JP5455762B2 - Rotating electric machine and manufacturing method thereof - Google Patents

Description

  The present invention comprises a stator having a plurality of teeth portions formed by laminating electromagnetic steel sheets and spaced apart in the circumferential direction, and an annular yoke portion serving as a main magnetic flux path connecting the teeth portions. The present invention relates to a rotating electrical machine including an outer frame fitted to the outer peripheral surface of the stator, and a manufacturing method thereof.

In an electric motor, which is a rotating electric machine, in order to improve the transmission of the generated torque, the stator core block divided into a plurality of parts as an embodiment of the present application is arranged in an annular shape to form a stator. In order to improve the formability (roundness), an outer frame made of iron or aluminum is fitted on the outer peripheral surface of the stator.
As this fitting means, a method using the difference between the outer diameter of the stator and the inner diameter of the outer frame, for example, a method such as shrink fitting or press fitting is employed.
In this case, a large compressive stress acts in the circumferential direction of the yoke portion, and the magnetic properties (iron loss and magnetization properties) of the yoke portion are deteriorated, and accordingly, the motor performance (loss torque, efficiency) is deteriorated.
As a countermeasure, an example in which a gap or a notch for dispersing the compressive stress in the yoke portion is provided in the stator (for example, refer to Patent Document 1), or an example in which a steel material with little deterioration in magnetic properties under the compressive stress condition is used (for example, Patent Document 2) has been proposed.

  In the stator having a plurality of teeth portions in the circumferential direction shown in FIG. 1 of Patent Document 1, the stator outer peripheral portion is disposed between the teeth base portion and the stator outer peripheral portion in contact with the outer frame. A gap is provided to relieve stress in the vicinity, and the outer periphery of the stator where the teeth base is located is fixed in contact with the outer frame to reduce the compressive stress applied to the stator and suppress the deterioration of magnetic properties doing.

Moreover, the thing of the said patent document 2 provides the method of selecting an optimal electromagnetic steel plate in the use which a compressive stress acts on steel plate surface directions, such as a core fixed by shrink fitting.
In this case, an in-plane anisotropy index S is defined for the iron core for the above-mentioned use, and its value is 0.06 or less, and a non-oriented electrical steel sheet having in-plane magnetic properties close to isotropic is used. A method for selecting a magnetic steel sheet for an electric motor core, which is characterized by this, is shown.
Here, the in-plane anisotropy index S is the magnetic flux density B50 ⁰ , B50 ⁴⁵ , B50 ⁹⁰ excited and measured at a frequency of 50 Hz and a magnetizing force of 5000 A / m in the 0 °, 45 °, and 90 ° directions from the rolling direction of the steel sheet. Using the maximum value Bmax and the minimum value Bmin, the following formula is used.
S = 4 × (Bmax−Bmin) / (B50 ⁰ + 2B50 ⁴⁵ + B50 ⁹⁰ )

Japanese Patent Laying-Open No. 2005-354870 (page 8, FIG. 1) JP-A-2005-312155 (2nd page, 49th line to 3rd page, 17th line)

  However, although the thing of the said patent document 1 can reduce the stress added to a stator and can also improve fitting property with an outer frame, since the core width | variety in a teeth part base part is reduced, it is a load state of an electric motor. The magnetic flux density increases and iron loss increases, and when the stator is held only on the base of the teeth part, the teeth of the tooth part are separated by the deformation of the tooth part due to the stress from the outer frame. As a result, the roundness of the rotor-facing surface of the tooth portion is reduced, and the cogging torque is increased in the permanent magnet motor or the like.

Moreover, in the thing of the said patent document 2, generally the anisotropy in a plane becomes large in a rolling direction in an easy magnetization direction, so that a high grade non-oriented electrical steel plate with a small hysteresis loss is small.
Therefore, according to the selection in the above-mentioned Patent Document 2, the degree of freedom in device design is narrowed such that the normal high-grade material cannot be used, and there is a problem that the device performance is lowered and the product price is raised.

  An object of the present invention is to solve the above-described problems, and is not limited to a specific non-oriented electrical steel sheet as a material of the stator core, but as a stator core structure in the stator core. A rotating electrical machine that can suppress an increase in iron loss due to the effect of compressive stress generated in the circumferential direction of the stator core when the outer frame is mounted without providing a gap in the contact portion with the outer frame and a manufacturing method thereof It is.

A rotating electrical machine according to the present invention includes a plurality of teeth portions formed by laminating stator core pieces made of electromagnetic steel plates and formed at intervals in the circumferential direction, and a circle serving as a main magnetic flux path connecting the teeth portions. A rotating electrical machine comprising a stator including a stator core having an annular yoke portion, and an outer frame fitted to the outer peripheral surface of the stator,
The yoke portion is provided with plastic strain accompanying external stress exceeding the elastic limit and less than the yield point.

  In the method of manufacturing a rotating electrical machine according to the present invention, the plastic strain applied to the yoke portion is determined by pressing the stator core piece before the stator core piece is formed by the press forming process, or forming the stator core piece. And then applied by cold working.

  According to the rotating electric machine according to the present invention, the yoke portion is subjected to the plastic strain accompanying the external stress exceeding the elastic limit and less than the yield point, so that the compressive stress generated in the circumferential direction of the stator accompanying the outer frame mounting can be reduced. Increase in iron loss due to the effect is suppressed.

  Further, according to the method for manufacturing a rotating electrical machine according to the present invention, the plastic strain applied to the yoke portion is the step of pressing the stator core piece before the stator core piece is formed by the press forming process, or the stator. Since it is given by cold working after the iron core piece is molded, plastic strain can be easily given to the yoke part.

It is sectional drawing which shows the stator of the electric motor by Embodiment 1 of this invention, and the outer frame fitted by the outer peripheral surface. It is a figure which shows the relationship between the stress and distortion in an electromagnetic steel plate test material. It is a figure which shows the relationship between the amount of plastic deformation in a magnetic steel sheet test material, and an iron loss. It is a figure which shows the relationship between the amount of plastic deformation and the hysteresis loss under the elastic stress in an electromagnetic steel plate test material. It is a figure which shows the relationship between the amount of plastic deformation and eddy current loss under the elastic stress in an electromagnetic steel plate test material. It is a figure which shows the experimental result of this invention. It is a sectional side view which shows one process of the manufacturing process in the stator core of FIG. FIG. 8 is a plan view of FIG. 7. It is a front view of the punch of the press die used when shape | molding the teeth piece of FIG. It is a top view which shows the press work process different from the stator core of FIG. It is a top view which shows the process of providing the plastic strain to a yoke part which is the next process of FIG. It is arrow sectional drawing when cut | disconnecting along the XY line of FIG. It is a top view which shows the process of giving a plastic strain to the yoke part in the stator core (a teeth part and a yoke part are integral) different from the stator core of FIG. It is arrow sectional drawing when cut | disconnecting along the XY line of FIG. It is arrow sectional drawing when cut | disconnecting along the X1-Y1 line | wire of FIG. It is sectional drawing which shows the stator of the electric motor by Embodiment 2 of this invention, and the outer frame fitted by the outer peripheral surface. It is a figure which shows the state by which the stator core block of FIG. 16 was expand | deployed. It is a figure which shows the connection state of the adjacent stator core blocks of FIG. FIG. 17 is a side cross-sectional view showing a step of the manufacturing process for the stator core in FIG. 16. FIG. 20 is a plan view of FIG. 19. It is a front view of the stripper of the press die used when shape | molding the teeth piece of FIG. FIG. 20 is a side cross-sectional view showing one process of the manufacturing process different from the manufacturing process of the stator core shown in FIG. 19. It is arrow sectional drawing when cut | disconnecting along the XY line of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or equivalent members and parts will be described with the same reference numerals.
Embodiment 1 FIG.
1 is a cross-sectional view showing a stator 1 and an outer frame 6 of an electric motor according to Embodiment 1 of the present invention.
The stator 1 includes a stator iron core and a winding 4 wound around the stator iron core with a conducting wire wound through a bobbin 5.
The stator core is composed of an annular yoke portion 3 in which yoke pieces formed by press-forming non-oriented electrical steel sheets are laminated, and a plurality of tooth portions 2 in which teeth pieces obtained by press-forming non-directional electromagnetic steel plates are laminated. The root portion of each tooth portion 2 is fitted to the inner peripheral surface of the yoke portion 3 that becomes the main passage path of magnetic flux.

A cylindrical outer frame 6 made of iron or aluminum is fitted on the outer peripheral surface of the stator 1.
As a means for fitting the outer frame 6 to the stator 1, a difference between the outer diameter of the stator 1 and the inner diameter of the outer frame 6 is used to cool the stator 1. There is a cold fitting method. There is also a press-fitting method in which the stator 1 is press-fitted into the outer frame 6.
The yoke part 3 is provided with plastic strain accompanying external stress exceeding the elastic limit and less than the yield point.
Thus, since low plastic strain is applied only to the yoke portion 3, the hysteresis loss is equal and the eddy current loss is small and the compressive stress is less than that of the yoke portion not applied with plastic strain. Even if it is unevenly distributed, the eddy current loss is uniformly distributed.
For this reason, the iron loss, which is the sum of hysteresis loss and eddy current loss, can be reduced compared to the unstrained yoke part, despite the fact that compressive stress is acting, and the eddy current loss at the stress concentrated part. Local heating can also be suppressed. In particular, when operating at high speed rotation, the effect of reducing iron loss is greater, and the efficiency of the motor is improved.
Further, since it is not necessary to form a gap or the like for reducing the compressive stress from the outer frame 6 in the inside or the outer periphery of the stator 1, the holding force is improved between the outer frame 6 and the stator 1, and the yoke portion 3. Since the magnetic path cross section of the motor is not reduced, there are effects such as an increase in the magnetic flux density due to the load state of the motor and the suppression of the increase in iron loss and the roundness at the tip of the teeth portion 2 of the stator. can get.

Hereinafter, the characteristics of the yoke part 3 will be described in detail because the yoke part 3 is subjected to plastic strain accompanying external stress exceeding the elastic limit and less than the yield point.
First, for the non-oriented electrical steel sheet that is the material of the stator 1, the relationship between the application of plastic strain and the effect of iron loss, and further the state where the elastic stress is applied parallel to the magnetic path in the steel sheet surface The results of studying the relationship with the iron loss effect will be explained.
For imparting plastic strain to the non-oriented electrical steel sheet, a plurality of base plates having different strain amounts were produced by a method of pulling a flat plate in parallel with the rolling direction until a predetermined elongation rate was obtained. The electrical steel sheet used for the measurement is JIS grade 35A230 material, and the stress / strain curve according to JIS No. 5 is shown in FIG. A strip-shaped sample having a width of 30 mm and a length of 200 mm was cut out by wire electric discharge machining from the plastic strain uniform strain portion of the produced base plate and subjected to magnetic measurement.
Magnetic measurement is performed with a single yoke type single-plate magnetic tester with a stress application mechanism, applying elastic stress in the range of ± 150 MPa in parallel to the magnetic measurement direction to the cross section of the test piece, with magnetic flux sine wave conditions, excitation magnetic flux density 1.5T. In addition to measuring iron loss at excitation frequencies of 50 Hz, 70 Hz, and 100 Hz, frequency separation was performed based on these results, and hysteresis loss and eddy current loss in terms of 50 Hz were obtained.

First, the relationship between the application of plastic strain and the effect of iron loss is shown in FIG.
FIG. 3 shows the rate of change of each iron loss component when the value of hysteresis loss and eddy current loss of an unstrained sample is 1. The hysteresis loss increases as plastic strain is applied, while the change in eddy current loss shows a slight decrease, but it can be regarded as unchanged compared to the change in hysteresis loss. The sudden change of hysteresis loss with respect to plastic strain occurs in the low plastic strain region of less than 1%, and the upper limit of the strain is plastic strain generated by the stress at the yield point (≈0.2% proof stress) in the stress-strain curve. It can be easily inferred from the comparison of both data.

Next, the influence of iron loss when elastic stress is applied to the sample piece is shown in the figure. FIG. 4 shows a comparison result of hysteresis loss, and FIG. 5 shows a comparison result of eddy current loss. In the symbol of ± of the horizontal axis elastic stress, negative indicates compressive stress and positive indicates tensile stress.
First, regarding the hysteresis loss, in the state where no stress is applied, as described above, an unstrained sample having a strain of 0% has the smallest hysteresis loss, and the hysteresis loss increases as the plastic strain increases. When compressive stress is applied, the hysteresis loss increases with increasing compressive stress in both the unstrained sample and the strained sample, but the hysteresis increase in the range of 0 to −50 MPa is particularly large in the unstrained sample.
On the other hand, the increase amount in the sample subjected to plastic strain is smaller than that in the unstrained sample, and is a substantially constant change regardless of the strain amount. For this reason, when a compressive stress exceeding −50 MPa is applied, the non-strained sample and the value of 0.1% strain are substantially equivalent.
On the other hand, the amount of change in eddy current loss under compressive stress greatly changes due to the application of plastic strain. In the sample to which plastic strain is applied, the increase in eddy current loss with respect to compressive stress is small, and in particular, in the range of 0 to −50 MPa, there is no tendency for a large increase in eddy current loss as in the unstrained sample.

Thus, the inventor of the present application has found that the application of plastic strain has the effect of suppressing deterioration of eddy current loss due to compressive stress.
Therefore, if the balance between hysteresis loss and eddy current loss under compressive stress is controlled by the amount of plastic strain applied, iron due to compressive stress generated in the yoke portion 3 when the stator 1 is fitted to the outer frame 6 will be described. I thought I could reduce the loss increase.
The hysteresis loss in FIG. 4 and the eddy current loss in FIG. 5 are converted to 50 Hz, but each loss component value can be read as the magnitude of the loss coefficient because of loss separation by primary linear approximation.
If there is no great difference in the hysteresis loss coefficient and the eddy current loss coefficient is small, the iron loss that occurs in the stator core can be kept low as the excitation frequency increases, that is, the motor operates at high speed.
Therefore, it is necessary to limit the plastic strain that can be imparted to the upper limit of the plastic strain accompanying external stress below the yield point shown in FIG.

A sample imparted with 0.1% plastic strain is the subject of the present invention, and its effect is shown in FIG.
In FIG. 6, the iron loss at 50 Hz and 100 Hz with 1.5T excitation at a compressive stress of −50 MPa was compared. Since the increase in eddy current loss was suppressed in the plastic strain 0.1% sample, the higher the frequency, the larger the iron loss difference compared to the plastic strain 0% sample, and the lower iron loss. it is obvious.

Next, a procedure for manufacturing the stator 1 will be described.
7 and 8 are views showing a press forming process for producing the annular yoke piece 3a from the hoop material 7 which is a base material made of an electromagnetic steel plate.
In the pre-process of this press molding process, there is an extension / compression process in which a pair of upper and lower rolling rollers 8 of the hoop material 7 is used and the hoop material 7 is elongated in the longitudinal direction and compressed in the plate thickness direction. In this expansion / compression process, a predetermined plastic strain is applied to the hoop material 7 in advance.
Then, the yoke piece 3a is punched out by press molding from the plastic strain imparting portion 9 to which plastic strain is imparted in the pre-molding step, and separated from the hoop material 7 which is the base material of the electromagnetic steel sheet.
Next, the yoke pieces 3a are stacked and integrated to manufacture the annular yoke portion 3.

The annular yoke portion 3 to which plastic strain is imparted is manufactured by the above procedure, but the strain amount imparted can be easily inspected by a method such as X-ray diffraction.
For example, when an X-ray having a wavelength λ is irradiated on a polycrystalline body and scattered by an atomic plane having an inclination θ and a distance d, reflection occurs at a reflection angle θ when the Bragg condition is satisfied. At this time, the diffraction line is obtained at an angle of 2θ with respect to the incident direction, and if the atomic plane serving as the diffraction plane is deformed by Δd, the fluctuation of the diffraction angle associated therewith is given as follows.

  2Δθ = 2tAnθ · Δd / d

  The measurement of the strain Δd / d in the sample is performed by irradiating the sample surface that is moderately separated from the press working end of the yoke part to be inspected and having little influence of the press working strain and reflecting in the direction close to the X-ray source. What is necessary is just to use the back reflection method which investigates the position of the diffraction line to be performed. The calibration of the measured value may be performed by placing a comparative sample having a known lattice constant and Bragg angle close to the surface to be inspected and simultaneously measuring it.

On the other hand, the teeth portion 2 is manufactured in a process different from the manufacturing process of the yoke portion 3.
In the manufacture of the tooth portion 2, the teeth pieces are punched out by press molding from a hoop material made of an electromagnetic steel sheet not subjected to the above-described stretching / compression process, that is, given a predetermined plastic strain, and separated from the hoop material. .
Thereafter, the teeth pieces are laminated and integrated to manufacture the tooth portion 2.
The yoke piece 3a and the teeth piece constitute a stator core piece.
Next, a conductive wire is wound around each tooth portion 2 to wind the winding 4, and finally the root portion of each tooth portion 2 around which the winding 4 is wound is fitted to the inner peripheral portion of the yoke portion 3.

FIG. 9 is a front view showing a punch 10 for punching the entire teeth piece by one-shot press forming. A groove 11 is formed on the inner peripheral portion of the electromagnetic steel plate contact surface of the punch 10. This groove part 11 respond | corresponds to the site | part extended along the internal peripheral surface of the peripheral end surface of a teeth piece.
Therefore, the impact received from the punch 10 and the die (not shown) during the press working does not propagate to the inside of the tooth piece, and the deterioration of the magnetic characteristics due to the punching can be limited only to the vicinity of the punching end face. It is possible to suppress an increase in iron loss inside the tooth portion 2 where the pieces are laminated.

  On the other hand, in the case of performing punching without removing all of the teeth in a batch, the stripper and die (not shown) located above and below the green steel sheet to be processed By providing the groove portion with the same arrangement as in FIG. 9 on the electromagnetic steel plate contact surface side, it is possible to suppress the propagation of impact to the inside of the teeth portion 2 received from the punch 10 and the die during punching, as in the case of integral punching.

10 to 12 are plan views showing a press working step in another manufacturing method different from the stator core shown in FIG. 1, and FIG. 11 is a step subsequent to FIG. 10 and a step of applying plastic strain to the yoke portion 3. FIG. 12 is a cross-sectional view taken along the line X-Y in FIG. 11.
7 and FIG. 8, the plastic deformation is applied to the hoop material 7 which is the base material of the electromagnetic steel plate before the yoke piece 3a is pressed, and the production of the yoke piece 3a and the tooth piece is different. In this example, the yoke part 3 comprises a stator core piece from the point that plastic strain is applied to the yoke part 3 after the press process and the same hoop material 7 in the series of press process steps. It differs in that the piece 3a and the teeth piece are produced.

In order to give plastic deformation to the yoke part 3 in the steel plate surface, it can be performed by a drawing process which is a technique of cold working.
First, in order to pressurize the inner peripheral portion of the yoke portion 3 in the radially outward direction, as shown in FIG. 11, the collet-like stretching jigs 29 are equally arranged by the number of teeth portions 2 (12 pieces in FIG. 11). To do.
Next, the upper pressure bar 30A and the lower pressure bar 30B are lowered and raised from above and below the stretching jig 29, respectively. As a result, the stretching jigs 29 move along the guide rails 31 in the radial direction of the yoke part 3 and are brought into close contact with the inner wall surface of the yoke part 3, and then the yoke part 3 is stretched in the radially outward direction. Along with this stretching, a tension is generated in the yoke portion 3.
The direction of this tension is the same circumferential direction as the direction of magnetic flux flowing in the yoke portion 3 when the electric motor is in operation, and a predetermined plastic strain can be reliably applied to the circumferential direction of the yoke portion 3.
Finally, when the upper pressure bar 30A and the lower pressure bar 30B are raised and lowered, respectively, and the upper pressure bar 30A and the lower pressure bar 30B are released, the stretching jig 29 is moved inward by the elastic force of the guide spring 32. It is pushed back in the direction and separated from the yoke part 3.

For example, if the yoke 3 has an outer diameter of 107 mm, a width of 8 mm, and the height of the yoke 3 due to the stacked height of the yoke pieces 3 a is 80 mm, a stress of 400 MPa is generated in the circumferential direction of the yoke 3. Although it is necessary to apply a maximum force of 160 tons to the side surface of the yoke portion 3, a device having such a pressing capability is readily available.
In this example, the number of the stretching jigs 29 is the same as the number of the tooth portions 2 and is arranged uniformly in the circumferential direction. However, if the side surface of the yoke portion 3 can be evenly extended, it is arranged on the inner circumference of the yoke portion 3. The number of stretching jigs 29 to be stretched and the circumferential arrangement state are not limited to this.
In addition, the plastic strain is less than 0.2% at the maximum, and the elongation of the stator core accompanying the stretching is the same. For this reason, when the yoke part 3 is extended in the radial direction, the gap between the rotor and the stator 1 is also enlarged. However, the length of the tooth part 2 in the radial direction is increased in advance by the extension. The gap can be set to the value.

In the stator core described above, the tooth portion 2 and the yoke portion 3 are separate bodies. However, in FIGS. 13 to 15, plastic strain is applied to the stator core 50 in which the yoke portion 51 and the tooth portion 52 are integrated. An example is shown.
A stator core piece constituting the stator core 50 is produced from a hoop material 7 made of an electromagnetic steel plate by a pressing process.
Giving plastic strain to the stator core 50 can be performed by stretching, which is one method of cold working.
First, the extending jig 29 integrated with the lower collet jig 34B is inserted into each slot portion of the stator core 50 and brought into contact with the inner peripheral wall surface of the yoke portion 51. An upper collet jig 34A is fitted to the upper part of the stretching jig 29, and a lower collet jig 34B is fitted to the lower part of the stretching jig 29. The upper collet jig 34A is bonded and connected to one annular hard rubber plate 36 at a constant interval, and is movable in the radial direction and the circumferential direction.
Next, when the upper pressure bar 30A and the lower pressure bar 30B are lowered and raised, respectively, the upper collet jig 34A and the lower collet jig 34B are moved to the yoke portion 51 in conjunction with the movement of the pressure bars 30A, 30B. Move in the direction of the outer diameter. Accordingly, the stretching jig 29 also moves in the radially outward direction, and the yoke portion 51 of the stator core 50 is stretched in the radially outward direction.
Along with this stretching, a tension is generated in the yoke portion 51.
The direction of the tension is the same circumferential direction as the direction of the magnetic flux flowing in the yoke portion 51 when the electric motor is in operation, and a predetermined plastic strain can be reliably applied to the circumferential direction of the yoke portion 51.
Finally, when the upper pressure bar 30A and the lower pressure bar 30B are raised and lowered, respectively, and the upper pressure bar 30A and the lower pressure bar 30B are released, the stretching jig 29 is moved inward by the elastic force of the guide spring 32. It is pushed back in the direction and separated from the yoke portion 51 of the stator core 50.
Further, when the yoke portion 51 is extended in the radial direction, the gap between the rotor and the stator is also enlarged. However, by increasing the length in the radial direction of the tooth portion 52 in advance by the extension, the design value is obtained. Can be set to the gap.

  10 to 12, the yoke piece 3a is laminated and plastic strain is applied to the fastened yoke portion 3, and in FIGS. 13 to 15, the stator core piece is laminated and fastened. Although the configuration in which plastic strain is applied to the stator core 50 is shown, the yoke piece 3a before fastening, the stator core piece unit, or a plurality of yoke pieces 3a and stator core pieces are fastened for each block. Plastic strain may be applied in units of fixed iron core blocks.

If the number of stretching processes is small and there is a concern that the yoke piece 3a, the stator core piece, and the core block will be deformed in a direction perpendicular to the radial stretching force, a work piece presser such as a stripper in press working may be used. It is only necessary to prepare and secure the flatness of the yoke piece 3a, the stator iron core piece, and the iron core block.
According to such a method, a predetermined plastic strain can be applied to the circumferential direction of the yoke portions 3 and 51 regardless of the laminated fastening state of the stator core, and rather the number of pressurized sheets at the time of stretching is small. Needless to say, the force required for pressurization may be small, and the processing becomes easy.

Embodiment 2. FIG.
FIG. 16 is a cross-sectional view showing stator 1 and outer frame 6 of the electric motor according to Embodiment 2 of the present invention.
The stator core of the stator 1 is configured by welding and integrating adjacent stator core blocks 1A by spot welding or the like in a state where the stator core blocks 1A are arranged in an annular shape and constrained.
In the stator core block 1A, a tooth portion 2A and a yoke portion 3A are integrated.
The substantially T-shaped stator core block 1A is configured by stacking a plurality of stator core block pieces 1a in the thickness direction. This stator core block piece 1a is formed into a generally T-shape by press forming from a non-oriented electrical steel sheet in which a predetermined plastic strain is previously applied to a predetermined portion (a portion constituting the yoke portion 3A) in the extension / compression process. Is formed.
Other configurations are the same as those of the first embodiment.

Although the stator core block 1A is completely divided by the dividing surface 3c of the yoke portion 3, as shown in FIGS. 17 and 18, adjacent connecting portions 3d− of the stator core block pieces 1a. It goes without saying that it is very advantageous in terms of productivity if it can be supplied to the production line in a state where it is aligned and connected while leaving the degree of freedom of rotation in 1.
In the example of FIG. 17, the connecting portions 3d-1 at both ends in the circumferential direction of the stator core block piece 1a are thinly connected, and give a degree of freedom of rotation by plastic deformation.
In the example of FIG. 18, the concave portion 3d-2 and the convex portion 3d-3 are formed in the connecting portion 3d-1, and each stator core block piece 1a is alternately polymerized for each layer in the connecting portion 3d-1. And the recessed part 3d-2 and the convex part 3d-3 are fitting.

Even in the stator 1 of this embodiment, the same effect can be obtained as the iron loss improvement in the yoke portion 3 with respect to the compressive stress generated when the outer frame 6 is fitted as in the first embodiment.
If a plurality of stator core block pieces 1a are manufactured in a linearly aligned state, a predetermined low plastic strain can be easily applied to the yoke portion 3A of the stator core block 1A. It is.
Moreover, the effect which suppresses generation | occurrence | production of the harmonic iron loss accompanying magnetic flux distortion is also acquired in the site | part where 1 A of stator core blocks contact | abutted or it joined alternately.

Next, a manufacturing procedure of the stator core block 1A shown in FIG. 16 will be described.
FIGS. 19 and 20 are views showing a press forming process for forming the stator core block piece 1a from the hoop material 7 by press molding, which is one process for manufacturing the stator core block 1A.
In the pre-process of this press molding process, there is an extension / compression process in which a pair of upper and lower rolling rollers 8 of the hoop material 7 is used and the hoop material 7 is elongated in the longitudinal direction and compressed in the plate thickness direction. In this extension / compression process, the teeth piece 2Aa of the hoop material 7 is avoided, and a predetermined plastic strain is applied in advance to the plastic strain applying portion 9 corresponding to the yoke piece 3Aa.
In this example, a case where two rows of stator core block pieces 1a are manufactured is shown. Two rolling rollers 8 are arranged at symmetrical positions in the width direction of the hoop material 7, and the hoop material 7 is uniformly plastically strained. This prevents the axial line in the longitudinal direction from being eccentric with the plastic strain.
The rolling roller 8 may be arranged so that the axial line eccentricity of the hoop material 7 does not occur, and the number of the plastic strain applying portions 9 for applying the plastic strain in the width direction of the hoop material 7 is not limited to two. Absent.
Furthermore, the press forming of the teeth piece a is performed in the same process as the forming of the yoke piece 3Aa, and therefore, the outer peripheral portion of the teeth piece a is often divided into several steps and taken down.
In this shaping | molding, it extends inside the peripheral end surface of the teeth piece a, and along a surrounding surface to the electromagnetic steel plate contact surface inner peripheral part of the stripper 12 located in the upper part of the electromagnetic steel plate used as a workpiece shown in FIG. By providing the groove 11, impact propagation to the inside of the teeth piece a received from the punch and die during punching can be suppressed by the groove 11.
In FIG. 21, the groove 11 is formed in a single stroke, but even if a groove corresponding to only a portion where individual punching is performed is provided in the stripper 12, the obtained effect is not changed.
Then, a plurality of stator core block pieces 1a manufactured as described above are stacked in the thickness direction and integrated to manufacture a stator core block 1A.

  Moreover, in the said embodiment, although predetermined plastic strain was provided to the electromagnetic steel sheet by cold rolling before press forming, the stator core block 1A in which the yoke portion 3 of the stator 1 is divided by the yoke portion dividing surface 3c. 22 and 23, as shown in FIGS. 22 and 23, the same stretching as described in FIGS. 11 and 12 is performed directly in the circumferential direction of the yoke part 3, that is, plastic strain is applied to the electromagnetic steel sheet. It is possible to incorporate a mechanism using a tensile process, which is a technique of cold working to form a portion to be applied by applying a tensile stress in the in-plane direction, into the press die.

In FIG. 22, the outer peripheral slits 14 to 18 for separating the portion 13 that gives the plastic strain including the yoke portion to the hoop 7 and the holes 19 to 20 at both ends of the portion 13 that gives the plastic strain are press-molded. The left pulling jig 22 and the right pulling jig 23 incorporated in the upper mold 21 are inserted into the holes 19 to 20.
The left and right pulling jigs 22-23 move to the left and right via springs 24-25.
When the upper mold 21 is lowered, the left and right pulling jigs 22 to 23 abut against two pulling jig moving guide holes 27 to 28 provided in the lower mold 26 and move left and right.
With the movement of the pulling jigs 22 to 23, an in-plane tensile stress is applied to the portion 13 to which plastic strain is applied, and predetermined plastic strain can be easily applied.
After imparting plastic strain, the outer periphery of the stator core block piece 1a is cut off by press molding, and then the stator core block piece 1a is laminated in the thickness direction to complete the stator core block 1A.

  In the press molding of the outer peripheral portion of the teeth piece a of the stator core block piece 1a, the punch 10 having the groove portion 11 or the stripper 12 described in the first and second embodiments is used, so that the inner peripheral portion of the teeth portion is formed. The impact at the time of punch and die punching can be reduced, and deterioration of the magnetic properties of the inner peripheral portion of the teeth can be suppressed.

  In each of the above embodiments, the electric motor has been described as the rotating electrical machine. However, the present invention can also be applied to a generator that is a rotating electrical machine.

  1 Stator, 1A Stator Core Block, 1a Stator Core Block, 2, 2A, 52 Teeth, 2Aa Teeth, 3, 3A, 51 Yoke, 3a, 3Aa Yoke, 6 Outer Frame, 7 Hoop Material , 29 Stretching jig, 30A upper pressure bar, 30B lower pressure bar, 31 guide rail, 32 guide spring, 34A upper collet jig, 34B lower collet jig, 50 stator core.

Claims (8)

A stator having a plurality of teeth portions formed by laminating stator core pieces made of electromagnetic steel sheets and spaced apart in the circumferential direction, and an annular yoke portion serving as a main magnetic flux path connecting the teeth portions. A stator including an iron core;
A rotating electrical machine including an outer frame fitted to the outer peripheral surface of the stator,
The rotating electrical machine according to claim 1, wherein the yoke part is provided with plastic strain accompanying external stress exceeding an elastic limit and less than a yield point.   2. The rotating electrical machine according to claim 1, wherein the yoke portion and the tooth portion are divided and configured, and the tooth portion is fitted to an inner peripheral surface of the yoke portion.   2. The stator core according to claim 1, wherein a plurality of T-shaped stator core blocks configured by dividing the yoke portion between adjacent tooth portions are connected to each other. The rotating electrical machine described in 1.   The rotating electrical machine according to claim 1, wherein the rotating electrical machine is an electric motor. A method of manufacturing a rotating electrical machine according to any one of claims 1 to 4,
The method of manufacturing a rotating electrical machine, wherein the plastic strain is applied by cold working before the stator core piece is formed by a press forming process. A method of manufacturing a rotating electrical machine according to any one of claims 1 to 4,
The method of manufacturing a rotating electrical machine, wherein the plastic strain is applied by cold working in a step of forming the stator core piece by a press forming step. A method of manufacturing a rotating electrical machine according to any one of claims 1 to 4,
The method of manufacturing a rotating electrical machine, wherein the plastic strain is applied by cold working after the stator core piece is formed by a press forming process. A method for manufacturing a rotating electrical machine according to any one of claims 5 to 7,
In the press forming step, a punch or stripper having a groove formed at a position corresponding to a portion that is in contact with an unformed steel plate as a workpiece and extends along the peripheral surface inside the peripheral surface of the teeth portion is provided. The method of manufacturing a rotating electrical machine, wherein the tooth portion is formed by press-off using a press die provided.

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