Rotor structure of rotary electrical machine

Abstract

To provide a rotor structure for a rotary electrical machine capable of adjusting a rotational balance of the rotor by a rotor core.SOLUTION: A rotor of a motor 10 has a rotor core 16 arranged on an outer circumferential surface of a rotor shaft, and a rotor core 12 is formed by stacking a plurality of electromagnetic steel sheets 20. A plurality of hole portions 34 are formed on the electromagnetic steel sheets 20, and the hole portions 34 form an oil flow path 32 in the rotor core 16. Additionally, in the electromagnetic steel sheets 20, protrusion portions 34 are formed on the hole portions 34, and protrusion portions 40 protrude into the hole portions 34 from the outside in a radial direction of the electromagnetic steel sheets 20. Thus, the magnetic steel sheets 20 can adjust the rotational balance of the rotor 12 by adjusting the position of the center of gravity with the hole portions 34 in which the protrusion portions 40 are provided, and the number of protrusion portions 40 provided in the hole portions 34.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotor structure for a rotating electrical machine. [Background technology]

[0002] In an electric motor, cooling oil is used to cool the rotor shaft and rotor core. For example, in Patent Document 1, a hollow portion extending in the axial direction is provided in the rotor shaft, and the rotor shaft is cooled by oil supplied into the hollow portion.

[0003] In addition, in Patent Document 1, when eliminating imbalance in the rotational balance of a rotor assembly in which the rotor shaft and rotor core are integrated, the rotational balance of the rotor assembly is measured, and the number, formation positions and hole diameter of oil holes formed through the rotor shaft are adjusted based on the results of the rotational balance measurement. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-150614 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the rotor core is formed by laminating electromagnetic steel plates, and the rotor core is provided with oil flow paths that penetrate the electromagnetic steel plates in the rotor axial direction, thereby improving cooling efficiency.

[0006] On the other hand, in a rotor (rotor assembly) where the rotor core is integrated with the rotor shaft, the weight balance of the rotor core changes due to the formation of oil flow paths in the rotor core. Since changes in the weight balance of the rotor affect the rotational balance, there is room for improvement in adjusting the rotational balance.

[0007] The present invention has been made in consideration of the above-mentioned facts, and aims to provide a rotor structure for a rotating electric machine that enables adjustment of the rotational balance of a rotor integrated with a rotor core using a rotor core. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the rotor structure of the rotating electric machine of this embodiment includes a rotor shaft of a rotor that rotates relative to a stator in a rotating electric machine, a rotor core of the rotor in which a plurality of electromagnetic steel plates formed in a ring shape are stacked and attached to the outer peripheral surface of the rotor shaft so as to be rotatable integrally with the rotor shaft, holes formed through each of the electromagnetic steel plates and extending in the axial direction of the rotor shaft in the rotor core to form an oil passage through which cooling oil flows, and protrusions in the electromagnetic steel plates that protrude radially inward from the radially outer outer peripheral edge of the hole portions and that, when positioned within the opening of the hole portions, adjust the position of the center of gravity of the electromagnetic steel plates depending on the hole portions that are positioned and the number of holes that are positioned, thereby adjusting the rotational balance of the rotor.

[0009] In the rotor structure of the rotating electric machine of the present aspect, the rotor includes a rotor shaft and a rotor core that rotates integrally with the rotor shaft, and the rotor rotates relative to the stator in the rotating electric machine. The rotor core is made of laminated annular electromagnetic steel plates.

[0010] The electromagnetic steel plates have holes formed therethrough, and in the rotor core, the electromagnetic steel plates are stacked so that the holes of the multiple electromagnetic steel plates are connected together and an oil passage for cooling oil extends in the axial direction of the rotor shaft.

[0011] Here, the electromagnetic steel sheet has a protrusion that protrudes radially inward from the outer peripheral edge on the radial outside of the hole and is disposed within the opening of the hole, whereby the protrusion is formed protruding into the hole, increasing the contact area with the cooling oil, improving the efficiency of heat exchange between the electromagnetic steel sheet and the cooling oil, and enabling effective cooling by the cooling oil.

[0012] In addition, the electromagnetic steel sheet protrudes radially inward from the outer peripheral edge on the radial outside of the hole and is disposed within the opening of the hole. In the electromagnetic steel sheet, the protrusion protruding from the hole changes the position of the center of gravity, changing the weight balance, and the protrusion allows weight adjustment (adjustment of the weight balance).

[0013] The center of gravity of the magnetic steel sheet is adjusted according to the holes in which the protrusions are disposed and the number of protrusions disposed in the holes, thereby adjusting the rotational balance of the rotor. Effect of the Invention

[0014] According to the present invention, by providing protrusions in holes in an electromagnetic steel sheet for forming a flow path for cooling oil in a rotor core, it is possible to improve the cooling efficiency by the cooling oil. Also, the present invention has an effect that the rotational balance of the rotor can be adjusted by adjusting the weight balance by the holes in which the protrusions are provided in the electromagnetic steel sheet and the number of protrusions in the holes. [Brief description of the drawings]

[0015] [Figure 1] 2 is a cross-sectional view of a main part of the motor according to the embodiment, taken in a radial direction. FIG. [Diagram 2] 1A is a front view showing an outline of an electromagnetic steel sheet as viewed in the axial direction, and FIG. 1B is a front view showing an example of a main part of the electromagnetic steel sheet. [Diagram 3] 4(A) to 4(C) are front views of the electromagnetic steel sheet as viewed in the axial direction. [Figure 4] 1A and 1B are schematic diagrams each showing an example of a protrusion. [Diagram 5] FIG. 2 is a perspective view showing a schematic outline of a rotor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. This embodiment will be described by taking as an example an electric motor (motor) 10 as a rotating electric machine to which the rotor structure of the present invention is applied. The motor 10 is used in vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell electric vehicles (FCEVs), and battery electric vehicles (BEVs). Fig. 1 shows a cross-sectional view of a main part of the motor 10 according to this embodiment as viewed in the radial direction.

[0017] 1, motor 10 includes rotor 12 (rotor assembly), and in motor 10, rotor 12 is housed together with a stator in a case (both not shown), and rotor 12 is supported so as to be rotatable relative to the stator. In the drawing, the axial direction of rotor 12 etc. in motor 10 is indicated by arrow L, and the radially outer side of rotor 12 is indicated by arrow R.

[0018] The rotor 12 includes a rotor shaft 14 and a rotor core 16. The rotor shaft 14 has a generally cylindrical shape (approximately cylindrical shape) with a hollow interior, and both ends of the rotor shaft 14 in the axial direction are rotatably supported by bearings (not shown) and attached to a case via the bearings.

[0019] The hollow interior of rotor shaft 14 serves as oil reservoir 18 in which oil is stored as a cooling oil (refrigerant), and oil reservoir 18 extends in the axial direction within rotor shaft 14. In motor 10, oil is supplied to oil reservoir 18 of rotor shaft 14 from an oil supply source (not shown).

[0020] Further, in rotor shaft 14, ejection holes 18A are formed at an intermediate position in the axial direction (a position corresponding to the center position of rotor core 16 in the axial direction), and ejection holes 18A are formed radially penetrating the outer periphery of rotor shaft 14. This allows oil in oil reservoir 18 in rotor shaft 14 to flow out from ejection holes 18A.

[0021] The rotor core 16 has a generally cylindrical outer shape and is disposed on the outer circumferential surface of the rotor shaft 14. The rotor core 16 is fitted onto the rotor shaft 14 and attached so as to rotate integrally with the rotor shaft 14.

[0022] A plurality of electromagnetic steel sheets 20 are used as core members in rotor core 16, and in rotor core 16, electromagnetic steel sheets 20 are laminated along the axial direction of rotor shaft 14. Fig. 2(A) shows the electromagnetic steel sheets 20 in a plan view as viewed in the axial direction, and Fig. 2(B) shows an example of a main portion of electromagnetic steel sheet 20 in a front view.

[0023] 2, the electromagnetic steel sheet 20 is formed in an annular (disk-like) shape with a required thickness dimension (hereinafter referred to as thickness) t, and an opening 22 having an inner diameter corresponding to the outer diameter of the rotor shaft 14 is formed through the axial center of the electromagnetic steel sheet 20. The inner peripheral surface of each opening 22 of the electromagnetic steel sheet 20 is in close contact with the outer peripheral surface of the rotor shaft 14.

[0024] 1, a substantially disk-shaped flange portion 24 is integrally formed on rotor shaft 14 at an axially intermediate portion thereof, at a position corresponding to one axial end side of rotor core 16, and flange portion 24 has a larger diameter than rotor shaft 14. In addition, a disk-shaped retainer 26 is attached to rotor shaft 14 at a predetermined position corresponding to the other axial end side of rotor core 16 (the opposite side to flange portion 24).

[0025] The clamp 26 has approximately the same diameter as the flange portion 24. Furthermore, the ejection hole 18A formed in the rotor shaft 14 is disposed between the flange portion 24 and the clamp 26. That is, the flange portion 24 and the clamp 26 are disposed on the rotor shaft 14 so as to sandwich the ejection hole 18A therebetween.

[0026] The rotor core 16 has laminated electromagnetic steel sheets 20 arranged between a flange portion 24 and a clamp 26, and is held by the rotor shaft 14 between the flange portion 24 and the clamp 26, so that it rotates integrally with the rotor shaft 14.

[0027] 1 and 2(A), permanent magnets 28 are disposed on the radially outer portion of rotor core 16. The longitudinal direction of permanent magnets 28 is aligned with the axial direction of rotor core 16, and permanent magnets 28 are disposed straddling one side to the other side of rotor core 16 in the axial direction.

[0028] As shown in FIG. 2(A), the rotor core 16 is provided with a plurality of sets of permanent magnets 28 (eight sets in this embodiment). A plurality of magnet mounting portions 30 are formed on the outer periphery of the electromagnetic steel sheet 20, and the magnet mounting portions 30 are grouped into two magnet mounting portions 30A, 30B, so that eight sets of magnet mounting portions 30 (30A, 30B) are formed at predetermined intervals in the circumferential direction. The magnet mounting portions 30 are elongated holes that penetrate the electromagnetic steel sheet 20 in the axial direction of the rotor core 16 and open. In addition, the longitudinal direction of each set of magnet mounting portions 30A, 30B is inclined at a required angle with respect to the radial direction of the electromagnetic steel sheet 20 so that the adjacent sides of the magnet mounting portions 30A, 30B are located on the radially inner side of the electromagnetic steel sheet 20.

[0029] The permanent magnets 28 are paired, that is, permanent magnets 28A and 28B, with the permanent magnet 28A loaded in the opening of magnet loading portion 30A and the permanent magnet 28B loaded in the opening of magnet loading portion 30B. As a result, the rotor core 16 has a plurality of pairs of permanent magnets 28 (28A, 28B) arranged in the circumferential direction on the outer periphery.

[0030] In motor 10, an armature coil (not shown) is arranged on the stator, and in motor 10, when the required power is supplied to the armature coil, a magnetic force is generated and received by each set of permanent magnets 28A, 28B, and this magnetic force is used as a driving force to rotate rotor 12.

[0031] On the other hand, as shown in FIG. 1, rotor core 16 is formed with a plurality of oil flow paths 32 as oil passages through which oil flows, and in rotor core 16, oil flow paths 32 extend from one end to the other end in the axial direction of rotor core 16.

[0032] 2(A) and 2(B), a plurality of holes 34 are formed in the electromagnetic steel sheet 20. The holes 34 are arranged at predetermined intervals in the circumferential direction on the radially inner side between pairs of magnet mounting portions 30A and 30B adjacent in the circumferential direction of the electromagnetic steel sheet 20, and each of the holes 34 is opened by penetrating the electromagnetic steel sheet 20 in the axial direction of the rotor core 16.

[0033] As a result, eight holes 34 are arranged in the electromagnetic steel sheet 20, and the intervals between adjacent holes 34 in the circumferential direction (the intervals between the central positions along the circumferential direction of the electromagnetic steel sheet 20) are set to the same angle (45° in this embodiment). In the following description, when distinguishing between the holes 34, they are referred to as holes 34A to 34H.

[0034] In rotor core 16, a plurality of oil flow paths 32 each continuing in the axial direction are formed by stacking adjacent magnetic steel sheets 20 so that holes 34 (for example, holes 34A) overlap each other between adjacent magnetic steel sheets 20. As a result, eight oil flow paths 32 are formed in rotor core 16.

[0035] 1, an oil flow passage 36 and a branch passage 38 are formed in an axial intermediate portion 16A of rotor core 16. The oil flow passage 36 has an opening on the radial inner side of rotor core 16 opposed to the opening of ejection hole 18A on the outer periphery of rotor shaft 14. In addition, branch passage 38 branches off from oil flow passage 36 in the radial intermediate portion of rotor core 16, and the branch passage 38 opens to oil flow passage 32 on the side opposite to oil flow passage 36.

[0036] In the rotor 12, ejection holes 18A are formed in the rotor shaft 14 corresponding to each of the oil flow paths 32 of the rotor core 16, and oil flow paths 36 and branch paths 38 are formed in the rotor core 16. As a result, in the rotor 12, the oil reservoir 18 of the rotor shaft 14 and each of the oil flow paths 32 of the rotor core 16 are in communication with each other.

[0037] In the rotor core 16, the electromagnetic steel sheets 20 laminated in the intermediate portion 16A are formed with cuts, holes, etc. for forming the oil flow passages 36 or the branch passages 38, as well as the hole portions 34. FIGS. 3(A) to 3(C) show plan views of the main portions of the electromagnetic steel sheets 20. FIG. 3(A) shows the electromagnetic steel sheets 20 that are disposed on the outer side in the axial direction (stacking direction) of the intermediate portion 16A of the rotor core 16. FIG. 3(B) shows the electromagnetic steel sheets 20 (hereinafter referred to as electromagnetic steel sheets 20A) in which the branch passages 38 are provided in the intermediate portion 16A, and FIG. 3(C) shows the electromagnetic steel sheets 20 (hereinafter referred to as electromagnetic steel sheets 20B) in which the oil flow passages 36 are provided in the intermediate portion 16A.

[0038] 3(A) to 3(C), the holes 34 formed in the electromagnetic steel sheet 20 are elongated holes whose longitudinal direction is in the circumferential direction of the electromagnetic steel sheet 20. Moreover, in each of the holes 34, the radially outer side is formed so as to follow the same circumference centered on the axis of the electromagnetic steel sheet 20 (see FIG. 2(A)).

[0039] 3(C), in the middle of rotor core 16, electromagnetic steel sheet 20C provided at a position corresponding to oil flow path 36 has hole 34 and substantially rectangular cutout 34B formed radially inward of hole 34. In rotor core 16, one or more electromagnetic steel sheets 20B are stacked to form oil flow path 36 that opens radially inward (toward rotor shaft 14).

[0040] 3(B), a hole 34A is formed by expanding the hole 34 radially inward in the electromagnetic steel sheet 20B that is laminated on the axially outer side of the electromagnetic steel sheet 20. The radially inner portion of the hole 34A in the electromagnetic steel sheet 20B overlaps with the radially outer portion of the cutout portion 34B in the electromagnetic steel sheet 20B.

[0041] As a result, in rotor core 16, one or more electromagnetic steel sheets 20C are stacked to form an oil flow path 36 extending from opening 22 to the radial middle portion. In addition, in rotor core 16, one or more electromagnetic steel sheets 20B are stacked between electromagnetic steel sheets 20A and 20C to form a branch path 38 extending from oil flow path 32 to oil flow path 36, and branch path 38 connects oil flow path 32 and oil flow path 36.

[0042] Incidentally, a protrusion 40 is formed in the hole 34 of the electromagnetic steel sheet 20. As shown in Figures 2(A) and 2(B), the protrusion 40 protrudes from the peripheral edge of the hole 34 in the electromagnetic steel sheet 20 into the opening of the hole 34, and the protrusion 40 protrudes radially inward from the peripheral edge of the hole 34 on the radially outer side of the electromagnetic steel sheet 20. In other words, the protrusion 40 protrudes into the opening of the hole 34 using the peripheral edge of the hole 34 on the side away from the center of the electromagnetic steel sheet 20 as a base.

[0043] The protrusion 40 is formed in at least one hole 34 (at least one of holes 34A to 34H) in the electromagnetic steel sheet 20, and may be formed in all holes 34. Furthermore, when the protrusion 40 is formed in the hole 34, the number of protrusions 40 may be one or more. Schematic diagrams of the protrusion 40 are shown in Figures 4(A) and 4(B).

[0044] The thickness of the protrusion 40 is the same as the thickness (sheet thickness) t of the electromagnetic steel sheet 20. Moreover, the protrusion 40 preferably has a shape in which the width dimension decreases toward the protruding direction (toward the radial inside of the electromagnetic steel sheet 20).

[0045] As shown in Fig. 4(A), a substantially triangular protrusion 40A can be used as the protrusion 40. As shown in Fig. 4(B), a substantially trapezoidal protrusion 40B can be used as the protrusion 40.

[0046] When the width dimension of the base (or lower base) of protrusions 40A, 40B is defined as base width A, base width A is set to be at least twice the sheet thickness t of electromagnetic steel sheet 20 (A≧2·t). When the protrusion height dimension of protrusions 40A, 40B protruding radially inward is defined as protrusion height B, protrusion height B is set to be at least twice the sheet thickness t of electromagnetic steel sheet 20 (B≧2·t).

[0047] In the electromagnetic steel sheet 20, by forming the protrusions 40 in the holes 34, the weight increases according to the unit weight (weight density) of the electromagnetic steel sheet 20, the area of ​​the protrusions 40, and the thickness dimension (hereinafter referred to as thickness) of the protrusions 40. Also, in the electromagnetic steel sheet 20, by forming the protrusions 40 in any one of the holes 34, the position of the center of gravity moves to the side of the hole 34 where the protrusions 40 are formed (radially outward), and the weight balance, which is the balance of the position of the center of gravity with respect to the designed central position, changes.

[0048] Thus, in the electromagnetic steel sheets 20, the weight balance is adjusted by whether or not protrusions 40 are provided in the holes 34, the number of protrusions 40 if protrusions 40 are provided in the holes 34, the base width A, and the protrusion height B. In the rotor 12, the rotational balance is adjusted by adjusting the weight balance of the electromagnetic steel sheets 20 in the rotor core 16. In the rotor 12, the weight balance of each of the electromagnetic steel sheets 20 is adjusted so as to obtain the required rotational balance.

[0049] Next, the operation of this embodiment will be described. In the motor 10, a plurality of permanent magnets 28 (multiple sets of permanent magnets 28A, 28B) are arranged in the rotor core 16 of the rotor 12, and a plurality of armature coils are arranged in the stator. Therefore, in the motor 10, when a required amount of power is supplied to each of the armature coils, the rotor 12 (rotor shaft 14) is rotated relatively, and a driving force corresponding to the rotational force of the rotor 12 is output from the output shaft connected to the rotor shaft 14.

[0050] Furthermore, rotor shaft 14 is provided with oil reservoir 18, to which oil is supplied from an oil supply source. The oil in oil reservoir 18 flows while being rotated by the rotation of rotor shaft 14. For this reason, the oil in oil reservoir 18 flows into ejection hole 18A of rotor shaft 14 due to centrifugal force or the like, is supplied from oil flow path 36 through branch path 38 to oil flow path 32, and flows in the axial direction of rotor core 16 through oil flow path 32.

[0051] As a result, in the motor 10, in the rotor core 16 of the rotor 12, each of the electromagnetic steel sheets 20 is cooled by the oil in the oil flow paths 32, and the rotor core 16 is cooled.

[0052] Incidentally, in the motor 10, the center of gravity of the rotor 12 is the center of rotation, which enables the rotor 12 to rotate smoothly. However, if the center of gravity (center of gravity axis) of the rotor 12 is misaligned with the center of rotation (center of rotation axis), the rotation balance is lost and smooth rotation may be hindered.

[0053] In rotor 12, rotor core 16 is disposed on the outer periphery of rotor shaft 14, and rotor shaft 14 and rotor core 16 rotate integrally. Rotor core 16 is formed by laminating a plurality of electromagnetic steel sheets 20. For this reason, the rotational balance of rotor 12 affects the weight balance of the electromagnetic steel sheets 20, and the rotational balance of rotor 12 can be adjusted by adjusting the weight balance of each electromagnetic steel sheet 20.

[0054] The electromagnetic steel sheet 20 has a plurality of holes 34 formed along the circumferential direction, and the holes 34 are formed at equal intervals along the circumferential direction of the electromagnetic steel sheet 20. Furthermore, the electromagnetic steel sheet 20 has a protrusion 40 formed in at least one of the plurality of holes 34.

[0055] Fig. 5 is a schematic diagram showing an outline of the rotor 12, and in Fig. 5, the center of gravity (center axis of gravity) Ps before adjustment of the rotational balance (before weight adjustment) is inclined with respect to the design center axis (center in design) Po. In this case, as shown in Fig. 2(A), the electromagnetic steel sheet 20 has a plurality of (e.g., three) protrusions 40 formed in each of the holes 34.

[0056] 2(A), in the case where the center of gravity Ps in the electromagnetic steel sheet 20 is shifted toward the hole portion 34A with respect to the designed center of rotation Po, the center of gravity Ps can be moved radially inward with respect to the hole portion 34A by reducing (e.g., by cutting) the number of protrusions 40 formed in the hole portion 34A, thereby making it possible to bring the center of gravity Ps closer to the designed center of rotation Po. In this case, by increasing the number of protrusions 40 to be reduced, the center of gravity Ps can be brought closer to the designed center Po.

[0057] By adjusting the center of gravity Ps of each of the plurality of electromagnetic steel sheets 20 so that it overlaps with the design center of rotation Po, in the rotor 12, the center of gravity Ps can be overlapped with the design center of rotation Po, and the rotational balance is adjusted. As a result, in the electromagnetic steel sheet 20, at least one protrusion 40 is formed in at least one hole 34 of the plurality of holes 34A, and in a rotor using this electromagnetic steel sheet 20, the rotational balance is adjusted by adjusting the protrusion 40. Note that in the rotor 12, in addition to adjusting the protrusion 40 in the electromagnetic steel sheet 20, the length (axial length) along the axial direction of the rotor shaft 14 and the rotor core 16 may be adjusted by cutting or the like.

[0058] On the other hand, in the electromagnetic steel sheet 20, the projections 40 are formed in the holes 34, so that the outer periphery of the holes 34 becomes longer. As a result, the contact area of ​​the electromagnetic steel sheet 20 with the oil flowing through the holes 34 becomes larger compared to a case in which the projections 40 are not provided. As a result, the contact area of ​​the electromagnetic steel sheet 20 with the oil is increased, improving the cooling efficiency by the oil, i.e., the efficiency of heat exchange between the electromagnetic steel sheet 20 and the oil, and each of the permanent magnets 28 arranged in the electromagnetic steel sheet 20 can be effectively cooled.

[0059] In the present embodiment, the motor 10 has been described as an example. However, the rotating electric machine is not limited to an electric motor such as the motor 10, and may be a generator or the like, or may be a motor generator that functions as both an electric motor and a generator. [Explanation of symbols]

[0060] 10 Motor (rotating electric machine) 12 Rotor 14 rotor shaft 16 Rotor core 18 Oil Reservoir 20(20A, 20B, 20C) Electrical steel plate 28(28A, 28B) Permanent magnet 32 Oil flow path (oil passage) 34(34A~34H) Hole 40(40A, 40B) Protrusion

Claims

[Claim 1] a rotor shaft of a rotor that rotates relative to a stator in a rotating electric machine; a rotor core of the rotor, which is made of a plurality of stacked annular electromagnetic steel plates and is attached to an outer circumferential surface of the rotor shaft so as to be integrally rotatable with the rotor shaft; a hole portion formed through each of the electromagnetic steel plates and extending in the axial direction of the rotor shaft in the rotor core to form an oil passage through which cooling oil flows; a protrusion portion that protrudes radially inward from an outer peripheral edge of the hole portion on the electromagnetic steel sheet in the radial direction and that, when placed in an opening of the hole portion, adjusts a center of gravity position of the electromagnetic steel sheet according to the hole portion and the number of the holes to be placed, thereby adjusting the rotational balance of the rotor; A rotor structure of a rotating electric machine comprising:

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