JPH0956094A - Manufacture of rotor for synchronous motor and mold used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a rotor for a synchronous motor provided with a magnet fixing member which can firmly fix a plurality of permanent magnets to the surface of a rotor core. SOLUTION: A mold 12 used for molding a magnet fixing member on a rotor 10 is provided with a molding cavity 36 which can house a rotor core 16 and a plurality of permanent magnets 20 so that the core 16 and magnets 20 can face to each other in the same state as that obtained when the manufacture of the rotor 10 is completed and a plurality of retaining members 42 which fixedly retain the magnets 20 to prescribed positions on the cylindrical surface 18 of the core 16. The members 42 move between acting positions at which the front end faces 46 of the members 46 are protruded into the cavity 36 and non-acting positions at which the front end faces 46 are pulled in a recessed section 44 and, at the acting positions, the front end faces 46 are engaged with the side faces 26 of the adjacent magnets 20 housed in the cavity in facing states and fixedly retain the magnets 20 on the cylindrical surface 18 of the core 16 in the peripheral and radial directions. While the core 6 and magnets 20 are in the cavity 36, a molten material is poured and cured in the cavity 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a synchronous motor, and more particularly to a method of manufacturing a rotor of a synchronous motor in which a plurality of permanent magnets are fixed to a cylindrical surface of a rotor core. The invention further relates to a mold used to manufacture such a synchronous motor rotor.

[0002]

2. Description of the Related Art In a rotor of a synchronous motor of the type described above, generally, each permanent magnet has conventionally been fixed to the cylindrical surface of a rotor core by an adhesive means such as an adhesive. Alternatively,
A structure in which a plurality of permanent magnets are fixed to the rotor core by covering the outer peripheral surface of all permanent magnets of the rotor with a tube made of non-magnetic metal material, or by winding a wire made of non-magnetic metal material around all permanent magnets. Is also known.

[0003]

In a rotor structure in which a plurality of permanent magnets are fixed to a rotor core by an adhesive means such as an adhesive, the adhesive means is applied so as to generate a uniform adhesive force to the plurality of permanent magnets. That requires skill
It has a problem of consuming working time. When this rotor structure is applied to a high-torque electric motor or a high-speed electric motor that reaches tens of thousands of revolutions per minute, the radial external force such as magnetic attraction force or centrifugal force acting on the permanent magnet during rotation of the rotor exceeds the adhesive force. At times, peeling may occur at the adhesive interface, causing the permanent magnet to fall off and scatter. Further, there is a possibility that peeling may occur at the adhesive interface due to aging of the adhesive.

On the other hand, if a tube made of a non-magnetic metal material is used, generally, a stronger magnet fixing force than the bonding means can be obtained although it depends on the size and material characteristics of the tube. However, in this case, in order to securely fix the plurality of permanent magnets to the rotor core, it is necessary to mold a tube having an inner diameter substantially equal to the outer diameter of the rotor and to tightly fit the tubes to the outer peripheral surfaces of all the permanent magnets. Therefore, the process of forming and mounting the pipe becomes complicated. In addition, when attaching the tube to the rotor, it is necessary to preliminarily fix each permanent magnet to the surface of the rotor core at least temporarily with an adhesive so that the plurality of permanent magnets do not move from the relative positions when the rotor is manufactured. The rotor manufacturing process becomes more complicated.

Further, when a wire made of a non-magnetic metal material is used, the wire is manually wound around all permanent magnets, so that it is difficult to wind the wire so that it does not protrude from the size of the air gap between the rotor and the stator. At the same time, the reproducibility is large enough to apply the same magnet fixing force to many rotors, making it difficult to manufacture rotors of uniform quality. Further, also in this method, when winding the wire around the rotor, it is necessary to temporarily fix each permanent magnet to the surface of the rotor core in advance with an adhesive so that the plurality of permanent magnets do not move from the relative positions when the rotor is manufactured. is there.

An object of the present invention is to provide a magnet fixing member capable of securely and firmly holding a plurality of permanent magnets on the surface of a rotor core against an external force such as a magnetic attraction force or a centrifugal force acting on the permanent magnets when the rotor rotates. It is an object of the present invention to provide a manufacturing method for easily manufacturing a rotor of a synchronous motor provided with sufficient reproducibility. Another object of the present invention is to provide a mold used for carrying out such a manufacturing method and capable of easily and accurately molding a magnet fixing member.

[0007]

In order to achieve the above object, the first invention of the present application is directed to a rotor of a synchronous motor in which a plurality of permanent magnets are fixed to a cylindrical surface of a rotor core in a circumferentially spaced arrangement. A method of manufacturing, wherein a rotor core and a plurality of permanent magnets can be accommodated in a relative arrangement upon completion of rotor manufacture, and at least a part of a radially outward surface of each permanent magnet placed in this relative arrangement is engaged. A molding cavity that can mold a magnet fixing member that fixes the permanent magnets to the rotor core from a molten material, and a holding portion that can fixedly hold a plurality of permanent magnets in the molding cavity on the cylindrical surface of the rotor core. Prepare a mold equipped with, and place the multiple permanent magnets on the cylindrical surface of the rotor core in the relative arrangement when the rotor manufacturing is completed, and place the rotor core and permanent magnets in the molding cavity of the mold. And a plurality of permanent magnets are fixedly held to the rotor core by the mold holding portion, the molten material is injected into the molding cavity of the mold, and the magnet fixing member is molded by solidifying the molten material to form a magnet. A method of manufacturing a rotor for a synchronous motor, comprising: taking out a rotor, in which a plurality of permanent magnets are fixed to a rotor core by a fixing member, from a mold.

The second invention of the present application is a mold used for manufacturing a rotor of a synchronous motor in which a plurality of permanent magnets are fixed to a cylindrical surface of a rotor core in a circumferentially spaced arrangement. And a plurality of permanent magnets can be accommodated in a relative arrangement upon completion of rotor manufacturing, and the permanent magnets are fixed to the rotor core by engaging at least a part of the radially outward surface of each permanent magnet placed in this relative arrangement. A molding cavity that can mold the magnet fixing member from a molten material, and a holding section that can fixedly hold a plurality of permanent magnets on the cylindrical surface of the rotor core in the molding cavity with the relative arrangement, and the holding section, A plurality of projections protruding from the wall surface of the molding cavity into the molding cavity, the projections being in contact with the side surfaces of the permanent magnets defining the gap between the adjacent permanent magnets on the rotor core, Providing a mold, characterized in that fixedly hold each permanent magnet in the circumferential direction and the radial direction.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the accompanying drawings. In the drawings, the same or similar components are designated by common reference numerals. 1 and 2 are views for explaining a method of manufacturing a rotor 10 of a synchronous motor according to a preferred embodiment of the present invention, which is shown together with a mold 12 for molding a magnet fixing member. FIG. 3 shows a rotor 10 manufactured using the mold 12 shown in FIGS.

As shown in FIGS. 3 (a) and 3 (b), the rotor 10 is fixed to a substantially cylindrical rotor core 16 which is fixed to the shaft 14 by shrink fitting, and a cylindrical surface 18 of the rotor core 16. It is formed from a plurality of permanent magnets 20 (four in the illustrated embodiment). Each of the permanent magnets 20 has substantially the same roof tile shape, and has a cylindrical surface 1 of the rotor core 16.
8, an inner peripheral surface 22 that is in close contact with the inner peripheral surface 8, an outer peripheral surface 24 that extends substantially parallel to the inner peripheral surface 22 and faces a stator (not shown), and a pair of side surfaces 26 that connect the inner peripheral surface 22 and the outer peripheral surface 24. With.

In the rotor 10, a gap 2 is formed between the permanent magnets 20 adjacent in the circumferential direction by the side surface 26 of each permanent magnet 20.
8 are defined. Further, all the permanent magnets 20 are arranged at predetermined positions on the cylindrical surface 18 of the rotor core 16 with a gap 28 having the same shape between adjacent permanent magnets 20. The side surface 26 of each permanent magnet 20 that defines the gap 28 is the outer peripheral surface 2
4 has at least a radially outwardly inclined surface portion 26a extending at an obtuse angle. The inclined surface portion 26a also extends radially outward so as to approach the surface P that connects the axis and the center of gravity of the permanent magnet 20. The side surface shape of such a permanent magnet 20 is determined by a magnet fixing member described later.
Is for locking against the outward force in the radial direction.

In the rotor 10, a plurality of strip-shaped portions 32 of a magnet fixing member 30 formed by filling a resin material or a non-magnetic metal material in each gap 28 between the permanent magnets are arranged. Further, the magnet fixing member 30 is disposed in contact with both axial end faces of the all permanent magnets 20 and is provided with a plurality of strip-shaped portions 3.
It comprises a pair of annular portions 34 interconnecting the two. In the magnet fixing member 30, a plurality of strip-shaped portions 32 are provided in each permanent magnet 20.
Of the permanent magnet 20 is engaged with the inclined surface portion 26a of the side surface 26 of the rotor 26 to fix and hold each permanent magnet 20 at a predetermined position on the cylindrical surface 18 of the rotor core 16 against a radial external force, and a gap 28 having a predetermined shape is provided. The permanent magnets 20 are maintained at regular intervals. Such a magnet fixing member 30 is integrally molded from a molten material such as aluminum or engineering plastic in the mold 12 shown in FIGS. 1 and 2.

As shown in FIGS. 1 and 2, the mold 12 for molding the magnet fixing member 30 on the rotor 10 includes a rotor core 16 fixed to a shaft 14 and a plurality of permanent magnets arranged on its cylindrical surface 18. The magnet 20 and the molding hollow portion 36 having a substantially cylindrical shape capable of accommodating the magnet 20 in a relative arrangement when the rotor is manufactured are provided.
The mold 12 also includes a molded cavity 36 for receiving the shaft 14.
The space 38 is formed so as to communicate therewith. Molding cavity 36
Is defined by a pair of annular wall surfaces 36 a that can be in close contact with both axial end surfaces of the rotor core 16 and a cylindrical wall surface 36 b that can contact the outer peripheral surfaces 24 of the plurality of permanent magnets 20. Further, a second annular wall surface 36c is provided between the annular wall surface 36a and the cylindrical wall surface 36b, the second annular wall surface 36c being spaced apart from both axial end surfaces of the plurality of permanent magnets 20. The wall surface defining the space 38 may or may not contact the shaft 14 (FIG. 2). As shown in FIG. 2, the mold 12 has, for example, a movable side 12 a including a molding cavity 36.
And the fixed side 12b having the sprue 40 can be separated.

Further, the mold 12 holds a plurality (four in the illustrated embodiment) for holding a plurality of permanent magnets 20 in a predetermined position on the cylindrical surface 18 of the rotor core 16 in the molding cavity 36. A member 42 is provided. Each holding member 42
It is movably arranged in a recess 44 formed on the movable side 12a of the mold 12. The recesses 44 open in the cylindrical wall surface 36b of the molding cavity 36 at evenly spaced positions in the circumferential direction, and the gaps 28 between the plurality of permanent magnets 20 housed in the molding cavity 36 are arranged relative to each other when rotor manufacturing is completed. Communicate with.

Each holding member 42 has an operating position (position shown in FIGS. 1 and 2) in which the tip end surface 46 is projected into the molding cavity 36 and a recess 44 by a well-known driving means such as a cylinder device. Is moved to and from the non-actuated position. In the operating position, each holding member 42 has its tip surface 46.
Engages the inclined surface portions 26a of the opposite side surfaces 26 of the adjacent permanent magnets 20 housed in the molding cavity 36 in the above relative arrangement, so that the permanent magnets 20 are placed on the cylindrical surface 18 of the rotor core 16 in the relative position. Hold in place. Further, in the non-acting position, the tip end surface 46 of each holding member 42 has the permanent magnet 20
The side surface 26 is detached from the inclined surface portion 26a so that the rotor 10 after molding the magnet fixing member 30 can be easily taken out from the mold 12.

The tip end surface 46 of the holding member 42 forms a pair of ridges 48 that project into the molding cavity 36 at the operating position and extend substantially parallel to the axis of the rotor core 16 (see FIG. 9A). The protrusion 48 engages with the inclined surface portion 26 a of the opposing side surface 26 of the adjacent permanent magnet 20. In addition, the tip end surface 46 is provided between the protrusions 48 with the holding member 42.
The cylindrical wall surface 3 of the molding cavity 36 when is in the working position.
6b forms a maximum recessed portion arranged on the same circumference as that of 6b. Therefore, the rotor core 16 and the plurality of permanent magnets 2
When 0 is housed in the molding cavity 36 and the space 38 in a relative arrangement upon completion of rotor manufacture, the cylindrical surface 1 of the rotor core 16
8, the side surface 26 of each permanent magnet 20, and the tip end surface 46 of each holding member 42 in the operating position for forming the strip portion 32 (FIG. 3) of the magnet fixing member 30 in the gap 28 between the permanent magnets 20. A cavity is defined. Further, the annular portion 3 of the magnet fixing member 30 is provided between the second annular wall surface 36c of the molding cavity portion 36 and the axial end surfaces of the plurality of permanent magnets 20.
A cavity for molding 4 (FIG. 3) is defined.

A rotor 1 using the mold 12 having the above structure
The procedure for molding the magnet fixing member 30 into zero will be described below. First, the plurality of holding members 42 of the mold 12 are arranged in the operating position, and the molding cavity 36 and the space 38 accommodate the rotor core 16 fixed to the shaft 14 and the plurality of permanent magnets 20 arranged on the cylindrical surface 18 thereof. To do. At this time, each holding member 42
The front end surface 46 of the ridge 48 of the
Is abutted against the inclined surface portion 26a of the side surface 26, thereby holding each permanent magnet 20 fixedly on the cylindrical surface 18 of the rotor core 16 in the circumferential and radial directions. In this way, the plurality of permanent magnets 20 are brought into close contact with the cylindrical surface 18 of the rotor core 16 within the molding cavity 36 and are placed on the cylindrical surface 18 in a relative arrangement upon completion of rotor manufacture, so that A gap 28 having a predetermined shape is defined between the matching permanent magnets 20.

In this state, the molten material is injected under pressure, for example, into the cavities defined by the gaps 28 between the permanent magnets 20 and the cavities defined by both axial end surfaces of the permanent magnets 20 to solidify them. . Thereby, the plurality of strip-shaped portions 32 of the magnet fixing member 30 and the pair of annular portions 34 are integrally molded.
After the magnet fixing member 30 is molded, each holding member 42 of the mold 12 is moved to the non-acting position, and the rotor 10 is taken out of the mold 12.

In the rotor 10 manufactured as described above, the plurality of permanent magnets 20 are mechanically fixed to predetermined positions on the cylindrical surface 18 of the rotor core 16 by the magnet fixing members 30. The magnet fixing force of the magnet fixing member 30 reliably and firmly secures the plurality of permanent magnets 20 to the cylindrical surface 18 of the rotor core 16 against an outward force in the radial direction such as a magnetic attraction force or a centrifugal force when the rotor rotates. It is sufficient to fix and hold the permanent magnet, and there is no fear that the permanent magnet will fall off and scatter, unlike the conventional magnet fixing structure using only the adhesive means, at the adhesive interface. Further, since the magnet fixing member 30 can be formed by a well-known molding method such as injection molding, the magnet fixing work becomes extremely easy as compared with the case of using a tube or wire of a non-magnetic metal material, and a large number of rotors can be used. The rotor can be manufactured with sufficient reproducibility to apply the same magnet fixing force.

In the step of molding the magnet fixing member 30, the plurality of permanent magnets 20 are held at predetermined positions by the action of the holding member 42 until the molten material is solidified. It is not necessary to adhere to the contoured surface 18 in advance by using an adhesive means. Therefore, according to the above configuration, the step of adhering the permanent magnet 20 is omitted, and the working time required for manufacturing the rotor is shortened. In addition, when it is desired to firmly fix the plurality of permanent magnets 20 on the cylindrical surface 18 of the rotor core 16 also in the circumferential direction, the permanent magnets 20 and the cylindrical surface 18 are fixed.
Although it is possible to apply a simple adhesive for work between the and, but unlike the fixing force that resists the external force in the radial direction, the adhesive force does not require uniformity or certainty, so the rotor manufacturing work Don't bother. Further, on the cylindrical surface 18 of the rotor core 16, each gap 28 between adjacent permanent magnets 20 is formed.
A groove (not shown) extending in the axial direction is formed at each position corresponding to, and a band-shaped portion of the magnet fixing member is molded by filling the groove with a molten material. It is possible to firmly fix the plurality of permanent magnets 20 on the cylindrical surface 18 of the rotor core 16 in the circumferential direction without using them at all.

FIGS. 4 and 5 are views for explaining a method of manufacturing a rotor 50 of a synchronous motor according to another embodiment of the present invention, which is shown together with a mold 52 for molding a magnet fixing member.
FIG. 6 shows in cross section a rotor 50 manufactured using the mold 52 shown in FIGS. 4 and 5. The rotor 50 includes a rotor core 16 fixed to the shaft 14 as in the rotor 10 of FIG.
It is formed of a plurality of permanent magnets 20 fixed to the cylindrical surface 18 of the rotor core 16. Permanent magnets 2 adjacent to each other in the circumferential direction
Between 0, the side surface 26 of each permanent magnet 20 causes a gap 2
8 are each defined.

In the rotor 50, a plurality of strip-shaped portions 56 of a magnet fixing member 54 formed by filling a resin material or a non-magnetic metal material into the gaps 28 between the permanent magnets, respectively. Further, the magnet fixing member 54 includes a tubular portion 58 that is in close contact with the outer peripheral surface 24 of the all permanent magnet 20 and connects the plurality of strip portions 56 to each other. Magnet fixing member 54
The cylindrical portion 58 engages with the outer peripheral surface 24 of each permanent magnet 20 to move each permanent magnet 20 to the cylindrical surface 18 of the rotor core 16.
The plurality of strip-shaped portions 56 maintain the evenly-spaced arrangement of the permanent magnets 20 through the gap 28 having a predetermined shape while fixing and holding it against the external force in the radial direction at the predetermined position. Such a magnet fixing member 54 is provided in the mold 52 shown in FIGS.
It is integrally molded from molten materials such as aluminum and engineering plastics.

As shown in FIGS. 4 and 5, the mold 52 for molding the magnet fixing member 54 on the rotor 50 includes a plurality of permanent magnets arranged on the rotor core 16 fixed to the shaft 14 and the cylindrical surface 18 thereof. The magnet 20 and the molding hollow portion 60 having a substantially cylindrical shape capable of accommodating the magnet 20 in a relative arrangement when the rotor is manufactured are provided.
The mold 52 also includes a molded cavity 60 for receiving the shaft 14.
The space 62 is formed so as to communicate with. Mold cavity 60
Is defined by a pair of annular wall surfaces 60 a that can be in close contact with both axial end surfaces of the rotor core 16 and a cylindrical wall surface 60 b that is spaced apart from the outer peripheral surfaces 24 of the plurality of permanent magnets 20. As shown in FIG. 5, the mold 52 can be separated into, for example, a movable side 52a having a molding cavity 60 and a fixed side 52b having a sprue 64.

Further, the mold 52 holds a plurality (four in the illustrated embodiment) for holding a plurality of permanent magnets 20 in a predetermined position on the cylindrical surface 18 of the rotor core 16 in the molding cavity 60. The member 64 is provided. Each holding member 64 is
It is movably arranged in a recess 66 formed on the movable side 52a of the mold 52. The recesses 66 open in the cylindrical wall surface 60b of the molding cavity 60 at evenly spaced positions in the circumferential direction, and the gaps 28 between the plurality of permanent magnets 20 housed in the molding cavity 60 are arranged relative to each other when rotor manufacturing is completed. Communicate with.

Each holding member 64 has an operating position (position shown in FIGS. 4 and 5) in which the tip surface 68 is projected into the molding cavity 60 and a recess 66 by a well-known driving means such as a cylinder device. Is moved to and from the non-actuated position. At the operating position, each holding member 64 has its tip surface 68.
Engage the opposite side surfaces 26 of the adjacent permanent magnets 20 housed in the molding cavity 60 in the relative arrangement described above, and fix the permanent magnets 20 on the cylindrical surface 18 of the rotor core 16 in the relative arrangement fixedly. Hold. Further, in the non-acting position, the tip surface 68 of each holding member 64 is separated from the side surface 26 of the permanent magnet 20, so that the rotor 50 after the magnet fixing member 54 is molded can be easily taken out from the mold 52.

The tip surface 68 of the holding member 64 forms a plurality of protrusions 70 that project into the molding cavity 60 at the operating position (see FIG. 9 (b)). Engage with opposite sides 26. In addition, the tip surface 68 forms a maximum recessed portion between the protrusions 70, which is arranged on substantially the same circumference as the cylindrical wall surface 60b of the molding cavity portion 60 when the holding member 64 is in the operating position. Therefore, the rotor core 16 and the plurality of permanent magnets 20 are arranged relative to each other when the rotor manufacturing is completed, so that the molding cavity 60 and the space 6 are formed.
When accommodated in 2, the gap 28 between the permanent magnets 20 is formed by the cylindrical surface 18 of the rotor core 16, the side surface 26 of each permanent magnet 20, and the tip surface 68 of each holding member 64 in the operating position.
A cavity is defined therein for molding the strip 56 (FIG. 6) of the magnet fixing member 54. Further, a cavity for molding the tubular portion 58 (FIG. 6) of the magnet fixing member 54 is defined between the tubular wall surface 60b of the molding cavity 60 and the outer peripheral surface 24 of the plurality of permanent magnets 20. It

The rotor 5 using the mold 52 having the above structure
The procedure for molding the magnet fixing member 54 into
Since the procedure for molding the magnet fixing member 30 by
Description is omitted. In the mold 52, the tip surface 68 of the holding member 64 is composed of the plurality of protrusions 70, so that the plurality of strip-shaped portions 56 are connected to each other in close contact with the outer peripheral surface 24 of all the permanent magnets 20 of the rotor 50. The magnet fixing member 54 including the curved portion 58 can be molded without impairing the rigidity.

The molds 12 and 52 according to each of the above-described embodiments include a holding member 42 that is movable between an operating position and a non-operating position.
By using 64, a plurality of permanent magnets 20 are fixedly held on the cylindrical surface 18 of the rotor core 16 in a relative arrangement when the rotor is manufactured until the molten material is solidified in the mold. Such a structure is provided so that the rotors 10, 50 can be easily taken out from the molding cavities 36, 60 of the molds 12, 52 after the magnet fixing members 30, 54 are molded. Therefore, depending on the shape of the magnet fixing member to be molded, a configuration is used in which the plurality of permanent magnets are fixedly held on the cylindrical surface of the rotor core by using the holding portion made of the protrusions fixedly arranged in the molding cavity. Can also be

FIGS. 7 and 8 show a mold 72 having such a fixed holding portion together with a rotor 74 before molding the magnet fixing member. Rotor 74 manufactured using the mold 72
Is substantially the same as the rotor 10 shown in FIG. 3, and has a configuration in which the annular portion 34 of the magnet fixing member 30 is omitted.

The mold 72 comprises a rotor core 16 fixed to the shaft 14 and a plurality of permanent magnets 2 arranged on its cylindrical surface 18.
0 is provided with a substantially cylindrical molding cavity portion 76 capable of accommodating 0 and 0 in a relative arrangement upon completion of rotor manufacturing. The mold 72 also has a shaft 14
A space 78 formed in communication with the molding cavity 76 for receiving the space. The molding cavity portion 76 has a pair of annular wall surfaces 76 a that can be in close contact with both axial end surfaces of the rotor core 16 and a cylindrical wall surface 76 that is arranged in contact with the outer peripheral surfaces of the plurality of permanent magnets 20.
and b. In addition, as shown in FIG.
2 is, for example, a movable side 72a having a molding cavity portion 76,
It can be separated into a fixed side 72b having a sprue 80.

The molding cavity portion 76 includes a plurality of permanent magnets 20 at substantially equidistant positions in the circumferential direction of the cylindrical wall surface 76b.
A plurality of (four in the illustrated embodiment) holding portions 82 for fixedly holding the tubular surface 18 of 6 at predetermined positions are provided.
Each holding portion 82 is provided with a gap 2 between the plurality of permanent magnets 20 housed in the molding cavity 76 in a relative arrangement when the rotor is manufactured.
8 are arranged to face each other. Each holding portion 82 has a cylindrical wall surface 7.
A pair of ridges 84 (see FIG. 9A) are provided so as to project from 6b into the molding cavity 76 and extend substantially parallel to the axis of the rotor core 16.

Each of the holding portions 82 is engaged with the opposing side surfaces 26 of the adjacent permanent magnets 20 housed in the molding cavity portion 76 in the relative arrangement at the time of completion of the rotor manufacturing, on the surfaces of the pair of protrusions 84, and a plurality of holding portions 82 are provided. The permanent magnet 20 of the cylindrical surface 1 of the rotor core 16
8 is fixedly held in the above relative arrangement. Therefore,
When the rotor core 16 and the plurality of permanent magnets 20 are housed in the molding cavity 76 and the space 78 in the above relative arrangement, the cylindrical surface 18 of the rotor core 16, the side surface 26 of each permanent magnet 20, and the ridge 84 of each holding portion 82. Depending on the surface, the permanent magnet 2
A cavity for molding the strip portion 32 (FIG. 3) of the magnet fixing member 30 is defined in the gap 28 between the zeros.

The rotor 7 is manufactured by using the mold 72 having the above structure.
The procedure for molding the magnet fixing member 30 including only the strip portion 32 in 4 is the same as the procedure for molding the magnet fixing member 30 by the mold 12 of FIG. . The magnet fixing member 30 formed by the mold 72 is a portion that interferes with the protrusion 84 of the holding portion 82 of the mold 72 in the longitudinal direction (the annular portion 34 in FIG. 1).
Therefore, the rotor 74 can be easily taken out from the molding cavity portion 76 of the mold 72 after the magnet fixing member 30 is molded even if the fixed holding portion 82 is adopted.

The projections or ridges formed on the tip end surface of the holding member or the holding portion can hold a plurality of permanent magnets in a predetermined position with respect to the rotor core in the mold, and can form a gap between adjacent permanent magnets. Provided that the magnet fixing member can be molded, it can have various shapes as shown in FIG. 9, for example. FIG. 9A shows the same as the ridges 48, 84 formed on the tip surface 46 of the holding member 42 of the mold 12 shown in FIG. 1 and the holding portion 82 of the mold 72 shown in FIG. 7.
FIG. 9B shows the same thing as the projection 70 formed on the tip surface 68 of the holding member 64 of the mold 52 shown in FIG. FIG.
(C) is a modification of the protrusion. 9 (b) and 9 (c)
After the magnet fixing member is molded, the protrusions shown in are formed on the tip surface of the holding member movable between the operating position and the non-operating position so as to enable the removal of the rotor from the molding cavity of the mold. Need to

[0035]

As is apparent from the above description, according to the present invention, the rotor core and the plurality of permanent magnets can be accommodated in the relative arrangement when the rotor manufacturing is completed, and the radius of each permanent magnet placed in this relative arrangement can be accommodated. A molding cavity in which a magnet fixing member that engages at least a part of the surface facing outward and fixes the permanent magnets to the rotor core can be molded from a molten material, and a plurality of permanent magnets in the molding cavity on the cylindrical surface of the rotor core. Since a plurality of permanent magnets are fixedly held to the rotor core by the holding portion of the mold when the magnet fixing member is molded by using a mold having a holding portion that can be fixedly held, The step of adhering the magnet to the cylindrical surface of the rotor core by the adhering means can be omitted, and the rotor manufacturing process is simplified. Therefore, according to the present invention, there is provided the magnet fixing member capable of reliably and firmly fixing and holding the plurality of permanent magnets to the surface of the rotor core against the external force such as the magnetic attraction force or the centrifugal force acting on the permanent magnets when the rotor rotates. The rotor of the synchronous motor can be easily manufactured with sufficient reproducibility.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a method of manufacturing a rotor of a synchronous motor according to a preferred embodiment of the present invention, which is a cross-sectional view of a mold and a rotor housed in the mold taken along line I-I of FIG. Show.

2 is a cross-sectional view taken along the line II-II in FIG.

3 is a diagram of a rotor manufactured using the mold of FIG.
3A is a cross-sectional view taken along line III-III, and FIG.

FIG. 4 is a diagram illustrating a method of manufacturing a rotor of a synchronous motor according to another preferred embodiment of the present invention, in which a mold and a rotor housed in the mold are cross-sectional views taken along line IV-IV in FIG. Shown in the figure.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is a cross-sectional view of a rotor manufactured using the mold of FIG.

7 is a diagram illustrating a method of manufacturing a rotor of a synchronous motor according to still another preferred embodiment of the present invention, in which the mold and the rotor housed in the mold are taken along line VII-VII in FIG. Shown in cross-section.

8 is a sectional view taken along the line VIII-VIII in FIG. 7.

9 (a) to 9 (c) are two views of a modified example of the protrusion formed on the tip surface of the holding member.

[Explanation of symbols]

 10, 50, 74 ... Rotor 12, 52, 72 ... Mold 14 ... Shaft 16 ... Rotor core 18 ... Cylindrical surface 20 ... Permanent magnet 28 ... Gap 30, 54 ... Magnet fixing member 36, 60, 76 ... Molding cavity 42, 64 ... Holding member 46, 68 ... Tip surface 48, 84 ... Projection 70 ... Projection

Claims (2)

[Claims] 1. A method of manufacturing a rotor for a synchronous motor, comprising a plurality of permanent magnets fixed to a cylindrical surface of a rotor core in a circumferentially spaced arrangement, wherein the rotor core and the plurality of permanent magnets are provided relative to each other when the rotor manufacturing is completed. A molded cavity that can be housed in a configuration and that can be molded from a molten material to form a magnet fixture that engages at least a portion of the radially outwardly facing surface of each permanent magnet in the relative configuration to secure the permanent magnet to the rotor core. And a holding part capable of fixedly holding a plurality of permanent magnets on the cylindrical surface of the rotor core in the relative arrangement in the molding cavity, and a plurality of permanent magnets are arranged in the relative arrangement when the rotor manufacturing is completed. With the magnets arranged on the cylindrical surface of the rotor core, the rotor core and the permanent magnets are housed in the molding cavity of the mold, and a plurality of permanent magnets are held by the holder of the mold. Fixedly holding the molten material into the molding cavity of the mold, solidifying the molten material to mold the magnet fixing member, and fixing the plurality of permanent magnets to the rotor core by the magnet fixing member. A method of manufacturing a rotor of a synchronous motor, comprising: the step of taking out the obtained rotor from the mold. 2. A mold used for manufacturing a rotor of a synchronous motor, wherein a plurality of permanent magnets are fixed to a cylindrical surface of a rotor core in a circumferentially spaced arrangement, wherein the rotor core and the plurality of permanent magnets are formed. A magnet fixing member that can be accommodated in a relative arrangement after completion of manufacture of the rotor and that engages at least a part of a radially outward surface of each permanent magnet placed in the relative arrangement to fix the permanent magnets to the rotor core is a molten material. And a holding part capable of fixedly holding a plurality of permanent magnets on the tubular surface of the rotor core in the relative arrangement in the forming cavity, the holding part being a part of the forming cavity. It is composed of a plurality of projections protruding from the wall surface into the molding cavity, and these projections are brought into contact with the side surfaces of the permanent magnets defining the gaps between the adjacent permanent magnets on the rotor core, thereby Be securely held in the direction and the radial direction, the type characterized by.