Note: Descriptions are shown in the official language in which they were submitted.
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:[NTAKE SILENCER SYSTEM
RACK~.F~OUND OF T~ INV~NTION
1. FTF.T~n OF T~ INV~TION
The present invention relates to an intake silencer
system including an.intake duct which communicates at opposite
ends thereof with the atmospheric air and an engine,
respectively, and whose intermediate portion opens into an
intake silencing chamber.
2. D~.~CRIPTTON OF T]~ RF.T.~T~.~ A~T
An intake silencer system is known, for example, from
Japanese Patent AppLication Laid-open No.8-158965. As shown
in Fig.9, in theknown intake silencersystem, afirstsilencing
chamber 02 and a second silencing chamber 03 are defined in a
case 01by divisiono.Ethe inside of the case 01. A first intake
duct 04 communicating with an engine and a second intake duct
05 communicating the atmospheric air are opposed to each other
within the first silencing chamber 02. The second intake duct
05 communicates with.the second silencing chamber 03 through
a communication pipe 06. In this manner, a silencing function
is obtained by the resonance effect of the first and second
silencing chambers 02 and 03.
The above known system suffers from the following
problem: Each of the first and second silencing chambers 02
and 03 exhibits a silencing effect only in a single frequency
band. For this reason, to ensure that the silencing effect is
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exhibited in awiderfrequency range, itisnecessarytofurther
increase the number of the silencing chambers, or to add a side
branch. This is complicated and increases the size of the
structure of an i,ntake silencer system, resulting in an
increased cost. Particularly, if the intake silencer system
having the complicated structure and the large size is to be
disposed in a narrow engine room, the following problems are
encountered: a required large space hinders the disposition
of other auxiliaries, and the workability of attachment and
detachment of the intake silencer system is reduced due to the
interference with other members.
Sl~ ~Y OF T~F INV~NTION
Accordingly,iLt is an object of the present invention to
provideanintakesilencersystemwhichiscapableofexhibiting
asilencingeffectoverawidefrequencyrangewhilemaintaining
a simple and compact structure, and moreover, which can be
easily disposed in a narrow space such as an engine room in an
automobile.
To achieve the above object, according to a first aspect
and feature of the present invention, there is provided an
intake silencer system comprising an intake duct which
communicates at opposite ends thereof with the atmospheric air
and an engine, respectively, and whose intermediate portion
opens into an intake: silencing chamber. The intake silencer
system further includes a plurality of subsidiary silencing
chambers which are deflned within the intake silencing chamber
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by integrally connecting the opposed wall surfaces of the intake
silencing chamber to each other with a plurality of ribs, the
subsidiary silencing chambers being closed at one end thereof
and opened at the ot]her end directly into the intake silencing
chamber. The silencing chambers have different resonance
frequencies.
With the above; arrangement, the plurality of subsidiary
silencing chambers h.~ving the different resonance frequencies,
can be formed in a simple and compact structure in which the
opposed wall surfaces of the intake silencing chamber are only
integrally connected to each other by the plurality of ribs.
Therefore, a silencing effect over a wide frequency range can
be obtained by the resonance effect of each of the subsidiary
silencing chambers, each functioning as a side branch.
Moreover, the rigidity of the wall surfaces of the intake
silencing chamber is enhanced by the plurality of ribs and hence,
it is possible to effectively inhibit the generation of a
radiated sound due t:o the vibrstion of the wall surfaces.
If some of the wall surfaces have an area larger than that
of other wall surfaces of the intake silencing chamber, the wall
surface rigidity which would have been decreased because of its
larger area can be rei.nforced by the ribs to further effectively
inhibit the generation of the radiated sound, and also the size
of the ribs can be m.alntained to the minimum.
The intake sil~encing chamber may comprise a first case
half and a second ca~;e half with mating faces thereof coupled
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to each other to clamp the intake duct, and the plurality of
subsidiary silencing chambers defined in the first case half
may open toward thernating faces. With the above arrangement,
when the first case half is formed in a mold, the plurality of
subsidiary silencing chambers can be formed simultaneously,
leading to an enhanced productivity.
The plurality of subsidiary silencing chambers are
disposed on one side of the intake silencing chamber and the
intakeductisdisposedontheothersideofthe intakesilencing
chamber, in a horizontal direction, respectively. With the
above arrangement, the intake duct is prevented from
interfering with the ribs and hence, the size of the ribs is
not limited, leading to an increased freedom in determining of
the sizes and shapes of the subsidiary silencing chambers.
According to a second aspect and feature of the present
invention, an intake silencer system mounted in a vehicle and
comprising an intake duct which communicates at opposite ends
thereof with the atmospheric air and an engine, respectively,
and whose intermediate portion opens into an intake silencing
chamber, wherein at least a portion of the intake silencing
chamber is formed by a slant surface inclined with respect to
a center plane of a vehicle body and extending along a wall
surface of the vehic:le body, and a plurality of subsidiary
silencing chambers havlng different resonance frequencies are
defined within the intake silencing chamber by extending a
plurality of ribs formed integrally with the slant surface in
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parallel to one another toward the intake duct.
With the above arrangement, it is possible to prevent a
dead space from being produced between the intake silencing
chamber and the wall surface of the vehicle body by extending
the slant surface of the intake silencing chamber along the wall
surface of the vehicle body to effectively utilize a space.
Moreover, the slant surface enables the plurality of subsidiary
silencing chambers to have different sizes and shapes and
different resonance frequencies. Therefore, it is possible to
obtain a silencing effect over a wider frequency range by a
resonance effect of each of the subsidiary silencing chambers
each functioning as a side branch. Additionally, the plurality
of ribs enhance the rigidity of the intake silencing chamber
and hence, it is poss:ible to effectively inhibit the generation
of a radiated sound due to the vibration.
The plurality of subsidiary silencing chambers are
disposed on one side of the intake silencing chamber and the
intake duct is disposed on the other side of the intake silencing
chamber, in a horizontal direction, and tip ends of the
plurality of ribs are trued up in a longitudinal direction of
the vehicle body. With the above arrangement, the interference
of the intake duct with the ribs is prevented and hence, the
size of the ribs is not limited, leading to an increased freedom
in determining the sizes and shapes of the subsidiary silencing
chambers. Moreover, the wall surface for forming the ribs in
the intake silencing chamber can be ensured, enhancing the
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rigidity of the int~ke silencing chamber.
In addition, :if the shape of the cross section of the
intake duct is an e:Lliptic shape with a short diameter in a
direction of extens:Lon of the ribs, the interference of the
intake duct with the ribs is further effectively prevented,
leading to a further increased freedom in determining the sizes
and shapes of the subsidiary silencing chambers.
RRT~F O~CRIPTTON OF T~ D~WTNGS
The above and other objects, features and advantages of
the invention will become apparent from the following
description of the pceferred embodiment taken in conjunction
with the accompanying drawings.
Figs.l to 7 show a first embodiment of the present
invention, wherein
Fig.l is a side view of a front portion of a vehicle body
of an automobile having an intake silencer system mounted
therein;
Fig.2 is aview-takenin adlrectionofan arrow 2inFig.l;
Fig.3 is a sectional view taken along a line 3-3 in Fig.l;
Fig.4 is a perspective view of the entire intake silencer
system;
Fig.5 is a view taken along a line 5-5 in Fig.4;
Fig.6 is a sectional view taken along a line 6-6 in Fig.5;
Fig.7 is a graph for explaining a silencing effect;
Fig.8 is aviewsimilartoFig.6,butaccordingto asecond
embodiment of the present invention; and
70488-123
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Fig.9 is a view showing the prior art intake silencer
system.
D~TATT~n D~SClPTION OF T~ PR~FF.RRF.~ F.~R~DIM~T~
The present invention will now be described by way of
embodiments with reference to the accompanying drawings.
AsshowninFigs.lto3, arightsideframe22constituting
a vehicle body frame according to a first embodiment of the
present invention is disposed in a longitudinal direction of
a vehicle body of an automobile at a front and right portion
of an engine room 21 provided at a front portion of the vehicle
body. As can be seen from Fig.2, a fender 23 constituting a
wall surface of the vehicle body according to the first
embodiment of the present invention is disposed on the right
of the sideframe 22,and an intakesilencersystem Ris disposed
between a left side of the fender 23 and a right side of the
side frame 22. The intake silencer system R comprises a case
14 which is made of a synthetic resin. The case 14 comprises
a right first case half 11 and a left second case half 12
integrally coupled to each other at mating faces 13 extending
in a vertical direction. An intake duct 15 which is made in
a J-shape of a synthetlc resin, is clamped between the mating
faces 13 of the first case half 11 and the second case half 12.
Mounting brackets 12lo and 1211 are integrally formed at
a front end and a rear end of the second case half 12,
respectively, and fastened to the side frame 22 by bolts 24,
24. A rubber cushion 25 is mounted at a central portion of the
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left side of the second case half lZ to abut against a right
sideof aplatemember221pendingdownwardsfrom afrontportion
of the side frame 22, whereby the leftward and rightward
deflections of the case 14 are limited. As can be seen from
Fig.2, the intake silencing system R is supported to protrude
rightwards from the side frame 22 by fastening the second case
half 12 to the side frame 22, but the intake duct 15 heavy in
weightisdisposedatalocationnearthesideframe22andhence,
the rigidity of supporting of the intake silencer system R is
enhanced. A battery 26 is supported at a front and left portion
of the side frame 2:2.
As can be seen from Fig.2, a front portion of the fender
23 in a direction of- the vehicle body as view in a plane is
inclined in a direction toward a center plane P of the vehicle
body, and a right case sidewall 118 of the first case half 11
is formed so that it is inclined along an inner surface of the
fender 23. As a result, the inner surface of the fender 23 and
the case sidewall ll,~of the first case half 11 are opposed to
each other though a small gap a. By the fact that the case
sidewall 118 extends along the fender 23 in the above manner,
a dead space can be prevented from being produced within the
narrow engine room 21 to effectively utilize a space.
A recess 11l3 ~see Figs.2 and 4) is defined at a front
lower portion of the f~rst case half 11, and a turning signal
lamp 27 mounted at a right end of a front bumper (not shown)
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is accommodated in the recess 11l3.
A pair of mounting brackets 281 and 282 are mounted at
front and rear portions of an air cleaner 28 and fixed to upper
ends of a pair of front and rear stays 29 and 30 risen on an
uppersurfaceofthesideframe22bybolts31,31,respectively.
As a result, the air cleaner 28 is supported at a location above
the side frame 22 and between a rear portion of the right-side
intake silencer sysl:em R and a rear portion of the left-side
battery 26. At this time, the air cleaner 28 is disposed in
an inclined manner, so that its upper surface is parallel to
a bonnet 32 to prevent the interference with the bonnet 32
declining forward (see Fig.l).
An intake introducing duct 33 extending upwards toward
a lower surface of t:he bonnet 32 is connected to an air inlet
155 of the intake duct 15 protruding from an upper surface of
the case 14, and an air outlet 156 of the intake duct 15
protruding from the upper surface of the case 14 is connected
directly to an air inlet 283 protruding from a lower surface
of the air cleaner 28.. An air outlet 285is provided in an upper
portion of the air cleaner 28, i.e., on an opposite side from
the air inlet 283 with an element 284 interposed between the
air outlet 285 and the air inlet 283, and is connected to the
engine (not shown) through an air flow tube 34.
The structure of the intake silencer system R will be
described below in detail with reference to Figs.3 to 6.
The first case half 11 has a volume larger than that of
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the second case half 12 and includes a wedge-shaped recess 16
which is defined at a location spaced one third of the way down
from an upper surface of the first case half 11 and which extends
toward the mating face 13. A first partition wall 11l extends
horizontally from t:he tip end of the wedge-shaped recess 16
toward the mating face 13. The tip end of the first partition
wall 111 is coupled to a tip end of a second partition wall 12
extending horizonta.lly from an inner surface of the second case
half 12 toward the mating face 13. As a result, a first resonant
chamber 17 forming an intake silencing chamber of the present
invention is defined between lower-side case upper walls 112
and 122 and a lower-slde recess upper wall 16l as well as the
first and second partition walls 11l and 12l, and a second
resonant chamber 18 is defined between lower-side case lower
walls 113 and 123 and an upper-side recess lower wall 162 as well
as the first and second partition walls 111 and 121.
A pair of annular projections 151 and 152 are formed around
an outer periphery of an upper portion of the intake duct 15
and interposed between a pair of notches 114 and 115 defined
in the case upper wa:Ll 112 of the first case half 11 and a pair
of notches 124 and 125 defined in the case upper wall 122 of the
second case half 12 (see Figs.4 and S). A pair of annular
recesses 153 and 154 are defined around an outer periphery of
a lower portion of the intake duct 15 and interposed between
a pair of notches 116 and 11~ defined in the first partition
wall 111 of the first case half 11 and a pair of notches 126
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and 127 defined in the second partition wall 121 of the second
case half 12 (see Figs.5 and 6). The intake duct 15 is firmly
clamped between the first case half 11 and the second case half
12, and the air inlet 155and the air outlet 156protrude upwards
from the case upper walls llz and 122-
The J-shaped i.ntake duct 15 has portions located within
the first resonant chamber 17, connected to each other by a
connecting wall 157, and a slit-shaped opening 158 is formed
therein for permitting the inside of the intake duct 15 to
communicate with the~inside of the first resonant chamber 17,
the opening 158 being formed by cutting a portion near the air
outlet 156 up to a location reaching the connecting wall 157.
The intake ductl5includes acommunicationpipe 159at aportion
located within the second resonant chamber 18, so that the
inside of the intake duct 15 communicates with the inside of
the second resonant,,hamber 18 through the communication pipe
159
Three ribs 119, lllo and 111l are formed in parallel to
one another within the first resonant chamber17. The ribs 119,
lllOandllllareconnectedtothecaseupperwalls 112,therecess
upper wall 161 and a case sidewall 118 and extend toward the
mating faces 13. Four subsidiary silencing chambers l9a, l9b,
l9c and l9d are defi:ned in a divided manner within the first
resonant chamber 17 and open toward the mating faces 13. The
sizes and shapes of the four subsidiary silencing chambers l9a,
l9b, l9c and l9d are different from one another, so that they
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each have different resonance frequencies. A plurality of ribs
112 are provided in the wedge-shaped recess 16 of the first case
half 11 to connect the recess upper wall 161 and the recess lower
wall 162 to each other.
As can be seen from Figs.4 and 5, the second case half
12 has two water scupper bores 128 and 129 for d.ischarging water
from the first and second resonant chambers 17 and 18. The water
scupper bore 128 in the first resonant chamber 17 is provided
in a front portion o:E the first resonant chamber 17 and hence,
a sufficient distance can be ensured between the water scupper
bore 128 and the opening 158 in the intake duct 15 to prevent
the suction of water through the opening 158. Similarly, the
water scupper bore .129 in the second resonant chamber 18 is
provided in a rear portion of the second resonant chamber 18
and hence, a suffici!ent distance can be ensured between the
water scupper bore 129 and the communication pipe 159 of the
intake duct 15 to p.revent the suction of water through the
communication pipe 159. In a state in which the intake silencer
system has been mounted in a vehicle, the four subsidiary
silencing chambers l9a, l9b, l9c and l9d open laterally
(horizontally) and hence, the single water scupper bore 12~ may
be provided in the first resonant chamber 17.
The operation of the embodiment of the present invention
having the above-described arrangement will be described below.
The open air drawn by a negative intake pressure generated
by the operation of tble engine is supplied to the engine through
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the aircleaner28,theintakesilencersystemRandthethrottle
body (not shown). At this time, the inside of the intake duct
15 of the intake silencer system R communicates with the inside
of the first resonant chamber 17 through the opening 158 and
with the inside of the second resonant chamber 18 through the
communication pipe 159 and hence, noises of two different
frequency bands can be damped by the first and second resonant
chambersl7andl8eachfunctioningasaresonant-typesilencer.
As can be seen from F.Lg.7, the second resonant chamber 18 having
a large volume, dampens the noise of a relatively low frequency
band, and the first resonant chamber 17 having a smaller volume
than that of the second resonant chamber 18, dampens the noise
of a higher frequency band.
At the same time, each of the four subsidiary silencing
chambers l9a, l9b, 19c and l9d separated from one another by
thethreeribsllg,lllOandll1lwithinthefirstresonantchamber
17 functions as a side branch having a resonant effect and is
capable of damping noise of a frequency band depending upon the
size and shape thereof. As can be seen from Fig.2, the case
sidewall 1180f the first case half 11 is formed to extend along
the fender 23 inclined with respect to the center plane P (see
Fig. 2) of the vehic:Le body and hence, if the tip ends of the
three ribs 119, lllO.md 1111 extending from the case sidewall
118 toward the center plane P of the vehicle body are trued up
in a longitudinal direction of the vehicle body, the length of
each of the ribs 119 to 111l is automatically and gradually
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14
decreased. As aresult, the foursubsidiarysilencingchambers
l9a, l9b, 19c and l9d are decreased in volume in the order of
l9a ~ l9b l9c ~ l9d and hence, are capable of damping the
noises of a lower frequency band to a higher frequency band in
the above-described order, respectively, as shown by a solid
line in Fig.7. A dashed line in Fig.7 shows a silencing effect
provided when the first resonant chamber 17 dose not have the
ribs 119, ll1o and 111l (namely, the subsidiary silencing
chambers l9a, 19b, l'~c and l9d). If the silencing effect shown
by the dashedline is comparedwiththatshown bythe solidline,
the noise damping effects (see obliquely lined areas) provided
by the subsidiary si:Lencing chambers l9a, l9b, l9c and l9d can
be confirmed.
In this way, it is possible to effectively dampen the
noiseofafrequencybandwiderthanthatofthepriorartwithout
anincreaseinsizeoftheintakesilencersystemRusingasimple
structure in which the plurality of ribs 119, lllo and 111l are
formed only within the first resonant chamber 17. Moreover,
the ribs 119, lllo and 11ll integrally connect the three wall
surfaces of the first resonant chamber 17, i.e., the case upper
wall 112, the recess upper wall 16l and the case sidewall 118,
and hence, it is possible to remarkably enhance the rigidity
of the first case half 11, and prevent the generation of a
radiated sound due to the vibration of the wall surfaces 11l,
118 and 161.
CA 022449~l l998-08-l2
Particularly, the ribs llgto ll11integrally connect the
two largest opposed wall surfaces of the first resonant chamber
17(namely,theupper-sidecaseupperwallll2andthelower-side
recess upper wall 16l) and hence, it is possible to effectively
inhibit the radiated sound from the case upper wall 112 which
is liable to be vibrated because of its large area, and the
radiatedsoundfromtherecessupperwalll61. Further,because
the distancebetweenthecaseupper wallll2andthe recessupper
wall 161 is relatively small, the height of the ribs 119 to 11
can be reduced. Thus, the rigidity of the ribs 119 to 11
themselves can be enhanced, and also the thickness of the ribs
119 to 11ll can be reduced to mini mi ze an increase in weight.
Moreover, the ribs :L19 to 11ll are disposed at substantially
equal distances~ which is convenient for enhancement in
rigidity of the first case half 11.
The first case half 11 and the second case half 12 are
made from a synthetic resin by an injection molding, wherein
the ribs 119 to 11ll and 11l2 are formed in a direction
perpendicular to the mating face 13 corresponding to a parting
face of a mold for forming the first case half 11. Therefore,
it is easy to release the formed first case half 11 from the
mold, and the structure of the mold can be simplified. Also
the four subsidiary silencing chambers l9a, l9b, l9c and l9d
can be formed without subjecting the formed first case half 11
to a special treatment.
By the fact that the intake duct 15 is clamped between
CA 022449~l l998-08-l2
16
and fixed to the mating faces 13 of the first case half 11 and
the second case half 12, a special member such as a bolt and
the like is not required for such fixing. Moreover, as can be
seen from Fig.6, the mating faces 13 clamping the intake duct
15 are offset remotely from the ribs 119 to 111l with respect
to the central portion of the intake silencer system R.
Therefore, the subsidiary silencing chambers l9a to l9d having
a sufficient volume,_an be formed without consideration of the
interference of the ribs 119 to 111l with the intake duct 15.
A second embodiment of the present invention will now be
described with reference to Fig.8.
As can be seen from the comparison of Figs.6 and 8 with
each other, the cross'section of the intake duct 15 in the first
embodiment (see Fig.6) is formed into a circular shape at its
upstream portion ancl lnto an elliptic shape having a longer
diameter in a direct:Lon parallel to the ribs 119 to 111l at its
downstreamportion,~hereasthecrosssectionoftheintakeduct
15 in the second embodiment (see Fig. 8) is formed into an
ellipticshapehavingashorterdiameterinadirectionparallel
to the ribs 119 to 1111 at both of its upstream and downstream
portions. As a resu:Lt, the length of the ribs 119 to 111l can
be prolonged without: lnterference with the intake duct 15,
leading to a further increased freedom in determining of the
size and shape of the subsidiary silencing chambers l9a, l9b,
l9c and 19d.
Although the embodiment of the present invention has been
CA 022449~1 1998-08-12
described in detail, it will be understood that the present
invention is not limited to the above-described embodiments,
and various modifications in design may be made without
departing from the spirit and scope of the invention defined
in claims.
For example, the four subsidiary silencing chambers l9a,
l9b, l9c and l9d are defined by the three ribs 119, lllo and 11
in the embodiment, but the number of the ribs may be two ormore.
The inclined wall surface of the vehicle body is not limited
to the fender 23 il.lustrated in the embodiments and may be
another wall surface of the vehicle body such as a bonnet and
the like. The cross sectional shape of the intake duct 15 need
not be a mathematically precise elliptic shape, and may be a
shape having both of a longer diameter and a shorter diameter.
