JP2001292541A - Laminated stack and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated stack that is provided with embosses giving no adverse effects on magnetic balance and thus greatly contributes to the improvement in the performance of electrical equipment. SOLUTION: Thin boards 11 and 15, comprising a plurality of stator stacks 2 or rotor stacks 7 with pole teeth arranged in the circumferential direction, are provided with round embosses 12 and 16, having a diameter of not more than 0.8 mm. When these round embosses 12 and 16 are machined, the amount of misalignment between a molding die and a punch is set to 3 μm or less. When the thin boards 11 and 15 are laminated together by fitting the round embosses 12 and 16 together, the engaged area between the round embosses 12 and 16 is prevented from biting so that the thin boards 11 and 15 are laminated densely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated stack used for various motors such as a stepping motor, a spindle motor, a fan motor and the like, a generator, a transformer and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art For example, a laminated stepping motor is
As shown in FIGS. 4 to 8, a stator 5 in which a coil 4 is wound around each root portion (bridge portion) 3 of a stator stack 2 having a plurality of pole teeth 1 provided on an inner periphery, and a plurality of poles on an outer periphery And a rotor 10 having two rotor stacks 7 each having teeth 6 arranged along a shaft 8 with a magnet 9 interposed therebetween. When a current flows through the coil 4, the pole teeth 1 of the stator stack 2 and the rotor A torque is generated between the pole teeth 6 of the tack 7 and the rotor 10 to rotate. In this case, each rotor stack 7 is provided with a concave portion 7a having a depth corresponding to approximately one third of the entire thickness at a portion opposite to the side of the magnet 9 here.

The stator stack (stator stack) 2 and the rotor stack (rotor stack) 7 are formed by laminating a plurality of thin substrates cut from a silicon steel plate or the like so that they cannot be separated from each other. You. And, conventionally, at the time of the lamination, an adhesive is applied to the thin substrates,
Starting with the method of joining by welding, etc., the method of caulking with rivets, the method of fitting embossed unevenness, etc.
Various methods have been employed, but since lamination can be easily performed only by mechanical pressing (fitting), recently, a method using embossed concave / convex fitting has been frequently used.

[0004] Conventionally, in the case of the above-mentioned embossed concave-convex fitting, as shown in FIGS. 7 and 8, a thin substrate 11 (FIG. 7) for the stator stack 2 is provided.
A relatively small-diameter round emboss 12 is provided on the bridge portion 3, and a relatively large-diameter round emboss 14 is provided at each of the four corners on both sides of the mounting hole 13, while a thin wall for the rotor stack 7 is provided. With respect to the substrate 15 (FIG. 8), the one corresponding to the concave portion 7a may be a ring-shaped thin substrate 15 ', so that round embosses 16 and corner embosses 17 are alternately provided along the outer periphery. I was In some cases, a square emboss 18 (indicated by a phantom line in FIG. 7) is provided for the thin substrate 11 for the stator stack 2 instead of the round emboss 12.

[0005]

Heretofore, each emboss provided on the thin substrates 11 and 15 has been set to be relatively large in consideration of peel resistance. Specifically, the round emboss 1 of the bridge portion 3 in the thin substrate 11
2 is about 1.3 mm in diameter, the round embossment 14 at the corner is about 2 mm in diameter, and the corner emboss 18 of the same bridge 3 is 1 × 4.
mm, and the round emboss 16 on the thin substrate 15 has a diameter of about 1 mm,
Was set to about 0.6 × 1 mm. For this reason, the embosses 12, 18, 16, and 17 that are arranged particularly close to the pole teeth 1 (FIG. 7) and the pole teeth 6 (FIG. 8) become resistant to the passage of magnetic flux, and are not connected to the magnetic path around them. A difference in magnetic flux density occurs between the magnetic circuits, and the magnetic balance of the entire magnetic circuit is disrupted, and the motor characteristics are adversely affected. As a result, strict demands on motor performance accompanying high performance, miniaturization, and energy saving of OA equipment in recent years have resulted. There was a problem that it was not able to cope sufficiently.

On the other hand, the above-mentioned embosses 12, 14, 1
8 (FIG. 7), 16, 17 (FIG. 8), etc., as shown in FIG.
After the thin substrate 11 or 15 is placed on the
2 is moved downward to partially protrude the thin substrate 11 or 15 into the recess 20. However, in the conventional mold, the misalignment between the recess 20 of the die 21 and the punch 22 is adopted. A considerably large value of 10 μm or more was allowed as the amount δ. For this reason, as shown in FIG.
When laminating 1 or 15, the embossed convex portion A and concave portion B
And the burrs C rise between the thin substrates 11 or 15, and a gap D is formed between them.
The phenomenon that occurred was often occurring. When such a gap D occurs, the magnetic balance of the entire magnetic circuit is lost. In addition, the strength (rigidity) of the stacked stacks 2 and 7 is insufficient, vibration increases, and electric and mechanical noises increase. However, there has been a problem that the durability reliability for electric devices is greatly impaired. Further, it has been found that the galling described above is accompanied by surface buckling, and the peel strength cannot be increased even if the emboss is increased, and there is also a problem that a decrease in strength cannot be avoided from this surface. there were.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a laminated stack which greatly contributes to improving the performance of electric equipment by providing an emboss which does not adversely affect the magnetic balance. Another object of the present invention is to provide a manufacturing method capable of providing such a stacked stack with high accuracy and stability.

[0008]

According to the present invention, there is provided a laminated stack according to the present invention, wherein a plurality of thin-walled substrates are laminated by embossing and embossing with each other. And a round emboss having a diameter of 0.8 mm or less. In the present laminated stack, the embossing provided on the thin substrate is a round embossing having a diameter of 0.8 mm or less, so that the area occupied by the embossing is significantly reduced as compared with the conventional one, and the resistance to the passage of magnetic flux is reduced by that much, and the magnetic field is reduced. The balance is improved. When the laminated stack is for a stator or a rotor, the emboss placed at a position away from the pole teeth does not significantly affect the magnetic balance. Therefore, the round emboss having a diameter of 0.8 mm or less is close to the pole teeth. Only those that are placed.

In order to achieve the above object, a method of manufacturing a laminated stack according to the present invention is characterized in that a thin substrate obtained by punching is processed into a round emboss having a diameter of 0.8 mm or less,
In the method of manufacturing a laminated stack in which a plurality of the thin substrates are laminated while embossing the concave and convex with each other, the amount of misalignment between a die of a forming die and a punch is set to 3 μm or less when the emboss is processed. Features. In the method of manufacturing a laminated stack performed in this way, by setting the amount of misalignment between the die of the forming die for embossing and the punch to 3 μm or less, when embossing is irregularly fitted, a thin substrate is laminated. Galling does not occur in the concave-convex fitting portion, and not only can thin substrates be brought into close contact with each other, but also peeling resistance after lamination is improved.

The present invention also includes an embossing mold used in the above-described method for manufacturing a laminated stack, wherein the mold has an offset between the die and the punch set to 3 μm or less. The present invention further includes an electric device including the above-described laminated stack as a component.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3 show a stacked stack according to one embodiment of the present invention. In addition, this laminated stack is the stator stack 2
And the rotor stack 7 (FIGS. 5 to 8), and their overall structure is the same as that shown in FIGS. 5 to 8 described above. I will attach it.

In the present embodiment, the thin substrate 11 for the stator stack 2 and the thin substrate 15 for the rotor stack 7 are formed by the corner embossments 18 and 17 (FIGS. 7 and 8).
And all have round embosses 12, 13 and 16. In addition, in these thin substrates 11 and 15, the diameter of each round embossment 12, 13 and 16 is set smaller than in the past. Specifically, the round embossment 12 of the bridge portion 3 of the thin substrate 11 is set to have a diameter of 0.8 mm or less, the round embossment 14 of the corner portion is set to a diameter of 1 mm or less, and the round emboss 16 of the thin substrate 15 has a diameter of 0 mm or less. .
It is set to 8mm or less. That is, in the present embodiment, the diameter D (FIG. 1) of the round embosses 12 and 16 close to the pole teeth 1 and 6 is 0.8 mm or less, and the diameters of the conventional round embosses 12 and 16 are each smaller. Compared to 1.3 mm and 1 mm, it is significantly smaller. The height h of the projection of each round embossment 12, 13, 16 is about 70% of the thickness t of the thin substrates 11, 15 (FIG. 1).

The stator stack 2 and the rotor stack 7 are punched from a silicon steel plate or the like in the same manner as in the prior art to obtain the thin substrates 11 and 15.
Then, the round embosses 12 and 16 having a diameter of 0.8 mm or less or the round embosses 14 having a diameter of 1 mm or less are processed.
It is manufactured by laminating 2, 13, and 16 while fitting the concave and convex.

The above-mentioned round embosses 12, 13, 1
6, the thin substrate 11 or 15 is placed on a die 21 having a molding recess 20 on the upper surface, and the punch 22 is moved downward to process the thin substrate 1 as in the conventional case (FIG. 9).
A method of partially projecting 1 or 15 into the concave portion 20 is adopted. Here, as a forming die, the amount of misalignment δ between the concave portion 20 of the die 21 and the punch 22 is 3 μm.
m or less. That is,
While the misalignment amount δ of the conventional mold was 10 μm or more, the misalignment amount δ of the mold in the present embodiment was
Is significantly smaller.

In the stator stack 2 or the rotor stack 7 constructed and manufactured as described above, the amount of misalignment between the molding die 21 and the punch 22 is set to 3 μm or less, and embossing is performed. As shown in FIG. 1, when the thin substrates 11 or 15 are laminated by making the round embosses 12, 16 (or 13) unevenly fit, no galling occurs on the uneven fitting portion, and the thin substrate 11 or 15 is not formed.
Can be laminated in close contact with each other. Therefore, the obtained stator stack 2 or rotor stack 7 has not only improved peel strength and rigidity, but also reduced vibration and reduced electrical and mechanical noise.

Further, since the round embossments 12 and 16 arranged particularly close to the pole teeth 1 and 6 are set to a small value having a diameter of 1 mm or less, the emboss has a large resistance to magnetic flux passage. Thus, the stator stack 2 and the rotor stack 7 having good magnetic balance can be stably obtained. Therefore, the stepping motor incorporating the stator stack 2 and the rotor stack 7 not only increases the torque, but also reduces the torque ripple, and furthermore, the rotational accuracy is improved and the performance is remarkably improved.

[0017]

As described above, according to the laminated stack according to the present invention, the round embosses having a small diameter are fitted into the concave and convex, so that the magnetic balance is improved, and the performance and the size of the electric equipment are improved. This greatly contributes to energy saving, and the use value of electric equipment incorporating these is remarkably improved. Further, according to the method for manufacturing a laminated stack and the mold according to the present invention, the above-described laminated stack can be obtained with high accuracy and stability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure of a stacked stack according to one embodiment of the present invention.

FIG. 2 is a plan view showing a structure of a stator stack constituting the stepping motor.

FIG. 3 is a plan view showing a structure of a rotor stack constituting the stepping motor.

FIG. 4 is a plan view showing the structure of a laminated stepping motor.

FIG. 5 is a perspective view showing a general structure of a stator stack constituting the stepping motor shown in FIG.

6 is a perspective view showing a structure of a rotor constituting the stepping motor shown in FIG.

FIG. 7 is a plan view showing the structure of a conventional stator stack.

FIG. 8 is a plan view showing a structure of a conventional rotor stack.

FIG. 9 is a cross-sectional view showing a molding die for embossing a thin substrate and its use mode.

FIG. 10 is a cross-sectional view showing a state of occurrence of a defect in a conventional laminating step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pole tooth 2 Stator stack (laminated stack for stator) 4 Coil 5 Stator 6 Pole tooth 7 Rotor stack (laminated stack for rotor) 10 Rotor 12, 14 Round emboss of stator stack 16 Round emboss of rotor stack

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H002 AA01 AB01 AC08 AE02 5H615 AA01 BB01 BB08 BB14 PP01 PP02 PP06 SS05 SS19 TT04

Claims (5)

[Claims] 1. A laminated stack in which a plurality of thin substrates are laminated by embossing and embossing with respect to each other, wherein the emboss is a round emboss having a diameter of 0.8 mm or less. 2. A stator or rotor laminated stack in which a plurality of thin substrates having polar teeth arranged in a circumferential direction are laminated by embossing and concavely fitting each other, and are arranged at least in proximity to the polar teeth. The emboss to be used is
A laminated stack having a round embossing of 8 mm or less. 3. A thin substrate obtained by punching has a diameter of 0.3 mm.
In a method for manufacturing a laminated stack in which a plurality of thin-walled substrates are laminated while embossing the concave and convex with each other after processing a round embossment of 8 mm or less, when the embossing is performed, the center of a die and a punch of a forming die is used. A method for manufacturing a laminated stack, wherein a shift amount is set to 3 μm or less. 4. A molding die for embossing, wherein an amount of misalignment between a die and a punch is set to 3 μm or less. 5. An electric device comprising the laminated stack according to claim 1 as a constituent element.