 attaches the accelerometer 44 to the contact member 41 in contact with the wedge 112, and measures the vibration of the wedge 112 when a strike from the striking portion 21a is applied to the wedge 112 via the contact pin 24.

[0027] FIG. 9 is a diagram showing the looseness measurement device 1 in a state where the electromagnet 52 is not activated. FIG. 10 is a diagram showing the looseness measurement device 1 in a state where the electromagnet 52 is activated. As shown in FIGS. 9 and 10, the suction device 5 is provided with a magnet wheel 51 for moving, and an electromagnet 52 capable of attracting the housing 6 to the inner peripheral surface 110a of the stator 110 during looseness measurement. The magnet wheel 51 is connected to the top plate portion 6a of the housing 6 via an elastic body 53 arranged in the housing 6, and is configured to be retractable into the housing 6 through a wheel opening (not shown) formed in the bottom plate portion 6b of the housing 6. As the elastic body 53 connecting the housing 6 and the magnet wheel 51, for example, a leaf spring or the like can be used. By connecting the housing 6 and the magnet wheel 51 via the elastic body 53, the housing 6 can be lifted from the inner peripheral surface 110a of the stator 110 by the elastic force of the elastic body 53, and the looseness measurement device 1 can be moved smoothly. In order to move the looseness measurement device 1 in the longitudinal direction of the AC motor 100 (stator 110), for example, a method of attaching a wire to the housing 6 and pulling the wire from outside the AC motor 100 can be adopted.

[0028] Moreover, by employing magnet wheels 51 as wheels for moving the looseness measurement device 1 in the longitudinal direction of the AC motor 100 (stator 110), the magnet wheels 51 are attracted to the inner peripheral surface 110a of the stator 110 (the inner peripheral surface 111a of the iron core 111) by magnetic force. This makes it possible to hold the looseness measurement device 1 on the inner peripheral surface 110a of the stator 110 regardless of the angle of the looseness measurement device 1 with respect to the inner peripheral surface 110a of the stator 110. Therefore, even if the looseness measurement device 1 is in a gap formed between the stator 110 and the rotor 120 such that the inner peripheral surface 110a of the stator 110 is above the outer peripheral surface 120a of the rotor 120, for example, it becomes possible to move the looseness measurement device 1 in the longitudinal direction of the AC motor 100 (stator 110) while holding it on the inner peripheral surface 110a of the stator 110.

[0029] In the looseness measurement device 1 according to the embodiment, after the looseness measurement device 1 is moved to a predetermined measurement position, the impact device 2 impacts the wedge 112, and the first measurement device 3 and the second measurement device 4 perform measurements. During the impact and measurement, the magnet wheel 51 is stored inside the housing 6, and the housing 6 is brought into close contact with the inner peripheral surface 110a of the stator 110 of the AC motor 100.

[0030] Here, the looseness measurement device 1 according to the embodiment is capable of tightly contacting the inner peripheral surface 110a of the stator 110 (the inner peripheral surface 111a of the iron core 111) with the housing 6 by the magnetic force of electromagnets 52 arranged on both sides of the housing 6 in the width direction perpendicular to the longitudinal direction. As shown in Fig. 9, the electromagnets 52 are not operated except when measuring the looseness (when striking and measuring), such as when moving the looseness measurement device 1, but are operated only when measuring the looseness (when striking and measuring), as shown in Fig. 10, to attract the inner peripheral surface 110a of the stator 110 by magnetic force.

[0031] As the electromagnet 52, for example, an electromagnet having both ends 521a, 521b of a U-shaped yoke 52a facing the inner circumferential surface 110a of the stator 110 and an exciting coil 52b in the center of the longitudinal direction of the yoke 52a as shown in Fig. 9 can be used. When such an electromagnet 52 is used, a current is passed through the exciting coil 52b in a state in which the looseness measuring device 1 is moved to a predetermined measurement position on the inner circumferential surface 110a of the stator 110. As a result, the ends 521a, 521b of the yoke 52a attract the inner circumferential surface 110a of the stator 110 via the housing 6, and as a result, the housing 6 is fixed in close contact with the inner circumferential surface 110a of the stator 110. Therefore, the state in which the looseness measurement device 1 adheres to the inner peripheral surface 110a of the stator 110 is stable, and as a result, stable measurement data can be obtained, and the looseness of the wedge 112 can be inspected with high accuracy.

[0032] In order to smoothly move the looseness measurement device 1 along the longitudinal direction of the stator 110 of the AC motor 100, a guide rail for placing the magnet wheel 51 and guiding the movement of the magnet wheel 51 may be provided on the inner peripheral surface 110a of the stator 110. By providing the guide rail in this manner, it is possible to smooth the portion with which the magnet wheel 51 comes into contact, and therefore it is possible to more smoothly perform the operation of moving the looseness measurement device 1 in the longitudinal direction of the stator 110. Also, the guide rail may have a structure in which the magnet wheel 51 is sufficiently attracted to the inner peripheral surface 110a of the stator 110 via the guide rail by magnetic force, and the contact pin 24 of the impact device 2 comes into direct contact with the wedge 112 without the guide rail.

[0033] Furthermore, even when a guide rail is prepared to move the looseness measurement device 1 in the longitudinal direction of the AC motor 100, the use of the magnet wheels 51 eliminates the need to have the guide rail bear the load of the looseness measurement device 1. This simplifies the structure of the guide rail and reduces its weight, which has the effect of improving workability. Furthermore, because the guide rail can be made lighter, it is possible to prevent the guide rail from bending under its own weight and to prevent the measurement position on the guide rail where the looseness measurement device 1 measures the looseness of the wedge 112 from shifting, so that the looseness of the wedge 112 can be inspected with high accuracy.

[0034] Here, the magnet wheel 51 is configured to allow the looseness measurement device 1 to move along the axial direction of the AC motor 100. Therefore, when inspecting the wedge 112 at another position in the circumferential direction of the AC motor 100, the looseness measurement device 1 is manually moved to the other position. Note that the magnet wheel 51 is not limited to one configured to allow the looseness measurement device 1 to move along the axial direction of the AC motor 100, and may be configured to allow the looseness measurement device 1 to move in the circumferential direction of the AC motor 100 as well.

[0035] The calculation device 8 calculates an acceleration ratio, which is the ratio of the acceleration of the wedge 112 to the acceleration of the impact given by the impact device 2 to the wedge 112, which is the object to be impacted. Specifically, the calculation device 8 calculates the acceleration ratio from data on the impact acceleration measured by the first measuring device 3 and data on the acceleration (response acceleration) of the wedge 112 measured by the second measuring device 4, which are received wired or wirelessly from the first measuring device 3 and the second measuring device 4. The acceleration ratio data obtained by the calculation of the calculation device 8 is transmitted to the determination device 9 wired or wirelessly.

[0036] The determination device 9 determines the degree of loosening of the wedge 112 based on the calculation result (acceleration ratio) received from the calculation device 8. If the wedge 112 is not loose, the vibration of the wedge 112 is small. On the other hand, if the wedge 112 is loose, the wedge 112 does not vibrate in accordance with the applied impact when struck, and the acceleration ratio becomes large. The relationship between the acceleration ratio and the loosening of the wedge 112 can be obtained in advance by performing a preliminary test. It is also possible to determine the degree of loosening of the wedge 112 without a preliminary test by accumulating measurement results for AC motors 100 having a similar shape and structure.

[0037] The control device 7 controls the operation of each of the devices, such as the impact device 2 (rotation device 23), the first measuring device 3, the second measuring device 4, and the suction device 5 (electromagnet 52), provided in the loosening measuring device 1, by transmitting control signals via wire or wirelessly.

[0038] The inspection method for an AC motor 100 using the inspection device 10 of the embodiment involves inserting the looseness measurement device 1 into the gap formed between the stator 110 and rotor 120 of the AC motor 100, striking a wedge 112 that secures a coil 113 arranged in a slot 114 of the stator 110, and determining the degree of looseness of the wedge 112 from the acceleration ratio, which is the ratio of the acceleration of the struck object, i.e., the wedge 112, to the acceleration of the struck impact.

[0039] Specifically, first, the cover of the AC motor 100 to be inspected is removed to expose the cross sections of the stator 110 and the rotor 120 as shown in FIG. 2, and then the looseness measuring device 1 is inserted into the gap formed between the inner peripheral surface 110a of the stator 110 and the outer peripheral surface 120a of the rotor 120. Then, the looseness measuring device 1 is moved in a direction parallel to the rotation axis of the AC motor 100, and stopped when it arrives at a predetermined measurement position. Next, the electromagnet 52 is controlled by the control device 7 to operate the electromagnet 52 of the looseness measuring device 1 at the predetermined measurement position, and the housing 6 is attracted and fixed to the inner peripheral surface 110a of the stator 110 (the inner peripheral surface 111a of the iron core 111) by magnetic force. In this state, the contact pin 24 is in contact with the wedge 112.

[0040] Next, the impact device 2 of the looseness measuring device 1 starts measuring the looseness of the wedge 112. Specifically, the control device 7 controls the rotation imparting device 23 to rotate the cam 22, lifting the cam contact portion 21b of the leaf spring 21 and elastically deforming the leaf spring 21, and then releasing it. The impact portion 21a of the leaf spring 21 thus released impacts the contact pin 24 that is in contact with the wedge 112 beforehand, thereby impacting the wedge 112 via the contact pin 24.

[0041] In addition, in conjunction with the impact by the impact device 2, the control device 7 controls the first measuring device 3, and the acceleration of the impact given to the wedge 112 is measured by the first measuring device 3. The measurement result of the impact acceleration measured by the first measuring device 3 is transmitted to the calculation device 8. The calculation device 8 applies a low-pass filter to the waveform of the impact acceleration, which is the data of the acceleration of the impact measured by the first measuring device 3, and then obtains a peak-held value A1. In addition, simultaneously with the measurement by the first measuring device 3, the control device 7 controls the second measuring device 4, and the acceleration (response acceleration) of the wedge 112 is measured by the second measuring device 4 from the vibration of the wedge 112. The measurement result of the acceleration (response acceleration) of the wedge 112 measured by the second measuring device 4 is transmitted to the calculation device 8. The calculation device 8 applies a low-pass filter to the waveform of the acceleration (response acceleration) of the wedge 112, which is the data of the acceleration (response acceleration) of the wedge 112 measured by the second measuring device 4, and then obtains a peak-held value A2. Then, the calculation device 8 obtains an acceleration ratio, which is the ratio of the acceleration of the wedge 112 (the response acceleration) to the acceleration of the impact given to the wedge 112 by the impact device 2, by dividing the value A2 by the value A1 (A2 / A1).

[0042] It is preferable that the impact and each acceleration measurement by the looseness measuring device 1 are performed multiple times for one measurement point, and the average value of each acceleration ratio obtained for each impact is used as a criterion for judging the degree of looseness of the wedge 112. Here, when calculating the average value of each acceleration ratio obtained by multiple impacts, it is preferable to calculate the average value of only each acceleration ratio for the remaining number of times, excluding each acceleration ratio obtained by the first few impacts among the multiple impacts. For example, it is preferable to calculate the average value of each acceleration ratio obtained by the third and subsequent impacts. This is for the following reason. Due to the variation in surface roughness of the inner peripheral surface 110a of the stator 110, the initial adhesion state of the housing 6 to the inner peripheral surface 110a of the stator 110 (the inner peripheral surface 111a of the iron core 111) may be unstable. However, a stable adhesion state is realized by about two impacts.

[0043] The data of the acceleration ratio (average value of acceleration ratio) calculated by the calculation device 8 is transmitted to the determination device 9. The determination device 9 determines the degree of loosening of the wedge 112 based on the acceleration ratio (average value of acceleration ratio) calculated as a result of the calculation device 8, from the relationship between the acceleration ratio (average value of acceleration ratio) and the degree of loosening of the wedge 112, which has been measured in advance or found based on past performance.

[0044] As a result, in the inspection device 10 according to the embodiment, the looseness of the wedge 112 can be accurately inspected without pulling out the rotor 120, which can lead to reduction in construction costs and construction time. Also, in the inspection device 10 according to the embodiment, the striking force of the striking portion 21a of the leaf spring 21 is applied to the wedge 112 via the contact pin 24 that has been brought into contact with the wedge 112 in advance, so that a stable striking force can be applied to the wedge 112, suppressing variation in the measurement results, and improving the accuracy of determining the degree of looseness of the wedge 112. [Explanation of symbols]

[0045] 1. Looseness measuring device 2. Percussion device 3. First Measuring Device 4. Second Measuring Device 5 Adsorption device 6. Chassis 6a Top plate 6b Bottom plate part 7 Control Device 8 Computing equipment 9 Judgment device 10 Inspection equipment 21 Leaf spring 21a Striking section 21b Cam contact part 22 Cam 23 Rotation device 24 Hitting Bishi 25 Fixed base 26 Elastic Body 41 Contact member 42a, 42b Resin member 43a, 43b, 43c, 43d Anti-vibration rubber 44 Accelerometer 51 Magnetic Wheel 52 Electromagnet 52a York 52b Excitation coil 53 Elastic Body 61 Opening 62 Opening 100 AC motor 110 Stator 110a Inner surface 111 Iron Core 112 Wedge 120 Rotor 120a Outer surface 441 Plate-shaped members 441a Long section 441b Short section 442 Sensors 521a,521b Tip

Claims

1. An impact device that impacts a wedge that fixes a stator of an AC motor; a first measuring device for measuring the acceleration of the impact applied by the impact device; a second measuring device for measuring the acceleration of the wedge; a housing that houses the impact device, the first measuring device, and the second measuring device; The loosening measuring device has the impact device includes a leaf spring, a cam that rotates to push up and elastically deform the leaf spring, a rotation imparting device that rotates the cam, and a contact pin that transmits the impact from the leaf spring to the wedge, The housing includes a magnet wheel that is connected to the housing via an elastic body and that can be stored inside the housing, and an electromagnet that can attract the housing to an inner peripheral surface of the stator. An inspection device for an AC motor.

2. a calculation device for calculating an acceleration ratio, which is a ratio of an acceleration of the wedge to an acceleration of a strike applied to the wedge by the striking device; a determination device that determines a degree of loosening of the wedge using a calculation result of the calculation device; 2. The inspection device for an AC motor according to claim 1, further comprising:

3. 3. A method for inspecting an AC motor, comprising: inserting the looseness measurement device of the inspection apparatus for an AC motor according to claim 1 or 2 into a gap formed between a rotor and a stator of the AC motor; applying an impact to the wedge using the looseness measurement device; and determining a degree of looseness of the wedge from a relationship between the acceleration of the impact and the acceleration of the wedge.

4. The method for determining the degree of loosening of the wedge comprises: a step of applying a low-pass filter to the waveform of the acceleration of the impact applied to the wedge and then determining a peak hold value A1; a step of applying a low-pass filter to the waveform of the wedge acceleration and then obtaining a peak-held value A2; A step of calculating the ratio of A2 / A1 for each impact to obtain an acceleration ratio; performing multiple hits on each measurement location and calculating an average value after eliminating data related to the initial hits; a step of determining a degree of loosening of the wedge from a previously prepared relationship between the acceleration ratio and the degree of loosening based on the average value of the acceleration ratio thus obtained; 4. The method for inspecting an AC motor according to claim 3, further comprising the steps of:

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