Fixation force evaluation method

Abstract

The present invention relates to a fixing force evaluation method, the method comprising: a natural vibration frequency measuring step, the natural vibration frequency measuring step is used to measure the natural vibration frequency of a stator in which a tooth portion and a stator coil are fixed by insulating paper; and a fixing force evaluation step, when the natural vibration frequency of the stator measured in the fixing vibration frequency measuring step is greater than or equal to a predetermined judgment vibration frequency, the fixing force evaluation step evaluates that the fixing force of the insulating paper is large compared to a case where the natural vibration frequency is lower than the judgment vibration frequency. Therefore, since the fixing force of the insulating paper is evaluated in the fixing force evaluation step based on the natural vibration frequency of the stator measured in the natural vibration frequency measuring step, the fixing force of the insulating paper can be evaluated by measuring the natural vibration frequency of the stator without destroying the stator.

Description

Technical Field

[0001] The present invention relates to a fixing force evaluation method for evaluating the fixing force of insulating paper that fixes teeth formed on a stator core and a coil wound on the teeth, and to a technology for evaluating the fixing force of the insulating paper without destroying the stator in which the teeth and the coil are fixed by the insulating paper. Background Art

[0002] A stator of a rotating electric machine is known, which is equipped with (a) a tooth portion formed on a stator core, (b) a coil wound on the tooth portion, and (c) an insulating paper having a foaming adhesive layer on both sides of a base material and interposed between the tooth portion and the coil, and (d) the tooth portion and the coil are fixed by the insulating paper by heating the foaming adhesive layer. For example, the stator of a rotating electric machine described in Japanese Patent Application Laid-Open No. 2018-107921 belongs to this. Summary of the invention

[0003] However, in the stator of a rotating electric machine such as Japanese Patent Laid-Open No. 2018-107921, when evaluating the fixing force of the insulating paper that fixes the teeth and the coils, for example, as an evaluation method, it is considered to cut the stator in a direction perpendicular to its center line, and use an instrument to push the coils of the stator exposed on the cut surface one by one until the coils are separated from the teeth one by one, thereby measuring the fixing force of the insulating paper. However, in such a method, there is a problem that the stator will be destroyed in order to evaluate the fixing force of the insulating paper.

[0004] The present invention has been made under the above circumstances, and an object of the present invention is to provide a fixing force evaluation method for evaluating the fixing force of insulating paper without destroying the stator.

[0005] The inventors of the present invention have repeatedly conducted various studies, and as a result, obtained the facts described below. That is, it was found that when the hardness of the foam adhesive layer that fixes the tooth portion and the coil, which serves as the fixing force of the insulating paper, changes, the rigidity of the stator as a whole changes, and the natural vibration frequency of the stator changes. In other words, it was found that when the natural vibration frequency of the stator is high, the fixing force of the insulating paper becomes larger than when the natural vibration frequency is low. And, it is assumed that by measuring the natural vibration frequency of the stator, the fixing force of the insulating paper can be inferred. The present invention is made based on such knowledge.

[0006] The main purpose of the first invention is, (a) a fixing force evaluation method for evaluating the fixing force of insulating paper, wherein the insulating paper has a foamed adhesive layer on both sides, and the insulating paper is sandwiched between a tooth portion formed on a stator core and a coil wound on the tooth portion to fix the tooth portion and the coil, and the fixing force evaluation method comprises: (b) a natural vibration frequency measuring step, wherein the natural vibration frequency measuring step is used to measure the natural vibration frequency of the stator in which the tooth portion and the coil are fixed by the insulating paper; and (c) a fixing force evaluation step, wherein when the natural vibration frequency of the stator measured in the natural vibration frequency measuring step is high, the fixing force evaluation step evaluates that the fixing force of the insulating paper is large compared with a case where the natural vibration frequency is low.

[0007] In addition, the gist of the second invention is that in the first invention, in the fixing force evaluation process, when the natural vibration frequency measured in the natural vibration frequency measurement process is greater than or equal to a predetermined judgment vibration frequency, it is estimated that the fixing force of the insulating paper satisfies a predetermined reference value.

[0008] In addition, the main point of the third invention is that in the first invention or the second invention, in the natural vibration frequency measuring process, a frequency analysis is performed on a signal detected by a sensor arranged at a predetermined second position of the stator by exciting a predetermined first position of the stator with a hammer, and the frequency at which the sound pressure level forms the highest peak is taken as the natural vibration frequency of the stator.

[0009] In addition, the gist of the fourth invention is that, in the invention described in any one of the first invention to the third invention, (a) the foaming adhesive layer is a layer that expands by being heated and then hardens, and (b) the harder the hardened foaming adhesive layer becomes, the higher the natural vibration frequency measured in the natural vibration frequency measuring step becomes.

[0010] According to the first invention, the fixing force evaluation method comprises: (b) a natural vibration frequency measuring step, the natural vibration frequency measuring step is used to measure the natural vibration frequency of the stator in which the teeth and the coil are fixed by the insulating paper; and (c) a fixing force evaluation step, when the natural vibration frequency of the stator measured in the natural vibration frequency measuring step is high, the fixing force evaluation step evaluates that the fixing force of the insulating paper is large compared with the case where the natural vibration frequency is low. Therefore, since the fixing force of the insulating paper is evaluated in the fixing force evaluation step based on the natural vibration frequency of the stator measured in the natural vibration frequency measuring step, the fixing force of the insulating paper can be evaluated by measuring the natural vibration frequency of the stator without destroying the stator.

[0011] According to the fixing force evaluation method of the second invention, in the fixing force evaluation step, when the natural vibration frequency measured in the natural vibration frequency measurement step is greater than or equal to a predetermined judgment vibration frequency, it is estimated that the fixing force of the insulating paper meets a predetermined reference value. Therefore, it is possible to estimate whether the fixing force of the insulating paper meets the reference value by measuring the natural vibration frequency of the stator without destroying the stator.

[0012] According to the fixing force evaluation method of the third invention, in the natural vibration frequency measuring step, the frequency analysis is performed on the signal detected by the sensor provided at the predetermined second position of the stator by exciting the predetermined first position of the stator with a hammer, and the frequency at which the sound pressure level forms the highest peak is taken as the natural vibration frequency of the stator. Therefore, the natural vibration frequency of the stator can be well measured in the natural vibration frequency measuring step.

[0013] According to the fixing force evaluation method of the fourth invention, (a) the foam adhesive layer is a layer that expands by being heated and then hardens, and (b) the harder the hardened foam adhesive layer becomes, the higher the natural vibration frequency measured in the natural vibration frequency measuring step becomes. Therefore, the hardness of the hardened foam adhesive layer can be evaluated by measuring the natural vibration frequency of the stator without destroying the stator. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, in which like reference numerals denote like components, and in which:

[0015] Figure 1 It is a perspective view for explaining a schematic structure of a stator of a rotating electrical machine for a vehicle to which the present invention is preferably applied.

[0016] Figure 2 This is a diagram in which insulating paper is arranged in a slit formed in a stator core and a coil segment is inserted into the slit, and is a diagram in which the outer peripheral side of the stator core is viewed from the inner peripheral side of the stator core.

[0017] Figure 3A This is to illustrate the structure of the insulating paper sandwiched between the teeth and the coil segment. Figure 2 The enlarged view of the part encircled by the dotted circle.

[0018] Figure 3B Yes means through Figure 3A The insulating paper shown in FIG. 1 is heated, and the foam adhesive layer is foamed and expanded.

[0019] Figure 4This is a process diagram for explaining the main part of a fixing force evaluation method for evaluating the fixing force of insulating paper that fixes teeth and stator coils in a stator.

[0020] Figure 5 Yes Description Figure 4 FIG. 1 is a diagram showing a process for measuring the natural frequency of a component.

[0021] Figure 6 This is a diagram showing an example of the analysis result displayed on the display unit of the FFT analyzer in the natural frequency measurement step.

[0022] Figure 7 This is a graph showing stators having different insulating paper fixing forces manufactured by varying the thickness of the foamed adhesive layer and the like, and showing the relationship between the insulating paper fixing force and the natural vibration frequency of the stator in these stators. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the accompanying drawings are appropriately simplified or deformed, and the dimensional ratios and shapes of the various parts are not necessarily drawn correctly.

[0024] Figure 1 It is a stereoscopic diagram illustrating the schematic structure of the stator 10 of the vehicle rotary electric machine MG suitable for adopting the present invention. In addition, the vehicle rotary electric machine MG is, for example, a so-called electric generator installed in a hybrid vehicle or an electric car, which has the function of an electric motor (motor) and the function of a generator (generator). In addition, the vehicle rotary electric machine MG is, for example, a driving source for driving a vehicle. In addition, the vehicle rotary electric machine MG is equipped with a cylindrical stator 10 centered on the rotation axis C of the rotor to be described later and a rotor not shown in the figure arranged on the inner circumference side of the stator 10. In addition, the rotor is rotated by a rotating magnetic field generated by the stator 10.

[0025] like Figure 1 As shown, the stator 10 is equipped with a stator core 12, a stator coil (coil) 14 and a power line 16. The stator core 12 is formed by stacking a plurality of electromagnetic steel sheets and extending in a cylindrical shape with the rotation axis C as the center. In addition, a plurality of teeth 12a are formed on the stator core 12, protruding from the inner circumference of the cylindrical stator core 12 toward the inner circumference. In addition, as shown in FIG. Figure 1 As shown, slits 12b, which are slot-shaped spaces, are formed between teeth 12a adjacent to each other in the circumferential direction of the stator core 12. In addition, the stator coil 14 is wound around the teeth 12a.

[0026] The stator coil 14 is a three-phase coil of, for example, U-phase, V-phase and W-phase, and each end of the stator coil 14 is electrically connected to a power line 16. At the end of each power line 16, an external terminal 18 for connecting to an inverter (not shown) is installed.

[0027] Figure 2 The insulating paper 20 is arranged in the slit 12b formed in the stator core 12, and the coil segment 22 is inserted into the slit 12b. Figure 2 This is a diagram showing the outer peripheral side of the stator core 12 as viewed from the inner peripheral side of the stator core 12. Figure 2 As shown, the coil segment 22 is bent into a substantially U-shape, and the coil segment 22 has a pair of arm portions 22a extending in a straight line, and a connecting portion 22b connecting the ends of the pair of arm portions 22a to each other. In addition, the coil segment 22 is a coil segment having an insulating film such as enamel formed on the surface of a flat wire with a rectangular cross-section such as a long strip conductor plate. In addition, the insulating film is removed from the terminal portions 22c of the pair of arm portions 22a. Figure 1 As shown in FIG. 1 , the end portions 22c of the pair of arm portions 22a of the coil segment 22 protruding from the slit 12b are bent so that the end portions 22c are separated from each other in the circumferential direction of the stator core 12, and are connected to the end portions 22c of the arm portions 22a of other coil segments 22 by welding, for example. Figure 1 As shown, the stator coil 14 wound around the teeth 12 a is formed by connecting a plurality of coil segments 22 .

[0028] like Figure 2 As shown, the insulating paper 20 is sandwiched between the tooth portion 12a and the coil segment 22 (ie, the stator coil 14) in order to insulate the tooth portion 12a and the coil segment 22, and is a sheet bent in accordance with the shape of the slit 12b. Figure 3A As shown, the insulating paper 20 is an insulating paper having a foam adhesive layer 26 on both sides 24a and 24b of a base material 24. The base material 24 is a material obtained by forming a heat-resistant and insulating resin material into a sheet. The resin material used for the base material 24 is, for example, polyethylene naphthalate (PEN). The foam adhesive layer 26 is a layer of a thermosetting resin that expands by heating and then hardens, and has adhesiveness itself. The foam adhesive layer 26, such as Figure 3B As shown, the foaming and expansion is caused by the predetermined heating, and the thickness t of the foaming adhesive layer 26 becomes thicker, for example. Figure 3A In addition, the foaming adhesive layer 26 is a layer of thermosetting resin in which resin beads (particles) containing a foaming agent are added to an epoxy-based thermosetting resin. When the foaming adhesive layer 26 is heated, the resin beads expand and the foaming adhesive layer 26 expands. In addition, Figure 3AThis is to illustrate the structure of the insulating paper 20 sandwiched between the tooth portion 12a and the coil segment 22, and Figure 2 The enlarged view of the part circled by the dotted line A in FIG. Figure 3B Yes means Figure 3A The insulating paper 20 shown is heated to cause the foam adhesive layer 26 to foam and expand.

[0029] In the stator 10 constructed as described above, when the foamed adhesive layer 26 of the insulating paper 20 is heated, Figure 3B As shown, the foam adhesive layer 26 expands and then hardens, and the teeth 12 a of the stator core 12 and the stator coil 14 are fixed by the insulating paper 20 .

[0030] Next, a fixing force evaluation method for evaluating the fixing force FS [N] of the insulating paper 20 fixing the tooth portion 12a and the stator coil 14 will be described in detail. The fixing force evaluation method is as follows: Figure 4 As shown, there are a natural frequency measuring step P1 and a fixing force evaluation step P2. In addition, the fixing force evaluation method is used, for example, when a predetermined stator 10 is extracted from a plurality of manufactured stators 10 as a sample and the fixing force FS of the insulating paper 20 of the sample is inspected. In addition, Figure 4 This is a process diagram for explaining a main part of a fixing force evaluation method for evaluating the fixing force FS of the insulating paper 20 .

[0031] The natural frequency measuring step P1 is to measure the natural frequency of the stator 10 in which the teeth 12a of the stator core 12 and the stator coil 14 are fixed by the insulating paper 20. Figure 5 The process of determining the natural vibration frequency NF [Hz] of the stator 10 shown in FIG. Figure 5 In the illustrated stator 10 , the coil ends of the stator coil 14 protruding from the slits 12 b , that is, the terminal ends 22 c of the plurality of coil segments 22 protruding from the slits 12 b are integrally covered with the resin 28 .

[0032] In the natural frequency determination step P1, as Figure 5 As shown, the FFT analyzer 34 performs frequency analysis on the signal detected by the acceleration sensor (sensor) 32 provided at the predetermined second part PL2 of the stator 10 by exciting the predetermined first part PL1 of the stator 10 with the hammer 30, and based on the analysis result displayed on the display unit of the FFT analyzer 34, the frequency F [Hz] at which the sound pressure level SL [dB] forms the highest peak is taken as the natural vibration frequency NF [Hz] of the stator 10. In addition, in the natural vibration frequency measurement step P1, for example, the first part PL1 is directly struck with a hammer 30 such as an iron hammer or a wooden hammer to excite the first part PL1. In addition, Figure 6FIG. 4 is a diagram showing an example of the analysis result displayed on the display unit of the FFT analyzer 34. Figure 6 As shown in FIG. 1 , the signal detected by the acceleration sensor 32 is subjected to frequency analysis by the FFT analyzer 34 and is represented by a two-dimensional coordinate system consisting of a vertical axis representing the sound pressure level SL [dB] and a horizontal axis representing the frequency F [Hz]. Figure 6 In the analysis result shown, the point PK is the peak value of the highest sound pressure level SL. In the natural frequency measuring step P1, the frequency F of the point PK is used as the fixed vibration frequency NF of the stator 10. In addition, the FFT analyzer 34 is a measuring device that performs frequency analysis on the signal detected by the acceleration sensor 32 by fast Fourier transform and displays the analysis result on the display unit. In this embodiment, for example, an FFT analyzer manufactured by Onosokki is used for the FFT analyzer 34. In addition, in the natural frequency measuring step P1, for example, the stator 10 is excited by a hammer 30 in a state where the lower part of the fastening bolts (not shown) inserted through the three insertion holes 12c, 12d, and 12e formed in the stator core 12 is constrained on the table via springs (not shown). For example, the spring is a spring with a spring constant of about 2N / mm.

[0033] In addition, in the present embodiment, in the natural frequency measuring step P1, Figure 5 As shown, the first part PL1 is set at the predetermined first excitation part KP1 of the stator 10, and the second part PL2 is set at the predetermined first response part OP1 of the stator 10. In addition, the first excitation part KP1 and the first response part OP1, as shown in FIG. Figure 5 As shown, they are respectively the peripheral parts of the insertion through hole 12c at the end surface 12f on the resin 28 side of the stator core 12. In addition, in the natural frequency measurement step P1, the optimal parts of the first part PL1 and the second part PL2 are investigated so that the measurer can correctly measure the natural frequency NF from the analysis result displayed on the display part of the FFT analyzer 34, that is, so that the point PK displayed on the display part, that is, the peak value, is high and clearly output. That is, as Figure 5As shown, the first part PL1 is changed from the first excitation part KP1 to the fourth excitation part KP4, and the second part PL2 is changed from the first response part OP1 to the fourth response part OP4, and a total of 16 natural vibration frequency measurement steps P1 are actually performed, and a total of 16 CAE (Computer Aided Engineering) analyses are performed. According to the actual measurement results of the natural vibration frequency measurement step P1 and the analysis results obtained by the CAE analysis, when the first part PL1 is the first excitation part KP1 and the second part PL2 is the first response part OP1, the point PK, that is, the peak value is the highest and is output most clearly. In addition, as Figure 5 As shown, the second excitation part KP2 is the inner peripheral surface of the stator core 12 at the middle part between the insertion through hole 12d and the insertion through hole 12e. In addition, the third excitation part KP3 is the outer peripheral surface of the stator core 12 at the middle part between the insertion through hole 12d and the insertion through hole 12e. In addition, the fourth excitation part KP4 is the inner peripheral surface of the stator core 12 formed with the ear part 12g. In addition, the ear part 12g is a part of the outer periphery of the cylindrical stator core 12 that protrudes outward, and the insertion through hole 12c is formed in the ear part 12g. In addition, the second response part OP2 is the end face 12f of the stator core 12 at the middle part between the insertion through hole 12d and the insertion through hole 12e. In addition, the third response part OP3 is the outer peripheral surface of the stator core 12 at the middle part between the insertion through hole 12d and the insertion through hole 12e. In addition, the fourth response part OP4 is the boundary between the cylindrical stator core 12 and the ear 12g. In addition, the second excitation part KP2, the third excitation part KP3, the fourth excitation part KP4, the third response part OP3, and the fourth response part OP4 are respectively arranged at the middle position of the stator core 12 in the direction of the rotation axis C.

[0034] The fixing force evaluation step P2 is a step in which, when the natural vibration frequency NF of the stator 10 measured in the natural vibration frequency measurement step P1 is greater than or equal to the predetermined judgment vibration frequency NFJ [Hz], the fixing force FS of the insulating paper 20 is evaluated to be greater than the case where the natural vibration frequency NF is lower than the judgment vibration frequency NFJ. That is, the fixing force evaluation step P2 is a step in which, when the natural vibration frequency NF measured in the natural vibration frequency measurement step P1 is greater than or equal to the judgment vibration frequency NFJ, it is estimated that the fixing force FS of the insulating paper 20 satisfies the predetermined reference value FST [N]. In addition, the reference value FST is, for example, the minimum fixing force FS required for the insulating paper 20 predetermined when designing the stator 10, and the fixing force FS of the insulating paper 20 satisfies the reference value FST means that the fixing force FS of the insulating paper 20 is greater than or equal to the reference value FST. In addition, the judgment vibration frequency NFJ is determined in advance by experiments, etc. Figure 7 The natural frequency NF is determined in advance so that the reference value FST is fully satisfied. Figure 7 2 is a diagram showing the relationship between the fixing force FS of the insulating paper 20 and the natural frequency NF of the stator 10. Figure 7 In the present embodiment, for example, by using the insulating paper 20 with the thickness t of the foam adhesive layer 26 before being heated or the material of the foam adhesive layer 26 being changed, a plurality of (four in this embodiment) stators 10 with different fixing forces FS of the insulating paper 20 are manufactured, and the natural vibration frequency NF of the stator 10 and the fixing force FS of the insulating paper 20 are measured respectively. In addition, the vibration frequency NFJ is determined, for example, as Figure 7 As shown, the natural vibration frequency (NF1×SF) is obtained by multiplying the natural vibration frequency NF1 of the first measurement point MA1 having the lowest fixing force FS among the four first measurement points MA1 to the fourth measurement point MA4 by the safety factor SF predetermined to fully satisfy the reference value FST. Figure 7 The fixing force FS of the insulating paper 20 at the first measurement point MA1 to the fourth measurement point MA4 shown is measured by cutting the stator 10 in a direction perpendicular to the rotation axis C and pushing the stator coil 14 exposed on the cut surface, that is, the coil segments 22 one by one, with an instrument until the coil segments 22 are separated from the teeth 12a of the stator core 12 one by one. Figure 7 The natural vibration frequencies NF of the stator 10 at the first measurement point MA1 to the fourth measurement point MA4 shown are measured by the same method as the natural vibration frequency measurement step P1 described above. In addition, for the natural vibration frequencies NF of the first measurement point MA1 to the fourth measurement point MA4, the first part PL1 is the first excitation part KP1, and the second part PL2 is the first response part OP1. In addition, Figure 7 The solid line L shown is a line showing the tendency of the fixing force FS and the fixing vibration frequency NF at the first measurement point MA1 to the fourth measurement point MA4. Figure 7 In the embodiment, when the fixing force FS of the insulating paper 20 changes, the fixed vibration frequency NF of the stator 10 also changes, such as Figure 7 As shown by the solid line, there is a tendency that the greater the fixing force FS of the insulating paper 20 becomes, the higher the natural vibration frequency NF of the stator 10 becomes. In addition, since the fixing force FS of the insulating paper 20 is related to the hardness of the hardened foam adhesive layer 26, the harder the hardened foam adhesive layer 26 becomes, the greater the fixing force FS of the insulating paper 20 becomes. Therefore, the harder the hardness of the hardened foam adhesive layer 26 becomes, the higher the natural vibration frequency NF of the stator 10 measured in the natural vibration frequency measurement step P1 becomes.

[0035] As described above, the fixing force evaluation method according to the present embodiment includes: a natural vibration frequency measuring step P1 for measuring the natural vibration frequency NF of the stator 10 in which the teeth 12a and the stator coil 14 are fixed by the insulating paper 20; and a fixing force evaluation step P2 for evaluating that the fixing force FS of the insulating paper 20 is large when the natural vibration frequency NF of the stator 10 measured in the natural vibration frequency measuring step P1 is greater than or equal to the predetermined determination frequency NFJ, compared with the case where the natural vibration frequency NF is lower than the determination frequency NFJ. Therefore, since the fixing force FS of the insulating paper 20 is evaluated in the fixing force evaluation step P2 based on the natural vibration frequency NF of the stator 10 measured in the natural vibration frequency measuring step P1, the fixing force FS of the insulating paper 20 can be evaluated by measuring the natural vibration frequency NF of the stator 10 without destroying the stator 10.

[0036] In addition, according to the fixing force evaluation method of the present embodiment, in the fixing force evaluation step P2, when the natural vibration frequency NF measured in the natural vibration frequency measurement step P1 is greater than or equal to the predetermined judgment vibration frequency NFJ, it is estimated that the fixing force FS of the insulating paper 20 satisfies the predetermined reference value FST. Therefore, it is possible to estimate whether the fixing force FS of the insulating paper 20 satisfies the reference value FST by measuring the natural vibration frequency NF of the stator 10 without destroying the stator 10.

[0037] Furthermore, according to the fixing force evaluation method of the present embodiment, in the natural frequency measuring step P1, the frequency analysis is performed on the signal detected by the acceleration sensor 32 provided at the predetermined second part PL2 of the stator 10 by exciting the predetermined first part PL1 of the stator 10 with the hammer 30, and the frequency F at which the sound pressure level SL forms the highest peak is taken as the natural frequency NF of the stator 10. Therefore, in the natural frequency measuring step P1, the natural frequency NF of the stator 10 can be measured well.

[0038] In addition, according to the fixing force evaluation method of the present embodiment, the foam adhesive layer 26 is a layer that expands by being heated and then hardens, and the harder the hardened foam adhesive layer 26 becomes, the higher the natural vibration frequency NF measured in the natural vibration frequency measurement step P1 becomes. Therefore, the hardness of the hardened foam adhesive layer 26 can be evaluated by measuring the natural vibration frequency NF of the stator 10 without destroying the stator 10.

[0039] As mentioned above, although the embodiment of the present invention is described in detail based on the drawings, the present invention can also be applied to other aspects.

[0040] For example, in the first embodiment described above, the stator core 12 is formed by laminating a plurality of electromagnetic steel sheets, but the stator core 12 is not necessarily formed by a plurality of electromagnetic steel sheets. For example, the stator core 12 may be formed by forming magnetic powder, solid, etc.

[0041] In the first embodiment described above, the vehicle rotating electrical machine MG is an electric generator as a driving source for driving the vehicle, but the present invention is not limited to this embodiment. For example, the vehicle rotating electrical machine MG may be an electric motor for driving the vehicle without having a generator function but only having a motor function. In addition, the vehicle rotating electrical machine MG may be a regeneration generator without having a motor function but only having a generator function.

[0042] In the first embodiment described above, the foaming adhesive layer 26 of the insulating paper 20 is a layer of a thermosetting resin in which resin beads containing a foaming agent are added to an epoxy-based thermosetting resin, but the foaming adhesive layer 26 may be, for example, a layer of a thermosetting resin in which the resin beads are added to a thermosetting resin other than an epoxy-based thermosetting resin. In addition, polyethylene naphthalate (PEN) is used as the resin material of the base material 24 of the insulating paper 20, but, for example, a resin material such as polyphenylene sulfide (PPS) or epoxy resin may also be used.

[0043] In the natural frequency measuring step P1 of the first embodiment described above, the natural frequency NF of the stator 10 is measured by frequency analysis of the signal detected by the acceleration sensor 32 when the stator 10 is excited by the hammer 30 using the FFT analyzer 34. For example, instead of the hammer 30, a jig may be attached to the first part PL1 of the stator 10, and a weight at the end of the vibrator may hit the jig, thereby exciting the first part PL1.

[0044] In addition, the above is ultimately an implementation mode, and based on the knowledge of those skilled in the art, the present invention can be implemented in a manner that adds various changes and improvements.

Claims

1. A fixing force evaluation method for evaluating the fixing force of insulating paper, wherein the insulating paper has a foaming adhesive layer on both sides, the insulating paper is sandwiched between a tooth portion formed on a stator core of a stator and a coil wound on the tooth portion, the stator core includes a through hole formed on an end surface of the stator core, and the insulating paper fixes the tooth portion and the coil, characterized in that: The fixing force evaluation method comprises: Inserting a fastening bolt into the through hole of the stator core so that a portion directly below the fastening bolt is constrained by a table via a spring; In a state where the stator core is restrained by the table, measuring the natural vibration frequency of the stator in which the teeth and the coil are fixed by the insulating paper; When determining the natural vibration frequency, frequency analysis is performed on a signal detected by an acceleration sensor by means of a fast Fourier transform, wherein the acceleration sensor is disposed at a predetermined second position of the stator; When the measured natural vibration frequency of the stator is high, it is evaluated that the fixing force of the insulating paper is large compared to when the measured natural vibration frequency is low; Performing frequency analysis on a signal detected by the acceleration sensor disposed at a predetermined second portion of the stator by exciting a predetermined first portion of the stator with a hammer, and taking the frequency at which the sound pressure level forms the highest peak as the natural vibration frequency of the stator; and The predetermined first portion of the stator and the predetermined second portion of the stator are respectively located at peripheral portions of the through hole at an end surface of the stator core that is integrally covered with resin.

2. The fixing force evaluation method according to claim 1, characterized in that: When the measured natural vibration frequency is greater than or equal to a predetermined determination vibration frequency, it is estimated that the fixing force of the insulating paper satisfies a predetermined reference value.

3. The fixing force evaluation method according to claim 1 or 2, characterized in that: The foamed adhesive layer is a layer that expands by being heated and then hardens, The harder the hardness of the cured foamed adhesive layer becomes, the higher the natural frequency measured in the natural frequency measuring step becomes.

Images