FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
VENTILATION MECHANISM FOR ELECTRONIC DEVICE HOUSING;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

DESCRIPTION
TECHNICAL FIELD
[0001] The present disclosure relates to a ventilation
mechanism of an electronic device housing.

BACKGROUND ART
[0002] Housings of electronic devices such as an
10 electronic control device including therein a heat-generating
component need to moderate pressure fluctuations caused by
changes in the temperatures inside the devices, and include
ventilation mechanisms which allow ventilation between the
inside and the outside of the devices while ensuring a
waterproof function. Regarding a conventional ventilation
mechanism of an electronic control device, a ventilation unit
which is a component separate from a case of the electronic
control device is inserted in an opening provided in the case.
[0003] For example, a ventilation unit disclosed in Patent
Document 1 is composed of: a ventilation member attached in
an opening of a case; a seal member such as an O ring, for
sealing a gap between the case and the ventilation member;
and an annular partition wall member into which the
ventilation member is fitted. Further, the above-described
ventilation member includes: a waterproof ventilation film
for covering the opening of the case; a support supporting
the waterproof ventilation film and to be fixed to the case;
and a cover component covering the waterproof ventilation
film.

CITATION LIST
PATENT DOCUMENT
[0004] Patent Document 1: Japanese Patent No. 5714402
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0005] As indicated in Patent Document 1, the conventional
ventilation unit includes the seal member, the partition wall
member, and the like in addition to the ventilation member
composed of a plurality of components. Accordingly, the
ventilation unit has a large number of components and is
structurally complex. Thus, an electronic control device in
which the conventional ventilation unit is used has a problem
that the number of components is large and machinability is
poor.
[0006] The present disclosure has been made to solve the
above problems, and an object of the present disclosure is to
achieve reduction in the number of components of a
ventilation mechanism of an electronic device housing and
improvement in machinability.

SOLUTION TO THE PROBLEMS
[0007] A ventilation mechanism of an electronic device
housing according to the present disclosure is a ventilation
mechanism for a housing accommodating an electronic device,
the ventilation mechanism including: a projection integrated
with the housing and projecting outward of the housing; a
wall integrated with the housing and disposed on an outer
side of the housing so as to enclose the projection; a window
formed in a part of a side surface of the projection and
facing an inner circumferential surface of the wall; a
through hole forming, together with the window, a ventilation
path which allows communication between an outside and an
inside of the housing; and a water-repellent filter attached
to a region, on an inner side of the housing, that includes
the projection and the through hole.
EFFECT OF THE INVENTION
[0008] In the ventilation mechanism of the electronic
device housing according to the present disclosure, the
ventilation path is formed by the through hole and the window
formed in the side surface of the projection integrated with
the housing, and entry of water into the ventilation path is
prevented by the wall integrated with the housing.
Accordingly, the only constituent component of the
ventilation mechanism other than the housing is one component,
i.e., the water-repellent filter. This achieves reduction in
the number of components of the ventilation mechanism and
improvement in machinability while ensuring a waterproof
function.
Objects, features, viewpoints, and effects of the
present disclosure other than the above-described ones will
be more clarified from the following detailed description
with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
[0009] [FIG. 1] FIG. 1 is a perspective view of an
electronic control device having a ventilation mechanism
according to embodiment 1.
15 [FIG. 2] FIG. 2 is a cross-sectional view of the
ventilation mechanism of the electronic control device
according to embodiment 1.
[FIG. 3] FIG. 3 is a cross-sectional view of the
ventilation mechanism of the electronic control device
according to embodiment 1.
[FIG. 4] FIG. 4 is a plan view indicating the
ventilation area of a water-repellent filter of the
ventilation mechanism according to embodiment 1.
[FIG. 5] FIG. 5 is a partial cross-sectional view
of molds for molding a case of the electronic control device
according to embodiment 1.
[FIG. 6] FIG. 6 is a partial cross-sectional view
of the molds for molding the case of the electronic control
device according to embodiment 1.
[FIG. 7] FIG. 7 is a cross-sectional view of a
ventilation mechanism of an electronic control device
according to embodiment 2.
[FIG. 8] FIG. 8 is a cross-sectional view of a
ventilation mechanism of an electronic control device
10 according to embodiment 3.
[FIG. 9] FIG. 9 is a partial cross-sectional view
of molds for molding a case of the electronic control device
according to embodiment 3.

DESCRIPTION OF EMBODIMENTS
[0010] Embodiment 1
Hereinafter, a ventilation mechanism of an
electronic device housing according to embodiment 1 will be
described with reference to the drawings, with a ventilation
mechanism for a housing of an electronic control device being
used as an example. FIG. 1 is a perspective view of an
electronic control device having a ventilation mechanism
according to embodiment 1. FIG. 2 and FIG. 3 show the
ventilation mechanism of the electronic control device
according to embodiment 1. FIG. 2 is a cross-sectional view
taken along a line indicated by A-A in FIG. 1, and FIG. 3 is
a cross-sectional view taken along a line indicated by B-B in
FIG. 1. FIG. 4 is a plan view indicating the ventilation
area of a water-repellent filter. In the drawings, identical
and corresponding portions are denoted by the same reference
characters.
[0011] As shown in FIG. 1, a housing 1 of an electronic
control device 100 includes a case 2 and a base 3. In the
housing 1, a control board (not shown) mounted with an
electronic component is accommodated. An upper surface 2a of
the case 2 is provided with a ventilation mechanism 10 which
allows ventilation between the inside and the outside of the
housing 1. On a side surface of the case 2, connectors 4 for
connecting the control board and external devices to each
other are disposed. The inside of the housing 1 experiences
change in the temperature due to a heat-generating component
or cooling means for the heat-generating component. A
pressure fluctuation caused by the change in the temperature
is moderated by the ventilation mechanism 10.
[0012] A structure of the ventilation mechanism 10
according to embodiment 1 will be described with reference to
FIG. 1 to FIG. 4. In the following description, a dimension
in a direction perpendicular to the upper surface 2a of the
case 2 on which the ventilation mechanism 10 is disposed is
referred to as a height dimension, and a dimension in a
direction parallel to the upper surface 2a of the case 2 is
referred to as a width dimension. The ventilation mechanism
includes walls 11a and 11b (collectively referred to as
walls 11), a projection 13, windows 14a and 14b (collectively referred to as windows 14), through holes 15a and 15b
(collectively referred to as through holes 15), and a waterrepellent
filter 17.
[0013] The projection 13 projects outward of the case 2,
and the walls 11 are disposed on an outer side of the case 2
so as to enclose the projection 13. The projection 13 and
the walls 11 are integrated with the case 2. Each window 14
formed in a part of a side surface of the projection 13 faces
an inner circumferential surface 110 of the corresponding
wall 11. Below the window 14, the corresponding through hole
15 15 penetrating the case 2 is formed. The through hole 15
forms, together with the window 14, a ventilation path which
allows communication between an outside and an inside of the
housing 1.
[0014] As shown in FIG. 2, in a cross section of the
ventilation mechanism 10, an imaginary straight line L1
obtained by extending a radially outermost portion of a
through hole 15 coincides with the radially outermost portion
of the projection 13. In embodiment 1, the height dimension
of the wall 11 is slightly smaller than the height dimension
25 of the projection 13 and larger than the height dimension of
the window 14. The width dimension of the window 14 is
smaller than the width dimension of the inner circumferential
surface 110 of the wall 11 facing the window 14. The opening
area of the window 14 is smaller than the area of the inner
circumferential surface 110 of the wall 11 facing the window
14. A top portion 133 of the projection 13 is present above
the window 14 and serves as eaves. With such a configuration,
water is less likely to be directly splattered on the window
14, whereby entry of water into the ventilation path can be
prevented.
[0015] In embodiment 1, two circular arc-shaped walls 11a
and 11b are disposed so as to be apart from each other, and
the walls 11a and 11b have cuts 12 therebetween. Each cut 12
serves as a path through which water flows out when water is
splattered on the ventilation mechanism 10. Thus, no windows
14 are provided in side surfaces, of the projection 13, that
face the cuts 12 of the walls 11.
[0016] As shown in FIG. 2 and FIG. 3, an annular enclosing
portion 16 integrated with the case 2 is disposed on an inner
wall 2b on an inner side of the case 2, and the waterrepellent
filter 17 is disposed within the enclosing portion
16. The enclosing portion 16 has functions as a positioning
member and a guard fence for the water-repellent filter 17.
The water-repellent filter 17 is attached to a region, on the25 inner side of the case 2, that includes the projection 13 and
the through holes 15. The water-repellent filter 17 repels
water drops, and thus, even if water enters either through
hole 15, entry of water into the housing 1 can be prevented.
[0017] The water-repellent filter 17 is adhered, at an
adhesion portion 171 near the outer rim thereof, to the inner
wall 2b of the case 2, and a gap 18 is provided between a
bottom surface 131 of the projection 13 and the waterrepellent
filter 17. Accordingly, even when the waterrepellent
filter 17 vibrates, the water-repellent filter 17
does not come into contact with the bottom surface 131 of the
projection 13, whereby damage to the water-repellent filter
17 can be prevented.
[0018] The ventilation area of the water-repellent filter
17 will be described with reference to FIG. 4. In FIG. 4, a
dotted region 17a indicates the ventilation area of the
water-repellent filter 17, and a dotted line indicates a
region facing the bottom surface 131 of the projection 13.
The water-repellent filter 17 has a substantially circular
shape, and the region 17a indicating the ventilation area of
the water-repellent filter 17 includes: the region facing the
bottom surface 131 of the projection 13; and regions 17b and
17c facing the through holes 15a and 15b. In this manner, if
the gap 18 is provided between the bottom surface 131 of the
projection 13 and the water-repellent filter 17, a
ventilation area that occupies a major part of the area of
the water-repellent filter 17 is ensured.
[0019] A producing method for the ventilation mechanism 10
according to embodiment 1, particularly, a method for forming
the windows 14 and the through holes 15, will be described
5 with reference to FIG. 5 and FIG. 6. FIG. 5 and FIG. 6 are
partial cross-sectional views of molds for molding the case
of the electronic control device. FIG. 5 shows a cross
section of the molds in molding for the cross section of the
ventilation mechanism shown in FIG. 2, and FIG. 6 shows a
cross section of the molds in molding for the cross section
of the ventilation mechanism shown in FIG. 3. The molds for
forming the case 2 include an upper mold 20 and a lower mold
21.
[0020] As shown in FIG. 5, the lower mold 21 has through
hole forming portions 22 for forming the through holes 15.
The outer surfaces of the through hole forming portions 22
and the upper mold 20 are in contact with each other, and
contact surfaces 23 are present on the upper mold 20 and the
lower mold 21. A cavity 24 is formed on the inside between
the upper mold 20 and the lower mold 21. The cavity 24
includes: wall forming portions 24a for forming the walls 11;
a projection forming portion 24b for forming the projection
13; and an enclosing portion forming portion 24c for forming
the enclosing portion 16.
[0021] Resin is caused to flow into the cavity 24 and
cured, and then the upper mold 20 and the lower mold 21 are
removed. Consequently, the contact surfaces 23 form the
windows 14, and each through hole 15 and the corresponding
window 14 are in communication with each other. In the cross
5 section of the molds shown in FIG. 5, the radially outermost
portion of each through hole forming portion 22, the
corresponding contact surface 23, and the radially outermost
portion of the projection forming portion 24b are on the same
straight line.
[0022] With such upper mold 20 and lower mold 21, it is
possible to easily form: the projection 13 having the window
in a part of the side surface thereof; and the through
hole 15 in communication with the window 14. In addition,
the wall 11 and the enclosing portion 16 can also be formed
at the same time. Thereafter, the water-repellent filter 17
is attached within the enclosing portion 16 formed on the
inner wall 2b of the case 2, whereby the ventilation
mechanism 10 is completed.
[0023] As described above, in embodiment 1, the
ventilation path is formed by the through hole 15 and the
window 14 formed in the side surface of the projection 13
integrated with the case 2, and entry of water into the
ventilation path is prevented by the wall 11 integrated with
the case 2. Accordingly, the only constituent component of
the ventilation mechanism 10 other than the case 2 is one
component, i.e., the water-repellent filter 17. This
achieves reduction in the number of components of the
ventilation mechanism 10 and improvement in machinability
while ensuring a waterproof function.
[0024] In addition, the height dimension of the wall 11
facing the window 14 is set to be larger than the height
dimension of the window 14, and the width dimension of the
window 14 is set to be smaller than the width dimension of
the inner circumferential surface 110 of the wall 11.
Accordingly, entry of water into the ventilation path can be
inhibited, whereby the waterproof function can be ensured.
Further, since the gap 18 is provided between the bottom
surface 131 of the projection 13 and the water-repellent
filter 17, the ventilation area of the water-repellent filter
17 can be ensured, whereby a ventilation function can be
ensured.
[0025] Embodiment 2
FIG. 7 is a partial cross-sectional view of a
ventilation mechanism of an electronic control device
according to embodiment 2. A ventilation mechanism 10A
according to embodiment 2 is a modification of the abovedescribed
ventilation mechanism 10 according to embodiment 1
and is the same as the ventilation mechanism 10 in terms of
the main configuration, the producing method, and the like.
Thus, only the differences therebetween will be briefly
described here.
[0026] In the above-described embodiment 1, the height
dimension of the wall 11 is set to be slightly smaller than
the height dimension of the projection 13. Meanwhile, in the
ventilation mechanism 10A according to embodiment 2, the
height dimension H1 of a wall 11c is equal to or larger than
the height dimension H2 of a projection 13a (H1≥H2). As in
the above-described embodiment 1, the height dimension H1 of
the wall 11c is larger than the height dimension H3 of the
window 14 (H1>H3). With such a configuration, water can be
even better prevented from being directly splattered on the
window 14 than in the above-described embodiment 1.
[0027] In addition, the wall 11c of the ventilation
mechanism 10A has an annular shape, and there are no such
cuts 12 (see FIG. 1) of the wall 11 as those in embodiment 1.
Accordingly, the inner circumferential surface of the wall
11c is tilted such that water is easily discharged when the
water enters the inner side of the wall 11c. That is, the
wall 11c has an annular tilted surface 111. In addition, the
ventilation mechanism 10A has a bank portion 141 integrated
with the case 2 and provided along the rim of the through
hole 15. The bank portion 141 is located at a lower side of
the window 14 and has a function as a bank to stop water
having entered the inner side of the wall 11c. It is noted25 that embodiment 2 is the same as the above-described1 5
embodiment 1 in that, in a cross section of the ventilation
mechanism 10A, the imaginary straight line L1 obtained by
extending the radially outermost portion of the through hole
coincides with the radially outermost portion of the
projection 13a.
[0028] In addition, the projection 13a has a protruding
portion 132 on the bottom surface 131 thereof, and the
protruding portion 132 is adhered to the water-repellent
filter 17. That is, the water-repellent filter 17 is fixed
to the case 2 at the adhesion portion 171 near the outer rim
and an adhesion portion 172 near the center of the waterrepellent
filter 17. Accordingly, vibration of the waterrepellent
filter 17 is suppressed. It is noted that the area
of the adhesion portion 172 is desirably small in order to
ensure the ventilation area of the water-repellent filter 17.
[0029] According to embodiment 2, improvement in the
waterproof function is further achieved in addition to the
same advantageous effects as those in the above-described
embodiment 1. It is noted that the tilted surface 111 of the
wall 11c, the bank portion 141, the protruding portion 132,
and the like of the ventilation mechanism 10A according to
embodiment 2 can be provided also to the ventilation
mechanism 10 according to embodiment 1.
[0030] Embodiment 3
25 FIG. 8 is a partial cross-sectional view of a
ventilation mechanism of an electronic control device
according to embodiment 3. FIG. 9 is a partial crosssectional
view of molds for molding a case of the electronic
control device according to embodiment 3. A ventilation
5 mechanism 10B according to embodiment 3 is a modification of
the above-described ventilation mechanism 10 according to
embodiment 1 and is the same as the ventilation mechanism 10
in terms of the main configuration. Thus, only the
differences therebetween will be briefly described here.
[0031] In the ventilation mechanism 10B, the height
dimension of a projection 13b is larger than the height
dimension of an annular wall 11d, and the top portion 133 of
the projection 13b extends upward of the wall 11d in the form
eaves. That is, an eaves portion 134 is formed above the15 ventilation path formed by the window 14 and the through hole15. In a cross section of the ventilation mechanism 10B, an
imaginary straight line L2 obtained by extending the radially
outermost portion of the through hole 15 coincides with the
inner circumferential surface 110 of the wall 11d.20 [0032] In addition, the projection 13b has a step 135 near
the center of a side surface thereof in which the window 14
is formed. Thus, the ventilation path is not linear.
Accordingly, the water entry path including the inner
circumferential surface 110 of the wall 11d has a complex25 shape as a labyrinth does, whereby entry of water into the1 7
water-repellent filter 17 can be prevented. In addition, by
providing the step 135, it is possible to reduce the opening
area of the window 14 while ensuring the ventilation area of
the water-repellent filter 17, whereby the waterproof
function and the ventilation function can be ensured. It is
noted that, in the ventilation mechanism 10B, the same
protruding portion 132 as that in the above-described
embodiment 2 may be provided to the bottom surface 131 of the
projection 13b.
[0033] A producing method for the ventilation mechanism
10B according to embodiment 3 will be described with
reference to FIG. 9. In FIG. 9, upper molds 20a and 20b have
such structures as to be separated in the left-right
direction. The upper molds 20a and 20b have window forming
portions 25 for forming the windows 14a and 14b, respectively.
The lower mold 21a has through hole forming portions 22a for
forming the through holes 15a and 15b. A cavity 24 formed by
the upper molds 20a and 20b and the lower mold 21a includes:
a wall forming portion 24a for forming the wall 11d; a
projection forming portion 24b for forming the projection
13b; and the enclosing portion forming portion 24c for
forming the enclosing portion 16.
[0034] Resin is caused to flow into the cavity 24 and
cured, and then the upper molds 20a and 20b are separated to
the left and the right. Consequently, it is possible to form
the ventilation mechanism 10B in which the windows 14 and the
wall 11d are disposed below the eaves portion 134 of the
projection 13b. In addition, the through holes 15 can be
formed by removing the through hole forming portions 22a of
the lower mold 21a in the downward direction in FIG. 9.
[0035] According to embodiment 3, downsizing of the
ventilation mechanism and improvement in the waterproof
function are achieved in addition to the same advantageous
effects as those in the above-described embodiment 1.
Although two windows 14 and two through holes 15 are provided
in the above-described embodiment 1 to embodiment 3, the
number of windows 14 and the number of through holes 15 may
each be one or may each be three or more. In addition, it is
needless to say that the ventilation mechanisms 10, 10A, and
10B according to embodiment 1 to embodiment 3 are not limited
to ventilation mechanisms for electronic control devices 100
but are used as ventilation mechanisms for housings of other
electronic devices.
[0036] Although the disclosure is described above in terms
of various exemplary embodiments and implementations, it
should be understood that the various features, aspects and
functionality described in one or more of the individual
embodiments are not limited in their applicability to the
particular embodiment with which they are described, but
instead can be applied, alone or in various combinations to
one or more of the embodiments of the disclosure. It is
therefore understood that numerous modifications which have
not been exemplified can be devised without departing from
the scope of the specification of the present disclosure.
For example, at least one of the constituent components may
be modified, added, or eliminated. At least one of the
constituent components mentioned in at least one of the
preferred embodiments may be selected and combined with the
constituent components mentioned in another preferred
embodiment.

DESCRIPTION OF THE REFERENCE CHARACTERS
[0037] 1 housing
2 case
2a upper surface
2b inner wall
3 base
4 connector
10, 10A, 10B ventilation mechanism
12 cut
13, 13a, 13b projection
14, 14a, 14b window
15, 15a, 15b through hole
16 enclosing portion
17 water-repellent filter
17a, 17b, 17c region
18 gap
20, 20a, 20b upper mold
21, 21a lower mold
22, 22a through hole forming portion
23 contact surface
24 cavity
24a wall forming portion
24b projection forming portion
24c enclosing portion forming portion
25 window forming portion
100 electronic control device
110 inner circumferential surface
111 tilted surface
131 bottom surface
132 protruding portion
133 top portion
134 eaves portion
20 135 step
141 bank portion
171, 172 adhesion portion

We Claim :
[1] A ventilation mechanism of an electronic device
housing which is a housing accommodating an electronic device,
the ventilation mechanism comprising:
a projection integrated with the housing and
projecting outward of the housing;
a wall integrated with the housing and disposed on
an outer side of the housing so as to enclose the projection;
a window formed in a part of a side surface of the
projection and facing an inner circumferential surface of the
wall;
a through hole forming, together with the window, a
ventilation path which allows communication between an
outside and an inside of the housing; and
a water-repellent filter attached to a region, on
an inner side of the housing, that includes the projection
and the through hole.
[2] The ventilation mechanism of the electronic device
the wall is larger than a height dimension of the window.
[3] The ventilation mechanism of the electronic device
housing according to claim 1 or 2, wherein a height dimension
of the wall is equal to or larger than a height dimension of
the projection.
[4] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 3, wherein a
width dimension of the window is smaller than a width
dimension of the inner circumferential surface of the wall
facing the window.
[5] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 4, wherein an
opening area of the window is smaller than an area of the
inner circumferential surface of the wall facing the window.
[6] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 5, wherein, in a
cross section of the ventilation mechanism, an imaginary
straight line obtained by extending a radially outermost
portion of the through hole coincides with a radially
outermost portion of the projection.
[7] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 6, wherein the
inner circumferential surface of the wall is tilted.
[8] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 7, wherein the
ventilation mechanism further comprises a bank portion
integrated with the housing and provided along a rim of the
through hole.
[9] The ventilation mechanism of the electronic device
housing according to claim 1, wherein
a height dimension of the projection is larger than
a height dimension of the wall, and
a top portion of the projection extends upward of
the wall in a form of eaves.
[10] The ventilation mechanism of the electronic device
housing according to claim 9, wherein, in a cross section of
the ventilation mechanism, an imaginary straight line
obtained by extending a radially outermost portion of the
through hole coincides with the inner circumferential surface
of the wall.
[11] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 10, wherein
the ventilation mechanism further comprises an
annular enclosing portion integrated with the housing and
disposed on an inner side of the housing, and
the water-repellent filter is disposed within the
enclosing portion.
[12] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 11, wherein a gap
is provided between a bottom surface of the projection and
the water-repellent filter.
[13] The ventilation mechanism of the electronic device
housing according to claim 12, wherein
the projection has a protruding portion on the
bottom surface thereof, and
the protruding portion is adhered to the waterrepellent
filter.
[14] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 13, wherein the
projection has a step at the side surface thereof in which
the window is formed.
[15] The ventilation mechanism of the electronic device
housing according to any one of claims 1 to 14, wherein the
wall includes a plurality of walls disposed so as to be apart
from each other.
[16] The ventilation mechanism of the electronic device
housing according to
wall has an annular shape