JP7344441B2 - Rotor core manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a rotor core.

Patent Document 1 discloses a permanent magnet field type rotor. This rotor includes a connecting hole that passes through the fan-shaped portion of the end plate and the fan-shaped iron plate, and a caulking piece that is cut and raised in the axial direction on the peripheral edge of the connecting hole to connect the laminated plates to each other. It is also described that aluminum is die-cast as a non-magnetic material in the connection hole, and that the non-magnetic material engages with the tip of the caulking piece to firmly connect the laminated plates to each other. The method of fixing the rotating shaft and the fan-shaped iron plate in the rotor is unknown, but referring to FIG. 8 of Patent Document 1, the rotating shaft is provided with a flange-like structure, and this structure is used to fix the rotating shaft. It can be seen that it is done.

Patent Document 2 discloses an outer rotor type stepping motor in which a rotor magnet, which is a cylindrical permanent magnet, is arranged on the outer periphery of a stator. This outer rotor type stepping motor integrates the shaft and rotor frame into a strong rotating torque transmission system by molding a cylindrical thermoplastic resin between the shaft and the inner peripheral surface of the rotor frame. It is stated that.

Utility Model Publication No. 3-001647 Japanese Patent Application Publication No. 6-38489

In recent years, as a method for manufacturing rotor cores, a magnet molding method has been known in which a magnet material is inserted into a magnet hole in a core body on which electromagnetic steel sheets are laminated and sealed with resin. When inserting a shaft into a core body sealed with a magnetic material by the magnetic molding method, dimensional accuracy is required for the outer diameter of the shaft and the inner diameter of the hole in the core body into which the shaft is inserted. In order to improve the ease of inserting the shaft, methods such as warm fitting, in which the core body is warmed and the shaft is inserted, are also used, but when such methods are adopted, the time required to heat and cool the core body is There are concerns that energy such as electricity and electricity will increase. Furthermore, in order to fix the shaft to the core body, it is necessary to provide the shaft with a flange-like structure, thread groove, etc., and to fasten the shaft using a separate nut, washer, etc., and there is room for improvement.

An object of the present invention is to provide a method for manufacturing a rotor core that can improve the ease of inserting a shaft, and can also contribute to simplifying the structure and reducing the number of man-hours.

The method for manufacturing a rotor core of the present invention is a method for manufacturing a rotor core in which a shaft, a magnet material, and a core body are integrally fixed, wherein the shaft is inserted into a shaft hole provided through the center of the core body. a shaft insertion step of inserting the magnetic material into the magnetic hole provided around the shaft hole in the core body; and a magnet insertion step of inserting the magnetic material into the magnetic hole provided around the shaft hole in the core body; , filling the magnet hole with resin to seal the magnet material, and with the shaft inserted into the shaft hole, the shaft is connected to the core body by the resin at both ends in the penetrating direction of the shaft hole. A fixing step of fixing to.

According to the present invention, it is possible to provide a method for manufacturing a rotor core that can improve the ease of inserting a shaft, and can also contribute to simplifying the structure and reducing the number of man-hours.

FIG. 1 is a perspective view schematically showing a rotor core in Example 1. FIG. 2 is a plan view of the rotor core, and is a diagram schematically showing a partially broken resin. FIG. 3 is a cross-sectional view schematically showing a part of the rotor core taken along a line perpendicular to the rotation center axis. FIG. 4(A) is an explanatory diagram showing the state before the shaft insertion process. FIG. 4(B) is an explanatory diagram showing the process of the shaft insertion process. FIG. 4(C) is an explanatory diagram showing the state after the shaft insertion step. FIG. 4(D) is an explanatory diagram showing the magnet material insertion step. FIG. 4(E) is an explanatory diagram showing the heating process. FIG. 5 is an explanatory diagram showing the fixing process. FIG. 6 is an explanatory diagram showing the upper part of FIG. 5 in an enlarged manner. FIG. 7 is a plan view of the rotor core in Example 2, and is a diagram schematically showing a partially broken resin. FIG. 8 is an explanatory diagram showing the fixing process. FIG. 9 is a plan view of the rotor core in Example 3, and is a diagram schematically showing a partially broken resin. FIG. 10 is a diagram showing a groove portion and a groove fitting portion in another embodiment.

Preferred embodiments of the present invention are shown below.
In the fixing step, a first part for fixing the shaft to the core body, a second part filled in the magnetic hole, and a second part connected to the first part and the second part and joined to the core body. and a third portion may be molded from the resin. According to this configuration, by molding the third portion continuous with the first portion and the second portion using resin, the cavity for molding the third portion can be utilized as a flow path for the resin. Furthermore, since this third portion is joined to the core body, it is possible to prevent the core body from deforming from its shape during the fixing process.

The core body has a shape in which a plurality of blocks made of one or more electromagnetic steel sheets are stacked in the axial direction of the shaft, and each block has a hole provided through the center, and the plurality of holes communicate with each other. The shaft hole may be configured as follows. In the shaft insertion step, the shaft may be inserted into the hole for each block. According to this configuration, the ease of inserting the shaft can be improved compared to the case where the shaft is inserted into the shaft hole in a state where a plurality of blocks are stacked.

<Example 1>
In this example, the present invention is applied to manufacturing the rotor core 10 shown in FIG. As shown in FIG. 1, the rotor core 10 includes a shaft 20, a magnet material 30, and a core body 40 that are integrally fixed. This rotor core 10 is a component that constitutes a rotor of a motor. The direction along the rotation center axis of the rotor core 10 is defined as an axial direction X1, and the rotation direction of the rotor core 10 and the opposite direction thereof are defined as the circumferential direction of the rotor core 10. In the following description, each part of the rotor core 10 will be described with the axial direction aligned in the vertical direction, but the rotor core 10 may be manufactured and used in other states.

As shown in FIGS. 1 and 3, the shaft 20 has a cylindrical shape and constitutes the central axis of rotation of the rotor core 10. A resolver rotor 11 and a resolver ring 12 are attached to the shaft 20. A refrigerant flow path 21 through which a refrigerant such as cooling oil flows is formed inside the shaft 20 . The shaft 20 has a refrigerant supply port 22 that supplies cooling oil to the core body 40 from an internal refrigerant flow path 21 .

The magnet material 30 is made of a square columnar permanent magnet, as shown in FIGS. 2 and 3. The rotor core 10 includes a plurality of magnet materials 30. The plurality of magnet materials 30 are arranged at predetermined intervals in the circumferential direction of the rotor core 10.

As shown in FIGS. 2 and 3, the core body 40 has a shaft hole 41 provided through the center and a magnet hole 42 provided around the shaft hole 41. The shaft hole 41 is configured to fit with the shaft 20. The magnet hole 42 has an elliptical shape in plan view and is provided corresponding to each of the plurality of magnet materials 30. Adjacent magnet holes 42 are arranged in a shallow V-shape. Further, the core body 40 has a coolant hole 43 between the shaft hole 41 and the magnet hole 42, through which cooling oil flows.

As shown in FIG. 3, the core body 40 includes a plurality of blocks 50 made of one or more electromagnetic steel plates 55 stacked in the axial direction of the shaft 20. An insulating film (not shown) is provided on both the front and back surfaces of each electromagnetic steel plate 55. The block 50 has a first hole 51 provided through the center, as shown in FIG. 4(B). The first hole 51 is an example of a "hole provided through the center." The core body 40 has a shaft hole 41 configured such that a plurality of first holes 51 communicate with each other. The block 50 further includes a second hole 52 provided around the first hole 51 . The core body 40 is configured with a magnet hole 42 such that a plurality of second holes 52 communicate with each other.

Next, a method for manufacturing the rotor core 10 will be explained. The manufacturing method of the rotor core 10 includes a punching process, a block forming process, a rolling process, a shaft insertion process, a magnet material insertion process, a heating process, a fixing process, a welding process, a process of assembling the resolver rotor 11, and a press-fitting of the resolver ring 12. process, including a magnetization process. In this method of manufacturing rotor core 10, these steps can be performed in this order. Note that in the method for manufacturing the rotor core 10, the steps other than the shaft insertion step, the magnet material insertion step, and the fixing step are optional steps, and may be changed to other steps or may be omitted. Furthermore, the method for manufacturing the rotor core 10 may further include other steps such as an inspection step in addition to the above steps.

In the punching and forming process, an electromagnetic steel plate material is pressed to form an electromagnetic steel plate 55 having a predetermined shape. In the punching and forming process, a first hole 51, a second hole 52, and a third hole corresponding to the refrigerant hole 43 are formed in the electromagnetic steel sheet 55, and a protruding shape corresponding to the key portion 45 that fits into the key groove 27, which will be described later, is formed. form. The block forming process is performed when the block 50 is composed of a plurality of electromagnetic steel plates 55, and the block 50 is formed by stacking a predetermined number of punched electromagnetic steel plates 55. In the block forming process, a plurality of electromagnetic steel sheets 55 are caulked and assembled together.

In the rolling process, the orientations of the plurality of electromagnetic steel sheets 55 are rotated relative to each other in the circumferential direction of the rotor core 10 and stacked. In this transfer process, the stacking of the blocks 50 may be performed in the shaft insertion process described later.

In the shaft insertion step, the shaft 20 is inserted into the shaft hole 41, as shown in FIGS. 4(A) to 4(C). In the shaft insertion process of this embodiment, the shaft 20 is inserted into the first hole 51 for each block 50. In the shaft insertion process, the key groove 27 of the shaft 20 and the key part 45 of the core body 40 are fitted, and the first holes 51, the second holes 52, and the third holes of the plurality of blocks 50 are made to communicate with each other. .

In the shaft insertion step, the shaft 20 may be warmly fitted into the shaft hole 41. Warm fitting is a method of heating the core body 40 to a predetermined temperature and inserting the shaft 20 in a state where the inner diameter of the shaft hole 41 is larger than that at room temperature. In the shaft insertion process, when inserting the shaft 20 into the first hole 51 for each block 50, each block 50 is heated to a predetermined temperature so that the inner diameter of the first hole 51 becomes larger than at room temperature. It is sufficient to insert the shaft 20 in this state. By performing such warm fitting, the shaft insertability can be further improved. In addition, when performing warm fitting, the clearance between the shaft hole 41 and the shaft 20 can be set to 0 or close to 0, and the fitting structure of the shaft hole 41 and the shaft 20 allows the shaft hole 41 and the shaft 20 fixed strength can be obtained. In this case, the fastening load required for fixing the shaft 20 and the core body 40 by the first portion 61, which will be described later, can be reduced. After this warm fitting, and before the temperature of the heated core body 40 is cooled down to room temperature, a fixing process to be described later is performed, thereby shortening the heating and cooling time when manufacturing the rotor core 10, and reducing the power consumption. It is possible to reduce energy consumption such as The "predetermined temperature" in the warm fitting may be lower than the heating temperature of the core body 40 in the heating step.

In the magnet insertion step, the magnet material 30 is inserted into the magnet hole 42, as shown in FIG. 4(D). The magnet material 30 has an outer shape that is one size smaller than the magnet hole 42, and is held at a predetermined position within the magnet hole 42 until it is sealed in a fixing process described later. A gap is formed between the side surface of the magnet material 30 and the inner surface of the magnet hole 42 in a state where the magnet material 30 is held. This gap becomes a flow path for the resin 60 during the fixing process.

The heating process is a process for preheating the core body 40 in order to harden the resin 60 in the subsequent fixing process, as shown in FIG. 4(E). When a warm fitting method is adopted in the shaft insertion process, the amount of energy such as electric power in the heating process can be reduced. As the resin 60, thermosetting resin such as epoxy resin can be used. The heating temperature in the heating step can be set as appropriate depending on the resin 60.

The fixing process can be performed using a manufacturing apparatus 70 as shown in FIG. The manufacturing device 70 includes a fixed mold 71, a movable mold (not shown), a cull plate 76, and a shaft holding section 79. The fixed mold 71 is on which the core body 40 is placed, and includes a fixed mold main body 72, a spacer 73 arranged on the upper surface of the fixed mold main body 72, and a magnet holder that protrudes from the spacer 73 and holds the magnet material 30. It has a section 74. The movable mold is provided so as to be able to move toward and away from the fixed mold 71, and has a resin flow path for supplying the resin 60 to the supply section 77 of the cull plate 76. The cull plate 76 is disposed between the core body 40 and the movable mold, and has a plurality of supply parts 77 that supply the resin 60. The cull plate 76 is provided with a flow path on a surface in contact with the core body 40 for supplying resin from the supply section 77 to the first portion 61 and the second portion 64, respectively. This flow path has a groove shape and constitutes a cavity for molding the third portion 65A to be joined to the upper end surface 40A of the core body 40. The spacer 73 has a cavity for molding a third portion 65B to be joined to the lower end surface 40B of the core body 40. The shaft holding parts 79 , 79 are configured to hold the shaft 20 relative to the core body 40 . The shaft holding parts 79, 79 are inserted, for example, into an upper opening and a lower opening of the coolant flow path 21 of the shaft 20, respectively.

In the fixing step, with the magnet material 30 inserted into the magnet hole 42, the magnet hole 42 is filled with resin 60 to seal the magnet material 30, and with the shaft 20 inserted into the shaft hole 41, The shaft 20 is fixed to the core body 40 with resin 60 at both ends 41A and 41B of the shaft hole 41 in the penetrating direction. Hereinafter, the portion of the resin 60 that fixes the shaft 20 to the core body 40 will be referred to as a first portion 61, and the portion that fills the magnet hole 42 will be referred to as a second portion 64. In the fixing step of this embodiment, the first portion 61, the second portion 64, and the third portions 65A and 65B that are connected to the first portion 61 and the second portion 64 and are joined to the core body 40 are attached to the resin 60. Shaped by. Note that "both ends of the shaft hole in the penetrating direction" refer to the upper end and lower end of the shaft hole 41 that vertically passes through the core body 40. For example, both ends 41A and 41B are included in a range of ±10% of the total length of the shaft hole 41 in the vertical direction (axial direction) with reference to the positions of the end surfaces 40A and 40B of the core body 40 on the hole edge of the shaft hole 41, respectively. It can be an area where At both ends 41A and 41B, the position where the shaft 20 is fixed to the core body 40 may be a position outside the shaft hole 41.

The first portion 61 has slit fitting portions 62A, 62B that fit into the slit portions 24A, 24B, and a groove fitting portion 63 that fits into the groove portion 25 between the slit fitting portions 62A, 62B. Specifically, the shaft 20 has slit portions 24A and 24B located at both ends 41A and 41B of the shaft hole 41. The slit portion 24A has a groove-shaped cutout in the outer circumferential surface 23 of the shaft 20 along a direction perpendicular to the axial direction. A pair of slit portions 24A are provided with the shaft 20 interposed therebetween. The slit portion 24B has the same configuration as the slit portion 24A, except for a different position in the vertical direction. The slit portion 24A and the slit portion 24B are provided at positions that overlap in the vertical direction. The shaft 20 further includes a groove portion 25 that is connected to the slit portions 24A and 24B and has a shape in which the outer circumferential surface 23 is cut out along the axial direction. These slit portions 24A, 24B and groove portion 25 constitute a cavity for molding the first portion 61. That is, the first portion 61 is molded with the resin 60 that is filled into the slit portions 24A, 24B and the groove portion 25 and cured. The shaft 20 has a keyway 27 extending in the axial direction at a position rotated 90 degrees around the rotation center axis from the position of the slit parts 24A, 24B. A key portion 45 provided integrally with the core body 40 fits into this keyway 27 .

The first portion 61 is configured to restrict vertical movement of the shaft 20 with respect to the core body 40 at both end portions 41A and 41B of the shaft hole 41 in the penetrating direction. Specifically, the slit fitting parts 62A and 62B mainly contribute to fixing the shaft 20 in the axial direction X1, and the groove fitting part 63 mainly contributes to fixing the shaft 20 in the circumferential direction. In other words, the first portion 61 prevents the shaft hole 41 from coming off in the axial direction Configure the structure.

The second portion 64 is provided around the magnet material 30 so as to vertically penetrate the core body 40 . A plurality of second portions 64 are formed corresponding to the plurality of magnet holes 42 . The gap in the magnet hole 42 where the second portion 64 is molded becomes a flow path for supplying the resin 60 for molding the third portion 65B located below the core body 40.

As shown in FIGS. 2 and 6, the third portion 65A includes an annular outer ring portion 66, an annular inner ring portion 67 located inside the outer ring portion 66, and an outer ring portion 66 and an inner ring portion. It has a first connecting part 68 that connects the inner ring part 67 and the first part 61 radially, and a second connecting part 69 that connects the inner ring part 67 and the first part 61. The third portion 65A as a whole has a spider web shape (net shape) that spreads over the end surface 40A. The third portion 65A is joined to the end surface 40A of the core body 40. In the end surface 40A of the core body 40, the refrigerant hole 43 opens in a region between the outer ring part 66 and the inner ring part 67, where the first connection part 68 is not provided. Note that the third portion 65B has the same configuration as the third portion 65A except that it is joined to the end surface 40B of the core body 40, and the explanation thereof will be omitted. In this embodiment, the third portion 65A and the third portion 65B, which are arranged to sandwich the core body 40 from above and below, are connected by the first portion 61 at the inner circumferential position and by the second portion 64 at the outer circumferential position. Therefore, the third portion 65A and the third portion 65B can hold down the electromagnetic steel plate 55, which tends to open up and down due to springback, from above and below.

As shown in FIG. 2, the outer ring portion 66 has a shape that connects the upper ends of the plurality of second portions 64 and extends in a meandering manner in the circumferential direction. The outer ring portion 66 is arranged to cover the entire area of the magnet hole 42. With such a configuration, even if the magnet material 30 is chipped or the like, the magnet material 30 can be held in the magnet hole 42 so as not to fall out. By providing such an outer ring portion 66, the end plate disposed to cover the end surfaces 40A, 40B of the core body 40 can be omitted, and the number of parts and assembly man-hours related to the end plate can be reduced. The cavity for molding the outer ring portion 66 is provided with an inlet into which the resin 60 supplied from the supply portion 77 of the cull plate 76 flows (see FIG. 6).

The inner ring part 67 is an annular part that is interposed between the first connection part 68 and the second connection part 69 to merge the resin 60 flowing from the first connection part 68 side and distribute it to the second connection part 69 side. Configure the flow path.

The second connecting portion 69 has a plate shape that extends to the outer peripheral side of the slit fitting portion 62A in the first portion 61. The thickness of the second connecting portion 69 is larger than that of the slit fitting portion 62A, and the upper end thereof is joined to the outer circumferential surface 23 of the shaft 20. The circumferential dimension of the second connecting portion 69 is larger than the circumferential dimension of the slit fitting portion 62A, and both ends thereof are joined to the outer circumferential surface 23 of the shaft 20. By providing such a second connection portion 69, the strength with which the shaft 20 is fixed to the core body 40 by the resin 60 can be improved. It can also be said that the second connecting portion 69 is a portion that fixes the shaft 20 to the core body 40 at both end portions 41A of the shaft hole 41 in the penetrating direction.

In the welding process, part of the outer peripheral surface of the laminated electromagnetic steel sheets 55 is welded by laser welding or the like. Note that this step may be omitted if the laminated electromagnetic steel sheets 55 are sufficiently bonded to each other by the resin 60.

Next, the effects of this embodiment will be explained. According to the method of manufacturing rotor core 10 of this embodiment, sealing of magnet material 30 and fixing of shaft 20 can be performed in the same process. In conventional magnet molding methods, when sealing the magnetic material, a post provided on a mold pallet is generally inserted into the shaft hole. This post is a component that requires accuracy in outer diameter and placement in order to improve the dimensional accuracy of the shaft hole. In this embodiment, since the shaft 20 is inserted into the shaft hole 41 when the magnet material 30 is sealed, a component such as the above-mentioned post is not required. Further, by removing the post from the manufacturing apparatus used in the conventional magnet molding method and setting the shaft holding parts 79, 79, it is possible to use the manufacturing apparatus of the present embodiment, which is preferable.

Furthermore, in this embodiment, since the magnet material 30 is sealed and the shaft 20 is fixed in the same process, the shaft 20 is inserted into the core body 40 after the magnet material 30 is sealed. 20 can be easily inserted. Specifically, since the core body 40 in which the magnet material 30 is sealed has a large dimension in the stacking direction and each layer is fixed, when inserting the shaft, the position and orientation of the core body 40 and the shaft 20 are It was necessary to match them with high precision. In this embodiment, since the shaft insertion step is performed before the step of sealing the magnet material 30, the shaft is 20 can be inserted. Furthermore, in this embodiment, since the shaft insertion step is performed before the step of sealing the magnet material 30, it is also possible to warmly fit the shaft 20 by utilizing the temperature increase in the heating step.

Furthermore, in this embodiment, since the shaft 20 is fixed to the core body 40 using the resin 60, the structure and parts necessary for fixing the shaft 20 to the core body 40 can be simplified or eliminated. Specifically, since the shaft 20 is prevented from coming off in the vertical direction mainly by the slit fitting parts 62A and 62B of the first portion 61, there is no need to provide a flange-like structure or thread groove on the shaft 20, and there is no need to separately provide a flange-like structure or thread groove. There is no need to fasten the shaft 20 using nuts, washers, etc. In addition, although the shaft 20 has a stepped shape at both ends where the outer diameter is smaller than other parts, and has shapes such as slit fitting parts 62A, 62B and groove parts 25, It does not have any protruding structures and has a structure that is easy to manufacture by processing a cylindrical member.

In the fixing process of this embodiment, a first part 61 that fixes the shaft 20 to the core body 40, a second part 64 filled in the magnet hole 42, and a second part 64 that is connected to the first part 61 and the second part 64 and is connected to the core body The third portions 65A and 65B joined to 40 are molded with resin 60. According to this configuration, by molding the third portions 65A and 65B that are continuous to the first portion 61 and the second portion 64 with the resin 60, the cavities for molding the third portions 65A and 65B are formed in the flow path of the resin 60. It can be used as Further, since the third portions 65A and 65B are joined to the core body 40, it is possible to prevent the core body 40 from deforming from its shape during the fixing process. Further, by improving the toughness of the resin 60 and improving the rigidity of the third portions 65A and 65B, it is possible to reduce the number of parts such as end plates.

In the shaft insertion process of this embodiment, the shaft 20 is inserted into the first hole 51 for each block 50. According to this configuration, the insertability of the shaft 20 can be improved compared to the case where the shaft 20 is inserted into the shaft hole 41 in a state in which a plurality of blocks 50 are stacked.

<Example 2>
Next, a method for manufacturing the rotor core 110 according to the second embodiment will be described with reference to FIGS. 7 and 8. The second embodiment is different from the first embodiment in the shapes of the shaft 120 and shaft hole 141, and the shapes of the first portion 161 and third portions 165A and 165B. In the following description of the second embodiment, components similar to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 7, the shaft 120 has a cylindrical shape with an outer circumferential surface 23 having a polygonal shape in a cross section taken in a direction perpendicular to the axial direction X1, and constitutes a central axis of rotation of the rotor core 110. Although the shape of the outer peripheral surface 23 of the shaft 120 is not particularly limited, it is preferably a hexagon or more polygon. In FIG. 7, a decagonal shape is illustrated as the shape of the outer peripheral surface 23 of the shaft 120. The shaft 120 may have chamfered corners of the outer circumferential surface 23. According to the configuration in which the corners of the outer circumferential surface 23 are chamfered, the insertability of the shaft 120 can be improved, and the space between the corners of the outer circumferential surface 23 and the inner circumferential surface of the shaft hole 141 can be used as a flow path for the resin 60. can do. The shaft hole 141 is configured to fit with the shaft 120. The inner peripheral surface of the shaft hole 141 has the same polygonal shape as the outer peripheral surface 23 of the shaft 120 in plan view.

As shown in FIG. 8, the first portion 161 has an upper joint portion 162A that joins to the upper end portion 23A of the outer peripheral surface 23 of the shaft 120 and the upper surface 28 of the stepped portion, and a lower end portion 23B of the outer peripheral surface 23 of the shaft 120. It has a lower joint part 162B to be joined, and an intermediate joint part 163 to be joined to the outer peripheral surface 23 of the shaft 120 between the upper joint part 162A and the lower joint part 162B. The upper joint portion 162A has an L-shaped annular shape when viewed in cross section, and is configured to fit into the stepped portion on the upper side of the shaft 120. The lower joint portion 162B has an annular shape with a rectangular cross section. The vertical dimension of the lower joint portion 162B is larger than the vertical dimension of the third portion 165A, ensuring joint strength with the shaft 120. The intermediate joint portion 163 has a polygonal cylindrical shape.

The first portion 161 is configured to restrict vertical movement of the shaft 120 with respect to the core body 40 at both end portions 41A and 41B of the shaft hole 141 in the penetrating direction. Specifically, the upper joint part 162A and the lower joint part 162B mainly contribute to fixing the shaft 120 in the axial direction X1, and the intermediate joint part 163 mainly contributes to fixing the shaft 120 in the circumferential direction. . In other words, the first portion 161 prevents the shaft hole 141 from coming off in the axial direction Configure the structure.

As shown in FIG. 7, the third portion 165A includes an annular ring portion 166 and a connecting portion 168 that connects the ring portion 166 and the first portion 161 radially. The third portion 165A as a whole has a spider web shape (net shape) that spreads over the end surface 40A. The third portion 165A is joined to the end surface 40A of the core body 40. Note that the third portion 165B has the same configuration as the third portion 165A except that it is joined to the end surface 40B of the core body 40, and the explanation thereof will be omitted. The ring portion 166 has the same configuration as the outer ring portion 66 of Example 1, and its description will be omitted.

According to this embodiment, since the outer circumferential surface 23 of the shaft 120 is polygonal, the fixing strength between the shaft 120 and the shaft hole 141 in the circumferential direction is improved compared to a structure in which the outer circumferential surface of the shaft is circular. I can do it. Therefore, for example, the structure of the rotor core 110 can be simplified by eliminating the keyway of the shaft 120.

<Example 3>
Next, with reference to FIG. 9, a method for manufacturing rotor core 210 according to Example 3 will be described. The third embodiment differs from the second embodiment in the shapes of the shaft 220 and shaft hole 241. In the following description of the third embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The shaft 220 has a plane 29 parallel to the axial direction X1 on the outer circumferential surface 23, and constitutes a rotation center axis of the rotor core 210. Specifically, the shaft 220 has a shape obtained by H-cutting the outer peripheral surface of a cylindrical member, and has flat surfaces 29, 29 that are parallel to each other and have the same width dimension. Note that the shape of the shaft 220 is not limited to this, as long as the outer peripheral surface 23 has a flat surface, and may be a shape obtained by D-cutting the outer peripheral surface of a cylindrical member, an elliptical shape, an oval shape, etc. . The shaft hole 241 is configured to fit with the shaft 220. The inner circumferential surface of the shaft hole 241 has a similar shape to the outer circumferential surface 23 of the shaft 220 in plan view.

According to this embodiment, since the outer circumferential surface 23 of the shaft 220 has the flat surface 29, the fixing strength between the shaft 220 and the shaft hole 241 in the circumferential direction is improved compared to a structure in which the outer circumferential surface of the shaft is circular. I can do it. Therefore, for example, the structure of the rotor core 210 can be simplified by eliminating the keyway of the shaft 220.

<Other embodiments>
The present invention is not limited to Examples 1 to 3 explained in the above description and drawings, and the following embodiments are also included within the technical scope of the present invention.
(1) In the first embodiment described above, the first portion 61 does not need to have the groove fitting portion 63. In this case, for example, the resin 60 may be supplied to the slit fitting portion 62B via the second portion 64 and the third portion 65B. Furthermore, in the second embodiment, the first portion 161 does not need to have the intermediate joint portion 163. In this case, for example, the resin 60 may be supplied to the lower joint portion 162B via the second portion 64 and the third portion 165B.
(2) In the above embodiment, the first portion and the second portion may not be connected at the third portion. In this case, the cull plate includes a first supply part for supplying resin to a cavity for molding the first part, and a second supply part for supplying resin to a cavity for molding the second part. , may have.
(3) In the above embodiment, the rotor core may further include end plates made of stainless steel or the like on both sides of the core body in the axial direction. In this case, the third portion may be provided between the end plate and the core body.
(4) In the above embodiment, the third portion may be joined to only one end surface of both end surfaces of the core body. In this case, the end plate may be provided only on the end surface side of the core body where the third portion is not provided.
(5) In the first embodiment, the groove 25 is provided on the outer circumferential surface 23 of the shaft 20, but the groove 325 may be provided on the inner circumferential surface of the shaft hole 341 as shown in FIG. . Further, the groove fitting portion 63 of the first portion 61 may be configured to fit into the groove portion 325.
(6) In the above embodiments 2 and 3, there may be almost no clearance between the flat surface of the outer circumferential surface of the shaft and the inner circumferential surface of the shaft hole, and the surfaces may be in contact with each other. In this case, the groove 25 of Example 1 or the groove 325 described above may be provided, or the corners of the outer peripheral surface may be chamfered to ensure a resin flow path leading from the upper joint to the lower joint.
(7) In addition to the embodiments described above, the configuration, shape, and position for fixing the shaft to the core body with resin at both ends of the shaft hole in the penetrating direction can be set as appropriate. For example, the shaft fitting portion of Example 1 may be provided at a position inside the shaft hole.

The foregoing examples are for illustrative purposes only and are not to be construed as limiting the invention. Although the invention has been described in terms of exemplary embodiments, the language used in describing and illustrating the invention is to be understood to be in a descriptive and illustrative rather than a restrictive sense. Changes may be made in the form as detailed herein without departing from the scope or spirit of the invention and within the scope of the appended claims. Although reference has been made herein to specific structures, materials and embodiments in the detailed description of the invention, it is not intended to limit the invention to the disclosure herein; rather, the invention is defined by the appended claims. It shall cover all functionally equivalent structures, methods and uses within the scope.

10,110,210...Rotor core 20,120,220...Shaft 30...Magnet material 40...Core body 41,141,241...Shaft hole 41A, 41B...End part 42...Magnet hole 50...Block 51...First hole (hole )
55...Electromagnetic steel plate 60...Resin 61,161...First part 64...Second part 65A, 65B, 165A, 165B...Third part X1...Axis direction

Claims (3)

A method for manufacturing a rotor core in which a shaft, a magnet material, and a core body are integrally fixed,
a shaft insertion step of inserting the shaft into a shaft hole provided through the center of the core body;
a magnet insertion step of inserting the magnet material into a magnet hole provided around the shaft hole in the core body;
With the magnetic material inserted into the magnetic hole, the magnetic hole is filled with resin to seal the magnetic material, and with the shaft inserted into the shaft hole, the shaft hole is penetrated. a fixing step of fixing the shaft to the core body with the resin at both ends in the direction ,
The shaft is
two slit portions located at both ends and having a groove-like shape cut out in the shaft along a direction perpendicular to the axial direction;
a groove portion connected to the two slit portions and having a shape of cutting out the shaft along the axial direction;
The groove portion is located in a portion of the outer circumferential surface of the shaft in a state where the shaft is inserted into the shaft hole, facing the inner circumferential surface of the shaft hole ,
In the shaft insertion step, the shaft is warmly fitted into the shaft hole, and the outer circumferential surface of the shaft and the inner circumferential surface of the shaft hole are brought into contact,
After the shaft is warmly fitted into the shaft hole, the fixing step is performed before the heated core body is cooled to room temperature,
In the fixing step, the outer circumferential surface of the shaft is fixed to the core body by filling the two slits and the groove with the resin. In the fixing step,
a second slit fitting portion that fits into the two slit fitting portions, and a groove fitting portion that fits into the groove portion between the two slit fitting portions, and fixes the shaft to the core body; 1 part and
a second portion filled in the magnet hole;
two third parts connected to the first part and the second part, joined to the core body , and arranged to sandwich the core body from both sides in the axial direction , molded with the resin ,
The method for manufacturing a rotor core according to claim 1, wherein the two third portions are connected by the first portion at an inner circumferential position and by the second portion at an outer circumferential position. The core body is
A plurality of blocks made of one or more electromagnetic steel sheets are stacked in the axial direction of the shaft,
The block has a hole provided through the center,
The shaft hole is configured such that a plurality of the holes communicate with each other,
3. The rotor core manufacturing method according to claim 1 , wherein in the shaft insertion step, the shaft is inserted into the hole for each block.

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