Fully enclosed external fan motor

Abstract

To provide a quiet totally-enclosed fan-cooled motor.SOLUTION: In the totally-enclosed fan-cooled motor, a stator and a rotor are enclosed in a fully closed frame, and is configured so that: an outer fan 52 fixed to a rotating shaft of the rotor intakes outside air into the fully enclosed frame at the outside air side of a main plate of an external fan; and the air discharged from the external fan is caused to flow via multiple second ducts 92 formed on the outer periphery of the fully enclosed frame through an arcuate first duct formed at the axial end of the fully enclosed frame, and discharged to the outside. Multiple guides 911-916 are provided to intake the air flowing in the circumferential direction into the first duct so that the air discharged from the outer fan and flowing in the circumferential direction to flow into the arc-shaped first duct in a distributed manner in the circumferential direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a totally enclosed external fan motor, and particularly to a totally enclosed external fan motor for vehicles suitable for main motors for railways and the like.

Background Art

[0002] A main motor for railways (hereinafter referred to as a main motor) is a form of rotating electrical machine, and is operated with a large output while being housed in a limited space inside a bogie of a railway vehicle. Therefore, it is necessary to efficiently dissipate and cool the heat generated during operation. As main motors, there are an open-type main motor that directly introduces and passes outside air into the machine for cooling, and a totally enclosed main motor that cools while substantially isolating the inside of the machine from the outside air. In a totally enclosed main motor, the gaps between the centrifugal fans provided at both ends of the rotating shaft (shaft) inside the machine and the casing composed of a frame and brackets are minimized, and the inside is substantially isolated from the outside air. For this reason, the amount of dust taken in is small, and the leakage noise is small. The heat generated inside moves to the outside in the thickness direction of the centrifugal fan and the casing, and is finally dissipated to the outside air. Since the totally enclosed main motor can reduce the amount of dust taken in and the frequency of disassembly and cleaning, and can also reduce the leakage noise to the surroundings as a consideration for the railway line, its application to main motors for railways has been progressing in recent years.

[0003] The totally enclosed main motor includes a totally enclosed external fan main motor with fan blades (vanes) provided outside the machine on the main board, and a totally enclosed internal fan main motor with fan blades provided inside the machine on the main board. The totally enclosed external fan main motor dissipates the heat transmitted to the fan and the casing to the outside by the wind of the external fan. The totally enclosed internal fan main motor dissipates the heat transmitted to the casing through the fins provided on the casing. Generally, the totally enclosed external fan main motor can be smaller and lighter in body than the totally enclosed internal fan main motor, and has high heat dissipation. On the other hand, the totally enclosed internal fan main motor has high sound insulation and can reduce the noise to the surroundings.

[0004] When the rotation of the main motor causes pressure fluctuations in the sound field, aerodynamic noise is generated. Railway vehicles are becoming faster, and the operating rotational speed of the main motor that drives railway vehicles tends to increase. Since aerodynamic noise is proportional to the sixth power of speed, the need to suppress aerodynamic noise is increasing.

[0005] Patent Document 1 proposes a fully enclosed external fan type motor for vehicles in which cooling air is passed through a first ventilation path formed in the stator core by an external air fan provided on the counter-drive side. An internal air fan is provided inside the drive side, a second ventilation path is formed in the rotor core, and a third ventilation path is formed in the stator core, respectively, and the internal air is circulated through the second and third ventilation paths by the internal air fan. The ends of a plurality of adjacent first ventilation paths are surrounded by an oval space region provided in the counter-drive side bracket. The air from the external air fan flows into the first ventilation path through the oval space region and is discharged to the outside air through the exhaust holes of the drive side bracket.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In Patent Document 1, the first ventilation path that extends axially adjacent to each other is surrounded by an oval space region formed in the bracket. The air discharged radially outward from the external air fan moves circumferentially around the outer periphery of the external air fan and reaches the oval space region of the bracket, passes through the space region, is introduced into the first ventilation path, and is finally discharged to the outside air.

[0008] In order for air to pass through an oval space region, it is necessary to change the direction of the air flow from the circumferential direction of the outside air fan to the radially outer side. The air discharged from the outside air fan rotating at high speed and circulating around the outer circumference is at high speed and cannot suddenly change its direction. For this reason, the air concentrates on the downstream side in the rotation direction of the outside air fan in the oval space region. Further, due to this phenomenon, the flow rate of the air passing through the ones on the same downstream side among the plurality of first ventilation paths increases. As a result, in the first ventilation path with a large air flow rate, a large amount of air collides with the wall surface, the fluctuation of the sound wave becomes large, a large acoustic output is generated, and it is considered that the aerodynamic noise in the surroundings increases.

[0009] An object of the present invention is to provide a totally enclosed external fan-shaped motor having excellent quietness.

Means for Solving the Problems

[0010] In order to achieve the above problems, the totally enclosed external fan-shaped motor of the present invention is configured as described in the claims. In the claims, the citation of other claims in the claim in citation form is in the form of single-item citation for the sake of easy understanding of the description of the claim in citation form. However, the present invention includes forms in which a plurality of claims are cited (multi-item citation claims) and forms in which a plurality of multi-item citation claims are cited in the claim in citation form. Specifically, the totally enclosed external fan-shaped motor of the present invention, for example, houses a stator and a rotor in a totally enclosed frame, and an outside fan fixed to the rotation shaft of the rotor takes in outside air into the totally enclosed frame on the outside air side of the main board of the outside fan, and the air discharged from the outside fan is made to flow through a plurality of second ducts formed on the outer peripheral portion of the totally enclosed frame via an arc-shaped first duct formed at the axial end portion of the totally enclosed frame and discharged to the outside. It is a totally enclosed external fan-shaped motor, and a guide for taking in the air flowing in the circumferential direction into the first duct is provided so that the air discharged from the outside fan and flowing in the circumferential direction is dispersed and flows into the arc-shaped first duct in the circumferential direction.

Effects of the Invention

[0011] According to the present invention, a totally enclosed external fan-shaped motor having excellent quietness can be obtained. Configurations and effects other than those described above will be clarified by the following description of the embodiments.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description shows one specific example of the present invention, and the present invention is not limited to these descriptions. Various changes and modifications can be made by those skilled in the art within the scope of the technical idea disclosed in this specification. Also, in all the drawings for explaining the present invention, those having the same function are denoted by the same reference numerals, and the description may be omitted in the case of repetition.

[0014] A configuration example of a fully enclosed outer-sector motor for a vehicle (hereinafter referred to as a motor) 1 to which the present invention is applied will be described with reference to FIG. 1. The motor 1 of this embodiment is an induction motor. The motor 1 includes a stator 2 having a substantially cylindrical space at the axial center portion, and a substantially cylindrical rotor 3 disposed opposite to the stator 2 while maintaining a predetermined interval on the inner diameter side of the stator 2. The stator 2 includes a stator core 20 and a plurality of stator coils 22. The stator coils 22 are wound around a plurality of stator slots (not shown) formed around the stator core 20 and extending in the rotational axis direction. The stator core 20 is in contact with a part of the inner wall of a frame 4 which is a cylindrical member extending in the rotational axis direction, and is thereby relatively fixed to the frame 4. In FIG. 1, it is in contact with the inner wall of the frame 4 on the lower side and is in contact with the inner wall of the frame 4 at a plurality of locations in the circumferential direction.

[0015] End brackets 41a and 41b are attached to both ends of the frame 4. The frame 4 and the end brackets 41a and 41b constitute a fully closed frame. Bearings 37a and 37b are provided at the center of both ends of the fully closed frame, respectively. The fully closed frame is also provided with an inlet 81 which is a through hole for taking in air, and an outlet 82 for discharging the taken-in air. The fully closed frame is further provided with a first duct 91 on the outer peripheral portion of the end bracket 41a, and a second duct 92 at a position communicating with the first duct 91 on the outer peripheral portion of the frame 4. The first duct 91 and the second duct 92 constitute an exhaust duct 90.

[0016] The rotor 3 includes a rotor core 30 and a plurality of rotor bars 32. A plurality of through holes 301 through which air can flow are provided in the circumferential direction in the rotor core 30. Each rotor bar 32 is supported from both ends by end rings 33. The end rings 33 at both ends are held by retaining rings 34. Each rotor bar 32 is mechanically integrated by the end rings 33 and the retaining rings 34 to form a cage-shaped conductor. A shaft 36 is fitted into the central portion of the rotation axis of the rotor core 30. An inner fan 51 and an outer fan 52 which are centrifugal fans are fitted to the shaft 36. Both ends of the shaft are fitted to the inner rings of the bearings 37a and 37b. Thereby, the shaft 36 is held rotatably relative to the fully closed frame together with the rotor 3, the inner fan 51 and the outer fan 52.

[0017] AC power is supplied to the electric motor 1 to generate a rotating magnetic field while incurring various losses (heat generation). When the shaft 36 rotates, the internal fan 51 that rotates together causes the internal air 71 to flow in the direction of the arrow (dashed arrow) at each part, forming a circulating flow. Through this circulation, the internal air 71 transfers the heat of the main heat-generating parts such as the stator 2 and the rotor 3 to the frame 4, the main plate 52a of the external fan 52, and so on. Also, when the shaft 36 rotates, the external fan 52 that rotates together takes in air (external air 72) through the inlet 81. The external air 72 passes through the external fan 52 and is discharged in the circumferential direction, passes through the first duct 91, further passes through the second duct 92, and is discharged to the outside air from the outlet 82. During this process, the external air 72 exchanges heat on the surfaces of the frame 4, the main plate 52a of the external fan 52, etc., and suppresses their temperature rise while increasing its own temperature. Also, as shown in FIG. 1, a part of the outer circumference of the stator core 20 is directly cooled. Due to these series of actions, the temperature of the electric motor 1 is maintained within an appropriate range even when it rotates at high speed.

[0018] Next, with reference to FIGS. 2 to 4, the first duct 91 and the second duct 92 that constitute the exhaust duct 90 of this embodiment will be described in detail. In this embodiment, in a configuration where the air discharged from the external fan 52 is made to flow through the second duct 92 formed on the outer peripheral portion of the fully enclosed frame via the first duct 91 formed in the end bracket 41a that constitutes the fully enclosed frame, a guide is provided to take in the discharged air into the first duct 91 so that the air discharged from the external fan 52 and flowing in the circumferential direction does not concentrate and flow into a partial region in the circumferential direction of the first duct 91, that is, so that it flows in a dispersed manner in the circumferential direction.

[0019] A plurality of second ducts 92 are formed in the frame 4 in the circumferential direction. Adjacent second ducts 92 form a group, and a plurality of groups 92G of second ducts are formed on the entire circumference of the frame 4.

[0020] At a position of the end bracket 41a corresponding to the group 92G of the second ducts, an arcuate first duct 91 is provided for each of the groups 92G of the second ducts. The first duct 91 is not formed at a circumferential position where the group 92G of the second ducts is not formed. In other words, the plurality of first ducts 91 are divided by a portion protruding in the inner circumferential direction of the end bracket 41a. Guides 911, 912, 913, 914, 915, 916 are formed on the outer circumferential side of the first duct 91. That is, the guides 911, 912, 913, 914, 915, 916 are formed at positions facing the first duct 91 in the circumferential direction of the portion protruding in the inner circumferential direction of the end bracket 41a described above. When the space in the region where the guides 911, 912, 913, 914, 915, 916 are formed is regarded as a part of the first duct 91, the space of the first duct 91 is widened. In the present embodiment, the first duct 91 is formed in the end bracket 41a, and the guides 911, 912, 913, 914, 915, 916 are constituted by a wall surface facing the outer fan 52, that is, a wall surface of the end bracket on the side not in contact with the outside air of the end bracket 41a. The first duct 91 formed in the end bracket 41a has both a portion 917 extending in the radial direction of the outer fan 52 (or the frame 4) and a portion 918 extending in the axial direction of the frame 4 similar to the second duct 92, as shown in FIG. 3. Further, both of them are connected by a curved surface R1 and a curved surface R2. The portion 917 extending in the radial direction of the outer fan 52 and the portion 918 extending in the axial direction of the frame 4 form an arcuate space region of the first duct 91. The guides 911, 912, 913, 914, 915, 916 are guides for evenly flowing air into the region of the portion 918 extending in the axial direction of the frame 4 of the first duct 91, and as a result, evenly flowing air into the plurality of second ducts 92 constituting the group 92G of the second ducts.

[0021] Regions where the group 92G of the second ducts is formed, that is, two guides are formed so as to face each other in the circumferential direction with the region where the first duct 91 is formed interposed therebetween. For example, a guide 911 and a guide 912 are formed so as to face each other in the circumferential direction on both circumferential sides of the first duct 91. When viewed with respect to the guide 911 and the guide 912 continuous with this single first duct 91, the interval length L between the guide 911 and the guide 912 is configured to become longer as it approaches the outer fan 52. That is, the circumferential width (the frontage of the first duct) of the first duct is configured to become wider as it approaches the axis of the outer fan 52. Here, the interval length L of the guides is the length in the direction of a line orthogonal to the line extending radially from the center of the rotation axis and passing through the middle between the guides. Note that the configurations of the interval lengths between the guide 913 and the guide 914, and between the guide 915 and the guide 916 are the same.

[0022] The guide 911 serves as a guide for the flow of air to the first duct 91 when the outer fan 52 rotates counterclockwise on the drawing of FIG. 2, and the guide 912 serves as a guide for the flow of air to the first duct 91 when the outer fan 52 rotates clockwise on the drawing of FIG. 2. Note that as shown in FIG. 4, when there is a region C where the second duct 92 is not constant in the circumferential direction (that is, the first duct is also not constant in the circumferential direction in the region C), the guide 911 and the guide 916 are guides for the flow of air to the first duct 91 corresponding to the group 92G of the second ducts adjacent to the region C.

[0023] In other words, configuring the interval length L of the guides to become longer as it approaches the outer fan 52 means that the guides 911 and 912 are configured to approach the outer fan 52 as they move away from the group 92G of the second ducts in the circumferential direction. That is, when viewed with respect to the guide 912, on the drawing of FIG. 2, it is configured to approach the outer fan 52 as it moves away from the leftmost second duct 92 of the group 92G of the second ducts on the right side of the guide 912 in the circumferential direction. Also, when viewed with respect to the guide 913, on the drawing of FIG. 2, it is configured to move away from the outer fan 52 as it approaches the rightmost second duct 92 of the group 92G of the second ducts on the left side of the guide 913 in the circumferential direction. Also, as shown in FIG. 4, in this embodiment, the guide 911 is composed of an inclined surface S1 and an inclined surface S2. The inclined surface S1 is an inclined surface that is gentler than the inclined surface S2. The other guides 912, 913, 914, 915, 916 are also configured in the same way. The guides 911, 912, 913, 914, 915, 916 may be composed of one inclined surface or may be formed in a stepped shape. Further, the inclined surface may be formed as a curved surface instead of a flat surface.

[0024] Next, the flow and effects of the outside air 72 will be described with reference to FIG. 3. When the outer fan 52 rotates with the rotation of the shaft 36, the outside air 72 is first taken in from the inlet 81 shown in FIG. 1 in the direction of the flow 72a. Then, after changing the direction like the flow 72b, it is discharged from the inner peripheral side of the outer fan 52 to the outer peripheral side. Next, as indicated by the arrow of the flow 72c, while moving in the circumferential direction in the gap between the outer fan 52 and the fully closed frame, it flows into one of the second ducts 92 via the first duct 91 and is discharged through the second duct in the direction of the flow 72d.

[0025] Among the above flows, since the flow 72c is configured such that the guide (guide 915 in FIG. 3) moves away from the outer fan 52 as it approaches the group 92G of the second ducts on the left side of the drawing, the outside air 72 discharged from the outer fan 52 and circulating in the tangential direction of the outer fan 52 is smoothly (without the need to suddenly change the direction) guided to one of the second ducts 92 via the first duct 91. Therefore, it is possible to avoid the phenomenon that the air flow rate in the second duct 92 downstream in the rotation direction of the outer fan 52 becomes relatively large. That is, since the air discharged from the outer fan 52 and circulating at high speed around the outer periphery is easily introduced smoothly into the first duct 91, the air flow rates to the plurality of second ducts 92 in the group 92G of the second ducts corresponding to the first duct 91 are substantially equalized.

[0026] In a totally enclosed external fan motor, the aerodynamic noise observed in the surroundings is the propagation of the acoustic output generated as a result of the flow of the external air 72 repeatedly colliding with and separating from the surfaces of the components, and the greater the air velocity, the greater the noise. According to this embodiment, it is possible to suppress the phenomenon in which the air flow rate of a specific second duct 92 becomes relatively large (i.e., the air velocity relatively increases). As a result, the maximum value of the acoustic output can also be kept small, so that the noise observed externally can be suppressed.

Explanation of Reference Numerals

[0027] 1: Rotating electrical machine, 2: Stator, 3: Rotor, 4: Frame, 20: Stator core, 21: Stator slot, 22: Stator coil, 30: Rotor core, 32: Rotor bar, 33: End ring, 34: Retaining ring, 36: Shaft, 37a, 37b: Bearing, 41a, 41b: End bracket, 51: Inner fan, 52: Outer fan, 52a: Main plate, 71: Internal air, 72: External air, 72a, 72b, 72c, 72d: Flow, 81: Inlet, 82: Outlet, 90: Exhaust duct, 91: First duct, 92: Second duct, 92G: Group of second ducts, 301: Through hole, 911, 912, 913, 914, 915, 916: Guide, 917: Portion extending in the radial direction of the frame, 918: Portion extending in the axial direction of the frame, L: Interval length of the guide, R1, R2: Curved surface.

Claims

1. A stator and a rotor are housed within a fully enclosed frame, and an outer fan fixed to the rotation axis of the rotor takes in outside air into the fully enclosed frame on the outside air side of the main board of the outer fan, and discharges the air discharged from the outer fan through an arc-shaped first duct formed at an axial end portion of the fully enclosed frame to flow through a plurality of second ducts formed at the outer peripheral portion of the fully enclosed frame and be discharged to the outside. A fully enclosed outer fan-shaped motor, wherein a guide for taking in the air flowing in the circumferential direction into the first duct is provided so that the air discharged from the outer fan and flowing in the circumferential direction is dispersed in the circumferential direction and flows into the arc-shaped first duct, the guide is constituted by a wall surface facing the outer fan, the first duct is formed within an end bracket constituting the fully enclosed frame, and the guide is constituted by a wall surface of the end bracket on the side not in contact with the outside air, the end bracket is formed such that a portion corresponding to a region where the plurality of second ducts are not formed protrudes in the inner circumferential direction, the circumferential surface of the portion of the end bracket protruding in the inner circumferential direction faces the first duct, the guide is formed at a location facing the first duct in the circumferential direction of the portion of the end bracket protruding in the inner circumferential direction, and the guide is formed so as to expand the space region of the first duct. A fully enclosed outer fan-shaped motor.

2. In the fully enclosed outer fan-shaped motor according to Claim 1, the guide is formed so as to face each other in the circumferential direction on both sides of the first duct corresponding to the region where the second duct is formed, and the circumferential interval between the guides formed so as to face each other in the circumferential direction is formed so as to widen toward the rotation axis. A fully enclosed outer fan-shaped motor.

3. In the fully enclosed outer fan-shaped motor according to Claim 1 or 2, the first duct includes a portion extending in the radial direction of the outer fan and a portion extending in the axial direction of the fully enclosed frame, and the portion of the first duct extending in the axial direction of the fully enclosed frame communicates with the plurality of second ducts. A fully enclosed outer fan-shaped motor.

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