JP2005300211A - Performance estimation method on worked iron core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a performance estimation method on a worked iron core for easily and highly accurately conducting performance evaluation so far performed only through actual measurement. <P>SOLUTION: As to a performance estimation method on worked magnetic materials and on an iron core into which the magnetic materials are combined, the performance of the worked iron core is estimated by using a function that expresses work degradation of a magnetic material by using a distance from a worked part. Further, as to a performance estimation method on worked magnetic materials and on an iron core into which the magnetic materials are combined, work degradation is divided between a plastic deformation area and an elastic deformation area; the magnetic characteristics of a specimen obtained by rolling the magnetic material are used for the plastic deformation area while averaged magnetic characteristics are used for the elastic deformation area, the averaged magnetic characteristic being obtained by averaging magnetic characteristics under tension and magnetic characteristics under compressive force of the same size as the tension. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for estimating iron core performance.

  Electromagnetic devices are required to be small, light and have low loss and high efficiency. Iron cores are required to have high permeability and low iron loss. For this purpose, an iron core material having high magnetic permeability and low iron loss is used. However, even if this high-performance iron core material is used, if punching is performed to obtain a predetermined iron core shape, the core material characteristics deteriorate due to the processing strain, and ultimately the performance of the electromagnetic equipment also deteriorates.

  For optimal design of electromagnetic equipment, magnetic circuit design is optimized by numerical analysis. However, as described above, there is a problem in that the accuracy of electromagnetic device performance estimation by numerical analysis is lowered due to processing deterioration of the core material.

  The present invention provides a method for estimating the performance of a processed magnetic material or a combination core thereof.

The feature of the present invention is that
(1) In a method for estimating the performance of a processed magnetic material and an iron core combining the magnetic materials, a method for estimating a processed iron core performance using a function representing processing deterioration of the magnetic material at a distance from the processed portion,
(2) In a method for estimating the performance of a processed magnetic material and an iron core combining the magnetic materials, the work deterioration is divided into a plastic deformation region and an elastic deformation region, and the magnetic material is rolled into the plastic deformation region. For the elastically deformed region, the performance of the processed iron core is estimated using the magnetic properties obtained by averaging the magnetic properties under tension and the magnetic properties under the compression force of the same magnitude as the tension with the same magnetic field. Method,
(3) In a method for estimating the performance of a processed magnetic material and an iron core combining the magnetic materials, the work deterioration is divided into a plastic deformation region and an elastic deformation region, and the magnetic material is rolled into the plastic deformation region. The processed iron core using the magnetic properties of [Excitation direction stress-(Sum of stresses in two directions perpendicular to the excitation direction) / 2] for the elastic deformation region using the magnetic properties of the sample. Performance estimation method,
(4) The estimation method of the processed core performance according to (2) or (3), wherein the estimation method according to (1) is used for each of the plastic deformation region and the elastic deformation region,
(5) When a processed magnetic material or a combined iron core is used after being subjected to strain relief annealing, the post-annealed iron core is obtained by using the method for estimating the machined iron performance according to any one of (1) to (4). Method for estimating machined core performance to estimate performance,
(6) About the performance of the electromagnetic device using the processed magnetic material or the combined iron core, the estimation of the electromagnetic device performance estimated using the method for estimating the machined core performance described in any one of (1) to (5) Is in the law.

  The method for estimating the performance of a processed iron core according to the present invention is based on numerical analysis, crystal grain deformation observation, magnetic domain observation, and hardness measurement of a processed part, based on magnetic properties of the magnetic material, magnetic properties of the rolled magnetic material, and magnetic properties. The core performance is estimated from the magnetic characteristics of the material when stress is applied, and the conventional machined core performance that can only be evaluated with high accuracy only by actual measurement is easily made possible with high accuracy. In the conventional estimation method, most of the evaluation was performed by evaluating the deteriorated part near the machined part and the normal part. However, in actuality, if the plastic deformation area and the elastic deformation area are not taken into account, the estimation cannot be performed accurately. By taking these into account, high-precision estimation was possible. In addition, this estimation method is performed by obtaining the deterioration distribution as a function of the distance from the processed part, and can be applied to a processed product of any shape, and is suitable for an actual motor core.

  Magnetic materials are Fe, Ni, Co or magnetic materials containing these, such as magnetic steel sheets, permalloy, and Fe-Co-V materials, electromagnetic soft iron, cast iron, Fe-Ni materials, Fe-Co-V. It is a lump-like or rod-like magnetic material.

  The iron core is a laminate or bundle of these, including those that are crimped or welded. The iron core is used as a transformer, an inductor, a filter, a sensor, or a magnetic shield used in energy conversion devices such as a transformer, a motor, a generator, a reactor, and an inductor, and an electronic electric circuit.

  Processing is stamping, shearing, bending, or electric discharge processing, laser processing, etching processing. From now on, these will be summarized and stamped and sheared.

  The distance from the processed portion is the shortest distance x from the processed portion, and a function representing the processing deterioration of the magnetic material is expressed using the x.

  When the magnetic material is punched and sheared, the portion closest to the processed portion is plastically deformed to form a sag or the like, and this plastic deformation region portion changes in magnetic properties and hardness. Therefore, the plastic deformation region is a portion where the shape such as the plate thickness is changed by processing, a portion where the crystal grain size is deformed in the processing cross-sectional photograph, or a portion where the hardness is changing, and is subjected to punching processing or shearing. This is a part where sagging or the like occurs in processing. In the case of bending, a plastic deformation region can be defined as described above. Electrical discharge machining and laser machining are treated as melted parts, and etching processes are treated as chemically deformed parts as plastic deformation. As a plastic deformation region, a portion deformed by more than 1/10 of the maximum plastic deformation rate, a portion where the hardness is increased within 1/10 of the hardness increase due to processing, a melting portion of electric discharge machining, laser machining, etc. The part where the crystal grain boundary is melted and the part where the etching process is chemically eroded are the part which is corroded. As shown in Example 1, 1/10 of the maximum plastic deformation rate in the plastic deformation region is a value at which the magnetic characteristic deterioration is almost saturated with respect to the plastic deformation, and the change in hardness is considered to be proportional thereto.

  The elastic deformation area is the area adjacent to the plastic deformation area connected to the machining end such as punching and shearing, and is the area affected by the elastic stress based on the deformation of the plastic deformation area. As shown in Example 1, this is a region that affects the magnetic domain structure. The width of this area is obtained by magnetic domain observation and numerical value calculation of machining stress, or converted from measured data, and based on this, it is applied to the same machining and similar machining performed on similar-shaped iron cores. be able to.

  As the magnetic characteristics used in the plastic deformation region, data on the cold-rolling strain of the magnetic material corresponding to the deformation rate within which the greatest deformation is processed is used throughout the plastic deformation region. Preferably, data of cold-rolling strain of the magnetic material corresponding to the average deformation rate in the plastic deformation region is used. For simplicity, cold rolling strain data of the magnetic material corresponding to 1/2 of the maximum deformation rate may be used. The deformation rate of each part may be used in a distributed manner, and the data f () deteriorated by cold-rolling work strain for each part deformation rate ε (x) by incorporating a representative deformation distribution as a function of the shortest distance x from the machining end. x) may be used to estimate the performance of magnetic materials, iron cores, and electrical equipment using these.

  The magnetic characteristics used in the elastic deformation region are the same in both the compression force and tension in the elastic deformation region. (Magnetic characteristics).) Or [Excitation direction stress-(Sum of two directions perpendicular to the excitation direction) / 2] Excitation direction stress. (Hereinafter referred to as magnetic characteristics of three-dimensional merger). The elastic stress of each part may be used in a distributed manner, and a representative elastic deformation distribution is incorporated into the function of the shortest distance x from the machining end, and the tension compression and compression for the tension and compression magnitude σ (x) of each part The magnetic property data g (x) of the three-dimensional merged magnetic properties may be used to estimate the performance of magnetic materials, iron cores, and electrical equipment using these.

The present invention can also be applied to a case where a processed magnetic material or a combination iron core is used after being subjected to strain relief annealing. In this case, the region recrystallized by the plastic deformation strain corresponds to the plastic deformation region. In this case, ε (x) of each part is influenced by the residual stress strain σ and the grain size D after recrystallization, and the residual stress strain is σ ₀ [1- exp (−T ₀ / T) · t / t ₀ ], and ε (x) is proportional to σ, or ε (x) is the crystal grain size before processing as D ₀ and 1 / D ^N − Assuming that it is proportional to 1 / D ₀ ^N , constants and proportional counts are obtained by experiments or actual measurement values. Separately, a product that has been cold-rolled may be annealed under strain relief annealing conditions, and the required magnetic property data may be f (x).

  Used to estimate the performance of electrical equipment using processed magnetic materials or combined iron cores. Electrical equipment is used in all electrical equipment and electromagnetic devices such as motors, generators, reactors, shield materials used in home appliances, factories, railways, automobiles, office equipment, and generators used in power plants and generators. Applicable.

An example of estimating iron core performance due to shearing deterioration and a method of estimating a magnetization curve will be given. Let B (x, H) be the magnetization curve at a distance x from the end in the magnetic field H, and B ₀ (H) be the magnetization curve without processing distortion. The region from the processing end to the distance w _P is a plastic deformation portion, and the magnetization curve of this region is constant.
B (x, H) = B _P (H) = 0.44 · ln (H) −2 (1)
And An area from the distance w _P to w _E from the machining end is defined as an elastically deformable portion.
B (x, H) = B _P (H) + {B ₀ (H) −B _P (H)} (x−w _P ) / (w _E −w _P )
... (2)
Assuming that If the processing width is measured magnetization characteristic of the whole sample is w, w> when 2w _E, the magnetization curve _{Ba (w) = [2B P} (H) w P + {B P (H) + B 0 (H )} (W _E −w _P )
+ B ₀ (H) (w−2w _E )] / w
= B ₀ (H) − [B ₀ (H) −B _P (H)] (w _P + w _E ) / w (3)
It becomes. Therefore, the average magnetic flux density at a constant magnetic field in the processing width w (mm) is expressed as Ba (w) = ba−w / (4)
As a result of measuring the magnetization curve by changing the shear width in an electromagnetic steel sheet having a thickness of 0.5 mm, it is determined based on FIG.
At a magnetic field H = 800 A / m, Ba (1.1) = 0.73T, Ba (1.6) = 0.85T, Ba (3) = 1.18T, Ba (6) = 1.42T, Ba ( 15) = 1.5T, so from regression analysis,
Ba (w) = 1.53-0.47 / w (5)
It becomes. When (w _P + w _E ) is obtained from the equations (3) and (5), it becomes w _P + w _E = 0.83 mm. Assuming that w _P is 0.25 mm as half the plate thickness, w _E = 0.78 mm.
Eventually, in the case of an electromagnetic steel sheet having a shear width w (mm), the magnetization characteristics after shearing can be estimated by the following equation.
Ba (w) = B ₀ (H) −0.83 [B ₀ (H) −0.44 · ln (H) +2] / w
... (6)

  In estimating the punching deterioration, the width of the plastic deformation region is determined by the width of the punched sag portion, and the elastic deformation width is determined from the magnetic domain observation result of the actual machine. FIG. 2 is a sag surface photograph of the processed part. The part where the crystal grains emerged was the plastic deformation part, and the plastic deformation width was half of the plate thickness. FIG. 3 is a photograph of the burrs side opposite to the sag side, where the punched portion of the punched mold is printed on the punched portion corresponding to the plastically deformed portion, and the plastic deformation width estimated from this photograph is the plate. It was half the thickness. From the above, the plastic deformation width was determined to be 1/2 of the plate thickness. Fig. 4 is a photograph of magnetic domains on the sag side and the burrs side. The thickness of the part giving influences on the mag- netic domains (the burrs side: the part where the domain wall interval is narrowed, the sag side: the part where the magnetic domains are clearly visible). The elastic deformation width was determined to be twice the plate thickness.

The magnetic properties and iron loss of the electrical steel sheet material properties were measured and designated as B ₀ (H) and W ₀ (B). The magnetic properties of the electrical steel sheet sheared to the same plate width as the plate thickness (twice the plastic deformation width) were measured, and from the results, the magnetic properties and iron loss of the plastically deformed portion were determined as B _P (H), W _P ( B). By measuring the magnetic properties of electrical steel sheet was sheared in a thickness of 5 times the width (twice the sum of twice the elastic deformation range of the plastic deformation range), the resulting magnetization characteristics and iron loss B _{PE (H} ), W _PE (B). From this, the magnetization characteristics of the elastically deformed portion and the average values B _E (H) and W _E (B) of the iron loss are
B _E (H) = {5B _PE (H) −B _P (H)} / 4
W _E (B _E (H)) = {5 W _PE (B _PE (H)) − W _P (B _P (H))} / 4
It can be expressed as

From the above, it is assumed that the magnetic properties of the distance x from the processed part by the estimation method of the present invention are uniform in the plastic deformation region and the elastic deformation region, respectively, and the thickness is t.
When x <t / 2, B _P (H), W _P (B)
When t / 2 ≦ x <2t, B _E (H), W _E (B)
When 2t ≦ x, B ₀ (H), W ₀ (B)
It was.

  Thick magnetic steel sheets were punched out to produce iron cores for 2-pole induction motors. In estimating the magnetic properties of this motor core, the shape deformation due to punching, residual strain (plastic deformation), and residual stress (elastic stress) are obtained by three-dimensional analysis. The effect of residual strain on magnetic properties is determined by rolling residual strain. For the residual stress, the excitation direction stress is defined as [Excitation direction stress-(sum of two directions perpendicular to the excitation direction) / 2] for the residual stress. Magnetic property data for the case was used. When the motor iron loss in an unloaded state was determined by this method, according to the estimation of the present invention, it was 1.31 times (iron loss in punched iron core) / (iron loss without strain). When the motor iron loss was measured in order to verify this estimation accuracy, it was 1.37 times (iron loss in punched iron core) / (iron loss in electric discharge machining), and was estimated with considerable accuracy. I understood.

An example in which the influence of machining deterioration on the magnetic properties of a ring core is estimated will be shown. Plastic deformation zone and the crystal grains deformed portion of the working portion, and the width w _P. The magnetic characteristic in which the rolling ratio is 1/2 of the ratio of the sagging size to the plate thickness was defined as the magnetic characteristic of this region. In the elastic deformation region, the stress σ can be expressed by σ _E exp {(w _P −x) / x _E } with respect to the distance x from the processed portion, and the magnetic characteristics are the average of the magnetic characteristics of the tension σ and the compressive force σ. did. As in Example 3, σ _E and x _E were obtained by calculation of residual stress in processing, and the maximum residual stress and stress residual area width were set as σ _E and x _E.

This method was applied to a ring having an outer diameter of 125 mm and an inner diameter of 100 mm punched from the non-oriented electrical steel sheet 50A1000. It was measured as the width of the crystal grains deformed portion of the processing unit, so there was a thickness of 1/3, w _P was 1/3 of plate thickness. Since the ratio of the sagging size to the plate thickness was 0.3 from the actual measurement, the average deformation rate in the plastic deformation region was set to 0.15 that is 1/2 of 0.3, and the magnetic property in the plastic deformation region was the rolling rate. It was set as the magnetic characteristic (rolling direction) rolled at 15%. The ring characteristics were estimated from the magnetic characteristics of the material and the magnetic characteristics rolled at a rolling rate of 15%. The actually measured iron loss was 15% deteriorated, but the estimated value was 18%.

  For Example 4, the plastic deformation region was determined from the hardness. The width increased by 5 points with micro Vickers in the portion of the plate thickness 1/2 was defined as the plastic deformation region. In the example, the width of the plastic deformation region was 0.44 times the plate thickness, and the estimated deterioration rate of the iron loss was 13%.

  An iron core of an EI core [working (magnetic path) width is 25 mm] obtained by processing a bidirectional magnetic steel sheet by wire cutting was estimated. When the magnetic domain was observed in the processed part, it was observed that the entire crystal grain processed in the processed part was oriented in the easy magnetization direction closest to the processing direction (perpendicular to the processed part). The magnetic properties of the processed crystal grains were estimated from the direction dependency of the magnetic properties of a sample in which a bi-directional electrical steel sheet was annealed in a magnetic field and magnetized in one direction. For example, when exciting in parallel to the machining part as in the EI core, if the easy magnetization direction closest to the machining direction is 5 ° from the machining direction, this easy magnetization direction is 85 ° with respect to the excitation direction. The magnetic properties of a bi-directional electrical steel sheet having an angle of 85 ° with respect to the annealing direction in the magnetic field are used. When the magnetic properties of the processed crystal grains in the processed portion were estimated by this method and the iron loss was estimated using the material properties for the other portions, the increase was 36%.

  The magnetic characteristic after the strain relief annealing of the ring iron core of Example 4 is estimated. Using the relationship between the recrystallized average grain size and the magnetic properties of the core material annealed after 5% cold rolling, which was investigated in advance, the change in magnetic properties after strain relief annealing in the plastic deformation region is the same as that after strain relief annealing. The magnetic properties are determined from the average crystal grain size of the plastic deformation part.

The elastic deformation region is due to strain relief annealing, assuming that the annealing temperature (K) and time (h) are T and t, and the residual stress is proportional to [1-t / t ₀ · exp (−T ₀ / T)]. Estimate changes in magnetic properties. In this example, t ₀ = 5.2 × 10 ⁻¹⁰ h, T ₀ = 21900K, assuming that distortion caused by machining is proportionally released at 700 ° C. for 3 hours and at 750 ° C. for 1 hour. When [1−t / t ₀ · exp (−T ₀ / T)] becomes negative, zero is used as the stress-free magnetic characteristic. When annealed at 650 ° C. for 5 hours, it was measured by the average grain size of the crystal grains in the plastically deformed portion, and the magnetic properties corresponding to the recrystallized average grain size after annealing of the 5% cold rolled material closest to the average grain size This is the magnetic property of the plastic deformation part. The magnetic permeability of the plastic deformation zone after annealing was still about 1/5 compared to the magnetic permeability of the raw material, but the magnetic flux passing through the plastic deformation zone was still lower than the magnetic permeability of the material with respect to the single digit permeability decrease without annealing. Remained low. On the other hand, the residual stress due to annealing in the elastic deformation region is 1-t / t ₀ · exp (−T ₀ /T)=0.50, and σ _E is halved. Therefore, the magnetic permeability (constant magnetic field) was about 70%, and the iron loss (constant magnetic flux density) was 50%.

  Based on these results, the iron loss recovery rate [= (iron loss after processing−iron loss after annealing) / (iron loss after processing−iron loss upon complete recovery)] in the entire iron core is estimated to be about 31%. It was. In actual measurement, about 25% of the iron loss deterioration was recovered, so that it was estimated with almost good agreement.

It is a diagram which shows the influence of the shear distortion which gives to a magnetization curve. It is a photograph of the sagging side surface of a processing part. This is a photograph of the Kaeri side opposite to the Dare side. It is a magnetic domain photograph of the Dare side and the Kaeri side.

Claims (6)

In a method for estimating the performance of a processed magnetic material and an iron core that combines the magnetic material, a method for estimating a processed iron core performance using a function that represents processing deterioration of the magnetic material by a distance from a processed portion. In the method of estimating the performance of the processed magnetic material and the iron core combining the magnetic material, the work deterioration is divided into a plastic deformation region and an elastic deformation region, and the sample of the sample obtained by rolling the magnetic material is applied to the plastic deformation region. A method for estimating the performance of a machined iron core using magnetic properties, and using magnetic properties obtained by averaging magnetic properties under tension and magnetic properties under a compressive force having the same magnitude as the tension with the same magnetic field for an elastic deformation region. In the method of estimating the performance of the processed magnetic material and the iron core combining the magnetic material, the work deterioration is divided into a plastic deformation region and an elastic deformation region, and the sample of the sample obtained by rolling the magnetic material is applied to the plastic deformation region. Estimating the machining core performance using magnetic properties using the magnetic properties and [excitation direction stress-(sum of two directions perpendicular to the excitation direction) / 2] / 2 for the elastic deformation region. Method. The method for estimating the performance of the processed iron core according to claim 2 or 3, wherein the estimation method according to claim 1 is used for each of the plastic deformation region and the elastic deformation region. When the processed magnetic material or the combined iron core is used after being subjected to strain relief annealing, the machining iron core performance after annealing is estimated using the method for estimating the processed iron core performance according to any one of claims 1 to 4. An estimation method of core performance. The estimation method of the electromagnetic equipment performance which estimates the performance of the electromagnetic equipment using the processed magnetic material or the combined iron core using the processing core performance estimation method according to any one of claims 1 to 5.

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