WO2011102542A1

WO2011102542A1 - Method for determining fastening force of stacked core and method for manufacturing stacked core

Info

Publication number: WO2011102542A1
Application number: PCT/JP2011/054202
Authority: WO
Inventors: 匡平石田; 慶晃西名; 成治榎枝
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2010-02-22
Filing date: 2011-02-18
Publication date: 2011-08-25
Also published as: JP2012093333A; JP4840535B1

Abstract

A stacked core is formed from an electrical steel sheet. The stacked core is vibrated by means of a mechanical excitation force in the range from 1 N to 1,000 N depending on different fastening forces, the vibration level of at least one point of the stacked core is measured, and the relationship between the vibration level and the fastening force is obtained on the basis of the result of the measurement of the vibration level. It is therefore possible to accurately determine a fastening force that reduces noise by generating appropriate sliding friction between the stacked layers of the stacked core after the stacked core is excited.

Description

Method for determining fastening force of laminated iron core and method for producing laminated iron core

The present invention relates to a method for determining a clamping pressure of a laminated core in which electromagnetic steel sheets are laminated, and a method for manufacturing a laminated core by the method.

Among electrical steel sheets, grain oriented silicon steel sheets containing Si and having a crystal orientation in the (110) [001] direction have excellent soft magnetic properties, so that they are in the commercial frequency range. Widely used as various core materials.

However, such an electromagnetic steel sheet has magnetostriction accompanying excitation, and when an iron core (laminated iron core) manufactured by stacking electromagnetic steel sheets is excited, vibration (out-of-plane bending vibration: bending) occurs due to magnetostriction of the electromagnetic steel sheet. (vibration perpendicular to the plane) is generated and becomes a noise source. Therefore, when a transformer (transformer) is manufactured using a laminated core, an electromagnetic steel sheet having a small magnetostriction is generally used as the core material in order to suppress the generation of noise. However, there are cases where the noise level of the transformer cannot meet the required specifications, even though electrical steel sheets with low magnetostriction are used.

Many of the causes are resonance phenomena of natural vibration of the laminated core of the transformer and magnetostrictive vibration of the electrical steel sheet. That is, when the excitation power of the laminate core is an external force, forced vibration occurs, and when the excitation frequency matches the natural frequency of the laminate core, resonance occurs and a large amplitude occurs. For this reason, methods for designing transformers by focusing on the natural frequency of the laminated core have been studied.

If the natural vibration of the laminated core resonates with the magnetostrictive vibration of the electrical steel sheet, the rigidity (spring constant) of the laminated core is changed so that the natural frequency of the laminated core changes to avoid the resonance. ) Will be changed. For example, the fixing condition of the laminated core is adjusted or changed, or the number of laminated electromagnetic steel sheets is changed.

For example, Patent Document 1 discloses a method for measuring the natural frequency of the laminated core. This is to know the natural frequency of the laminated core by changing the excitation frequency stepwise and measuring the noise generated by the laminated core.

JP 2008-82778 A

However, a laminated iron core in which electromagnetic steel sheets are laminated is a complex structure and has an infinite number of natural frequencies in a frequency band of 50 Hz to 20 kHz that can be a target of noise. Generally, it is difficult to change only a specific natural frequency of a structure having a plurality of natural frequencies, and when the rigidity is changed, the whole natural frequency is shifted. For this reason, in the method of changing the rigidity of the laminated core, even if the resonance between the natural vibration of one natural frequency component and the magnetostrictive vibration is avoided, the natural vibration of another natural frequency component is newly resonated with the magnetostrictive vibration. Very likely to do. In the first place, since there are required specifications other than the natural vibration of the laminated core in the actual transformer design, it is not easy to change the rigidity of the laminated core.

As a simple model, FIG. 8 shows a frequency response characteristic (vertical axis: gain, horizontal axis: frequency) in the case of a single-degree-of-freedom vibration system, and a one-mass system model (single-degree-of-freedom vibration system). The relationship with each parameter in degree-of-freedom system model) is schematically shown. In general, in order to avoid resonance, the rigidity UP (increase the spring constant k) as shown in FIG. 8A or the rigidity DOWN (increase the spring constant k) as shown in FIG. 8B. The following measures are taken. However, as described above, in the case of a laminated iron core, a method of avoiding resonance at the operating frequency by changing the rigidity is actually difficult.

Therefore, as a countermeasure against vibration in the laminated iron core, the inventor considered a measure of damping UP (increasing the damping coefficient c) as shown in FIG. In this method, the natural frequency does not change, but the vibration amplitude can be reduced.
Furthermore, the inventor has found that the vibration amplitude can be remarkably reduced by increasing the damping coefficient by utilizing sliding friction between the laminations (between the electromagnetic steel sheets constituting the laminated core).

The detailed mechanism is shown in FIG. Here, each graph on the left side of FIG. 9 shows an external force (magnetostriction) pattern (vertical axis: magnetostriction, horizontal axis: time) applied to a transformer composed of a laminated core, and each central graph shows a fastening force (described later). ) Shows the frequency response function (frequency response function) of the transformer (vertical axis: response amplitude (gain), horizontal axis: frequency). Further, each graph on the right side of FIG. 9 shows a pattern of transformer vibration (out-of-plane bending vibration) when the external force is applied to the transformer having the frequency response function (vertical axis: amplitude of iron core vibration, horizontal axis: time. ).

In the case of a laminated iron core, the shape cannot be fixed simply by laminating electromagnetic steel sheets, so it is fixed by fastening means (clamping with steel, etc.). A compression force acts in the stacking direction when fixing by the fastening means, which is called a fastening force.

As shown in FIG. 9 (a), when the fastening force is weak, the friction between the laminations is small, so that the magnetic steel sheets move in a direction in which they are displaced from each other by the action of external force, and the rigidity of the laminated body as a whole decreases. However, in this case, only the natural frequency shifts, and the vibration amplitude itself does not change greatly. In addition, since a plurality of natural frequencies are shifted, another resonance that has not been a problem may occur due to low rigidity.

On the contrary, as shown in FIG. 9C, when the fastening force is too large, the friction between the layers increases, and the laminate behaves like a solid rigid body, so that the rigidity as the laminate increases. . However, in this case as well, the natural frequency only shifts, and the vibration amplitude itself does not change significantly. As in the case of low rigidity, another resonance that has not been a problem may occur.

On the other hand, when an appropriate fastening force is selected as shown in FIG. 9B, moderate sliding friction occurs between the layers. Since sliding friction has a damping action, the damping element of the laminated structure is reinforced, and even if the natural frequency does not change, its vibration amplitude is greatly reduced.

By determining the fastening force that generates appropriate sliding friction between the laminates by the mechanism as described above, it is possible to manufacture a laminated core with low vibration. And, it becomes possible to manufacture a low noise transformer by using the low vibration laminated core. However, it is difficult to accurately determine an appropriate fastening force in an actual machine or a conventional experimental facility.

The present invention has been made in view of the circumstances as described above, and in a laminated core in which electromagnetic steel sheets are laminated, in order to reduce vibration by using a damping effect due to sliding friction between the laminations, It is an object of the present invention to provide a method for determining a fastening force of a laminated core that can accurately determine a fastening force that generates an appropriate sliding friction, and a method for manufacturing a laminated core using the same.

In order to solve the above problems, the present invention has the following features.

(1) A laminated iron core is constructed using electromagnetic steel sheets, and is subjected to mechanical excitation force within a range of 1N to 1000N under different fastening forces, and one location of the laminated iron core. By measuring the above vibration level and determining the relationship between the vibration level and the fastening force based on the measurement result of the vibration level, the fastening force that reduces noise after exciting the laminated core is determined. A method for determining the fastening force of the laminated iron core.
The vibration level is an index representing the magnitude of vibration, and is obtained by measuring at least any one of displacement, speed, and acceleration (including calculation processing based on the measurement result). The measurement method is exemplified below, but is not limited thereto, and a known vibration analysis method can be applied.

(2) As the vibration level, an amplitude RMS (root-mean-square) value or maximum amplitude value of a time-series waveform (time history) of the measurement location is calculated, respectively, and the representative value of the amplitude RMS value or maximum amplitude value ( (representative value) or an average value is used. The method for determining a fastening force of a laminated core according to (1) above.

(3) The vibration level is obtained by frequency-analyzing a time-series waveform at a measurement location, calculating a sum of frequency components N times the excitation frequency, and using a representative point value or average value. The method for determining the fastening force of the laminated core according to (1).

(4) As the vibration level, frequency analysis is performed on the time-series waveform at the measurement location, the sum of the frequency components N times the excitation frequency is calculated, and the value or average value of the representative point is set as Wout. Analyzing the vibration frequency, calculating the sum of frequency components N times the excitation frequency, and using Wout / Fin, which is the ratio, as Fin, the laminated core according to (1) above Fastening force determination method.

(5) A fastening force is determined using the method for determining a fastening force of a laminate core according to any one of (1) to (4), and the laminate core is manufactured by fastening with the determined fastening force. A method for producing a laminated core, characterized by comprising:

In the present invention, for a laminated core in which electromagnetic steel sheets are laminated, a fastening force that generates appropriate sliding friction between the laminations is obtained in order to achieve low vibration by using a damping effect caused by sliding friction between the laminations. Can be determined. This makes it possible to produce a laminated core with low vibration. And, it becomes possible to manufacture a low noise transformer by using the low vibration laminated core.

In addition, the sliding friction phenomenon between laminates in a laminated core can be confirmed with a partial model or a small model, so it is possible to reduce the cost without producing a large-scale model on a full scale. With this, it is possible to determine an appropriate fastening force.

Conventionally, as shown in FIG. 10A, after manufacturing a laminated core and a transformer, when the vibration and noise are large, the fastening force is adjusted by trial and error. On the other hand, in this invention, as shown in FIG.10 (b), the suitable fastening force according to a use condition is calculated | required beforehand, and a laminated body core and a transformer can be manufactured with the appropriate fastening force. As a result, vibration and noise are reduced, and adjustment of the fastening force is unnecessary.
Further, although it has been difficult to obtain the correlation between the fastening force and the vibration by the conventional method, in the present invention, a detailed and accurate correlation can be easily obtained. For this reason, in this invention, the presence or absence of the noise improvement room from the present fastening force and the potential improvement range can be grasped easily, and it can contribute to the design of the transformer.

FIG. 1 is a diagram showing Embodiment 1 of the present invention. FIG. 2 is a diagram showing Embodiment 2 of the present invention. FIG. 3 is a diagram showing Embodiment 3 of the present invention. FIG. 4 is a view showing a laminated core in Examples 1 to 3 of the present invention. FIG. 5 is a diagram illustrating the evaluation / determination of the fastening force according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating the evaluation / determination of the fastening force according to the second embodiment of the present invention. FIG. 7 is a diagram illustrating the evaluation / determination of the fastening force according to the third embodiment of the present invention. 7A shows the result of evaluating the vibration level by acceleration, FIG. 7B shows the result of evaluating the vibration level by speed, and FIG. 7C shows the result of evaluating the vibration level by displacement. Indicates. FIG. 8 is a diagram showing the influence of stiffness and damping coefficient on frequency response characteristics in a one-degree-of-freedom vibration system in order to explain the basic concept of the present invention. FIG. 9 is a diagram showing the basic mechanism of the present invention. FIG. 10 is a diagram showing the difference in the fastening force determination procedure with the conventional method in order to explain the basic concept of the present invention.

In the present invention, in a laminated core in which electromagnetic steel sheets are laminated, an appropriate fastening force that generates appropriate sliding friction between the laminations is used in order to reduce vibration by using a damping effect caused by sliding friction between the laminations. I try to decide.

And the laminated iron core is manufactured by fastening the laminated electrical steel sheets with the fastening force determined in this way.

Embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
As shown in FIG. 1, a laminated iron core (preferably a small model or a partial model) 11 capable of adjusting a fastening force by a spring 13 through a bakelite 12 is prepared. Then, the waveform generated by the signal generator 21 is vibrated with a predetermined mechanical vibration force by the vibration exciter 22. Here, the predetermined mechanical excitation force is determined by vibration conditions or the like that may cause a problem in the actual use of the laminate core 11 to be measured, and is generally in the range of 1N to 1000N. Selected. The excitation force is measured by a load cell 23.
The displacement, speed, or acceleration is measured by the vibration sensor 24 (when no vibration is applied, the time is zero), and a time series waveform is obtained. Analyzing the obtained time-series waveform, and obtaining the RMS value (root mean square) or the maximum value in amplitude as the representative value or average value of vibration (multiple measurement points or arithmetic average value of multiple measurements) (This is the vibration level.)

Then, if the fastening force is changed and the representative value of vibration (RMS value or maximum amplitude) is sequentially measured, the relationship between the vibration level and the fastening force becomes clear. The same applies to the average value of vibration. Thus, an appropriate fastening force is determined according to the use situation of the laminated core.

[Embodiment 2]
As shown in FIG. 2, using a laminated iron core (small model or partial model) 11 whose fastening force can be adjusted by a spring 13 through a bakelite 12, a vibrator 22 with a sine wave fHz generated by a signal generator 21. To excite with a predetermined mechanical excitation force. Here, the predetermined mechanical excitation force is determined by vibration conditions or the like that may cause a problem in the actual use of the laminate core (small model or partial model) 11 to be measured. Is a mechanical excitation force selected from the range of 1N to 1000N. The excitation force is measured by the load cell 23.

Then, the displacement, velocity, or acceleration is measured by the vibration sensor 24 to obtain a time series waveform (when no vibration is applied, the zero point is set). The obtained time-series waveform is frequency-analyzed by the frequency analyzer 25, and the sum Wout of N-times components (N = 1, 2, 3,...) Of fHz among frequency components is obtained as a representative value of vibration (this) Is the vibration level). In addition, what is necessary is just to take an average, when calculating several points or measuring several times.

Then, by changing the fastening force and sequentially measuring the representative value (Wout) of the vibration, the relationship between the vibration level and the fastening force becomes clear. Thus, an appropriate fastening force is determined according to the use situation of the laminated core.
Compared with the method according to the first embodiment, the method according to the second embodiment can eliminate variations in amplitude levels that occur depending on the excitation force selected.

[Embodiment 3]
As shown in FIG. 3, using a laminated iron core (small model or partial model) 11 whose fastening force can be adjusted by a spring 13 via a bakelite 12, a vibrator 22 with a sine wave fHz generated by a signal generator 21. As in the second embodiment, vibration is performed with a predetermined mechanical vibration force.

Then, the displacement, velocity, or acceleration is measured by the vibration sensor 24 to obtain a time series waveform (when no vibration is applied, the zero point is set). The obtained time-series waveform is frequency-analyzed by the frequency analyzer 25 to obtain the total sum Wout of N-fold components (N = 1, 2, 3,...) Of fHz among the frequency components. In addition, what is necessary is just to take an average, when calculating several points or measuring several times. At the same time as calculating Wout, the excitation force is measured by the load cell 23 to obtain a time series waveform of the excitation force. The obtained time-series waveform is frequency-analyzed by the frequency analyzer 26 to obtain the sum Fin of N-fold components (N = 1, 2, 3,...) Of fHz out of the frequency components. And let Wout / Fin be the representative value of vibration (vibration level).

Then, if the fastening force is changed and the representative value (Wout / Fin) of vibration is sequentially measured, the relationship between the vibration level and the fastening force becomes clear. Thus, an appropriate fastening force is determined according to the use situation of the laminated core.
The method according to the third embodiment has the same advantages as the method according to the second embodiment, and further, compared to the method according to the second embodiment, the influence on the vibration level due to fluctuations (fluctuations and changes with time) of the excitation force of the vibrator 22. Can be offset.

[Example 1]

Example 1 of the present invention will be described. In Example 1, an appropriate fastening force was obtained according to Embodiment 1 of the present invention described above.

FIG. 4 shows a small laminated core 11 used in the first embodiment. As shown in the figure, this laminated core has a total of five pieces, each of which constitutes four sides and a piece which constitutes the central portion, butted and laminated in a step lap joint method. Is. Here, L1 = 500 mm, L2 = 500 mm, L3 = 100 mm, L4 = 100 mm, and 70 electromagnetic steel sheets having a thickness of 0.2 mm are laminated. As the electrical steel sheet, a general grain-oriented electrical steel sheet is used. The Si content is 2.0 to 4.5% by mass.
The excitation position was the midpoint of the side on the L1 side, and the measurement position of the vibration level was selected at three points at equal intervals on each side and the central piece, for a total of 15 points.

FIG. 5 is a graph of the vibration average value when the fastening force is changed. The vibration average value was the average value of 15 RMS of the acceleration measured by the vibration sensor with an excitation force of 30N (frequency sine wave of 100 Hz).

As shown in FIG. 5, since when the fastening force is 6N / cm ² is low vibration, proper fastening force was determined to 6N / cm ^2.

In addition, the maximum value of vibration is calculated | required instead of RMS value as an average vibration value at the time of changing fastening force, and it can also employ | adopt the fastening force with which the value becomes the smallest.
[Example 2]

Example 2 of the present invention will be described. In Example 2, an appropriate fastening force was obtained according to the second embodiment.

Also in this Example 2, the laminated iron core 11 having the same dimensions as in Example 1 is used, and the general steel sheet is also used as the electromagnetic steel sheet. Further, the measurement position of the excitation position, the excitation frequency and the vibration level were also the same as in Example 1. The Si content is 2.0 to 4.5% by mass.

FIG. 6 is a graph of representative vibration values when the fastening force is changed. As the vibration representative value, the total sum Wout of N-fold components of fHz out of the frequency components in the time-series waveform of acceleration obtained by measuring with a vibration sensor with an excitation force of 20 N was used. Note that Wout was calculated from 15 acceleration frequency components and then averaged.

As shown in FIG. 6, because if the fastening force is 6N / cm ² is low vibration, proper fastening force was determined to 6N / cm ^2. Here, when the excitation force was changed to 30N and 40N and the same measurement was performed, the graph shifted up and down, but the case where the fastening force was 6 N / cm ² was low as in the case shown in FIG. It was a vibration.
[Example 3]

Example 3 of the present invention will be described. In Example 3, an appropriate fastening force was obtained according to Embodiment 3 described above.

In Example 3, the laminated iron core 11 having the same dimensions as those in Examples 1 and 2 was used, but a magnetic steel sheet having a lower iron loss than that in Examples 1 and 2 was used. The Si content is 2.0 to 4.5% by mass. The measurement position of the vibration position, vibration frequency and vibration level was the same as in Examples 1 and 2.

FIG. 7A is a graph of vibration representative values when the fastening force is changed. Wout / Fin ((m / s ² ) / N) obtained by frequency analysis of 15 points of acceleration (m / s ² ) and excitation force (N) with 20 N excitation force was used as the vibration representative value. . For Wout, an averaged value after calculation from 15 acceleration frequency components was adopted.

As shown to Fig.7 (a), since the case where fastening force is 8 N / cm < ² > is low vibration, appropriate fastening force was determined to be 8 N / cm < ² >. Here, when the excitation force was changed to 30N and 40N and the same measurement was performed, the graph shifted up and down, but the case where the fastening force was 8 N / cm ² was low as in the case shown in FIG. It was a vibration.

Similarly, FIG. 7B and FIG. 7C show Wout / Fin (((m / s) / N) or (obtained by frequency analysis of velocity (m / s) and displacement (m)). m / N)) is a representative vibration value. For Wout, an averaged value after calculating from the velocity or displacement frequency components at 15 points was adopted. Even when evaluated by speed and displacement, as shown in FIGS. 7 (b) and 7 (c), when the fastening force is 8 N / cm ² , the vibration is low, so the proper fastening force is 8 N / cm ² . It has been determined.

Hereinafter, the matters common to the present invention including the above embodiments will be supplemented.
A typical electrical steel sheet used for a laminated iron core is characterized by containing Si: 2.0 to 4.5% by mass. However, the invention of the present application is hardly affected by the specifications of the electrical steel sheet (including the specifications of the coating), and is not limited to this composition, and the type (for example, directional electrical steel sheet, non-oriented electrical steel sheet). Is not limited. For example, if a required characteristic for an iron core is satisfied, a general cold-rolled steel sheet can be used as an electromagnetic steel sheet. The size and shape of the electromagnetic steel sheet, the size and shape of the laminated core, and the lamination method (the number of laminated sheets and how to combine the electromagnetic steel sheets) do not particularly affect the application of the present invention.

The frequency of excitation is preferably fixed to a predetermined value. As the predetermined value, the use frequency of the target laminated core is preferable, and when the use frequency has a width, it is preferable to select and use at least one representative frequency. For example, it is conceivable to fix at least one of commercial frequencies of 50 Hz and 60 Hz. However, it is not limited to a use frequency, For example, you may select the unified frequency for the comparison with another laminated body core. As long as the frequency is realizable (for example, 50 Hz to 20 kHz as described above), the absolute value of the frequency is not particularly limited. A sinusoidal wave is suitable for the excitation waveform, but it does not exclude application of other periodic waveforms such as a triangular wave and a rectangular wave.
The vibration position and vibration level measurement position on the laminated core can be arbitrarily set, and in principle, the result can be obtained at any position.

When determining the fastening force for reducing the noise after exciting (magnetizing) the laminated core from the relationship between the obtained vibration level and the fastening force (that is, when energizing the core), for example, the vibration level is the lowest. The fastening force to be obtained may be selected from the measurement points. However, as can be seen from FIGS. 5 to 7, in the region where the vibration reduction effect due to the sliding friction appears, the change in the vibration level becomes concave with respect to the change in the fastening force, and within this region (for example, 5 to 5 in FIGS. 5 and 6). In the region of about 7 N / cm ² , and in the region of about 6 to 8 N / cm ² in FIGS. 7A to 7C), it is considered that the noise reduction effect found in the present invention is sufficiently exhibited. Therefore, regardless of the minimum value of the vibration level, from the relationship between the obtained vibration level and the fastening force, specify the fastening force region where the vibration and noise reduction effect due to sliding friction is manifested, and take into account the various requirements. The fastening force can be selected as appropriate.

Examples of the range in which the fastening force is changed include a range that is possible for the target laminated core, a normal range, and a range that is appropriately extracted from these ranges. The range in which the fastening force is changed and the increment of the change can be specified from the relationship between the obtained vibration level and the fastening force to the extent that there is a fastening force region where the vibration / noise reduction effect due to sliding friction appears as described above. Just choose. In general, it is preferable to select appropriately from the range of about 5 to 20 N / cm ² .

For example, two or more of displacement, speed, and acceleration may be adopted as the vibration level. If the relationship between the vibration level and the fastening force varies depending on the selection of the vibration level, the most appropriate relationship may be determined based on the result of actually manufacturing the laminated core.

Note that the influence of the movement of the resonance peak due to the change in the fastening force (for example, the increase in the vibration level due to the proximity of the peak position to the measurement frequency) was not clearly observed as far as the inventors investigated. In other words, it is considered that the vibration level damping effect by the sliding friction of the present invention is more dominant than the influence of the movement of the resonance peak position that is originally complicatedly overlapped. It was not.

Needless to say, the present invention is not limited to the above-described embodiments and examples. For example, the mechanism for applying the fastening force is not limited to the springs shown in FIGS.

According to the present invention, there is provided a relatively simple, highly accurate and versatile method for reducing vibration and noise of a laminated core.

11 Laminated iron core (model)
12 Bakelite 13 Spring 21 Signal generator 22 Exciter 23 Load cell 24 Vibration sensor 25 Frequency analyzer 26 Frequency analyzer k Spring coefficient in one-degree-of-freedom vibration system (based on one-mass system model)
c Damping coefficient in one-degree-of-freedom vibration system (by one-mass system model)
m Mass of mass point in 1-DOF vibration system (by 1-mass system model)

Claims

A laminated iron core is constructed using electromagnetic steel plates, and with different fastening forces, it is vibrated with a mechanical excitation force within the range of 1N to 1000N, and the vibration level at one or more locations of the laminated iron core is measured. A method for determining a fastening force of a laminated core, wherein a fastening force for reducing noise is determined after exciting the laminated core by obtaining a relationship between a vibration level and a fastening force based on a measurement result of the vibration level.
2. The laminated core according to claim 1, wherein as the vibration level, an amplitude RMS value or an amplitude maximum value of a time-series waveform at a measurement location is calculated, and a representative value or an average value of the amplitude RMS value or the amplitude maximum value is used. Fastening force determination method.
The lamination according to claim 1, wherein the vibration level is obtained by frequency-analyzing a time-series waveform at a measurement location, calculating a sum total of frequency components N times the excitation frequency, and using a representative point value or average value. A method for determining the fastening force of the body core.
As the vibration level, frequency analysis is performed on the time-series waveform of the measurement location, the sum of frequency components N times the excitation frequency is calculated, the value of the representative point or the average value is set as Wout, and the excitation force is The fastening force determination method for a laminated core according to claim 1, wherein frequency analysis is performed, the sum of frequency components N times the excitation frequency is calculated, and Wout / Fin that is the ratio is used as Fin.
A method for manufacturing a laminated core, wherein a fastening force is determined using the method for determining a fastening force of a laminated core according to any one of claims 1 to 4, and the laminated core is manufactured by fastening with the determined fastening force. .