Rotor and method for manufacturing the rotor

Abstract

To provide a rotor capable of suppressing deformation of a rotor core caused by an increase in the pressure of a resin applied to a magnet accommodation hole when the resin is injected.SOLUTION: A rotor 100 includes a rotor core 10 including a plurality of magnet housing holes 2 extending along the axial direction and circumferentially spaced apart from each other, a permanent magnet 1 housed in each of the plurality of magnet housing holes 2, and a resin portion 20 including a filling portion 21 formed by filling resin into each of the plurality of magnet housing holes 2. The resin portion 20 is provided at a position that does not overlap the magnet housing hole 2 in the axial direction, and includes a gate trace portion 22a corresponding to a resin injection port 31 when the resin portion 20 is molded.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotor and a manufacturing method of a rotor, and more particularly to a rotor including permanent magnets housed in magnet housing holes of a rotor core and a manufacturing method of a rotor. [Background technology]

[0002] 2. Description of the Related Art A rotor including permanent magnets housed in magnet housing holes of a rotor core and a method for manufacturing the rotor are known in the art (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses a rotor including a rotor core with multiple permanent magnets built in. The permanent magnets are accommodated in slots (magnet accommodating holes) provided in the rotor core. The permanent magnets are fixed in the slots by a filling resin that fills the slots.

[0004] In the above-mentioned Patent Document 1, the filling resin is filled into the slots (magnet accommodating holes) using a filling device. Specifically, the lower die of the filling device includes a pod that opens at a position corresponding to the slot of the rotor core. The filling resin is accommodated inside the pod. A plunger is inserted into the pod from below. The filling resin in the pod is filled into the slots by moving the plunger toward the rotor core. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-67140 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, in the rotor described in Patent Document 1, the filling resin of the pod that opens directly below the slots (magnet accommodating holes) is filled into the slots. That is, the filling resin injected from the pod is injected directly (through a linear path) into the slots. This may cause the pressure of the resin on the slots to increase. In this case, the rotor core may deform. Therefore, it is desirable to suppress deformation of the rotor core caused by the increase in pressure of the resin on the magnet accommodating holes when the resin is injected.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a rotor and a method for manufacturing a rotor that can suppress deformation of the rotor core caused by increased resin pressure applied to the magnet accommodating hole when the resin is injected. [Means for solving the problem]

[0008] In order to achieve the above object, a rotor according to a first aspect of the present invention includes: a rotor core including a plurality of magnet accommodating holes that are provided so as to extend along an axial direction and that are circumferentially spaced apart from one another; a permanent magnet accommodated in each of the plurality of magnet accommodating holes; and a resin portion including a filled portion formed by filling each of the plurality of magnet accommodating holes with resin, the resin portion being provided at a position that does not overlap with the magnet accommodating holes in the axial direction. Ta Including the gate mark corresponding to the resin injection port during molding of the resin part. The gate marks are provided radially inward of the regions between the magnet accommodating holes adjacent to each other in the circumferential direction of the rotor core. The filled portion refers to a resin portion provided in the range from one end to the other end of the rotor core in the axial direction.

[0009] In the rotor according to the first aspect of the present invention, as described above, the resin portion includes a gate mark portion provided at a position that does not overlap with the magnet accommodating hole in the axial direction. That is, resin is injected with the resin injection port positioned at a position that does not overlap with the magnet accommodating hole in the axial direction. This makes it possible to prevent the resin injected from the injection port from being injected directly (through a linear path) into the magnet accommodating hole, compared to when resin is injected with the resin injection port positioned at a position that overlaps with the magnet accommodating hole in the axial direction. As a result, the pressure of the resin applied to the magnet accommodating hole can be reduced. This makes it possible to prevent the rotor core from being deformed due to the increased pressure of the resin applied to the magnet accommodating hole when the resin is injected.

[0010] In the rotor according to the above aspect, preferably, the resin portion includes a connection portion formed of resin that connects the filled portions filled in the magnet accommodating holes adjacent to each other in the circumferential direction of the rotor core at a first end face on one axial side of the rotor core, and the gate mark portion is provided at an end portion on one axial side of the connection portion at a circumferential position corresponding to a position between the magnet accommodating holes adjacent to each other in the circumferential direction. Note that the connection portion refers to a portion of the resin portion provided axially outside the magnet accommodating holes. In other words, the connection portion does not include the resin accommodated in the magnet accommodating holes.

[0011] With this configuration, the resin injected from the injection port is dispersed into adjacent magnet accommodating holes in the circumferential direction, thereby more reliably preventing deformation of the rotor core due to increased resin pressure on the magnet accommodating holes when the resin is injected.

[0012] In a rotor in which the resin part includes a connection part, the connection part is preferably arranged so as to cover parts other than the magnet hole outer ends, without covering at least a portion of the magnet hole outer ends, which are the radially outer ends, of each of the magnet accommodating holes adjacent to each other in the circumferential direction, when viewed from one side in the axial direction.

[0013] Here, at least a part of the magnet accommodating hole that is not covered by the connection part is blocked from one axial side by the upper mold that injects the resin during resin molding. As a result, during resin molding, the part of the upper mold that is provided to block the at least part can suppress the resin in the upper mold from being directly injected into the at least part of the magnet accommodating hole. As a result, it is possible to suppress the at least part of the magnet accommodating hole from being deformed by the pressure of the resin. In addition, when the magnet accommodating hole is disposed in a radially outer part of the rotor core, the part radially outer than the magnet hole outer end has a relatively small radial thickness and therefore a relatively small mechanical strength. Therefore, by the connection part not covering at least a part of the magnet hole outer end of the magnet accommodating hole, the pressure of the resin applied to the part of the rotor core that has a relatively small mechanical strength can be reduced.

[0014] In a rotor in which the resin portion includes a connection portion, preferably, the axial thickness of the filling portion within the magnet accommodating hole that is located on one axial side of the axial end of the permanent magnet is smaller than the axial thickness of the connection portion that is located axially outside the magnet accommodating hole.

[0015] With this configuration, the volume of the filling portion in the magnet accommodating hole can be made smaller than when the axial thickness of the portion of the filling portion located on one axial side of the axial end of the permanent magnet is equal to or greater than the axial thickness of the connection portion located axially outside the magnet accommodating hole. As a result, the amount of resin injected into the space in the magnet accommodating hole corresponding to the portion of the filling portion can be reduced, and the pressure of the resin applied to the portion of the rotor core corresponding to the space in the magnet accommodating hole can be reduced.

[0016] A manufacturing method of a rotor in a second aspect of the present invention is a manufacturing method of a rotor including a rotor core including a plurality of magnet accommodating holes provided to extend along the axial direction and spaced apart from one another circumferentially, and a permanent magnet accommodated in each of the plurality of magnet accommodating holes, the manufacturing method including the manufacturing method of a rotor including: a step of arranging an upper mold including a resin injection inlet on one axial side of the rotor core; a step of supporting the permanent magnet with the pin member by bringing the pin member into contact with the permanent magnet accommodated in each of the plurality of magnet accommodating holes from the other axial side; and a step of forming a resin portion including a filling portion filled in each of the plurality of magnet accommodating holes by injecting resin from one axial side with the upper mold while the permanent magnet is supported from the other axial side by the pin member, wherein the step of forming the resin portion includes a step of forming the resin portion by injecting resin with the injection inlet of the upper mold arranged at a position not overlapping with the magnet accommodating holes in the axial direction. The step of forming the resin portion includes the step of injecting resin from an injection port located radially inside a region sandwiched between magnet accommodating holes adjacent to each other in the circumferential direction of the rotor core. .

[0017] In the rotor manufacturing method according to the second aspect of the present invention, as described above, the step of forming the resin portion includes a step of forming the resin portion by injecting resin with the upper mold injection port positioned at a position that does not overlap with the magnet accommodating hole in the axial direction. This makes it possible to prevent the resin injected from the upper mold from being injected directly (through a straight path) into the magnet accommodating hole, compared to the case where the resin is injected with the injection port positioned at a position that overlaps with the magnet accommodating hole in the axial direction. As a result, the pressure of the resin on the magnet accommodating hole can be reduced. This makes it possible to provide a rotor manufacturing method that can prevent the rotor core from being deformed due to the increased pressure of the resin on the magnet accommodating hole when the resin is injected.

[0018] Furthermore, the resin is injected with the permanent magnet supported by the pin member from the other axial side. This allows the position of the permanent magnet to be easily adjusted by adjusting the position of the pin member, so that the space on one axial side of the permanent magnet in the magnet accommodating hole can be easily reduced. As a result, the volume of the resin injected into the space can be easily reduced, so that the pressure of the resin applied to the portion of the rotor core corresponding to the one axial side of the permanent magnet can be reduced. As a result, deformation of the rotor core can be easily suppressed.

[0019] In the rotor and the manufacturing method of the rotor according to the above aspect, the following configuration is also possible.

[0020] (Additional note 1) That is, in a rotor in which the resin part includes a connection part, the gate mark portion is preferably provided at a circumferential position at one axial end of the connection part corresponding to the centers of magnet accommodating holes adjacent to each other in the circumferential direction.

[0021] By configuring in this manner, the distance between each of the magnet accommodating holes adjacent to each other in the circumferential direction and the injection port can be made equal, thereby making it possible to equalize the pressure of the resin applied to each of the magnet accommodating holes adjacent to each other in the circumferential direction.

[0022] (Additional note 2) In the rotor according to the aforementioned aspect, the gate mark portion is preferably provided radially inward with respect to a region sandwiched between circumferentially adjacent magnet accommodating holes.

[0023] With this configuration, the distance between the gate mark (resin injection port) and the magnet accommodating hole can be made larger than when the gate mark is provided in an area sandwiched between the magnet accommodating holes. As a result, the pressure of the resin on the magnet accommodating hole can be further reduced. Also, when the magnet accommodating hole is provided on the radial outside of the rotor core, the above distance can be easily increased.

[0024] (Additional note 3) In a rotor in which the connection portion covers a portion other than the outer end of the magnet hole, preferably, at least a portion of the outer end of the magnet hole that is not covered by the connection portion includes a portion of the magnetic gap portion provided in the magnet accommodating hole that has the smallest distance from the outer edge portion of the rotor core.

[0025] The portion of the rotor core between the outer edge of the rotor core and the portion of the magnetic gap where the distance from the outer edge of the rotor core is the smallest is the portion near the outer edge of the rotor core that has the weakest mechanical strength. Therefore, reducing the pressure of the resin applied to the portion where the distance is the smallest is particularly effective in suppressing deformation of the rotor core.

[0026] (Additional note 4) In the rotor according to the above aspect, the rotor core preferably includes a positioning portion that is arranged on one axial side of the rotor core when molding the resin portion, engages with an upper mold including a resin injection port, and positions a gate mark portion corresponding to the injection port.

[0027] By configuring in this manner, the position of the gate mark (resin injection port) relative to the magnet accommodating hole can be adjusted with precision, thereby enabling the pressure of the resin applied to the magnet accommodating hole when the resin is injected to be controlled with precision.

[0028] (Additional note 5) In the manufacturing method of a rotor according to the above aspect, the step of supporting the permanent magnet preferably includes a step of supporting the permanent magnet from below with a pin member, and the step of forming the resin part preferably includes a step of forming the resin part by injecting resin from above.

[0029] For example, when a permanent magnet is supported from below by a protruding portion of an electromagnetic steel plate protruding laterally into the magnet accommodating portion, and resin is injected from below into the magnet accommodating hole while a pin member is used from above to restrict the upward movement of the permanent magnet, it is necessary to provide a certain gap between the pin member and the permanent magnet so that the pin member does not apply a pressing force to the protruding portion of the electromagnetic steel plate supporting the permanent magnet. In this case, the axial position of the permanent magnet may change between the electromagnetic steel plate supporting the permanent magnet and the pin member, so that the position of the permanent magnet is not constant. In contrast, by supporting the permanent magnet from below with the pin member, the axial position of the permanent magnet can be constant because resin is injected from above with the pin member positioned in the axial direction. As a result, the performance of the rotor can be constant. [Brief description of the drawings]

[0030] [Figure 1] FIG. 2 is a plan view of a rotor according to an embodiment, as viewed from the Z1 side. [Diagram 2] FIG. 2 is a plan view of a rotor according to an embodiment, as viewed from the Z2 side. [Diagram 3] FIG. 2 is a partially enlarged plan view of the vicinity of the gate mark in FIG. [Figure 4] FIG. 2 is a perspective view showing a configuration of a rotor, an upper mold, and a lower mold according to one embodiment. [Diagram 5] 5 is a cross-sectional view taken at a circumferential position where a positioning portion of the rotor core is provided in FIG. 4. FIG. [Figure 6] FIG. 4 is a flow diagram illustrating a method for manufacturing a rotor according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0032] The configuration of a rotor 100 provided in a motor will be described with reference to Figures 1 to 6. The motor is configured as an interior permanent magnet motor (IPM motor) in which a permanent magnet 1, which will be described later, is embedded in the rotor 100. The motor is, for example, an in-vehicle motor.

[0033] In the following description, the axial, radial, and circumferential directions of rotor core 10 are referred to as the Z direction, R direction, and C direction, respectively. One side of the Z direction is referred to as the Z1 direction side, and the other side of the Z direction is referred to as the Z2 direction side. One side of the C direction is referred to as the C1 direction side, and the other side of the C direction is referred to as the C2 direction side. The radially inner side is referred to as the R1 direction side, and the radially outer side is referred to as the R2 direction side.

[0034] As shown in Fig. 1, rotor 100 includes rotor core 10. Rotor core 10 is provided so as to extend along the axial direction (Z direction) and includes a plurality of magnet accommodating holes 2 that are circumferentially spaced apart from one another. Eight magnet accommodating holes 2 are provided at equal angular intervals about rotation center O of rotor core 10. Each of the plurality of magnet accommodating holes 2 is formed so as to extend linearly along the circumferential direction (C direction).

[0035] Rotor core 10 is formed by stacking a plurality of mutually different electromagnetic steel sheets 10a and electromagnetic steel sheets 10b in the axial direction (Z direction). Specifically, rotor core 10 is configured by arranging a plurality of stacked electromagnetic steel sheets 10a on each of the Z1 side and Z2 side of a plurality of stacked electromagnetic steel sheets 10b (see FIG. 5). Details of electromagnetic steel sheets 10a and electromagnetic steel sheets 10b will be described later.

[0036] The rotor 100 includes permanent magnets 1 (see FIG. 5) accommodated in each of a plurality of magnet accommodating holes 2 of a rotor core 10. The magnet accommodating holes 2 are through holes for accommodating the permanent magnets 1 therein.

[0037] The rotor 100 includes a resin portion 20. The resin portion 20 includes a filling portion 21 (see FIG. 5) formed by filling each of the magnet accommodating holes 2 with resin. The resin portion 20 also includes a connection portion 22 formed of resin that connects the filling portions 21 filled in the magnet accommodating holes 2 adjacent to each other in the circumferential direction (C direction) of the rotor core 10 at an end face 11 on one side (Z1 direction side) in the axial direction of the rotor core 10. The filling portion 21 refers to a portion of the resin portion 20 provided in the range from one end (end face 11) to the other end (end face 12) of the rotor core 10 in the axial direction. The connection portion 22 refers to a portion of the resin portion 20 provided on the axial outer side (Z1 direction side) of the magnet accommodating holes 2. That is, the connection portion 22 does not include the resin accommodated in the magnet accommodating holes 2. The end face 11 is an example of a "first end face" in the claims.

[0038] 1, the connection portion 22 is provided on the end face 11 so as to connect the filling portions 21 filled in all (eight) of the magnet accommodating holes 2. That is, the connection portion 22 is formed in a ring shape on the end face 11. The connection portion 22 is provided so as to cover all (eight) of the magnet accommodating holes 2 from one axial side (Z1 direction side). This makes it possible to prevent the resin portion 20 (filling portion 21) from slipping out toward the Z2 direction side.

[0039] As shown in Figure 2, the resin portion 20 includes a connection portion 23 formed of resin that connects the filling portions 21 filled in adjacent magnet accommodating holes 2 in the circumferential direction (C direction) of the rotor core 10 at the end face 12 on the other axial side (Z2 direction side) of the rotor core 10.

[0040] The connection portion 23 is provided on the end face 12 so as to connect the filling portions 21 filled in all (eight) of the magnet accommodating holes 2. That is, the connection portion 23 is formed in a ring shape on the end face 12. The connection portion 23 is provided so as to cover all (eight) of the magnet accommodating holes 2 from the other axial side (Z2 direction side). This makes it possible to prevent the resin portion 20 (filling portion 21) from slipping out in the Z1 direction.

[0041] That is, the connection portion 22 and the connection portion 23 are connected by the eight filling portions 21, and are integrally formed.

[0042] The connection portion 23 is provided with holes 23a corresponding to pin members 50 (described later) used when molding the resin portion 20. The holes 23a are provided so as to extend along the axial direction (Z direction) from an end portion 23b (see FIG. 5) on the Z2 side of the connection portion 23 to an end portion 1b (see FIG. 5) on the Z2 side of the permanent magnet 1. The holes 23a are holes formed by removing (pulling out) the pin members 50 from the connection portion 23 after the connection portion 23 is formed. Two holes 23a are provided for each of the multiple magnet accommodating holes 2 (permanent magnets 1).

[0043] 1, in this embodiment, the resin portion 20 includes a gate mark portion 22a provided at a position that does not overlap with the magnet accommodating hole 2 in the axial direction. The gate mark portion 22a is a portion (protrusion) that corresponds to a resin injection port 31 (see FIG. 4) provided in an upper mold 30 described later when molding the resin portion 20. In other words, the gate mark portion 22a is provided at a position shifted from the circumferential position of the magnet accommodating hole 2 at least in the circumferential direction.

[0044] In detail, the gate mark portion 22a is provided at an end portion 22b (end surface, see FIG. 5) on one axial side of the connection portion 22, at a circumferential position corresponding to a position between the magnet accommodating holes 2 adjacent to each other in the circumferential direction. That is, the gate mark portion 22a is provided at a circumferential position corresponding to the position of the bridge portion 15 that connects the radial outer portion 13 provided on the radial outer side (R2 side) of the magnet accommodating hole 2 in the rotor core 10 and the radial inner portion 14 provided on the radial inner side (R1 side) of the magnet accommodating hole 2 in the rotor core 10. In other words, the gate mark portion 22a is provided at a position overlapping with the bridge portion 15 when viewed in the radial direction. The bridge portion 15 is provided so as to extend along the radial direction.

[0045] 3, the gate mark portion 22a is provided at a circumferential position corresponding to the centers of circumferentially adjacent magnet accommodating holes 2 on the end portion 22b (end face) on one axial side of the connecting portion 22. In other words, when viewed from one axial side (Z1 direction side), the shortest distance D1 between the position where the gate mark portion 22a is provided and the position (range) where one of the two adjacent magnet accommodating holes 2 is provided is equal to the shortest distance D2 between the position where the gate mark portion 22a is provided and the position (range) where the other of the two adjacent magnet accommodating holes 2 is provided.

[0046] Moreover, the gate mark portion 22a is provided radially inward with respect to a region S sandwiched between magnet accommodating holes 2 adjacent to each other in the circumferential direction.

[0047] Here, the connection portion 22 includes a plurality of protrusions 22d provided so as to protrude radially inward from an inner peripheral edge 22c of the connection portion 22, and an annular portion 22e connected to each of the plurality of protrusions 22d on the outer peripheral side of the plurality of protrusions 22d. A part of the gate mark 22a is provided on each of the plurality of protrusions 22d. Specifically, each of the plurality of gate mark portions 22a is provided so as to straddle the protrusion 22d and the annular portion 22e formed in an annular shape. The protrusion 22d has a semicircular shape convex radially inward when viewed from one axial side (Z1 direction side).

[0048] In this embodiment, the connection portion 22 is provided so as to cover the portions other than the magnet hole outer end 2a without covering a part (end 2b described later) of the magnet hole outer end 2a, which is the end on the radially outer side (R2 side) of each of the magnet accommodating holes 2 adjacent to each other in the circumferential direction (C direction), when viewed from one side in the axial direction (Z1 direction). Specifically, the connection portion 22 covers the portions other than the magnet hole outer end 2a, and is provided so as to cover the portions 2c between the ends 2b on both sides in the circumferential direction of the magnet hole outer end 2a without covering the ends 2b on both sides in the circumferential direction. Each of the magnet hole outer end 2a, the end 2b, and the portion 2c means an area within the magnet accommodating hole 2 when viewed from one side in the axial direction.

[0049] At the outer circumferential edge 22f of the connecting portion 22, a portion corresponding to a position between adjacent magnet accommodating holes 2 in the circumferential direction (direction C) is recessed radially inward. This provides a concave portion 22g in the connecting portion 22. The connecting portion 22 is provided so that the concave portion 22g is recessed radially inward, and thus does not cover the ends 2b on both sides of the magnet hole outer end 2a.

[0050] Furthermore, the portion (end 2b) of the magnet hole outer end 2a that is not covered by the connecting portion 22 includes a portion 2e of the magnetic gap 2d provided in the magnet accommodating hole 2 where the distance D3 between the portion and the outer edge portion 16 of the rotor core 10 is minimum. Note that portion 2e refers to a portion of the outer peripheral edge on the radially outer side of the end 2b. Also, the filling portion 21 that fills the portion of the magnet accommodating hole 2 (magnetic gap 2d) that is not covered by the connecting portion 22 is exposed.

[0051] In this embodiment, as shown in FIG. 5, the thickness t1 in the axial direction (Z direction) of the portion 21a of the filling portion 21, which is provided on one axial side of the end 1a on one axial side (Z1 direction side) of the permanent magnet 1 (the axial distance between the end 1a of the permanent magnet 1 and the end face 11 of the rotor core 10, for example, about 0.1 to 0.2 mm) is smaller than the thickness t2 in the axial direction of the connecting portion 22 (for example, about 1 mm). The thickness t1 of the portion 21a is smaller than the thickness t3 in the axial direction of the connecting portion 23 (for example, about 1 mm). The thickness t2 of the connecting portion 22 and the thickness t3 of the connecting portion 23 are equal to each other.

[0052] Furthermore, thickness t1 of portion 21a is smaller than both axial (Z-direction) thickness t4 (e.g., about 0.5 mm) of electromagnetic steel sheet 10a and axial (Z-direction) thickness t5 (e.g., about 0.5 mm) of electromagnetic steel sheet 10b. Thickness t4 of electromagnetic steel sheet 10a and thickness t5 of electromagnetic steel sheet 10b are equal to each other.

[0053] Furthermore, the thickness t6 in the axial direction (Z direction) of portion 21b of filling portion 21, which is provided on the other axial side of end 1b on the other axial side (Z2 direction side) of permanent magnet 1 (the axial distance between end 1b of permanent magnet 1 and end face 12 of rotor core 10, for example about 0.1 to 0.2 mm) is smaller than each of thickness t2 of connecting portion 22, thickness t3 of connecting portion 23, thickness t4 of electromagnetic steel sheet 10a, and thickness t5 of electromagnetic steel sheet 10b. The relationship between the thicknesses t1 to t6 is not limited to the above relationship and can be changed as appropriate.

[0054] As shown in Fig. 1, rotor core 10 includes positioning portion 17a that is disposed on one axial side (Z1 direction side) of rotor core 10 when resin portion 20 is molded, engages with upper mold 30 (see Fig. 4) that includes resin injection port 31, and positions gate mark portion 22a corresponding to injection port 31. Positioning portion 17a is configured as a recess recessed radially outward on inner circumferential edge 17 of rotor core 10. Four positioning portions 17a are provided on inner circumferential edge 17 of rotor core 10 at equal angular intervals (90 degree intervals) centered around center of rotation O of rotor core 10 (see Fig. 1).

[0055] As shown in Fig. 4, the positioning portion 17a is formed by stacking in the Z direction notched portions 17b provided in each of a plurality of electromagnetic steel sheets 10a arranged on top of a plurality of electromagnetic steel sheets 10b. Note that, for simplification, the boundary lines between the electromagnetic steel sheets are not shown in Fig. 4.

[0056] The upper die 30 is provided with an engagement portion 32 that protrudes from a lower surface 30a (see FIG. 5) of the upper die 30 and is engaged with a corresponding positioning portion 17a.

[0057] A method for manufacturing the rotor 100 will be described with reference to FIG. 1 and FIGS.

[0058] First, as shown in Fig. 6, in step S1, a process of forming rotor core 10 is performed. Specifically, rotor core 10 is formed by stacking a plurality of electromagnetic steel sheets 10a (see Fig. 5) and a plurality of electromagnetic steel sheets 10b (see Fig. 5). In more detail, rotor core 10 is formed by stacking a plurality of electromagnetic steel sheets 10b on top of a plurality of electromagnetic steel sheets 10a, and further stacking a plurality of electromagnetic steel sheets 10a on top of a plurality of electromagnetic steel sheets 10b.

[0059] Next, in step S2, a process is performed in which the permanent magnets 1 are arranged in the magnet accommodating holes 2. Specifically, the permanent magnets 1 are arranged (accommodated) in the magnet accommodating holes 2 by inserting the permanent magnets 1 axially into each of the multiple magnet accommodating holes 2.

[0060] Next, in step S3, a process of setting upper die 30, lower die 40, and pin member 50 (see FIG. 5) is performed. Specifically, in step S3, upper die 30 is placed on one axial side (Z1 direction side) of rotor core 10. Specifically, upper die 30 is placed on the upper side of rotor core 10. More specifically, upper die 30 is placed on end surface 11 of rotor core 10 (see FIGS. 4 and 5). At this time, each of four engagement portions 32 of upper die 30 is engaged with a corresponding positioning portion 17a of rotor core 10, thereby positioning injection port 31 of upper die 30.

[0061] In step S3, rotor core 10 is supported from the other axial side (Z2 direction side, lower side) by lower die 40. As a result, rotor core 10 is sandwiched between upper die 30 and lower die 40 in the vertical direction (Z direction).

[0062] Furthermore, in step S3, the pin members 50 are brought into contact with the permanent magnets 1 accommodated in each of the multiple magnet accommodating holes 2 from the other axial side (lower side), thereby supporting the permanent magnets 1 from below by the pin members 50. The pin members 50 abut against the ends 1b of the permanent magnets 1 by penetrating through the holes 40a (see FIG. 5 ) of the lower die 40. The pin members 50 are brought into contact with the permanent magnets 1 through the holes 40a after the rotor core 10 is placed (supported) on the lower die 40. The rotor core 10 may be placed on the lower die 40 with the pin members 50 already placed in the holes 40a of the lower die 40.

[0063] Next, in step S4, a process of forming the resin part 20 is performed. Specifically, in step S4, with the permanent magnet 1 supported from the other axial side (Z2 direction side, lower side) by the pin member 50, resin is injected from one axial side (Z1 direction side, upper side) by the upper die 30 to form the resin part 20 including the filling parts 21, the connecting parts 22, and the connecting parts 23 filled in each of the multiple magnet accommodating holes 2.

[0064] The upper mold 30 is provided with one introduction flow path 33 (see FIG. 4) through which the resin is introduced, a plurality of (eight) branch flow paths 34 (see FIG. 4) branching from the introduction flow path 33 toward each of the plurality of injection ports 31, and a hollow portion 35 (see FIG. 5) having a shape corresponding to the connection portion 22. The eight branch flow paths 34 are provided so as to extend radially from the introduction flow path 33 when viewed from the upper side (Z1 direction side). The resin flowing from the introduction flow path 33 into the corresponding branch flow path 34 is injected into each of the plurality of (eight) magnet accommodating holes 2. As a result, the resin is simultaneously injected into the plurality of (eight) magnet accommodating holes 2 from each injection port 31. Then, after the resin is filled into each of the plurality of magnet accommodating holes 2 and the hollow portion 41 (see FIG. 5) of the lower mold 40 described later, the hollow portion 35 of the upper mold 30 is filled with the resin. The lower portion of the hollow portion 35 is opened to allow the resin to flow downward (to the magnet accommodating hole 2 side).

[0065] The lower die 40 is provided with a hollow portion 41 having a shape corresponding to the connecting portion 23. The resin that has flowed through the magnet accommodating hole 2 flows into the hollow portion 41. The upper portion of the hollow portion 41 is opened to allow the resin to flow in.

[0066] Here, in this embodiment, the step (S4) of forming the resin portion 20 includes a step of forming the resin portion 20 by injecting resin into a position that does not overlap with the magnet accommodating holes 2 in the axial direction. Specifically, the resin is injected into circumferential positions corresponding to the centers of the magnet accommodating holes 2 that are adjacent to each other in the circumferential direction. Thereby, the resin injected from one injection port 31 is dispersed toward each of the two adjacent magnet accommodating holes 2 through the hollow portion 35 of the upper mold 30. As a result, the resin injected from one injection port 31 is injected into the two adjacent magnet accommodating holes 2.

[0067] When the resin is injected, the entire end face 11 of the rotor core 10 is pressed from above (Z1 direction side) by the upper die 30. Here, the cavity 35 of the upper die 30 is formed so that the concave portion 22g recessed radially inward is formed in the connection portion 22, which means that the portion of the lower face 30a of the upper die 30 corresponding to the concave portion 22g is formed in a convex shape facing radially inward. This makes it possible to press a relatively wide region of the end face 11 of the rotor core 10 radially outward from the concave portion 22g by the lower face 30a of the upper die 30 (see FIG. 5). As a result, it is possible to suppress (horizontally) deformation of the portion of the rotor core 10 radially outward from the concave portion 22g due to the pressing force (friction force) of the upper die 30.

[0068] Furthermore, the resin filled in the hollow portion 35 of the upper die 30, the magnet accommodating hole 2, and the hollow portion 41 of the lower die 40 is cured, thereby forming the connecting portion 22, the filling portion 21, and the connecting portion 23.

[0069] Then, in step S5, a process is performed in which the upper die 30, the lower die 40, and the pin members 50 are retracted. By retracting the upper die 30 from the rotor core 10, gate marks 22a (see FIG. 1) are formed at circumferential positions corresponding to the centers of the magnet accommodating holes 2 that are adjacent to each other in the circumferential direction. In addition, by retracting the pin members 50 from the rotor core 10, holes 23a corresponding to the pin members 50 are formed in the connection portions 23.

[0070] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0071] In this embodiment, as described above, the resin portion 20 is provided at a position that does not overlap the magnet accommodating hole 2 in the axial direction, and includes the gate mark portion 22a corresponding to the resin injection port 31 at the time of molding the resin portion 20. That is, the resin is injected with the injection port 31 disposed at a position that does not overlap the magnet accommodating hole 2 in the axial direction. This makes it possible to prevent the resin injected from the injection port 31 from being injected directly (in a straight path) into the magnet accommodating hole 2, compared to the case where the resin is injected with the resin injection port 31 disposed at a position that overlaps the magnet accommodating hole 2 in the axial direction. As a result, the pressure of the resin applied to the magnet accommodating hole 2 can be reduced. This makes it possible to prevent the rotor core 10 from being deformed due to the increase in the pressure of the resin applied to the magnet accommodating hole 2 at the time of resin injection.

[0072] Furthermore, in this embodiment, as described above, gate mark portion 22a is provided at one axial end portion 22b of connection portion 22 at a circumferential position corresponding to a position between circumferentially adjacent magnet accommodating holes 2. This causes the resin injected from injection port 31 to be dispersed among circumferentially adjacent magnet accommodating holes 2, making it possible to more reliably suppress deformation of rotor core 10 caused by an increase in the pressure of resin applied to magnet accommodating holes 2 during resin injection.

[0073] In this embodiment, as described above, the connection portion 22 is provided so as to cover the portion other than the magnet hole outer end 2a, without covering a portion of the magnet hole outer end 2a, which is the radially outer end of each of the magnet accommodating holes 2 adjacent to each other in the circumferential direction, as viewed from one side in the axial direction. Here, the portion (end 2b) of the magnet accommodating hole 2 that is not covered by the connection portion 22 is blocked from one side in the axial direction by the upper mold 30 that injects the resin during resin molding. As a result, during resin molding, the portion of the upper mold 30 that is provided so as to block the portion (end 2b) can prevent the resin in the upper mold 30 from being directly injected into the portion (end 2b) of the magnet accommodating hole 2. As a result, the portion (end 2b) of the magnet accommodating hole 2 can be prevented from being deformed by the pressure of the resin. In addition, when the magnet accommodating hole 2 is disposed radially outward of the rotor core 10, the portion (radially outer portion 13) radially outward of the magnet hole outer end 2a has a relatively small radial thickness and therefore a relatively small mechanical strength. Therefore, since the connection portion 22 does not cover a portion (end 2b) of the magnet hole outer end portion 2a of the magnet accommodating hole 2, the pressure of the resin applied to the portion of the rotor core 10 having relatively low mechanical strength (radially outer portion 13) can be reduced.

[0074] In the present embodiment, as described above, the axial thickness t1 of the portion 21a of the filling portion 21 provided on one axial side of the end portion 1a on one axial side of the permanent magnet 1 is smaller than the axial thickness t2 of the connecting portion 22. This makes it possible to reduce the volume of the portion 21a of the filling portion 21 compared to the case where the axial thickness t1 of the portion 21a of the filling portion 21 is equal to or greater than the axial thickness t2 of the connecting portion 22. As a result, it is possible to reduce the amount of resin injected into the space of the magnet accommodating hole 2 corresponding to the portion 21a of the filling portion 21, and therefore it is possible to reduce the pressure of the resin applied to the portion of the rotor core 10 corresponding to the above-mentioned space of the magnet accommodating hole 2.

[0075] In addition, in this embodiment, as described above, the step of forming the resin portion 20 includes a step of forming the resin portion 20 by injecting the resin with the injection port 31 of the upper die 30 positioned at a position that does not overlap the magnet accommodating hole 2 in the axial direction. This makes it possible to prevent the resin injected from the upper die 30 from being injected directly (through a linear path) into the magnet accommodating hole 2, compared to the case where the resin is injected with the injection port 31 positioned at a position that overlaps the magnet accommodating hole 2 in the axial direction. As a result, the pressure of the resin applied to the magnet accommodating hole 2 can be reduced. This makes it possible to provide a manufacturing method for the rotor 100 that can prevent the rotor core 10 from being deformed due to the increase in the pressure of the resin applied to the magnet accommodating hole 2 when the resin is injected.

[0076] Furthermore, the resin is injected with the permanent magnet 1 supported by the pin member 50 from the other axial side. This allows the position of the permanent magnet 1 to be easily adjusted by adjusting the position of the pin member 50, so that the space in the magnet accommodating hole 2 on one axial side of the permanent magnet 1 can be easily reduced. As a result, the volume of the resin injected into the space can be easily reduced, so that the pressure of the resin applied to the portion of the rotor core 10 corresponding to the one axial side of the permanent magnet 1 can be reduced. As a result, deformation of the rotor core 10 can be more easily suppressed.

[0077] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than the description of the above embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0078] For example, in the above embodiment, an example has been shown in which the gate mark portion 22a is provided at a circumferential position corresponding to the position between the magnet accommodating holes 2 adjacent to each other in the circumferential direction, but the present invention is not limited to this. For example, the gate mark portion 22a may be provided at a position shifted to one radial side with respect to each of the multiple magnet accommodating holes 2. In this case, the connection portion 22 does not need to be provided on the end face 11 of the rotor core 10.

[0079] In the above embodiment, the gate mark portion 22a is provided at a circumferential position corresponding to the center of the magnet accommodating holes 2 adjacent to each other in the circumferential direction, but the present invention is not limited to this. For example, the gate mark portion 22a may be provided at a position between the magnet accommodating holes 2 adjacent to each other in the circumferential direction and closer to one of the magnet accommodating holes 2.

[0080] In the above embodiment, the connecting portion 22 does not cover a portion of the magnet hole outer end 2a of the magnet accommodating hole 2, but the present invention is not limited to this. For example, the connecting portion 22 may be provided so as not to cover the entire magnet hole outer end 2a of the magnet accommodating hole 2. Also, the connecting portion 22 may cover the entire magnet hole outer end 2a of the magnet accommodating hole 2.

[0081] In the above embodiment, an example has been shown in which the axial thickness t1 of portion 21a of filling portion 21 is smaller than the axial thickness t2 of connection portion 22, but the present invention is not limited to this. For example, thickness t1 may be greater than or equal to thickness t2. Furthermore, thickness t1 may be smaller than thickness t2 and greater than thickness t4 of electromagnetic steel sheet 10a (thickness t5 of electromagnetic steel sheet 10b).

[0082] In the above embodiment, the gate mark portion 22a is provided radially inward with respect to the region S between the magnet accommodating holes 2 adjacent to each other in the circumferential direction, but the present invention is not limited to this. The gate mark portion 22a may be provided radially outward with respect to the region S.

[0083] In the above embodiment, the resin is injected from above while the permanent magnet 1 is supported from below by the pin members 50, but the present invention is not limited to this. The resin may be injected from below while the pin members 50 are disposed above the permanent magnet 1 to restrict the upward movement of the permanent magnet 1.

[0084] In the above embodiment, the eight magnet accommodating holes 2 are arranged circumferentially at intervals from one another, but the present invention is not limited to this. For example, magnetic poles including two magnet accommodating holes arranged in a V-shape may be arranged circumferentially at intervals from one another. In this case, it is preferable that the gate mark is arranged at a circumferential position (center) corresponding to the position between the two magnet accommodating holes arranged in a V-shape. [Explanation of symbols]

[0085] 1. Permanent magnet 1a End (one end of the permanent magnet) 2 Magnet housing hole 2a Outer end of magnet hole 10 Rotor core 11 End face (first end face) 20 Resin part 21 Filling section Part 21a (part on one side of the permanent magnet in the filling part) 22 Connection 22b End (end of connection part) 22a Gate trace 31 Inlet 50 Pin material 100 rotors t1 Thickness (thickness of the part on one side of the filling part beyond the permanent magnet) t2 Thickness (thickness of connection part)

Claims

1. a rotor core including a plurality of magnet accommodating holes extending along an axial direction and circumferentially spaced from one another; A permanent magnet accommodated in each of the plurality of magnet accommodating holes; a resin portion including a filled portion formed by filling each of the plurality of magnet accommodating holes with a resin, the resin portion includes a gate mark portion corresponding to a resin injection port at a time of molding the resin portion, the gate mark portion being provided at a position not overlapping with the magnet accommodating hole in the axial direction, A rotor, wherein the gate mark portion is provided radially inward of a region sandwiched between the magnet accommodating holes adjacent to each other in the circumferential direction of the rotor core.

2. the resin portion includes a connection portion formed of resin that connects the filled portions filled in the magnet accommodating holes adjacent to each other in the circumferential direction of the rotor core to each other at a first end face on one side in the axial direction of the rotor core, The rotor according to claim 1 , wherein the gate mark portion is provided at an end portion on one side in the axial direction of the connection portion, at a circumferential position corresponding to a position between the magnet accommodating holes adjacent to each other in the circumferential direction.

3. The rotor described in claim 2, wherein the connection portion is arranged to cover portions other than the magnet hole outer ends, without covering at least a portion of the magnet hole outer ends, which are the radially outer ends, of each of the magnet accommodating holes adjacent to each other in the circumferential direction, when viewed from one side in the axial direction.

4. A rotor as described in claim 2 or 3, wherein the axial thickness of the filling portion in the magnet accommodating hole, which is located on one side of the axial end of the permanent magnet, is smaller than the axial thickness of the connection portion located axially outside the magnet accommodating hole.

5. A manufacturing method of a rotor including a rotor core including a plurality of magnet accommodating holes provided to extend along an axial direction and circumferentially spaced apart from one another, and a permanent magnet accommodated in each of the plurality of magnet accommodating holes, comprising: placing an upper mold including a resin injection port on one side of the rotor core in the axial direction; a step of supporting the permanent magnets by the pin members by contacting the permanent magnets accommodated in each of the plurality of magnet accommodating holes from the other side in the axial direction; and forming a resin portion including a filling portion filled in each of the plurality of magnet accommodating holes by injecting resin from one side in the axial direction using the upper mold while the permanent magnet is supported from the other side in the axial direction by the pin member, the step of forming the resin portion includes a step of forming the resin portion by injecting resin in a state in which the injection port of the upper mold is disposed at a position not overlapping with the magnet accommodating hole in the axial direction, A method for manufacturing a rotor, wherein the process of forming the resin portion includes a process of injecting the resin from the injection port located radially inward of the area sandwiched between adjacent magnet accommodating holes in the circumferential direction of the rotor core.

Images