JP3028406B2 - Manufacturing method of laminated magnetic core - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated magnetic pole core used for a stator or a rotor of an electric motor,
In the material processing stage and the shape processing stage, a heat treatment process for removing internal residual stress retained in the strip or the magnetic pole piece is provided,
The present invention relates to a method for manufacturing a laminated magnetic pole core that suppresses release of internal residual strain that is retained in a constrained state by removing internal residual stress that remains in a magnetic pole piece.

[0002]

2. Description of the Related Art Conventionally, a laminated magnetic pole core used for a stator or a rotor of an electric motor generally includes a progressive die apparatus in which a plurality of shape processing stations are integrally arranged in an appropriate order.
A tandem mold device divided for each shape processing station is installed, and in a press working process consisting of a plurality of press stations arranged in a tandem shape in an appropriate working order, a strip material slit to a predetermined width is processed. The required shape of the magnetic pole piece having the swaging projection is formed by intermittently transporting between the press stations and sequentially punching and removing unnecessary portions of the strip. And while performing the punching which forms the outer shape of this magnetic pole piece, by the unevenness of the crimping projection,
It is formed by laminating the pole iron pieces to a predetermined thickness in the press station.

[0003] However, when the slit is formed, a compressive stress is generated on the slit edge side of the slit and a tensile stress is generated in an intermediate portion of the width of the slit when the slit is formed. It has been known. Then, internal residual strain (apparent strain) in the elastic deformation range in the restrained state stays in this strip. When a magnetic pole piece used for a stator or a rotor of an electric motor is punched and formed from such a material, for example, a slot portion or a center circular hole of a stator or a rotor is punched and removed to form a magnetic pole piece. When the required shape is formed, the restrained state of the material at that portion is released, the balance of the internal residual stress is lost, and the internal residual strain in the strip is released. Then, the pole core piece extends in the width direction,
Punching distortion, which is caused by contraction in the feed direction, occurs, and minute deformation occurs at the tip of the magnetic pole tooth and the central bore. For this reason, the minute gap between the stator and the rotor of the motor (normal motor
1-0.3mm (piece), 0.025-0.0mm for stepper motor
(5 mm (piece)), causing a problem that the uniformity of the gap is lost and the characteristics of the electric motor are deteriorated.

Further, a compressive stress and a tensile stress are also generated around the central circular hole and the punched peripheral portion of the slot, and a new internal residual strain in the elastic deformation range is retained in the magnetic pole piece in a restricted state. Then, there is a problem that the internal residual strain is released by a subsequent processing step, heating, vibration or the like after assembling, thereby deteriorating the long-term reliability of the electric motor.

Further, when the punched magnetic pole core pieces are fitted and fixed by the concave and convex portions of the caulking projections, internal residual strain in a restricted state and a gap between the magnetic pole core pieces are generated around the cut and bent portions of the concave and convex portions. There is a problem that the magnetic properties are deteriorated.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and suppresses the release of internal residual strain that is retained in a locked state in a laminated magnetic pole core for a stator or a rotor of an electric motor. It is another object of the present invention to provide a method for manufacturing a highly accurate laminated magnetic pole core having excellent long-term reliability by uniformly forming and maintaining a fine gap (air gap) between a stator and a rotor of an electric motor.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for restraining internal residual strain (strain in a range of elastic deformation) generated in a step of forming a strip upstream of a pressing process. The first heat treatment step for removing the internal residual stress as it is, and the internal residual strain generated in the first shape processing step immediately before the second shape processing step is restrained by the annular connecting piece. A second heat treatment step for removing the internal residual stress is provided. Further, upstream of the first heat treatment step, a strip material correcting step for dispersing and equalizing the internal residual strain is provided. With such a configuration, the internal residual stress retained in the strip is removed, and the release of the internal residual strain retained in the laminated magnetic pole core of the stator or the rotor of the electric motor in a restricted state is suppressed. Can be.

Further, in the first shaping step, there is provided a shaping station for forming a desired shape of the magnetic pole piece except for an annular connecting piece connecting the tip portions of the magnetic pole teeth of the stator and the rotor, After passing through the second heat treatment step, the annular connecting piece is removed. With such a configuration, the internal residual stress can be removed in a state where the internal residual strain is restrained by the annular connecting piece.
As a result, the position size and shape of the magnetic pole teeth and the center inner diameter hole of the magnetic pole core can be maintained in the initial state.

The first shaping step includes a shaping station for alternately forming a first magnetic pole piece and a second magnetic pole piece in which crimping projections and through holes are alternately arranged. And a press station. With this configuration, the first and second magnetic pole pieces can be fitted and fixed alternately by a combination of a through hole and a crimping projection. As compared with the conventional combination of the projections and depressions of the caulking projection, the generation of the internal residual strain due to the fitting and fixing can be suppressed. Further, the adhesion between the magnetic pole core pieces of the laminated magnetic pole core can be improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, a first heat treatment step is provided upstream of a press working step, and a first shape working station (in this embodiment, five press stations are provided) in the press working step. ) And a second shape processing station (in this embodiment, two press stations are provided), and a second heat treatment step is provided. Here, the arrangement of the first heat treatment step is provided so as to be connected to the press working step via a loop device. Further, in the first shaping step, it is desirable to provide a press station for forming a center inner diameter hole so as to leave an annular connecting piece so as to connect the tip portions of the magnetic pole teeth of the magnetic pole piece.

Further, in the first shape processing step, a required shape of the first magnetic pole piece in which the crimping projections and the through holes into which the crimping projections are fitted are alternately formed is formed intermittently. Required shape of the second magnetic pole piece in which the press station to be formed and the through-hole at the position of the caulking protrusion formed on the first laminated magnetic pole piece, and the caulking protrusion at the position of the through-hole are alternately arranged Is provided intermittently.

In addition, it is effective to arrange a strip straightening step provided with a straightening leveler device for dispersing and equalizing the internal residual strain in the restrained state remaining in the strip, upstream of the first heat treatment step. is there.

Preferably, the second heat treatment step is arranged immediately before the press station for removing the annular connecting piece.

When a material having the internal residual strain in the restrained state generated in the material processing stage is supplied to the manufacturing process of the laminated magnetic pole core configured as described above, first, in the first heat treatment process, The internal residual stress is removed in a state where the internal residual strain retained in the strip material processing stage (slitter processing) is restrained. Then, in the second heat treatment step, the internal residual stress is removed while the internal residual strain retained in the first shape processing step (shape forming processing of the magnetic pole piece) is restrained by the annular connecting piece. Work like that.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a laminated magnetic pole core for a motor stator will be described below with reference to the accompanying drawings. 1 (a), 1 (b), 1 (c) and 1 (d) are explanatory diagrams and diagrams showing an outline of a manufacturing process of a laminated magnetic pole core of a motor stator according to an embodiment of the present invention. 2 (a) and 2 (b) are plan views showing an intermediate shape of a pole iron piece formed by stamping a strip material, and FIG. 3 is a cross-sectional view showing a laminated state of a pole iron piece forming a laminated magnetic pole core.

According to FIG. 1, the step of manufacturing the laminated magnetic pole core 100 (see FIG. 3) of the stator for the electric motor, which is an example of the embodiment of the present invention, is performed by pressing as shown in FIG. Upstream of the processing process, a strip material correcting process 10 for uniformly dispersing the internal residual strain retained in the strip material M generated in the strip material forming stage in a constrained state, and the dispersion uniformed internal residual strain is constrained A first heat treatment step 11 for removing the internal residual stress as it is, and as shown in FIG. 1B, a component of the laminated magnetic pole core 100 for a stator is provided downstream of the first heat treatment step 11. First to fifth presses equipped with a tandem mold device D for forming a required shape provided with an annular connecting piece 14 (see FIG. 2A) for connecting the magnetic pole teeth 13 of a certain magnetic pole piece 12. FIG. 2 in which the stations 15 to 19 are arranged.
1A, a first shape processing step 20 for forming an intermediate shape, and as shown in FIG. 1C, a punching process is performed downstream of the first shape processing step 20 in this processing step. A second heat treatment step 21 for removing the internal residual stress in the pole core piece 12 while removing the internal residual stress retained in the constrained state by the annular connecting piece 14 (see FIG. 2A). As shown in FIG. 1 (d), downstream of the second heat treatment step 21, a process of removing the annular connecting piece 14 and punching and forming a tip of the magnetic pole tooth 13 of the magnetic pole piece 12 is performed. As shown in FIG. 2B, a sixth press station 22 for forming an intermediate shape and a process for forming an outer shape of the pole core piece 12 are stacked and fixed in order in the tandem mold apparatus D. Then, the laminated magnetic pole core 10 for the stator shown in FIG. It is the second shaping step 24 in which a seventh press station 23 are arranged to form a structure having a a. Hereinafter, the details of the stator manufacturing process will be described.

First, with reference to FIG. 1A, a first heat treatment step 11 for removing internal residual stress remaining in a strip material M slit to a predetermined width will be described.

First, in the straightening step 10,
According to the figure, a strip material M supplied from an unwinding device U wound with a strip material M that has been slit into a predetermined width and has a retained internal residual strain is conveyed to a conventional straightening device 25 (leveler). By passing through the plurality of straightening roller groups 26 arranged in the (device), the internal residual strain in the restrained state staying in the strip M is dispersed, and the internal residual strain is made uniform. Next, the strip material M in which the internal residual strain is made uniform is firstly used.
Is supplied to the bright annealing furnace 27, and a bridle roller group 28 arranged upstream and downstream thereof applies tension to the strip material M while preheating the heating section 27a and heating section 2 in the furnace.
7b, the internal residual stress is removed while the internal residual strain of the strip material M is restrained while continuously transporting the inside of the process of the cooling unit 27c. With this configuration, the internal residual stress is evenly removed while maintaining the flatness of the strip material M. Here, the heating temperature of the bright annealing furnace 27 varies depending on conditions such as the material of the strip, the thickness of the strip, the processing history, and the like, but it is preferably performed at 600 to 800 ° C.

Subsequently, referring to FIG. 1B, a first shape processing step 2 for forming a required intermediate shape of the pole iron piece 12 will be described.
0 will be described.

First, in the first press station 15, as shown in the figure, a pilot hole 29 functioning as a positioning of a post-processed strip is formed in the strip M supplied from the first heat treatment step 11. Separation formation in the strip width direction (Fig. 2
(See (a)), and the center inner diameter hole 30 of the pole iron core piece 12 is punched and formed. Here, this center inner diameter hole 3
In the case of No. 0, the shape forming processing is performed so as to leave the annular connecting piece 14 so as to connect the tips of the magnetic pole teeth 13 formed in the next step (see FIG. 2A).

Next, in the second press station 16, according to the drawing, the first press station 1
A required number of winding slot holes 32 (see FIG. 2A) are punched and formed along the center inner diameter hole 30 of the magnetic pole piece 12 in the strip material M formed in Step 5.

Next, in the third press station 17, the laminated magnetic core 100 is separated every time the required number of magnetic pole pieces 12 are stacked on the strip M formed in the second press station 16. Is performed, a predetermined number of through holes 33 (four in this embodiment) are intermittently punched to form the separating magnetic pole piece 12a. Here, when the third press station 17 is operating, the fourth press station 18 and the fifth press station 19 are not operating.

Next, in the fourth press station 18, according to the drawing, the third press station 1
7, a predetermined number of first caulking projections 34 that fit into the through holes 33 of the magnetic pole iron piece 12a for separation.
The first magnetic pole piece 12b in which (in this embodiment, four places) and a predetermined number of first through holes 36 (four places in this embodiment) into which the second caulking projections 35 are fitted are alternately arranged. Is formed intermittently (see FIG. 3). Here, when the fourth press station 18 is operating, the third press station 17 and the fifth press station
Station 19 is not operating.

Next, in the fifth press station 19, as shown in FIG.
8, the second through-hole 37 is alternately provided at a position corresponding to the first caulking projection 34, and the second caulking projection 35 is provided at a position corresponding to the first caulking hole 36. The formation of the required shape of the second magnetic pole core pieces 12b arranged intermittently is performed intermittently (see FIG. 3). And, on the strip,
The required shape shown in (a), with the annular connecting piece 14 connecting the tips of the magnetic pole teeth 13 remaining, is formed. Here, when the fifth press station 19 is operating, the third press station 17 and the fourth press station 18 are not operating.

Further, referring to FIG. 1C, the internal residual strain retained in the first shape processing step 20 is removed from the annular connecting piece 1.
The second heat treatment step 21 for removing the internal residual stress in the state restrained by step 4 (see FIG. 2A) will be described.

As shown in FIG. 2, in the second heat treatment step 21, the second heat treatment step 21 formed in the first shape processing step 20 shown in FIG.
(A) The strip material M having the internal residual strain confined by the annular connecting piece 14 shown in FIG. 1A is supplied into a second bright annealing furnace 38 and arranged upstream and downstream of the bright annealing furnace 38. The bridle / roller group 39 adds tension to the strip material M while preheating the heating section 38a and heating section 38a in the furnace.
b, the internal residual stress is removed in the second bright annealing furnace 38 while the internal residual strain is kept in a restricted state through the process of the cooling part 38c. With this configuration, the internal residual stress is removed while maintaining the shape and dimensions. Here, the heating temperature varies depending on the forming process such as the punching shape of the strip material, but is preferably performed at 430 ° C to 600 ° C.

Next, the second shape processing step 24 for forming the laminated magnetic pole core 100 will be described with reference to FIG.

First, according to the drawing, at a sixth press station 22, the annular connecting piece 14 is removed from the strip material M shown in FIG. 2A supplied from the second heat treatment step 21. Removal is performed, and processing for forming the tips of the magnetic pole teeth 13 shown in FIG. 2B is performed.

First, according to the drawing, at the seventh press station 23, the sixth press station 22
First, the outer shape of the separating magnetic pole piece 12a is punched from the strip material M shown in FIG. Subsequently, as shown in FIG.
a first magnetic pole piece 12b is punched out on the first magnetic pole piece 12a, and the first magnetic pole piece 1b is inserted into the through hole 33 of the separating magnetic pole piece 12a.
The first caulking projection 34 of 2b is fitted, and the magnetic pole piece for separation 12a and the first magnetic pole piece 12b are fitted and fixed.
Next, a second magnetic pole core piece 12c is punched on the first magnetic pole core piece 12b, and the first magnetic pole core piece 12a is cut out.
Of the second pole iron core piece 12b
The crimping projection 35 is fitted to the first magnetic pole piece 12a.
And the second magnetic pole piece 12b are fitted and fixed. Similarly,
The first magnetic pole piece 12a is placed on the second magnetic pole piece 12c.
Is fitted and fixed. This is sequentially performed to obtain the first magnetic pole iron piece 12.
a and the second magnetic pole core pieces 12c are alternately stacked and laminated to a predetermined thickness, and then the separating magnetic core pieces 12a are punched out to form the laminated magnetic core pieces 100 of the stator separately. Thereby, it is possible to suppress the stagnation of the internal residual strain in the constrained state in the laminated magnetic pole core 100 and to eliminate the gap between the magnetic pole core pieces to improve the adhesion.

Although the method of forming the laminated magnetic pole core for the stator of the electric motor has been described, the laminated magnetic pole core for the rotor can be similarly formed. It is also possible to simultaneously form the stator of the electric motor and the laminated magnetic pole core for the rotor. In this case, after forming the intermediate shape in which the pole pieces of the stator and the rotor are connected via the annular connecting piece 31 shown in FIG. 3, a heat treatment for removing the internal residual stress may be performed. Then, the magnetic pole iron pieces of the rotor are laminated, and then the magnetic pole iron pieces of the stator may be formed.

As described above, as a preferred embodiment of the present invention, a plurality of tandem mold apparatuses D divided for each shape processing station are mounted on each of a plurality of press stations, and these are tandemly formed in an appropriate order. Although the description has been given as a configuration including the arranged press forming steps, the respective press stations of the first shape forming step and the second shape forming step are respectively integrated, and the first shape forming step and the second shape forming step are performed. And a heat treatment step may be arranged between them.

[0032]

As described above, according to the present invention, after performing the slit processing for forming the strip and the first shape processing for leaving the annular connecting piece for connecting the tip of the magnetic pole tooth of the magnetic pole piece,
In any case, the internal residual stress is removed in the bright annealing furnace while the internal residual strain is restrained, so that the magnetic pole teeth are not twisted, and a magnetic pole piece with excellent positional dimensional accuracy can be formed. The gap (ear gap) between the stator core and the rotor core can be formed uniformly. In addition, since the first shape processing has a configuration in which a press station for alternately forming the first magnetic pole pieces and the second magnetic pole pieces is used, the magnetic pole pieces are formed by a combination of through holes and protrusions. Since the laminated magnetic pole core fixed and fitted is formed, the internal residual strain in the constrained state stagnated in the laminated magnetic pole core can be suppressed and the magnetic pole piece can be suppressed, as compared with the conventional combination of concave and convex. Adhesion between them can be improved. As a result, it is possible to provide a high-precision laminated magnetic core that maintains long-term reliability of the electric motor.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a manufacturing process of a laminated magnetic pole core of a stator according to an embodiment of the present invention.

FIG. 2 is a plan view showing an intermediate shape of a laminated magnetic pole piece of the stator according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a laminated state of laminated magnetic pole cores of the stator according to the embodiment of the present invention.

FIG. 4 is a plan view showing an intermediate shape of a laminated magnetic pole piece forming a stator and a rotor according to another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Laminated magnetic pole core of motor stator 10 Strip straightening process 11 First heat treatment process 12 Magnetic pole piece 12 a Separating magnetic pole piece 12 b First magnetic pole piece 12 c Second magnetic pole piece 13 Magnetic pole teeth 14 Ring connection Piece 15-19 First to fifth press station 20 First shape processing step 21 Second heat treatment step 22 Sixth press station 23 Seventh press station 24 Second shape processing step 25 Straightening processing Apparatus 26 Straightening roller group 27 First bright annealing furnace 27a Preheating section 27b Heating section 27c Cooling section 28 Bridle roller group 29 Pilot hole 30 Center inner diameter hole 31 Ring connecting piece 32 Winding slot hole 33 Through hole 34 First Projection for caulking 35 Projection for caulking 36 First through hole 37 Second through hole 38 Second bright spot Furnace 38a preheating unit 38b the heating portion 38c slow cooling unit 39's a Bridle roller group D tandem mold apparatus M cord member U winding device P stamping

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-269149 (JP, A) JP-A-57-31421 (JP, A) JP-A-1-190235 (JP, A) 288415 (JP, A) JP-A-61-268007 (JP, A) JP-A-60-208419 (JP, A) JP-A-4-101730 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) H01F 41/02 H02K 15/00-15/16 B21D 28/02

Claims (3)

(57) [Claims] 1. A plurality of tandem mold apparatuses each having a progressive mold apparatus divided and formed for each shape processing station are mounted on each of a plurality of press stations having independent press functions, and these are arranged in an appropriate order. A method for manufacturing a laminated magnetic core having a tandemly arranged press working step, wherein the press working step includes a first heat treatment step for removing internal residual stress accumulated in a strip material forming step upstream thereof. A first shaping step including a plurality of press stations for forming a desired shape of the magnetic pole piece while leaving an annular connecting piece so as to connect the tip portions of the magnetic pole teeth;
A second heat treatment step for removing an internal residual stress generated by the shape processing of the step (a), and a second shape processing step including a press station for removing the annular connecting piece. Manufacturing method of magnetic pole core. 2. The first heat treatment step includes the steps of:
2. The method for manufacturing a laminated magnetic core according to claim 1, further comprising a straightening process for dispersing and equalizing internal residual strain retained in the strip material in a restrained state. 3. The first shape processing step includes alternately forming required shapes of a first magnetic pole piece and a second magnetic pole piece in which a plurality of crimping projections and a plurality of through holes are alternately arranged. 2. The method for manufacturing a laminated magnetic core according to claim 1, wherein each of the press stations is provided with a tandem mold device to be formed.