Rotor

Abstract

To provide a rotor in which a permanent magnet can be fixed to a side closer to a stator in a magnet housing hole.SOLUTION: A rotor 100 includes a permanent magnet M, and a rotor core 101 that includes a magnet housing hole 2 having a magnet insertion portion 20 in which the permanent magnet M is inserted and a magnet fixing resin filled portion which is filled with a resin for fixing the permanent magnet M, and that is formed by layering a plurality of electromagnetic steel sheets. The rotor core 101 further includes a magnet non-housing hole 3 disposed on a radially inner side of the magnet housing hole 2, and a communication hole portion 4 that is disposed on a radially inner side of the permanent magnet M and that provides communication between the magnet housing hole 2 and the magnet non-housing hole 3.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a rotor, and more particularly to a rotor including a rotor core formed by laminating a plurality of electromagnetic steel sheets. [Background technology]

[0002] 2. Description of the Related Art Conventionally, rotors have been known that include a rotor core formed by laminating a plurality of electromagnetic steel sheets (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses a rotor having a rotor core formed by laminating a plurality of electromagnetic steel sheets. The rotor core is provided with a magnet accommodating hole including a magnet insertion portion into which a permanent magnet is inserted and a resin-filled portion into which a resin for fixing the permanent magnet is filled. The permanent magnet is fixed by being introduced into the magnet insertion portion from the axial end of the magnet accommodating hole and being filled with resin. The magnet accommodating hole has a shape that follows the outer shape of the permanent magnet when viewed from the axial direction so that the rough position of the inserted permanent magnet is determined. In addition, a clearance is provided between the magnet accommodating hole and the permanent magnet in consideration of the insertability of the permanent magnet. This clearance becomes the resin-filled portion into which the resin is filled. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-112422 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the rotor described in the above Patent Document 1, it is necessary to fix the permanent magnet by introducing resin from the axial end of the magnet accommodating hole into the resin-filled portion, which is the clearance between the magnet accommodating hole and the permanent magnet, and filling it. Therefore, the permanent magnet is not positioned inside the magnet accommodating hole, and resin is introduced from the axial direction into the portion around the permanent magnet in the magnet accommodating hole, so that the position of the permanent magnet placed inside the magnet accommodating hole after filling with resin is not fixed. In other words, there is a problem that the permanent magnet may be fixed on the side farther from the stator inside the magnet accommodating hole. Note that the farther the permanent magnet of the rotor is positioned from the stator, the more difficult it is for the magnetic flux of the permanent magnet to reach the stator side, and the efficiency of the motor decreases.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a rotor in which a permanent magnet can be fixed inside a magnet accommodating hole on the side closer to the stator. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a rotor in one aspect of the present invention comprises a permanent magnet, and a rotor core formed by stacking a plurality of electromagnetic steel plates, the rotor core including a magnet accommodating hole having a magnet insertion portion into which the permanent magnet is inserted and a magnet fixing resin filling portion into which is filled with resin that fixes the permanent magnet, the rotor core further including a non-magnet accommodating hole arranged radially inward of the magnet accommodating hole, and a communicating hole portion arranged radially inward of the permanent magnet and communicating between the magnet accommodating hole and the non-magnet accommodating hole.

[0008] In the rotor according to one aspect of the present invention, as described above, the rotor core is provided with a magnet accommodating hole having a magnet fixing resin filling portion, a magnet non-accommodating hole arranged radially inside the magnet accommodating hole, and a communication hole arranged radially inside the permanent magnet and communicating between the magnet accommodating hole and the magnet non-accommodating hole. This allows resin to flow from the radial inside of the permanent magnet toward the permanent magnet through the communication hole arranged radially inside the permanent magnet and communicating between the magnet accommodating hole and the magnet non-accommodating hole. Therefore, the force of the resin flowing radially outward toward the permanent magnet inside the communication hole portion pushes the permanent magnet radially outward, and the resin can be filled in the magnet fixing resin filling portion with the permanent magnet positioned radially outward. As a result, the permanent magnet can be fixed inside the magnet accommodating hole on the side closer to the stator. Also, instead of filling the inside of the magnet accommodating hole with resin only from the axial end of the magnet accommodating hole as in the conventional method, the resin can be filled inside the magnet accommodating hole from the communication hole on the radial inside. As a result, the resin can be spread throughout the magnet accommodating hole even with a relatively small resin injection pressure.

[0009] In the rotor according to the above aspect, the communicating hole portions, the magnet accommodating holes and the magnet non-accommodating holes are preferably formed in a constricted shape in the circumferential direction such that the communicating hole portions are narrower than the magnet accommodating holes and the magnet non-accommodating holes.

[0010] With this configuration, the communicating hole portion can be made relatively small, so that when a permanent magnet is inserted into the magnet accommodating hole, a portion of the permanent magnet is positioned in the communicating hole portion, preventing the permanent magnet from tilting.

[0011] In the rotor according to the above aspect, preferably, the magnet fixing resin filling portion has a pair of circumferential end side resin portions provided on both circumferential sides of the permanent magnet, and the communicating hole portion extends radially along a circumferential center line extending radially of the permanent magnet, and is positioned circumferentially midway between the pair of circumferential end side resin portions.

[0012] With this configuration, the permanent magnets, the circumferential end side resin portions, and the communicating hole portions can be evenly positioned relative to the center line in the circumferential direction, so that resin can be evenly supplied to the permanent magnets and the circumferential end side resin portions via the communicating hole portions.

[0013] In this case, preferably, the magnet fixing resin filling portion is arranged to extend circumferentially along the radially inner inner surface of the permanent magnet, and has a radially inner resin portion connecting the communicating hole portion and the circumferential end side resin portion, and the permanent magnet is positioned radially outward inside the magnet accommodating hole by the radially inner resin portion.

[0014] With this configuration, the permanent magnet can be reliably fixed inside the magnet accommodating hole on the side closer to the stator, thereby more effectively improving the efficiency of the motor.

[0015] In the rotor according to the above aspect, the following configuration is also possible.

[0016] (Additional note 1) That is, in the above rotor, the circumferential width of the connection points of the communicating holes with the magnet accommodating holes is 1.4 mm or less, and the circumferential width of the connection points of the communicating holes with the non-magnet accommodating holes is 3.8 mm or less.

[0017] With this configuration, the circumferential width of the connection point of the communicating hole portion with the magnet accommodating hole is set to 1.4 mm or less, and the circumferential width of the connection point of the communicating hole portion with the non-magnet accommodating hole is set to 3.8 mm or less, so that resin can be more effectively supplied from the communicating hole portion to the magnet accommodating hole and the permanent magnet inside the magnet accommodating hole can be more effectively pushed radially outward by the resin.

[0018] (Additional note 2) In the rotor described above, the communication hole portion is provided from one end face to the other end face in the axial direction of the rotor core.

[0019] With this configuration, since the communicating holes can be provided all along the axial direction, the resin can be evenly supplied from the communicating holes to the magnet accommodating holes all along the axial direction.

[0020] (Additional note 3) In the rotor, the communication hole portion is partially provided only on one side in the axial direction.

[0021] With this configuration, the communication hole portion is partially provided only on one side in the axial direction, so that the total amount of resin filled in the rotor core can be reduced.

[0022] (Additional note 4) In the rotor, when viewed from the axial direction, a circular arc-shaped R-chamfered portion is provided at a connection portion of the communication hole portion with the non-magnet containing hole.

[0023] With this configuration, the communicating hole portion and the non-magnet-containing hole can be smoothly connected by the R-chamfered portion, so that the resin can be smoothly introduced from the non-magnet-containing hole to the communicating hole portion. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a perspective view showing a rotor according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] 2 is a diagram showing a rotor core of the rotor according to the embodiment from one axial side. FIG. [Figure 4] FIG. 5 is a partial enlarged view of a portion K in FIG. [Diagram 5] 5A to 5C are diagrams for explaining a resin filling step of filling resin into a rotor core using an upper mold and a lower mold of the embodiment. [Figure 6] 5 is a partial enlarged view showing a communication hole portion according to a modified example, and corresponds to FIG. 4. FIG. [Figure 7] FIG. 3 is a cross-sectional view showing a rotor core according to a modified example, and corresponds to FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0026] (Embodiment) The configuration of a rotor 100 provided in a motor will be described with reference to FIGS.

[0027] As shown in FIGS. 1 to 3, the motor is configured as an interior permanent magnet motor (IPM motor) in which permanent magnets M are embedded in a rotor 100 radially inside a stator S (see FIG. 3).

[0028] In each figure, the axial direction of rotor core 101 is indicated by the Z direction. One of the Z directions is indicated by the Z1 direction, and the other is indicated by the Z2 direction. The Z direction is the direction in which the rotational center axis Cr, which is the center of rotation of rotor 100, extends. The Z1 direction side of rotor core 101 is the side where resin is filled to fix permanent magnets M. In other words, the Z1 direction side is the side where a nozzle (not shown) that injects resin into the interior of rotor core 101 is located.

[0029] In each drawing, the radial direction of the rotor core 101 is indicated by the R direction. Of the R directions, the direction facing radially outward is indicated by the R1 direction, and the direction facing radially inward is indicated by the R2 direction. The R direction is perpendicular to the axial direction. The R direction is also the direction in which the center line L1 of the permanent magnet M extends.

[0030] The circumferential center line L1 of the permanent magnet M is also the circumferential center line of the magnet accommodating hole 2, the magnet non-accommodating hole 3, and the communicating hole portion 4, which will be described later. In other words, the circumferential center lines of the permanent magnet M, the magnet accommodating hole 2, the magnet non-accommodating hole 3, and the communicating hole portion 4 coincide with one another.

[0031] In each drawing, the circumferential direction of rotor core 101 is indicated by direction C. Direction C is perpendicular to the axial direction.

[0032] As shown in FIG. 2, the rotor 100 includes a permanent magnet M, a rotor core 101, and a resin connecting portion .

[0033] Rotor core 101 is formed by stacking multiple electromagnetic steel sheets in the axial direction, with the thickness direction being in the axial direction of rotor core 101. Each electromagnetic steel sheet is generally formed in an annular shape having a through hole in the center through which the rotor shaft passes.

[0034] The rotor core 101 includes a weight reduction hole 1, a magnet accommodating hole 2, a magnet non-accommodating hole 3, and a communication hole portion 4.

[0035] (Configuration of weight-reducing holes) The weight-saving hole 1 is a hole formed to reduce the thickness of the rotor core 101 to reduce its weight, and penetrates the rotor core 101 in the axial direction. The weight-saving hole 1 extends in the axial direction while maintaining the same cross-sectional shape. The weight-saving hole 1 has a substantially rectangular shape when viewed in the axial direction (when viewed in the direction along the axial direction). The weight-saving hole 1 is provided separately from the magnet accommodating hole 2, the magnet non-accommodating hole 3, and the communicating hole portion 4.

[0036] A plurality of weight-saving holes 1 are provided in a line in the circumferential direction. As an example, ten weight-saving holes 1 are provided. The magnet accommodating holes 2 are arranged at a predetermined angular interval θ in the circumferential direction. The magnet accommodating holes 2 are evenly provided in the circumferential direction so as not to upset the balance when the rotor 100 rotates. The number of magnet accommodating holes is not limited to the above ten.

[0037] (Configuration of magnet housing hole) As shown in Figures 3 and 4, the magnet accommodating hole 2 is disposed radially outward (R1 direction side) of the weight reduction hole 1. The magnet accommodating hole 2 is a hole formed for accommodating a permanent magnet M therein, and penetrates the rotor core 101 in the axial direction. The magnet accommodating hole 2 extends in the axial direction while maintaining the same cross-sectional shape. One magnet accommodating hole 2 is provided for each permanent magnet M. The magnet accommodating hole 2 and the permanent magnet M have approximately the same size in the axial direction. At least the rotor core 101 is configured so that the permanent magnet M accommodated in the magnet accommodating hole 2 does not protrude from the magnet accommodating hole 2 in the axial direction.

[0038] The magnet accommodating hole 2 has a substantially rectangular shape when viewed from the axial direction. In detail, the magnet accommodating hole 2 is generally formed in a rectangular shape with a long side in a direction perpendicular to the radial direction and a short side in the radial direction when viewed from the axial direction.

[0039] A plurality of magnet accommodating holes 2 are provided so as to be aligned in the circumferential direction. As an example, ten magnet accommodating holes 2 are provided. The plurality of magnet accommodating holes 2 are also arranged at a predetermined angular interval θ in the circumferential direction. The number of magnet accommodating holes is not limited to the above ten.

[0040] The magnet accommodating hole 2 has an outer surface 2a extending in the circumferential direction (direction perpendicular to the radial direction) when viewed from the axial direction, and an inner surface 2b disposed radially inside the outer surface 2a. The outer surface 2a and the inner surface 2b are part of the inner surface that forms the magnet accommodating hole 2.

[0041] The outer surface 2a of the magnet accommodating hole 2 and the outer surface M1 of the permanent magnet M are disposed opposite to each other in the radial direction. As an example, the outer surface 2a is formed as a flat surface substantially parallel to the outer surface M1. Note that the outer surface of the magnet accommodating hole and the outer surface of the permanent magnet may be formed in other shapes, such as an arc shape centered on the rotation center of the rotor.

[0042] The outer surface 2a of the magnet accommodating hole 2 and the outer surface M1 of the permanent magnet M are in contact with each other. In this case, the contact between the outer surface 2a and the outer surface M1 is surface contact. Note that the outer surface of the magnet accommodating hole and the outer surface of the permanent magnet may be disposed opposite each other with an extremely thin resin interposed between them, without being in contact with each other.

[0043] As an example, the inner surface 2b of the magnet accommodating hole 2 is a surface that is approximately parallel to the outer surface 2a. The inner surface 2b is connected to the communication hole portion 4 from the radial inside. Therefore, a pair of inner surfaces 2b are provided, one on each side of the magnet accommodating hole 2 in the circumferential direction.

[0044] In the radial direction, the permanent magnet M is disposed closer to an inner side surface 2b of the magnet accommodating hole 2 than to an outer side surface 2a of the magnet accommodating hole 2. The permanent magnet M is disposed biased radially outward (toward the R1 direction) inside the magnet accommodating hole 2 by a radially inner resin portion 21b described later. In other words, the permanent magnet M is disposed biased toward the stator S side inside the magnet accommodating hole 2 by a radially inner resin portion 21b described later.

[0045] The magnet accommodating holes 2 are provided close to the annular outer peripheral surface 101d of the rotor core 101 in order to be close to the stator S (see FIG. 3) in the radial direction. For this reason, the outermost peripheral portion 101c (bridge portion) between the outer peripheral surface 101d of the rotor core 101 and the magnet accommodating holes 2 is formed to be relatively thin.

[0046] Here, since the outermost portion 101c is relatively thin, in the manufacturing method of the rotor 100, it is necessary to adjust (suppress) the resin injection pressure within a preferred range of pressure so that the outermost portion 101c does not deform when filling the rotor core 101 with resin, or so that the deformation of the outermost portion 101c is kept small.

[0047] Further, the magnet accommodating hole 2 has a magnet insertion portion 20 and a magnet fixing resin filled portion 21.

[0048] (Configuration of magnet insertion portion of magnet accommodating hole) 4, the magnet insertion portion 20 is a portion of the magnet accommodating hole 2 into which the permanent magnet M is inserted. In other words, the magnet insertion portion 20 is an area within the magnet accommodating hole 2 where the permanent magnet M is placed and fixed in a predetermined position by filling with resin. The magnet insertion portion 20 is the center portion of the magnet accommodating hole 2 in the circumferential direction.

[0049] (Configuration of magnet fixing resin filled part of magnet accommodating hole) The magnet fixing resin filled portion 21 is a portion inside the magnet accommodating hole 2 that is filled with resin to fix the permanent magnet M. In short, the magnet fixing resin filled portion 21 is a clearance portion between the inner peripheral surface of the magnet accommodating hole 2 and the permanent magnet M inserted into the magnet accommodating hole 2. Due to the magnet fixing resin filled portion 21 which is this clearance, the rotor core 101 is configured so that the permanent magnet M can be easily inserted into the magnet accommodating hole 2 and the inserted permanent magnet M can be fixed with resin. The magnet fixing resin filled portion 21 is a relatively small (narrow) space.

[0050] The magnet fixing resin filling portion 21 has a circumferential end side resin portion 21a and a radially inner resin portion 21b.

[0051] (Configuration of the “circumferential end side resin portion” of the magnet fixing resin filling portion of the magnet accommodating hole) A pair of circumferential end-side resin portions 21a are provided on both circumferential sides of the permanent magnet M. The circumferential end-side resin portions 21a are configured to be line-symmetrical with respect to the center line L1. Therefore, the pair of circumferential end-side resin portions 21a sandwich the magnet insertion portion 20 (permanent magnet M) from both circumferential sides.

[0052] When viewed from the axial direction, the area of ​​one circumferential end side resin portion 21a located on either side in the circumferential direction of magnet insertion portion 20 is smaller than the area of ​​magnet insertion portion 20. Also, when viewed from the axial direction, the area of ​​one circumferential end side resin portion 21a located on either side in the circumferential direction of magnet insertion portion 20 is smaller than the area of ​​non-magnet containing hole 3.

[0053] (Configuration of the "radially inner resin portion" of the magnet fixing resin filling portion of the magnet accommodating hole) The radially inner resin portion 21b is provided to extend in the circumferential direction along an inner surface M2 on the radially inner side of the permanent magnet M. The radially inner resin portion 21b connects the communication hole portion 4 and the circumferential end side resin portion 21a inside the magnet accommodating hole 2.

[0054] The inner surface 2b of the magnet accommodating hole 2 and the inner surface M2 of the permanent magnet M are arranged in contact with each other in the radial direction or facing each other with a relatively small gap therebetween. The distance D2 between the inner surface 2b of the magnet accommodating hole 2 and the inner surface M2 of the permanent magnet M is much larger than the distance D1 between the outer surface 2a of the magnet accommodating hole 2 and the outer surface M1 of the permanent magnet M. The distance D1 is zero or approximately zero. Therefore, in the radial direction, the thickness (distance D2) of the radially inner resin portion 21b is relatively small and thin, but is much larger than the distance D1 compared to the distance D1. The distance D1 between the outer surface 2a of the magnet accommodating hole 2 and the outer surface M1 of the permanent magnet M is approximately uniform at any position in the circumferential direction. That is, the permanent magnet M is arranged inside the magnet accommodating hole 2 without being tilted with respect to the magnet accommodating hole 2 when viewed from the axial direction.

[0055] (Configuration of non-magnet hole) The non-magnet holes 3 are holes for filling with resin without accommodating a permanent magnet M. The non-magnet holes 3 penetrate the rotor core 101 in the axial direction. The non-magnet holes 3 extend in the axial direction while maintaining the same cross-sectional shape. The non-magnet holes 3 are disposed radially inside (R2 direction side) the magnet accommodating holes 2 and radially outside (R1 direction side) the weight-saving holes 1. The non-magnet holes 3 are sandwiched between the magnet accommodating holes 2 and the weight-saving holes 1 in the radial direction.

[0056] A plurality of magnet non-housing holes 3 are provided, lined up in the circumferential direction. As an example, ten magnet non-housing holes 3 are provided, the same number as the magnet accommodating holes 2. The plurality of magnet non-housing holes 3 are also arranged at a predetermined angular interval θ in the circumferential direction. The number of magnet non-housing holes 3 is not limited to the above ten, and does not have to be the same number as the magnet accommodating holes. When viewed from the axial direction, the area of ​​the magnet non-housing holes 3 is larger than the area of ​​the magnet fixing resin filling portion 21. The circumferential width of the magnet non-housing holes 3 is smaller than the circumferential width of the magnet accommodating holes 2.

[0057] The magnet non-containing hole 3 has a shape in which the center portion protrudes radially outward (toward the R1 direction) when viewed from the axial direction. That is, the magnet non-containing hole 3 is formed so that the circumferential width gradually decreases toward the radially outward side when viewed from the axial direction. Specifically, the magnet non-containing hole 3 is generally formed in an isosceles triangle shape with the center portion protruding radially outward (toward the R1 direction) when viewed from the axial direction.

[0058] In this way, by forming the non-magnet accommodating hole 3 in a triangular shape, it is configured not to impede the flow of magnetic flux Ma emerging from the radial inside of the permanent magnet M accommodated in the magnet accommodating hole 2 toward adjacent permanent magnets M. In other words, the non-magnet accommodating hole 3 is formed in a shape that is closest to the permanent magnet M accommodated in the magnet accommodating hole 2 at the middle position in the circumferential direction. Also, the non-magnet accommodating hole 3 is formed in a shape that is farthest from the permanent magnet M accommodated in the magnet accommodating hole 2 at both end positions in the circumferential direction.

[0059] (Configuration of communication hole portion) The communicating hole portion 4 communicates between the magnet accommodating holes 2 and the non-magnet accommodating holes 3. The communicating hole portion 4 is a flow path for resin that allows the resin that has flowed into the non-magnet accommodating holes 3 to flow into the magnet accommodating holes 2 when filling the rotor core 101 with resin. The communicating hole portion 4 penetrates the rotor core 101 in the axial direction. That is, the communicating hole portion 4 is provided from one end face 101a (see FIG. 1) to the other end face 101b (see FIG. 1) in the axial direction of the rotor core 101. The communicating hole portion 4 extends in the axial direction while maintaining the same cross-sectional shape.

[0060] The communication hole portion 4 is disposed radially inside (R2 direction side) of the magnet accommodating hole 2 and radially outside (R1 direction side) of the magnet non-accommodating hole 3. The communication hole portion 4 is sandwiched in the radial direction between the magnet accommodating hole 2 and the magnet non-accommodating hole 3. One communication hole portion 4 is provided for each set of one magnet accommodating hole 2 and one magnet non-accommodating hole 3 that face each other in the radial direction.

[0061] The communicating hole portion 4 communicates between the apex located on the radially outer side of the triangular non-magnet containing hole 3 and the inner surface M2 of the permanent magnet M. When viewed from the axial direction, the communicating hole portion 4 is formed by a pair of linear portions 4a (flat surfaces) opposing each other in the circumferential direction. The communicating hole portion may also be formed by a pair of curved portions opposing each other in the circumferential direction.

[0062] The communicating hole portion 4, the magnet accommodating hole 2, and the magnet non-accommodating hole 3 are formed in a constricted shape in the circumferential direction such that the communicating hole portion 4 is narrower than the magnet accommodating hole 2 and the magnet non-accommodating hole 3. That is, the circumferential width of the communicating hole portion 4 (maximum circumferential width W10) is smaller than the circumferential width of the magnet non-accommodating hole 3 (maximum circumferential width W11) and the circumferential width of the magnet accommodating hole 2 (maximum circumferential width W12). Furthermore, the circumferential width of the communicating hole portion 4 is smaller than the circumferential width of the permanent magnet M. In short, the entire communicating hole portion 4 is arranged to be contained between both circumferential end faces of the permanent magnet M.

[0063] The communication hole portion 4 extends radially along a circumferential center line L1 that extends in the radial direction of the permanent magnet M, and is disposed at a midpoint in the circumferential direction between the pair of circumferential end side resin portions 21a.

[0064] A connection point 41 of the communication hole portion 4 with the magnet accommodating hole 2 is disposed circumferentially inward of both ends of the permanent magnet M. In other words, the connection point 41 of the communication hole portion 4 with the magnet accommodating hole 2 is disposed in a position facing the permanent magnet M in the radial direction. Therefore, when the resin that has flowed into the magnet non-accommodating hole 3 flows through the communication hole portion 4 toward the magnet accommodating hole 2, a flow of resin is generated within the communication hole portion 4 from the radial inside of the permanent magnet M toward the outer surface M1 of the permanent magnet M.

[0065] When the resin that has flowed into the magnet non-accommodating hole 3 flows through the communicating hole portion 4 toward the magnet accommodating hole 2, a force that faces radially outward acts on the permanent magnet M due to the resin flowing through the communicating hole portion 4 toward the permanent magnet M. In other words, the permanent magnet M is pressed radially outward by the resin. As a result, the permanent magnet M is positioned inside the magnet accommodating hole 2, biased toward the radially outward side.

[0066] The circumferential width W1 of the connection portion 41 of the communicating hole portion 4 with the magnet accommodating hole 2 is set in the range of 1.4 mm or less. The circumferential width W2 of the connection portion 41 of the communicating hole portion 4 with the magnet non-accommodating hole 3 is set in the range of 3.8 mm or less. In this embodiment, the circumferential width W1 of the connection portion 41 of the communicating hole portion 4 with the magnet accommodating hole 2 is larger than the circumferential width W2 of the connection portion 40 of the communicating hole portion 4 with the magnet non-accommodating hole 3. In this embodiment, the above W10 is equal to W1. In addition, the communicating hole portion 4 is formed in a flared shape in which the radially outer width is larger than the radially inner width.

[0067] When viewed from the axial direction, a connection portion 40 of the communicating hole portion 4 with the non-magnet containing hole 3 is provided with an arc-shaped R chamfered portion 42. The connection portion 40 of the communicating hole portion 4 with the non-magnet containing hole 3 is formed in a rounded shape without corners so as not to impede the flow of resin flowing from the non-magnet containing hole 3 into the communicating hole portion 4. In short, the communicating hole portion 4 and the non-magnet containing hole 3 are smoothly connected by the arc surface of the R chamfered portion 42.

[0068] (Structure of resin connecting part) 1 and 2, a pair of resin connecting portions 102 are provided on one end face 101a and the other end face 101b in the axial direction of rotor core 101. Resin connecting portion 102 extends in a direction perpendicular to the axial direction along one end face 101a and the other end face 101b. Resin connecting portion 102 is formed in an annular shape centered on rotational central axis Cr of rotor 100.

[0069] When viewed from the axial direction, the resin connecting portion 102 covers the magnet accommodating holes 2, the magnet non-accommodating holes 3, and the communicating hole portions 4 from the axial outside of the rotor core 101. In other words, the resin connecting portion 102 is configured to connect the axial end portion of the resin filled in the magnet fixing resin filled portion 21 of the magnet accommodating hole 2, the axial end portion of the resin filled in the magnet non-accommodating holes 3, and the axial end portion of the resin filled in the communicating hole portions 4.

[0070] (Rotor manufacturing method) 3 to 5, the steps of the method for manufacturing rotor 100 will be described in order. Here, the steps up to fixing permanent magnets M to rotor core 101 with resin will be described.

[0071] The manufacturing method of the rotor 100 includes a core forming process in which a plurality of electromagnetic steel sheets are stacked in the axial direction to form the rotor core 101. By this core forming process, the rotor core 101 provided with the magnet accommodating holes 2, the magnet non-accommodating holes 3, and the communicating hole portions 4 is formed.

[0072] As a next step, the manufacturing method of the rotor 100 includes an insertion step of inserting the permanent magnet M into the magnet insertion portion 20 of the magnet accommodating hole 2 of the rotor core 101. By this insertion step, the permanent magnet M is accommodated in the magnet accommodating hole 2 of the rotor core 101. Note that, when the insertion step is completed, there is a slight clearance between the outer side surface M1 of the permanent magnet M and the outer side surface 2a of the magnet accommodating hole 2, which face each other, and there is a slight clearance between the inner side surface M2 of the permanent magnet M and the inner side surface 2b of the magnet accommodating hole 2, which face each other. There is also clearance on both sides of the permanent magnet M in the circumferential direction. Therefore, when the insertion step is completed, the position of the rotor core 101 inside the magnet accommodating hole 2 is not determined.

[0073] As the next step, the manufacturing method of the rotor 100 includes a resin filling step in which the rotor core 101 is clamped between an upper mold 50 (see Figure 5) and a lower mold 51 (see Figure 5) having a resin injection passage, and resin is filled into the magnet non-containing holes 3, the communicating hole portions 4, and the magnet fixing resin filled portions 21.

[0074] In the resin filling process, first, resin is injected through a resin injection port of the upper die 50, thereby filling the space between the upper die 50 and one end face 101a of the rotor core 101 (the space for forming the resin connecting portion 102).

[0075] In the resin filling process, the resin that has flowed into the rotor core 101 from one end face 101a of the rotor core 101 flows from the non-magnet accommodating holes 3 into the communicating hole portion 4, and then flows through the communicating hole portion 4 toward the permanent magnet M on the radially outer side, thereby flowing into the magnet accommodating hole 2. The resin that has flowed into the magnet accommodating hole 2 (radially inner resin portion 21b) presses the permanent magnet M radially outward. As a result, the permanent magnet M is positioned inside the magnet accommodating hole 2, biased toward the radially outer side, which is the stator S (see FIG. 3) side. In other words, the permanent magnet M abuts or nearly abuts against the outer surface 2a of the magnet accommodating hole 2.

[0076] Then, in the resin filling step, resin is filled into the circumferential end side resin portion 21a via the radially inner resin portion 21b of the magnet accommodating hole 2. The permanent magnet M is fixed in a state in which it is positioned radially outward inside the magnet accommodating hole 2 by the resin filled into the radially inner resin portion 21b and the circumferential end side resin portion 21a. The resin not only flows into the magnet accommodating hole 2 from the radially inner side via the communication hole portion 4, but also flows into the magnet accommodating hole 2 from both axial ends (resin connecting portions 102) of the rotor core 101. This completes the manufacturing method for the rotor 100.

[0077] In this way, rotor 100 is configured so that resin flows into magnet accommodating hole 2 from both communicating hole portion 4 on the radial inside of magnet accommodating hole 2 and both axial ends of rotor core 101. For this reason, when comparing rotor 100 of this embodiment with a conventional rotor in which magnet accommodating holes and magnet non-accommodating holes are provided independently without communicating hole portions, that is, a rotor in which resin flows into the magnet accommodating holes only from both axial ends of the rotor core (hereinafter referred to as a "conventional rotor"), rotor 100 of this embodiment can improve the ease of flow (running property) of resin into magnet fixed resin filled portion 21, which is a relatively narrow space.

[0078] Therefore, even if the injection pressure when injecting resin into the rotor core 101 is relatively small, the rotor 100 can spread the resin throughout the magnet fixing resin filled portion 21 of the magnet accommodating hole 2. The rotor 100 can also prevent voids from occurring in the resin when the magnet fixing resin filled portion 21 is filled with resin.

[0079] Furthermore, as described above, since the outermost portion 101c of the rotor core 101 is relatively thin, in the manufacturing method of the rotor 100, it is necessary to adjust (suppress) the resin injection pressure within a preferred range of pressure so that the outermost portion 101c is not deformed when filling the rotor core 101 with resin, or so that the deformation of the outermost portion 101c is kept small.

[0080] As described above, the rotor 100 of this embodiment is capable of improving the ease of resin flow (running ability) into the magnet fixing resin filling section 21 by using the communicating hole section 4, and therefore, compared to conventional rotors, it is possible to keep the resin injection pressure low enough that the outermost portion 101c is not deformed (deformation is kept small).

[0081] In conventional rotors, it was necessary to adjust the resin injection pressure to a specified pressure within a relatively narrow range in order to satisfy two conflicting requirements: the requirement to increase the resin injection pressure to take into account the ease of resin flow into the magnet-fixing resin-filled section, and the requirement to decrease the resin injection pressure to take into account deformation of the outermost circumference of the rotor core.

[0082] In the rotor 100 of this embodiment, the above-mentioned "requirement to increase the resin injection pressure in consideration of the ease of resin flow into the magnet fixing resin filling portion 21" can be alleviated by providing the communication hole portion 4. In other words, the rotor 100 of this embodiment can increase the allowable pressure range of the resin injection pressure, thereby improving the robustness of the manufacturing method of the rotor 100.

[0083] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0084] In this embodiment, as described above, the rotor core 101 is provided with the magnet accommodating hole 2 having the magnet fixing resin filling portion 21, the magnet non-accommodating hole 3 arranged radially inside the magnet accommodating hole 2, and the communication hole portion 4 arranged radially inside the permanent magnet M and communicating between the magnet accommodating hole 2 and the magnet non-accommodating hole 3. This allows resin to flow from the radial inside of the permanent magnet M toward the permanent magnet M through the communication hole portion 4 arranged radially inside the permanent magnet M and communicating between the magnet accommodating hole 2 and the magnet non-accommodating hole 3. Therefore, the force in the flow direction of the resin flowing radially outward toward the permanent magnet M inside the communication hole portion 4 pushes the permanent magnet M radially outward, and resin can be filled into the magnet fixing resin filling portion 21 in a state in which the permanent magnet M is positioned radially outward. As a result, the permanent magnet M can be fixed on the side closer to the stator S inside the magnet accommodating hole 2. Also, instead of filling the interior of the magnet accommodating hole 2 with resin only from the axial end of the magnet accommodating hole 2 as in the conventional method, the interior of the magnet accommodating hole 2 can be filled with resin from the radially inner communicating hole portion 4 as well. As a result, the resin can be spread throughout the interior of the magnet accommodating hole 2 even with a relatively small resin injection pressure.

[0085] In this embodiment, as described above, the communicating hole portion 4, the magnet accommodating hole 2, and the magnet non-accommodating hole 3 are formed in a constricted shape in the circumferential direction such that the communicating hole portion 4 is narrower than the magnet accommodating hole 2 and the magnet non-accommodating hole 3. This allows the communicating hole portion 4 to be formed relatively small, so that when the permanent magnet M is inserted into the magnet accommodating hole 2, a part of the permanent magnet M is disposed in the communicating hole portion 4, preventing the permanent magnet M from tilting.

[0086] In this embodiment, as described above, the magnet fixing resin filling portion 21 has a pair of circumferential end side resin portions 21a provided on both circumferential sides of the permanent magnet M, and the communicating hole portion 4 extends radially along the circumferential center line L1 extending in the radial direction of the permanent magnet M and is disposed at a midpoint between the pair of circumferential end side resin portions 21a in the circumferential direction. This allows the permanent magnet M, the circumferential end side resin portion 21a, and the communicating hole portion 4 to be evenly disposed with respect to the center line L1 in the circumferential direction, so that resin can be evenly supplied to the permanent magnet M and the circumferential end side resin portion 21a via the communicating hole portion 4.

[0087] In this embodiment, as described above, the magnet fixing resin filling portion 21 is provided so as to extend in the circumferential direction along the radially inner inner surface of the permanent magnet M, and has the radially inner resin portion 21b that connects the communication hole portion 4 and the circumferential end side resin portion 21a, and the permanent magnet M is disposed biased radially outward inside the magnet accommodating hole 2 by the radially inner resin portion 21b. This makes it possible to reliably fix the permanent magnet M to the side closer to the stator S inside the magnet accommodating hole 2, thereby improving the efficiency of the motor.

[0088] In this embodiment, as described above, the circumferential width W1 of the connection portion 41 of the communicating hole portion 4 with the magnet accommodating hole 2 is 1.4 mm or less, and the circumferential width W2 of the connection portion 40 of the communicating hole portion 4 with the magnet non-accommodating hole 3 is 3.8 mm or less. By setting the circumferential width W1 of the connection portion 41 of the communicating hole portion 4 with the magnet accommodating hole 2 to 1.4 mm or less and setting the circumferential width W2 of the connection portion 40 of the communicating hole portion 4 with the magnet non-accommodating hole 3 to 3.8 mm or less, it is possible to more effectively supply resin from the communicating hole portion 4 to the magnet accommodating hole 2, and to more effectively push the permanent magnet M inside the magnet accommodating hole 2 radially outward by the resin.

[0089] In this embodiment, as described above, the communication holes 4 are provided from one end face 101a to the other end face 101b in the axial direction of the rotor core 101. This allows the communication holes 4 to be provided throughout the entire axial direction, so that resin can be evenly supplied from the communication holes 4 to the magnet accommodating holes 2 throughout the entire axial direction.

[0090] In this embodiment, as described above, when viewed from the axial direction, the connecting portion 40 of the communicating hole portion 4 with the non-magnet hole 3 is provided with an arc-shaped R chamfered portion 42. This allows the communicating hole portion 4 and the non-magnet hole 3 to be smoothly connected by the R chamfered portion 42, so that the resin can be smoothly introduced from the non-magnet hole 3 to the communicating hole portion 4.

[0091] [Variations] The above-described embodiments disclosed herein should be considered as illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the above-described embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0092] For example, in the above embodiment, the communication hole portion is formed in a flared shape in which the width on the radially outer side is larger than the width on the radially inner side, but the present invention is not limited to this. In the present invention, the width of the communication hole portion 204 may be constant, as in the modified example of the rotor 200 shown in Fig. 6. In addition, although not shown, the communication hole portion may be formed so that the width on the radially outer side is smaller than the width on the radially inner side.

[0093] In the above embodiment, the communication hole portion is formed as a through hole penetrating the rotor core, but the present invention is not limited to this. In the present invention, the communication hole portion 304 may be partially provided only on one side in the axial direction (Z1 direction side) as in the modified example of the rotor 300 shown in FIG. 7. In this case, an electromagnetic steel plate forming the rotor core 101 is disposed on the other axial side of the communication hole portion 304. As a result, the communication hole portion 304 is partially provided only on one side in the axial direction, so that the total amount of resin filled in the rotor core 101 can be reduced. Note that, as an example, in the modified example shown in FIG. 7, the size of the communication hole portion 304 in the axial direction is about half the size of the rotor core 101.

[0094] In the above embodiment, the rotor core is provided with the weight-saving holes, but the present invention is not limited to this. In the present invention, the rotor core does not necessarily need to be provided with the weight-saving holes.

[0095] In the above embodiment, the rotor is provided with a resin joint, but the present invention is not limited to this. In the present invention, the rotor does not have to be provided with a resin joint.

[0096] In the above embodiment, the circumferential center line of the communication hole portion and the circumferential center line of the permanent magnet are aligned, but the present invention is not limited to this. In the present invention, the circumferential center line of the communication hole portion and the circumferential center line of the permanent magnet do not have to be aligned (they may be offset in the circumferential direction).

[0097] In the above embodiment, the circumferential center line of the communication hole portion and the circumferential center line of the magnet accommodating hole are aligned, but the present invention is not limited to this. In the present invention, the circumferential center line of the communication hole portion and the circumferential center line of the magnet accommodating hole do not have to be aligned (they may be offset in the circumferential direction).

[0098] In the above embodiment, the circumferential center line of the communicating hole portion and the circumferential center line of the non-magnet hole are aligned, but the present invention is not limited to this. In the present invention, the circumferential center line of the communicating hole portion and the circumferential center line of the non-magnet hole do not have to be aligned (they may be offset in the circumferential direction).

[0099] In the above embodiment, the circumferential width of the connection portion between the communication hole portion and the magnet accommodating hole is 1.4 mm or less, but the present invention is not limited to this. In the present invention, the circumferential width of the connection portion between the communication hole portion and the magnet accommodating hole may be greater than 1.4 mm.

[0100] In the above embodiment, the circumferential width of the connection portion between the communication hole portion and the non-magnet hole is 3.8 mm or less, but the present invention is not limited to this. In the present invention, the circumferential width of the connection portion between the communication hole portion and the non-magnet hole may be greater than 3.8 mm. [Explanation of symbols]

[0101] 2 Magnet housing hole 3 Non-magnet hole 4, 204, 304 Communication hole 20 (Magnet insertion portion of magnet receiving hole) 21 (Magnet receiving hole) magnet fixing resin filling part 21a (Magnet fixing resin filled part) Circumferential end side resin part 21b Radial inner resin portion (of magnet fixing resin filled portion) 100, 200, 300 rotors 101 Rotor core L1 (permanent magnet) center line M Permanent magnet

Claims

1. A permanent magnet; a rotor core including a magnet accommodating hole having a magnet insertion portion into which the permanent magnet is inserted and a magnet fixing resin filled portion into which a resin that fixes the permanent magnet is filled, the rotor core being formed by laminating a plurality of electromagnetic steel plates; The rotor core is a magnet non-accommodating hole arranged radially inside the magnet accommodating hole; the rotor further including a communication hole portion arranged radially inward of the permanent magnet and communicating between the magnet accommodating hole and the magnet non-accommodating hole.

2. The rotor according to claim 1 , wherein the communicating hole portion, the magnet accommodating hole and the magnet non-accommodating hole are formed in a constricted shape in the circumferential direction such that the communicating hole portion is narrower than the magnet accommodating hole and the magnet non-accommodating hole.

3. the magnet fixing resin filling portion has a pair of circumferential end side resin portions provided on both sides in the circumferential direction of the permanent magnet, The rotor according to claim 1 , wherein the communicating hole portion extends radially along a circumferential center line extending radially of the permanent magnet and is positioned circumferentially midway between a pair of the circumferential end side resin portions.

4. the magnet fixing resin filling portion is provided so as to extend in a circumferential direction along an inner surface on the radially inner side of the permanent magnet, and has a radially inner resin portion that connects the communication hole portion and the circumferential end side resin portion, The rotor according to claim 3 , wherein the permanent magnet is disposed inside the magnet accommodating hole so as to be biased radially outward by the radially inner resin portion.

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