U.S. patent application number 09/790500 was filed with the patent office on 2001-08-30 for electronic circuit board case.
This patent application is currently assigned to Keihin Corporation. Invention is credited to Kikuchi, Satoshi, Kitamura, Nobuyuki.
Application Number | 20010017767 09/790500 |
Document ID | / |
Family ID | 18570166 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010017767 |
Kind Code |
A1 |
Kitamura, Nobuyuki ; et
al. |
August 30, 2001 |
Electronic circuit board case
Abstract
A case for an electronic circuit board mounted with electronic
components having a case main body whose one end is opened, an
opening formed at an outer periphery of the open end of the case
main body; and retaining means such as rails, projections, recess
for retaining the electronic circuit board inserted through the
open end at a prescribed position in the case main body. With this,
the electronic circuit board can be immobilized at the prescribed
position in the case main body and the strength of the case (i.e.
case main body), particularly the strength of the open end thereof,
can be increased. Moreover, when resin is potted in the case main
body, any resin that runs out from the open end can be caused to
flow into the opening.
Inventors: |
Kitamura, Nobuyuki;
(Shioya-gun, JP) ; Kikuchi, Satoshi; (Shioya-gun,
JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN, HATTORI,
MCLELAND & NAUGHTON, LLP
1725 K STREET, NW, SUITE 1000
WASHINGTON
DC
20006
US
|
Assignee: |
Keihin Corporation
Tokyo
JP
|
Family ID: |
18570166 |
Appl. No.: |
09/790500 |
Filed: |
February 23, 2001 |
Current U.S.
Class: |
361/752 |
Current CPC
Class: |
H05K 5/0039
20130101 |
Class at
Publication: |
361/752 |
International
Class: |
H05K 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 24, 2000 |
JP |
2000-048013 |
Claims
What is claimed is:
1. A case for an electronic circuit board mounted with electronic
components, comprising: a case main body whose one end is opened;
an opening formed at an outer periphery of the open end of the case
main body; and retaining means for retaining the electronic circuit
board inserted through the open end at a prescribed position in the
case main body.
2. A case according to claim 1, wherein the opening is provided
with a catcher such that resin potted in the case main body is
caught by the catcher, when overflowing the open end.
3. A case according to claim 1, wherein a notch is formed at a
portion of the open end where the case main body and a part of the
electronic components are in close proximity with each other.
4. A case according to claim 1, wherein a rib is formed to
interconnect the open end and the catcher across the opening.
5. A case according to claim 1, wherein the retaining means
comprises at least the resin potted in the case main body, rails
formed on an inner wall of the case main body, and a projection
formed on a part of the electronic components to engage with a
portion of the case main body close to the open end.
6. A case according to claim 1, wherein the case main body is
formed to have an irregular profile matched to the shape of the
electronic components.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an electronic circuit board case,
particularly to a case for accommodating an electronic circuit
board mounted with electronic components wherein resin is potted or
charged into the space between the accommodated electronic circuit
board and the inner wall of the case to immobilize and protect the
electronic circuit board.
[0003] 2. Description of the Related Art
[0004] An electronic circuit board mounted on a motorcycle or
vehicle or the like must be protected from electronic component
lead breakage and pattern exfoliation caused by shock and vibration
imparted thereto from the exterior and also from corrosion and
shortcircuiting defects caused by water immersion and moisture
invasion. The electronic circuit board is therefore accommodated in
a case and resin is potted or charged into the space between the
electronic circuit board and the inner wall of the case to
immobilize and protect the electronic circuit board.
[0005] FIG. 5 is a sectional view of a conventional electronic
circuit board case.
[0006] A case 10 shown in FIG. 5, more specifically, a case main
body 12 of the case, accommodates an electronic circuit board 16
inserted therein through an open end 14 at the top of the case.
Connectors 18 and other electronic components are mounted on the
electronic circuit board 16. (Electronic components other than the
connectors 18 are omitted from the drawing.)
[0007] After accommodation of the electronic circuit board 16 has
been completed, resin 20 is potted or charged into the space
between the inner wall of the case main body 12 and the electronic
circuit board 16. The resin 20 is potted or charged up to a level
near the open end 14, more specifically up to a level where the
cured resin 20 can retain (immobilize) and protect the electronic
circuit board 16 and the connectors 18.
[0008] Further, Japanese Laid-open Patent Application No. Sho
62(1987)-95897, for example, teaches insertion of the electronic
circuit board into the case after the case has been potted or
charged with resin.
[0009] Since it is a property of the resin 20 to undergo a
temporary decrease in viscosity during curing, the resin can
penetrate even into the fine regions of the space between the case
main body 12 and both the electronic circuit board 16 and
electronic components. On the other hand, when the resin 20 is
potted or charged to the foregoing level, it moves into the space
between the case main body 12 and the connectors 18 owing to
capillary action, overflows the open end 14 of the case main body
12, and runs out to the exterior.
[0010] This will be explained in further detail with reference to
FIG. 6. Capillary action arising at a gap portion 22 between the
case main body 12 and the connectors 18 causes the resin 20 to move
toward the portions indicated by A and B in FIGS. 5, i.e., toward
the portions where the case main body 12 and the connectors 18 are
in contact (as indicated by the arrows in FIG. 6). The resin 20
then overflows the open end 14 in the vicinity of A and B and runs
out to the exterior of the case 10.
[0011] The overflowing resin 20 sticks to the outside of the case
main body 12 and spoils its appearance. Extra processing, such as a
wiping step, has therefore been necessary.
[0012] Conventional practices for preventing outflow of the resin
20 include sealing the places where the resin 20 flows out by
application of an adhesive or the like or potting or charging the
resin 20 with the case 10 tilted about 15 degrees in the direction
of the arrow in FIG. 5 so as to prevent potting or charging of
resin into the portions that give rise to capillary action.
Although these techniques are effective for preventing outflow of
the resin 20, they do not help to prevent an increase in the number
of fabrication steps.
[0013] On the other hand, when the electronic circuit board is
inserted into the case after it has been potted or charged with
resin, the resin is apt to overflow at the time of inserting the
electronic circuit board.
[0014] When the case is used in an environment where it is exposed
to shock and vibration, moreover, the strength of the case,
particularly the strength of the open end thereof, is preferably
increased. In addition, it is preferable to be able to retain
(immobilize) the accommodated electronic circuit board and
electronic components with high reliability.
[0015] Although Japanese Laid-open Patent Application Nos. Sho 62
(1987)-95897, Hei 10 (1998)-22312, Hei 8 (1996)-167455 and Hei 6
(1994)-243919, among others, teach techniques for resolving the
foregoing issues, none solves them all.
SUMMARY OF THE INVENTION
[0016] An object of this invention is therefore to provide an
electronic circuit board case that, without requiring any increase
in number of fabrication steps, can prevent sticking of resin to
the case exterior, is enhanced in strength, particularly the
strength of the open end, and can reliably retain (immobilize) and
protect an accommodated electronic circuit board and electronic
components.
[0017] For realizing this object, a first aspect of this invention
provides a case for an electronic circuit board mounted with
electronic components, comprising: a case main body whose one end
is opened; an opening formed at an outer periphery of the open end
of the case main body; and retaining means for retaining the
electronic circuit board inserted through the open end at a
prescribed position in the case main body.
[0018] Since the case is formed with an opening at the outer
periphery of the open end of the case main body and with the
retaining means for retaining the electronic circuit board inserted
through the open end at a prescribed position in the case main
body, the electronic circuit board can be immobilized at the
prescribed position in the case main body and the strength of the
case (i.e. case main body), particularly the strength of the open
end thereof, can be increased. Moreover, when resin is potted or
charged into the case main body, any resin that runs out from the
open end can be caused to flow into the opening.
[0019] In a second aspect, the present invention provides the case,
wherein the opening is provided with a catcher such that resin
potted in the case main body is caught by the catcher, when
overflowing the open end.
[0020] Since the opening is provided with a catcher and any resin
potted or charged into the case may body that overflows the open
end and runs out to the exterior is caught by the catcher, the
resin running out to the exterior of the case main body can be
prevented from sticking to the outside of the case main body.
[0021] In a third aspect, the present invention provides the case,
wherein a notch is formed at a portion of the open end where the
case main body and a part of the electronic components are in close
proximity with each other.
[0022] Since a notch is formed at a portion of the open end where
the case main body and a part of the electronic components are in
close proximity or in contact with each other, the space (gap)
between the case main body and the electronic components concerned
is enlarged. Since occurrence of capillary action is therefore
inhibited, flow of resin to the exterior of the case main body is
reduced.
[0023] In a fourth aspect, the present invention provides the case,
wherein a rib is formed to interconnect the open end and the
catcher across the opening.
[0024] Since a rib is formed to interconnect the open end and the
catcher across the opening, the strength of the case (i.e., case
main body), particularly the strength of the open end thereof, is
further increased.
[0025] In a fifth aspect, the present invention provides the case,
wherein the retaining means comprises at least the resin potted in
the case main body, rails formed on an inner wall of the case main
body, and a projection formed on a part of the electronic
components to engage with a portion of the case main body close to
the open end.
[0026] Since the retaining means comprises at least the resin
potted or charged into the case, rails formed on an inner wall of
the case main body, and a projection formed on some of the
electronic components to engage with a portion of the case main
body close to the open end, the electronic circuit board can be
reliably introduced and immobilized at the prescribed position.
Resistance of the electronic circuit board against shock and
vibration imparted from the exterior is therefore enhanced.
[0027] In the sixth aspect, the present invention provides the
case, wherein the case main body is formed to have an irregular
profile matched to the shape of the electronic components.
[0028] Since the case main body is formed to have an irregular
profile matched to the shape of the electronic components, the
volume of the case (i.e. case main body) can be made small and the
amount of potted or charged resin reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The above and other objects and advantages of the invention
will be more apparent from the following description and drawings,
in which:
[0030] FIG. 1 is a perspective view showing an electronic circuit
board case according to a first embodiment of the present
invention;
[0031] FIG. 2 is a perspective view for explaining the electronic
circuit board case according to the first embodiment;
[0032] FIG. 3 is a sectional view of the electronic circuit board
case according to the first embodiment;
[0033] FIG. 4 is a perspective view showing an electronic circuit
board case according to a second embodiment of the present
invention;
[0034] FIG. 5 is a sectional view of an electronic circuit board
case according to the prior art; and
[0035] FIG. 6 is a perspective view for explaining resin movement
in the electronic circuit board case according to the prior
art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] An electronic circuit board case according to an embodiment
of the present invention will now be explained with reference to
FIGS. 1 to 3. Constituents similar to those of the prior art are
assigned like reference symbols and will not be explained
again.
[0037] FIG. 1 is a perspective view showing an electronic circuit
board case according to a first embodiment of the present
invention.
[0038] A case 26 comprises a case main body 28 which has the
general shape of a rectangular prism, is formed at its top with an
open end 14. Rails 30 for guiding an electronic circuit board 16
to, and immobilizing it at, a prescribed position in the case main
body 28 are formed on an inner wall of the case main body 28.
Specifically, paired rails 30 are formed opposite to each other at
appropriate locations on the floor and inner wall of the case main
body 28 so as to form grooves of a width substantially equal to the
thickness of an electronic circuit board 16. A plurality of
recesses 34 for engaging projections 32 (explained next) are formed
near the open end 14. A plurality of connectors 18 are mounted on
the electronic circuit board 16 by soldering and the projections 32
for engagement with the associated recesses 34 are formed as
flange-like members at the bottom of sidewalls of the connectors
18.
[0039] The electronic circuit board 16 is fixed at a prescribed
position by inserting it into the case main body 28 so as to be
held in the case main body 28 by the rails 30, specifically by
introducing it into the grooves formed by the paired rails 30. The
upper edges of the rails 30 are tapered to facilitate introduction
(insertion) of the electronic circuit board 16. In addition, the
projections 32 fit into the associated recesses 34. The electronic
circuit board 16 and the connectors 18 can therefore be firmly
fixed at their prescribed locations.
[0040] An opening 36 for inflow of resin 20 (not shown in FIG. 1)
overflowing the open end 14 to the outside of the case 26 are
formed at the outer periphery of the open end 14. The opening 36 is
defined by a plurality of catchers 38 integrally formed for
retaining resin 20 that flows into the opening 36. Notches 40 for
inhibiting capillary action are formed at portions of the open end
14 where the case main body 28 and the connectors 18 are in close
proximity or in contact with each other. A plurality of ribs 42 are
formed to interconnect the open end 14 and vertical portions of the
catchers 38 across the opening 36 in a manner suitable for
increasing the strength of the case main body 28, particularly its
open end 14.
[0041] A more detailed description will now be made with reference
to FIG. 2.
[0042] The catchers 38 are formed integrally with the outer
periphery of the open end 14 of the case main body 28 in a
generally L-like (or reversed L-like) shape so as to define the
opening 36. Although not shown in FIG. 2, resin 20 that overflows
the open end 14 and runs out to the exterior of the case 26 enters
the opening 36 to be retained by the catchers 38. Sticking of resin
to the outer surface of the case main body 28 is therefore
prevented.
[0043] The notches 40 are formed at portions of the open end 14
where the case main body 28 and the connectors 18 are in close
proximity or in contact with each other. When, as shown in FIG. 3,
the resin 20 is potted or charged up to the vicinity of the open
end 14, i.e., up to a level enabling the resin 20 to retain
(immobilize) and protect the electronic circuit board 16 and the
connectors 18 after it hardens, capillary action arises in the
space (gap) between the case main body 28 and the connectors
18.
[0044] Since the degree of the capillary action is inversely
proportional to the size of the gap, however, the capillary action
can be inhibited by formation of the notches 40, i.e., by
deliberately enlarging the space between the case main body 28 and
the connectors 18. By inhibiting the occurrence of capillary
action, it is in turn possible to reduce outflow of the resin 20 to
the outside of the case main body 28. Excellent capillary action
preventing effect can be obtained with a gap of around 1 mm.
[0045] In addition, the strength of the case main body 28,
particularly the strength of its open end 14, is increased by
forming a number of ribs 42 perpendicularly interconnecting the
open end 14 and the vertical portions of the catchers 38 across the
opening 36.
[0046] Being configured as described in the foregoing, the first
embodiment of the present invention provides the electronic circuit
board case that, without requiring any increase in number of
fabrication steps, can prevent sticking of the resin 20 to the
exterior of the case main body 28, is enhanced in the strength of
the case main body 28, particularly the strength of the open end
14, and can reliably retain (immobilize) and protect an
accommodated electronic circuit board 16 and electronic components
(connectors 18 etc.).
[0047] An electronic circuit board case according to a second
embodiment of the present invention will now be explained.
[0048] FIG. 4 is a perspective view showing an electronic circuit
board case according to a second embodiment of the present
invention.
[0049] The electronic circuit board case according to the second
embodiment of the present invention, designated by reference
numeral 46, comprises a case main body 48 that is formed to have an
irregular profile matched to the shape of electronic components
(not shown) mounted on the electronic circuit board 16. Since the
other constituents of the case 46 are the same as those of the case
26, they are denoted by like reference symbols and will not be
explained again here.
[0050] Being configured as described in the foregoing, the second
embodiment of the present invention provides the electronic circuit
board case that, in addition to the advantageous effects described
above with regard to the first embodiment, further enables the
volume of the case main body 48 to be made small and thus reduces
the amount of potted or charged resin 20.
[0051] Thus, the embodiments are configured to provides a case (26,
46) for an electronic circuit board (16) mounted with electronic
components, comprising: a case main body (28, 48) whose one end
(14) is opened; an opening (36) formed at an outer periphery of the
open end (14) of the case main body; and retaining means (rails 30,
projection 32, recess 34) for retaining the electronic circuit
board inserted through the open end at a prescribed position in the
case main body.
[0052] Since the case is formed with an opening at the outer
periphery of the open end of the case main body and with the
retaining means for retaining the electronic circuit board inserted
through the open end at a prescribed position in the case main
body, the electronic circuit board can be immobilized at the
prescribed position in the case main body and the strength of the
case (i.e. case main body), particularly the strength of the open
end thereof, can be increased. Moreover, when resin is potted or
charged into the case main body, any resin that runs out from the
open end can be caused to flow into the opening.
[0053] In the case, wherein the opening (36) is provided with a
catcher (38) such that resin (20) potted in the case main body is
caught by the catcher, when overflowing the open end (14).
[0054] Since the opening is provided with a catcher and any resin
potted or charged into the case may body that overflows the open
end and runs out to the exterior is caught by the catcher, the
resin running out to the exterior of the case main body can be
prevented from sticking to the outside of the case main body.
[0055] In the case, wherein a notch (40) is formed at a portion of
the open end where the case main body and a part (connectors 18) of
the electronic components are in close proximity with each
other.
[0056] Since a notch is formed at a portion of the open end where
the case main body and a part of the electronic components are in
close proximity or in contact with each other, the space (gap)
between the case main body and the electronic components concerned
is enlarged. Since occurrence of capillary action is therefore
inhibited, flow of resin to the exterior of the case main body is
reduced.
[0057] In the case, wherein a rib (42) is formed to interconnect
the open end (14) and the catcher across the opening (36).
[0058] Since a rib is formed to interconnect the open end and the
catcher across the opening, the strength of the case (i.e., case
main body), particularly the strength of the open end thereof, is
further increased.
[0059] In the case, wherein the retaining means comprises at least
the resin (20) potted in the case main body, rails (30) formed on
an inner wall of the case main body, and a projection (32) formed
on a part of the electronic components to engage with a portion of
the case main body close to the open end.
[0060] Since the retaining means comprises at least the resin
potted or charged into the case, rails formed on an inner wall of
the case main body, and a projection formed on some of the
electronic components to engage with a portion of the case main
body close to the open end, the electronic circuit board can be
reliably introduced and immobilized at the prescribed position.
Resistance of the electronic circuit board against shock and
vibration imparted from the exterior is therefore enhanced.
[0061] In the case, wherein the case main body (28, 48) is formed
to have an irregular profile matched to the shape of the electronic
components.
[0062] Since the case main body is formed to have an irregular
profile matched to the shape of the electronic components, the
volume of the case (i.e. case main body) can be made small and the
amount of potted or charged resin reduced.
[0063] Although the invention was described with regard to
embodiments in which the opening 36 and the catchers 38 are formed
only along the long sides of the open end 14, they can instead be
formed over the entire outer periphery of the open end 14.
[0064] Moreover, the opening 36 and the catchers 38 are not limited
to the illustrated shapes but can instead be configured in any of
various other shapes enabling inflow and retention of the resin
20.
[0065] Although the ribs 42 were described as perpendicularly
interconnecting the open end 14 and the vertical portions of the
catchers 38 across the opening 36, the invention is not limited to
this configuration and the ribs 42 can instead be configured in any
of various other ways providing structural reinforcement.
[0066] Although the electronic circuit board 16 is secured by two
immobilizing means, the rails 30 and the recesses 34, in the
described embodiments, provision of only one these means
suffices.
[0067] Although a plurality of the catchers 38, the ribs 42, etc.
are illustrated, only one number of them may sometimes be
sufficient. Only one projection 32 may sometimes be sufficient for
the associated recess 34.
[0068] While the invention has thus been shown and described with
reference to specific embodiments, it should be noted that the
invention is in no way limited to the details of the described
arrangements; changes and modifications may be made without
departing from the scope of the appended claims.
* * * * *