Electricity: conductors and insulators – Anti-inductive structures – Conductor transposition
Reexamination Certificate
1999-11-09
2001-11-13
Tso, Edward H. (Department: 2838)
Electricity: conductors and insulators
Anti-inductive structures
Conductor transposition
Reexamination Certificate
active
06316720
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an opening shield plate used as an opening shield lid of an electrolyte capacitor.
A opening shield plate
51
shown in
FIG. 6
is conventionally known and structured as follows.
Namely, first of all, a resin made opening shield member
53
in the form of a plate to be pressed to fix to a circumferential edge portion of an upper opening portion of a capacitor case
52
is provided. Aluminum terminals
54
are bonded to the resin made opening shield member
53
by an insert molding. As known well, in the insert molding, the aluminum terminals
54
are inserted into a cavity of molds for molding the resin made opening shield member
53
for molding, and the two components
53
and
54
are bonded to each other simultaneously with the completion of the molding.
A packing
55
made of rubber elastic material is interposed between the capacitor case
52
and the resin made shield member
53
in order to prevent the electrolyte contained in the case
52
from leaking to the outside from the press-fit portion between the resin made opening shield member
53
and the capacitor case
52
. Reference numeral
56
denotes a capacitor element received in the interior of the capacitor case
52
, reference numeral
57
denotes lead lines for connecting the capacitor element
56
and aluminum terminals
54
, and reference numeral
58
denotes an explosion preventing valve for releasing an excessive pressure.
However, the above-described conventional opening shield plate
51
has the following disadvantages. Namely, in the case where an electrolyte liquid is type of a high permeation, if this electrolyte permeates into the press-fit portion to be brought into contact with the packing
55
, there is a fear that the packing
55
would be deteriorated relatively earlier by the chemical reaction. Accordingly, since it is impossible to sufficiently seal the electrolyte liquid only with the deteriorated packing
55
, there is a fear that the electrolyte liquid would out leak from the interface between the resin made opening shield member
53
and the capacitor case
52
, i.e., the interface between the opening shield plate
51
and the capacitor case
52
.
Also, with respect to the interface between the resin made opening shield member
53
and the aluminum terminals
54
, there is a fear that a gap would be formed gradually due to the fact that there is a difference in thermal expansion rate or thermal transfer rate between the two components
53
and
54
and the electrolyte liquid would leak out through the gap. In this connection, the present applicant has proposed the approach that a flanged portion
54
a is integrally formed with an outer circumference of each aluminum terminal
54
as shown in the drawing and the flanged portion
54
a
is embedded within the thickness of the resin made opening shield member
53
to enhance the bondability between the two components
53
and
54
(see Utility Model Publication No. 21222/1994). However, if the bondability between the two components
53
and
54
or the sealability there between is further enhanced, this would be by far better.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide an opening shield plate which enhances the bondability or the sealability between the opening shield plate and a capacitor case and between a resin made opening shield member and aluminum terminals and which can suppress effectively a leakage of electrolyte liquid from these interfaces.
In order to attain the above-described and other objects, there is provided an opening shield plate comprising a resin opening shield member bonded to an outer circumference of an aluminum terminal and an aluminum opening shield member bonded to the resin opening shield member characterized in that the resin opening shield member is made of PFA (tetrafluoroethylene-perfluoroalkylvinylether) resin, and the aluminum opening shield member is welded to a capacitor case.
In the opening shield plate provided with the above-described arrangement according to the present invention, first, the aluminum made opening shield member is bonded to the outer circumference of the resin made opening shield member, and at the same time, the aluminum made opening shield member is welded to the capacitor case. Accordingly, if the aluminum made opening shield member is welded to the capacitor case when the opening shield plate is mounted in place, there is no room for any gap to be generated between the two components, thus, it is possible to prevent the electrolyte from leaking from the interface between the two components even if any packing is not interposed between the two components.
Further, the PFA resin that has been selected for the resin made opening shield member has an anti-chemical property as its characteristic. Also, a sort of chemical bond is generated on the bonded interface with the aluminum to exhibit the excellent bondability. Accordingly, since the bondability between the resin made opening shield member and the aluminum terminal is strengthened on the basis of the characteristics of the PFA resin, it is thus possible to prevent any gap from being formed between the two components.
Accordingly, the present invention can obtain the following advantages. Namely, in the opening shield plate provided with the above-described arrangement, first, the aluminum made opening shield member is bonded to an outer circumference of the resin made opening shield member which is bonded to the outer circumference of the aluminum terminal, and the aluminum made opening shield member is welded to the capacitor case. Accordingly, even if any packing is not interposed between the two components as in the conventional technology, it is possible to completely seal the interface between the two components, i.e., the opening shield plate and the capacitor case.
Further, the resin made opening shield member is firmly bonded to the aluminum terminal on the basis of the characteristics of the PFA resin which has been selected as the material for the resin made opening shield member. As a result, it is possible to enhance the sealability between the two components without forming any gap between the two components
2
to thereby enhance the sealability therebetween.
Accordingly, from the foregoing advantages, it is possible to enhance the sealability between the aluminum terminal and the resin made opening shield member which is a component of the opening shield plate, and between the opening shield plate and the capacitor case, to thereby effectively suppress the leakage of the electrolyte from the interface therebetween. Thus, it is possible to prevent the degradation of the capacitor caused by the leakage of the electrolyte.
REFERENCES:
patent: 621222 (1994-06-01), None
Andou Kazuo
Matsumoto Kenji
Matsune Jo
Yamamoto Yoshio
Dykema Gossett PLLC
Honda Giken Kogyo Kabushiki Kaisha
Tso Edward H.
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