Rotor and brushless motor

Abstract

The present invention provides a rotor and a brushless motor that can secure permanent magnets with an appropriate press-fit force while maintaining motor performance and reducing manufacturing costs. The rotor comprises: a cylindrical core body having a cylindrical space formed on the rotation center side; a plurality of magnet receiving hole pairs, each comprising a pair of magnet receiving holes extending axially through the core body and arranged in a V-shape, separating from each other as they approach the stator side of the core body in the radial direction; a plurality of permanent magnets housed and secured in the magnet receiving holes; a protrusion, one provided in each magnet receiving hole, projecting from the q-axis side and the other radial side of the core body along the direction in which the q-axis side surface of the magnet receiving hole extends, and press-fitting against the permanent magnet from the q-axis side and the other radial side; and a protrusion-forming space extending axially through the core body and extending radially from the q-axis side surface along the q-axis side surface.

Description

Technical Field

[0001] The present invention relates to a rotor having permanent magnets arranged inside a core body and a brushless motor including the rotor. Background Art

[0002] Conventionally, so-called IPM (Interior Permanent Magnet) rotors are known, in which permanent magnets are arranged inside the core body. In such rotors, the centrifugal force generated by the rotor's rotation acts on the permanent magnets, causing them to move, potentially causing vibration, noise, or damage to the permanent magnets. Therefore, IPM rotors require that the permanent magnets be securely fixed to the core body, and various methods have been proposed (for example, see Patent Documents 1 to 3).

[0003] For example, Patent Document 1 discloses a rotor core (core body) comprising: a press-fit protrusion that radially projects into a through-hole where a magnet (permanent magnet) is disposed, thereby press-fitting and securing the magnet; and a notch formed at a position radially separated from the magnet across the press-fit protrusion. According to Patent Document 1, the press-fit protrusion is used to press-fit and secure the magnet, while the notch prevents excessive pressure from being applied to the magnet.

[0004] As another example, Patent Document 2 discloses an IPM rotor comprising: a first core sheet having spring plates provided in holes for magnet insertion; and a second core sheet having recesses provided at positions corresponding to the locations of the first core sheet with the spring plates. The IPM rotor is constructed by stacking these core sheets. With this structure, when magnets are inserted into the IPM rotor, the spring plates, bent by the magnets, can be forced into the recesses of the second core sheet, and the magnets can be retained by the restoring force of the spring plates.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 5918958

[0008] Patent Document 2: Japanese Patent Application No. 2018-189822

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2010-252417 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] However, for example, the structure of Patent Document 1 causes excessive press-fitting force, potentially leading to the rotor core being chipped when inserting magnets into it, resulting in the generation of debris. Furthermore, Patent Document 2 employs a structure that stacks core sheets of varying shapes, necessitating rotational stacking and increasing mold costs. Furthermore, the placement of protrusions and recesses can potentially obstruct the flow of magnetic flux, making these configurations crucial for ensuring motor performance.

[0012] It should be noted that as a method of fixing the magnet, a method of using an adhesive without forming a protrusion or the like is also considered. However, the fixing method using an adhesive sometimes requires special equipment for coating, depending on the type of adhesive. In addition, in the case of liquid adhesives, since it takes time to solidify, it is not preferred in terms of achieving improved production efficiency. In addition, generally speaking, since adhesives have a shelf life, attention must also be paid to the management (storage) of the adhesive. This issue may occur in both inner rotor type motors and outer rotor type motors.

[0013] This application was developed in response to this problem, and one of its objectives is to provide a rotor and a brushless motor that can secure permanent magnets with an appropriate press-fit force while maintaining motor performance and reducing manufacturing costs. It should be noted that this application is not limited to this objective, and another objective of this application is to achieve the effects brought about by the various structures shown in the specific embodiments described below, which are not achievable with conventional technologies.

[0014] Solutions to Problems

[0015] (1) The rotor disclosed herein comprises: a cylindrical core body composed of a plurality of laminated cores of the same shape and a cylindrical space formed on the rotation center side; a plurality of magnet receiving hole pairs, each of which includes a pair of magnet receiving holes that are arranged along the axial direction of the core body and are arranged in a V-shape so as to be separated from each other as they approach the side of the core body as the stator side in the radial direction, and are arranged separately along the circumferential direction of the core body; a plurality of permanent magnets that are respectively accommodated and fixed in the magnet receiving holes; a protrusion, each of which is provided with one protrusion and is provided to protrude from the q-axis side as the magnetic pole boundary and the other side of the radial direction along the extension direction of the side surface of the magnet receiving hole on the q-axis side, the protrusion being pressed against the permanent magnet accommodated in the magnet receiving hole from the q-axis side and the other side; and a protrusion forming space that is passed through in the axial direction and extends from the side surface of the magnet receiving hole along the side surface toward the one side in the radial direction.

[0016] (2) Preferably, the protrusion forming surface forming the protrusion forming space is connected to the other side surface forming the other side in the radial direction of the magnet receiving hole.

[0017] (3) Preferably, the length of the protrusion in the width direction perpendicular to the protruding direction is not more than twice the thickness of one sheet of the laminated core.

[0018] (4) Preferably, the length of the protrusion in the width direction is equal to or greater than the plate thickness.

[0019] (5) It is preferable that the length of the protrusion in the protruding direction is longer than the length of the protrusion in the width direction perpendicular to the protruding direction.

[0020] (6) Preferably, the rotor is arranged radially inside the stator, the one side in the radial direction is radially outside, and the other side in the radial direction is radially inside.

[0021] In addition, the motor disclosed herein comprises: the rotor described in (6) above; a shaft portion that rotates integrally with the rotor; and the stator that is fixed to the housing and has a space on the inner diameter side for arranging the rotor and has a coil.

[0022] Effects of the Invention

[0023] According to the disclosed rotor and brushless motor, the protrusions easily elastically deform, allowing the permanent magnets to be fixed to the core body with appropriate press-fit force. Furthermore, the protrusions and the spaces formed by the protrusions do not obstruct the flow of magnetic flux, thereby ensuring performance. Furthermore, since special molds and dedicated equipment are not required, manufacturing costs can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a perspective view of the inner rotor type brushless motor according to the first embodiment.

[0025] Figure 2 It is along Figure 1 Axial cross-sectional view of a brushless motor.

[0026] Figure 3 It shows Figure 1 Exploded perspective view of the rotor and stator of a brushless motor.

[0027] Figure 4 It will Figure 3 An enlarged plan view of portion A viewed in the axial direction is shown.

[0028] Figure 5 Is used to illustrate Figure 4 Diagram of the rotor's magnetic poles and the flow of magnetic flux.

[0029] Figure 6 Is used to illustrate the composition Figure 3 Diagram of the laminated core of the rotor.

[0030] Figure 7 (a) is Figure 6 A magnified view of part B. Figure 7 (b) is shown in Figure 7 (a) shows a rotor core with magnets pressed into it.

[0031] Figure 8 (a) to (d) are figures for explaining comparative examples. Figure 7 (b) corresponds to the figure].

[0032] Figure 9 This is a plan view showing a rotor included in an outer rotor type brushless motor according to a second embodiment, as seen in the axial direction.

[0033] Description of Reference Numerals

[0034] 1 motor (brushless motor)

[0035] 2, 2′ rotor

[0036] 3.3′ stator

[0037] 4. Housing

[0038] 10 Shaft

[0039] 20 rotor core (core body)

[0040] 21 shaft hole

[0041] 22, 22' magnet receiving hole

[0042] 22a Inside side (other side)

[0043] 22b′ Outer side (other side)

[0044] 22c, 22c′ q-axis side (side)

[0045] 23, 23′ magnet receiving hole pair

[0046] 24, 24′ protrusion

[0047] 25, 25′ protrusions form space

[0048] 25f, 25f′ protrusion forming surface

[0049] 27, 27′ magnet

[0050] 28, 28′ magnet pair

[0051] 29 Laminated Core

[0052] C Center of rotation

[0053] L: Protrusion length (length in the protruding direction)

[0054] T Laminated core thickness

[0055] W is the width dimension of the protrusion (length in the width direction). DETAILED DESCRIPTION

[0056] The rotor and brushless motor according to the embodiments are described with reference to the accompanying drawings. The embodiments described below are merely illustrative and are not intended to exclude various modifications or technical applications not explicitly described in the embodiments. The various structures of the embodiments described below can be implemented with various modifications without departing from their main purpose. Furthermore, these can be selected or discarded as needed, or appropriately combined.

[0057] <First embodiment>

[0058] [1.Structure]

[0059] Figure 1 1 is a perspective view of a brushless motor 1 (hereinafter referred to as “motor 1 ”) according to a first embodiment. Figure 2 : is an axial cross-sectional view of the motor 1. The motor 1 of this embodiment is an inner rotor type brushless DC motor, and the motor 1 is composed of a rotor 2 with a shaft 10 fixed thereto and a stator 3 fixed to the housing 4, which forms the outer contour of the motor 1. The housing 4 is a cylindrical shape with both ends open in the axial direction, and one end side ( Figure 2 The end cap 15 is fixed to the opening of the right side of the middle part, and the end cap 15 is fixed to the opening of the right side of the middle part. Figure 2 The front cover 14 is fixed to the opening of the housing 4 (on the left side). It should be noted that the outer shape of the housing 4 in this embodiment is a substantially rectangular parallelepiped, but the shape of the housing 4 is not limited thereto.

[0060] Figure 3 This is a perspective view showing the rotor 2 of this embodiment decomposed from the stator 3, and omitting the shaft 10 and the housing 4. Figure 2 as well as Figure 3 As shown, the stator 3 is a substantially cylindrical member having a space for arranging the rotor 2 on the inner diameter side, and the stator 3 includes: an annular stator core 30, which is press-fitted and fixed to the housing 4; and a coil 32, which is wound around the stator core 30 via an insulating member 31. Figure 1 as well as Figure 2As shown, the stator 3 of this embodiment includes: a power supply input lead 6 connected to the coil 32; a sensor signal input / output lead 7; a lead fixing member 5 supporting the lead 6; and a substrate 8 having a rotation detection element for detecting a signal corresponding to the rotational position of the rotor 2. It should be noted that the structure of the stator 3 is not limited to this; for example, the lead fixing member 5 may be omitted, or a separate member supporting the substrate 8 may be provided.

[0061] The shaft 10 is the rotating shaft that supports the rotor 2 and also functions as an output shaft for extracting the output (mechanical energy) of the motor 1 to the outside. Bearings 11 and 12 are provided at two locations on the shaft 10, across from the rotor 2. In this embodiment, bearing 11 is fixed to the front cover 14 and rotatably supports the middle portion of the shaft 10. Bearing 12 is fixed to the end cover 15 and rotatably supports the end portion of the shaft 10 (the right end in the figure).

[0062] like Figure 2 as well as Figure 3 As shown, the rotor 2 is an IPM (Interior Permanent Magnet) rotor and includes a rotor core 20 (core body) that rotates integrally with the shaft 10 around a rotation center C, and a plurality of magnets 27 (permanent magnets) embedded in the rotor core 20 .

[0063] The plurality of magnets 27 are separately arranged around the circumference of the rotor core 20. Two circumferentially adjacent magnets 27 form one magnet pair 28. In this embodiment, a rotor 2 including 14 magnet pairs 28, that is, 28 magnets 27, is illustrated.

[0064] exist Figure 4 as well as Figure 5 Shown by Figure 3 An enlarged plan view of the portion surrounded by the double-dotted chain line. The two magnets 27 constituting a magnet pair 28 are arranged in a V-shape so as to separate from each other as they approach the side of the rotor core 20 that is the stator 3 side in the radial direction. As described above, in the motor 1 to which the rotor 2 of the present embodiment is applied, the rotor 2 is arranged on the radially inner side of the stator 3. Therefore, the above-mentioned "one side" becomes the "radially outer side of the rotor core 20", and the "other side" that is the opposite side of the "one side" becomes the "radially inner side of the rotor core 20". As Figure 5As shown in the figure, the two magnets 27 constituting a magnet pair 28 are arranged so that the same poles are facing each other. On the other hand, the adjacent magnet pairs 28 are arranged so that the different poles are facing each other. Thus, each magnet pair 28 forms a magnetic pole (N pole or S pole) on the radial outside (i.e., the stator 3 side) and generates a flow of magnetic flux as shown by the thick arrow in the figure. The radial straight line between the two magnets 27 constituting the magnet pair 28 becomes the d-axis as the center of the magnetic pole. In addition, the radial straight line between the adjacent magnet pairs 28 becomes the q-axis as the boundary of the magnetic pole. In Figure 4 、 Figure 5 and the following Figures 6 to 9 In FIG. 1 , the d-axis is represented by a dotted line, and the q-axis is represented by a dashed line.

[0065] Magnet 27 is a rectangular parallelepiped having a length equal to the axial length of rotor core 20 and has rectangular end faces 27f facing one axial end and the other axial end when embedded in rotor core 20. End faces 27f of magnet 27 have short sides 27fa and long sides 27fb.

[0066] The rotor core 20 is formed by stacking a plurality of laminated cores 29 in the axial direction, and has a cylindrical shape with a cylindrical space formed on the rotation center side. Figure 6 In the figure, a plan view and a side view of the laminated core 29 of the present embodiment are arranged. The laminated core 29 is a thin electromagnetic steel plate having an axial hole 21 (the above-mentioned cylindrical space) for fixing the shaft portion 10 on the side of the rotation center C, and all the laminated cores 29 are formed into the same shape. A plurality of magnet receiving holes 22 are axially penetrated around the axial hole 21 of the laminated core 29. The magnet receiving holes 22 are through-holes for receiving and fixing the magnets 27. The plurality of magnet receiving holes 22 are provided in the same number as the number of magnets 27, and are provided corresponding to the plurality of magnets 27 as described above.

[0067] Specifically, the plurality of magnet-receiving holes 22 are arranged separately around the circumference of the rotor core 20, with two circumferentially adjacent magnet-receiving holes 22 forming a magnet-receiving hole pair 23. The two magnet-receiving holes 22 forming a magnet-receiving hole pair 23 are arranged symmetrically about the d-axis in a V-shape, separating from each other as they move radially outward. Positioning holes 26 are formed between circumferentially adjacent magnet-receiving holes 22, separating each magnet-receiving hole 22.

[0068] like Figure 7As shown in (a), the magnet receiving hole 22 of this embodiment is formed into a roughly parallelogram shape when viewed in the axial direction. The magnet receiving hole 22 is formed by two surfaces extending in the axial direction and in a direction roughly perpendicular to the q-axis, and two surfaces extending in the axial direction and tilting in the direction away from the q-axis as they tend to the radial inside. Hereinafter, the radially inner surface (the other side surface) of the two surfaces of the former is referred to as the inner side surface 22a, and the radially outer surface of the two surfaces of the former is referred to as the outer side surface 22b. In addition, the surface (side surface) on the q-axis side of the two surfaces of the latter is referred to as the q-axis side surface 22c, and the surface on the d-axis side of the two surfaces of the latter is referred to as the d-axis side surface 22d.

[0069] The distance between the q-axis side surface 22c and the d-axis side surface 22d is set to be equal to the length of the short side 27fa of the magnet 27. Figure 7 As shown in (b), magnet 27 is arranged between q-axis side surface 22c and d-axis side surface 22d, with the side surface having long side 27fb facing q-axis side surface 22c and d-axis side surface 22d. q-axis side surface 22c and d-axis side surface 22d are wider than inner side surface 22a and outer side surface 22b. Inner side surface 22a and outer side surface 22b are positioned so as not to interfere with the corners of end surface 27f of magnet 27 when magnet 27 is arranged in magnet receiving hole 22. When magnet 27 is inserted into magnet receiving hole 22 of this structure, short side 27fa of magnet 27 is arranged at an angle relative to inner side surface 22a and outer side surface 22b. At this time, a small gap is formed between short side 27fa of magnet 27 and inner side surface 22a, and between short side 27fa of magnet 27 and outer side surface 22b. This gap functions as a flux barrier to control the flow of magnetic flux.

[0070] The rotor 2 is provided with a protrusion 24 for press-fitting and fixing the magnet 27 and a protrusion forming space 25 for forming the protrusion 24. Under the action of the protrusion 24 and the protrusion forming space 25, the magnet 27 is fixed to the rotor core 20 by press-fitting without using an adhesive. Figure 6 As shown, one protrusion 24 and one protrusion forming space 25 are provided in each magnet receiving hole 22 , and the number of protrusion forming spaces 25 is the same as the number of magnet receiving holes 22 and magnets 27 .

[0071] The protrusion 24 is provided protruding from the q-axis side and radially inward of the magnet receiving hole 22 along the extending direction of the q-axis side surface 22c. Figure 7 As shown in (a), the protrusion 24 is provided on the radially inner side of the q-axis side 22c forming the magnet receiving hole 22 in a manner such that a portion of the protrusion 24 enters the inner side of the magnet receiving hole 22 along the extending direction of the q-axis side 22c. Figure 7As shown in (b), when the magnet 27 is accommodated in the magnet receiving hole 22, the protrusion 24 elastically deforms toward the q-axis side and radially inward, and is pressed against the magnet 27 accommodated in the magnet receiving hole 22 from the q-axis side and radially inward. As a result, as shown by the hollow arrow in the figure, the magnet 27 is pressed against the d-axis side surface 22d of the magnet receiving hole 22 and is fixed in the magnet receiving hole 22.

[0072] The protrusion forming space 25 is a hollow space that penetrates the axial direction and extends from the q-axis side surface 22c along the q-axis side surface 22c, and is connected to the magnet receiving hole 22. The protrusion forming space 25 is cut out on the q-axis side at a position radially inward of the front end of the protrusion 24, and then extends radially outward along the extension direction of the q-axis side surface 22c. The protrusion forming space 25 of this embodiment is formed by cutting out from the radially innermost end of the q-axis side surface 22c. Therefore, the protrusion forming surface 25f that forms the protrusion forming space 25 of this embodiment is not connected to the q-axis side surface 22c, but is directly connected to the inner surface 22a of the magnet receiving hole 22. The protrusion 24 is formed by the protrusion forming space 25 and the magnet receiving hole 22.

[0073] like Figure 7 As shown in (a), in the rotor 2 of this embodiment, the length L of the protrusion 24 in the protruding direction (hereinafter referred to as "protruding length L") is longer than the length W of the protrusion 24 in the width direction perpendicular to the protruding direction (hereinafter referred to as "width dimension W"). As a result, the protrusion 24 is easily elastically deformed, and the pressing force does not become too large. In addition, the width dimension W of the protrusion 24 of this embodiment is formed to be the thickness T of a single laminated core 29 (refer to Figure 6 ). The longer the width W of the protrusion 24, the greater the press-fitting force. Therefore, by setting it to be no greater than twice the plate thickness T, excessive press-fitting force can be suppressed. Furthermore, in this embodiment, the width W of the protrusion 24 is set to be greater than the plate thickness T, enabling normal stamping.

[0074] [2. Action, effect]

[0075] (1) The rotor 2 described above is provided with a protrusion 24 projecting along the q-axis side surface 22c of the magnet receiving hole 22, and a protrusion-forming space 25 extending radially outward from the q-axis side surface 22c of the magnet receiving hole 22. In other words, the protrusion 24 is configured such that its protruding direction includes a component in the extension direction of the q-axis side surface 22c, and the protrusion 24 is displaced toward the q-axis side due to the action of the protrusion-forming space 25 extending radially outward along the q-axis side surface 22c. Therefore, the protrusion 24 is easily elastically deformed in a direction perpendicular to the extension direction of the q-axis side surface 22c when viewed axially, i.e., toward the q-axis side and radially inward, thereby optimizing the pressing force when press-fitting the magnet 27. This solves the problem of "chip generation" that occurs when the pressing force is too large. In the rotor 2 , the protrusions 24 and protrusion-forming spaces 25 are located radially inwardly of the magnet housing hole 22 on the q-axis side, thereby preventing magnetic flux from being obstructed and maintaining the performance of the motor 1 .

[0076] Here, as a comparative example, Figure 8 (a) shows a rotor core 50W without a protrusion. Figure 8 As comparative examples, Figures (b) through (d) show rotor cores 50X, 50Y, and 50Z, each having a protrusion provided at a position different from that of the rotor 2 described above. Each of rotor cores 50W, 50X, 50Y, and 50Z is provided with a magnet receiving hole 52 for receiving and accommodating a magnet 57 having the same shape as magnet 27 of the embodiment described above.

[0077] In such Figure 8 When a rotor core 50W without a protrusion, as shown in FIG. 5 (a), is pressed into a fixed magnet (not shown), the shape of the magnet receiving hole 52 is slightly smaller than the outer shape of the magnet (not shown) to provide a desired press-in amount. However, in this case, the press-in force is excessive, resulting in the generation of debris. In contrast, in the rotor 2 (rotor core 20) described above, the shape of the protrusion 24 is refined, thereby optimizing the press-in force as described above, thereby preventing the generation of debris.

[0078] Figure 8 The rotor core 50X shown in (b) is similar to the above-mentioned rotor core 20 in that a protrusion 54X and a protrusion forming space 55X are provided on the q-axis side surface 52c forming the magnet receiving hole 52. However, it is different from the above-mentioned rotor core 20 in that the protrusion forming space 55X extends from the radial outside to the radial inside. The result of simulating the magnetic flux reduction rate of the rotor having this rotor core 50X is that the magnetic flux reduction rate is 0.9%. It should be noted that the magnetic flux reduction rate refers to the rotor core having no protrusion (for example Figure 8The ratio (%) of the reduction in magnetic flux relative to the magnetic flux of the rotor core as shown in (a) is taken as the reference.

[0079] In the case of rotor core 50X, where protrusion-forming spaces 55X extend radially inward from protrusions 54X, as shown by the thick arrows in the figure, the radially outer portion of protrusion-forming spaces 55X overlaps the flow of magnetic flux (the path of magnetic flux). Consequently, protrusions 54X and protrusion-forming spaces 55X obstruct the flow of magnetic flux, increasing the magnetic flux reduction rate and thus degrading motor performance.

[0080] To solve this problem, in the rotor 2, as described above, the protrusion forming space 25 is arranged to extend radially outward from the radially inner side of the protrusion 24 so as not to obstruct the flow of magnetic flux (see FIG. Figure 5 ). Therefore, the same simulation was performed on the rotor 2 having the above-mentioned rotor core 20. As a result, it was found that the magnetic flux reduction rate in the rotor 2 was 0.0%. Therefore, the motor 1 including the rotor 2 can ensure the performance of the motor 1.

[0081] Figure 8 The rotor core 50Y shown in (c) is different from the above-mentioned rotor core 20 in that a protrusion 54Y and a protrusion forming space 55Y are provided on the d-axis side surface 52d forming the magnet receiving hole 52. More specifically, in the rotor core 50Y, the protrusion 54Y and the protrusion forming space 55Y are provided in the radial center portion of the d-axis side surface 52d. The result of simulating the magnetic flux reduction rate for the rotor having this rotor core 50Y is that the magnetic flux reduction rate becomes 1.9%. In this rotor core 50Y, as shown by the thick arrow in the figure, the protrusion 54Y and the protrusion forming space 55Y overlap with the flow of magnetic flux. Therefore, due to the Figure 8 For the same reason as the rotor core 50X in (b), the flow of magnetic flux is obstructed, resulting in reduced motor performance. In contrast, in the rotor 2 described above, the protrusion 24 and the protrusion-forming space 25 are located on the q-axis side of the magnet receiving hole 22 and are configured so as not to obstruct the flow of magnetic flux. Therefore, the performance of the motor 1 can be maintained.

[0082] Figure 8The rotor core 50Z shown in (d) differs from the aforementioned rotor core 20 in that it includes a protrusion 54Z and a protrusion-forming space 55Z on the inner side surface 52a forming the magnet housing hole 52. Simulations of the magnetic flux reduction rate for a rotor having this rotor core 50Z revealed a magnetic flux reduction rate of 0.4%. Furthermore, in this rotor core 50Z, the protrusion 54Z is provided on the inner side surface 52a, which is narrower than the q-axis side surface 52c and the d-axis side surface 52d. Therefore, the length of the protrusion 54Z in the protruding direction cannot be ensured. Consequently, the deformation of the protrusion 54Z cannot be ensured, potentially resulting in excessive press-fitting force. In contrast, in the aforementioned rotor 2 (rotor core 20), the protrusion 24 is provided on the q-axis side surface 22c, which is wider than the inner side surface 22a. This ensures a sufficient protruding length and optimizes the press-fitting force.

[0083] Furthermore, the plurality of laminated cores 29 constituting the rotor core 20 described above all have the same shape, eliminating the need for rotational lamination as described in Patent Document 2. Consequently, there is no increase in mold costs, and manufacturing costs can be suppressed. Furthermore, no adhesive is used to secure the magnets 27 to the rotor core 20, eliminating the drawbacks associated with adhesives, such as the need for drying time, the need for dedicated equipment, and the need to manage the adhesive's expiration date. This is another advantage of the rotor 2 and motor 1 described above.

[0084] (2) In the rotor 2 described above, the protrusion-forming surface 25f forming the protrusion-forming space 25 is connected to the radially inner side surface 22a forming the magnet receiving hole 22. Thus, by providing the protrusion-forming space 25 at the radially innermost side of the magnet receiving hole 22, the flow of magnetic flux is less likely to be obstructed, thereby further ensuring the performance of the motor 1.

[0085] (3) In the rotor 2 and motor 1 described above, the width W of the protrusion 24 is less than or equal to twice the thickness T of one laminated core 29 . This prevents the press-fitting force from becoming excessive, and prevents the generation of chips when the magnet 27 is pressed in.

[0086] (4) Furthermore, since the width dimension W of the protrusion 24 is greater than or equal to the plate thickness T (ie, "T≤W≤2×T"), the laminated core 29 can be formed by ordinary press working without using a special die or the like. This reduces manufacturing costs.

[0087] (5) In the above-described rotor 2 and motor 1 , the protruding length L of the protrusion 24 is longer than the width W, thereby preventing the press-fitting force from becoming excessive and ensuring the elastic force accompanying the elastic deformation of the protrusion 24 .

[0088] [3. Others]

[0089] The structures of the rotor 2 and the motor 1 described in the above embodiment are only examples and are not limited to the above contents. In the above embodiment, the protrusion forming space 25 is formed at the radially innermost end of the q-axis side surface 22c, but the protrusion forming space can also be formed at a position radially outward from this position. That is, it is also possible that the protrusion forming surface forming the protrusion forming space is connected to the inner surface via the q-axis side surface. If the position of the protrusion forming space is on the q-axis side and radially inward of the magnet receiving hole 22, and is a position where the protrusion forming spaces provided in two adjacent magnet receiving holes are not connected to each other, it is not limited to the above contents. In addition, the protrusion length L and width dimension W of the protrusion 24 can also be set to dimensions different from those described above. In addition, the shapes and structures of the stator 3 and the housing 4 are not limited to the above contents.

[0090] <Second embodiment>

[0091] In the first embodiment described above, the motor 1 is exemplified as an inner rotor type brushless DC motor, but the motor to which the rotor of the present invention is applied may also be an outer rotor type brushless DC motor. Figure 9 The figure shows a plan view of the rotor 2' of the second embodiment when viewed from the axial direction. The rotor 2' of the second embodiment is applied to an outer rotor type brushless DC motor (not shown), and is provided with a stator 3' fixed to the motor housing and a shaft (not shown) serving as a rotating shaft supporting the rotor 2' on its inner diameter side. Figure 9 In FIG. 1 , only the outer shape of the stator 3 ′ is shown by a two-dot chain line, and elements corresponding to those described in the first embodiment are denoted by the same numerals with an apostrophe (′) added thereto.

[0092] like Figure 9 As shown, the rotor 2' comprises a cylindrical rotor core 20' (core body) with a cylindrical space formed on the side of the rotation center C; and magnets 27' (permanent magnets) embedded within the rotor core 20'. Furthermore, the rotor 2' includes magnet-receiving holes 22' for receiving the magnets 27'; protrusions 24' for press-fitting and securing the magnets 27'; and protrusion-forming spaces 25' for forming the protrusions 24'. Similar to the rotor core 20 of the first embodiment, the rotor core 20' is constructed by stacking multiple laminated cores in the axial direction.

[0093] Like the magnets 27 of the first embodiment, the magnets 27' are rectangular parallelepiped-shaped, with a length equal to the axial length of the rotor core 20'. A plurality of magnets 27' are provided, each of which is spaced apart and arranged around the circumference of the rotor core 20'. Two circumferentially adjacent magnets 27' form a magnet pair 28'.

[0094] The two magnets 27' that make up a magnet pair 28' are arranged in a V-shape, separating from each other as they approach the radially stator-facing side of the rotor core 20'. In the brushless DC motor of this embodiment, the stator 3' is positioned radially inward of the rotor 2'. Therefore, the "one side" mentioned above refers to the "radially inner side of the rotor core 20'." Furthermore, the "other side," which is the opposite side of the "one side," refers to the "radially outer side of the rotor core 20'."

[0095] The two magnets 27' that make up a magnet pair 28' are arranged with the same poles facing each other. On the other hand, adjacent magnet pairs 28' are arranged with opposite poles facing each other. Thus, a straight line radially between the two magnets 27' that make up a magnet pair 28' becomes the d-axis, which serves as the magnetic pole center. Furthermore, a straight line radially between adjacent magnet pairs 28' becomes the q-axis, which serves as the magnetic pole boundary.

[0096] The magnet-receiving holes 22' are through-holes extending axially through the rotor core 20'. Like the magnet-receiving holes 22 of the first embodiment, they are roughly parallelogram-shaped when viewed axially. The number of magnet-receiving holes 22' provided is the same as the number of magnets 27', with the plurality of magnets 27' arranged correspondingly to the arrangement described above. That is, the plurality of magnet-receiving holes 22' are separately arranged around the circumference of the rotor core 20', with two circumferentially adjacent magnet-receiving holes 22' forming a magnet-receiving hole pair 23'. The two magnet-receiving holes 22' forming a magnet-receiving hole pair 23' are arranged in a V-shape, symmetrically about the d-axis, separating from each other as they move radially inward.

[0097] One protrusion 24 ′ and one protrusion forming space 25 ′ are provided in each magnet receiving hole 22 ′, and the number of protrusions 24 ′ and the number of magnet receiving holes 22 ′ and magnets 27 ′ are the same.

[0098] The protrusion 24' projects from the q-axis side and radially outward of the magnet receiving hole 22' along the direction in which the side surface (q-axis side surface 22c') forming the q-axis side of the magnet receiving hole 22' extends. More specifically, the protrusion 24' projects from the radially outward portion of the q-axis side surface 22c' along the direction in which the q-axis side surface 22c' extends, with a portion of the protrusion 24' protruding into the interior of the magnet receiving hole 22'. Thus, when the magnet 27' is received in the magnet receiving hole 22', the protrusion 24' elastically deforms toward the q-axis side and radially outward, and presses against the magnet 27' received in the magnet receiving hole 22' from the q-axis side and radially outward, thereby securing the magnet 27'.

[0099] The protrusion forming space 25′ is a hollow space that penetrates the axial direction and extends from the q-axis side surface 22c′ along the q-axis side surface 22c′, and is connected to the magnet receiving hole 22′. The protrusion forming space 25′ is cut out on the q-axis side at a position radially outward from the front end of the protrusion 24′, and then extends radially inward along the extension direction of the q-axis side surface 22c′. The protrusion forming space 25′ can also be formed by cutting out from the radially outermost end of the q-axis side surface 22c′. That is, the protrusion forming surface 25f′ that forms the protrusion forming space 25′ is not connected to the q-axis side surface 22c′, but is directly connected to the outer surface 22b′ (the other side) of the magnet receiving hole 22′. The protrusion 24′ is formed by the protrusion forming space 25′ and the magnet receiving hole 22′.

[0100] The aforementioned rotor 2′ and the motor using the rotor 2′ can also achieve the same effects as those of the first embodiment. Specifically, according to the rotor 2′, by providing a protrusion 24′ protruding along the q-axis side surface 22c′ and a protrusion-forming space 25′ extending radially inward from the q-axis side surface 22c′ along the q-axis side surface 22c′, the pressing force when pressing the magnet 27′ can be optimized. Moreover, in the aforementioned rotor 2′, the protrusion 24′ and the protrusion-forming space 25′ are both arranged on the q-axis side and radially outward of the magnet receiving hole 22′, so as not to obstruct the flow of magnetic flux. This prevents a reduction in magnetic flux and ensures the performance of the motor.

[0101] In addition, the protrusion forming surface 25f′ forming the protrusion forming space 25′ is connected to the outer side surface 22b′ forming the radial outer side of the magnet receiving hole 22′. In other words, the protrusion forming space 25′ is arranged at the radial outermost side of the magnet receiving hole 22′, thereby making it difficult to hinder the flow of magnetic flux, thereby further ensuring the performance of the motor.

[0102] If the width of the protrusion 24' (the length of the protrusion 24' in the width direction perpendicular to the protruding direction) is set to be no more than twice the thickness of a single laminated core, it is possible to prevent excessive press-fitting force and prevent the generation of chips when the magnet 27' is pressed in. Furthermore, if the width of the protrusion 24' is set to be greater than the thickness of a single laminated core, each laminated core can be formed by conventional stamping without the use of special dies or the like.

[0103] Furthermore, if the protruding length of the protrusion 24' (the length of the protrusion 24' in the protruding direction) is longer than the width of the protrusion 24', it is possible to prevent excessive pressing force and ensure elastic force accompanying elastic deformation of the protrusion 24'.

[0104] The configurations of the rotor 2' and the motor to which the rotor 2' is applied are merely examples and are not limited to the above-described configurations. Various modifications applicable to the rotor 2 of the first embodiment may be applied to the rotor 2'.

Claims

1. A rotor, characterized in that: have: A cylindrical core body, which is composed of a plurality of laminated cores of the same shape and has a cylindrical space formed on the rotation center side; a plurality of magnet receiving hole pairs, each comprising a pair of magnet receiving holes extending axially through the core body and arranged in a V-shape so as to separate from each other as they approach the stator side in the radial direction of the core body, and spaced apart in the circumferential direction of the core body; a plurality of permanent magnets housed and fixed in the magnet receiving holes so that a d-axis serving as a magnetic pole center is formed between the pair of magnet receiving holes included in each magnet receiving hole pair and a q-axis serving as a magnetic pole boundary is formed between the magnet receiving hole pairs adjacent to each other in the circumferential direction; a protrusion, one protrusion provided in each magnet receiving hole, and protruding from the q-axis side and the other radial side along the extending direction of the side surface of the magnet receiving hole on the q-axis side, the protrusion being pressed against the permanent magnet received in the magnet receiving hole from the q-axis side and the other side; as well as The protrusion forms a space that penetrates in the axial direction and extends from the side surface of the magnet receiving hole along the side surface toward the one side in the radial direction.

2. The rotor according to claim 1, characterized in that The protrusion forming surface forming the protrusion forming space is connected to the other side surface forming the magnet receiving hole on the other side in the radial direction.

3. The rotor according to claim 1 or 2, characterized in that: The length of the protrusion in the width direction perpendicular to the protruding direction is not more than twice the thickness of one sheet of the laminated core.

4. The rotor according to claim 3, characterized in that The length of the protrusion in the width direction is equal to or greater than the plate thickness.

5. The rotor according to claim 1 or 2, characterized in that: The length of the protrusion in the protruding direction is longer than the length of the protrusion in the width direction perpendicular to the protruding direction.

6. The rotor according to claim 1 or 2, characterized in that: The rotor is arranged radially inward of the stator. The one side in the radial direction is a radially outer side, and the other side in the radial direction is a radially inner side.

7. A brushless motor, characterized in that: have: The rotor according to claim 6; a shaft portion that rotates integrally with the rotor; and The stator is fixed to the housing, has a space on the inner diameter side for arranging the rotor, and has a coil.

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