JP7760095B2 - Filter device and electric motor - Google Patents

Description

The present disclosure relates to a filter device and an electric motor.

Some onboard equipment in railway vehicles uses outside air flowing in through air intakes to cool the interior, specifically electronic components that generate heat when powered on. To prevent damage to the electronic components caused by contact with foreign matter such as dust and moisture in the outside air, the onboard equipment is equipped with a filter located outside the air intake. This type of onboard equipment is disclosed in Patent Document 1.

The air compressor for railway vehicles disclosed in Patent Document 1 uses the rotation of a cooling fan to draw outside air into the housing case as cooling air, filtered through the filter portion of the filter unit. The filter portion has an uneven shape with alternating convex and concave portions facing outward and inward, respectively, of the housing case.

JP 2011-153534 A

The filter section provided in the railcar air compressor disclosed in Patent Document 1 has a continuous V-shaped concave and convex shape in horizontal cross section. The plate-shaped filter material forming the V-shape is oriented intersecting the direction of outside air inflow. As the filter section is used for a long time, foreign matter may adhere to the edges of the ventilation holes in the plate-shaped filter material oriented intersecting the inflow direction, causing the ventilation holes to become clogged. When the ventilation holes become clogged over time, the air flow path through the filter section decreases, causing a sudden drop in the flow rate of the filter section and a sudden decline in the cooling performance of the railcar air compressor.

This disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a filter device and an electric motor equipped with a filter device that can suppress a sudden decrease in flow rate due to aging.

To achieve the above object, the present disclosure provides a filter device that is attached to onboard equipment of a railway vehicle that cools the interior with outside air taken in through an air intake, covering the air intake from the outside. The filter device removes foreign matter from the incoming outside air and guides the removed outside air to the air intake. The filter device includes a first filtering member having a plurality of first front surfaces, a plurality of first rear surfaces, and a plurality of first side surfaces. The main surfaces of each of the first front surfaces intersect with the inflow direction of the outside air. Adjacent first front surfaces are positioned with a first gap between them. The main surfaces of each of the first rear surfaces face the first gap between two adjacent first front surfaces. The first rear surfaces are positioned downstream of the first front surfaces in the inflow direction, spaced apart from each other. The first side surfaces connect the first rear surfaces to each of the two first front surfaces positioned across the first gap toward which the main surfaces of the first rear surfaces face. The distance between two first side portions connected to the same first rear portion is such that the distance downstream in the inflow direction is greater than the distance upstream in the inflow direction. The total surface area of the first side portions is greater than the total surface area of each of the first front portion and the first rear portion.

The filter device of the present disclosure comprises a first filtering member having a plurality of first front portions whose principal surfaces intersect with the inflow direction, a plurality of first back portions whose principal surfaces face first gaps between the first front portions, and a plurality of first side portions connecting the first back portions to each of the two first front portions located on either side of the first gaps toward which the principal surfaces of the first back portions face. The distance between the two first side portions connected to the same first back portion is such that the length downstream in the inflow direction is equal to or greater than the length upstream in the inflow direction, and the total surface area of the first side portions is greater than the total surface area of the first front portions and the first back portions. This configuration makes it difficult for foreign matter to clog the first side portions, resulting in a filter device that suppresses a sudden decrease in flow rate due to aging.

1 is a perspective view of an electric motor according to a first embodiment of the present invention; 1 is a cross-sectional view of an electric motor according to a first embodiment of the present invention; 3 is a cross-sectional view of the electric motor according to the first embodiment taken along line III-III in FIG. 2 ; 1 is a side view of an electric motor according to a first embodiment of the present invention; 5 is a cross-sectional view of the filter device according to the first embodiment taken along line VV in FIG. 4. 6 is a cross-sectional view of the filter device according to the first embodiment taken along line VI-VI in FIG. 4. 10 is a cross-sectional view of a filter device according to a second embodiment. 10 is a cross-sectional view of a filter device according to a second embodiment. 1 is a cross-sectional view of a first modified example of a filter device according to an embodiment; 10 is a cross-sectional view of a second modified example of the filter device according to the embodiment; 10 is a side view of an electric motor including a third modified example of a filter device according to an embodiment; 10 is a side view of an electric motor including a fourth modified example of a filter device according to an embodiment; 10 is a side view of an electric motor including a filter device according to a fifth modification of the embodiment; FIG. 10 is a cross-sectional view of a sixth modified example of the filter device according to the embodiment. 13 is a front view of a power conversion device including a seventh modified example of a filter device according to an embodiment.

The filter device and electric motor according to the embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that in the drawings, identical or equivalent parts are designated by the same reference numerals.

(Embodiment 1)
A filter device and a motor equipped with the filter device according to a first embodiment will be described using an electric motor, which is a type of on-board equipment for a railway vehicle, as an example. The electric motor 1 shown in Figures 1 and 2 is an open-type electric motor for driving a railway vehicle. The electric motor 1 is attached to the underfloor of the railway vehicle by means of mounting members (not shown). The electric motor 1 takes in outside air, which is air outside the electric motor 1, and cools the components of the electric motor 1 by flowing the air inside the electric motor 1. The electric motor 1 is equipped with a filter device 31 to prevent foreign matter such as dust and moisture contained in the outside air from entering the inside.

In Figures 1 and 2, the Z-axis direction indicates the vertical direction when the railway vehicle is positioned horizontally. The Y-axis direction indicates the width direction of the railway vehicle. The X-axis direction indicates the direction of travel of the railway vehicle. In other words, the railway vehicle travels in the positive X-axis direction or the negative X-axis direction. The X-axis, Y-axis, and Z-axis are perpendicular to each other. This also applies to subsequent figures.

Electric motor 1 comprises a shaft 14 rotatably supported about a rotation axis AX shown by a dot-dash line in Figures 1 and 2, a rotor 15 located radially outward of shaft 14 and rotating integrally with shaft 14, a stator 16 facing rotor 15 at a distance in the radial direction, bearings 17 and 18 that rotatably support shaft 14, and a fan 19 attached to shaft 14 and rotating integrally with shaft 14. The radial direction is perpendicular to rotation axis AX.

The electric motor 1 further includes a frame 11 that houses the rotor 15, stator 16, bearings 17, 18, and fan 19 with the shaft 14 inserted therethrough; a first bracket 12 that has an intake hole 12a formed on its end face that intersects with the extension direction of the rotation axis AX; a second bracket 13 that faces the first bracket 12 in the extension direction of the rotation axis AX across the rotor 15 and stator 16 and has an exhaust hole 13a formed on its outer peripheral surface; and a filter device 31 attached to the first bracket 12.

In the electric motor 1 having the above configuration, the rotation of the fan 19 causes outside air to flow into the interior of the electric motor 1 through the intake holes 12a formed in the first bracket 12. As shown by the solid arrows in Figure 2, the outside air flows through the gap 20 between the rotor 15 and the stator 16, and then flows out of the electric motor 1 through the exhaust holes 13a formed in the second bracket 13. The above-mentioned flow of outside air cools the components of the electric motor 1, specifically the rotor 15, stator 16, and bearings 17 and 18.

Details of each part of the electric motor 1 will be explained. The frame 11 is fixed to the underfloor of the railway vehicle by mounting members. The frame 11 has a cylindrical shape with openings at both ends. The openings at both ends of the frame 11 are closed by a first bracket 12 and a second bracket 13.

The first bracket 12 is attached to one end of the frame 11, specifically the end on the negative side of the Y axis. As shown in Figure 3, which is a cross-sectional view taken along line III-III in Figure 2, the first bracket 12 has an intake hole 12a formed therein for allowing outside air to flow in. The intake hole 12a is preferably formed in a position facing the flow path of outside air inside the electric motor 1, specifically, the gap 20.

As shown in Figures 1 and 2, the second bracket 13 faces the first bracket 12 in the Y-axis direction, sandwiching the rotor 15 and stator 16 between them. The second bracket 13 is attached to the other end of the frame 11, specifically the end on the positive Y-axis side. An exhaust hole 13a is formed on the outer peripheral surface of the second bracket 13, allowing outside air that has flowed in through the intake hole 12a to flow out to the outside.

One end of the shaft 14 near the second bracket 13 is connected to the axle of the railway vehicle via a coupling and gears (not shown). The rotation of the shaft 14 powers the railway vehicle.

The rotor 15 has a rotor core 15a attached to the shaft 14 and rotor bars 15b inserted into slots formed on the outer surface of the rotor core 15a.

The stator 16 has a stator core 16a attached to the inner circumferential surface of the frame 11 and a stator coil 16b inserted into slots formed in the stator core 16a. The stator core 16a faces the rotor core 15a at a radial distance.

Bearing 17 is held by first bracket 12 and rotatably supports shaft 14. Bearing 18 is held by second bracket 13 and rotatably supports shaft 14.

The fan 19 is attached to the shaft 14 between the stator 16 and the second bracket 13 and rotates integrally with the shaft 14. As the shaft 14 rotates, air outside the motor 1 flows into the motor 1 through the intake holes 12a, and the air flows out through the exhaust holes 13a.

As shown in Figure 4, which shows the electric motor 1 viewed in the positive direction of the Y axis, the filter device 31 is attached to the first bracket 12 so as to cover the intake hole 12a formed in the first bracket 12. In embodiment 1, the filter device 31 is attached to the first bracket 12 by fastening with fastening members.

The filter device 31 removes foreign matter from the incoming outside air and guides the removed outside air to the intake port 12a. As a result, the outside air from which the foreign matter has been removed by the filter device 31 flows into the interior of the electric motor 1 through the intake port 12a. In embodiment 1, the outside air flows in along the positive Y-axis direction. The filter device 31 removes foreign matter from the outside air flowing in in the positive Y-axis direction and guides the removed outside air to the intake port 12a located on the positive Y-axis side of the filter device 31.

The filter device 31 includes a fixed frame 40 fixed to the first bracket 12 and a first filter member 41 attached to the fixed frame 40 to prevent foreign matter contained in the outside air from entering the interior of the electric motor 1. In the first embodiment, the fixed frame 40 and the first filter member 41 have a partial ring shape extending circumferentially around the rotation axis AX.

As shown in Figures 4 and 5, which is a cross-sectional view taken along line V-V in Figure 4, the first filter member 41 has a radially extending concave-convex shape perpendicular to the rotation axis AX. Specifically, as shown in Figure 5, the first filter member 41 has multiple first front surface portions 42 whose main surfaces 42a intersect with the inflow direction of outside air, i.e., the positive direction of the Y axis. Adjacent first front surface portions 42 are positioned with a first gap 45 between them. The first filter member 41 has multiple first back surface portions 43 whose main surfaces 43a face the first gap 45 between adjacent first front surface portions 42 and are positioned spaced apart downstream of the first front surface portions 42 in the inflow direction, and multiple first side surface portions 44 connecting the first back surface portion 43 to each of the two first front surface portions 42 positioned with the first gap 45 between them facing the main surfaces 43a of the first back surface portions 43.

In embodiment 1, the first filter member 41 has a plurality of first front surface portions 42 whose main surfaces 42a are perpendicular to the Y-axis direction, and a plurality of first back surface portions 43 whose main surfaces 43a are perpendicular to the Y-axis direction.

As shown in Figure 4, the multiple first front surface portions 42 are spaced apart in the circumferential direction around the rotation axis AX. In embodiment 1, each first front surface portion 42 extends in the radial direction and the circumferential direction perpendicular to the rotation axis AX.

The multiple first back portions 43 are positioned at intervals in the circumferential direction around the rotation axis AX. In embodiment 1, each first back portion 43 extends in the radial direction and the circumferential direction perpendicular to the rotation axis AX.

Each first side surface portion 44 smoothly connects the first front surface portion 42 and the first rear surface portion 43. In embodiment 1, each first side surface portion 44 has a main portion extending in the extension direction and radial direction of the rotation axis AX, and an end portion connecting the main portion to the first front surface portion 42 or the first rear surface portion 43.

The distance between two first side portions 44 connected to the same first back surface portion 43 is such that the length W11 downstream in the inflow direction is equal to or greater than the length W12 upstream in the inflow direction. Specifically, the circumferential length W11 of the gap between two adjacent first side portions 44 downstream in the inflow direction is equal to or greater than the circumferential length W12 of the gap between two adjacent first side portions 44 upstream in the inflow direction. In other words, the angle formed between the flat portion of the main surface 42a of the first front surface portion 42 and the flat portion of the main surface 44a of the first side portion 44 is equal to or greater than 90 degrees. In embodiment 1, the length W11 downstream in the inflow direction is equal to the length W12 upstream in the inflow direction. Therefore, the first side portion 44 is oriented with its main surface 44a aligned along the inflow direction.

The total surface area of the first side portion 44 is greater than the total surface area of the first front portion 42 and the first back portion 43. Specifically, the total surface area of the main surface 44a of the first side portion 44 is greater than the total surface area of the main surface 42a of the first front portion 42 and the main surface 43a of the first back portion 43.

The main surface 42a of the first front surface portion 42, the main surface 43a of the first back surface portion 43, and the main surface 44a of the first side surface portion 44 shown in FIG. 5 are each the surface on the upstream side of the outside air passing through the filter device 31, of the two main surfaces. As an example, the main surface 42a of the first front surface portion 42 is the surface on the negative Y-axis side of the first front surface portion 42. Similarly, the main surface 43a of the first back surface portion 43 is the surface on the negative Y-axis side of the first back surface portion 43. The main surface 44a of the first side surface portion 44 located at the right end in FIG. 5 is the surface on the positive X-axis side of the first side surface portion 44. The main surface 44a of the first side surface portion 44 located at the left end in FIG. 5 is the surface on the negative X-axis side of the first side surface portion 44.

In embodiment 1, the first filter member 41 is formed by repeatedly bending a mesh-like first metal member into a U-shape while alternating the direction of the bending to form a bellows shape. The first metal member is made of, for example, stainless steel. Specifically, the first filter member 41 is formed by repeatedly bending a stainless steel mesh into a U-shape.

The filter device 31 is obtained by bending the entire first filter member 41, which has been repeatedly bent into a U-shape, into an arc with the bending lines of the U-shape aligned radially, and attaching it to the inner surface of the fixed frame 40. The inner surface of the fixed frame 40 has protrusions that engage with the mesh of the first filter member 41. As a result, the first filter member 41 is attached to the fixed frame 40.

By forming the first filter member 41 from a mesh-like first metal member, ventilation holes 42b, 43b, and 44b are formed in the first front portion 42, the first back portion 43, and the first side portion 44, respectively, as shown in Figure 6, which is a cross-sectional view taken along line VI-VI in Figure 4.

As shown by the solid arrows in Figure 6, outside air passes through one of the ventilation holes 42b, 43b, or 44b, passes through the filter device 31, and then flows into the interior of the motor 1 through the intake hole 12a as shown in Figure 2, passes through the gap 20, and then flows out to the outside through the exhaust hole 13a.

As the filter is used for a long time, foreign matter may become clogged in the ventilation holes through which outside air passes. In the filter device 31, the main surface 42a of the first front portion 42 and the main surface 43a of the first rear portion 43 are positioned perpendicular to the inflow direction, and the first side portion 44 is disposed with its main surface 44a oriented along the inflow direction. More outside air flows through the ventilation holes 42b formed on the main surface 42a of the first front portion 42, which are perpendicular to the inflow direction of outside air, and the ventilation holes 43b formed on the main surface 43a of the first rear portion 43. Therefore, as the filter device 31 is used for a long time, the ventilation holes 44b formed on the first side portion 44, whose main surface 44a is oriented along the inflow direction, are less likely to become clogged with foreign matter than the ventilation holes 42b formed on the first front portion 42 and the ventilation holes 43b formed on the first rear portion 43.

As described above, the filter device 31 according to embodiment 1 includes a first filter member 41 having a plurality of first front surfaces 42, a plurality of first rear surfaces 43, and a plurality of first side surfaces 44 connecting the first rear surfaces 43 to each of the two first front surfaces 42 positioned on either side of a first gap 45 toward which the main surfaces of the first rear surfaces 43 face. The distance between the two first side surfaces 44 connected to the same first rear surface 43 is such that the length downstream in the inflow direction is equal to or greater than the length upstream in the inflow direction, and the total surface area of the first side surfaces 44 is greater than the total surface area of the first front surfaces 42 and the first rear surfaces 43.

The distance between two first side portions 44 connected to the same first rear portion 43 is such that the length downstream in the inflow direction is equal to or greater than the length upstream in the inflow direction. The total surface area of the first side portions 44, which are less susceptible to clogging, is greater than the total surface area of the first front portion 42 and the first rear portion 43. Therefore, the filter device 31 is less susceptible to clogging than a filter with a continuous V-shaped concave-convex shape. This results in a filter device 31 in which a sudden decrease in flow rate due to aging is suppressed. As a result, an electric motor 1 in which a sudden decrease in cooling performance due to aging is suppressed is obtained.

As described above, foreign matter is less likely to clog the first side portion 44, and a sudden decrease in flow rate due to aging is suppressed, which extends the period from when the filter device 31 begins to be used until it needs to be cleaned to remove foreign matter. As a result, the maintenance cycle for the filter device 31 is extended, improving maintainability.

Since the first front portion 42, the first back portion 43, and the first side portion 44 form an uneven shape, the surface area of the first filter member 41 is larger than that of a flat filter member, and the total area of the ventilation holes is therefore larger, resulting in a larger flow rate.

(Embodiment 2)
The configuration of the filter device is not limited to the above example. A filter device including multiple filter members will be described in Embodiment 2, focusing on differences from Embodiment 1. The filter device 32 shown in FIG. 7 includes a second filter member 51 in addition to the configuration of the filter device 31 according to Embodiment 1. The filter device 32 removes foreign matter from the incoming outside air using the first filter member 41 and the second filter member 51, and guides the outside air from which the foreign matter has been removed to the air intake vent 12a. As in Embodiment 1, the positive direction of the Y axis is the direction in which the outside air flows in.

Similar to the first filter member 41, the second filter member 51 has a radially extending concave-convex shape perpendicular to the rotation axis AX. Specifically, the second filter member 51 has a plurality of second front surface portions 52 whose main surfaces 52a face different first front surface portions 42. Adjacent second front surface portions 52 are positioned with a second gap 55 between them. The second filter member 51 has a plurality of second back surface portions 53 whose main surfaces 53a face the second gap 55 between adjacent second front surface portions 52 and are positioned spaced apart downstream of the second front surface portions 52 in the inflow direction, and a plurality of second side surface portions 54 connecting the second back surface portions 53 to each of the two second front surface portions 52 positioned with the second gap 55 between them facing the main surfaces 53a of the second back surface portions 53.

In embodiment 2, the second filter member 51 has a plurality of second front surface portions 52 whose main surfaces 52a are perpendicular to the Y-axis direction, and a plurality of second back surface portions 53 whose main surfaces 53a are perpendicular to the Y-axis direction.

The convex portion of the second filter member 51 is located downstream in the inflow direction of the convex portion of the first filter member 41. The concave portion of the second filter member 51 is located downstream in the inflow direction of the concave portion of the first filter member 41. Specifically, the main surfaces 52a of the second front surface portions 52 face toward different first front surface portions 42, and the main surfaces 53a of the second back surface portions 53 face toward different first back surface portions 43.

The multiple second front surface portions 52 are spaced apart in the circumferential direction around the rotation axis AX. In embodiment 2, each second front surface portion 52 extends in the radial and circumferential directions perpendicular to the rotation axis AX.

The multiple second back portions 53 are positioned at intervals in the circumferential direction around the rotation axis AX. In embodiment 2, each second back portion 53 extends in the radial and circumferential directions perpendicular to the rotation axis AX.

Each second side surface portion 54 smoothly connects the second front surface portion 52 and the second back surface portion 53. In embodiment 2, each second side surface portion 54 has a main portion extending in the extension direction and radial direction of the rotation axis AX, and an end portion connecting the main portion to the second front surface portion 52 or the second back surface portion 53.

The distance between two second side portions 54 connected to the same second back surface portion 53 is such that the length W21 downstream in the inflow direction is equal to or greater than the length W22 upstream in the inflow direction. Specifically, the circumferential length W21 of the gap between two circumferentially adjacent second side portions 54 downstream in the inflow direction is equal to or greater than the circumferential length W22 of the gap between two circumferentially adjacent second side portions 54 upstream in the inflow direction. In other words, the angle formed between the flat portion of the main surface 52a of the second front surface portion 52 and the flat portion of the main surface 54a of the second side portion 54 is equal to or greater than 90 degrees. In embodiment 2, the length W21 downstream in the inflow direction is equal to the length W22 upstream in the inflow direction. Therefore, the second side portion 54 is oriented with its main surface 54a aligned along the inflow direction.

The total surface area of the second side portion 54 is greater than the total surface area of the second front portion 52 and the second back portion 53. Specifically, the total surface area of the main surface 54a of the second side portion 54 is greater than the total surface area of the main surface 52a of the second front portion 52 and the main surface 53a of the second back portion 53.

The main surface 52a of the second front surface portion 52, the main surface 53a of the second back surface portion 53, and the main surface 54a of the second side surface portion 54 are each the surface on the upstream side of the outside air passing through the filter device 32, of the two main surfaces. As an example, the main surface 52a of the second front surface portion 52 is the surface on the negative Y-axis side of the second front surface portion 52. Similarly, the main surface 53a of the second back surface portion 53 is the surface on the negative Y-axis side of the second back surface portion 53. The main surface 54a of the second side surface portion 54 located at the right end in Figure 7 is the surface on the positive X-axis side of the first side surface portion 54. The main surface 54a of the second side surface portion 54 located at the left end in Figure 7 is the surface on the negative X-axis side of the second side surface portion 54.

In embodiment 2, the second filter member 51 is formed by repeatedly bending a mesh-like second metal member into a U-shape while alternating the direction of the bending to form a bellows shape. The second metal member is made of the same material as the first metal member, for example, stainless steel. Specifically, the second filter member 51 is formed by repeatedly bending a stainless steel mesh into a U-shape.

The entire first filter member 41 and the entire second filter member 51, which have been repeatedly folded into a U-shape, are then bent into an arc so that the folding lines formed when folding into a U-shape coincide with the radial direction, and attached to the inner surface of the fixed frame 40 to obtain the filter device 32. Protrusions are formed on the inner surface of the fixed frame 40, and the mesh of the first filter member 41 and the second filter member 51 engage with the protrusions. As a result, the first filter member 41 and the second filter member 51 are attached to the fixed frame 40.

By forming the second filter member 51 from a mesh-like second metal member, ventilation holes 52b, 53b, and 54b are formed in the second front portion 52, second back portion 53, and second side portion 54, respectively, as shown in Figure 8.

As shown by the solid arrows in Figure 8, outside air passes through one of ventilation holes 42b, 43b, or 44b, then one of ventilation holes 52b, 53b, or 54b, and then passes through the filter device 32. After passing through the filter device 32, the outside air flows into the interior of the electric motor 1 through the intake hole 12a, passes through the gap 20, and then flows out to the outside through the exhaust hole 13a.

It is preferable that the mesh size of the first filter member 41 be larger than that of the second filter member 51. Specifically, it is preferable that the sizes of the ventilation holes 42b, 43b, and 44b be larger than the sizes of the ventilation holes 52b, 53b, and 54b, respectively.

It is preferable that the mesh spacing of the first filter member 41 be wider than the mesh spacing of the second filter member 51. Specifically, the spacing between adjacent ventilation holes 42b is wider than the spacing between adjacent ventilation holes 52b. Similarly, the spacing between adjacent ventilation holes 43b is wider than the spacing between adjacent ventilation holes 53b. Similarly, the spacing between adjacent ventilation holes 44b is wider than the spacing between adjacent ventilation holes 54b.

Specifically, the filter device 32 is obtained by attaching a first filter member 41, which is formed by repeatedly bending a stainless steel mesh with large mesh and thick wire diameter into a U-shape, and a second filter member 51, which is formed by bending a stainless steel mesh with small mesh and thin wire diameter into a U-shape, to a fixed frame 40.

With the above configuration, the rigidity of the first filter member 41 is higher than that of the second filter member 51. Furthermore, the second filter member 51 is a filter with a finer mesh than the first filter member 41. Increasing the rigidity of the first filter member 41 prevents the filter device 32 from being damaged by hard foreign matter such as stones and sand. By making the second filter member 51 a filter with a finer mesh than the first filter member 41, small foreign matter contained in the outside air that has passed through the first filter member 41, such as iron powder, pollen, and PM (Particulate Matter) 2.5, can be removed by the second filter member 51.

As the filter is used for a long time, foreign matter may become clogged in the ventilation holes through which outside air passes. In the filter device 32, the main surface 52a of the second front portion 52 and the main surface 53a of the second back portion 53 are positioned perpendicular to the inflow direction, and the second side portion 54 is provided with its main surface 54a oriented along the inflow direction. More outside air flows through the ventilation holes 52b formed on the main surface 52a of the second front portion 52, which are perpendicular to the inflow direction of outside air, and the ventilation holes 53b formed on the main surface 53a of the second back portion 53. Therefore, as the filter device 32 is used for a long time, the ventilation holes 54b formed on the second side portion 54, whose main surface 54a is oriented along the inflow direction, are less likely to become clogged with foreign matter than the ventilation holes 52b formed on the second front portion 52 and the ventilation holes 53b formed on the second back portion 53.

As described above, the filter device 32 of embodiment 2 comprises a first filter member 41 having a plurality of first front surface portions 42, a plurality of first rear surface portions 43, and a plurality of first side surface portions 44 connecting the first rear surface portion 43 to each of the two first front surface portions 42 located on either side of the first gap 45 toward which the main surface of the first rear surface portion faces, and a second filter member 51 having a plurality of second front surface portions 52, a plurality of second rear surface portions 53, and a plurality of second side surface portions 54 connecting the second rear surface portion 53 to each of the two second front surface portions 52 located on either side of the second gap 55 toward which the main surface of the second rear surface portion 53 faces.

The distance between two first side portions 44 connected to the same first rear portion 43 is such that the length downstream in the inflow direction is equal to or greater than the length upstream in the inflow direction, and the total surface area of the first side portions 44 is greater than the total surface area of the first front portion 42 and the first rear portion 43. The distance between two second side portions 54 connected to the same second rear portion 53 is such that the length downstream in the inflow direction is equal to or greater than the length upstream in the inflow direction, and the total surface area of the second side portions 54 is greater than the total surface area of the second front portion 52 and the second rear portion 53.

The distance between two first side sections 44 connected to the same first rear section 43 and the distance between two second side sections 54 connected to the same second rear section 53 are such that the distance downstream in the inflow direction is equal to or greater than the distance upstream in the inflow direction. The total surface area of the first side sections 44, which are less susceptible to clogging, is greater than the total surface area of the first front section 42 and the first rear section 43. The total surface area of the second side sections 54, which are less susceptible to clogging, is greater than the total surface area of the second front section 52 and the second rear section 53. Therefore, the filter device 32 is less susceptible to clogging than a filter with a continuous V-shaped concave-convex shape. This results in a filter device 32 that is less susceptible to sudden decreases in flow rate due to aging. As a result, an electric motor 1 is obtained that is less susceptible to sudden decreases in cooling performance due to aging.

As described above, foreign matter is less likely to clog the first side surface portion 44 and the second side surface portion 54, and a sudden decrease in flow rate due to aging is suppressed, which extends the period from when the filter device 32 begins to be used until it needs to be cleaned to remove foreign matter. As a result, the maintenance cycle for the filter device 32 is extended, improving maintainability.

By making the rigidity of the first filter member 41 greater than that of the second filter member 51 and making the second filter member 51 a filter with a finer mesh than the first filter member 41, a filter device 32 is obtained that prevents the inflow of small foreign matter such as iron powder, pollen, and PM2.5 while suppressing damage caused by large foreign matter such as stones and sand.

By positioning the convex portion of the second filter member 51 downstream of the convex portion of the first filter member 41 in the inflow direction and the concave portion of the second filter member 51 downstream of the concave portion of the first filter member 41 in the inflow direction, a significant increase in the width of the inflow direction of the filter device 32 equipped with the first filter member 41 and the second filter member 51 is prevented compared to the filter device 31.

This disclosure is not limited to the above-described embodiments. The structure and shape of the filter device may be any structure and shape that can prevent foreign matter from entering the electric motor 1 and that prevents a sudden decrease in flow rate over time.

As an example, in the first filter member 41 provided in the filter device 33 shown in Figure 9, the distance between two first side portions 44 connected to the same first back surface portion 43 is such that the length W31 downstream in the inflow direction is greater than the length W32 upstream in the inflow direction. The length W31 downstream in the inflow direction can be greater than the length W32 upstream in the inflow direction, as long as the two first side portions 44 connected to the same first front surface portion 42 do not abut. The filter device 33 may further include a second filter member 51 formed in the same manner as the first filter member 41.

As another example, the filter device 34 shown in Figure 10 includes multiple filtration units each having a first filtration member 41 and a second filtration member 51. In detail, the filter device 34 includes a filtration unit 61 having a first filtration member 41 and a second filtration member 51, and a filtration unit 62 having a first filtration member 41 and a second filtration member 51. The filtration units 61 and 62 are aligned in the inflow direction, in other words, in the positive direction of the Y axis.

The first filter member 41 of the filter unit 62 located downstream in the inflow direction preferably has a finer mesh than the second filter member 51 of the filter unit 61 located upstream in the inflow direction. Specifically, the size of the ventilation holes 42b formed in the first front surface 42 of the first filter member 41 of the filter unit 62 is preferably smaller than the ventilation holes 52b formed in the second front surface 52 of the second filter member 51 of the filter unit 61. The spacing between the ventilation holes 42b formed in the first front surface 42 of the first filter member 41 of the filter unit 62 is preferably narrower than the spacing between the ventilation holes 52b formed in the second front surface 52 of the second filter member 51 of the filter unit 61.

Similarly, the size of the ventilation holes 43b formed in the first rear portion 43 of the first filter member 41 of the filtration unit 62 is preferably smaller than the ventilation holes 53b formed in the second rear portion 53 of the second filter member 51 of the filtration unit 61. The spacing between the ventilation holes 43b formed in the first rear portion 43 of the first filter member 41 of the filtration unit 62 is preferably narrower than the spacing between the ventilation holes 53b formed in the second rear portion 53 of the second filter member 51 of the filtration unit 61.

In the filter device 34, outside air passes through the first filter member 41 and second filter member 51 of the filter unit 61 and the first filter member 41 and second filter member 51 of the filter unit 62 in that order before being directed to the air intake vent 12a. By passing through two first filter members 41 and two second filter members 51, foreign matter can be more reliably removed from the outside air.

The shapes of the first filter member 41 and the second filter member 51 provided in the filter device 34 may be the same as the shape of the first filter member 41 provided in the filter device 33.

The electric motor 1 may be equipped with any number of filter devices. As an example, the electric motor 1 shown in FIG. 11 is equipped with multiple filter devices 35 arranged circumferentially. In detail, the electric motor 1 is equipped with four filter devices 35, each of which has a partial ring-like outer shape when viewed in the positive direction of the Y axis. The four filter devices 35 are spaced apart circumferentially. The structure of each filter device 35 is similar to that of filter device 31, but the circumferential length differs from that of filter device 31. The structure of each filter device 35 is the same as that of filter device 31.

The shape of the filter device is not limited to the above example, and may be any shape that can remove foreign matter, such as an annular shape, a circular shape, or a polygonal shape. As an example, the electric motor 1 shown in Figure 12 is equipped with a filter device 36 that extends circumferentially around the rotation axis AX and has an annular shape with a polygonal outer edge that is partially missing. The structure of filter device 36 is similar to that of filter device 31, but the shape of the outer edge when viewed in the positive direction of the Y axis differs from that of filter device 31.

As another example, the electric motor 1 shown in Figure 13 is equipped with a filter device 37 having a ring shape extending circumferentially around the rotation axis AX. The structure of the filter device 37 is similar to that of the filter device 31. The filter device 37 differs from the filter device 31 in that its outer shape when viewed in the positive direction of the Y axis is a ring. The outer edge of the filter device 37 may be polygonal. In other words, the filter device 37 may be annular in shape with a polygonal outer edge.

The shapes of the first filter member 41 and the second filter member 51 are not limited to the above examples and may be any shape that can remove foreign matter. As an example, the filter device 38 shown in FIG. 14 includes a first filter member 41 formed by molding a first metal member into a shape in which the angle between the first front surface 42 and the first side surface 44 can be considered to be 90 degrees or greater. In the example shown in FIG. 14, the first filter member 41 is formed by molding the first metal member into an angle in which the angle between the first front surface 42 and the first side surface 44 can be considered to be 90 degrees. In the example shown in FIG. 14, the distance between two first side surfaces 44 connected to the same first rear surface 43 can be considered to be such that the length W41 downstream in the inflow direction is equal to the length W42 upstream in the inflow direction. The molding method for the first metal member is arbitrary.

As another example, the first front surface portion 42, the first rear surface portion 43, the second front surface portion 52, and the second rear surface portion 53 are not limited to being flat plate-like members, but may have the shape of a plate-like member with a curved surface. Furthermore, the shape of the main surface 44a of the first side surface portion 44 and the main surface 54a of the second side surface portion 54 may be a curved surface.

In the filter devices 32 and 34, the distance between the first filter member 41 and the second filter member 51 may be arbitrary. As an example, the first filter member 41 and the second filter member 51 may be disposed at a position where a portion of the first filter member 41 and a portion of the second filter member 51 abut each other.

The extension direction of the first front portion 42 and the first back portion 43 of the first filter member 41 is not limited to the above example. As an example, the first front portion 42 and the first back portion 43 may extend vertically and horizontally. In this case, the first front portion 42 and the first back portion 43 are positioned with a gap between them in the vertical or horizontal direction.

The structure of the electric motor 1 is not limited to the above example, and can be any open-type electric motor that takes in outside air to cool the inside. As one example, the electric motor 1 may be a frameless type electric motor that does not have a frame 11. As another example, the electric motor 1 is not limited to the inner rotor shown in the above embodiment, but may be an outer rotor.

The rotor core 15a may be formed with rotor ventilation passages, which are through-holes that open to both ends in the direction of extension of the rotation axis AX. By allowing outside air to flow through the rotor ventilation passages, the rotor core 15a can be cooled more efficiently. In this case, it is preferable that the air intake holes 12a be formed in positions facing the gap 20 and the rotor ventilation passages.

A stator ventilation passage may be formed in the stator core 16a. By allowing outside air to flow through the stator ventilation passage, the stator core 16a is cooled more efficiently. In this case, it is preferable that the air intake hole 12a be formed in a position facing the air gap 20 and the stator ventilation passage.

The method of attaching the filter devices 31-38 to the electric motor 1 is not limited to the above example. The filter devices 31-38 can be attached to the electric motor 1 by any method, such as adhesive bonding, fitting, or welding.

The on-board equipment to which the filter device is attached is not limited to electric motors. As an example, the power conversion device 2 shown in FIG. 15 includes a housing 3 that houses electronic components such as a converter circuit, an inverter circuit, and a reactor, and a filter device 39 that is attached to the housing 3 and blocks the air intake vent 3a formed in the housing 3. The filter device 39 has a rectangular outer shape when viewed in the negative Y-axis direction. The filter device 39 includes, for example, a first filter member 41 having an uneven shape extending in the Z-axis direction. In other words, the first filter member 41 has a shape in which protruding portions in the Y-axis direction and recessed portions in the Y-axis direction are alternately arranged. Air that flows into the housing 3 through the filter device 39 flows along the electronic components, such as the reactor, housed in the open section through which outside air flows in, cooling the electronic components before flowing out of the housing 3.

The shape of the first filtering member 41 included in the filtering device 35-39 may be the same as the shape of the first filtering member 41 included in the filtering device 33. The filtering device 35-39 may further include a second filtering member 51.
Various aspects of the present disclosure are summarized below as appendices.
(Appendix 1)
A filter device is attached to an on-board device of a railway vehicle that cools the interior with outside air taken in through an air intake hole, covering the air intake hole from the outside, removes foreign matter from the outside air flowing in, and guides the outside air from which the foreign matter has been removed to the air intake hole,
a plurality of first front surface portions, each of whose main surfaces intersects with the inflow direction of the outside air, and adjacent first front surface portions are positioned with a first gap between them;
a plurality of first back surface portions, each of whose main surfaces faces the first gap between two adjacent first front surface portions, and which are located downstream of the first front surface portions in the inflow direction and spaced apart from one another;
a first filtering member having a plurality of first side portions connecting the first rear surface portion to each of the two first front surfaces positioned on either side of the first gap to which the main surface of the first rear surface portion is directed;
a distance between the two first side surface portions connected to the same first rear surface portion such that the distance downstream in the inflow direction is greater than the distance upstream in the inflow direction;
The sum of the surface areas of the first side portions is greater than the sum of the surface areas of the first front portion and the first rear portion.
Filter device.
(Appendix 2)
Further provided is a second filter member located downstream of the first filter member in the inflow direction,
The second filter member is
a plurality of second front surface portions, each of whose main surfaces faces one of the first front surface portions different from the other, and adjacent second front surface portions are positioned with a second gap therebetween;
a plurality of second back surface portions, each of whose main surfaces faces a second gap between two adjacent second front surface portions, and which are located downstream of the second front surface portions in the inflow direction and spaced apart from one another;
a plurality of second side surfaces connecting the second rear surface portion to each of the two second front surfaces positioned across the second gap to which the main surface of the second rear surface portion faces;
2. The filter device of claim 1.
(Appendix 3)
a distance between two of the second side surface portions connected to the same second rear surface portion such that a length thereof on the downstream side in the inflow direction is equal to or greater than a length thereof on the upstream side in the inflow direction;
The sum of the surface areas of the second side portions is greater than the sum of the surface areas of the second front portion and the second rear portion.
3. The filter device of claim 2.
(Appendix 4)
The first filter member is formed of a mesh-like first metal member.
4. The filter device of claim 2 or 3.
(Appendix 5)
the second filter member is formed of a mesh-like second metal member,
The mesh size of the first filter member is larger than the mesh size of the second filter member,
The mesh spacing of the first filter member is wider than the mesh spacing of the second filter member.
5. The filter device of claim 4.
(Appendix 6)
a fixing frame having a protrusion on an inner surface, the first filtering member being attached to the inner surface by engaging with the protrusion, and the fixing frame being fixed to the in-vehicle device;
6. The filter device according to any one of claims 2 to 5.
(Appendix 7)
The first filter member and the second filter member are engaged with the protrusions, whereby the first filter member and the second filter member are attached to the inner surface of the fixing frame.
7. The filter device of claim 6.
(Appendix 8)
a plurality of filtration units each having the first filtration member and the second filtration member;
The plurality of filtration units are arranged in the inflow direction.
8. The filter device according to any one of claims 2 to 7.
(Appendix 9)
a shaft supported rotatably around a rotation axis;
a rotor located radially outside the shaft and rotating integrally with the shaft;
a stator facing the rotor with a gap in the radial direction;
a first bracket having an intake hole formed in an end surface intersecting the extension direction of the rotary shaft to allow outside air to flow in;
a second bracket facing the first bracket in the extension direction of the rotation shaft with the rotor and the stator interposed therebetween, the second bracket having an exhaust hole formed in an outer peripheral surface thereof through which the outside air flowing in from the intake hole flows out;
the filter device according to claim 1, which is attached to the first bracket in a state of covering the intake hole from the outside;
An electric motor comprising:
(Appendix 10)
a shaft supported rotatably around a rotation axis;
a rotor located radially outside the shaft and rotating integrally with the shaft;
a stator facing the rotor with a gap in the radial direction;
a first bracket having an intake hole formed in an end surface intersecting the extension direction of the rotary shaft to allow outside air to flow in;
a second bracket facing the first bracket in the extension direction of the rotation shaft with the rotor and the stator interposed therebetween, the second bracket having an exhaust hole formed in an outer peripheral surface thereof through which the outside air flowing in from the intake hole flows out;
The filter device according to any one of claims 2 to 8, which is attached to the first bracket in a state of covering the intake hole from the outside;
An electric motor comprising:
(Appendix 11)
The first filter member has a circular or partial circular shape extending in a circumferential direction around the rotation axis, an annular shape extending in the circumferential direction and having a polygonal outer edge, or an annular shape extending in the circumferential direction and having a polygonal outer edge with a portion missing.
11. The electric motor according to claim 9 or 10.
(Appendix 12)
The first front surface portion and the first rear surface portion of the first filter member extend in the radial direction and in the circumferential direction around the rotation axis, respectively.
12. The electric motor according to any one of appendices 9 to 11.
(Appendix 13)
a plurality of filter devices each having the first filtering member having a partial ring shape extending in a circumferential direction around the rotation axis, or an annular shape extending in the circumferential direction and having a polygonal outer edge with a portion missing,
The plurality of filter devices are arranged side by side in the circumferential direction.
11. The electric motor according to claim 9 or 10.
(Appendix 14)
The second filter member has a circular or partial circular shape extending in a circumferential direction around the rotation axis, an annular shape extending in the circumferential direction and having a polygonal outer edge, or an annular shape extending in the circumferential direction and having a polygonal outer edge with a portion missing.
11. The electric motor of claim 10.
(Appendix 15)
the second front surface portion and the second rear surface portion of the second filter member extend in the radial direction and in the circumferential direction around the rotation axis, respectively;
15. The electric motor of claim 10 or 14.
(Appendix 16)
a plurality of filter devices each having the first filter member having a partial ring shape extending in a circumferential direction around the rotation axis, or an annular shape extending in the circumferential direction with a polygonal outer edge and a missing portion, and a second filter member having a partial ring shape extending in a circumferential direction around the rotation axis, or an annular shape extending in the circumferential direction with a polygonal outer edge and a missing portion,
The plurality of filter devices are arranged side by side in the circumferential direction.
11. The electric motor of claim 10.

This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of the disclosure. Furthermore, the above-described embodiments are intended to illustrate the disclosure and do not limit the scope of the disclosure. In other words, the scope of the disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of equivalent disclosures are deemed to be within the scope of this disclosure.

REFERENCE SIGNS LIST 1 Electric motor, 2 Power conversion device, 3 Housing, 3a Intake hole, 11 Frame, 12 First bracket, 12a Intake hole, 13 Second bracket, 13a Exhaust hole, 14 Shaft, 15 Rotor, 15a Rotor core, 15b Rotor bar, 16 Stator, 16a Stator core, 16b Stator coil, 17, 18 Bearing, 19 Fan, 20 Air gap, 31, 32, 33, 34, 35, 36, 37, 38, 39 Filter device, 40 Fixing frame, 41 First filtering member, 42 First front surface, 42a, 43a, 44a, 52a, 53a, 54a Main surface, 42b, 43b, 44b, 52b, 53b, 54b Ventilation hole, 43 First rear surface, 44 First side surface, 45 First gap, 51: Second filtering member, 52: Second front surface portion, 53: Second rear surface portion, 54: Second side surface portion, 55: Second gap, 61, 62: Filtering unit, AX: Rotation axis, W11, W12, W21, W22, W31, W32, W41, W42: Length.

Claims (16)

A filter device is attached to an on-board device of a railway vehicle that cools the interior with outside air taken in through an air intake hole, covering the air intake hole from the outside, removes foreign matter from the outside air flowing in, and guides the outside air from which the foreign matter has been removed to the air intake hole,
a plurality of first front surface portions, each of whose main surfaces intersects with the inflow direction of the outside air, and adjacent first front surface portions are positioned with a first gap between them;
a plurality of first back surface portions, each of whose main surfaces faces the first gap between two adjacent first front surface portions, and which are located downstream of the first front surface portions in the inflow direction and spaced apart from one another;
a first filtering member having a plurality of first side portions connecting the first rear surface portion to each of the two first front surfaces positioned on either side of the first gap to which the main surface of the first rear surface portion is directed;
a distance between the two first side surface portions connected to the same first rear surface portion such that the distance downstream in the inflow direction is greater than the distance upstream in the inflow direction;
The sum of the surface areas of the first side portions is greater than the sum of the surface areas of the first front portion and the first rear portion.
Filter device. Further provided is a second filter member located downstream of the first filter member in the inflow direction,
The second filter member is
a plurality of second front surface portions, each of whose main surfaces faces one of the first front surface portions different from the other, and adjacent second front surface portions are positioned with a second gap therebetween;
a plurality of second back surface portions, each of whose main surfaces faces a second gap between two adjacent second front surface portions, and which are located downstream of the second front surface portions in the inflow direction and spaced apart from one another;
a plurality of second side surfaces connecting the second rear surface portion to each of the two second front surfaces positioned across the second gap to which the main surface of the second rear surface portion faces;
The filter device according to claim 1 . a distance between two of the second side surface portions connected to the same second rear surface portion such that a length thereof on the downstream side in the inflow direction is equal to or greater than a length thereof on the upstream side in the inflow direction;
The sum of the surface areas of the second side portions is greater than the sum of the surface areas of the second front portion and the second rear portion.
The filter device according to claim 2 . The first filter member is formed of a mesh-like first metal member.
4. The filter device according to claim 2 or 3. the second filter member is formed of a mesh-like second metal member,
The mesh size of the first filter member is larger than the mesh size of the second filter member,
The mesh spacing of the first filter member is wider than the mesh spacing of the second filter member.
5. The filter device according to claim 4. a fixing frame having a protrusion on an inner surface, the first filtering member being attached to the inner surface by engaging with the protrusion, and the fixing frame being fixed to the in-vehicle device;
4. The filter device according to claim 2 or 3 . The first filter member and the second filter member are engaged with the protrusions, whereby the first filter member and the second filter member are attached to the inner surface of the fixing frame.
7. The filter device according to claim 6. a plurality of filtration units each having the first filtration member and the second filtration member;
The plurality of filtration units are arranged in the inflow direction.
4. The filter device according to claim 2 or 3 . a shaft supported rotatably around a rotation axis;
a rotor located radially outside the shaft and rotating integrally with the shaft;
a stator facing the rotor with a gap in the radial direction;
a first bracket having an intake hole formed in an end surface intersecting the extension direction of the rotary shaft to allow outside air to flow in;
a second bracket facing the first bracket in the extension direction of the rotation shaft with the rotor and the stator interposed therebetween, the second bracket having an exhaust hole formed in an outer peripheral surface thereof through which the outside air flowing in from the intake hole flows out;
the filter device according to claim 1 being attached to the first bracket in a state of covering the intake hole from the outside;
An electric motor comprising: a shaft supported rotatably around a rotation axis;
a rotor located radially outside the shaft and rotating integrally with the shaft;
a stator facing the rotor with a gap in the radial direction;
a first bracket having an intake hole formed in an end surface intersecting the extension direction of the rotary shaft to allow outside air to flow in;
a second bracket facing the first bracket in the extension direction of the rotation shaft with the rotor and the stator interposed therebetween, the second bracket having an exhaust hole formed in an outer peripheral surface thereof through which the outside air flowing in from the intake hole flows out;
the filter device according to claim 2 or 3 , which is attached to the first bracket in a state of covering the intake hole from the outside;
An electric motor comprising: The first filter member has a circular or partial circular shape extending in a circumferential direction around the rotation axis, an annular shape extending in the circumferential direction and having a polygonal outer edge, or an annular shape extending in the circumferential direction and having a polygonal outer edge with a portion missing.
10. The electric motor according to claim 9 . The first front surface portion and the first rear surface portion of the first filter member extend in the radial direction and in the circumferential direction around the rotation axis, respectively.
10. The electric motor according to claim 9 . a plurality of filter devices each having the first filtering member having a partial ring shape extending in a circumferential direction around the rotation axis, or an annular shape extending in the circumferential direction and having a polygonal outer edge with a portion missing,
The plurality of filter devices are arranged side by side in the circumferential direction.
10. The electric motor according to claim 9 . The second filter member has a circular or partial circular shape extending in a circumferential direction around the rotation axis, an annular shape extending in the circumferential direction and having a polygonal outer edge, or an annular shape extending in the circumferential direction and having a polygonal outer edge with a portion missing.
11. The electric motor according to claim 10. the second front surface portion and the second rear surface portion of the second filter member extend in the radial direction and in the circumferential direction around the rotation axis, respectively;
The electric motor according to claim 10. a plurality of filter devices each having the first filter member having a partial ring shape extending in a circumferential direction around the rotation axis, or an annular shape extending in the circumferential direction with a polygonal outer edge and a missing portion, and a second filter member having a partial ring shape extending in a circumferential direction around the rotation axis, or an annular shape extending in the circumferential direction with a polygonal outer edge and a missing portion,
The plurality of filter devices are arranged side by side in the circumferential direction.
11. The electric motor according to claim 10.