External-type rotary electric machine, hoisting machine, and elevator

Abstract

To improve cooling performance of a stator 20 by enhancing thermal conductivity of a stator frame 10 without increasing the number of components.SOLUTION: An external-type rotary electric machine 100 includes: a stator frame 10; a stator 20 mounted on the stator frame 10; a shaft 30 fixed on the stator frame 10; and a rotor 40 disposed on an outer circumference of the shaft 30 relative to the stator 20. The stator 20 includes a stator core 21 and a coil 22. The stator frame 10 includes: a recessed portion 13 formed around the shaft 30 and recessed in an axial direction of the shaft 30; a first portion 11 located between the recessed portion 13 and the stator core 21 and being in contact with the stator core 21; a second portion 12 located between the recessed portion 13 and the shaft 30 and being in contact with the shaft 30; and a rib 15 formed in the recessed portion 13 and connecting the first portion 11 and the second portion 12. The rib 15 is integrally formed with the first portion 11 and the second portion 12 and being disposed at a position to overlap the stator core 21.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an outer rotor type rotating electric machine, a hoist, and an elevator. [Background technology]

[0002] An elevator hoist is a machine that integrates a motor (rotating electric machine) that serves as the driving force, a sheave that winds up the rope, and a brake that stops the sheave. The sheave rotates together with a drum that is integrated with the motor rotor. The brake is attached to a frame that covers the motor stator.

[0003] When a traction machine is operated by passing current through a motor, losses occur in the stator and rotor that make up the motor, causing the coils and core to heat up. Coils are usually made by winding copper wire with an insulating coating around a core, and if the temperature rise caused by heat generation in the coil or core causes the temperature of the coil's insulating coating to exceed its withstand temperature, it can damage the coil or cause the motor itself to fail.

[0004] Patent Document 1, for example, is an example of a technology relating to heat dissipation from a motor.

[0005] Claim 1 of Patent Document 1 states, "An outer rotor type rotating electric machine having a shaft, a rotor frame rotatable around the axial center of the shaft, a rotor having a rotor core and permanent magnets attached to the inner peripheral side of the rotor frame, a stator frame provided around the shaft, and a stator having a stator core and coils attached to the stator frame and disposed on the inner diameter side of the rotor with a predetermined gap between it and the permanent magnets, wherein the outer rotor type rotating electric machine has heat dissipation fins extending from the inside of the stator beyond the outer surface of the stator frame in parallel to the axis, and the heat dissipation fins are fixed on the outside of the stator frame."

[0006] Furthermore, Figure 1 and the abstract of Patent Document 1 state that "the heat dissipation fins are attached to the outer surface of the stator frame. This simplifies the attachment of the heat dissipation fins and also improves cooling performance by promoting heat dissipation through the fin heat dissipation section." [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-43693 Summary of the Invention [Problem to be solved by the invention]

[0008] However, a structure in which external heat dissipation fins (15) are attached to the outer surface of the stator frame (8), as shown in Figure 1 of Patent Document 1, increases the number of parts, size, and weight, which not only increases the cost of the machine but also poses the problem of difficulty in installation and transportation within a hoistway when used as an elevator hoist.In addition, because the external heat dissipation fins (15) and the stator frame (8) are separate bodies, it is difficult to completely eliminate the gap between them, which poses a problem of limitations on improving thermal conductivity.

[0009] The problem to be solved by the present invention is to provide an outer rotor type rotating electric machine, a hoist, and an elevator in which the thermal conductivity of the stator frame is increased without increasing the number of parts, and the cooling performance of the stator is improved. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the outer rotor type rotating electric machine of the present invention is an outer rotor type rotating electric machine having a stator frame, a stator attached to the stator frame, a shaft fixed to the stator frame, and a rotor arranged on the outer peripheral side of the shaft than the stator, wherein the stator has a stator core and a coil, and the stator frame has a recess formed around the shaft and recessed in the axial direction of the shaft, a first part located between the recess and the stator core and in contact with the stator core, a second part located between the recess and the shaft and in contact with the shaft, and a rib formed in the recess and connecting between the first part and the second part, and the rib is formed integrally with the first part and the second part and is arranged in a position overlapping with the stator core.

[0011] The hoist of the present invention is characterized by having the above-mentioned external rotor type rotating electric machine, a drum that rotates integrally with the rotor around the axis, a sheave provided on the drum for winding a rope around the outside, and a brake for suppressing the rotation of the drum.

[0012] The elevator of the present invention is characterized by having the above-mentioned hoisting machine, the rope wound around the sheave of the hoisting machine, and a car connected to the rope. [Effects of the Invention]

[0013] According to the present invention, it is possible to realize an outer rotor type rotating electric machine, a traction machine, and an elevator in which the thermal conductivity of the stator frame is increased without increasing the number of parts, and the cooling performance of the stator is improved. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view of a half of an axial plane of a hoisting machine employing an outer rotor type rotating electric machine according to a first embodiment of the present invention; [Figure 2] FIG. 2 is a front view of a hoisting machine employing an outer rotor type rotating electric machine according to the first embodiment. [Figure 3]1 is a first quadrant cross-sectional view of a plane perpendicular to the axial direction of a hoisting machine that employs an outer rotor type rotating electric machine according to a first embodiment of the present invention; [Figure 4] FIG. 10 is a front view of a hoisting machine employing an outer rotor type rotating electric machine according to a second embodiment. [Figure 5] FIG. 11 is a front view of a hoist employing an outer rotor type rotating electric machine according to a third embodiment. [Figure 6] FIG. 11 is a half cross-sectional view of an axial plane of a hoisting machine employing an outer rotor type rotating electric machine according to a third embodiment. [Figure 7] FIG. 10 is a front view of a hoist employing an outer rotor type rotating electric machine according to a fourth embodiment. [Figure 8] FIG. 10 is a diagram illustrating the schematic configuration of an elevator according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing and each embodiment, the same or similar components are designated by the same reference numerals, and redundant explanations will be omitted. [Example]

[0016] FIG. 1 is a cross-sectional view of half of the axial plane of a hoist employing an outer rotor type rotating electric machine of the first embodiment. FIG. 2 is a front view of a hoist employing an outer rotor type rotating electric machine of the first embodiment. FIG. 3 is a first quadrant cross-sectional view of a hoist employing an outer rotor type rotating electric machine of the first embodiment in a plane perpendicular to the axial direction. The arrows at the bottom of the drawing indicate a coordinate system common to the following drawings. FIG. 3 corresponds to a cross-sectional view of the A-A' cross section in FIG. 1 as seen from the positive direction of the Z axis.

[0017] The external rotor type rotating electric machine 100 of this embodiment has a stator frame 10, a stator 20 attached to the stator frame 10, a shaft 30 fixed to the stator frame 10, and a rotor 40 arranged on the outer circumferential side of the shaft 30 relative to the stator 20.

[0018] In addition, the hoisting machine 200 of this embodiment has an external rotor type rotating electric machine 100, a drum 50 that rotates integrally with the rotor 40 around the shaft 30, a sheave 60 provided on the drum 50 for winding a rope 80 around the outside, and a brake 70 for suppressing the rotation of the drum 50.

[0019] Although not specifically shown, when installing the hoisting machine 200, the lower part of the stator frame 10 is fixed to a structural member by means of bolts or the like.

[0020] In this embodiment, unless otherwise specified, the terms "inner diameter side" and "outer diameter side" refer to the side closer to and the side farther from the center of the rotation axis of shaft 30, respectively. The term "radial direction" refers to a linear direction perpendicular to the rotation axis of shaft 30, and the term "circumferential direction" refers to the rotation direction of the rotation axis of shaft 30.

[0021] The stator 20 includes a stator core 21 and a coil 22 .

[0022] The stator core 21 is made of a processed magnetic material. For example, a core made of processed cast iron or a laminated core of a magnetic material formed into any shape by press processing or laser processing can be used as the stator core 21. Thin silicon steel sheets are generally used as the material for the magnetic material, but this is not limited to this. In this embodiment, the stator core 21 is made of a split core divided into multiple pieces in the circumferential direction, but it may also be an integrated core that is not divided.

[0023] The coil 22 is composed of an armature winding that is concentratedly wound around the stator core 21. The armature winding may be a conductor made of copper-based electrical conductor coated with an insulating coating (e.g., enamel, engineering plastic, etc.). An insulator (e.g., insulating paper, a resin bobbin, etc.) may be interposed between the coil 22 and the stator core 21.

[0024] The rotor 40 has a rotor core 41 and permanent magnets 42. The multiple permanent magnets 42 are fixed to the inner diameter side of the rotor core 41. A gap 43 is formed between the stator 20 and the rotor 40.

[0025] In this embodiment, an example will be described in which a concentrated winding outer rotor type permanent magnet synchronous motor having 36 coils and 32 permanent magnets is assumed, but the number of coils and permanent magnets is not limited to this.

[0026] A portion of the drum 50 serves as the rotor core 41. Therefore, the drum 50 is integrated with the rotor 40 and functions as a rotor frame. The centers of the drum 50 and the stator 20 are aligned, and the drum 50 rotates around the shaft 30 via bearings 31. A sheave 60 is fixed to the drum 50. A rope 80 is hung on the sheave 60, and when the drum 50 rotates, the sheave 60 rotates together, allowing the rope 80 to be fed.

[0027] As shown in Fig. 2, the brake 70 is fixed to a brake mounting surface on a shoulder portion of the stator frame 10. As shown in Fig. 1, the brake 70 has a brake gap 71 between it and the outer diameter surface of the drum 50, and can stop the rotation of the drum 50 by pressing a brake shoe against the drum 50 with the force of an internal spring. In this embodiment, the brake 70 is installed in two locations, but this is not limited thereto and it may be installed in one location, for example.

[0028] Next, the stator frame 10 of this embodiment will be described.

[0029] A stator 20 is fixed to the stator frame 10, and a stator core 21 of the stator 20 is in contact with a first portion 11 of the stator frame 10. The stator 20 can be fixed, for example, by fastening the stator core 21 to the stator frame 10 in the axial direction (Z direction) with bolts, but it may also be fixed by press-fitting or other methods.

[0030] When the hoisting machine 200 is operated, losses occur in the stator core 21, coils 22, and permanent magnets 42 due to the passage of current, and each of these components generates heat. The generated heat is conducted mainly through metal parts with good thermal conductivity, and is radiated mainly from the outer surface of the stator frame 10 of the hoisting machine 200 and the outer surface of the drum 50, or to structural members at the foot of the hoisting machine 200. If heat radiation is insufficient, the insulation of the coils 22 will break down, which will be one of the causes of a malfunction of the hoisting machine 200.

[0031] Therefore, the stator frame 10 of this embodiment has a recess 13 formed around the axis 30 and recessed in the axial direction of the axis 30 (Z direction in the figure), a first portion 11 located between the recess 13 and the stator core 21 and in contact with the stator core 21, a second portion 12 located between the recess 13 and the axis 30 and in contact with the axis 30, and a rib 15 formed within the recess 13 and connecting the first portion 11 and the second portion 12, and the rib 15 is formed integrally with the first portion 11 and the second portion 12 and is positioned so as to overlap with the stator core 21.

[0032] With the configuration of this embodiment, heat generated in the coil 22 is transferred to the stator core 21, and since the stator core 21 is in contact with the first portion 11 of the stator frame 10, the heat of the stator core 21 is easily transferred to the first portion 11 of the stator frame 10. For this reason, it is desirable that the stator core 21 be in contact with the first portion 11 over the entire surface.

[0033] The stator frame 10 has a recess 13 formed therein. The entire surface of the recess 13 serves as a heat dissipation surface to the outside air. This increases the area of ​​the heat dissipation surface and shortens the heat flow path from the first portion 11 to the heat dissipation surface. This improves heat dissipation performance and reduces the temperature of the coil 22. This effect is enhanced the deeper the recess 13 is, in other words, the larger the area where the stator core 21 and the recess 13 overlap. It is most desirable that the entire axial dimension of the stator core 21 or almost the entire axial dimension of the stator core 21 overlaps with the recess 13. However, it is desirable that at least half of the axial dimension of the stator core 21 (position A-A' in FIG. 1 ) overlaps with the recess 13. In this case, the heat flow path to the recess 13 is longer in the area where the stator core 21 and the recess 13 do not overlap. However, since there is also a path for heat to be transmitted to the shaft 30 via the portion where the recess 13 is not formed, heat can also be dissipated via this path.

[0034] Furthermore, heat transferred to the first portion 11 is transferred through the ribs 15 to the second portion 12, shaft 30, bearing 31, and drum 50, thereby further improving heat dissipation. The ribs 15 themselves act as heat dissipation fins within the recess 13, expanding the surface area and further enhancing cooling performance. Furthermore, because the ribs 15 are integrally formed with the first portion 11 and the second portion 12, no gaps are created, unlike when separate, external heat dissipation fins are attached. This increases the thermal conductivity of the stator frame 10 and improves the cooling performance of the stator 20 without increasing the number of components. Furthermore, because the ribs 15 are positioned so as to overlap with the stator core 21, the heat flow path from the stator core 21 to the ribs 15 is shortened, thereby improving thermal conductivity.

[0035] The stator frame 10 also has a bottom 14 in the axial direction of the recess 13. The bottom 14 is formed in a substantially annular shape.

[0036] It is desirable that the ribs 15 are connected to the bottom portion 14 and are formed integrally with the bottom portion 14. As a result, the ribs 15 not only function as a heat transfer path and a heat dissipation surface, but also support the structure of the bottom portion 14 as a strength member, and can suppress distortion and bending during casting. In addition, the effect of suppressing deformation caused by thermal expansion during operation of the hoisting machine 200 is also obtained. However, the present invention is not limited to this, and the ribs 15 may be configured not to be connected to the bottom portion 14.

[0037] It is desirable that the axial dimension (R2) of the rib 15 is contained within the recess 13. As a result, even if the rib 15 is added, the external size of the hoisting machine 200 does not increase, and therefore, the hoisting machine 200 can be prevented from becoming larger.

[0038] The stator frame 10 preferably has a plurality of ribs 15. In this embodiment, as shown in Fig. 2, twelve ribs 15 are provided in the circumferential direction, but this is not limited thereto, and four or more ribs are preferable. As shown in Fig. 3, the circumferential dimension (rib width) (R1) of the ribs 15 is set to a size that does not cause problems in molding during casting. Furthermore, the ribs 15 may be tapered in the height direction (Z direction) to improve ease of removal.

[0039] As shown in FIG. 3, the ribs 15 are disposed between the stator core 21 and the shaft 30, extending radially outward from the center of the shaft 30, and preferably arranged side by side in the radial direction. In this embodiment, the ribs 15 are disposed at equal intervals in the circumferential direction, but they may also be disposed at uneven intervals. Furthermore, if the ribs 15 interfere with other components of the traction machine 200 or uneven portions of a frame such as the stator frame 10, the interfering portions may be omitted. In this embodiment, the ribs 15 have a substantially rectangular parallelepiped shape, but the corners may be chamfered or rounded. The boundary between the stator frame 10 and the ribs 15 may be filleted.

[0040] Furthermore, the circumferential dimension (rib width) (R1) of the rib 15 is smaller than the axial dimension (R2) of the rib 15. In other words, the axial dimension (R2) of the rib 15 is made larger. This allows the surface area of ​​the rib 15 to be larger than when the axial dimension (R2) of the rib 15 is small, thereby improving heat dissipation performance.

[0041] According to this embodiment, it is possible to realize an outer rotor type rotating electric machine 100 and a hoisting machine 200 in which the thermal conductivity of the stator frame 10 is increased and the cooling performance of the stator 20 is improved without increasing the number of parts. [Example]

[0042] FIG. 4 is a front view of a hoisting machine employing an outer rotor type rotating electric machine according to the second embodiment.

[0043] Example 2 is a modification of Example 1, in which the dimension (R1) of the rib 15 in the circumferential direction of the axis 30 increases as it approaches the axis 30. The thermal resistance increases as it is farther from the heat source, but the cross-sectional area is increased accordingly, so that the increase in thermal resistance even at a distance from the heat source can be suppressed.

[0044] In this embodiment, the angle at which the ribs 15 spread is 10 degrees, i.e., the angle between the side surface of the rib 15 and the direction in which the rib 15 extends is 5 degrees, but this is not limiting. Adjacent ribs 15 may also contact each other around the axis 30. It is desirable that the contact boundary between the ribs 15 is smoothly formed with a fillet.

[0045] As in Example 1, it is desirable that the dimension (R1) of the narrowest circumferential dimension of the rib 15 is smaller than the dimension (R2) of the axial direction of the rib 15. There are no particular restrictions on the relationship between the dimension of the widest circumferential dimension of the rib 15 and other dimensions.

[0046] According to this embodiment, in addition to the effects of Embodiment 1, since the cross-sectional area of the rib 15 increases as it approaches the shaft 30, it is possible to suppress an increase in thermal resistance even when away from the first portion 11 of the stator frame 10, and more heat from the first portion 11 can be conducted than in Embodiment 1. Thereby, the effect of further reducing the temperature of the coil 22 is obtained.

Embodiment

[0047] FIG. 5 is a front view of a hoisting machine employing the outer-rotor type rotating electric machine of Embodiment 3. FIG. 6 is a cross-sectional view of half of the axial plane of the hoisting machine employing the outer-rotor type rotating electric machine of Embodiment 3.

[0048] Embodiment 3 is a modified example of Embodiment 1, and is an embodiment in which the dimension of the rib 15 in the axial direction (Z direction in the figure) increases as it approaches the shaft 30.

[0049] As shown in FIG. 6, the rib 15 of this embodiment forms a taper in which the height from the bottom 14 changes as it moves away from the shaft 30. At this time, when the axial dimension on the outer diameter side of the rib 15 is R3 and the axial dimension on the inner diameter side is R4, the relationship is R1 < R3 < R4.

[0050] According to this embodiment, in addition to the effects of Embodiment 1, similar to Embodiment 2, since the cross-sectional area of the rib 15 increases as it approaches the shaft 30, it is possible to suppress an increase in thermal resistance even when away from the first portion 11 of the stator frame 10, and more heat from the first portion 11 can be conducted than in Embodiment 1. Also, since the surface area of the rib 15 is larger than that in Embodiment 1, more heat can be dissipated. Thereby, the effect of further reducing the temperature of the coil 22 is obtained.

[0051] Also, by combining the shapes of the ribs 15 of Embodiment 2 and Embodiment 3, the heat conduction in the rib 15 can be further improved.

Embodiment

[0052] FIG. 7 is a front view of a hoisting machine employing the outer-rotor type rotating electric machine of Embodiment 4.

[0053] The fourth embodiment is a modification of the first embodiment, in which the stator frame 10 has rib bridges 16 that connect adjacent ribs 15 to each other.

[0054] As shown in Figure 7, this embodiment shows an example in which an annular rib bridge 16 is formed, but is not limited to this. It is desirable that the rib bridge 16 is also connected to the bottom portion 14, but is not limited to this. It is desirable that the axial dimension of the rib bridge 16 is equal to or less than the average axial dimension of the ribs 15, but is not limited to this. It is desirable that the radial dimension of the rib bridge 16 (the width of the rib bridge 16) is equal to or greater than the circumferential dimension of the rib 15 (the width of the rib 15), but is not limited to this.

[0055] According to this embodiment, in addition to the effects of embodiment 1, higher cooling performance can be obtained because the rib bridges 16 increase the heat dissipation area. Furthermore, since the ribs 15 are supported in the circumferential direction, distortion is less likely to occur during casting.

[0056] Moreover, by combining Example 4 with Example 2 and / or Example 3, the heat conduction in the rib 15 can be further improved. [Example]

[0057] FIG. 8 is a diagram illustrating a schematic configuration of an elevator according to a fifth embodiment.

[0058] The elevator 300 of this embodiment includes the hoisting machine 200 described in the first to fourth embodiments, a rope 80 wound around the sheave 60 of the hoisting machine 200, and a car 90 connected to the rope 80. The elevator 300 also includes a counterweight 95 connected to the rope 80 on the opposite side of the car 90.

[0059] In this embodiment, the hoisting machine 200 is installed at the top of the hoistway 301, but the present invention is not limited to this.

[0060] Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations described in the embodiments, and various modifications are possible within the scope of the technical concept of the present invention. In addition, some or all of the configurations described in each embodiment may be combined and applied. [Explanation of symbols]

[0061] 10: Stator frame 11:First part 12:Second part 13: Recess 14: Bottom 15: Rib 16: Rib Bridge 20: Stator 21: Stator core 22: Coil 30: Axis 31: Bearing 40: Rotor 41: Rotor core 42: Permanent magnet 43: Gap 50: Drums 60: Sheave 70: Brake 71: Brake gap 80: Rope 90: Car 95: Counterweight 100: External rotor type rotating electric motor 200: Hoisting machine 300: Elevator 301: Elevator shaft

Claims

1. a stator frame; a stator attached to the stator frame; a shaft fixed to the stator frame; an outer rotor disposed on the outer peripheral side of the shaft relative to the stator; the stator includes a stator core and a coil; the stator frame has: a recess formed around the shaft and recessed in the axial direction of the shaft; a first portion located between the recess and the stator core and in contact with the stator core; a second portion located between the recess and the shaft and in contact with the shaft; and a rib formed within the recess and connecting the first portion and the second portion; an outer rotor type rotating electric machine, characterized in that the rib is formed integrally with the first portion and the second portion and is positioned so as to overlap the stator core;

2. In claim 1, the stator frame has an axial bottom of the recess; The outer rotor type rotating electric machine is characterized in that the rib is connected to the bottom portion and is formed integrally with the bottom portion.

3. In claim 1, An outer rotor type rotating electric machine, characterized in that the stator frame has a plurality of the ribs.

4. In claim 1, An outer rotor type rotating electric machine, characterized in that a position of half of the axial dimension of the stator core overlaps with the recess.

5. In claim 1, An outer rotor type rotating electric machine, characterized in that the dimension of the narrowest part of the rib in the circumferential direction of the shaft is smaller than the dimension of the rib in the axial direction.

6. In claim 1, An outer rotor type rotating electric machine, characterized in that the dimension of the rib in the circumferential direction of the shaft increases as it approaches the shaft.

7. In claim 1, An outer rotor type rotating electric machine, characterized in that the dimension of the rib in the axial direction increases as it approaches the axis.

8. In claim 3, The stator frame has a rib bridge that connects adjacent ribs.

9. An outer rotor type rotating electric machine according to any one of claims 1 to 8; a drum that rotates integrally with the rotor around the axis; a sheave provided on the drum for winding a rope around the outside; and a brake for suppressing rotation of the drum.

10. The hoisting machine according to claim 9; The rope wound around the sheave of the hoist; An elevator comprising: a car connected to the rope.

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