Motor

Abstract

The motor (100) includes a motor housing (1) having a cylindrical frame (1a), a stator (2) arranged on the inner circumference of the frame (1a), a rotor arranged on the inner circumference of the stator (2), a fan housing attached to one axial end of the motor housing (1), and a cooling fan arranged inside the fan housing. The frame (1a) is formed with a space (1f) that penetrates the frame (1a) in the axial direction and opens radially inward. The portion of the space (1f) that opens radially inward is closed by the outer periphery (2e) of the stator (2). The space (1f) and the outer periphery (2e) of the stator (2) form an air passage (11) with a closed cross section that extends in the axial direction. A first cooling fin (1i) is provided only on the inner periphery (1g) of the frame (1a), extending radially inward toward the outer periphery (2e) of the stator (2) and positioned within the air passage (11).

Description

[Technical field]

[0001] The present disclosure relates to a motor with a cooling fan. [Background technology]

[0002] Conventionally, motors with cooling fans are known. Generally, motors with cooling fans used for industrial purposes are required to have high output and high torque. As the output and torque of motors with cooling fans increase, the amount of heat generated from the stator coil increases. Therefore, motors with cooling fans equipped with a structure for efficiently cooling the stator have been developed.

[0003] For example, Patent Document 1 discloses a motor with a cooling fan in which a space that opens radially inward is formed in the inner periphery of a frame disposed around the outer periphery of a stator, and the part of the space that opens radially inward is blocked by the outer periphery of the stator, thereby forming a ventilation passage with a closed cross section that extends in the axial direction. With the technology disclosed in Patent Document 1, the airflow generated by the cooling fan passes through the ventilation passage without diffusing into the atmosphere around the motor with a cooling fan, so that the stator can be cooled efficiently. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 1-157554 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology disclosed in Patent Document 1 has a structure in which the stator is held by the inner periphery of the frame, and in order to obtain a frictional force that prevents the stator from rotating relative to the frame when the motor with cooling fan is driven, it is necessary to ensure a sufficient contact area between the inner periphery of the frame and the outer periphery of the stator. On the other hand, with the technology disclosed in Patent Document 1, if the contact area between the inner periphery of the frame and the outer periphery of the stator is increased, the surface area of ​​the ventilation passage must be inevitably reduced, resulting in a problem of insufficient cooling of the stator.

[0006] The present disclosure has been made in consideration of the above, and has an object to provide a motor that can improve the cooling performance for the stator while ensuring frictional force that prevents the stator from rotating. [Means for solving the problem]

[0007] In order to solve the above problems and achieve the object, the motor according to the present disclosure includes a motor housing having a cylindrical frame, a stator arranged on the inner circumference of the frame, a rotor arranged on the inner circumference of the stator, a shaft connected to the rotor, a fan housing attached to one axial end of the motor housing, and a cooling fan arranged inside the fan housing. The frame is formed with a space that penetrates the frame in the axial direction and opens radially inward. The portion of the space that opens radially inward is closed by the outer periphery of the stator. The space and the outer periphery of the stator form a ventilation passage with a closed cross section that passes through the airflow generated by the cooling fan and extends in the axial direction. The frame is provided only on the inner periphery with a first cooling fin that extends radially inward toward the outer periphery of the stator and is located in the ventilation passage. The frame is formed with a first fixing hole penetrating from the outer periphery to the inner periphery of the frame at a position avoiding the ventilation passage. The stator is formed with a second fixing hole at a position avoiding the ventilation passage and communicating with the first fixing hole. Fixing members for fixing the frame and the stator are disposed in the first fixing hole and the second fixing hole. Effect of the Invention

[0008] The motor according to the present disclosure has an advantage in that it is possible to improve the cooling performance for the stator while ensuring the frictional force that prevents the stator from rotating. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a half-sectional view showing the configuration of a motor according to a first embodiment, taken along the axial direction of the motor; [Diagram 2] FIG. 1 is a cross-sectional view showing a configuration of a frame and a stator of a motor according to a first embodiment, the cross-sectional view being taken along a direction perpendicular to the axial direction of the motor. [Diagram 3] FIG. 11 is a partially enlarged cross-sectional view showing the configuration of a frame and a stator of a motor according to a second embodiment, the cross-sectional view being taken along a direction perpendicular to the axial direction of the motor. [Figure 4] FIG. 11 is a partially enlarged cross-sectional view showing a configuration of a frame and a stator of a motor according to a first modification of the second embodiment, the cross-sectional view being taken along a direction perpendicular to the axial direction of the motor. [Diagram 5] FIG. 11 is a partially enlarged cross-sectional view showing a configuration of a frame and a stator of a motor according to a second modification of the second embodiment, taken along a direction perpendicular to the axial direction of the motor; [Figure 6] FIG. 13 is a schematic diagram showing a stator according to a second embodiment and a molding location where a second cooling fin is molded; [Figure 7] FIG. 11 is a partially enlarged cross-sectional view showing the configuration of a motor according to a third embodiment, the cross-sectional view being cut along a direction perpendicular to the axial direction of the motor. [Figure 8] FIG. 13 is a partially enlarged cross-sectional view showing the configuration of a motor according to a first modification of the third embodiment, taken along a direction perpendicular to the axial direction of the motor; [Figure 9] FIG. 13 is a partially enlarged cross-sectional view showing the configuration of a motor according to a second modification of the third embodiment, taken along a direction perpendicular to the axial direction of the motor; [Figure 10] FIG. 13 is a partially enlarged cross-sectional view showing the configuration of a motor according to a fourth embodiment, the cross-sectional view being cut along a direction perpendicular to the axial direction of the motor. [Figure 11] FIG. 13 is a partially enlarged cross-sectional view showing the configuration of a motor according to a fifth embodiment, the cross-sectional view being cut along a direction perpendicular to the axial direction of the motor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A motor according to an embodiment will be described in detail below with reference to the drawings, however, the present invention is not limited to the embodiment.

[0011] Embodiment 1 FIG. 1 is a half-side cross-sectional view showing the configuration of a motor 100 according to the first embodiment, and is a cross-sectional view of the motor 100 cut along the axial direction. FIG. 2 is a cross-sectional view showing the configuration of a frame 1a and a stator 2 of the motor 100 according to the first embodiment, and is a cross-sectional view of the motor 100 cut along a direction perpendicular to the axial direction. As shown in FIG. 1, the motor 100 includes a motor housing 1, a stator 2, a rotor 3, a shaft 4, a fan housing 5, and a cooling fan 6. A stator core 2a of the stator 2, which will be described later, is formed in a cylindrical shape having a central axis C. Hereinafter, when describing the directions of each component of the motor 100, a direction parallel to the central axis C is referred to as an axial direction, a direction perpendicular to the central axis C is referred to as a radial direction, and a rotation direction around the central axis C is referred to as a circumferential direction. In this specification, the inner circumference and the outer circumference refer to the inner circumference and the outer circumference of the cylindrical stator core 2a. In addition, the left side of the paper in FIG. 1 is one side in the axial direction, and the right side of the paper in FIG. 1 is the other side in the axial direction.

[0012] The motor housing 1 is a cylindrical member that houses the stator 2, the rotor 3, and a portion of the shaft 4. The motor housing 1 has a frame 1a, a first bracket 1b, and a second bracket 1c. The first bracket 1b and the second bracket 1c are disposed apart from each other in the axial direction, sandwiching the frame 1a therebetween.

[0013] The frame 1a has a cylindrical shape with both axial ends open. As shown in Fig. 2, the frame 1a has a cylindrical shape with an outer periphery that is roughly octagonal and an inner periphery that is circular. As shown in Fig. 1, the frame 1a connects a first bracket 1b and a second bracket 1c.

[0014] The first bracket 1b is attached to one end of the frame 1a in the axial direction. The first bracket 1b closes a part of the opening at one end of the frame 1a in the axial direction. The second bracket 1c is attached to the other end of the frame 1a in the axial direction. The second bracket 1c closes a part of the opening at the other end of the frame 1a in the axial direction. The first bracket 1b and the second bracket 1c each have an insertion hole 1d into which the shaft 4 is inserted. A bearing 7 is disposed in a part of the inner peripheral surface of each insertion hole 1d. The frame 1a may have a cylindrical shape with a bottom. In this configuration, the motor housing 1 has one bracket attached to one end or the other end of the frame 1a in the axial direction.

[0015] The stator 2 is disposed on the inner periphery of the frame 1a. As shown in Fig. 2, the stator 2 is fitted and held in the inner periphery of the frame 1a. The stator 2 has a stator core 2a and a plurality of coils 2b.

[0016] The stator core 2a is, for example, a laminate of multiple electromagnetic steel sheets stacked in the axial direction. The shape of the electromagnetic steel sheets constituting the stator core 2a is annular. Each of the multiple electromagnetic steel sheets is fixed to one another by crimping, welding, adhesive, or the like. In this embodiment, the shape of the stator core 2a is cylindrical. The stator core 2a has multiple teeth 2c arranged in a row in the circumferential direction and a back yoke portion 2d that connects the multiple teeth 2c at the outer periphery of each tooth 2c.

[0017] The teeth 2c are arranged radially about the central axis C. The teeth 2c are arranged at equal angles in the circumferential direction. The back yoke portion 2d is formed in a cylindrical shape.

[0018] The coil 2b is wound around each of the teeth 2c. The coil 2b generates a magnetic field for rotating the rotor 3 and shaft 4 shown in FIG. 1 in a circumferential direction. A magnetic field is generated by supplying an AC current from an AC power supply device (not shown) to the coil 2b. This magnetic field generates a torque that rotates the rotor 3 and shaft 4 shown in FIG. 1 in the circumferential direction, and the rotor 3 and shaft 4 can be rotated in the circumferential direction. The AC power supply device is, for example, an inverter device.

[0019] As shown in FIG. 1, the rotor 3 is disposed on the inner circumference of the stator 2. The rotor 3 is disposed with a gap between it and the stator 2. The rotor 3 is rotatable about a central axis C as a rotation axis. In this embodiment, the rotor 3 has a cylindrical shape. The rotor 3 is, for example, a laminate of a plurality of electromagnetic steel plates stacked in the axial direction. The electromagnetic steel plates constituting the rotor 3 have an annular shape. Each of the plurality of electromagnetic steel plates is fixed to one another by caulking, welding, bonding, or the like. A through hole 3a extending in the axial direction is formed in the center of the rotor 3.

[0020] The shaft 4 is connected to the rotor 3. The shaft 4 is disposed in a through hole 3a of the rotor 3 and extends in the axial direction. The shaft 4 is disposed coaxially with the central axis C. The shaft 4 is rotatably supported by two bearings 7. One axial end of the shaft 4 protrudes into an accommodating recess 1e, which will be described later, through an insertion hole 1d of the first bracket 1b. The other axial end of the shaft 4 protrudes to the outside of the motor housing 1 through an insertion hole 1d of the second bracket 1c.

[0021] An accommodating recess 1e is formed at one end of the axial direction of the first bracket 1b, recessed toward the other end of the axial direction toward the frame 1a. The accommodating recess 1e opens to one end of the axial direction. A detector 8 is disposed in the accommodating recess 1e. The detector 8 is a device for detecting the circumferential angle of the shaft 4. The detector 8 has a scale 8a having a plurality of magnetic poles or scribed lines, and a sensor 8b for detecting the rotation angle of the shaft 4 from the scale 8a. The scale 8a is attached to a portion of the shaft 4 that protrudes from the insertion hole 1d of the first bracket 1b. The sensor 8b is attached to the bottom surface of the accommodating recess 1e. The opening of the accommodating recess 1e is closed by a detector cover 9. The detector cover 9 covers the detector 8 from one end of the axial direction.

[0022] The fan housing 5 is attached to one axial end of the motor housing 1. More specifically, the fan housing 5 is attached to one axial end of the first bracket 1b. The fan housing 5 is shaped like a box with an open surface facing the motor housing 1. The fan housing 5 has a peripheral wall 5a and an axial end wall 5b. The peripheral wall 5a is a cylindrical portion extending in the circumferential direction. One axial end of the peripheral wall 5a is closed by the axial end wall 5b. A plurality of exhaust ports 11e are formed in the axial end wall 5b to exhaust the air flow that has flowed into the ventilation passage 11 described below. The other axial end of the peripheral wall 5a is open.

[0023] The cooling fan 6 is disposed inside the fan housing 5. The cooling fan 6 generates an air flow that passes through the ventilation passage 11. The white arrow Y in Fig. 1 indicates the flow of the air flow. Hereinafter, the direction in which the air flow flows is referred to as the airflow direction. The air flow flows from the other side to one side in the axial direction.

[0024] Next, the configuration of ventilation passage 11 and the configuration around ventilation passage 11 will be described in detail.

[0025] As shown in FIG. 2, the frame 1a is formed with a space 1f that penetrates the frame 1a in the axial direction and opens radially inward. The portion of the space 1f that opens radially inward is closed by the outer periphery 2e of the stator 2. The space 1f and the outer periphery 2e of the stator 2 form a first ventilation passage 11a. The positions of the first ventilation passages 11a are at the four corners of the frame 1a in this embodiment, but may be changed as appropriate. The number of the first ventilation passages 11a is four in this embodiment, but may be changed as appropriate. The positions and number of the space 1f are also changed as appropriate by changing the positions and number of the first ventilation passages 11a. As shown in FIG. 1, the first ventilation passage 11a is a closed cross section that passes through the airflow generated by the cooling fan 6 and extends in the axial direction. An inlet 11d is formed at the other axial end of the frame 1a to allow airflow to flow from the outside of the motor 100 into the first ventilation passage 11a.

[0026] The first bracket 1b is formed with a second ventilation passage 11b communicating with the first ventilation passage 11a. The second ventilation passage 11b is connected to a downstream end (one end in the axial direction) of the first ventilation passage 11a in the airflow direction. The second ventilation passage 11b is provided radially outward of the bearing 7 and the accommodating recess 1e.

[0027] A third ventilation passage 11c communicating with the second ventilation passage 11b is formed in the fan housing 5. The third ventilation passage 11c is connected to the downstream end in the airflow direction of the second ventilation passage 11b (one end in the axial direction). A bell mouth 10 that gradually reduces in diameter toward the downstream side in the airflow direction (one end in the axial direction) is provided inside the fan housing 5. The downstream end of the bell mouth 10 in the airflow direction is connected to the cooling fan 6. The bell mouth 10 is part of a wall that surrounds the third ventilation passage 11c.

[0028] In this embodiment, the first ventilation passage 11a, the second ventilation passage 11b, and the third ventilation passage 11c form the ventilation passage 11. That is, the first ventilation passage 11a, the second ventilation passage 11b, and the third ventilation passage 11c are each a part of the ventilation passage 11. When the cooling fan 6 is driven, an air flow is generated that flows into the ventilation passage 11 from the inlet 11d and is discharged from the exhaust port 11e. Specifically, the air flow passes through the inlet 11d, the first ventilation passage 11a, the second ventilation passage 11b, the third ventilation passage 11c, and the cooling fan 6 in this order, and is discharged from the exhaust port 11e to the outside of the motor 100. The heat generated in the coil 2b of the stator 2 is dissipated to the outside of the motor 100 through the air flow flowing through the ventilation passage 11.

[0029] As shown in FIG. 2, a plurality of first cooling fins 1i are provided only on the inner peripheral portion 1g of the frame 1a. The first cooling fins 1i extend radially inward toward the outer peripheral portion 2e of the stator 2. The first cooling fins 1i are located in the first ventilation passage 11a. The first cooling fins 1i are provided in a portion of the inner peripheral portion 1g of the frame 1a facing the first ventilation passage 11a. A gap is provided between the tip of the first cooling fin 1i and the outer peripheral portion 2e of the stator 2. That is, the tip of the first cooling fin 1i does not contact the outer peripheral portion 2e of the stator 2. The shape of the first cooling fin 1i when viewed along the axial direction is generally rectangular in this embodiment, but may be changed as appropriate.

[0030] Next, the effects of the motor 100 according to this embodiment will be described.

[0031] In this embodiment, as shown in FIG. 2, the frame 1a is formed with a space 1f that penetrates the frame 1a in the axial direction and opens radially inward. In this embodiment, the portion of the space 1f that opens radially inward is closed by the outer periphery 2e of the stator 2. In this embodiment, as shown in FIG. 1, the space 1f and the outer periphery 2e of the stator 2 form a first ventilation passage 11a that is a closed cross section through which the airflow generated by the cooling fan 6 passes and that extends in the axial direction. In this embodiment, as shown in FIG. 2, the frame 1a is provided only on the inner periphery 1g with a first cooling fin 1i that extends radially inward toward the outer periphery 2e of the stator 2 and is located in the first ventilation passage 11a. With these configurations, the first cooling fin 1i becomes part of the surface of the first ventilation passage 11a, and the surface area of ​​the first cooling fin 1i is also included in the surface area of ​​the first ventilation passage 11a. Therefore, even if the contact area between the inner periphery 1g of the frame 1a and the outer periphery 2e of the stator 2 is sufficiently secured so that the stator 2 does not rotate, the surface area of ​​the first ventilation passage 11a can be increased. This promotes heat exchange between the air flow and the surface of the first ventilation passage 11a, and improves the cooling performance for the stator 2. Therefore, in this embodiment, the cooling performance for the stator 2 can be improved while securing the frictional force that prevents the stator 2 from rotating.

[0032] Conventionally, a technique is known in which an outer periphery of a frame is covered with a covering member such as an air guide cover to form an air passage between the outer periphery of the frame and the covering member. In the conventional technique, the covering member is necessary, and therefore the number of parts and the number of assembly steps increase, resulting in an increase in manufacturing costs. In this regard, in the present embodiment, as shown in FIG. 2, the first air passage 11a is formed by the space 1f formed in the frame 1a and the outer periphery 2e of the stator 2, so that a covering member such as an air guide cover is not required. As a result, compared to the case where an air passage is formed using a covering member such as an air guide cover, the number of parts and the number of assembly steps can be reduced, and manufacturing costs can be reduced.

[0033] The material of the frame 1a and the first cooling fin 1i shown in FIG. 2 is preferably aluminum or the like having a high thermal conductivity. In this way, the frame 1a and the first cooling fin 1i can be integrally formed by extrusion molding or pultrusion molding. In this embodiment, a space 1f opening radially inward is formed in the frame 1a, and the part of the space 1f opening radially inward is blocked by the outer periphery 2e of the stator 2, thereby forming the first ventilation passage 11a having a closed cross section. That is, the space 1f having an open cross section is formed in the frame 1a itself. Therefore, compared to the case where a ventilation passage having a closed cross section is formed in the frame 1a itself, the pressure applied to the frame 1a and the mold during extrusion molding or pultrusion molding can be reduced. This reduces molding defects of the frame 1a and extends the life of the mold, thereby reducing manufacturing costs.

[0034] In this embodiment, as shown in Fig. 2, a space 1f that opens radially inward is formed in the frame 1a, so that the outer periphery 2e of the stator 2 fits only partially into the inner periphery 1g of the frame 1a. Therefore, the compressive stress generated in the stator 2 is smaller than when the outer periphery 2e of the stator 2 fits entirely around the inner periphery 1g of the frame 1a, and the iron loss of the stator 2 can be suppressed. This reduces the amount of heat generated from the stator 2, and the temperature rise of the motor 100 can be suppressed.

[0035] Next, a modification of the first embodiment will be described.

[0036] 2, in this embodiment, the tip of the first cooling fin 1i is not in contact with the outer periphery 2e of the stator 2, but the tip of the first cooling fin 1i may be in contact with the outer periphery 2e of the stator 2. In this way, heat exchange between the first cooling fin 1i and the stator 2 is promoted, and the cooling performance for the stator 2 can be further improved.

[0037] As shown in Fig. 2, as long as the first ventilation passage 11a with a closed cross section extending in the axial direction is formed by the space 1f of the inner peripheral portion 1g of the frame 1a and the outer peripheral portion 2e of the stator 2, the structure of each component of the motor 100 is not limited to the illustrated example. For example, the shapes of the stator 2, the frame 1a, the first ventilation passage 11a, and the first cooling fins 1i may be changed as appropriate without being limited to the illustrated example. Also, for example, the number and positions of the first ventilation passage 11a and the first cooling fins 1i may be changed as appropriate without being limited to the illustrated example.

[0038] Embodiment 2 Next, a motor 100A according to a second embodiment will be described with reference to Fig. 3. Fig. 3 is a partially enlarged cross-sectional view showing the configuration of a frame 1a and a stator 2 of the motor 100A according to the second embodiment, taken along a direction perpendicular to the axial direction of the motor 100A. This embodiment differs from the first embodiment in that the motor 100A includes a second cooling fin 2f. In the second embodiment, parts that overlap with those in the first embodiment are denoted by the same reference numerals and will not be described.

[0039] A plurality of second cooling fins 2f are provided on the outer periphery 2e of the stator 2. The second cooling fins 2f extend radially outward toward the inner periphery 1g of the frame 1a. The second cooling fins 2f are located in the first ventilation passage 11a. The second cooling fins 2f are provided in a portion of the outer periphery 2e of the stator 2 facing the first ventilation passage 11a. The first cooling fin 1i and the second cooling fin 2f are in the same position in the circumferential direction, but may be in a position shifted in the circumferential direction. A gap is provided between the tip of the first cooling fin 1i and the tip of the second cooling fin 2f. That is, the tip of the first cooling fin 1i and the tip of the second cooling fin 2f are not in contact with each other. The shape of the second cooling fin 2f when viewed along the axial direction is rectangular in this embodiment, but may be changed as appropriate.

[0040] The second cooling fins 2f are provided on each of the multiple electromagnetic steel sheets constituting the stator core 2a. In the illustrated example, the second cooling fins 2f provided on each of the multiple electromagnetic steel sheets are located at the same position in the circumferential direction. That is, the second cooling fins 2f provided on each of the multiple electromagnetic steel sheets are located at overlapping positions when viewed along the axial direction, and the second cooling fins 2f at the back side of the paper surface are not visible in FIG. 3. When a ring-shaped electromagnetic steel sheet is punched out from a rectangular electromagnetic steel sheet by a press, the ring-shaped electromagnetic steel sheet and the second cooling fins 2f can be formed integrally.

[0041] In this embodiment, the outer periphery 2e of the stator 2 is provided with a second cooling fin 2f that extends radially outward toward the inner periphery 1g of the frame 1a and is located within the first ventilation passage 11a. With this configuration, the second cooling fin 2f becomes part of the surface of the first ventilation passage 11a, and the surface area of ​​the second cooling fin 2f is also included in the surface area of ​​the first ventilation passage 11a, so that the surface area of ​​the first ventilation passage 11a can be increased. This further promotes heat exchange between the air flow and the surface of the first ventilation passage 11a, and the cooling performance for the stator 2 can be further improved.

[0042] Next, a modification of the second embodiment will be described.

[0043] In this embodiment, the tip of the first cooling fin 1i and the tip of the second cooling fin 2f are not in contact with each other, but the tip of the first cooling fin 1i and the tip of the second cooling fin 2f may be in contact with each other. Also, the tip of the first cooling fin 1i is not in contact with the outer peripheral portion 2e of the stator 2 other than the second cooling fin 2f, but may be in contact with the outer peripheral portion 2e of the stator 2 other than the second cooling fin 2f. Also, in this embodiment, the tip of the second cooling fin 2f is not in contact with the inner peripheral portion 1g of the frame 1a other than the first cooling fin 1i, but may be in contact with the inner peripheral portion 1g of the frame 1a other than the first cooling fin 1i. With these configurations, the heat exchange between the frame 1a and the stator 2 is further promoted, and the cooling performance for the stator 2 can be further improved.

[0044] The second cooling fin 2f may have a configuration as shown in FIG. 4. FIG. 4 is a partially enlarged cross-sectional view showing the configuration of the frame 1a and the stator 2 of the motor 100B according to the first modified example of the second embodiment, and is a cross-sectional view of the motor 100B cut along a direction perpendicular to the axial direction. Fastening holes 2g for passing the bolts 12 are formed in some of the multiple second cooling fins 2f. The fastening holes 2g penetrate the second cooling fin 2f in the axial direction. The fastening holes 2g are circular in shape. The shape of the second cooling fin 2f in which the fastening holes 2g are formed is approximately semicircular in this modified example, but may be changed as appropriate.

[0045] The second cooling fins 2f with fastening holes 2g are provided on each of the electromagnetic steel plates constituting the stator core 2a. The second cooling fins 2f provided on each of the electromagnetic steel plates are located in overlapping positions when viewed along the axial direction, and the second cooling fins 2f at the back of the paper surface are not visible in FIG. 4. The multiple electromagnetic steel plates can be fixed to each other by passing a bolt 12 through the fastening holes 2g of each of the multiple electromagnetic steel plates constituting the stator core 2a. When a ring-shaped electromagnetic steel plate is punched out from a rectangular electromagnetic steel plate by pressing, the ring-shaped electromagnetic steel plate, the second cooling fins 2f, and the fastening holes 2g can be formed integrally. Note that the fastening holes 2g may be formed in all of the multiple second cooling fins 2f.

[0046] In this modification, the second cooling fin 2f is formed with a fastening hole 2g for passing the bolt 12. In addition, in this modification, the second cooling fin 2f with the fastening hole 2g formed therein is provided on each of the plurality of electromagnetic steel plates constituting the stator core 2a. In addition, in this modification, each of the plurality of electromagnetic steel plates constituting the stator core 2a is fixed to each other by the bolt 12 passed through the fastening hole 2g. With these configurations, the axial rigidity of the stator 2 can be improved. Note that each of the plurality of electromagnetic steel plates may be fixed by other means without passing the bolt 12 through the fastening hole 2g. In this way, the fastening hole 2g can be used as a part of the ventilation passage 11, so that the surface area of ​​the ventilation passage 11 can be increased. This further promotes heat exchange between the air flow and the surface of the ventilation passage 11, and further improves the cooling performance for the stator 2.

[0047] The second cooling fin 2f may be configured as shown in FIG. 5. FIG. 5 is a partially enlarged cross-sectional view showing the configuration of the frame 1a and the stator 2 of the motor 100C according to the second modified example of the second embodiment, and is a cross-sectional view of the motor 100C cut along a direction perpendicular to the axial direction. In FIG. 5, the second cooling fin 2f on the back side of the paper is represented by a broken line. The second cooling fin 2f provided on a part of the plurality of electromagnetic steel sheets and the second cooling fin 2f provided on the remaining part of the plurality of electromagnetic steel sheets are in positions that do not overlap when viewed along the axial direction, and the second cooling fin 2f on the back side of the paper is visible in FIG. 5. Hereinafter, the second cooling fin 2f provided on a part of the plurality of electromagnetic steel sheets may be referred to as the second cooling fin 2f on the front side, and the second cooling fin 2f provided on the remaining part of the plurality of electromagnetic steel sheets may be referred to as the second cooling fin 2f on the back side.

[0048] The front second cooling fin 2f and the rear second cooling fin 2f are positioned at different positions in the circumferential direction. The front second cooling fin 2f and the rear second cooling fin 2f are arranged in a staggered pattern. When stacking a plurality of electromagnetic steel sheets, the electromagnetic steel sheets are stacked with a phase difference of a certain angle, so that the stator 2 shown in FIG. 5 can be manufactured. In this modification, the surface area of ​​the first ventilation passage 11a can be increased compared to the case where the second cooling fins 2f provided on each of the plurality of electromagnetic steel sheets are positioned to overlap when viewed along the axial direction. This further promotes heat exchange between the air flow and the surface of the first ventilation passage 11a, and the cooling performance for the stator 2 can be further improved.

[0049] Here, the forming portion 13 where the second cooling fin 2f shown in FIG. 3 to FIG. 5 is formed in the electromagnetic steel sheet will be described. FIG. 6 is a schematic diagram showing the stator 2 according to the second embodiment and the forming portion 13 where the second cooling fin 2f is formed. FIG. 6 is a diagram showing the stator 2 and the forming portion 13 where the second cooling fin 2f is formed, viewed along the axial direction. Note that in FIG. 6, the diagonal hatching of the stator 2 is omitted for convenience of explanation. The dot-hatched portion in FIG. 6 is the forming portion 13 where the second cooling fin 2f shown in FIG. 3 to FIG. 5 is formed and is also a portion that becomes a scrap material when a ring-shaped electromagnetic steel sheet is punched out by pressing from a rectangular electromagnetic steel sheet. The shape of the outer circumferential portion 2e of the stator 2 is circular.

[0050] The second cooling fins 2f are provided only at the four corners of an imaginary square 14 circumscribing the outer periphery 2e of the stator 2. The imaginary square 14 coincides with the outer shape of the magnetic steel sheet before it is pressed to be cut into an annular shape. In the illustrated example, the second cooling fins 2f are produced using scrap material that is used when a rectangular magnetic steel sheet is pressed to be cut into an annular shape. This makes it possible to increase the surface area of ​​the first ventilation passage 11a shown in FIGS. 3 to 5 while suppressing material costs, thereby further improving the cooling performance for the stator 2.

[0051] As shown in Figures 3 to 5, as long as the first ventilation passage 11a with a closed cross section extending in the axial direction is formed by the space 1f of the inner peripheral portion 1g of the frame 1a and the outer peripheral portion 2e of the stator 2, the structure of each component of the motors 100A, 100B, and 100C is not limited to the illustrated example. For example, the shapes of the stator 2, the frame 1a, the first ventilation passage 11a, the first cooling fin 1i, the second cooling fin 2f, and the fastening holes 2g may be changed as appropriate without being limited to the illustrated example. Also, for example, the numbers and positions of the first ventilation passage 11a, the first cooling fin 1i, the second cooling fin 2f, and the fastening holes 2g may be changed as appropriate without being limited to the illustrated example.

[0052] Embodiment 3 Next, a motor 100D according to a third embodiment will be described with reference to Fig. 7. Fig. 7 is a partially enlarged cross-sectional view showing the configuration of a motor 100D according to the third embodiment, taken along a direction perpendicular to the axial direction of the motor 100D. This embodiment differs from the first and second embodiments in that the motor 100D includes a protruding portion 15. In the third embodiment, parts that overlap with those in the first and second embodiments will be denoted by the same reference numerals and will not be described.

[0053] The second cooling fin 2f is provided with a protruding portion 15 that protrudes in the circumferential direction. In this embodiment, the protruding portion 15 protrudes from the tip of the second cooling fin 2f toward one side in the circumferential direction. The shape of the second cooling fin 2f when viewed along the axial direction is L-shaped.

[0054] In this embodiment, the second cooling fin 2f is provided with a protruding portion 15 that protrudes in the circumferential direction. With this configuration, the protruding portion 15 becomes part of the surface of the first ventilation passage 11a, and the surface area of ​​the protruding portion 15 is also included in the surface area of ​​the first ventilation passage 11a, so that the surface area of ​​the first ventilation passage 11a can be increased. This further promotes heat exchange between the air flow and the surface of the first ventilation passage 11a, and the cooling performance for the stator 2 can be further improved.

[0055] Next, a modification of the third embodiment will be described.

[0056] In this embodiment, the tip of the first cooling fin 1i and the tip of the second cooling fin 2f are not in contact with each other, but the tip of the first cooling fin 1i and the tip of the second cooling fin 2f may be in contact with each other. Also, the tip of the first cooling fin 1i is not in contact with the outer peripheral portion 2e of the stator 2 other than the second cooling fin 2f, but may be in contact with the outer peripheral portion 2e of the stator 2 other than the second cooling fin 2f. Also, in this embodiment, the tip of the second cooling fin 2f is not in contact with the inner peripheral portion 1g of the frame 1a other than the first cooling fin 1i, but may be in contact with the inner peripheral portion 1g of the frame 1a other than the first cooling fin 1i. With these configurations, the heat exchange between the frame 1a and the stator 2 is further promoted, and the cooling performance for the stator 2 can be further improved.

[0057] The protruding portion 15 may be configured as shown in FIG. 8. FIG. 8 is a partially enlarged cross-sectional view showing the configuration of the motor 100E according to the first modification of the third embodiment, and is a cross-sectional view of the motor 100E cut along a direction perpendicular to the axial direction. Both the first cooling fin 1i and the second cooling fin 2f are provided with protruding portions 15 protruding in the circumferential direction. In this modification, the protruding portion 15 of the first cooling fin 1i protrudes from the tip of the first cooling fin 1i toward one side and the other side in the circumferential direction. The shape of the first cooling fin 1i when viewed along the axial direction is T-shaped. In this modification, the protruding portion 15 of the second cooling fin 2f protrudes from the tip of the second cooling fin 2f toward one side and the other side in the circumferential direction. The shape of the second cooling fin 2f when viewed along the axial direction is T-shaped. This modification can also achieve the same effects as those of the second embodiment.

[0058] The protruding portion 15 may be configured as shown in FIG. 9. FIG. 9 is a partially enlarged cross-sectional view showing the configuration of a motor 100F according to a second modified example of the third embodiment, in which the motor 100F is cut along a direction perpendicular to the axial direction. Both the first cooling fin 1i and the second cooling fin 2f are provided with protruding portions 15 protruding in the circumferential direction. The configuration of the protruding portion 15 of the first cooling fin 1i is the same as that of the first modified example. In this modified example, the protruding portion 15 of the second cooling fin 2f protrudes from the tip and the middle part in the extension direction of the second cooling fin 2f toward one side and the other side in the circumferential direction. This modified example can also achieve the same effects as those of the second embodiment.

[0059] As shown in Figs. 7 to 9, as long as the first ventilation passage 11a with a closed cross section extending in the axial direction is formed by the space 1f of the inner peripheral portion 1g of the frame 1a and the outer peripheral portion 2e of the stator 2, the structure of each component of the motors 100D, 100E, and 100F is not limited to the illustrated example. For example, the first cooling fin 1i and / or the second cooling fin 2f may be provided with a protrusion 15 protruding in the circumferential direction. Also, for example, the shapes of the stator 2, the frame 1a, the first ventilation passage 11a, the first cooling fin 1i, the second cooling fin 2f, and the protrusion 15 may be appropriately changed without being limited to the illustrated example. Also, for example, the number and positions of the first ventilation passage 11a, the first cooling fin 1i, the second cooling fin 2f, and the protrusion 15 may be appropriately changed without being limited to the illustrated example.

[0060] Embodiment 4 Next, a motor 100G according to a fourth embodiment will be described with reference to Fig. 10. Fig. 10 is a partially enlarged cross-sectional view showing the configuration of a motor 100G according to the fourth embodiment, taken along a direction perpendicular to the axial direction of the motor 100G. This embodiment differs from the first and second embodiments in that the motor 100G includes a groove 16. In the fourth embodiment, parts that overlap with those in the first and second embodiments are given the same reference numerals and will not be described.

[0061] A groove 16 extending in the axial direction is formed in both a portion of the inner peripheral portion 1g of the frame 1a facing the first ventilation passage 11a and a portion of the outer peripheral portion 2e of the stator 2 facing the first ventilation passage 11a. Hereinafter, when the groove 16 of the inner peripheral portion 1g of the frame 1a and the groove 16 of the outer peripheral portion 2e of the stator 2 are to be distinguished from each other, the former will be referred to as the first groove 16a and the latter will be referred to as the second groove 16b. The first groove 16a is formed in the inner peripheral portion 1g of the frame 1a in a portion other than the first cooling fin 1i and the first cooling fin 1i. The number of the first groove 16a is plural in this embodiment, but may be singular. The second groove 16b is formed in the outer peripheral portion 2e of the stator 2 in a portion other than the second cooling fin 2f and the second cooling fin 2f. The number of the second groove 16b is plural in this embodiment, but may be singular. When producing the frame 1a by extrusion or pultrusion, the frame 1a and the first groove 16a can be formed integrally. Meanwhile, when an annular electromagnetic steel sheet is pressed out from a rectangular electromagnetic steel sheet, the annular electromagnetic steel sheet constituting the stator 2 and the second groove 16b can be formed integrally.

[0062] In this embodiment, grooves 16 extending in the axial direction are formed in both the portion of the inner periphery 1g of the frame 1a facing the first ventilation passage 11a and the portion of the outer periphery 2e of the stator 2 facing the first ventilation passage 11a. With this configuration, the groove walls of the grooves 16 become part of the surface of the first ventilation passage 11a, and the surface area of ​​the groove walls of the grooves 16 is also included in the surface area of ​​the first ventilation passage 11a, so that the surface area of ​​the first ventilation passage 11a can be increased. This further promotes heat exchange between the air flow and the surface of the first ventilation passage 11a, and the cooling performance for the stator 2 can be further improved.

[0063] Next, a modification of the fourth embodiment will be described.

[0064] In this embodiment, the tip of the first cooling fin 1i and the tip of the second cooling fin 2f are not in contact with each other, but the tip of the first cooling fin 1i and the tip of the second cooling fin 2f may be in contact with each other. Also, the tip of the first cooling fin 1i is not in contact with the outer peripheral portion 2e of the stator 2 other than the second cooling fin 2f, but may be in contact with the outer peripheral portion 2e of the stator 2 other than the second cooling fin 2f. Also, in this embodiment, the tip of the second cooling fin 2f is not in contact with the inner peripheral portion 1g of the frame 1a other than the first cooling fin 1i, but may be in contact with the inner peripheral portion 1g of the frame 1a other than the first cooling fin 1i. With these configurations, the heat exchange between the frame 1a and the stator 2 is further promoted, and the cooling performance for the stator 2 can be further improved.

[0065] As shown in FIG. 10, as long as the first ventilation passage 11a with a closed cross section extending in the axial direction is formed by the space 1f of the inner peripheral portion 1g of the frame 1a and the outer peripheral portion 2e of the stator 2, the structure of each component of the motor 100G is not limited to the illustrated example. For example, a groove 16 extending in the axial direction may be formed in either or both of a portion of the inner peripheral portion 1g of the frame 1a facing the first ventilation passage 11a and a portion of the outer peripheral portion 2e of the stator 2 facing the first ventilation passage 11a. Also, for example, the shapes of the stator 2, the frame 1a, the first ventilation passage 11a, the first cooling fin 1i, the second cooling fin 2f, and the groove 16 may be appropriately changed without being limited to the illustrated example. Also, for example, the number and positions of the first ventilation passage 11a, the first cooling fin 1i, the second cooling fin 2f, and the groove 16 may be appropriately changed without being limited to the illustrated example.

[0066] Embodiment 5. Next, a motor 100H according to a fifth embodiment will be described with reference to Fig. 11. Fig. 11 is a partially enlarged cross-sectional view showing the configuration of a motor 100H according to the fifth embodiment, taken along a direction perpendicular to the axial direction of the motor 100H. This embodiment differs from the first embodiment in that the motor 100H includes a fixed member 17. In the fifth embodiment, parts that overlap with those in the first embodiment will be denoted by the same reference numerals and will not be described.

[0067] A first fixing hole 1j is formed in the frame 1a. The first fixing hole 1j is formed at a position avoiding the first ventilation passage 11a, and penetrates from the outer peripheral portion 1h to the inner peripheral portion 1g of the frame 1a. A second fixing hole 2h is formed in the stator 2. The second fixing hole 2h is formed at a position avoiding the first ventilation passage 11a and at a position communicating with the first fixing hole 1j. The second fixing hole 2h is disposed radially inward from the first fixing hole 1j. The second fixing hole 2h opens to the outer peripheral portion 2e of the stator 2. The radially inner opening of the first fixing hole 1j and the radially outer opening of the second fixing hole 2h communicate with each other. A fixing member 17 for fixing the frame 1a and the stator 2 is disposed in the first fixing hole 1j and the second fixing hole 2h. The fixing member 17 is, for example, a pin.

[0068] In this embodiment, the frame 1a is formed with a first fixing hole 1j that penetrates from the outer peripheral portion 1h to the inner peripheral portion 1g of the frame 1a at a position that avoids the first ventilation passage 11a. In addition, in this embodiment, the stator 2 is formed with a second fixing hole 2h at a position that avoids the first ventilation passage 11a and that communicates with the first fixing hole 1j. In addition, in this embodiment, fixing members 17 that fix the frame 1a and the stator 2 are arranged in the first fixing hole 1j and the second fixing hole 2h. With this configuration, the fixing members 17 arranged in the first fixing hole 1j and the second fixing hole 2h can prevent the stator 2 from rotating and moving in the axial direction, so that the stator 2 can be prevented from rotating and from falling off at the same time. In addition, when a fixing member 17 is placed in the first fixing hole 1j and the second fixing hole 2h, if a gap 18 occurs in a portion of the first fixing hole 1j radially outward from the fixing member 17 as shown in the figure, the gap 18 may be sealed using a sealing material 19.

[0069] Next, a modification of the fifth embodiment will be described.

[0070] In this embodiment, as shown in Fig. 11, as long as a first ventilation passage 11a with a closed cross section extending in the axial direction is formed by a space 1f of an inner peripheral portion 1g of the frame 1a and an outer peripheral portion 2e of the stator 2, the structure of each component of the motor 100H is not limited to the illustrated example. For example, the shapes of the stator 2, the frame 1a, the first ventilation passage 11a, the first cooling fin 1i, the first fixing hole 1j, the second fixing hole 2h, the fixing member 17, and the sealing member 19 may be changed as appropriate without being limited to the illustrated example. Also, for example, the numbers and positions of the first fixing hole 1j, the second fixing hole 2h, the fixing member 17, and the sealing member 19 may be changed as appropriate without being limited to the illustrated example.

[0071] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0072] 1 motor housing, 1a frame, 1b first bracket, 1c second bracket, 1d insertion hole, 1e accommodating recess, 1f space, 1g inner periphery, 1h, 2e outer periphery, 1i first cooling fin, 1j first fixing hole, 2 stator, 2a stator core, 2b coil, 2c teeth, 2d back yoke portion, 2f second cooling fin, 2g fastening hole, 2h second fixing hole, 3 rotor, 3a through hole, 4 shaft, 5 fan housing, 5a peripheral wall portion, 5b shaft end wall, 6 cooling fan, 7 bearing, 8 detector, 8a scale, 8b sensor, 9 detector cover, 10 bell mouth, 11 ventilation passage, 11a first ventilation passage, 11b second ventilation passage, 11c third ventilation passage, 11d inlet, 11e Exhaust port, 12 bolt, 13 molding portion, 14 imaginary rectangle, 15 protrusion, 16 groove, 16a first groove, 16b second groove, 17 fixing member, 18 gap, 19 sealing material, 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H motor, C central shaft.

Claims

1. a motor housing having a cylindrical frame; a stator disposed on an inner periphery of the frame; a rotor disposed on an inner periphery of the stator; a shaft coupled to the rotor; a fan housing attached to one axial end of the motor housing; a cooling fan disposed inside the fan housing; Equipped with The frame has a space formed therein that penetrates the frame in the axial direction and opens radially inward, a portion of the space that opens radially inward is closed by an outer circumferential portion of the stator, the space and the outer periphery of the stator form an air passage with a closed cross section that extends in the axial direction and through which an airflow generated by the cooling fan passes; a first cooling fin extending radially inward toward an outer periphery of the stator and positioned within the ventilation passage is provided only on an inner periphery of the frame; a first fixing hole penetrating from an outer periphery to an inner periphery of the frame is formed in the frame at a position avoiding the ventilation passage; a second fixing hole is formed in the stator at a position away from the ventilation passage and communicating with the first fixing hole; A motor, characterized in that fixing members for fixing the frame and the stator are disposed in the first fixing hole and the second fixing hole.

2. 2. The motor according to claim 1, wherein a second cooling fin is provided on the outer periphery of the stator, extending radially outward toward the inner periphery of the frame and positioned within the ventilation passage.

3. The outer periphery of the stator has a circular shape, 3. The motor according to claim 2, wherein the second cooling fins are provided only at four corners of an imaginary square that circumscribes the outer periphery of the stator.

4. 4. The motor according to claim 2, wherein at least one of the first cooling fin and the second cooling fin is provided with a protruding portion that protrudes in a circumferential direction.

5. 2. The motor according to claim 1, wherein a groove extending in the axial direction is formed in at least one of a portion of the inner periphery of the frame facing the ventilation passage and a portion of the outer periphery of the stator facing the ventilation passage.

6. A motor as described in claim 2, characterized in that at least one of the following is satisfied: the first cooling fin and the second cooling fin are in contact with each other; the first cooling fin and a portion of the outer periphery of the stator other than the second cooling fin are in contact with each other; and the second cooling fin and a portion of the inner periphery of the frame other than the first cooling fin are in contact with each other.

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