Inverter unit and gasket for inverter unit

Abstract

The inside and the outside of an inverter unit of a power conversion device according to the present embodiment are partitioned by a partition plate. The partition plate is provided with a round hole, and a cylindrical capacitor case is threaded through the round hole. A gap between the edge of the round hole in the partition plate and the capacitor case threaded through the round hole is filled by a gasket. The gasket is formed from a base and a membrane. The base and the membrane are of a single piece. The base has a circular shape and the edges thereof are pinched from the front and back when mounted in the round hole. The membrane extends from the base mounted in the round hole toward the center of the round hole and adheres to the circumferential surface of the capacitor case threaded through the round hole.

Description

Inverter unit and inverter unit packing

[0001] The present disclosure relates to an inverter unit for a power conversion device and a packing for the inverter unit.

[0002] The inverter unit of a power conversion device includes a capacitor. Generally, the case of the capacitor has a cylindrical shape. Patent Document 1 discloses an example of an inverter unit including a cylindrical capacitor.

[0003] The inverter unit disclosed in Patent Document 1 includes a partition plate (housing base) that separates the interior into a main body portion in which multiple switching elements are arranged and an air channel portion through which cooling air passes. A through-hole is formed in the housing base through which a capacitor cover passes. The capacitor cover has a cylindrical shape with a bottom and is made of an elastic silicone rubber material. The capacitor is housed in the capacitor cover while being fitted into a capacitor band and an annular metal plate. The capacitor cover has a flange. The flange is fixed to the main body portion of the housing base together with the capacitor band and the annular metal plate by a fixing screw, thereby fixing the capacitor and the capacitor cover to the housing base while passing through the through-hole.

[0004] In the prior art disclosed in Patent Document 1, the capacitor is bound around the periphery of the case by a capacitor band, and in this state, it is fixed to the housing base together with the annular metal plate and the flange of the capacitor cover. With this type of fixing method, the gap of the through-hole formed in the housing base is sealed by the flange of the capacitor cover, which may prevent dust from entering the main body from the air channel. However, on the other hand, the constraint of the case by the capacitor band and the annular metal plate generates stress in the case when the capacitor thermally expands when current is applied. This stress may lead to damage to the case.

[0005] Japanese Patent Publication No. 2012-227252

[0006] The present disclosure has been made in view of the above-mentioned problems, and one object of the present disclosure is to provide a technology that can seal the gap of a partition plate that separates the inside of an inverter unit without causing stress in the case when a case that houses a capacitor penetrates through the partition plate that separates the inside of the inverter unit.

[0007] An inverter unit of a power conversion device according to one embodiment of the present disclosure includes a capacitor housed in a cylindrical capacitor case, a partition plate separating the interior and exterior of the inverter unit and having a circular hole through which the capacitor case passes, a packing that fills a gap between the edge of the circular hole in the partition plate and the capacitor case that passes through the circular hole, and an annular base that sandwiches the edge of the packing from the front and back sides when the packing is installed in the circular hole, and a membrane that extends from the base toward the center of the circular hole and is in close contact with the periphery of the capacitor case.

[0008] The inverter unit may further include a stud provided on the bottom of the capacitor case and a support plate to which the stud is fixed. The inverter unit may also include one or more switching elements and a laminated conductor that connects the one or more switching elements and the capacitor terminals in the same plane.

[0009] An inverter unit packing according to one embodiment of the present disclosure is a packing that fills a gap between the edge of a circular hole in a partition plate provided within an inverter unit and a cylindrical capacitor case that passes through the circular hole. The inverter unit packing includes a base that sandwiches the edge of the circular hole from the front and back when the packing is attached to the circular hole, and a membrane that is integrated with the base and that, when attached to the circular hole in the base, adheres tightly to the peripheral surface of the capacitor case that passes through the circular hole.

[0010] In the inverter unit packing, the base may be an endless band-like body having a circular ring shape, and the membrane may be provided inside the ring of the base. Also, in the inverter unit packing, the base may be a band-like body made of a flexible material.

[0011] In the inverter unit described above, the gap between the capacitor case and the circular hole in the partition plate is sealed with a packing. The flexible membrane of the packing can maintain close contact with the periphery of the capacitor case even when the capacitor case thermally expands, preventing dust from entering the inverter unit from the outside. Furthermore, bending of the membrane in response to the thermal expansion of the capacitor case also prevents stress from being generated in the capacitor case.

[0012] The inverter unit packing described above can be attached to the round hole in the partition plate to seal the gap between the capacitor case and the round hole in the partition plate. Because the membrane is flexible, it can remain in close contact with the periphery of the capacitor case even when the capacitor case thermally expands, preventing dust from entering the inverter unit from the outside. Furthermore, bending of the membrane in response to the thermal expansion of the capacitor case also prevents stress from being generated in the capacitor case.

[0013] 1 is a perspective view of an inverter unit according to an embodiment of the present disclosure; FIG. 1 is a perspective view of the inverter unit shown in FIG. 1 with a cover and a laminated bus bar removed; FIG. 2 is a rear view of the inverter unit shown in FIG. 1; FIG. 3 is a cross-sectional view taken along line A-A of the inverter unit shown in FIG. 4, which is a side view of the inverter unit shown in FIG. 1; FIG. 4 is a detailed view of portion C of the inverter unit shown in FIG. 5; FIG. 5 is a detailed view of portion B of the inverter unit shown in FIG. 4; FIG. 6 is a diagram showing a state in which an inverter unit packing according to an embodiment of the present disclosure is attached to an inverter unit; FIG. 7 is a cross-sectional view showing an example of a specific shape of the inverter unit packing according to an embodiment of the present disclosure; FIG. 8 is a cross-sectional view showing the inverter unit packing shown in FIG. 9 attached to a round hole in a partition plate; FIG. 9 is a cross-sectional view showing a state in which the inverter unit packing shown in FIG. 9 seals the gap between the round hole in the partition plate and the capacitor case; FIG. 10 is a cross-sectional view showing another example of a specific shape of the inverter unit packing according to an embodiment of the present disclosure; FIG. 11 is a cross-sectional view showing the inverter unit packing shown in FIG. 12 attached to a round hole in a partition plate.

[0014] Hereinafter, an inverter unit and a packing used therein according to an embodiment of the present disclosure will be described with reference to the drawings.

[0015] 1. Inverter Unit Fig. 1 is a perspective view of the inverter unit according to this embodiment. The inverter unit 10 houses a plurality of capacitor cases 40 inside a housing 11. The capacitor cases 40 are cylindrical aluminum cases that house the capacitor bodies inside.

[0016] The interior of the inverter unit 10 is divided into a circuit chamber 101 and an air tunnel chamber 102 by a partition plate 30. The circuit chamber 101 is the space from the partition plate 30 to the cover 14. To prevent dust from entering from the outside, the circuit chamber 101 is sealed with a lid (not shown). Although hidden by the cover 14 and not shown in FIG. 1 , the circuit chamber 101 contains switching elements and a board unit, which are the main body of the inverter unit 10. Capacitor terminals 42 and 43 are also located in the circuit chamber 101. The capacitor terminals 42 and 43 are connected to the capacitor terminals 42 and 43 at the same potential by a laminated bus bar 22, which is a laminated conductor, and are also connected to one or more switching elements in the same plane.

[0017] The air tunnel chamber 102 is a space that is connected to the outside. The air tunnel chamber 102 can be considered to be outside the inverter unit 10, and the circuit chamber 101 can be considered to be inside the inverter unit 10, with the partition plate 30 as the boundary. Heat dissipation fins (not shown in Fig. 1) are arranged in the air tunnel chamber 102. The heat dissipation fins are installed to dissipate heat generated by the switching elements to the outside.

[0018] 2 is a perspective view of the inverter unit 10 with the cover 14 and laminated bus bar 22 shown in FIG. 1 removed. A plurality of switching elements 23, composed of semiconductor elements such as IGBTs, are arranged side by side on a floor 33 connected to the partition plate 30 by a step 32. The capacitor case 40 is arranged so that terminals 42, 43 provided on its top surface are positioned substantially flush with the switching elements 23. The circuit chamber 101 has two floors 33, 34, including the floor 33 on which the switching elements 23 are arranged. The circuit board unit 24 is installed on the upper floor 34.

[0019] The capacitor cases 40 are arranged in two rows. Each capacitor case 40 penetrates the partition plate 30. The partition plate 30 is a panel made of metal or hard resin. A round hole 31 is formed in the partition plate 30 to allow the capacitor case 40 to pass through. The space between the round hole 31 and the capacitor case 40 is sealed, and the structure for this sealing will be described in detail later. Studs not shown in FIG. 1 are provided on the bottom surface of the capacitor case 40. The studs are fixed to a support plate 50 provided in the wind tunnel chamber 102. The partition plate 30 and support plate 50 are fixed by a frame 12.

[0020] The above is an outline of the configuration of the inverter unit 10. The detailed configuration of the inverter unit 10 is shown in a rear view, a side view, and a cross-sectional view.

[0021] 3 is a rear view of the inverter unit 10. As shown in the rear view, a frame 13 is provided at the rear of the frame 12 provided at the entrance of the air tunnel chamber 102. This frame 13 is located near the center of the air tunnel chamber 102. The support plate 50 is fixed to these two frames 12, 13 on both sides. As described above, the studs 41 of the capacitor case 40 are fixed to the support plate 50. In addition, heat dissipation fins 21 are provided in the space behind the frame 13 in the air tunnel chamber 102.

[0022] FIG. 4 is a side view of the inverter unit 10 on the circuit chamber 101 side. The cover 14, board unit 24, floor 34, and laminated bus bar 22 shown in FIG. 1 have been removed in this side view. A step 32 connects the partition plate 30, through which the capacitor case 40 passes, to the floor 33 on which the switching elements 23 are arranged. Heat dissipation fins 21 (see FIG. 3) are attached to the back side of the floor 33, specifically, the back side of the switching elements 23. Multiple exhaust fans 15 are attached to the front of the inverter unit 10 (the right side in FIG. 4). The exhaust fans 15 exhaust high-temperature air heated by heat dissipation from the heat dissipation fins 21 in the air channel chamber 102 to the outside.

[0023] Fig. 5 is a cross-sectional view taken along line AA of the inverter unit 10 shown in Fig. 4. As shown in the cross-sectional view, the capacitor case 40 penetrates the partition plate 30, and both ends of the capacitor case 40 are sandwiched between the support plate 50 and the laminated bus bar 22.

[0024] 6 is a detailed view of portion C of the inverter unit 10 shown in FIG. 5. As shown in the detailed view of portion C, the bottom surface of the capacitor case 40 abuts against the support plate 50. Studs 41 provided on the bottom surface of the capacitor case 40 penetrate the support plate 50 and are fastened to bolts 51. The top surface of the capacitor case 40 abuts against the laminate bus bar 22. Terminals 42, 43 provided on the top surface of the capacitor case 40 are fixed to the laminate bus bar 22. As a result, both ends of the capacitor case 40 are restrained and positioned by the laminate bus bar 22 and the support plate 50. Meanwhile, a gap is provided between the capacitor case 40 and the partition plate 30, and the partition plate 30 does not directly restrain the capacitor case 40.

[0025] 7 is a detailed view of portion B of the inverter unit 10 shown in FIG. 4. As shown in the detailed view of portion B, a circular hole 31 is formed in the partition plate 30. A capacitor case 40 passes through the circular hole 31. The diameter of the capacitor case 40 used in the inverter unit 10 is always smaller than the diameter of the circular hole 31. Therefore, a gap is always formed between the peripheral surface 44 of the capacitor case 40 and the edge 31a of the circular hole 31. To prevent dust from entering through this gap, the inverter unit 10 is provided with a packing, which will be described below.

[0026] 2. Inverter Unit Gasket Figure 8 is a diagram showing the state in which the inverter unit gasket according to this embodiment is attached to the inverter unit 10. In the example shown in Figure 8, four round holes 31 are formed in the partition plate 30. No inverter unit gasket is attached to the round hole 31 in the upper right. When a capacitor case 40 is placed in a round hole 31 to which no inverter unit gasket is attached, a gap is formed between the peripheral surface 44 of the capacitor case 40 and the edge 31a of the round hole 31, as shown in the lower right.

[0027] An inverter unit packing 60 is attached to the upper left circular hole 31. The inverter unit packing 60 is arranged in a continuous ring shape along the edge 31a of the circular hole 31. When the capacitor case 40 is housed in the circular hole 31 to which the inverter unit packing 60 is attached, the gap between the peripheral surface 44 of the capacitor case 40 and the edge 31a of the circular hole 31 is filled with the inverter unit packing 60, as shown in the lower left. The inverter unit packing 60 is made of a material that has insulating properties, heat resistance, weather resistance, flame retardancy, and flexibility, such as ethylene propylene rubber (EPDM rubber) or chloroprene rubber (CR rubber).

[0028] FIG. 9 is a cross-sectional view showing an example of a specific shape of inverter unit packing 60. Inverter unit packing 60 includes a base 61 and a membrane 62. Base 61 is an endless band-like body in a circular ring shape. Membrane 62 is provided on the inside of the ring of base 61. Membrane 62 and base 61 are integrally molded. A groove 63 is formed on the outside of the ring of base 61. In the example shown in FIG. 9, membrane 62 is provided on base 61 so that membrane 62 and groove 63 are located on the same plane.

[0029] 10 is a cross-sectional view of the inverter unit packing 60 fitted into the circular hole 31 of the partition plate 30. When the inverter unit packing 60 is fitted into the circular hole 31, the edge 31a of the circular hole 31 is inserted into the groove 63 of the base 61. The base 61 is manufactured so that the width of the groove 63 is smaller than the thickness of the partition plate 30. Therefore, the edge 31a of the circular hole 31 fitted into the groove 63 of the base 61 is sandwiched by the base 61 from both the front and back sides. The base 61 is also manufactured to a size such that the edge 31a of the circular hole 31 abuts against the back of the groove 63. When the inverter unit packing 60 is fitted into the circular hole 31, the membrane 62 extends from the base 61 toward the center of the circular hole 31.

[0030] 11 is a cross-sectional view showing how the gap between the round hole 31 in the partition plate 30 and the capacitor case 40 is sealed by the inverter unit packing 60. The round hole 31 in the inverter unit packing 60 is fabricated so that the inner diameter of the membrane 62 is smaller than the outer diameter of the capacitor case 40. Therefore, when the capacitor case 40 is inserted into the round hole 31 fitted with the inverter unit packing 60, the membrane 62 extending from the base 61 toward the center of the round hole 31 comes into close contact with the peripheral surface 44 of the capacitor case 40.

[0031] 11 , the membrane 62 adheres closely to the peripheral surface 44 of the capacitor case 40, thereby sealing the gap between the capacitor case 40 and the circular hole 31 in the partition plate 30. Because the membrane 62 is flexible, it remains in close contact with the peripheral surface 44 of the capacitor case 40 even when the capacitor case 40 thermally expands when current is applied. This prevents dust from entering the circuit chamber 101 (inside) from the air tunnel chamber 102 (outside). Furthermore, bending of the membrane 62 in response to the thermal expansion of the capacitor case 40 prevents stress from occurring in the capacitor case 40, thereby reducing the risk of damage to the capacitor case 40.

[0032] 3. Modifications Instead of the inverter unit packing 60, an inverter unit packing 70 having the shape shown in FIG. 12 may be used. The inverter unit packing 70 includes an integrally molded base 71 and membrane 72. In the inverter unit packing 70, the upper surface of the base 71 and the upper surface of the membrane 72 are connected flatly. In other words, the inverter unit packing 70 has a flat upper surface without any steps. The groove 73 in the base 71 is formed on a plane offset from the plane on which the membrane 72 is located.

[0033] 13 is a cross-sectional view of the inverter unit packing 70 fitted into the circular hole 31 of the partition plate 30. The edge 31a of the circular hole 31 is inserted into the groove 73 of the base 71, so that the edge 31a of the circular hole 31 is sandwiched from both sides by the base 71. When the inverter unit packing 70 is fitted into the circular hole 31, the membrane 72 extends from the base 71 towards the center of the circular hole 31.

[0034] While the inverter unit packing used in the above embodiment is a circular, endless band, it is also possible to use a band-shaped inverter unit packing with ends made of a flexible material. For example, an arc-shaped or linear inverter unit packing having the cross-sectional shape shown in FIG. 9 or the cross-sectional shape shown in FIG. 12 can be used. If the band is made of a flexible material, it can be bent along the circular hole 31 and fitted into the edge 31a of the circular hole 31. Furthermore, by cutting the ends appropriately to adjust the length, it can be used for circular holes 31 of various sizes.

[0035] REFERENCE SIGNS LIST 10 inverter unit 22 laminated bus bar (laminated conductor) 23 switching element 30 partition plate 31 round hole 31a edge 40 capacitor case 41 stud 42, 43 terminal 50 support plate 60, 70 inverter unit packing 61, 71 base 62, 72 membrane 63, 73 groove 101 circuit chamber 102 wind tunnel chamber

Claims

1. An inverter unit of a power conversion device, comprising: a capacitor housed in a cylindrical capacitor case; a partition plate that partitions the inside and outside of the inverter unit and is provided with a round hole through which the capacitor case penetrates; and a packing that fills a gap between an edge of the round hole of the partition plate and the capacitor case in a state of penetrating the round hole, wherein the packing includes: an annular base that sandwiches the edge from the front side and the back side when mounted in the round hole; and a membrane that extends from the base in a direction of the center of the round hole and is in close contact with a circumferential surface of the capacitor case. An inverter unit characterized by the above.

2. The inverter unit according to claim 1, further comprising: a stud provided at a bottom of the capacitor case; and a support plate to which the stud is fixed. An inverter unit characterized by the above.

3. The inverter unit according to claim 1, further comprising: one or more switching elements; and a laminated conductor that connects the one or more switching elements and a terminal of the capacitor in the same plane. An inverter unit characterized by the above.

4. A packing for an inverter unit that fills a gap between an edge of a round hole of a partition plate provided in the inverter unit and a cylindrical capacitor case in a state of penetrating the round hole, wherein the packing includes: a base that sandwiches the edge from the front side and the back side when mounted in the round hole; and a membrane that is integrated with the base and is in close contact with a circumferential surface of the capacitor case in a state of penetrating the round hole when the base is mounted in the round hole. A packing for an inverter unit characterized by the above.

5. The packing for an inverter unit according to claim 4, wherein the base is an annular endless belt-like body, and the membrane is provided inside the annulus of the base. A packing for an inverter unit characterized by the above.

6. The packing for an inverter unit according to claim 4, wherein the base is a belt-like body formed of a flexible material. A packing for an inverter unit characterized by the above.

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