Rotor core

Abstract

Conventional rotor cores had a problem where it was difficult to fix the magnets in place if the ends of the magnets had chamfers. [Solution] A cylindrical laminate S is formed by stacking electromagnetic steel sheets 1, and a magnet M having a chamfered portion 3 at its end is inserted into a slot 2 of the laminate S. Multiple electromagnetic steel sheets corresponding to the chamfered portion 3 of the electromagnetic steel sheets 1 have a notch 4 that is open to the slot 2 side and a void 5 formed by the continuation of the notch 4. The electromagnetic steel sheet 1 that appears at the bottom of the void 5 has an indentation 6 and a protrusion 7 that protrudes toward the magnet M as a result of the formation of the indentation. The protrusion 7 is pressed against the magnet M to fix it, forming a rotor core R, and a magnet M having a chamfered portion at its end is used, and the magnet M is securely fixed in the slot 2.

Description

Technical Field

[0001] The present invention relates to a rotor core used for a rotor of a rotating electrical machine.

Background Art

[0002] As a conventional rotor core, for example, there is one described in Patent Document 1. In Patent Document 1, in a rotor core in which a magnet is accommodated in a through-hole, a concave portion that depresses from the inner surface thereof toward the anti-magnet side is formed in the through-hole, and by plastically deforming the concave portion with tools, the open tip portion of the concave portion is protruded toward the magnet side, and the magnet is fixed in the through-hole by pressing the open tip portion against the magnet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional rotor core, since the concave portion is plastically deformed with tools and the open tip portion is pressed against the magnet, there is a risk of damaging the corner portion of the magnet. In addition, magnets used for rotor cores are generally chamfered to prevent corner defects. On the other hand, in the conventional rotor core, when there is a chamfer at the corner of the magnet, an open tip portion is formed at the chamfer portion, so there is a problem that it is difficult to fix the magnet.

[0005] The present invention has been made in view of the above-described conventional situation, and is a rotor core having a structure in which a magnet having a chamfer portion at an end is inserted into a slot of a laminate formed by laminating a large number of electromagnetic steel sheets, and an object thereof is to provide a rotor core capable of reliably fixing a magnet in the slot.

Means for Solving the Problems

[0006] The rotor core according to the present invention has a structure in which a cylindrical laminate is formed by stacking a large number of electromagnetic steel sheets in the axial direction, and magnets having chamfered ends are inserted into slots in this laminate. In this rotor core, a number of electromagnetic steel sheets corresponding to the chamfered ends have notches that are open to the slot side and voids formed by the continuation of these notches. Furthermore, the rotor core is characterized in that the electromagnetic steel sheets that appear at the bottom of the voids have indentations and protrusions that extend toward the magnet as a result of the formation of the indentations, and the magnets are fixed in the slots by pressing the protrusions against the magnets. [Effects of the Invention]

[0007] In the rotor core according to the present invention, by adopting the above configuration, the protrusions formed by the formation of indentations with a tool such as a punch are formed in a position away from the chamfered portion of the magnet and press against the magnet. As a result, in the rotor core having a structure in which magnets having chamfered portions at their ends are inserted into slots of a laminate made by stacking a large number of electromagnetic steel sheets, the magnets can be securely fixed in the slots. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of a key part showing one embodiment of the rotor core according to the present invention. [Figure 2] Figure 1 is a cross-sectional view of the rotor core along its axial direction. [Figure 3] Figure 1 is a plan view of the rotor core as seen from the axial direction. [Figure 4] These are a plan view (A) and an oblique view (B) of the magnet as seen along its axis. [Figure 5] This is a magnified diagram illustrating the chamfered portion of the magnet. [Modes for carrying out the invention]

[0009] <First Embodiment> The rotor core R shown in Figures 1 to 3 has a structure in which a cylindrical laminate S is formed by stacking a large number of electromagnetic steel sheets 1 in the axial direction (up and down direction in Figure 1), and magnets M having chamfered ends 3 are inserted into slots 2 of this laminate S. This rotor core R, together with a ring-shaped stator (not shown) arranged on the outer circumference, constitutes a rotating electric machine.

[0010] Furthermore, the rotor core R has multiple electromagnetic steel sheets 1 (four from the top in Figure 1) corresponding to the chamfered portion 3 of the electromagnetic steel sheet 1, each having a notch 4 that is open to the slot 2 side, and a void 5 formed by connecting these notches 4.

[0011] Furthermore, the rotor core R has an electromagnetic steel sheet 1 (the fifth electromagnetic steel sheet from the top in Figure 1) that appears at the bottom of the cavity 5, which has an indentation 6 and a protrusion 7 that extends toward the magnet M as a result of the formation of the indentation 6. The magnet M is fixed in the slot 2 by pressing the protrusion 7 against the magnet M. The indentation 6 is formed, for example, by a tool such as a punch P.

[0012] The electromagnetic steel sheet 1 is a circular plate member, and is stacked in multiple layers to form a cylindrical laminate S. Although not shown in the figure, openings such as slot holes and bolt holes are formed by press working. As shown in Figure 3, the laminate 1 has an axial hole H in the center when viewed in the axial direction, and slots 2 and magnets M are arranged at equal intervals in the circumferential direction.

[0013] In the illustrated example, the laminated body S has slots 2 and magnets M arranged at four locations at 90-degree intervals. In each slot 2, a magnet M is placed on the outer circumference side of the laminated body S, and a void 4 is placed on the inner circumference side of the laminated body S, forming two indentations 6 and two protrusions 7.

[0014] In this embodiment, as shown in Figure 2, the rotor core R has magnets M with chamfered portions 3, 3 on both end faces in the axial direction (up and down direction in Figure 2), and the laminate S has notches 1A and voids 5, as well as indentations 6 and protrusions 7 on both sides in the axial direction.

[0015] As a more preferred embodiment, the indentation 6 can adopt a circular shape. That is, a punch (tool) P with a circular tip is used. The protrusion 7 is formed by the metal flow of the electromagnetic steel sheet 1 when the indentation 6 is formed. It can not only cause metal flow in the electromagnetic steel sheet 1 where the indentation 6 is formed, but also in the electromagnetic steel sheet 1 adjacent to its lower side, and can be formed over several electromagnetic steel sheets 1.

[0016] The magnet M has a flat rectangular end face in the axial direction view shown in Fig. 4(A), and as shown in Fig. 4(B), is a cuboid as a whole and has chamfered portions 3 on both end faces in the axial direction. This magnet M is arranged in the laminate S shown in Fig. 3 with the long side of the end face facing the circumferential direction.

[0017] Also, as shown in Fig. 5, the magnet M has a structure where the length A in the direction along the short side (X direction in Fig. 5) of the chamfered portion 3A of the long side among the chamfered portions 3 of the end face is larger than the length B along the axial direction (Z direction in Fig. 5) (A > B). Furthermore, as shown in Fig. 4(A), the inclined surface Fb of the chamfered portion 3B of the short side of the magnet M has a larger area than the inclined surface Fa of the chamfered portion 3A of the long side.

[0018] In the rotor core R having the above configuration, the protrusion 7 formed along with the formation of the indentation 6 is formed at a position where the chamfered portion 3 of the magnet M is removed and comes into pressure contact with the magnet M. Thereby, in the structure where the magnet M having chamfered portions 3 at both ends is inserted into the slot 2 of the laminate S formed by laminating a large number of electromagnetic steel sheets 1, the magnet M can be reliably fixed in the slot 2.

[0019] Also, the above rotor core R adopts a configuration having notch portions 4 and voids 5, as well as indentations 6 and protrusions 7 on both sides in the axial direction of the laminate S, so that both ends of the magnet M can be fixed in the slot 2 to obtain a stronger fixed state.

[0020] Furthermore, since the above rotor core R has chamfered portions 3 on the magnets M, it can prevent defects such as loss at the corners of the magnets M and facilitate the insertion operation into the slots 2. Also, in the above rotor core R, notch portions 4 are provided in a plurality of electromagnetic steel sheets 1 corresponding to the chamfered portions 3 among the numerous electromagnetic steel sheets 1 to form voids 5, thereby securing a space for the punch P to penetrate and ensuring appropriate caulking strength with the indentations 6 and protrusions 7, and it is also possible to eliminate the adhesive for fixing the magnet M.

[0021] Furthermore, in the above rotor core R, in a view in the axial direction of the laminate S, the slots 2 and the magnets M are arranged at equal intervals in the circumferential direction. In each slot 2, the magnet M is arranged on the outer peripheral side of the laminate S, and the void 5 is arranged on the inner peripheral side of the laminate S. Thereby, the rotor core R can caulking-fix the magnet M in the slot 2 without affecting the magnetic path between the rotor core R and the stator.

[0022] Furthermore, by making the indentation 6 circular in shape, the above rotor core R can smoothly form the protrusion 7 and caulking-fix the magnet M with sufficient strength without causing defects such as cracks in the electromagnetic steel sheet 1. The clearance between the slot 2 and the magnet M is not particularly limited, but as an example, the clearance is about 0.08 to 0.24 mm, and the protrusion amount of the protrusion 7 is 0.3 mm or more.

[0023] Furthermore, in the above rotor core R, the magnet M is rectangular in a view in the axial direction and is arranged with its long side facing the circumferential direction of the laminate S. Thereby, in combination with the configuration in which the magnet M is arranged on the outer side in the radial direction of the laminate S and the void 5 is arranged on the inner side, the rotor core R can provide a plurality of indentations 6 and protrusions 7 on the long side of the magnet M and can caulking-fix the magnet M more firmly without affecting the magnetic path between the rotor core R and the stator.

[0024] Furthermore, in the rotor core R described above, the longer sides of the magnet M, which forms a rectangle when viewed in the axial direction, are positioned in the circumferential direction of the laminate S, and the length A in the direction along the shorter side of the chamfered portion 3A of the longer side is made larger than the length B along the axial direction. As a result, the rotor core R described above has a larger surface area on the axial side of the magnet M, so that the position of crimping and fixing by the protrusion 7 can be moved closer to the axial end while maintaining the insertability of the magnet M into the slot 2, thereby reducing the influence on the magnetic field.

[0025] Furthermore, the rotor core R described above has a larger area for the bevel Fb of the chamfered portion 3B on the short side of the magnet M than for the bevel Fa of the chamfered portion 3A on the long side. This makes it easy to insert the rotor core R into the slot 2 while shifting it towards the short side. Moreover, as mentioned above, the rotor core R has a crimping portion on the long side due to the indentation 6 and the protrusion 7, so by reducing the area of ​​the chamfered portion 3A on the long side, the number of electromagnetic steel sheets 1 having the notch 4 can be minimized, making it easier to hold the magnet M and, as a result, improving the reliability of holding the magnet M.

[0026] The rotor core according to the present invention is not limited to the above-described embodiment in terms of its specific configuration, and can be modified as appropriate without departing from the spirit of the present invention. [Explanation of Symbols]

[0027] 1 Electrical steel sheet 2 slots 3. Chamfered section 3A Chamfered section on the long side 3B Chamfered edge on the short side 4 Notches 5 empty space 6. Indentations 7. Protrusion Fa: Bevel of the chamfered edge on the long side Fb Bevel of the chamfered edge on the short side M magnet S Laminate R Rotor Core

Claims

1. A rotor core having a structure in which a cylindrical laminate is formed by stacking a large number of electromagnetic steel sheets in the axial direction, and magnets having chamfered ends are inserted into slots in this laminate, Multiple electromagnetic steel sheets corresponding to the chamfered portion among the electromagnetic steel sheets have notches that are open to the slot side and cavities that are continuous with these notches. The electromagnetic steel sheet appearing at the bottom of the aforementioned cavity has an indentation and a protrusion that extends toward the magnet as a result of the formation of the indentation. A rotor core characterized in that the protrusion is pressed against the magnet and the magnet is fixed in the slot.

2. The magnet has the chamfered portion on both end faces in the axial direction, The rotor core according to claim 1, characterized in that the laminate has the notches and voids, as well as the indentations and protrusions, on both sides in the axial direction.

3. In the axial view, the laminate has the slots and magnets arranged at equal intervals in the circumferential direction. The rotor core according to claim 1 or 2, characterized in that, in each of the aforementioned slots, the magnet is arranged on the outer circumference side of the laminate and the void is arranged on the inner circumference side of the laminate.

4. The rotor core according to claim 1, characterized in that the aforementioned indentation is circular in shape.

5. The magnet is rectangular in shape when viewed in the axial direction, and is arranged with its longer side facing the circumferential direction of the laminate. The rotor core according to claim 3, characterized in that, in the chamfered portion of the long side, the length A in the direction along the short side is greater than the length B along the axial direction (A > B).

6. The rotor core according to claim 5, characterized in that the bevel of the chamfered portion on the short side of the magnet has a larger area than the bevel of the chamfered portion on the long side.

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