WO2024116811A1

WO2024116811A1 - Amorphous alloy piece manufacturing method, laminated iron core manufacturing method, and laminated iron core

Info

Publication number: WO2024116811A1
Application number: PCT/JP2023/040839
Authority: WO
Inventors: 改大橋
Original assignee: 株式会社アイシン
Priority date: 2022-11-30
Filing date: 2023-11-14
Publication date: 2024-06-06

Abstract

Disclosed is an amorphous alloy piece manufacturing method including: a step for preparing a ribbon of an amorphous alloy; a step for radiating a laser such that a plurality of laser irradiated portions are formed in an adjacent manner with non-irradiated portions interposed therebetween, along a boundary of a target region of the ribbon; and a cutting or cleaving step for cutting or cleaving the ribbon along the boundary. This makes it possible to improve machining characteristics when cutting the ribbon along the boundary of the target region, while reducing an amount of input heat.

Description

Manufacturing method of amorphous alloy flakes, manufacturing method of laminated iron core, and laminated iron core

This disclosure relates to a method for manufacturing amorphous alloy flakes, a method for manufacturing laminated iron cores, and laminated iron cores.

In consideration of the difficulty of processing amorphous alloy ribbons (difficulty in processing with respect to punching), a technique is known in which a laser is continuously irradiated onto the amorphous alloy ribbon in advance to form a continuous outline of the laser irradiated areas (recesses), and then punching is performed along the continuous outline.

JP 2022-40071 A

However, in the conventional techniques described above, the amount of heat input during laser irradiation tends to be large because the laser irradiated area (recess) forms a continuous contour line, which can easily lead to problems such as changes in characteristics associated with crystallization in the amorphous alloy ribbon and thermal runaway caused by heat generation due to crystallization.

In one aspect, the present disclosure aims to reduce the amount of heat input while improving workability when cutting along the boundary of a target region in a thin strip.

In one aspect, a method for producing a ribbon of an amorphous alloy includes the steps of:
irradiating the ribbon with a laser so that a plurality of laser irradiated portions are formed adjacent to each other via non-irradiated portions along a boundary of a target region in the ribbon;
and a cutting or cleaving step of cutting or cleaving the ribbon along the boundary.

In one aspect, the present disclosure makes it possible to reduce the amount of heat input while improving workability when cutting along the boundary of a target region in a thin strip.

1 is a schematic flow chart showing a method for manufacturing a laminated iron core to which the method for manufacturing amorphous alloy flakes according to the present embodiment is applied. FIG. 2 is an explanatory diagram of the present manufacturing method, and is a schematic diagram showing a manufacturing apparatus and a workpiece for implementing the present manufacturing method. 1 is a plan view of a portion of a workpiece on which discontinuous laser irradiated portions are formed. FIG. FIG. 4 is an enlarged view of a portion Q1 in FIG. 3 . 1 is a graph showing an example of characteristics (heat generation curve) of an amorphous metal ribbon. FIG. 2 is a plan view of a laminated core in the form of a stator core. 7 is a schematic diagram showing a cut surface of the inner radial direction of three amorphous alloy pieces as viewed from the arrow V6 in FIG. 6. FIG.

Each embodiment will be described in detail below with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting. Also, shapes in the drawings may be partially exaggerated for the sake of explanation.

FIG. 1 is a schematic flow chart showing a method for manufacturing a laminated core 30 to which the method for manufacturing an amorphous alloy flake 80 according to this embodiment is applied. FIG. 2 is an explanatory diagram of this manufacturing method, and is a schematic diagram showing a manufacturing apparatus 100 and a workpiece W for implementing this manufacturing method.

This manufacturing method includes a preparation step (step S1) of preparing a ribbon of an amorphous alloy (hereinafter also referred to as "amorphous metal ribbon"). The concept of amorphous metal ribbon includes, for example, a ribbon of a nanocrystalline alloy. A nanocrystalline alloy is an alloy in which nano-order α-Fe crystals (nanocrystals) are densely dispersed in an amorphous parent phase as a crystal structure. Such nanocrystalline alloys can achieve high magnetic flux density due to their high iron content, and can maintain low iron loss even in the magnetic flux density range. Therefore, amorphous metal ribbons are suitable as materials for stator cores and rotor cores of rotating electrical machines.

In this preparation process, for example, the strip-shaped amorphous metal ribbon may be prepared in a state wound around a roll 40 (see FIG. 2). In this case, the strip-shaped amorphous metal ribbon winding body W0 wound from the roll 40 may be unwound (see arrow R2 in FIG. 2) and supplied to the next process as the amorphous metal ribbon workpiece W.

The manufacturing method then includes a laser irradiation step (step S2) in which the amorphous metal ribbon is irradiated with a laser. The laser used in the laser irradiation step is arbitrary, but is preferably an ultrashort pulse laser. The ultrashort pulse laser has a pulse width of, for example, several femtoseconds to several picoseconds, and is advantageous in that it allows for highly accurate micromachining and reduces thermal damage to the workpiece W. FIG. 2 shows a schematic diagram of a laser irradiation device 50. In FIG. 2, the laser irradiation device 50 is arranged so that it acts first on the workpiece W unwound from the roll 40, but a pretreatment device may be provided upstream of the laser irradiation device 50. For example, the amorphous metal ribbon may be subjected to a preliminary heat treatment at the time of preparation in the above-mentioned preparation step, or may be subjected to a preliminary heat treatment upstream of the laser irradiation device 50. In this case, the preliminary heat treatment may be performed under heating conditions that enhance the magnetic properties.

Here, when the amorphous metal ribbon of the workpiece W is irradiated with a laser, a recess is formed in the amorphous metal ribbon. Hereinafter, such a recess is also referred to as a laser irradiated portion 70. In this manufacturing method, the laser irradiation process forms a plurality of laser irradiated portions 70 in a manner in which the respective laser irradiated portions 70 are spaced apart from one another (i.e., the laser irradiated portions 70 are scattered). That is, in this manufacturing method, the laser irradiation process does not form the laser irradiated portions continuously (seamlessly), but forms the plurality of laser irradiated portions 70 in a discontinuous manner in which they are separated from one another. Hereinafter, such a method of forming a laser irradiated portion is also referred to as a method of forming a discontinuous type laser irradiated portion 70. On the other hand, a method of forming a plurality of laser irradiated portions continuously (seamlessly) from one another is also referred to as a method of forming a continuous type laser irradiated portion.

Here, a method for forming discontinuous laser irradiation portion 70 will be described with reference to Figures 3 and 4. Here, a method for forming discontinuous laser irradiation portion 70 for forming a stator core for a rotating electric machine will be described, but it can also be applied to forming a stator core for a rotating electric machine or other laminated iron cores.

FIG. 3 is a plan view of a portion of the workpiece W in which a discontinuous laser irradiation portion 70 is formed, and FIG. 4 is an enlarged view of portion Q1 in FIG. 3.

In this manufacturing method, as shown in FIG. 3, discontinuous laser irradiation portion 70 is formed along the boundary of the stator core region for forming the stator core (the outline of the punched shape). Specifically, discontinuous laser irradiation portion 70 is formed along cutting target portion 320 that defines the inner peripheral edge of the stator core, cutting target portion 322 that defines the slots of the stator core, and cutting target portion 328 that defines the outer peripheral edge of the stator core.

The cutting target portions 320, 322, and 328 may be formed in the same manner (various parameters a, b, c, d and depth h in FIG. 4, etc.), or may be formed in different manners according to their respective characteristics.

For example, the cutting target portion 328 may be formed in such a manner that the width a, length b, gap c, and pitch d of the laser irradiated portion 70 are controlled, as shown in FIG. 4. In this case, the portion corresponding to the gap c is not irradiated with the laser, and is hereinafter referred to as the "non-irradiated portion 72." The depth h (see FIG. 7) of the laser irradiated portion 70 may also be controlled. The various parameters a, b, c, d, and depth h may be adapted to achieve an optimal balance between reducing the amount of heat input and improving punchability (processability) during press processing, which will be described later.

In addition, in this manufacturing method, the depth h of the laser irradiated portion 70 is arbitrary, but since it has a non-irradiated portion 72, it may be set deep enough to exceed 70% of the thickness of the amorphous metal ribbon, for example, it may be 100%. When it is 100%, the laser irradiated portion 70 is in the form of a through hole rather than a recess.

In this manufacturing method, the ratio (=Σc) of the total length (=Σc) of the non-irradiated portion 72 in the portion to be cut 328 (similarly for the other portions to be cut 320, 322) to the total length (=Σb) of the laser-irradiated portion 70 in the portion to be cut 328 is preferably 1/10 or more, more preferably 1/2 or more, and most preferably 1 or more. In this case, the amount of heat input can be effectively reduced while maintaining relatively good punchability (processability) during press processing. This effect will be described in detail later.

Returning to FIG. 1, the manufacturing method then includes a press processing step (step S3) (an example of a cutting or breaking step) in which each cutting target portion 320, 322, 328 in the amorphous metal ribbon workpiece W is cut by a press machine 60. Note that each cutting target portion 320, 322, 328 may be cut simultaneously, or may be cut separately using a progressive die. FIG. 2 shows a schematic of the press machine 60 downstream of the laser irradiation device 50. Note that in the progressive type, multiple press machines 60 may be arranged in succession.

Next, the manufacturing method includes a lamination process (step S4) in which multiple amorphous alloy pieces 80 cut by press working are laminated to form the laminated core 30. Note that the lamination process may be achieved, for example, by bonding the amorphous alloy pieces 80 together with an adhesive or the like.

As is generally known, amorphous metal ribbons have excellent magnetic properties (high magnetic flux density and low iron loss) and corrosion resistance, but are also difficult to process. Therefore, when cutting (punching) amorphous metal ribbons using a press machine 60 without a laser irradiation unit 70, the durability of the punch and die of the press machine 60 decreases.

In this regard, according to the present manufacturing method, as described above, the cutting target portions 320, 322, 328 pass through a plurality of laser irradiation portions 70. As described above, the plurality of laser irradiation portions 70 are in the form of recesses, and therefore are locations that are easy to cut with the press machine 60. Therefore, according to the present manufacturing method, by forming a plurality of laser irradiation portions 70 in the cutting target portions 320, 322, 328, the processability (processability related to press processing) of the amorphous metal ribbon can be improved.

Here, if emphasis is placed solely on the aspect of improving the workability in press working, it is desirable that the proportion of the laser irradiated portion 70 in the portion to be cut 320 (the same applies to the other portions to be cut 322, 328, and so forth) be as large as possible. In other words, if emphasis is placed solely on the aspect of improving the workability in press working, ultimately, the continuous type laser irradiated portion described above is desirable, and the proportion of the laser irradiated portion 70 in the portion to be cut 320 is 100%.

However, in the case of a continuous laser irradiation section, as mentioned above in the section "Problems to be solved by the invention," the amount of heat input tends to be large, and problems can easily arise in the characteristics of the amorphous metal ribbon as it crystallizes, as well as thermal runaway caused by heat generated by crystallization.

Figure 5 is a graph showing an example of the characteristics (heat generation curve) of an amorphous metal ribbon, with the horizontal axis representing temperature and the vertical axis representing heat generation. Note that the vertical axis indicates that the heat generation increases as the heat generation curve moves downward. Figure 5 shows the characteristics of an Fe-B-Si-P-C-based amorphous alloy, but the characteristics of amorphous alloys of other systems are essentially the same.

As shown in FIG. 5, the heat generation curve for the amorphous metal ribbon has two major peaks p1 and p2, and the first peak p1 is a peak associated with nanocrystallization. Note that a preliminary heat treatment before the above-mentioned laser irradiation process (step S2) may be performed to achieve such nanocrystallization. The second peak p2 represents the heat generation due to crystallization associated with the precipitation of Fe-B and the like. When such a second peak p2 occurs, a change in characteristics occurs in the amorphous metal ribbon due to crystallization, which may impair the excellent magnetic characteristics (high magnetic flux density and low iron loss) as described above. There is also a risk of thermal runaway.

In contrast, according to this embodiment, as described above, the laser irradiation process is performed so that multiple cutting target portions 320 are formed adjacent to one cutting target portion 320 via non-irradiated portions 72, so the amount of heat input to one cutting target portion 320 can be reduced. That is, according to this embodiment, by including non-irradiated portions 72 that can reduce the amount of heat input in the cutting target portion 320, the amount of heat input to one cutting target portion 320 can be reduced. This effectively reduces the possibility of the temperature of the workpiece W rising to a temperature range where the second peak p2 occurs. As a result, the above-mentioned inconveniences that occur in the case of a continuous laser irradiation portion can be reduced.

Next, the laminated core 30 of this embodiment will be described with reference to Figures 6 and 7. Figure 6 is a plan view of the laminated core 30 in the form of a stator core, and Figure 7 is a schematic diagram showing a portion (the radially inner cut surface of three amorphous alloy pieces 80, which corresponds to the cut surface to be cut 320) from the view of arrow V6 in Figure 6.

The laminated core 30 of this embodiment is formed from a laminated core manufactured by the manufacturing method described above. Therefore, as shown in FIG. 7, each amorphous alloy piece 80 forming the laminated core 30 has, at the inner periphery, cut surfaces 700 relating to the laser irradiated portion 70 and cut surfaces 720 relating to the non-irradiated portion 72, which are alternately arranged along the circumferential direction. This is also true for the outer periphery (see the portion to be cut 328) which is not shown in FIG. 7.

As described above, the laser irradiated portion 70 is a portion irradiated with a laser, and therefore is more likely to suffer from degradation of magnetic properties due to thermal denaturation than the non-irradiated portion 72. In this regard, in the case of the continuous type laser irradiated portion described above, the laminated core has a laser irradiated portion around its entire circumference, and therefore degradation of magnetic properties due to thermal denaturation can be significant.

In contrast, according to this embodiment, as described above, the laminated core 30 only has the laser irradiated portion 70 locally, so the inconvenience that occurs with a continuous laser irradiated portion (i.e., deterioration of magnetic properties due to thermal denaturation) can be reduced. That is, according to this embodiment, by including the non-irradiated portion 72 in the portion to be cut 320, it is possible to reduce the amount of heat input related to the laser irradiation while minimizing the effect of the laser irradiated portion 70 on the magnetic properties.

In this embodiment, the amorphous alloy pieces 80 may be rotated so that the circumferential positions of the laser irradiated portions 70 are dispersed within the laminated core 30. In this case, the rotation may be performed for one or more amorphous alloy pieces 80. This allows the laser irradiated portions 70 to be dispersed, thereby reducing the possibility of localized deterioration of magnetic properties in the circumferential direction.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or some of the components of the above-mentioned embodiments.

For example, in the above-mentioned embodiment, each amorphous metal ribbon is irradiated with laser separately in the laser irradiation process, but multiple sheets may be stacked and irradiated with laser in the laser irradiation process. This allows multiple amorphous alloy pieces 80 to be produced efficiently. Even in this case, it is possible to appropriately reduce the amount of heat input as described above by setting non-irradiated areas 72.

In addition, in the above-described embodiment, the laser irradiation process is performed so that all of the parts to be cut 320, 322, 328 have discontinuous laser irradiation parts 70, but some of the parts to be cut 320, 322, 328 may be laser irradiated in other ways (for example, such that a continuous laser irradiation part is formed). Alternatively, some of the parts to be cut 320, 322, 328 may be cut by a method other than laser irradiation.

In the above embodiment, the amorphous metal ribbon is cut by a press at the cutting target portion 320 (the same applies to the cutting target portions 322 and 328, and the same applies below), but it may be cut or broken by other methods. For example, the amorphous metal ribbon may be cut by mechanical processing such as a cutter at the cutting target portion 320. Alternatively, the amorphous metal ribbon may be cut by laser irradiation at the cutting target portion 320. That is, after the above-mentioned laser irradiation process, a further laser irradiation process may be performed to change part or all of the non-irradiated portion 72 into a laser irradiated portion similar to the laser irradiated portion 70. In this case, for example, the second laser irradiation may be performed on the non-irradiated portion 72 of the laser irradiated portion 70 and the non-irradiated portion 72, and the third laser irradiation may be performed on the entire circumference of the cutting target portion 320. In this way, by performing the laser irradiation in multiple steps, the amount of heat input per laser irradiation can be reduced, and the possibility of the above-mentioned thermal runaway can be reduced.

In addition, in the above-mentioned embodiment, the laser irradiation in the laser irradiation process may be performed on the amorphous metal ribbon before nanocrystallization, or on a ribbon that has not been nanocrystallized. In this case, the laser irradiation in the laser irradiation process may be realized in a heat input state in which nanocrystallization occurs in the laser irradiation section 70 (i.e., a heat input state in which the first peak described above with reference to FIG. 5 occurs but the second peak does not occur). In this case, nanocrystallization causes localized embrittlement in the laser irradiation section 70, thereby improving the processability in the punching process. In this case, the heat treatment for nanocrystallization of the amorphous alloy piece 80 may be performed after the pressing process and before the lamination process.

70: Laser irradiated area, 72: Non-irradiated area, 30: Laminated core, 320, 322, 328: Area to be cut, 80: Amorphous alloy piece, W: Workpiece (amorphous metal strip)

Claims

preparing a ribbon of an amorphous alloy;
irradiating the ribbon with a laser so that a plurality of laser irradiated portions are formed adjacent to each other via non-irradiated portions along a boundary of a target region in the ribbon;
A cutting or cleaving step of cutting or cleaving the ribbon along the boundary.
The method for manufacturing an amorphous alloy piece according to claim 1, wherein the total length of the non-irradiated portion of the boundary is 1/10 or more of the total length of the laser-irradiated portion of the boundary.
The method for manufacturing an amorphous alloy piece according to claim 1, wherein the total length of the non-irradiated portion of the boundary is equal to or greater than the total length of the laser-irradiated portion of the boundary.
The method for producing amorphous alloy flakes according to claim 1, wherein the cutting or splitting process is performed for each thin ribbon or for multiple thin ribbons.
preparing a ribbon of an amorphous alloy;
irradiating the ribbon with a laser so that a plurality of laser irradiated portions are formed adjacent to each other via non-irradiated portions along a boundary of a target region in the ribbon;
a cutting or breaking step of cutting or breaking the ribbon along the boundary;
A method for manufacturing a laminated core, comprising: a lamination step, before or after the cutting or cleaving step, of forming a laminate of amorphous alloy flakes that are part of the target region in the ribbon.
The method for producing an amorphous metal alloy according to claim 1 or 5, wherein the amorphous metal alloy includes an alloy in which nanocrystals are dispersed in an amorphous matrix.
The method for producing an amorphous metal alloy article according to claim 1 or 5, wherein the cutting or fracture process is performed using an ultrashort pulse laser.
The amorphous alloy flakes are laminated together to form a laminate.
The amorphous alloy piece has an outer circumferential portion or an inner circumferential portion having laser irradiated portions and non-irradiated portions alternately along a circumferential direction,
A laminated core, wherein in the outer circumferential portion or the inner circumferential portion, the total length of the non-irradiated portion is 1/10 or more of the total length of the laser irradiated portion.