JP2020092139A - Stator core, motor, and manufacturing method of stator core - Google Patents

Abstract

To provide a stator core capable of achieving a high precision inner diameter while improving the productivity, a motor, and a manufacturing method of a stator core.SOLUTION: A stator core 101 is formed of a lamination of thin band 1 of nanocrystalline soft magnetic material, in which the inner diameter dimensional accuracy is ±30 μm or less, and the inner diameter roundness is 30 μm or less.SELECTED DRAWING: Figure 5A

Description

The present disclosure relates to a stator core, a motor, and a method for manufacturing a stator core using a ribbon of a nanocrystalline soft magnetic material.

Conventionally, an electromagnetic steel plate is generally used for a stator core (stator core) included in a stator (stator) of a motor. However, in order to achieve higher efficiency, higher output, energy saving, downsizing, and the like, there is known a stator core using a ribbon having an amorphous or nanocrystalline grain (for example, Patent Document 1). 1).

Pressing can be used as a method of manufacturing a stator core using a ribbon of a nanocrystalline soft magnetic material. However, in press working, the precision of the press machine is required. Further, since the thin ribbon of the nanocrystalline soft magnetic material is about 1/10 or less (for example, 0.03 mm) of the thickness of the electromagnetic steel sheet (for example, 0.35 mm), it is necessary to set the mold clearance to several μm. There is. Therefore, it is very difficult to manufacture a die used for press working.

As a method other than the press working, a working method of an amorphous laminated core is known (for example, refer to Patent Document 2). In this method, a laminated body of nanocrystalline soft magnetic material thin plates coated with an insulating resin is wire-discharge machined to be cut into a predetermined core shape, and then the cut surface is etched.

JP-A-6-145917 JP, 2008-198898, A

The inner diameter of the stator core is important, but the amorphous laminated core processing method disclosed in Patent Document 2 has the following problems.

In order to finish the inner diameter dimension with high precision by wire electric discharge machining, first, rough machining is required to make the inner diameter dimension smaller than the final inner diameter dimension. After that, it takes time to finish the final inner diameter dimension using a minute current. Therefore, the method of Patent Document 2 requires an enormous amount of processing time, resulting in low productivity.

An object of one aspect of the present disclosure is to provide a stator core, a motor, and a method of manufacturing a stator core, which can secure a highly accurate inner diameter dimension and improve productivity.

A stator core according to an aspect of the present disclosure is a stator core in which thin ribbons of a nanocrystalline soft magnetic material are laminated, the inner diameter dimensional accuracy of the inner diameter portion is ±30 μm or less, and the inner diameter circularity is 30 μm or less. is there.

A motor according to one aspect of the present disclosure, a stator core according to one aspect of the present disclosure, a reinforcing plate provided by sandwiching the upper and lower surfaces of the stator core, a fastening member that fixes the stator core and the reinforcing plate, and the stator core. And a rotor provided in the inner diameter part of the.
motor.

A stator core manufacturing method according to an aspect of the present disclosure is a stator core manufacturing method including a plurality of processing steps of punching a ribbon of a nanocrystalline soft magnetic material, and is capable of executing each of the plurality of processing steps. , Using a plurality of dies provided independently of each other, a pressing pressure required for each of the processing steps is applied to the ribbon.

According to the present disclosure, it is possible to secure a highly accurate inner diameter dimension and improve productivity.

The top view which shows the processing process of the core sheet which concerns on embodiment of this indication in order. A side view of a mold used for a processing step of a core sheet concerning an embodiment of the present disclosure. Top view of a core sheet formed by punching using a conventional die Side view of conventional mold Top view of a stator core according to an embodiment of the present disclosure Side view of a stator core according to an embodiment of the present disclosure

Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings. In addition, the same reference numerals are given to common constituent elements in each drawing, and the description thereof will be appropriately omitted.

<Manufacturing method of core sheet>
A core sheet manufacturing method (an example of a stator core manufacturing method) according to an embodiment of the present disclosure will be described with reference to FIG. 1. FIG. 1 is a top view that sequentially shows the processing steps of the core sheet according to the embodiment of the present disclosure.

Here, as an example, a thin strip 1 (hereinafter, also simply referred to as “thin strip 1”) of a nanocrystalline soft magnetic material having a thickness (hereinafter, also referred to as a plate thickness) of 30 μm is punched to form one sheet. The process of manufacturing the core sheet will be described.

As a method of manufacturing the ribbon 1 of the nanocrystalline soft magnetic material, for example, a method is known in which the melted magnetic material is dropped onto a cooling high-speed rotating roller and the surface thereof is instantly cooled. However, with this method, it is difficult to control the falling rate, cooling rate, cooling strain, etc. of the molten magnetic material. Therefore, unlike the magnetic steel sheet, which is a rolled material, the manufactured ribbon 1 has a variation in thickness.

On the other hand, the manufactured ribbon 1 has a high magnetic permeability and an extremely low iron loss as compared with the magnetic steel sheet, and is therefore a highly superior material.

The following can be used as the nanocrystalline soft magnetic material. For example, the nanocrystalline soft magnetic material contains 93% to 94% by mass of iron, and has a high iron concentration type including an amorphous magnetic layer around α-iron (α-Fe) grains of about 10 nm. Ultra-low-loss nanocrystalline soft magnetic material.

The amorphous magnetic layer is composed of general elements such as silicon (Si), boron (B), phosphorus (P), and copper (Cu), and has a composition containing no rare metal system. Therefore, the amorphous magnetic layer is an ideal material with a small risk due to the high price of the material. In addition, the amorphous magnetic layer can achieve high magnetic flux density with low iron loss. Therefore, by using a high iron concentration type ultra-low loss nanocrystalline soft magnetic material for applications requiring a strong magnetic field (for example, a large current transformer used in a power grid, a motor, etc.), iron loss can be reduced. A major contribution is expected in terms of energy saving.

Hereinafter, the processing steps 1 to 5 shown in FIG. 1 will be described. Here, the case where the number of steps is 5 will be described as an example, but the number of steps may be other than 5 depending on the product and punchability.

First, in the processing step 1, a plurality of guide holes 2 are punched out. The guide hole 2 is a hole that functions for positioning after the machining process 2. The guide holes 2 are formed so as to be separated from each other in the width direction (vertical direction of the drawing) and the longitudinal direction (horizontal direction of the drawing) of the thin ribbon 1 of the nanocrystalline soft magnetic material.

Next, in the processing step 2, a plurality of slot holes 3 are punched and formed. For example, as shown in FIG. 1, nine slot holes 3 are formed in a circular shape. A winding (not shown) is provided in each slot hole 3. The winding may be wound in the width direction (see FIG. 5A described later) of the tooth portion, which is a portion between the adjacent slot holes 3. The number and shape of the slot holes 3 are not limited to those shown in FIG.

Next, in the processing step 3, a plurality of fastening holes 4 are punched and formed. For example, as shown in FIG. 1, three fastening holes 4 are formed around the slot hole 3. Fastening members (for example, bolts) are inserted into the fastening holes 4 during final assembly of the stator core (see FIGS. 5A and 5B described later).

Next, in the processing step 4, the inner diameter hole 5 is punched out. The inner diameter hole 5 is an important element that determines the air gap between the outer diameter of the rotor and the inner diameter of the stator, which determines the efficiency of the motor. By punching the inner diameter hole 5 here, a circular opening (hereinafter referred to as an inner diameter portion; see FIG. 5A to be described later) surrounded by the end faces of the tooth portions when viewed from directly above is formed.

Next, in the processing step 5, the outer diameter portion 6 (in other words, the circumferential portion) is punched. Although the outer diameter portion 6 has a circular shape in FIG. 1 as an example, it may have another shape (for example, a quadrangle or the like).

Through the above-described processing steps 1 to 5, one core sheet is manufactured.

By stacking a plurality of core sheets manufactured in this way, a stator core (see FIGS. 5A and 5B described later) can be manufactured.

<Mold configuration>
The progressive die 70 used in the processing steps 1 to 5 will be described with reference to FIG. FIG. 2 is a side view of the mold 70.

As shown in FIG. 2, the mold 70 has molds 10, 20, 30, 40, 50 capable of performing the processing steps 1 to 5, respectively. The molds 10, 20, 30, 40, 50 are provided side by side independently of each other.

The mold 10 is a mold for punching out the guide hole 2 (see FIG. 1). The mold 20 is a mold for punching out a plurality of slot holes 3 (see FIG. 1). The mold 30 is a mold for punching out a plurality of fastening holes 4 (see FIG. 1). The die 40 is a die for punching and forming the inner diameter hole 5 (see FIG. 1). The die 50 is a die for punching and forming the outer diameter portion 6 (see FIG. 1).

The upper mold of the mold 10, 20, 30, 40, 50 will be described. As shown in FIG. 2, the dies 10, 20, 30, 40, 50 include punches 11, 21, 31, 41, 51, and punch plates 13, 23, 33, 43, which serve to hold them, respectively. 53, the plate pressing plates 14, 24, 34, 44, 54, and the upper die sets 12, 22, 32, 42, 52. The upper die sets 12, 22, 32, 42, 52 are held by the upper die set holder 60. The upper die set holder 60 is fixed to a slide 80 of a press machine (not shown).

The lower molds of the molds 10, 20, 30, 40, 50 will be described. As shown in FIG. 2, the dies 10, 20, 30, 40, 50 include dies 15, 25, 35, 45, 55, and die plates 17, 27, 37, 47, which serve to hold them, respectively. 57 and lower die sets 16, 26, 36, 46, 56. The lower die sets 16, 26, 36, 46, 56 are held by the lower die set holder 62. The lower die set holder 62 is fixed to the bolster 81 of the press machine.

As described above, the ribbon 1 of the nanocrystalline soft magnetic material has a variation in thickness unlike the magnetic steel sheet which is a rolled material. For example, as shown in FIG. 2, the plate thickness of the ribbon 1 is non-uniform and is in a wavy state (a wavy state).

Specifically, when the median thickness of the thin strips 1 is 30 μm, the thickness deviation of the thin strips 1 is about 5 μm, so that the thickness range of the thin strips 1 is 25 μm to 35 μm.

In order to sequentially punch the thin strips 1 whose plate thicknesses greatly vary in each processing step, the mold 70 is a mold 10, 20, 30, 40, 50 capable of executing each of the processing steps 1 to 5. Is equipped independently. In each of the dies 10, 20, 30, 40, 50, the strip 1 is reliably pressed by the plate pressing plates 14, 24, 34, 44, 54 and the die plates 17, 27, 37, 47, 57. It is possible to add a pressing pressure required for each processing step to the ribbon 1 in order to secure punching accuracy. Therefore, it is possible to realize highly accurate punching even with a minute clearance, and it is possible to absorb variations in the plate thickness of the ribbon 1.

<Conventional mold>
A case where a conventional die is used to perform punching on the thin strip 1 having a variation in plate thickness will be described with reference to FIG. FIG. 3 is a top view of a core sheet formed by performing the above-described processing steps 1 to 5 using a conventional mold.

A perfect circular shape 201 indicated by a chain double-dashed line in FIG. 3 is a shape of a cutting edge (that is, a punch and a die) of a conventional die. However, the actually punched inner diameter hole shape 200 deviates from the perfect circular shape 201 and has a distorted shape.

The conventional mold described above will be described with reference to FIG. FIG. 4 is a side view of the conventional mold 370. 4, the same components as those in FIG. 2 are designated by the same reference numerals.

The mold 370 shown in FIG. 4 is different from the mold 70 shown in FIG. 2 in that it has a mold 310 capable of performing the processing steps 1 to 3 and a mold 320 capable of performing the processing steps 4 to 5. different. That is, the mold 70 has a structure in which the molds 10, 20, 30, 40, and 50 corresponding to each of the processing steps 1 to 5 are independently provided, whereas the mold 370 has such a structure. It is not a simple configuration.

The upper mold of the mold 310 will be described. As shown in FIG. 4, the die 310 includes punches 11, 21, and 31, a punch plate 313 that plays a role of holding them, a plate pressing plate 314, and an upper die set 312. The upper die set 312 is held by the upper die set holder 60.

The lower mold of the mold 310 will be described. As shown in FIG. 4, the mold 310 includes the dies 15, 25, 35, a die plate 317 that holds them, and a lower die set 316. The lower die set 316 is held by the lower die set holder 62.

The upper mold of the mold 320 will be described. As shown in FIG. 4, the die 320 includes punches 41 and 51, a punch plate 323 that holds the punches 41, 51, a plate pressing plate 324, and an upper die set 322. The upper die set 322 is held by the upper die set holder 60.

The lower mold of the mold 320 will be described. As shown in FIG. 4, the die 320 has dies 45 and 55, a die plate 327 that holds them, and a lower die set 326. The lower die set 326 is held by the lower die set holder 62.

As described above, the plate pressing plate 314 and the die plate 317, and the plate pressing plate 324 and the die plate 327 have configurations corresponding to two or more processing steps, respectively.

Here, as an example, since it is assumed that the outer diameter of the stator is relatively large (for example, about φ110 mm), each of the plate pressing plate and the die plate is divided into two, but depending on the outer diameter of the stator, The plate pressing plate and the die plate may not be divided.

In the die 370 having the above-described structure, when the thin ribbon 1 of the nanocrystalline soft magnetic material has a wavy plate thickness as shown in FIG. 4, the pressing pressure required for each processing step to secure the punching accuracy is , Is not added to the ribbon 1.

That is, when the plate pressing plates 314 and 324 are tilted, when the thin strip 1 is punched by the punches 11, 21, 31, 41 and 51, the phenomenon of drawing into the dies 15, 25, 35, 45 and 55 may occur. It may occur, or the minute clearance for punching may change, and residual distortion may occur in the peripheral portion of the punched portion. Therefore, in the stator core in which the core sheets manufactured by using the mold 370 are laminated, the required inner diameter dimensional accuracy and inner diameter roundness of the inner diameter portion cannot be secured. The stator core had a maximum inner diameter dimensional accuracy of 80 μm (inner diameter roundness of 50 μm).

<Effect>
In contrast to the above-mentioned mold 370, in the mold 70 of the present embodiment shown in FIG. 2, the molds 10, 20, 30, 40, 50 corresponding to the respective processing steps 1 to 5 are independently provided. ing. That is, the plate pressing plates 14, 24, 34, 44, 54 and the die plates 17, 27, 37, 47, 57 are independently provided. Therefore, for example, even in the case of the thin strip 1 in which the variation of the plate thickness is ±5 μm or less and the plate thickness deviation in the range of one stator is 5 μm or less, it is necessary in each of the processing steps 1 to 5. Pressing pressure can be applied reliably, and highly accurate punching can be performed.

Therefore, in punching using the die 70 of the present embodiment, the inner diameter is superior to other machining methods (for example, wire electric discharge machining or the machining method using the die 370 shown in FIG. 4). It is possible to obtain a core sheet having dimensional accuracy and circularity of inner diameter. By stacking the core sheets, a stator core having excellent inner diameter dimensional accuracy (±30 μm or less, preferably ±15 μm or less) and inner diameter roundness (30 μm or less, preferably 10 μm or less) of the inner diameter portion 106 is laminated. Can be obtained.

In the present embodiment, the case of manufacturing the stator core for the inner rotor type motor has been described as an example, but the mold 70 can be used even when manufacturing the stator core for the outer type motor. In that case, a stator core having an excellent outer diameter dimension (for example, ±15 μm or less) and an inner diameter roundness (for example, 10 μm or less) can be obtained.

Further, in the present embodiment, the case where the plate thickness range of the nanocrystalline soft magnetic material ribbon 1 is 25 μm to 35 μm has been described as an example, but the plate thickness range of the ribbon 1 is not limited to this. However, it may be, for example, in the range of 20 to 40 μm. Even in that case, the required inner diameter dimension and inner diameter roundness can be obtained.

<Stator core>
The stator core 101 of this embodiment will be described with reference to FIGS. 5A and 5B. FIG. 5A is a top view of the stator core 101. Further, FIG. 5B is a side view of the stator core 101.

As shown in FIG. 5B, the stator core 101 is formed by stacking a plurality of core sheets. The core sheet here is manufactured by performing the processing steps 1 to 5 shown in FIG. 1 using the mold 70 shown in FIG.

Further, as shown in FIG. 5A, the stator core 101 includes a plurality of teeth portions 105 and an inner diameter portion 106. A winding (not shown) is wound around each tooth portion 105.

In addition, as shown in FIG. 5B, reinforcing plates 102 are stacked above and below the stator core 101. In other words, the two reinforcing plates 102 are provided so as to sandwich the stator core 101 from above and below. Since the stator core 101 has thin and brittle layers laminated by heat treatment, the reinforcing plate 102 protects the stator core 101 from the vertical direction.

The reinforcing plate 102 is preferably made of a material that has higher rigidity and is stronger than the stator core 101. Examples of such a material include, but are not limited to, electromagnetic steel sheets, and stainless steel sheet materials and the like may be used.

The stator core 101 and the reinforcing plate 102 are fixed to the fastening block 104 by fastening members 103 (for example, bolts) that penetrate the stator core 101 and the reinforcing plate 102 in the stacking direction (vertical direction in the drawing).

The configuration including the stator core 101 having the windings and the reinforcing plate can be generally called a stator. This stator is used, for example, in a motor. In that case, a rotor (not shown) is provided inside the inner diameter portion 106 of the stator core 101.

The inner diameter of the stator core 101 is a relatively large diameter of about 60 mm, but in the stator core 101, the inner diameter dimensional accuracy is ±30 μm or less (preferably ±15 μm or less) with respect to the inner diameter, and the inner diameter circularity is It becomes 30 μm or less (preferably 10 μm or less). That is, in the stator core 101, excellent inner diameter dimensional accuracy and inner diameter roundness can be ensured.

If the inner diameter of the stator core is smaller than φ60 mm, the inner diameter dimensional accuracy and inner diameter roundness are further improved.

As described above, according to the present embodiment, the die 70 capable of independently applying pressure in each step when punching the thin ribbon 1 of the nanocrystalline soft magnetic material having an uneven thickness is provided. To use. Therefore, since the pressing pressure required for each processing step can be applied to the ribbon 1, it is possible to realize highly accurate punching and to absorb the variation in the plate thickness of the ribbon 1. Therefore, in the stator core 101, a highly accurate inner diameter dimension can be secured. Further, since a huge processing time is not required, the productivity of the stator core 101 can be improved. Further, the motor manufactured by using the stator core 101 is stable with high quality without lowering the efficiency of the motor. In addition, it is possible to improve the productivity of the motor and reduce the cost.

Note that the present disclosure is not limited to the above description of the embodiments, and various modifications can be made without departing from the spirit of the present disclosure.

INDUSTRIAL APPLICABILITY The stator core, the motor, and the method of manufacturing the stator core according to the present disclosure can be applied to the use of magnetically applied electronic components such as a transformer in addition to the motor.

1 Thin Band of Nanocrystalline Soft Magnetic Material 2 Guide Hole 3 Slot Hole 4 Fastening Hole 5 Inner Diameter Hole 6 Outer Diameter Part 10, 20, 30, 40, 50 Mold 11, 21, 31, 41, 51 Punch 12, 22, 32, 42, 52 Upper die set 13, 23, 33, 43, 53 Punch plate 14, 24, 34, 44, 54 Plate holding plate 15, 25, 35, 45, 55 Die 16, 26, 36, 46, 56 Lower die set 17, 27, 37, 47, 57 Die plate 60 Upper die set holder 61 Lower spacer holder 62 Lower die set holder 70 Mold 80 Slide of press machine 81 Bolster of press machine 101 Stator core 102 Reinforcing plate 103 Fastening member 104 Fastening block 105 Teeth portion 106 Inner diameter portion 200 Inner diameter hole shape 201 True circle shape 310, 320 Mold 312, 322 Upper die set 313, 323 Punch plate 314, 324 Plate holding plate 316, 326 Lower die set 317, 327 Die plate 360 Upper die set holder 370 Mold

Claims (6)

A stator core in which ribbons of nanocrystalline soft magnetic material are laminated,
The inner diameter dimensional accuracy of the inner diameter portion is ±30 μm or less, and the inner diameter roundness is 30 μm or less,
Stator core. The inner diameter dimensional accuracy is ±15 μm or less, and the inner diameter roundness is 10 μm or less.
The stator core according to claim 1. A stator core according to claim 1 or 2,
A reinforcing plate provided by sandwiching the upper and lower surfaces of the stator core;
A fastening member for fixing the stator core and the reinforcing plate,
A rotor provided in an inner diameter portion of the stator core,
motor. A method of manufacturing a stator core including a plurality of processing steps for punching a ribbon of a nanocrystalline soft magnetic material,
Each of the plurality of processing steps can be performed, and a plurality of molds provided independently of each other are used to apply a pressing pressure required for each of the processing steps to the ribbon.
Manufacturing method of stator core. The plurality of molds are arranged in parallel in the order of the processing steps,
The method for manufacturing a stator core according to claim 4. The plurality of processing steps,
A step of forming positioning guide holes in the ribbon,
Forming a slot hole for winding in the ribbon,
Forming a fastening hole into which the fastening member is inserted, in the ribbon;
A step of forming an inner diameter hole surrounded by the end surface of the tooth portion in the ribbon,
Punching the outer diameter portion to form a core sheet,
The method for manufacturing a stator core according to claim 4 or 5.

Images