FILTER UNIT AND ELECTRIC MOTOR

Abstract

A filter assembly (31) comprises a first filtration element (41) which has first front parts (42), first rear parts (43), and first side parts (44). The first front parts (42) each have a main surface (42a) that intersects an inflow direction of outside air. The first front parts (42) are arranged with first gaps (45) between them. The first rear parts (43) each have a main surface (43a) that faces the first gap (45) between two adjacent first front parts (42). The first rear parts (43) are arranged downstream of the first front parts (42) at intervals between them. The first side parts (44) connect the first front parts (42) and the first rear parts (43).A distance between two first side parts (44) connected to the same first rear part (43) has a downstream length in the inflow direction that is equal to or greater than a length upstream in the inflow direction, and a total surface area of ​​the first side parts (44) is greater than a total surface area of ​​the first front parts (42) and the first rear parts (43).

Description

Technical field

[0001] The present disclosure relates to a filter device and an electric motor. Technical background

[0002] Some in-vehicle equipment for rail vehicles cools an interior space, particularly electronic components located within that space that generate heat during operation, using outside air drawn in through an inlet opening. Such in-vehicle equipment includes a filter device located outside the inlet opening to prevent the electronic components from malfunctioning due to contact with dust, moisture, and other contaminants present in the outside air. Patent reference 1 discloses an example of such in-vehicle equipment.

[0003] The air compressor device for a rail vehicle disclosed in patent literature 1 draws in outside air, which has flowed through a filter section of a filter unit, as cooling air into the interior of a housing by rotating a cooling fan. The filter section has a concave-convex shape with repeated outwardly convex sections and inwardly concave sections relative to the housing. Citation list of patent literature

[0004] Patent literature 1: Unexamined Japanese patent application publication no. 2011-153534 Brief description of the invention: Technical problem

[0005] The filter section contained in the air compressor unit for a rail vehicle, disclosed in patent literature 1, has a concave-convex shape with a continuous V-shaped horizontal cross-section. The plate-shaped filter elements forming the V-shape are arranged along directions that intersect an inflow direction along which outside air flows in. After a prolonged period of use of the filter section, foreign substances can adhere to the edges of the ventilation openings of the plate-shaped filter elements, which are arranged along the directions that intersect the inflow direction, thereby clogging the ventilation openings.Such a blockage of the ventilation openings over time causes a reduction in the flow paths for air that has passed through the filter section, and thus leads to a rapid reduction in the flow rate of the filter section, resulting in a rapid reduction in the cooling capacity of the air compressor unit for a rail vehicle.

[0006] The present disclosure is made in view of the circumstances described above, and one objective of the present disclosure is to provide a filtering device comprising a filtering device and an electric motor which makes it possible to suppress a rapid reduction in a flow rate over time. Solution to the problem

[0007] To achieve the aforementioned objective, a filter device according to the present disclosure is a filter device to be attached to in-vehicle equipment for a rail vehicle, configured to cool an interior thereof with outside air drawn in through an inlet opening, such that the inlet opening is covered from the outside, and configured to remove foreign substances from the outside air flowing into the in-vehicle equipment and to direct the outside air free of foreign substances to the inlet opening, and comprises a first filtration element having a plurality of first front parts, a plurality of first rear parts, and a plurality of first side parts. Each of the plurality of first front parts has a main surface that intersects an inflow direction of the outside air.Each pair of adjacent first front parts of the plurality of first front parts is arranged with a first gap between them. Each of the plurality of first rear parts has a main surface facing the first gap between two adjacent first front parts of the plurality of first front parts. The plurality of first rear parts is arranged downstream of the plurality of first front parts in the inflow direction, with gaps between them. The plurality of first side parts connects each of the plurality of first rear parts to each pair of first front parts of the plurality of first front parts, which are arranged with the first gap, facing the main surface of the first rear part, between them.A distance between any two first side parts of the plurality of first side parts, connected to the same first rear part of the plurality of first rear parts, has a downstream length in the upstream direction that is equal to or greater than an upstream length in the upstream direction. The total surface area of ​​the plurality of first side parts is greater than the total surface area of ​​the plurality of first front parts and the plurality of first rear parts. Advantageous effects of the invention

[0008] The filter device according to the present disclosure comprises the first filtration element, which has the plurality of first front parts having main surfaces intersecting the inflow direction, the plurality of first rear parts having main surfaces facing the first gaps between the plurality of first front parts, and the plurality of first side parts, each connecting one of the plurality of first rear parts to the two first front parts of the plurality of first front parts arranged between them with the first gap to which the main surface of the first rear part faces.The distance between any two first side parts of the plurality of first side parts connected to the same first rear part of the plurality of first rear parts has a downstream length in the inflow direction that is equal to or greater than an upstream length in the inflow direction, and a total surface area of ​​the plurality of first side parts is greater than the total surface area of ​​the plurality of first front parts and the plurality of first rear parts. The configuration described above makes it less likely that foreign matter will clog the first side parts, thereby enabling the creation of a filter arrangement in which a rapid decrease in flow rate over time is suppressed. Brief description of drawings Fig. Figure 1 is a perspective view of an electric motor according to embodiment 1; Fig. Figure 2 is a cross-sectional view of the electric motor according to embodiment 1; Fig. Figure 3 is a cross-sectional view of the electric motor according to embodiment 1 along line III-III of Fig. 2; Fig. Figure 4 is a side view of the electric motor according to embodiment 1; Fig. Figure 5 is a cross-sectional view of a filter device according to embodiment 1 along line VV of Fig. 4; Fig. Figure 6 is a cross-sectional view of the filter device according to embodiment 1 along line VI-VI of Fig. 4; Fig. Figure 7 is a cross-sectional view of a filter device according to embodiment 2; Fig. Figure 8 is a cross-sectional view of the filter device according to embodiment 2; Fig. Figure 9 is a cross-sectional view of a first modified example of the filter device according to the embodiments; Fig. Figure 10 is a cross-sectional view of a second modified example of the filter device according to the embodiments; Fig. Figure 11 shows a side view of an electric motor, a third modified example of the filter device according to the embodiments; Fig. Figure 12 shows a side view of an electric motor, a fourth modified example of the filter device according to the embodiments; Fig. Figure 13 shows a side view of an electric motor, a fifth modified example of the filter device according to the embodiments; Fig. Figure 14 is a cross-sectional view of a sixth modified example of the filter device according to the embodiments; and Fig. Figure 15 shows a front view of a power conversion device, a seventh modified example of the filter device according to the embodiments. Description of embodiments

[0009] A filter device and an electric motor according to embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Identical or corresponding components in the drawings are designated with the same reference numerals. Design 1

[0010] A filter device according to embodiment 1, comprising a filter device and an electric motor, is described in detail below, using an electric motor, which is a type of in-vehicle equipment for a rail vehicle, as an example. Fig. 1 and Fig. The electric motor 1 shown in Figure 2 is an open electric motor for driving a rail vehicle. The electric motor 1 is mounted under the floor of the rail vehicle by means of a fastening element (not shown). The electric motor 1 cools its structural components by drawing in outside air and circulating it within the motor 1. To prevent the ingress of dust, moisture, and other foreign substances contained in the outside air into the electric motor 1, the electric motor 1 has a filter device 31.

[0011] In Fig. 1 and Fig. Figure 2 indicates that the Z-axis direction is vertical when the rail vehicle is in a horizontal position. The Y-axis direction indicates the width of the rail vehicle. The X-axis direction indicates the direction of travel of the rail vehicle. In other words, the rail vehicle travels in a positive X-axis direction or in a negative X-axis direction. The X-axis, Y-axis, and Z-axis are perpendicular to each other. The same applies to the following drawings.

[0012] The electric motor 1 has a shaft 14 which is mounted so that it can rotate about a rotational axis AX which is in Fig. 1 and Fig. Figure 2, represented by dash-dot lines, shows a rotor 15 arranged radially outside the shaft 14 in a radial direction of the shaft 14 and rotatable integrally with the shaft 14; a stator 16 located opposite the rotor 15 at a defined distance in the radial direction; bearings 17 and 18 supporting the shaft 14 to allow rotation; and a fan 19 attached to the shaft 14 and rotatable integrally with the shaft 14. The radial direction is a direction orthogonal to the axis of rotation AX.

[0013] The electric motor 1 further comprises a frame 11 which houses the rotor 15, the stator 16, the bearings 17 and 18 and the fan 19 with shaft 14 passing through it, a first holder 12 which has an end surface which intersects a direction of extension of the axis of rotation AX and which has inlet openings 12a, a second holder 13 which is arranged opposite the first holder 12 in the direction of extension of the axis of rotation AX with the rotor 15 and the stator 16 in between and has an outer circumferential surface which has outlet openings 13a, and the filter device 31 which is attached to the first holder 12.

[0014] In the electric motor 1 with the configuration described above, due to the rotation of the fan 19, the outside air flowing into the interior of the electric motor 1 through the inlet openings 12a of the first holder 12 flows through a gap 20 between the rotor 15 and the stator 16 and then flows outwards through the outlet openings 13a of the second holder 13 from the electric motor 1, as shown in Fig. 2 is indicated by the solid line. The structural components of the electric motor 1, specifically the rotor 15, the stator 16, and the bearings 17 and 18, are cooled by the outside air flow described above.

[0015] The individual components of the electric motor 1 are described in detail. The frame 11 is attached to the underside of the rail vehicle by means of the fastening element. The frame 11 has a cylindrical shape with openings at both ends. The openings of the frame 11 at both ends are closed by the first bracket 12 and the second bracket 13.

[0016] The first holder 12 is attached to one end of the frame 11, specifically to the end on the side of the negative Y-axis direction. As in Fig. 3 shown, which runs along line III-III of Fig. As shown in the cross-sectional view shown in Figure 2, the first holder 12 has inlet openings 12a to allow outside air to flow in. The inlet openings 12a are preferably located opposite the flow path of outside air within the electric motor 1, specifically opposite the gap 20.

[0017] As in Fig. 1 and Fig. As shown in Figure 2, the second holder 13 is arranged opposite the first holder 12, with the rotor 15 and stator 16 positioned between them, in the Y-axis direction. The second holder 13 is attached to the other end of the frame 11, specifically to the end on the side of the positive Y-axis direction. The outer circumferential surface of the second holder 13 has outlet openings 13a to allow outside air, which flows in through the inlet openings 12a, to escape.

[0018] The shaft 14 has one end that is closer to the second support 13 and is coupled to an axle of the rail vehicle via a coupling and a gear (not shown). The shaft 14 rotates to drive the rail vehicle.

[0019] The rotor 15 has a rotor core 15a which is attached to the shaft 14, and rotor bars 15b which are received in grooves formed in an outer circumferential surface of the rotor core 15a.

[0020] The stator 16 has a stator core 16a, which is attached to an inner circumferential surface of the frame 11, and stator coils 16b, which are received in slots formed in the stator core 16a. The stator core 16a is radially opposite the rotor core 15a at a defined distance between them.

[0021] Bearing 17 is held by the first bracket 12 and supports the shaft 14 in such a way that rotation is permitted. Bearing 18 is held by the second bracket 13 and supports the shaft 14 in such a way that rotation is permitted.

[0022] The fan 19 is mounted on the shaft 14 at a position between the stator 16 and the second support 13 and is integrally rotatable with the shaft 14. The rotation of the shaft 14 causes air from outside the electric motor 1 to flow into the interior of the electric motor 1 through the inlet openings 12a and causes the incoming outside air to flow outwards through the outlet openings 13a.

[0023] As in Fig. Figure 4, which shows the electric motor 1 in a view from the positive Y-axis direction, shows the filter device 31 attached to the first holder 12 to cover the inlet openings 12a of the first holder 12. In embodiment 1, the filter device 31 is attached to the first holder 12 by fastening it with fasteners.

[0024] The filter device 31 removes foreign substances from the incoming outside air and directs the freed outside air to the inlet openings 12a. As a result, the outside air, now freed from foreign substances by the filter device 31, flows through the inlet openings 12a into the interior of the electric motor 1. In embodiment 1, the positive Y-axis direction is an inflow direction of the outside air. The filter device 31 removes foreign substances from the outside air flowing in the direction of the positive Y-axis and directs the freed outside air to the inlet openings 12a, which are arranged relative to the filter device 31 on the side of the positive Y-axis direction.

[0025] The filter assembly 31 comprises a mounting frame 40, which is attached to the first holder 12, and a first filtration element 41, which is attached to the mounting frame 40 and suppresses the ingress of foreign substances in the ambient air into the electric motor 1. In embodiment 1, the mounting frame 40 and the first filtration element 41 have a semicircular shape that extends circumferentially around the axis of rotation AX.

[0026] As in Fig. 4 and Fig. 5 shown, where Fig. 5 one along the VV line from Fig. As shown in the cross-sectional view shown in Figure 4, the first filtration element 41 has a concave-convex shape extending radially perpendicular to the axis of rotation AX. In detail, the first filtration element 41, as shown in Figure 4, has a concave-convex shape extending radially perpendicular to the axis of rotation AX. Fig. Figure 5 shows a plurality of first front parts 42, each having main surfaces 42a that intersect the inflow direction of the outside air, i.e., the positive Y-axis direction. Two adjacent first front parts 42 are arranged with a first gap 45 between them. The first filtration element 41 has a plurality of first rear parts 43, each having main surfaces 43a facing the first gap 45 between the adjacent first front parts 42, and arranged downstream of the first front parts 42 in the inflow direction at intervals between them, as well as a plurality of first side parts 44, each connecting one of the first rear parts 43 to the two first front parts 42 that are arranged between them with the first gap 45, to which the main surface 43a of this first rear part 43 faces.

[0027] In embodiment 1, the first filtration element 41 has the plurality of first front parts 42 which have the main surfaces 42a perpendicular to the Y-axis direction, as well as the plurality of first rear parts 43 which have the main surfaces 43a perpendicular to the Y-axis direction.

[0028] As in Fig. As shown in Figure 4, the plurality of first front parts 42 are arranged along the circumferential direction around the axis of rotation AX with intervals between them. In embodiment 1, each of the first front parts 42 extends radially perpendicular to the axis of rotation AX and circumferentially.

[0029] The plurality of first rear sections 43 are arranged along the circumferential direction around the axis of rotation AX with intervals between them. In embodiment 1, each of the first rear sections 43 extends radially perpendicular to the axis of rotation AX and circumferentially.

[0030] Each of the first side parts 44 smoothly connects the first front part 42 and the first rear part 43. In embodiment 1, each of the first side parts 44 has a main section extending in the direction of rotation AX and in the radial direction, as well as end sections that connect the main section to the first front part 42 or the first rear part 43, respectively.

[0031] The distance between the two first side parts 44, which are connected by the same first rear part 43, has a length W11 downstream in the upstream direction that is equal to or greater than a length W12 upstream in the upstream direction. Specifically, the length W11, which is a length in the circumferential direction of the gap between any two first side parts 44 that are arranged circumferentially adjacent to each other downstream in the upstream direction, is equal to or greater than the length W12, which is a length in the circumferential direction of the gap between any two first side parts 44 that are arranged circumferentially adjacent to each other upstream in the upstream direction. In other words, an angle between a planar section of the main surface 42a of the first front part 42 and a planar section of the main surface 44a of the first side part 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. Thus, the first side parts 44 are arranged such that the main surfaces 44a are aligned along the inflow direction.

[0032] The total surface area of ​​the first side parts 44 is larger than the total surface area of ​​the first front parts 42 and the first rear parts 43. In detail, the total surface area of ​​the main surfaces 44a of the first side parts 44 is larger than the total surface area of ​​the main surfaces 42a of the first front parts 42 and the main surfaces 43a of the first rear parts 43.

[0033] The in Fig. The main surfaces 42a of the first front parts 42, the main surfaces 43a of the first rear parts 43, and the main surfaces 44a of the first side parts 44 shown in Figure 5 are each one of two main surfaces located closer upstream to the outside air passing through the filter assembly 31. For example, the main surfaces 42a of the first front parts 42 are surfaces of the first front parts 42 on the side of the negative Y-axis direction. Similarly, the main surfaces 43a of the first rear parts 43 are surfaces of the first rear parts 43 on the side of the negative Y-axis direction. The main surface 44a of the first side part 44, which is shown in Figure 5, is located on the side of the first side part 44. Fig. The surface 44a of the first side part 44, located at the right end, is on the side of the positive X-axis direction. Fig. 5 is located at the left end, which is a surface of this first side part 44 on the side of the negative X-axis direction.

[0034] In embodiment 1, the first filtration element 41 is formed by repeatedly folding a first metal element with a mesh structure into a U-shape, alternately changing the folding direction to form a bellows shape. The first metal element is, for example, stainless steel. Specifically, the first filtration element 41 is formed by repeatedly folding stainless steel mesh into a U-shape.

[0035] The filter assembly 31 is obtained by bending the entire first filtration element 41, which has been repeatedly folded into a U-shape, into an arc such that the fold lines forming the U-shape coincide with the radial direction, and by attaching the entire first filtration element 41 to an inner surface of the mounting frame 40. The mounting frame 40 has projections on its inner surface, and the fabric of the first filtration element 41 engages in these projections. As a result, the first filtration element 41 is attached to the mounting frame 40.

[0036] Since the first filtration element 41 is formed from the first metal element with the mesh structure, the first front parts 42, the first rear parts 43 and the first side parts 44 have ventilation openings 42b, 43b and 44b respectively, as shown in Fig. 6 shown, which is along line VI-VI of Fig. 4 is the recorded cross-sectional view.

[0037] As indicated by the solid arrows in Fig. As indicated in 6, the outside air passes through the filter device 31 via one of the ventilation openings 42b, 43b or 44b and flows as shown in Fig. 2 shown, enters the interior of the electric motor 1 through the inlet openings 12a, flows through the gap 20 and then flows out through the outlet openings 13a.

[0038] After the filter has been used for an extended period, foreign matter may clog the ventilation openings for the passage of outside air. In the filter assembly 31, the main surfaces 42a of the first front parts 42 and the main surfaces 43a of the first rear parts 43 are arranged orthogonally to the direction of inflow, and the first side parts 44 are arranged such that the main surfaces 44a are aligned along the direction of inflow. A large amount of outside air flows through the ventilation openings 42b in the main surfaces 42a of the first front parts 42 and the ventilation openings 43b in the main surfaces 43a of the first rear parts 43, which are arranged orthogonally to the direction of inflow of outside air.Therefore, after the filter device 31 has been used for a longer period of time, it is less likely that foreign substances will clog the ventilation openings 44b in the first side parts 44 with the main surfaces 44a aligned along the inflow direction, compared to the ventilation openings 42b in the first front parts 42 and the ventilation openings 43b in the first rear parts 43.

[0039] As described above, the filter device 31 according to embodiment 1 comprises the first filtration element 41, which has a plurality of first front parts 42, a plurality of first rear parts 43, and a plurality of first side parts 44, each connecting one of the first rear parts 43 to the two first front parts 42, which are arranged between them with the first gap 45, to which the main surface of this first rear part 43 faces. The distance between the two first side parts 44 connected to the same first rear part 43 has a downstream length in the inflow direction that is equal to or greater than a length upstream in the inflow direction, and the total surface area of ​​the first side parts 44 is greater than the total surface area of ​​the first front parts 42 and the first rear parts 43.

[0040] Since the distance between the two first side parts 44, which are connected to the same first rear part 43, has a downstream length in the inflow direction that is equal to or greater than a length upstream in the inflow direction, and since the total surface area of ​​the first side parts 44, where foreign matter is less likely to clog, is larger than the total surface area of ​​the first front parts 42 and the first rear parts 43, foreign matter is less likely to clog the filter device 31 compared to a filter with a concave-convex shape with a continuous V-shape. With this configuration, a filter device 31 can be obtained in which a rapid decrease in flow rate over time is suppressed. As a result, an electric motor 1 can be obtained in which a rapid decrease in cooling capacity over time is suppressed.

[0041] Since foreign matter, as described above, is less likely to clog the first side panels 44 and the rapid decrease in flow rate over time is suppressed, the period between the initial use of the filter assembly 31 and the time at which the filter assembly 31 needs to be cleaned to remove foreign matter is extended. This extends the maintenance cycle of the filter assembly 31 and thereby improves maintenance performance.

[0042] Due to the concave-convex shape formed by the first front parts 42, the first rear parts 43 and the first side parts 44, the surface area of ​​the first filtration element 41 is larger than that of a plate-shaped filtration element in a total area of ​​the ventilation openings, resulting in a large flow rate. Design 2

[0043] The configuration of the filter device is not limited to the example described above. In embodiment 2, a filter device comprising several filtration elements is described, with the focus being on the differences from embodiment 1. A Fig. The filter assembly 32 shown in Figure 7 has, in addition to the components of the filter assembly 31 according to embodiment 1, a second filtration element 51. The filter assembly 32 removes foreign substances from the incoming outside air by means of the first filtration element 41 and the second filtration element 51 and directs the outside air free of foreign substances to the inlet openings 12a. As in embodiment 1, the positive Y-axis direction is an inflow direction of the outside air.

[0044] Like the first filtration element 41, the second filtration element 51 has a concave-convex shape that extends radially perpendicular to the axis of rotation AX. Specifically, the second filtration element 51 has a plurality of second front parts 52, each with main surfaces 52a facing different first front parts 42. Two adjacent second front parts 52 are arranged with a second gap 55 between them.The second filtration element 51 has a plurality of second rear parts 53, each having main surfaces 53a facing the second gap 55 between the adjacent second front parts 52, and arranged downstream of the second front parts 52 in the inflow direction with intervals between them, as well as a plurality of second side parts 54, each connecting one of the second rear parts 53 to the two second front parts 52, which are arranged between them with the second gap 55, to which the main surface 53a of this second rear part 53 faces.

[0045] In embodiment 2, the second filtration element 51 has the plurality of second front parts 52, which have the main surfaces 52a perpendicular to the Y-axis direction, as well as the plurality of second rear parts 53, which have the main surfaces 53a perpendicular to the Y-axis direction.

[0046] The convex sections of the second filtration element 51 are arranged downstream of the convex sections of the first filtration element 41 in the inflow direction. The concave sections of the second filtration element 51 are arranged downstream of the concave sections of the first filtration element 41 in the inflow direction. Specifically, the main surfaces 52a of the second front sections 52 each face different first front sections 42, and the main surfaces 53a of the second rear sections 53 each face different first rear sections 43.

[0047] The plurality of second front parts 52 are arranged along the circumferential direction around the axis of rotation AX with intervals between them. In embodiment 2, each of the second front parts 52 extends radially perpendicular to the axis of rotation AX and circumferentially.

[0048] The plurality of second rear parts 53 are arranged along the circumferential direction around the axis of rotation AX with intervals between them. In embodiment 2, each of the second rear parts 53 extends radially perpendicular to the axis of rotation AX and circumferentially.

[0049] Each of the second side parts 54 smoothly connects the second front part 52 and the second rear part 53. In embodiment 2, each of the second side parts 54 has a main section extending in the direction of rotation AX and in the radial direction, as well as end sections that connect the main section to the second front part 52 or the second rear part 53, respectively.

[0050] The distance between the two second side parts 54, which are connected to the same second rear part 53, has a length W21 downstream in the upstream direction that is equal to or greater than a length W22 upstream in the upstream direction. Specifically, the length W21, which is a length in the circumferential direction of the gap between any two second side parts 54 that are arranged circumferentially adjacent to each other downstream in the upstream direction, is equal to or greater than the length W22, which is a length in the circumferential direction of the gap between any two second side parts 54 that are arranged circumferentially adjacent to each other upstream in the upstream direction. In other words, an angle between a planar section of the main surface 52a of the second front part 52 and a planar section of the main surface 54a of the second side part 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. Thus, the second side parts 54 are arranged such that the main surfaces 54a are aligned along the inflow direction.

[0051] The total surface area of ​​the second side parts 54 is larger than the total surface area of ​​the second front parts 52 and the second rear parts 53. In detail, the total surface area of ​​the main surfaces 54a of the second side parts 54 is larger than the total surface area of ​​the main surfaces 52a of the second front parts 52 and the main surfaces 53a of the second rear parts 53.

[0052] The main surfaces 52a of the second front parts 52, the main surfaces 53a of the second rear parts 53, and the main surfaces 54a of the second side parts 54 are each one of two main surfaces located closer upstream to the outside air passing through the filter device 32. For example, the main surfaces 52a of the second front parts 52 are surfaces of the second front parts 52 on the side of the negative Y-axis direction. Similarly, the main surfaces 53a of the second rear parts 53 are surfaces of the second rear parts 53 on the side of the negative Y-axis direction. The main surface 54a of the second side part 54, which is located in Fig. 7, located at the right end, is a surface of this second side part 54 on the side of the positive X-axis direction. The main surface 54a of the second side part 54, which is located in Fig. 7 is located at the left end, is a surface of this second side part 54 on the side of the negative X-axis direction.

[0053] In embodiment 2, the second filtration element 51 is formed by repeatedly folding a second metal element with a mesh structure into a U-shape, alternately changing the folding direction to form a bellows shape. The second metal element is made of the same material as the first metal element and is, for example, stainless steel. Specifically, the second filtration element 51 is formed by repeatedly folding stainless steel mesh into a U-shape.

[0054] The filter assembly 32 is obtained by bending the entire first filtration element 41 and the entire second filtration element 51, each repeatedly folded into a U-shape, into an arc such that the fold lines forming the U-shape coincide with the radial direction, and by attaching the entire first filtration element 41 and the entire second filtration element 51 to an inner surface of the mounting frame 40. The mounting frame 40 has projections on its inner surface, and the fabrics of the first filtration element 41 and the second filtration element 51 engage in these projections. As a result, the first filtration element 41 and the second filtration element 51 are attached to the mounting frame 40.

[0055] Since the second filtration element 51 is formed from the second metal element with the mesh structure, the second front parts 52, the second rear parts 53 and the second side parts 54 have ventilation openings 52b, 53b and 54b respectively, as shown in Fig. 8 shown.

[0056] As indicated by the solid arrows in Fig. As indicated in Figure 8, the outside air first passes through one of the ventilation openings 42b, 43b, or 44b and then through one of the ventilation openings 52b, 53b, or 54b to flow through the filter assembly 32. The outside air flowing through the filter assembly 32 enters the interior of the electric motor 1 through the inlet openings 12a, flows through the gap 20, and then flows outwards through the outlet openings 13a.

[0057] The size of the mesh openings of the first filtration element 41 is preferably larger than the size of the mesh openings of the second filtration element 51. Specifically, the size of the ventilation openings 42b, 43b and 44b is preferably larger than the size of the ventilation openings 52b, 53b and 54b.

[0058] The distances between the mesh openings of the first filtration element 41 are preferably greater than the distances between the mesh openings of the second filtration element 51. Specifically, the distances between adjacent ventilation openings 42b are greater than the distances between adjacent ventilation openings 52b. Similarly, the distances between adjacent ventilation openings 43b are greater than the distances between adjacent ventilation openings 53b. Similarly, the distances between adjacent ventilation openings 44b are greater than the distances between adjacent ventilation openings 54b.

[0059] Specifically, the filter device 32 is obtained by attaching the first filtration element 41, which is formed by repeatedly bending stainless steel mesh with large mesh openings and a large wire diameter into a U-shape, to the mounting frame 40, and the second filtration element 51, which is formed by repeatedly bending stainless steel mesh with small mesh openings and a small wire diameter into a U-shape.

[0060] With the configuration described above, the stiffness of the first filtration element 41 is higher than the stiffness of the second filtration element 51, and furthermore, the second filtration element 51 is a filter with mesh openings that are smaller than those of the first filtration element 41. The high stiffness of the first filtration element 41 reduces the likelihood of the filter assembly 32 being damaged by stones, sand, or other hard foreign matter. Using the second filtration element 51, which is a filter with mesh openings that are smaller than those of the first filtration element 41, makes it possible for the second filtration element 51 to remove small foreign matter contained in the ambient air that has passed through the first filtration element 41, such as iron dust, pollen, and fine dust (PM) 2.5.

[0061] After the filter has been used for an extended period, foreign matter may clog the ventilation openings for the passage of outside air. In the filter assembly 32, the main surfaces 52a of the second front parts 52 and the main surfaces 53a of the second rear parts 53 are arranged orthogonally to the direction of inflow, and the second side parts 54 are arranged such that the main surfaces 54a are aligned along the direction of inflow. A large amount of outside air flows through the ventilation openings 52b in the main surfaces 52a of the second front parts 52 and the ventilation openings 53b in the main surfaces 53a of the second rear parts 53, which are arranged orthogonally to the direction of inflow of outside air.Therefore, after the filter device 32 has been used for a longer period of time, it is less likely that foreign substances will clog the ventilation openings 54b in the second side parts 54 with the main surfaces 54a aligned along the inflow direction, compared to the ventilation openings 52b in the second front parts 52 and the ventilation openings 53b in the second rear parts 53.

[0062] As described above, the filter device 32 according to embodiment 2 has the first filtration element 41, which has the plurality of first front parts 42, the plurality of first rear parts 43 and the plurality of first side parts 44, each connecting one of the first rear parts 43 to the two first front parts 42, which are arranged between them with the first gap 45, to which the main surface of this first rear part faces, and the second filtration element 51, which has the plurality of second front parts 52, the plurality of second rear parts 53 and the plurality of second side parts 54, each connecting one of the second rear parts 53 to the two second front parts 52, which are arranged between them with the second gap 55, to which the main surface of this second rear part 53 faces.

[0063] The distance between the two first side parts 44, which are connected to the same first rear part 43, has a downstream length in the upstream direction that is equal to or greater than a length upstream in the upstream direction, and the total surface area of ​​the first side parts 44 is greater than the total surface area of ​​the first front parts 42 and the first rear parts 43. The distance between the two second side parts 54, which are connected to the same second rear part 53, has a downstream length in the upstream direction that is equal to or greater than a length upstream in the upstream direction, and the total surface area of ​​the second side parts 54 is greater than the total surface area of ​​the second front parts 52 and the second rear parts 53.

[0064] Since the distance between the two first side parts 44, which are connected to the same first rear part 43, and the distance between the two second side parts 54, which are connected to the same second rear part 53, each has a downstream length in the inflow direction that is equal to or greater than a length upstream in the inflow direction, and since the total surface area of ​​the first side parts 44, where foreign matter is less likely to clog, is greater than the total surface area of ​​the first front parts 42 and the first rear parts 43, and the total surface area of ​​the second side parts 54, where foreign matter is less likely to clog, is greater than the total surface area of ​​the second front parts 52 and the second rear parts 53, foreign matter is less likely to clog the filter device 32.compared to a filter with a concave-convex shape with a continuous V-shape. With this configuration, a filter device 32 can be obtained in which a rapid decrease in flow rate over time is suppressed. As a result, an electric motor 1 can be obtained in which a rapid decrease in cooling capacity over time is suppressed.

[0065] Since foreign matter, as described above, is less likely to clog the first side panels 44 and the second side panels 54, and the rapid decrease in flow rate over time is suppressed, the period between the initial use of the filter assembly 32 and the time at which the filter assembly 32 needs to be cleaned to remove foreign matter is extended. This extends the maintenance cycle of the filter assembly 32 and thereby improves maintenance performance.

[0066] With the first filtration element 41, which has a higher stiffness than the stiffness of the second filtration element 51, and the second filtration element 51, which is a filter with mesh openings that are smaller than those of the first filtration element 41, a filter device 32 is available which suppresses damage caused by stones, sand or other large foreign matter while suppressing the penetration of small foreign matter such as iron dust, pollen and PM2.5.

[0067] The configuration in which the convex sections of the second filtration element 51 are arranged downstream of the convex sections of the first filtration element 41 in the inflow direction, and the concave sections of the second filtration element 51 are arranged downstream of the concave sections of the first filtration element 41 in the inflow direction, suppresses a strong magnification of the width of the filter assembly 32 in the inflow direction, which comprises the first filtration element 41 and the second filtration element 51, compared to the filter assembly 31.

[0068] The embodiments described above are not to be interpreted as limiting the scope of protection of this disclosure. The filter device can have any structure and shape that makes it possible to suppress the ingress of foreign substances into the electric motor 1 and to suppress a rapid decrease in the flow rate over time.

[0069] For example, in a Fig. In the filter assembly 33 shown in Figure 9, the first filtration element 41 contained in the filter assembly 33 maintains a distance between the two first side parts 44, which are connected to the same first rear part 43. This rear part has a downstream length W31 in the inflow direction that is longer than the upstream length W32 in the inflow direction. The downstream length W31 in the inflow direction can be longer than the upstream length W32 in the inflow direction to such an extent that the two first side parts 44, which are connected to the same first front part 42, do not come into contact with each other. The filter assembly 33 can further comprise the second filtration element 51, which has a similar configuration to the first filtration element 41.

[0070] As another example, one in Fig. The filter device 34 shown in Figure 10 comprises a plurality of filtration units, each having a first filtration element 41 and a second filtration element 51. Specifically, the filter device 34 includes a filtration unit 61, which has the first filtration element 41 and the second filtration element 51, and a filtration unit 62, which has the first filtration element 41 and the second filtration element 51. The filtration units 61 and 62 are arranged along the inflow direction, i.e., along the positive Y-axis direction.

[0071] The first filtration element 41, which is contained in the filtration unit 62 arranged downstream in the inflow direction, preferably has mesh openings that are smaller than those of the second filtration element 51, which is contained in the filtration unit 61 arranged upstream in the inflow direction. Specifically, the ventilation openings 42b in the first front parts 42 of the first filtration element 41, which is contained in the filtration unit 62, are preferably smaller than the ventilation openings 52b in the second front parts 52 of the second filtration element 51, which is contained in the filtration unit 61.Additionally, the distances between adjacent ventilation openings 42b in the first front parts 42 of the first filtration element 41 contained in the filtration unit 62 are preferably smaller than the distances between adjacent ventilation openings 52b in the second front parts 52 of the second filtration element 51 contained in the filtration unit 61.

[0072] Accordingly, the ventilation openings 43b in the first rear sections 43 of the first filtration element 41 contained in the filtration unit 62 are preferably smaller than the ventilation openings 53b in the second rear sections 53 of the second filtration element 51 contained in the filtration unit 61. Additionally, the distances between adjacent ventilation openings 43b in the first rear sections 43 of the first filtration element 41 contained in the filtration unit 62 are preferably smaller than the distances between adjacent ventilation openings 53b in the second rear sections 53 of the second filtration element 51 contained in the filtration unit 61.

[0073] In the filter unit 34, the outside air is guided in this sequence through the first filtration element 41 and the second filtration element 51, which are contained in the filtration unit 61, and through the first filtration element 41 and the second filtration element 51, which are contained in the filtration unit 62, to the inlet openings 12a. The configuration of flowing through two first filtration elements 41 and two second filtration elements 51 enables a more reliable removal of foreign substances from the outside air.

[0074] The first filtration elements 41 and the second filtration elements 51 contained in the filter assembly 34 can have a shape that matches the shape of the first filtration element 41 contained in the filter assembly 33.

[0075] The number of filter devices included in electric motor 1 can be freely selected. For example, the one in Fig. Figure 11 shows an electric motor 1 with a plurality of filter devices 35 arranged along its circumference. Specifically, the electric motor 1 has four filter devices 35, each with a semicircular contour when viewed in the positive Y-axis direction. The four filter devices 35 are spaced apart along the circumference. Each of the filter devices 35 has a structure similar to filter device 31 but differs from filter device 31 in its length along the circumference. The filter devices 35 have the same structure.

[0076] The shape of the filter device is not limited to the examples described above and can be any shape that allows for the removal of foreign substances, such as a ring-shaped, circular, or polygonal shape. As an example, the one in Fig. Figure 12 shows an electric motor 1 with a filter device 36 that extends circumferentially around the axis of rotation AX and has a partially missing annular shape with a polygonal outer edge. The filter device 36 has a similar structure to the filter device 31, but differs from the filter device 31 in the shape of the outer edge when viewed in the positive Y-axis direction.

[0077] As another example, the one in Fig. Figure 13 shows an electric motor 1 and a filter device 37 that has a circular shape extending circumferentially around the axis of rotation AX. The filter device 37 has a similar structure to the filter device 31. The filter device 37 differs from the filter device 31 in that, when viewed in the positive Y-axis direction, it has a circular contour. The filter device 37 can have a polygonal outer edge. That is, the filter device 37 can have a ring-shaped form with a polygonal outer edge.

[0078] The shape of the first filtration element 41 and the second filtration element 51 is not limited to the examples described above and can be any shape that allows for the removal of foreign substances. For example, one in Fig. In the filter device 38 shown in 14, the first filtration element 41 is formed from the first metal element, which is shaped such that the angle between the first front part 42 and the first side part 44 can be considered to be equal to or greater than 90 degrees. In the example of Fig. 14 The first filtration element 41 is formed by shaping the first metal element such that angles are formed where the angle between the first front part 42 and the first side part 44 can be considered to be equal to 90 degrees. In the example of Fig. 14 The distance between the two first side parts 44, which are connected to the same first rear part 43, has a length W41 downstream in the inflow direction, which can be considered to be equal to a length W42 upstream in the inflow direction. The first metal element can be shaped in any way.

[0079] As a further example, the first front parts 42, the first rear parts 43, the second front parts 52, and the second rear parts 53 are not limited to flat plate elements and can have a form of plate elements with curved surfaces. Furthermore, the main surfaces 44a of the first side parts 44 and the main surfaces 54a of the second side parts 54 can be curved surfaces.

[0080] In filter devices 32 and 34, the distance between the first filtration element 41 and the second filtration element 51 can be freely selected. For example, the first filtration element 41 and the second filtration element 51 can be arranged in positions where part of the first filtration element 41 and part of the second filtration element 51 are in contact with each other.

[0081] The directions in which the first front parts 42 and the first rear parts 43 of the first filtration element 41 extend are not limited to the examples described above. For example, the first front parts 42 and the first rear parts 43 can extend in a vertical direction and in a horizontal direction. In this case, the first front parts 42 and the first rear parts 43 are arranged along the vertical direction or the horizontal direction with gaps between them.

[0082] The structure of the electric motor 1 is not limited to the examples described above, and the electric motor 1 can be any open electric motor that draws in outside air to cool an interior space. For example, the electric motor 1 can be a frameless electric motor without the frame 11. As another example, the electric motor 1 is not limited to an internal rotor, as in the embodiments described above, and can be an external rotor.

[0083] The rotor core 15a can have a rotor ventilation path, which is a through-hole open at both ends with respect to the direction of rotation AX. The flow of outside air through the rotor ventilation path leads to more efficient cooling of the rotor core 15a. In this case, the inlet openings 12a are preferably formed at positions opposite the gap 20 and the rotor ventilation path.

[0084] The stator core 16a can have a stator ventilation path. The flow of outside air through the stator ventilation path leads to more efficient cooling of the stator core 16a. In this case, the inlet openings 12a are preferably formed at positions opposite the gap 20 and the stator ventilation path.

[0085] The method of attaching the filter devices 31-38 to the electric motor 1 is not limited to the examples described above. The filter devices 31-38 can be attached to the electric motor 1 in any way, such as by gluing, fitting, or welding.

[0086] The vehicle's internal equipment to which the filter unit is attached is not limited to an electric motor. For example, one in Fig.Figure 15 shows a power conversion device 2 comprising a housing 3 containing electronic components such as a converter circuit, an inverter circuit, and an inductor, as well as a filter device 39 attached to the housing 3 to close an inlet opening 3a of the housing 3. The filter device 39 has a rectangular contour when viewed in the negative Y-axis direction. The filter device 39 includes the first filtration element 41, which has a concave-convex shape extending in the Z-axis direction. In other words, the first filtration element 41 has a shape in which sections projecting in the Y-axis direction and sections recessed in the Y-axis direction are arranged alternately.The air that has flowed into the interior of the housing 3 through the filter device 39 flows along the electronic components, for example a coil, which are housed in an open section into which the outside air flows, cools the electronic components and then flows outwards from the housing 3.

[0087] The first filtration element 41 contained in the filter devices 35-39 can have a shape that matches the shape of the first filtration element 41 contained in the filter device 33. The filter devices 35-39 can further comprise the second filtration element 51.

[0088] For illustrative purposes, some exemplary embodiments have been described above. Although the foregoing description presents specific embodiments, those skilled in the art will recognize that changes in form and detail can be made without departing from the broader spirit and scope of the invention. Accordingly, the description and the drawings are to be regarded as explanatory and not as limiting. This detailed description is therefore not to be understood in a limiting sense, and the scope of protection of the invention is determined exclusively by the appended claims, together with the full scope of the equivalents to which those claims refer. Reference symbol list 1 electric motor 2 Power conversion unit 3 cases 3a Entrance opening 11 frames 12 First owner 12a Entrance 13 Second Holder 13a Outlet opening 14 wave 15 Rotor 15a Rotor core 15b Rotor bar 16 Stator 16a Stator core 16b Stator coil 17, 18 camps 19 fans 20 gaps 31, 32, 33, 34, 35, 36, 37, 38, 39 Filter unit 40 mounting frames 41 First filtration element 42 First front part 42a, main area 43a, 44a, 52a, 53a, 54a 42b, 43b, 44b, 52b, 53b, 54b Ventilation opening 43 First buttocks 44 First side panel 45 First gap 51 Second filtration element 52 Second front part 53 Second buttocks 54 Second side panel 55 Second gap 61, 62 Filtration unit AX Rotation axis W11, W12, W21, W22, W31, W32, W41, W42 length

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