WO2024070043A1 - Method for manufacturing rotor, rotor, and ipm motor having said rotor - Google Patents

Abstract

[Solution] A method for manufacturing a rotor in which a magnet is held in a rotor core. This method for manufacturing a rotor includes: a magnet insertion step for inserting the magnet inside a magnet insertion hole in the rotor core; a rotor core holding step for using a plate, which has a pin insertion hole into which a swage pin can be inserted, to cover, from a lamination direction, at least a portion of an end face in the lamination direction of the rotor core in which the magnet has been inserted, and using the plate to press the rotor core in the lamination direction; and a swage step for using the swage pin, which has been inserted into the pin insertion hole, to swage the rotor core in the lamination direction so as to hold the magnet inside the magnet insertion hole. In the rotor core holding step, the rotor core is held in a state in which a relief portion into which the plastically-deformed steel plate enters is provided between the plate and a swage surface contacted by the swage pin. In the swage step, the rotor core in the state of being held by the plate is swaged in the lamination direction by the swage pin.

Description

Rotor manufacturing method, rotor, and IPM motor having said rotor

The present invention relates to a method for manufacturing a rotor, a rotor, and an IPM motor having the rotor.

In a rotor in which a magnet is held in an accommodating hole that penetrates the rotor core in the axial direction, a configuration is known in which the magnet is held by plastically deforming a portion of the accommodating hole. For example, the rotor described in Japanese Unexamined Patent Publication No. 2013-34363 has a recess that is recessed in the axial direction from the axial end face of the rotor core. The recess extends radially inward from the accommodating hole in which the magnet is accommodated. In other words, the recess is located radially inward of the accommodating hole of the rotor core. The rotor presses the open end that opens toward the magnet side against the magnet due to the plastic deformation of the recess. In this way, the rotor holds the magnet in the accommodating hole.

In the manufacturing method of the rotor, first, the magnets are inserted into the housing holes of the rotor core from the axial direction. Next, with the magnets inserted, the rotor core is staked (crimped) from both sides in the axial direction using a staking jig.

In the rotor core, the radial center of the recess is pushed in the axial direction by the staking jig, which is larger than the width of the recess. Each circumferential side wall of the recess is plastically deformed radially outward by the staking jig. As a result, the open tip is pushed radially outward by the plastic deformation of each circumferential side wall and comes into contact with the magnet. The magnet is held in the accommodating hole by coming into contact with the open tip.

Japan Publication No. 2013-34363

The magnet is contacted by the corners formed by the inner surface of the accommodating hole and the circumferential sidewalls due to staking. A force is concentrated on the surface portion of the magnet where the corners are in contact, pressing the magnet radially outward due to point contact. As a result, there is a possibility that excessive stress will be generated in the portion of the magnet where the corners are in contact during staking. Therefore, a configuration is desired that does not generate excessive stress in the magnet when the magnet is fixed to the rotor core by crimping.

The object of the present invention is to provide a manufacturing method for a rotor in which magnets located in magnet insertion holes in a rotor core are held in the rotor core by crimping the rotor core, and a rotor manufacturing method in which excessive stress is not generated in the magnets when the magnets are fixed to the rotor core by crimping.

The manufacturing method of a rotor according to one embodiment of the present invention is a manufacturing method of a rotor having a plurality of steel plates stacked in the thickness direction and magnet insertion holes penetrating the plurality of steel plates in the stacking direction, in which magnets located in the magnet insertion holes are held in the rotor core by crimping the rotor core.

The manufacturing method of the rotor includes a magnet insertion process of inserting the magnet into the magnet insertion hole, a rotor core holding process of covering at least a part of the end face in the lamination direction of the rotor core into which the magnet has been inserted from the lamination direction with a plate having a pin insertion hole into which a crimping pin for crimping the rotor core can be inserted and applying pressure in the lamination direction to at least one end face in the lamination direction of the rotor core with the plate, and a crimping process of crimping the rotor core in the lamination direction with a crimping pin inserted into the pin insertion hole to hold the magnet in the magnet insertion hole.

In the rotor core holding process, the rotor core is held with a clearance between the crimping surface where the crimping pin contacts and the plate into which the plastically deformed steel plate can fit. In the crimping process, the rotor core held by the plate is crimped in the stacking direction by the crimping pin.

A rotor according to one embodiment of the present invention includes a rotor core having a plurality of steel plates stacked in the thickness direction and magnet insertion holes penetrating the plurality of steel plates in the stacking direction, and magnets inserted into the magnet insertion holes, the magnets being held within the magnet insertion holes of the rotor core. The portion of the rotor core that is in contact with the magnets by crimping protrudes in the stacking direction beyond the crimping surface of the rotor core that is crimped.

In addition, an IPM motor according to one embodiment of the present invention has the rotor and a stator having a stator coil and a stator core.

The rotor manufacturing method, rotor, and IPM motor having the rotor according to one embodiment of the present invention can realize a configuration in which excessive stress is not generated in the magnet when the magnet is fixed to the rotor core by crimping.

FIG. 1 is a cross-sectional view showing a schematic configuration of an IPM motor according to an embodiment. FIG. 2 is a perspective view showing a schematic configuration of the rotor according to the embodiment. FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a process diagram showing an example of a method for manufacturing a rotor according to an embodiment. FIG. 5 is a diagram illustrating an example of a magnet insertion process according to the embodiment. FIG. 6 is a diagram illustrating an example of a rotor core holding step according to the embodiment. FIG. 7 is a diagram illustrating an example of a crimping step according to the embodiment. FIG. 8 is a perspective view showing a schematic configuration of a rotor according to the second embodiment. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. FIG. 10 is a diagram illustrating an example of a magnet insertion process according to the second embodiment. FIG. 11 is a diagram illustrating an example of a rotor core holding step according to the second embodiment. FIG. 12 is a diagram illustrating an example of a crimping step according to the second embodiment.

Below, exemplary embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or equivalent parts in the drawings will be given the same reference numerals and their description will not be repeated. Furthermore, the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components or the dimensional ratios of each component.

In the following description, the direction parallel to the central axis P of the rotor 2 is referred to as the axial direction, the direction perpendicular to the central axis P is referred to as the radial direction, and the direction along the arc centered on the central axis P is referred to as the circumferential direction. However, these definitions of directions are not intended to limit the orientation of the motor 1 when in use.

In the following description, the thickness direction refers to the direction perpendicular to the surface of the plate-like member that has the largest area.

In the following description, stacking refers to a state in which at least a portion of a plurality of plate-like members are positioned overlapping each other when viewed in the thickness direction of the plate-like members, and adjacent plate-like members are in close contact with each other.

In the following description, the direction in which the multiple steel plates 23 are stacked in the thickness direction is referred to as the stacking direction. In addition, in the following description, the stacking direction is the same as the axial direction, which is a direction parallel to the central axis P of the rotor 2. However, there is no intention to limit the orientation of the rotor 2 during use by defining this direction.

In addition, in the following explanation, "same" does not only mean "same in the strict sense," but also includes the extent to which something can be considered substantially the same.

In addition, in the following explanation, the expressions "fixing," "connecting," "joining," "attaching," etc. (hereinafter referred to as "fixing, etc.") include not only cases where members are directly fixed, etc. to each other, but also cases where they are fixed, etc. via other members. In other words, in the following explanation, the expression "fixing, etc." includes the meaning of direct and indirect fixing, etc. between members.

(Embodiment 1)
(Motor configuration)
Fig. 1 is a cross-sectional view showing a schematic configuration of a motor 1 according to a first embodiment. The motor 1 is an IPM (Interior Permanent Magnet) motor. As shown in Fig. 1, the motor 1 has a rotor 2, a stator 3, a housing 4, and a shaft 20. The rotor 2 rotates about a central axis P relative to the stator 3. In this embodiment, the motor 1 is a so-called inner rotor type motor in which the rotor 2 is located inside the cylindrical stator 3 so as to be rotatable about the central axis P.

The rotor 2 has a rotor core 21 made of multiple laminated steel plates 23, and magnets 22. The rotor 2 is located radially inward of the stator 3 and is rotatable relative to the stator 3. The shaft 20 is fixed to the rotor core 21 with the shaft 20 passing axially through the through hole 21a. This allows the rotor core 21 to rotate together with the shaft 20. The detailed configuration of the rotor 2 will be described later.

The stator 3 is housed in the housing 4. In this embodiment, the stator 3 is cylindrical. The rotor 2 is located radially inward of the stator 3. In other words, the stator 3 is located radially opposite the rotor 2. The rotor 2 is located radially inward of the stator 3 and rotatable about the central axis P.

The stator 3 has a stator core 31 and a stator coil 32. The stator coil 32 is wound around the stator core 31. The stator 3 is a known stator, and detailed description of its configuration is omitted.

The housing 4 is cylindrical and extends along the central axis P. In this embodiment, the housing 4 is cylindrical with an internal space capable of housing the rotor 2 and the stator 3. A detailed description of the configuration of the housing 4 is omitted.

(Rotor configuration) Next, the detailed configuration of the rotor 2 will be described. Figure 2 is a perspective view showing the general configuration of the rotor 2 according to the first embodiment. As shown in Figure 2, the rotor 2 has a rotor core 21 and a plurality of magnets 22.

The rotor core 21 is columnar and extends along the central axis P, and has multiple steel plates 23 and multiple magnet insertion holes 21b. The multiple steel plates 23 are stacked in the thickness direction. The magnet insertion holes 21b extend in the axial direction. Each steel plate 23 is a disk-shaped electromagnetic steel plate formed into a predetermined shape. In the following, an example will be described in which the rotor 2 has one rotor core 21. The rotor may be configured by stacking multiple rotor core blocks, each having a configuration similar to the rotor core described in this embodiment, in the axial direction.

When viewed from the stacking direction, the rotor core 21 has a through hole 21a in the center. The rotor core 21 has multiple magnet insertion holes 21b positioned at predetermined intervals in the circumferential direction. The multiple magnet insertion holes 21b penetrate the rotor core 21 in the stacking direction. Magnets 22 are inserted into these magnet insertion holes 21b.

When viewed from the stacking direction of the rotor core 21, the magnet insertion hole 21b has a shape that is long in one direction. In this embodiment, one of a pair of inner surfaces that form the long side of the magnet insertion hole 21b when viewed from the axial direction is located radially inward of the rotor core 21. The other of the pair of inner surfaces is located radially outward of the rotor core 21. Hereinafter, of the inner surfaces of the magnet insertion hole 21b, the inner surface located radially inward is referred to as the inner insertion hole inner surface 21c, and the inner surface located radially outward is referred to as the outer insertion hole inner surface 21d.

The magnet 22 is a rectangular parallelepiped with an end face shape that can be inserted into the magnet insertion hole 21b. The end face of the magnet 22 has a long side that is approximately the same length as the long side of the magnet insertion hole 21b when viewed from the stacking direction. In addition, the length of the magnet 22 in the direction perpendicular to the end face is approximately the same as the length in the stacking direction at the magnet insertion hole 21b.

Each of the multiple steel plates 23 has an opening 23a that forms part of the magnet insertion hole 21b.

The steel plates 23 located at both ends of the stacking direction among the multiple steel plates 23 have crimped surfaces 23b that are crimped in the stacking direction. The crimped surfaces 23b are located on the outer surfaces in the thickness direction of the steel plates 23 located at both ends of the rotor core 21 in the stacking direction. The crimped surfaces 23b are crimped in the stacking direction by crimp pins A, which will be described later (see Figure 7).

A part of the crimping surface 23b is plastically deformed by crimping. That is, the crimping surface 23b has two crimp marks 23c that have been plastically deformed by the crimping pin A. The two crimp marks 23c are located radially inward from the magnet insertion hole 21b and in the vicinity of the magnet insertion hole 21b. That is, the steel plate 23 is plastically deformed toward the magnet insertion hole 21b by crimping.

Figure 3 is a cross-sectional view taken along line III-III in Figure 2. As shown in Figure 3, part of the inner insertion hole inner surface 21c of the rotor core 21 is plastically deformed inwardly of the magnet insertion hole 21b due to crimping. In other words, at least one steel plate 23 crimped in the stacking direction by crimping pin A has part of the inner insertion hole inner surface 21c, which is the inner peripheral surface of the opening 23a with low rigidity, protruding toward the magnet 22.

A portion of the inner insertion hole inner surface 21c that protrudes toward the magnet 22 is in contact with the magnet 22 in the magnet insertion hole 21b. The magnet 22 is pressed toward the outer insertion hole inner surface 21d by the contacting portion of the inner insertion hole inner surface 21c. This causes the magnet 22 to be sandwiched between the portion of the inner insertion hole inner surface 21c and the outer insertion hole inner surface 21d. Therefore, the magnet 22 is held in the magnet insertion hole 21b in a state where it is pressed against the outer insertion hole inner surface 21d by the plastically deformed portion of the inner insertion hole inner surface 21c.

Furthermore, at least a portion of the plastically deformed steel plate 23 between the position where the crimping pin A comes into contact and the magnet insertion hole 21b protrudes in the stacking direction beyond the crimping surface 23b. In other words, at least a portion of the steel plate 23 that has been plastically deformed by crimping protrudes outward in the stacking direction beyond the stacking direction position of the crimped steel plate 23 in the rotor core 21.

In the above-described configuration, at least a portion of the plastically deformed steel plate 23 in the rotor core 21 between the position where the crimping pin A contacts and the magnet insertion hole 21b protrudes beyond the crimping surface 23b toward the end of the rotor core 21 in the lamination direction. In other words, a portion of the steel plate 23 is plastically deformed in the lamination direction of the rotor core 21 by the force applied by the crimping pin A.

As a result, the force applied to the magnets 22 by the plastically deformed steel plates 23 is dispersed by plastic deformation in the stacking direction. Therefore, the rotor core 21 does not generate excessive stress on the magnets 22. Therefore, the rotor core 21 can crimp the magnets 22 with a stronger force than when the force applied to the magnets 22 is not dispersed in the stacking direction. This makes it possible to increase the force required to hold the magnets 22 within a range where excessive stress is not generated. In addition, the portion in contact with the magnets 22 is less likely to elastically deform even if a force is applied to the magnets 22 in the radial direction due to magnetization or motor operation. Therefore, the rotor core 21 can stably hold the magnets 22 within the magnet insertion holes 21b.

Furthermore, in the above-mentioned configuration, the motor 1 has a rotor 2 and a stator 3 having a stator coil 32 and a stator core 31. This makes it possible to realize a motor 1 equipped with a rotor 2 having the above-mentioned effects.

(Rotor manufacturing method)
Next, a method of manufacturing the rotor 2 will be described, in which the rotor 2 is manufactured from the rotor core 21, which is made up of a plurality of steel plates 23 stacked in the thickness direction, and the magnets 22. Only crimping in one direction of stacking will be described below.

FIG. 4 is a process diagram showing an example of a manufacturing method for the rotor 2 according to the first embodiment. As shown in FIG. 4, the manufacturing method for the rotor 2 according to the first embodiment includes a magnet insertion process S1, a rotor core holding process S2, and a crimping process S3. The manufacturing method for the rotor 2 is performed in the order of the magnet insertion process S1, the rotor core holding process S2, and the crimping process S3.

FIG. 5 is a diagram showing an example of the magnet insertion process S1 according to the first embodiment. As shown in FIG. 5, the magnet insertion process S1 is a process of inserting a magnet 22 into the magnet insertion hole 21b of the rotor core 21. In the magnet insertion process S1, the rotor core 21 is placed on one of a pair of plates B. One end face of the rotor core 21 in the stacking direction is in contact with a contact surface B2, which is one end face of one of the plates B in the thickness direction.

Next, magnets 22 are inserted into each magnet insertion hole 21b on the other end face of the rotor core 21 placed on one plate B by an insertion device (not shown). The magnets 22 are inserted into the magnet insertion holes 21b to a position where one longitudinal end contacts one plate B. As a result, the magnets 22 are held in the magnet insertion holes 21b.

Figure 6 is a diagram showing an example of the rotor core holding process S2 according to the first embodiment. As shown in Figure 6, the rotor core holding process S2 is a process of holding the rotor core 21, in which the magnets 22 are inserted into the magnet insertion holes 21b, in a state in which the rotor core 21 is pressed in the stacking direction by a pair of plates B.

In the rotor core holding process S2, the contact surface B2 of one plate B is brought into contact with the other end face in the stacking direction of the rotor core 21 placed on one plate B by a driving device (not shown). Furthermore, the rotor core 21 is pressurized in the stacking direction by the pair of plates B. As a result, the rotor core 21 is held by the pair of plates B located at both ends in the stacking direction while being pressurized. In addition, at least the portion of the other end face in the stacking direction of the rotor core 21 that includes the magnet insertion hole 21b is covered by the other plate B.

The pair of plates B each have two pin insertion holes B1 into which a crimping pin A can be inserted. The two pin insertion holes B1 penetrate the plate B in the thickness direction. Therefore, in the rotor core 21, the portions that overlap with the pin insertion holes B1 when viewed from the stacking direction are crimped by the crimping pin A. In this way, the pair of plates B determine the crimping position in the rotor core 21. In this embodiment, the two pin insertion holes B1 are located radially inward of the magnet insertion hole 21b and in the vicinity of the magnet insertion hole 21b when viewed from the stacking direction.

The pair of plates B have two recesses B3 recessed from each contact surface B2 in the thickness direction to a depth equivalent to the thickness of the steel plate 23. When the pair of plates B and the rotor core 21 are in contact with each other, the two recesses B3 are recessed outward in the stacking direction of the rotor core 21. When the pair of plates B and the rotor core 21 are in contact with each other, the two recesses B3 extend from each pin insertion hole B1 toward the magnet insertion hole 21b when viewed from the stacking direction. In this embodiment, the recesses B3 extend from the pin insertion hole B1 to a position overlapping with the magnet insertion hole 21b when viewed from the stacking direction. The recesses B3 form gaps between the one plate B and the other plate B and the steel plate 23. In other words, the recesses B3 are formed as escape portions into which the steel plate 23 plastically deformed in the stacking direction enters by the crimping process S3 described later.

FIG. 7 is a diagram showing an example of the crimping process S3 according to the first embodiment. As shown in FIG. 7, the crimping process S3 is a process in which both ends of the rotor core 21 in the stacking direction are crimped in the stacking direction with crimp pins A to hold the magnets 22 in the magnet insertion holes 21b. Below, only the crimping in the other stacking direction will be described.

In the crimping process S3, the rotor core 21 is further pressurized in the stacking direction by a pair of plates B. With the rotor core 21 in a pressurized state, the crimping pin A is inserted into the pin insertion hole B1 of the other plate B by a drive device (not shown). The crimping pin A comes into contact with the crimping surface 23b of the steel plate 23 with which the other plate B is in contact.

The crimping pin A is pressed in the stacking direction by a drive device (not shown) radially inward from the magnet insertion hole 21b in the steel plate 23 and near the magnet insertion hole 21b. As a result, at least one of the multiple steel plates 23 is crimped near the magnet insertion hole 21b by the crimping pin A, with the outer surface of the steel plate 23 that contacts the other plate B serving as the crimping surface 23b.

A part of the inner insertion hole inner surface 21c of the rotor core 21 is plastically deformed inwardly towards the magnet insertion hole 21b by crimping. In other words, the steel plate 23 crimped in the stacking direction by the crimping pin A has the inner insertion hole inner surface 21c, which is the inner peripheral surface of the opening 23a with low rigidity, plastically deformed towards the magnet 22.

A portion of the inner insertion hole inner surface 21c that has been plastically deformed inwardly by crimping into the magnet insertion hole 21b comes into contact with the magnet 22. Furthermore, the portion of the inner insertion hole inner surface 21c presses the magnet 22 against the outer insertion hole inner surface 21d. As a result, the magnet 22 is held in the magnet insertion hole 21b by the frictional force that occurs between the portion of the inner insertion hole inner surface 21c that has been plastically deformed by crimping and the outer insertion hole inner surface 21d.

In addition, at least a portion of the crimped steel plate 23 that overlaps with the recess B3 when viewed from the stacking direction is plastically deformed outward in the stacking direction. That is, at least a portion of the steel plate 23 that is crimped in the stacking direction by the crimping pin A is plastically deformed outward in the stacking direction when viewed from the stacking direction, which overlaps with the recess B3 that is not in contact with the other plate B. The portion that is plastically deformed outward in the stacking direction enters the recess B3.

In the manufacturing method configured as described above, in the rotor core holding step S2, the stacking direction end face of the rotor core 21, in which multiple steel plates 23 are stacked, is pressed in the stacking direction by a pair of plates B. At this time, between the steel plate 23 and the other plate B, a clearance portion is formed, which is a gap into which a part of the plastically deformed steel plate 23 enters, due to the recess B3 of the other plate B when viewed from the stacking direction.

In the rotor core holding process S2, while the other plate B and the steel plate 23 are in contact with each other, the steel plate 23 of the rotor core 21 is plastically deformed toward the magnet insertion hole 21b by crimping. The inner insertion hole inner surface 21c contacts the magnet 22 and presses the magnet 22 against the outer insertion hole inner surface 21d. The portion of the steel plate 23 that overlaps with the recess B3 as viewed from the stacking direction is not pressurized by the other plate B and can be plastically deformed outward in the stacking direction. Therefore, when the inner insertion hole inner surface 21c contacts the magnet 22 and becomes difficult to plastically deform toward the magnet 22, at least a part of the portion of the steel plate 23 that overlaps with the recess B3 as viewed from the stacking direction is plastically deformed toward the recess B3. In other words, the force applied to the steel plate 23 by crimping is dispersed into a force that plastically deforms the steel plate 23 toward the magnet 22 and a force that plastically deforms the steel plate 23 toward the recess B3. Therefore, in the crimping process S3, a portion of the steel plate 23 is plastically deformed toward the recess B3, so that when the magnet 22 is fixed to the rotor core 21 by crimping, no excessive stress is generated in the portion of the magnet 22 where the steel plate 23 contacts. Therefore, the rotor core 21 can crimp the magnet 22 with a stronger force than when the force applied to the magnet 22 is not distributed in the stacking direction. This allows the force required to hold the magnet 22 to be increased within a range where no excessive stress is generated.

In addition, in the rotor core holding process S2, the recess B3 of the other plate B is located as a clearance in the stacking direction of the rotor core 21. In addition, in the crimping process S3, a part of the crimped steel plate 23 is plastically deformed toward the recess B3, which is a clearance located between the crimped surface 23b and the other plate B. For this reason, the rotor core 21 does not need to have a clearance around the magnet insertion hole 21b. Therefore, the part plastically deformed by crimping is unlikely to elastically deform in the radial direction, for example, even if a radial external force is applied to the magnet 22. In other words, a rotor 2 that does not have a clearance around the magnet insertion hole 21b is unlikely to lose the force that holds the magnet 22 by crimping. Furthermore, since the rotor 2 does not have a space that is a clearance around the magnet 22, deterioration of the magnetic properties can be suppressed.

Furthermore, in the above-mentioned configuration, in the crimping process S3, the rotor core 21 is crimped while being further pressurized in the stacking direction by one plate B and the other plate B. Therefore, since the stacked steel plates 23 are crimped in a state of close contact, the force input from the crimping pin A is transmitted to the crimping surface 23b without escaping in the stacking direction. Therefore, the magnet 22 can be more securely held in the magnet insertion hole 21b compared to when no further pressure is applied in the stacking direction by a pair of plates B during crimping.

In addition, in the above-mentioned configuration, the recess B3 extends from the pin insertion hole B1 to the magnet insertion hole 21b when viewed from the stacking direction. Therefore, the portion that has been plastically deformed between the pin insertion hole B1 and the magnet insertion hole 21b by crimping can be released into the recess B3.

The rotor manufacturing method described above and the rotor manufactured by the manufacturing method can release excess force applied to the magnet 22 and stably hold the magnet 22 within the magnet insertion hole 21b.

(Embodiment 2)
(Rotor Configuration)
Next, a rotor 102 according to a second embodiment of the present invention will be described. The rotor 102 has a rotor core 121 and magnets 22. In the rotor 102, the shape of the steel plates 123 located at both ends of the rotor core 121 in the stacking direction is different from the shape of the steel plates 23 located at both ends of the rotor core 21 in the stacking direction of the first embodiment. Only the configuration different from the first embodiment will be described below, and the same reference numerals will be used to denote the same configuration as the first embodiment, and description thereof will be omitted.

FIG. 8 is a perspective view showing the schematic configuration of the rotor 102 according to the second embodiment. As shown in FIG. 8, the rotor core 121 has a predetermined shape and includes a plurality of steel plates 23 and steel plates 123 stacked in the thickness direction. The steel plates 123 are stacked on both ends in the stacking direction of the plurality of steel plates 23 stacked in the thickness direction.

The steel plate 123 has an opening 123a that constitutes part of the magnet insertion hole 21b. A part of the inner peripheral surface of the opening 123a that constitutes the inner insertion hole inner surface 21c has two notches cut out radially inward. Thus, at both ends of the rotor core 121 in the stacking direction, there are two recesses 24 formed by the notches of the steel plate 123 and the steel plate 23 adjacent to the steel plate 123. The two recesses 24 extend radially inward from each magnet insertion hole 21b.

Figure 9 is a cross-sectional view of line IX-IX in Figure 8. As shown in Figure 9, the depth of the recess 24 in the stacking direction is the thickness of one steel plate 123. The surface of the steel plate 23, which is the bottom surface of the recess 24, is crimped in the stacking direction by crimping pin A. In other words, the bottom surface of the recess 24 is the crimped surface 23b.

The rotor core 121 has a portion of the inner insertion hole inner surface 21c plastically deformed inwardly of the magnet insertion hole 21b due to the crimping of the crimping surface 23b. In other words, the steel plate 23 crimped in the stacking direction by the crimping pin A has the inner peripheral surface of the opening 23a, which is the inner insertion hole inner surface 21c, protruding toward the magnet 22.

A portion of the inner insertion hole inner surface 21c that protrudes toward the magnet 22 is in contact with the magnet 22 in the magnet insertion hole 21b. In addition, a portion of the steel plate 23 between the position where the crimping pin A contacts and the magnet insertion hole 21b is plastically deformed outward in the stacking direction from the crimping surface 23b. In other words, the portion that has been plastically deformed outward in the stacking direction due to crimping protrudes outward in the stacking direction from the stacking direction position of the crimped steel plate 23 in the rotor core 121. In addition, the portion of the steel plate 23 that has been plastically deformed outward in the stacking direction is located within the recess 24.

A portion of the inner insertion hole inner surface 21c that has been plastically deformed by crimping is pressed against the magnet 22 in the magnet insertion hole 21b. The magnet 22 is pressed toward the outer insertion hole inner surface 21d by a portion of the inner insertion hole inner surface 21c. Therefore, the magnet 22 is held in the magnet insertion hole 21b in a state where it is pressed against the outer insertion hole inner surface 21d by a portion of the inner insertion hole inner surface 21c that has been plastically deformed by crimping.

In the above-mentioned configuration, the rotor core 121 has a crimped surface 23b located on the bottom surface of a recess 24 that is connected to the magnet insertion hole 21b at at least one end in the stacking direction. A part of the crimped steel plate 23 that protrudes in the stacking direction beyond the crimped surface 23b is located within the recess 24. This prevents the size of the rotor 102 in the stacking direction from increasing. In addition, the force applied to the magnet 22 by crimping is dispersed by plastic deformation in the stacking direction. This prevents damage to the magnet 22. In addition, when the magnet 22 is fixed to the rotor core 121 by crimping, excessive stress is not generated in the part of the magnet 22 where the steel plate 23 contacts. Therefore, the rotor core 121 can crimp the magnet 22 with a stronger force than when the force applied to the magnet 22 is not dispersed in the stacking direction. This allows the force required to hold the magnet 22 to be increased within a range where excessive stress is not generated.

In addition, in the above-mentioned configuration, the crimping surface 23b is located on the second or subsequent steel plate 23 from the end in the stacking direction among the multiple steel plates 23 and steel plates 123 that constitute the rotor core 121. Therefore, the portion that protrudes in the stacking direction from the crimping surface 23b does not protrude in the stacking direction from the end of the rotor core 121 in the stacking direction. Therefore, by crimping the rotor core 121 in the stacking direction, it is possible to prevent the dimension of the rotor 102 in the stacking direction from increasing. In addition, by cutting out the steel plate 123 at the end in the stacking direction among the stacked steel plates 23 and steel plates 123 and making the second steel plate 23 from the end in the stacking direction of the rotor core 121 the crimping surface 23b, it is possible to suppress the deterioration of the magnetic properties of the rotor core 121. In addition, the magnet 22 is held in the magnet insertion hole 21b with a stable holding force without excessive force being applied.

This prevents the magnets 22 from shifting in the stacking direction due to vibrations caused by the rotational motion of the rotor 102.

(Rotor manufacturing method)
Next, a method for manufacturing the rotor 102 will be described, in which the rotor 102 is manufactured from the rotor core 121, which is made up of a plurality of steel plates 23 and steel plates 123 stacked in the thickness direction, and the magnets 22. Only configurations different from the first embodiment will be described below, and configurations that are the same as those in the first embodiment will be given the same reference numerals and will not be described. Also, only the crimping in one direction in the stacking direction will be described below.

The manufacturing method of the rotor 102 according to the second embodiment will be described with reference to FIG. 4. As shown in FIG. 4, the manufacturing method of the rotor 102 according to the second embodiment includes a magnet insertion process S1, a rotor core holding process S2, and a crimping process S3. The manufacturing method of the rotor 102 is performed in the order of the magnet insertion process S1, the rotor core holding process S2, and the crimping process S3. In the manufacturing method of the rotor 102 according to the second embodiment, a pair of plates B10 is used instead of the pair of plates B used in the manufacturing method of the rotor 2 according to the first embodiment. The pair of plates B10 has a shape that does not have the recesses B3 in the pair of plates B.

FIG. 10 is a diagram showing an example of the magnet insertion process S1 according to the second embodiment. As shown in FIG. 10, the magnet insertion process S1 is a process of inserting the magnet 22 into the magnet insertion hole 21b of the rotor core 121.

In the magnet insertion process S1, the recess 24 of the rotor core 121 placed on one plate B10 overlaps with the pin insertion hole B1 of the other plate B10 when viewed from the stacking direction. The magnet 22 is inserted into the magnet insertion hole 21b to a position where one end in the longitudinal direction contacts the plate B10. This keeps the magnet 22 in the magnet insertion hole 21b.

FIG. 11 is a diagram showing an example of the rotor core holding process S2 according to embodiment 2. As shown in FIG. 11, the rotor core holding process S2 is a process in which the rotor core 121 with the magnets 22 inserted therein is pressurized in the stacking direction by a pair of plates B10.

In the rotor core holding step S2, the contact surface B2 of the other plate B10 is brought into contact with the end face in the other stacking direction of the rotor core 121 placed on one plate B10 by a driving device (not shown). Each pin insertion hole B1 of the pair of plates B10 overlaps with a recess 24 of the rotor core 121 from the stacking direction when the plate B10 and the steel plate 123 are in contact. Therefore, the recess 24 extends from the pin insertion hole B1 toward the magnet insertion hole 21b when viewed from the stacking direction. The recess 24 forms a gap between the one plate B10 and the other plate B10 and the steel plate 123. In other words, the recess 24 is formed as a clearance into which the steel plate 23 plastically deformed in the stacking direction enters by the crimping step S3 described later.

Next, while the pair of plates B10 and the rotor core 121 are in contact with each other, the pair of plates B10 pressurize the rotor core 121 in the stacking direction. As a result, the rotor core 121 is held by the plates B10 located at both end faces in the stacking direction.

FIG. 12 is a diagram showing an example of the crimping process S3 according to the second embodiment. As shown in FIG. 12, the crimping process S3 is a process in which the rotor core 121 is crimped in the stacking direction by a crimping pin A inserted into the pin insertion hole B1 to hold the magnet 22 in the magnet insertion hole 21b. Below, only the crimping in the other stacking direction will be described.

In the crimping process S3, the rotor core 121 is further compressed in the stacking direction by the pair of plates B10. With the rotor core 121 further compressed in the stacking direction by the pair of plates B10, a crimping pin A is inserted in the stacking direction from the pin insertion hole B1 of the other plate B10 that crimps the rotor core 121.

The crimping pin A comes into contact with the crimping surface 23b on the bottom surface of the recess 24 of the rotor core 121. The crimping pin A is pressed in the stacking direction by a driving device (not shown) radially inward from the magnet insertion hole 21b in the steel plate 23 and near the magnet insertion hole 21b. As a result, the steel plate 23 adjacent to the steel plate 123 is crimped in the stacking direction by the crimping pin A.

A portion of the inner surface 21c of the inner insertion hole of the rotor core 121 is plastically deformed inwardly in the magnet insertion hole 21b by crimping. That is, in the steel plate 23 crimped in the stacking direction by the crimping pin A, at least a portion of the recess 24 that is not in contact with the other plate B10 is plastically deformed outwardly in the stacking direction. The portion that is plastically deformed outwardly in the stacking direction is located within the recess 24.

The steel plate 23, which has been plastically deformed by crimping with the crimping pin A, has a portion that has been plastically deformed toward the inside of the magnet insertion hole 21b that comes into contact with the magnet 22, pressing the magnet 22 against the inner surface of the outer insertion hole 21d. As a result, the magnet 22 is held in the magnet insertion hole 21b by the part of the steel plate 23 that has been plastically deformed by crimping and the inner surface of the outer insertion hole 21d.

In the manufacturing method configured as described above, the escape portion is a recess 24 located at the end of the rotor core 121 in the lamination direction and recessed in the lamination direction. The bottom surface of the recess 24, which is the crimped surface 23b plastically deformed in the lamination direction in the crimping process S30, does not protrude in the lamination direction beyond the end surface of the rotor core 121 in the lamination direction. Therefore, by crimping the rotor core 121 in the lamination direction, it is possible to prevent the dimension of the rotor 102 in the lamination direction from increasing. Also, in the crimping process S30, a part of the steel plate 23 that is plastically deformed by crimping and pressed against the magnet 22 deforms toward the recess 24 located between the crimped surface 23b of the rotor core 121 and the plate B10. In other words, the force applied to the magnet 22 by the plastically deformed steel plate 23 is dispersed by plastic deformation in the lamination direction. Therefore, damage to the magnet 22 can be prevented.

In addition, in the above-mentioned configuration, the crimping surface 23b is located on the second or subsequent steel plate 23 from the end of the stacking direction among the multiple steel plates 23 and steel plates 123. In other words, in the rotor core 121, the second or subsequent steel plate 23 from the end of the stacking direction is crimped. As a result, the rotor core 121 is formed with a recess 24 that is deeper than the amount of plastic deformation in the stacking direction due to crimping. The steel plate 23 that undergoes plastic deformation in the stacking direction in the crimping process S30 is located in the recess 24. Therefore, even if the inside of the recess 24 undergoes plastic deformation in the stacking direction due to crimping, the rotor core 121 can prevent the dimension of the rotor 102 in the stacking direction from increasing. In addition, the rotor core 121 has a recess 24 in which the steel plate 123 at the end of the stacking direction is cut out, thereby minimizing the deterioration of the magnetic properties. In addition, in the crimping process S30, the force applied to the magnet 22 by crimping is dispersed by plastic deformation in the stacking direction. Therefore, when the magnet 22 is fixed to the rotor core 121 by crimping, excessive stress is not generated in the part of the magnet 22 where the steel plate 123 contacts. Therefore, the rotor core 121 can crimp the magnet 22 with a stronger force than when the force applied to the magnet 22 is not distributed in the stacking direction. This allows the force required to hold the magnet 22 to be increased within a range where excessive stress is not generated.

This allows excess force applied to the magnet 22 to escape, allowing the magnet 22 to be held stably within the magnet insertion hole 21b.

Other embodiments
Although the embodiment of the present invention has been described above, the above-mentioned embodiment is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-mentioned embodiment, and it is possible to carry out the above-mentioned embodiment by appropriately modifying it within the scope of the gist of the present invention.

In the above-mentioned embodiment 1, the configuration shown in FIG. 1 has been described as the configuration of the motor 1. However, the motor may have a configuration other than that shown in FIG. 1. In other words, the motor may have a configuration other than that shown in FIG. 1 as long as it is an IPM motor.

In each of the above-described embodiments, one of the pair of inner surfaces that form the long sides of the magnet insertion hole 21b when viewed from the axial direction is located radially inward of the rotor core 21. The other of the pair of inner surfaces is located radially outward of the rotor core 21. However, the pair of inner surfaces that form the long sides of the magnet insertion hole do not have to be located radially inward and radially outward.

In the above-mentioned embodiment 1, the crimping surface 23b is located radially inward from the magnet insertion hole 21b, and is crimped at two locations near the magnet insertion hole 21b. However, the crimping of the crimping surface only needs to be located around the magnet insertion hole. Also, the number of crimps may be one location, or three or more locations.

In the above-mentioned embodiment 1, the pair of plates B have recesses B3 recessed from their respective contact surfaces B2 in the thickness direction to a depth approximately equal to the thickness of the steel plate 23. Furthermore, the two recesses B3 are located radially inward from the magnet insertion holes 21b when the pair of plates B and the rotor core 21 are in contact. However, it is sufficient that the recesses are located around the magnet insertion holes when the pair of plates and the rotor core are in contact. Furthermore, there may be one recess around each magnet insertion hole, or three or more recesses.

In each of the above-described embodiments, in the magnet insertion step S1, the rotor core 21, 121 is placed on the plate B, B10. However, in the magnet insertion step, the rotor core may be placed on a plate that does not have a pin insertion hole. In this case, in the rotor core holding step, the rotor core is pressurized by the plate from one end face in the stacking direction of the rotor core. Also, in the crimping step, one end of the rotor core in the stacking direction is crimped by a crimping pin.

In each of the above-described embodiments, in the crimping step S3, the rotor core 21, 121 is crimped in the stacking direction by the crimping pin A while being further pressurized in the stacking direction by the plates B, B10. However, in the crimping step, the rotor core may be crimped in the stacking direction by the crimping pin without being further pressurized in the stacking direction by the plates.

In each of the above-described embodiments, the clearance extends from the pin insertion hole B1 toward the magnet insertion hole 21b when viewed from the stacking direction. However, it is sufficient that the clearance is formed between the pin insertion hole and the magnet insertion hole when viewed from the stacking direction.

In the above-mentioned second embodiment, the steel plates 123 located at both ends of the rotor core 121 in the stacking direction have cutouts. The cutouts are cut out radially inward from a part of the inner circumferential surface of the opening 123a that constitutes the inner insertion hole inner surface 21c. However, the cutouts may also be through holes that penetrate the steel plates located at both ends of the rotor core in the stacking direction in the thickness direction and into which a crimping pin can be inserted. In addition, it is sufficient that the through holes are formed between the pin insertion hole and the magnet insertion hole when viewed from the stacking direction.

In the above-mentioned second embodiment, the steel plate 123 having the notch is laminated on both stacking direction ends of the rotor core 121. However, the steel plate having the notch may be laminated on one stacking direction end of the rotor core. In other words, the rotor core may have a recess formed only on one stacking direction end of the rotor core.

In the above-mentioned second embodiment, the depth in the stacking direction of the recess 24 formed in the rotor core 121 is the same as the thickness of one steel plate 123. However, the depth in the stacking direction of the recess formed in the rotor core may be shallower than the thickness of one steel plate, or deeper than the thickness of one steel plate. In other words, the rotor core may have multiple steel plates with notches at both ends in the stacking direction. Furthermore, the steel plates with notches may have a shape with a portion recessed in the stacking direction.

In the above-mentioned second embodiment, the recesses 24 are located radially inward from the magnet insertion holes 21b in the rotor core 121. Furthermore, the two recesses 24 are located radially inward from the magnet insertion holes 21b. However, it is sufficient that the recesses are located around the magnet insertion holes. Furthermore, there may be one recess around each magnet insertion hole, or three or more recesses.

(1)
A manufacturing method of a rotor having a plurality of steel plates laminated in a thickness direction and magnets penetrating the plurality of steel plates in a lamination direction, the magnets located in the magnet insertion holes being held in the rotor core by crimping the rotor core. The manufacturing method of the rotor includes a magnet insertion step of inserting the magnets into the magnet insertion holes, a rotor core holding step of covering at least a part of an end face in the lamination direction of the rotor core into which the magnets are inserted from the lamination direction with a plate having a pin insertion hole into which a crimping pin for crimping the rotor core can be inserted, and applying pressure in the lamination direction to at least one end face in the lamination direction of the rotor core with the plate, and a crimping step of crimping the rotor core in the lamination direction with the crimping pin inserted into the pin insertion hole to hold the magnets in the magnet insertion hole. In the rotor core holding step, the rotor core is held in a state in which a clearance portion into which the plastically deformed steel plate enters is provided between the crimping surface in contact with the crimping pin and the plate. In the crimping step, the rotor core held by the plate is crimped in the lamination direction with the crimping pin.

(2)
In the rotor manufacturing method described in (1), the relief portion is a recess located at at least one end of the rotor core in the stacking direction and recessed in the stacking direction. In the crimping step, a crimping pin is inserted into the pin insertion hole to crimp the rotor core in the stacking direction, with a bottom surface of the recess serving as the crimping surface.

(3)
In the method for manufacturing a rotor according to (1) or (2), the crimping surface is located on one of the plurality of steel plates other than the steel plate that is in contact with the plate.

(4)
In the method for manufacturing a rotor described in (1), the relief portion is a recess located on a contact surface of the plate that contacts the rotor core and recessed outward in a lamination direction from the contact surface. In the crimping step, at least one end of the rotor core in the lamination direction is crimped in the lamination direction as the crimp surface by a crimping pin inserted into the pin insertion hole.

(5)
In the method for manufacturing a rotor described in any one of (1) to (4), in the crimping step, the rotor core is crimped in a state in which the rotor core is further pressurized in a stacking direction by the plate.

(6)
In the method for manufacturing a rotor described in any one of (1) to (5), the recess extends from the pin insertion hole to the magnet insertion hole when viewed in the stacking direction.

(7)
The rotor includes a rotor core having a plurality of steel plates laminated in the thickness direction and magnet insertion holes penetrating the plurality of steel plates in the lamination direction, and magnets to be inserted into the magnet insertion holes, the magnets being held within the magnet insertion holes of the rotor core. The rotor core has a portion that is in contact with the magnet by crimping and protrudes in the lamination direction beyond a crimping surface of the rotor core that is crimped.

(8)
(7) A rotor according to the present invention, wherein the rotor core has a recess connected to the magnet insertion hole at at least one end in the stacking direction, and a bottom surface of the recess is the crimping surface.

(9)
In the rotor according to (7) or (8), the crimping surface is located on a steel plate other than the steel plate located at the end portion in the stacking direction of the at least one of the plurality of steel plates.

(10)
An IPM motor including the rotor according to any one of (7) to (9) above, and a stator having a stator coil and a stator core.

The present invention can be used for a rotor manufacturing method, a rotor, and an IPM motor having the rotor.

1 Motor (IPM motor)
Reference Signs List 2, 102 rotor 3 stator 4 housing 20 shaft 21, 121 rotor core 21a through hole 21b magnet insertion hole 21c inner surface of inner insertion hole 21d inner surface of outer insertion hole 22 magnet 23, 123 steel plate 23a, 123a opening 23b crimped surface 23c crimp mark 24, B3 recess 31 stator core 32 stator coil S1 magnet insertion process S2 rotor core holding process S3 crimping process A crimp pin B, B10 plate B1 pin insertion hole B2 contact surface P central axis

Claims (10)

A manufacturing method of a rotor having a plurality of steel plates laminated in a thickness direction and magnet insertion holes penetrating the plurality of steel plates in a lamination direction, the rotor core being crimped to hold magnets located in the magnet insertion holes, the manufacturing method comprising the steps of:
a magnet insertion step of inserting the magnet into the magnet insertion hole;
a rotor core holding process in which at least a portion of an end face in the lamination direction of the rotor core, into which the magnets are inserted, is covered from the lamination direction by a plate having a pin insertion hole into which a crimping pin for crimping the rotor core can be inserted, and the plate applies pressure in the lamination direction to at least one end face in the lamination direction of the rotor core;
a crimping step of crimping the rotor core in a lamination direction by a crimping pin inserted into the pin insertion hole to hold the magnet in the magnet insertion hole;
having
In the rotor core holding step,
holding the rotor core in a state in which a relief portion into which the plastically deformed steel plate enters is provided between the crimping surface with which the crimping pin contacts and the plate;
In the crimping process,
the rotor core held by the plate is crimped in the lamination direction by the crimping pin. 2. The method of claim 1, further comprising the steps of:
The relief portion is
a recess located at at least one end of the rotor core in the lamination direction and recessed in the lamination direction,
In the crimping step, a crimp pin is inserted into the pin insertion hole to crimp in the stacking direction, with the bottom surface of the recess serving as the crimping surface. 3. The method for manufacturing a rotor according to claim 1, further comprising the steps of:
The crimping surface is
A method for manufacturing a rotor, wherein the plate is located on one of the plurality of steel plates other than the steel plate with which the plate is in contact. 2. The method of claim 1, further comprising the steps of:
The relief portion is
a recess located on a contact surface of the plate that contacts the rotor core and recessed outward in a lamination direction from the contact surface,
In the crimping step, a crimping pin is inserted into the pin insertion hole to crimp at least one lamination direction end of the rotor core in the lamination direction as the crimping surface. 2. The method of claim 1, further comprising the steps of:
In the crimping step, the rotor core is crimped while being further pressurized in a stacking direction by the plate. 2. The method of claim 1, further comprising the steps of:
The relief portion is
A manufacturing method of a rotor, the manufacturing method including: when viewed in the stacking direction, the pin insertion hole extends to the magnet insertion hole. a rotor core having a plurality of steel plates laminated in a thickness direction and magnet insertion holes penetrating the plurality of steel plates in the lamination direction;
A magnet to be inserted into the magnet insertion hole;
having
A rotor in which the magnet is held in the magnet insertion hole of the rotor core,
The rotor core is
a portion that is in contact with the magnet by crimping protrudes in a lamination direction beyond a crimped surface of the rotor core. 8. A rotor according to claim 7,
The rotor core is
At least one end in the stacking direction has a recess connected to the magnet insertion hole,
A rotor, wherein a bottom surface of the recess is the crimping surface. 8. A rotor according to claim 7,
The crimping surface is
a rotor, the rotor being located on a steel plate other than the steel plate located at an end portion in the stacking direction of the at least one of the plurality of steel plates. A rotor according to claim 7;
and a stator having a stator coil and a stator core.

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