Enclosure for electric apparatus

Abstract

To provide a technique capable of surely conducting a housing and a cover in an enclosure in which a liquid-state gasket is used for sealing the housing and the cover.SOLUTION: An enclosure comprises: a housing and a cover which have conductivity; and a gasket which has non-conductivity. The housing includes an opening, and a first seating face is provided around the opening. The cover closes the opening of the housing. The gasket is disposed between the first seating face and the cover. The gasket is a liquid-state gasket which has flowability in the beginning but is hardened after coating. A second seating face, a positioning pin protruding from the second seating face and a groove separating the second seating face from the first seating face are provided in the housing. The cover includes a tab extending from a cover main body along with the second seating face. A positioning hole which is fitted to the positioning pin is provided in the tab. The tab is in contact with the second seating face, and the cover and the housing are conducted via the tab.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The technology disclosed in this specification relates to the housing of an electrical device.

Background Art

[0002] The housing of the electrical device has an opening for the user to access the internal electrical components. Usually, the opening is closed by a cover. A gasket is arranged between the periphery of the opening and the cover to seal between the edge of the opening and the cover. Patent Documents 1 and 2 disclose an inverter in which a gasket is arranged between the opening and the cover. An inverter is a type of electrical device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The housing and the cover are made of conductive materials, but the gasket is often made of non-conductive materials. The housing is often used as the electrical ground (earth) of the internal electrical components. If the housing and the cover are not electrically connected, there may be a potential difference between the housing and the cover. The potential difference between the housing and the cover can cause electromagnetic noise to be radiated through the housing (or electromagnetic noise to enter the housing).

[0005] Generally, the cover is fixed to the housing with bolts. If the cover and the housing are in contact with each other around the bolts, they will conduct electricity. On the other hand, a liquid gasket may be used for the seal between the cover and the housing. The liquid gasket has fluidity in its initial state and is a sealing material that is applied around the housing and then cured by drying or exposure to ultraviolet rays or heat. When using a liquid gasket, there is a risk that the liquid gasket will spread to around the bolts while it has fluidity, impairing the electrical continuity between the cover and the housing around the bolts. This specification provides a technique for ensuring electrical continuity between the housing and the cover in a housing (housing of an electrical device) in which a liquid gasket is used for the seal between the housing and the cover.

Means for Solving the Problems

[0006] The housing disclosed in this specification includes a conductive housing and cover, and a non-conductive gasket. The housing has an opening and a first seating surface is provided around the opening. The cover closes the opening of the housing. The gasket is disposed between the first seating surface and the cover. The housing is provided with a second seating surface located adjacent to the first seating surface, a positioning pin protruding from the second seating surface, and a groove separating the second seating surface from the first seating surface. The cover has a cover body and a tab. The tab extends from the cover body along the second seating surface. The tab is provided with a positioning hole that fits into the positioning pin. The gasket is a liquid gasket that has fluidity before being applied to the first seating surface and cures after being applied. The tab is in contact with the second seating surface and the cover and the housing are electrically connected via the tab.

[0007] In the housing disclosed in this specification, the cover is electrically connected to the housing via a tab that contacts the second seating surface. The second seating surface is separated from the first seating surface by a groove. Even if the liquid gasket applied to the first seating surface spreads around the first seating surface, the excess gasket will fall into the groove and will not reach the second seating surface. That is, the excess gasket will not prevent the electrical continuity between the tab and the housing. That is, the cover is surely electrically connected to the housing.

[0008] The height of the second seating surface may be equal to or greater than the surface height of the gasket. When the cover is attached to the housing, the tab and the second seating surface will surely come into contact with each other.

[0009] Details of the technology disclosed in this specification and further improvements will be described in the following "Mode for Carrying Out the Invention".

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0011] The housing 2 of the embodiment will be described with reference to the drawings. FIG. 1 shows a perspective view of the housing 2. FIG. 2 shows a perspective view of the housing 2 with the cover 20 removed. FIG. 3 shows a cross-sectional view of the housing 2 taken along line III-III of FIG. 1. Only a part of the housing 2 is shown in FIGS. 1-3. Electrical components are housed inside the housing 2. The housing 2 is a housing of an electrical device, specifically, for example, a housing of an inverter.

[0012] The main components of the housing 2 are a housing 10 for housing electrical components and a cover 20. An opening 11 is provided on one surface of the housing 10. The opening 11 is provided for maintenance staff to check the state of the internal electrical components or replace the electrical components. The opening 11 for maintenance may be called an access hole.

[0013] Cover 20 closes the opening 11. Cover 20 is fixed to the housing 10 with bolts 40. The area occupied by the opening 11 is part of one surface of the housing 10, and the housing 10 is provided with a cover pedestal 12 surrounding the opening 11. Cover 20 is attached to the cover pedestal 12. The cover pedestal 12 is provided with two fixing pedestals 12a protruding laterally, and bolt holes 12b are provided on the top surfaces of the respective fixing pedestals 12a.

[0014] Cover 20 is made of a single metal plate. Cover 20 includes a cover body 21 that closes the opening 11, and a fixing tab 23 and a positioning tab 22 extending from the edge of the cover body 21. The fixing tab 23 extends along the top surface of the fixing pedestal 12a. The fixing tab 23 is provided with a bolt hole 23a through which the bolt 40 passes. The bolt 40 passes through the bolt hole 23a of the fixing tab 23 and is fixed to the bolt hole 12b of the fixing pedestal 12a. The top surface of the cover pedestal 12 is hereinafter referred to as the first seating surface 12s.

[0015] The housing 10 is provided with a pin pedestal 13 adjacent to the cover pedestal 12. The cover pedestal 12 and the pin pedestal 13 are both provided on one surface of the housing 10. The top surface of the pin pedestal 13 is referred to as the second seating surface 13s. A positioning pin 14 is provided on the second seating surface 13s. The positioning pin 14 protrudes from the second seating surface 13s.

[0016] A groove 15 is provided between the cover pedestal 12 and the pin pedestal 13. In other words, a groove 15 is provided between the first seating surface 12s and the second seating surface 13s. The groove 15 separates the second seating surface 13s from the first seating surface 12s.

[0017] The positioning tab 22 extends from the edge of the cover body 21 along the second seating surface 13s. In other words, the positioning tab 22 faces the second seating surface 13s. The positioning tab 22 is provided with a positioning hole 22a that fits onto the positioning pin 14.

[0018] When attaching the cover 20 to the housing 10, by passing the positioning pin 14 through the positioning hole 22a, the appropriate relative position of the cover 20 with respect to the cover pedestal 12 is determined. Note that the housing 10 is provided with a plurality of positioning pins, and the cover 20 is provided with a plurality of positioning tabs corresponding to the respective positioning pins. However, in the figure, only one positioning pin 14 and one positioning tab 22 are shown, and the illustration of the other positioning pins and positioning tabs is omitted.

[0019] A gasket 30 is sandwiched between the first seating surface 12s and the cover body 21. In FIG. 2, for the sake of understanding, the surface of the gasket 30 is hatched in gray. The gasket 30 seals between the first seating surface 12s and the cover 20. In other words, the gasket 30 seals around the opening 11. The gasket 30 has fluidity before being applied to the first seating surface 12s, and solidifies after application by drying or ultraviolet irradiation or heating. Such a gasket is called a liquid gasket. A typical example of a liquid gasket is Formed In Place Gasket (commonly known as FIPG). FIPG is a liquid gasket using a foamed foam. After closely adhering two surfaces (sealing surfaces) with the initial FIPG having fluidity in between, the FIPG cures by heating or ultraviolet irradiation or absorption of moisture in the air.

[0020] In order to closely adhere the two sealing surfaces while the FIPG has fluidity, excess FIPG may overflow from the sealing surfaces. In FIG. 2, a state where the excess gasket 30a has spread to around the bolt hole 12b of the fixed base 12a is depicted.

[0021] Although not shown in FIG. 2, there is a possibility that excess gasket spreads outside the first seating surface 12s over the entire area of the first seating surface 12s surrounding the opening 11. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1, and FIG. 3 depicts excess gaskets 30b, 30c that have overflowed from the first seating surface 12s.

[0022] As shown in FIG. 3, the second seating surface 13s is separated from the first seating surface 12s by the groove 15. The excess gasket 30c that overflows from between the cover body 21 and the first seating surface 12s falls into the groove 15 and thus does not reach the second seating surface 13s.

[0023] Incidentally, the housing 10 and the cover 20 are made of conductive materials. If the potential of the housing 10 and the potential of the cover 20 are different, there is a possibility that electromagnetic noise emitted by the electrical components inside the housing 10 may leak outside the housing 2. Alternatively, there is a possibility that electromagnetic noise outside the housing 2 may reach the internal electrical components. Therefore, it is desirable that the housing 10 and the cover 20 have the same potential. On the other hand, the gasket 30 has non-conductivity. Since the non-conductive gasket 30 is sandwiched between the cover body 21 and the first seating surface 12s, the cover body 21 and the first seating surface 12s (housing 10) are not in contact. The bolt 40 is in contact with both the housing 10 and the cover 20, and there is a possibility that the housing 10 and the cover 20 may be electrically connected through the bolt 40. However, the bolt 40 may be made of a material having a relatively large electrical resistance or may be coated with a material having a relatively large electrical resistance. In such a case, a potential difference may remain between the housing 10 and the cover 20 through the bolt 40.

[0024] On the other hand, as described above, the excess gasket falls into the groove 15 and thus does not reach the second seating surface 13s. Therefore, the positioning tab 22 is in contact with the second seating surface 13s (see FIG. 3). The positioning tab 22 is made of the same conductive material as the cover body 21. Therefore, the cover 20 is electrically connected to the housing 10 through the positioning tab 22, and both have the same potential. By providing the groove 15 between the first seating surface 12s and the second seating surface 13s, the housing 10 and the cover 20 are surely electrically connected.

[0025] Also, as shown in FIG. 3, the height H of the second seating surface 13s (the height from the lowest position of the housing 10 to the second seating surface 13s) is the same as the height of the surface of the gasket 30 (gasket surface 30s). This structure also contributes to the reliable contact between the second seating surface 13s and the positioning tab 22 (cover 20). Note that the height H of the second seating surface 13s may be the same as or higher than the height of the gasket surface 30s. When the height H of the second seating surface 13s is higher than the gasket surface 30s, the positioning tab 22 is pushed against the pin pedestal 13 and deformed. The positioning tab 22 comes into firm contact with the second seating surface 13s, and reliable electrical continuity between the housing 10 and the cover 20 is maintained.

[0026] The fact that the height H of the second seating surface 13s is the same as or higher than the height of the gasket surface 30s is equivalent to the height of the second seating surface 13s being higher than the height of the first seating surface 12s.

[0027] Points to note regarding the technology described in the embodiments are described. The housing may include a plurality of positioning pins (positioning pedestals and the second seating surface). The cover may include a plurality of positioning holes corresponding to each positioning pin. The plurality of positioning pins may be provided on a single pin pedestal. Each of the plurality of positioning pins may be provided on each of the plurality of pin pedestals. When the housing includes a plurality of pin pedestals, a groove may be provided between the seating surface (second seating surface) of at least one pin pedestal and the first seating surface.

[0028] The cover may be provided with a hole through which a cable passes or a connector.

[0029] The specific examples of the present invention have been described in detail above. However, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples exemplified above. The technical elements described in this specification or the drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve multiple purposes simultaneously, and achieving one of those purposes itself has technical utility.

Description of Reference Numerals

[0030] 2: Housing 10: Housing 11: Opening 12: Cover Base 12a: Fixed Base 12b, 23a: Bolt Hole 12s: First Seating Surface 13: Pin Base 13s: Second Seating Surface 14: Positioning Pin 15: Groove 20: Cover 21: Cover Body 22: Positioning Tab 22a: Positioning Hole 23: Fixed Tab 30: Gasket 30a, 30b, 30c: Excess Gasket 30s: Gasket Surface 40: Bolt

Claims

1. A housing of an electrical device, having conductivity, having an opening, and having a first seating surface provided around the opening; a cover having conductivity and closing the opening; a gasket having non-conductivity and disposed between the first seating surface and the cover; comprising: The housing is provided with a second seating surface located adjacent to the first seating surface, a positioning pin protruding from the second seating surface, and a groove separating the second seating surface from the first seating surface; The cover has a tab extending along the second seating surface from a cover body and having a positioning hole fitted to the positioning pin; The gasket is a liquid gasket having fluidity before being applied to the first seating surface and curing after application; the tab is in contact with the second seating surface, and the cover and the housing are electrically connected through the tab; a housing.

2. The housing according to claim 1, wherein the height of the second seating surface is equal to or greater than the height of the surface of the gasket.

Images