Note: Descriptions are shown in the official language in which they were submitted.
a4s~zs
mary of the Inventioll
This invention relates to a novel arrangement for mount-
ing electronic circuit boards in the engine compartment oE a
vehicle.
Among the features and objects of the present invention
are to provide an improved mounting arrangement for electronic
circuit boards: which can be easily assembled into and
disassembled from an engine air filter housing; in which the
circuit components are protected from contamination; in which the
components are adequately thermally protected even though con-
tained in the engine compartment; which provides easy connect-
ability to other system components; and which offers other
advantages and benefits as will appear more fully hereinafter. ~-
In one particular aspect the present invention providesin an engine having an induction air intake system including an
air filter housing having a cylindrical side wall, the combina-
tion with said air filter housing of: an electronic circuit
,
board housing containing at least one electronic circuit board
- assembly therein; means mounting said circuit board housing on
the side wall of said air filter housing; and means communica-
ting the interiors of said two housings to provide air circula- -
tion within said circuit board housing when the engine is
operated.
In another particular aspect the present invention pro-
; vides in an engine having an induction air intake system includ-
ing an air filter housing having a cylindrical side wall, the
combination with said air filtex housing of: an electronic
circuit board housing containing an electronic circuit board
assembly therein; means mounting said circuit board housing on
said air filter housing; means communicating the interiors of
said two housings to provide air circulation within said circuit
board housing when the engine is operated, and an electronic
circuit element mounted on said electronic circuit board
~ assembly but disposed in the path of air
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rculation in said circuit board housing.
In yet another particular aspect the present invention
provides in an engine powered vehicle having an induction air
intake system for the engine including an air filter housing having
a cylindrical side wall and an intake snorkel projecting therefrom
and including electronic engine control circuitry, the improvement
comprising: means mounting at least portions of said control
circuitry on a circuit board; a circuit board mounting housing
containing said circuit board therein; means mounting said circuit
board mounting housing on said air filter housing circumferentially
of said snorkel; and means communicating the interiors of said two
housings to provide air circulation within said circuit board
mounting housing when the engine is operated.
In a further particular aspect the present invention
provides in an engine comprising induction air intake structure
including an air filter housing and comprising electronic engine
control circuitry, the improvement comprising: a control circuit
housing adapted to contain electronic control circuitry; means
mounting at least a portion of said electronic engine control
circuitry wlthin said control circuit housing; means mounting said
control circuit houslng on said air filter housing; and means
communicating said two housings to provide air circulation there-
between when the engine is operated.
In yet a further particular aspect the present
invention provides in an engine comprising induction air intake
structure via which air is inducted into the engine and comprising
electronic engine control circuitry, the improvement comprising:
means mounting at least a portion of said engine control circuitry
on a circuit board; a housing within which said circuit board and
said control circuitry portion thereon are contained; and means
communicating said air intake structure and said housing comprising
means via which air can enter said housing from said air intake
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~ structure and means via which air can exit said housing to said
air intake structure.
. Brief Description of the Drawings
The drawings illustrate preferred embodiments of
the present invention according to the best mode presently con-
` templated in carrying out the invention.
Figure 1 is a fragmentary exploded perspective viewof a portion of a typical vehicle engine compartment including a
first embodiment of circuit board housing according to the present
invention.
; Figure 2 is a view showing the interior of the circuit
board housing of Figure 1 by itself with the circuit boards and
thelr receptacles contained therein.
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¦ 1g. 3 is a sect1onal view taken along lines 3-3
in Fig. 2.
Fig. 4 is an enlarged sectional view through one
l of the circuit boards and its receptacle shown in Fig. 2.
¦ Fig. 5 is a sectional view through the other
circuit board and its receptacle shown in Flg. 2.
Fig. 6 is a fragmentary top plan view having portions
broken away illustrating a second embodiment of circuit board
housing according to the present invention.
Fig. 7 is a fragmentary side elevational view of
Fig. 6.
Fig. 8 is a fragmentary sectional view taken in the
direction of arrows 8-8 in Fig. 6.
Fig. 9 is a fragmentary end view of Fig. 8.
Fig. 10 is a sectional view taken in the direction
of arrows 10 10 in Fig. 6.
Fig. 11 is a plan view of the interior of the
upper half of the circuit board housing of Fig. 6 shown by itself.
Fig. 12 is a sectionai view taken in the direction
2Q of arrows 12-12 in Fig. 11.
Fig, 13 is a plan view of the interior of the
lower half o~ the circuit board housing shown ln Fig. 6.
Fig. 14 is a fragmentary view taken in the direction
of arrow 14 in Flg. 13.
Fig. 15 is a sectional view taken through one of
the electrical connector pl~gs lncluded in the arrangement of
ig. 6 and is taken in the direction of arrows 15-15 in Fig. 16.
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¦ Fig. 16 is a plan view Or the connector plug
¦ shown in Fig. 15.
¦ Fig. 17 is a side view Or the connector plug
¦ in Fig. 16.
; 5 ¦ Fig. 18 is a sectional view through the other
connector plug included in the arrangemen~ of Flg. 6 and ls
taken in the directlon of arrows 18-18 in Fig. 19.
¦ Fig. 19 is a plan vlew of the connector plug
of Fig. 18.
Fig, 20 isa side view of the connector plug
shown in Fig. 19.
Fig. 21 is a fragmentary sectional view in the
direction of arrows 21-21 in Fig. 6.
, Fig. 22 is a side elevational view showing the
r
inn~rfaao~of the circuit board housing.
Description of the Preferred Embodiments
In Fig. l there is shown a portion o~ a typical
vehicle engine compartment including an engine 10, a carburetor
12, an air filter housing 14, an ignition coil 16, and a
distributor 18. The engine further includes an electronic control
; system for example, an engine spark timing controller which
controls the timing of the ignition spark in relation to certain
; control inputs. For example, one input may be the throttle
positlon as monitored by a throttle position transducer 20 and
,~ another may be the engine manifold vacuum as monitored by a
; vaouum t sducer 22.
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The present invention ls concerned with a novel
¦ mounting arrangement for mounting the electronic circultry
¦ Or the electronic control system in the engine compartment.
¦ More specifically, the present invention, in a first embodiment
¦ as shown in Figs. 1 through 5, provides a circuit board housing
¦ 24 which removably mounts on air cleaner housing 14. Details of
¦ housing 24 are shown in Figs. 1, 2 and 3. Houslng 24 pre-
¦ ferably is a molded plastic element suitable for use with the
higher temperatures which are generally encounte~red in the
B l engine ccmpartment; for example, ~1~6S ~ d~nylon or glass-
fllled polyester are suitable. Housing 24 is of generally
concave shape with the inner face thereof facing radially
l inwardly of air filter housing 14. Air fllter housing 14
¦ is generally conventional; however, in accordance with the
principles of the present invention the side wall of housing 14 i
provided with one or more air circulation openings over which
circuit board housing 24 is disposed. Such openings are
illustratively shown at 26 and 28 in Fig. 3. Attachment means fo
attaching circuit board housing 24 to air cleaner housing 14
are provided in the form of outwardly turned tabs 30 and 32 on th
I side wall of air filter housing 14. Circuit board housing 24!, iS provided with a radially outer wall 34 which extends be-
, tween the points at which it attaches to air filter housing 14.
This outer wall 34 is parallel to the axis of the air filter hous
ing but is sp~ced radially outwardly from the nominal diameter
the a f1lter housing. Circuit board houslng 24 further
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includes a top wall 36 and a bottom wall 38 which proJect
¦ radially inwardly from the outer wall 34. Both top and bottom
¦ walls 36, 38 have their inner peripher~es generally circularly
contoured to match the contour of the side wall of houslng 14
¦ so that the circuit board housing seats on the air filter
hous~ng.
Housing 24 removably mounts on housing 14 in the
following fashion, Tab 30 is provided with a slot 40 into which
the free end of a r1ght angle pro~ecting flange 42 on one end o~
housing 24 may be inserted. With-the houslng 24 appropriately
oriented to permit insertion of the free end of ed8e 42 into slot
40, the edge is inserted into the 810t, and housing 24 is piv~ted
thereabout to bring the housing to the posltion shown in Fig. 3.
A pair o~ holes are provided in tab 32 and matching clearance -
holes in the Juxtaposed edge 44 of housing 24 so that attachment
screws 46 may~be inserted through the clearance holes to engage
~ ` the holes in tab 32 and secure the attachment. With housing 24
;~ secured to housing 14 it will be noted that the free edge 42
interlocks behind tab 30.
A pair of electronlc circuit board assemblies 48
and 50 are mounted interiorly of housing 24 within a pair of
sheet metal receptacles 52 and 54,respectively. Greater details
of the two circuit board assemblies 48, 50 and their respective
receptacles 52, 54 are shown in Figs. 4 and 5. The circuit board
f each circuit board assembly is o~ rectangular shape and contain s
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thereon a large number of the electronic circuit components
forming electronic circuits of the engine control system.
Each sheet metal receptacle has a rectangular shape similar
to that of the corresponding circuit board assembly. Each
circuit board assembly also contains an electrical connector
plug which mates with a mating connector plug (not shown in
Figs. 2-5) to effect electrical connection of the circuits
on the circuit board assembly with components of the system
which are external to the circuit board assemblies. The
connector plug for circuit board assembly 48 is designated
by the reference numeral 56 and that for circuit board
assembly 50 by the reference numeral 58.
Each circuit board assembly 48, 50 and its corres-
ponding receptacle form an individual unit which removably
mounts on wall 34 of housing 24. The circuit board ~ -
assemblies are potted in their respective receptacles, and
the receptacles are provided with apertured side flanges, or
tabs, 60 via which the units attach to wall 34 by means of
attaching screws 62. Clearance holes 64, 66 are provided in
wall 34 for connector plug 56, 58 respectively, and annular
gaskets 68, 70 seal between each connector plug and its
clearance hole 64, 66.
Each circuit board assembly 48, 50 mounts within
its receptacle 52, 54 in the following fashion. There are
provided in the radially inner wall 52a, 54a of each
receptacle several localized indentations illustratively
indicated by the reference numeral 72. Each receptacle is
oriented with its wall 52a, 54a horizontal and its interior
facing up. The circuit board assemblies are positioned
within their receptacles to rest on in-
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dentations 72, thereby providing a clearance space between each
board and the wall 52a, s4a of itg receptacle. If necessary, one
or more bendable retention tabs, such ag 74, may be provided on
l a receptacle to assist in holding and locating the clrcult board.
¦ A suitable potting compound is then poured into the receptacle
to a desired rill level 76 suf~iclent to cover the circuit
board and virtually all the individual electronic circuit
components thereon. Because-i~dentatlons 72 are only localized
and because the overall dimensiong of each circuit board are
slightly less than those of lts receptacle, the potting compound
flows around the edges of the board to substantially flll the
space between the board and the receptacle wall. It may be found
desirable to facilitate filling by provlding holes in the olrcuit
board. Once the receptacle has been filled, the pottlng com-
pound is allowed to cure into a rubbery-llke encapsulant.
Electrical terminals, such as 78 may protrude above the fill leve
76 to provide for connection intern~Y of housing 24, for
example between the two circuit boards. Other devices may mount
on the units, for example a heat sink 80 for a power transistor
82 usedin the circuitry associated with board 50.
It is contemplated that other devices may mount on
housing 24, for example vacuum transducer 22, which mounts on
wall 34 ~etween the two circuit board receptacles. Electrical
terminals 84 for'transducer 22 are interior of housing 24 and
may connect by lead wires with selected terminals 78. A nipple
86 to which manifold vacuum is conducted is located exteriorly
so that a vacuum hose may be inserted thereon.
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¦ An especially good pottlng materia~ ~or the units is
G l silicone rubber, such as Dow-Corning ~'Sylgard~' or General
¦ Electric l'RTV627". This material posses physical properties
¦ which are especially desirable with the present invention.
¦ For example, the material exhibits excellent dielectric
¦ characteristicsj very low thermal conductivity, remains
l reasonably pliable at very low temperatures and retains its
¦ shape at very high temperatures. Because of its low thermal
conductivity, the potting material thermally insulates those
components which it covers. Because o~ the extremely low
power dissipation of most ofthe electrical circult components
mounted on the circuit boards, these components can be completely
covered by potting material. However, i~ a component dissipates
a larger a~ount o~ heat, it may be desirable to expose
same to the interior of housing 24. With the engine operating,
the present invention a~fords a certain air circulation within
housing 24 caused by the induction ef~ect o~ air drawn lnto
the carburetor through the air filter housing. Even though
the snorkel 88, via which air enters the air rllter housin~
is located essentially diametrically opposite circult board
housing 24, the provision of air clrculation cpenings 26, 28
exposes the interior of housing 24 to the interior air filter
housing 14 so that air flow and air turbulence within housing
14 gznerate air currents within housing 24 across the receptacle
and circuit board assembly units. Thus, in the case o~
transistor 82 and its heat sink 80, there is provided a certain
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convective cooling. In order to maintain the temperature o~ the
intake air as close to ambient as possible, lt may be beneficial
to connect air intake ho~e 90 to snorkel 88 80 that air can be
gathered at a locatlon remove rrom the englne comp~rtment.
If desired~ either or both the hose 90 and the air filter housing
14 may be covered with insulatlon to further mln~mize temperature
rise in the induction air. With the lnvention it is possible
to accurately sense the amblent air temperature by means of a
temperature responsive element such a~ a thermistor mounted ln
circuit on one Or the circult boards, but proJecting from its
receptacle to be disposed in the air withln the houslng. It
may also be desirable to provide an air scoop or diverter at
one of the air circulation openings to promote air circulatlon
within the housing. '
The second embodiment of the present inventlon shown ¦
in Figs. 6 through 22 possesses a number of features which are
dlfferent from those of the first embodiment. The second
embodiment comp,rises a circult board housing lOO which is of
two-piece construction. Specifically, h'ousing 100 comprises a
molded plastic element 102 forming the upper half of the housing
and a second molded plastic element 104 forming the lower hal~
of the houslng. The two houslng elements are detachably
secured together along their mating surfaces by means of a
plurality of attachment screws 106 which extend through holes in
bosses formed at intervals around the two elemLnts.
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Detalls of the upper and lower housing elements 102,
lO4 are best shown in Figs. 11 through 14 whlch illustrate the
two houslng elements by themselves. As can be seen in Figs.
¦ 11 and 12,upper housing element 102 comprises a rectangularly
5 1 shaped circuit-board-receiving pocket 108. The mating surface
¦ 110 of element 10~ which mates with lower houslng element
¦ 104 lies in a flat plane WhiCh i8 diæposed horizontally when
housing 100 is mounted on air filter housing 14. Similarly,
I lower housing element 104 has a rectangularly shaped circuit-
board-recelving pocket 112 and a mQting ~urrace 114, which mates
with surface 110 when the two elements 102, 104 are assembled
together. HoweverJ the two mating surraces 110, 114 are not
necessarily conti~ous-throughout, In order to provide a
seal between the upper and lower~housing elements around three
sldes of the two clrcuit-board-recelving pocke~ts 108, 112,
there is provided on element 102 a raised bead 116 on surface
110 extending around three sideQ Or pocket 108. There is also
provided in element 104 a complementary recess 118 in which bead
116 lodges when the two housing halves are assembled. By making
the height Or bead 116 slightly greater than the depth Or
recess 118 throughout their respective lengths, a continuous
sealing contact is erfected between the two when assembled.
Accordingly, it will be appreciated that the mating surfaces 110,
112 are not necessarily in continuous contact with each other
throughout. ~his feature has the advantage of eliminating
the need for a separate sealing gasket between the two~housing
halves.
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Considering Figs. 6 and 11 through 14 in greater
. ¦ detail, one will observe that housing 100 is further endowed
with an intake alr scoop.l20 having an intake opening 122 and
an air discharge outlet 124 which is spaced circumferentially of
1 scoop 120. The top wall of air scoop 120 is pro~ided by the
~ ¦ triangularly shaped projection 126 in element 102 whlle
; ¦ the remainder of the air scoop is formed in lower element 104.
. ¦ Similarly, the top of discharge outlet 124 is provided by the
: I portion 128 of element 102 and the remainder thereof ln element
l 104. With the two housing elements assembled together, and mount d
l on air filter housing l4 as shown in Fig. 6, induction air
I ~c~ s~o~k~
B entering ~ho~u~h~the air cleaner ~e~e~is drawn in the directio
of the arrows into scoop 120, passing through the interior
of housing 100 and discharging at outlet 124. Air flow through
the housing may be promoted by the location of an upstanding
diverter 130 ad~acent the intake opening 122 of scoop 120.
: ` As will become apparent, the air flow circulation through
housing 100 provides effective cooling for the electronic
circuit components contained within the housing.
Looking now at Figs. 10 and 21, along with Figs. 11-1 ,
a first electronic circuit board assembly 132, containing .
a number of electronic circuits thereon (which are not
j illustrated in the drawing for the sake Or clarity), is contained
within pocket 108 while a second electronic circuit board
, 25 assembly 134 is contained within pocket 112. Desirably, each
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circuit board is potted within its resRectiye housing element
by means of suitable pott-ing material. An advantage of the -
instant arrangement concerns assembly of each circuit board
assembly into its corresponding housing element which is as
follows. With the interior of the housing element pocket
facing upwardly, the appropriate circuit board as.sembly is
placed within its pocket so that the circuit board itself
rests upon one or more individual ledges 136 which are pro-
vided in the pocket. For the first circuit board assembly,
there are provided four ledges 136 (Fig. 11~ within pocket
108, and these ledges are formed integrally with element 102.
A feature is to provide one or more locating pins in element
102 which facilitate the correct location of the circuit
board assembly within the pocket and which can prevent the
circuit board assembly from being oriented 180~ from the -
position which it shou]d occupy. For example, element 102
is provided with a pair of integral locating pins 138 which
project upwardly from raised bosses 140 formed within pocket
108. The circuit board of circuit board assembly 132 is
provided with a matching hole pattern to permit the circuit
board assembly to be located on pins 138 so that the circuit
board itself comes to rest on the ledges 136 and the bosses
140. With the circuit board thus located, the locating pins
138 protrude substantially above the surface of the circuit
board and may be deformed, as by heat staking, into a blob
(as shown in Fig. 10) which retains the circuit board assembly
in the desired position. Pottin~ material may now be poured
into the pocket to a desired fill level 141 after which the
material is allowed to cure into a rubbery-like encapsulant
for the circuit board and most of the components thereon.
As mentioned in connection with the first
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ernbodiment, filling is racilitated by providing one or more
openin~s in the clrcuit board to permit the potting material
to flow around and beneath the circuit board to avoid unfilled
pockets upon curing.
For the lower circuit board assembly 134, which is contained
within element 104, there is provided only a single ledge 136
and a single locating pin 138 and boss 140, both of which are
located toward the left hand side of pocket 112 as viewed in
Fig. 13. The right hand side of the circuit board 134 is
both located and supported by virtue of an electrical connector
plug assembly 142. As best shown in Figs. 15 and 21, circuit
board assembly 134 has the connector plug 142 mounted thereon
so that the connector plug extends from the c~rcuit board
downwardly through a rectangular opening 144 formed in the lower'
wall of housing element 104 within pocket 112. The design of
the plastic shell of connector plug assembly 142 is;~such that
when the circuit board assembly is being assembled into housing
element 104 the plug assembly passes through opening 144 camming
a retention tab 146 on the plug shell out Or the way. As the
circuit board assembly locates in the intended positlon, the re-
tention tab 146 clears the wall of the housing and the inherent
resiliency thereof brings the tab into interlocking engagement
w~th the housing as shown in Fig. 15. In order to seal around
opening 144 between the connectoF plug shell and the housing wall
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¦ a cornpressible sealing gasket 148 ls disposed around the shell
l to be compressed between the housing wall and a back-up flange
¦ 150 formed around the shell. The illustrated connector plug
¦ contains four electrical terminal pins 152 which are intended
¦ to effect electrical connection of selected circults on the
¦ circuit board assembly with mating terminal pins in a matlng
B l connector plug which mates with plug 142 to~a~rying the
circuits associated wlth the terminal plns ~o electrical devices
located remotely from houslng 100. With the lower circuit board
assembly 134 located within pocket 112, locating pin 138 may be
deformed and then potting material may be poured into the
pocket to a desired ~ill level 154.
The upper circuit board assembly 132 is provided
with an eight terminal pin connector plug assembly 156
which is similar to connector plug assembly 142. However, unlike
connector plug 142, connector plug 156 does not pass through an
openlng in lts own housing. Rather, connector plug 156 pro~ects
in the opposite directlon relative to its mountlng pocket. The
connector plug 156 is so located and the two halves of the housin~
are so designed that when the two housing halves are assembled
together~ the connector plug 156 pro~ects through a matching
opening 158 in the opposite housing halr. This can be seen in
detall in Figure 18 where the shell of connector plug assembly
156 passes through opening 158 and a sealing gasket 160 seals
bet-~en two 1A the same manner as dld the seal ~8 for the oth t
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connector plug with respect to its housing. It will be
observed that the shell of connector plug 156 lacks any
type of interlocking retention tab such as 146 for the
connector plug 142. Indeed, it is desirable that the shell
of connector plug assembly 156 not have any such retention
tab so that the two halves of the housing may be readily
separated from each other should such disassembly be
necessary. By providing such an arrangement, connection of
mating connector plugs is facilitated since both are adjacent.
Furthermore, the arrangement is vertically compact which is
desirable in a vehicle engine compartment.
Where the circuit configuration is such that
electrical connections are requi;red between the t~o circuit
board assemblies such may be readily efEected by providing
terminal pins such as indicated at 162 (Fig. 10~ on one of
the circuit boards which project above the leyel of the
potting material. Leadwires from the other circuit board
may then be soldered to the terminal pins 162 at a level
above the potting material. Where a circuit element dissi-
pates a large amount of heat it is desirable to mount same in
the path of air flow through the housing. An example is shown
in Fig. 2]. wherein a power transistor 164 and associated heat
sink 166 are mounted on upper circuit board assembly 132.
The transistor 164 is attached by means of attachment screws
168 passing through the circuit board to engage tapped holes
in the mounting base of the transistor, the heat sink 165 and
an insulating spacer 170 being sandwiched therebetween. Heat -
generated within the power transistor is dissipated via the
transistor casing and heat sink to the circulating air passing
through the housing. In this way the maximum temperature of
the transistor is maintained within an acceptable limit. Like-
wise, as mentioned in connection with the first embodiment,
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the invention permits the measu~emellt of a~)~ient temperature
air by means of a temperature sensing element electrically
connected in circuit with one of the circuit boards but being
disposed above the level of potting material to be exposed to
the ambient air passing througll the circuit board housing.
By way of examp]e, the thermistor 172 in Fig. 21 can sense
the temperature of the air and is preferably located upstream
of the transistor and heat sink so as to not be influenced by
any temperature rise in the air due to the heat dissipation by
the transistor and heat sink.
Housing 100 is also designed to accommodate a
transducer like the vacuum transducer shown in the first
embodiment. However, the arrangément of the second embodiment
in this regard offers important advantages over the arrange-
ment of the first embodiment. As best seen in ~igs. 6
through 9, a transducer 174 mounts on housing 100 by being
mechanically trapped between the two housing halves. ~By way
oi example, transducer 174 may be a vacuum-actuated variable
inductance type as disclosed and claimed in copending appli-
cation Serial No. 243,475, filing date January 13, 1976. This
type of transducer comprises a generally cylindrical vacuum
actuator portion 176 and a smaller cylindrical coil portion
178. The lower housing element 104 immediately adjacent the
left hand side of pocket 112 as viewed in Fig. 13 contains a
receptacle 180 into which the transducer 174 is inserted.
; ~eceptacle 180 is generally semi-cylindrically shaped and com-
prises an inner portion 182 whlch is adapted to receive the
coil portion 178 of the transducer, and an enlarged outer
portion 184 which is adapted to accommodate the larger diameter
of the vacuum actuator portion 176 of the transducer. A groove
186 is formed in the outer portion 184 and receives the lowe~
portion of a flange 188 provided on the transducer adjacent ~he
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juncture of the Yacuum actuator portion and the coil portion.
As best seen in Fig. 14, the cross section of receptacle 180,
and its severRl portions 182, 184, and 186, is such that the
surfaces thereof lie on respective truly semi-cylindrical
surfaces about and below an axial centerline 189. Above the
centerline 189, the respective surface portions continue as
spaced parallel walls extending upwardly from the truly semi-
cylindrical portions. Hence, the receptacle 180 and its
portions 182, 184 and 186 may be considered as U-shaped as
viewed in ~'ig. 14. The flange 188 on the transducer has its
lower portion designed to complement the U-shaped groove 186.
This shape can be seen in Fig. 9. This construction permits
transducer 174 to be readily inserted into receptacle 180 so
that the U-shaped flange 188 fits within and registers with
the U-shaped groove 186. When so inserted the transducer is
correctly located both circumferentially and axially, and
relative rotation between housing element 104 and the trans-
! ducer 174 about the centerline 189 is precluded. Thus, the
transducer mounting arrangemellt advRntageously provides a self-
locating, anti-rotation feature, and furthermore eliminates
the need for any separate mechRnicRl fasteners. The upper
housing element 102 is designed with a circularly contoured
segment 190 and a circularly contoured groove 192 formed
therein to engage the circularly contoured upper portion of
the transducer flange 188 when the two housing halves are --
assembled. It will be observed that when the two housing
halves are assembled, the portions of the surface 110
immediately adjacent the ends of groove 192 overlie the tops of
the lower U-shaped portions of flange 188 thereby also
precluding rotation of the trRnsducer. Two electrical termi-
nals 194, 196 at the inner end of the transducer, are connect-
ed with the lower circuit board assem~]y 13~ by means of lead
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wires 19~, 200 ~hich lead from the termina~s througll suitable
passageways formed in housing element 104. This transducer
mounting and connection arrangement enhances assembly and
serviceability. Also, the flange and groove seals between the
housing and the transducer to prevent the intrusion of contam-
inants.
In the assembled unit it is desirable to adhere a
sealing gasket 202 on the concave inner face of housing 100 as
shown in Fig. 22. The sealing gasket includes suitable cut-
outs 204, 206 for the air scoop and the air discharge outlet
respectively as well as cutaways 20~ for the attaching holes
via which the housing is attached to the air cleaner housing
14. As can be seen in Fig. 6, housing 100 is attached to air
cleaner housing 14 by means of attachment screws 210 which
pass through suitable holes in the side wall of the air filter
housing to threadly engage matching holes provided in housing -
100. This permits the housing to be conveniently attached to
and removed from the air filter housing. With the provision
of the sealing gasket and the design of the two housing
elements, the interior of the unit is adequately sealed so
that the only exterior communication is via the air inlet and
outlet openings.
-19-
mjp/
.
