CA1274191A - Fluid filter with pleated filter medium - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An air filter element consists of an annularly arranged pleated filter medium having a plurality of radially extending pleats. Two sides or legs of each pleat are bonded to each other at the outer peripheral side to form an outer bonded section while one sides or legs of the adjacent pleats are bonded to each other at the inner peripheral side to form an inner bonded section, thereby forming a fluid path extending between the adjacent pleats along the length of each pleat, Additionally, outer and inner resilient seal members are to provided that a part of each outer bonded section is embedded in the outer seal member while a part of each inner bonded section is embedded in the inner sealing member.

Description

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FLUID FI~TER WITEI PI-~5ATE;D FILT$R MEDIUM
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BACKGR~UND OF THE~I~VENTION

The present inven~ion relate~ generally to ~luld fil~ers ~or flltering flu~d~ ~uch a~ air~ fue~, lubricating oil And hydraul~c fluid used in inte~nal çombu~t~on engine~ to remove lmpurltie~ ~u~h ~ d~
and metal powder~ there~rom, and ~oxe particularly ~o 1~ ~n imp~ove~ent in ~n pleated ~llter medlum of ~uch ~luid fil~er~ there~y to attain ~ hlgher fllterin~
ablllty and a longer filt~r life.
~ ~e~cri~tlon of ~he ~rior Art . .... ~
M~t automotive internal combustion en~lne~ ~re equipped ~ith ~lr and lubric~ting oll filter~ whose filter ele~ent u~u~lly con~i~ta o~ ~ plea~ea fil~çr medium formed of a ~h~et-type filter materi~l ~uch as ~ilt~r paper or non~oven f~brlc~ The ple~ted ~llter medium i~ gener~lly annul~r ~nd ha~ ~ plu~llty o~
longitudin~lly ~xtending plea~. A palr of end plate~ ~re ~e~lin~ly ~aohed ~o the Oppo8~ te end~ of the annular filter medium by me~nff o ~dhe~ive, ~ecurely dispo~ing ~n inner per~or~ked çyllnder along the inner perlphery of the annular ~i~ter medlum.
Additlon~lly, a pair o~ fluld ~ealing member~ are ~ecurely attaçhed to the end plate~, re~pe~ively, thu~ constituting the fllter element. With ~uch ~
filte~ ele~ent, fluid ~uch a~ air or lubric~ing oil to ~e filtered ~lows perpend~c~l~rly to the filt~r m~dlum~ i.e., the fluld i~ introd~ced through the outer p~ripheral face of the filter medium and ge~s out through the inner pe~lpher~l f~oe of the fl~ter medium ln which du~t and the like ~re remo~ed ~nd .
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retained on the ~ur~ace of the ~lter medi~m.
However, varlous drawb~ck~ have been encountered in euch conven~onal fllters ~ di~c~ed herein~ter. tl) Since the ~ur~ce ~rea of the lnner periphery of the ~1ter medlum i~ con~ider~bly ~maller than that of the outer perlphery of the ~ame~
flow re~l~tance of the ~luid pas~in~ through the filter medium depend~ on the ~maller ~urfaae area of the ~ilter medi~ inner pe~lphery~ thereby increa~lng ~he flow resistance con~iderably over a level corre~ponding to the largeL surfaoe ~re~ of the fllter medlum outer periphery. (2) Close çontact be~ween t~e adjacent pleats oçcurs with pa~sage of the fluid ~nd with pro~re~ of clogglng of She fllte~
medium. This decrease~ the effective filtering ar~a of the filter medlum, thereby ~hortening the life of the fllter. t3~ In ~ ~tate where the filter element i8 installed in a ca~in~, it i~ usual that the fluid to be filtered fl~w~ perpendlcularly to the outer perlpher~l face of the fllter medlum and p~es through the filter medium, and thereafter the flow direc~ion o~ khe fluid i8 bent approximately ri~ht anyle~ ~o get out through ~n fluid outlet plpe provided at the c~ntral part of the ca~ing~ This incre~e~ the flow re~l~t~nce of the fluid flowing throuqh the filter~ t4) The ~luid intro~uced ln~ide the ca~lng through the fluid inlet pipe cannot be uniformly dl~trl~uted throughou~ whole the oute~
per~pheral face of t}ie filter medium ~o that the ~luid i~ ~uck~d in lar~er ~ount through a part near the ~lr lnlet pipe and in smaller a~ount through a p~rt remote from the air lnlet pipe~ Accordingly, the filtration rate ~t the p~rt ne~r ~he inlet ~7~

becomes higher than an appropriate value while the fluid is difficult to flow at the part remote from the inlet. As a result, it is impossible to obtain a higher filtering accuracy and a longer life of the filter. 5) Since the pitch of the pleats is smaller at the filter medium inner periphery -than at the outer periphery, the flow resistance and the life unavoidably depend on the pleat pitch of the filter medium inner periphery. Accordingly, if the number of the pleats is increased and the width of each pleat is enlarged for the purpose oE lowering the flow resistance and prolong the life, effects thereon are hardly expected.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a fluid filter for an automotive engine, comprising a filter element including a pleated filter medium having a plurality of pleats, the plurality of pleats defining adjacent pairs of first and second pleats, each pleat having first and second sides which are integrally connected through a first score line with each other to form an upwardly-pointing pleat portion, the second side of the first pleat and the first side of -the second pleat being integrally connected through a second score line with each other to form a downwardly pointing pleat portion, each pleat side having oppositely located first and second end sections which have Eirst and second edges, respectively, which extend substantially perpendicular to each score line, the first end sections of the first and second sides of each pleat being approached and bonded to each other to form a plurality of first bonded sections, the second end section of the first pleat second side and the second end section of the second pleat first side, of the adjacent pairs of first and second pleats, being approached and bonded to each other to form a plurality of second bonded sections; and at least ~7~
- 3a one of first and second inclined walls, the first and second inclined walls being inclined to the second score line and the first score line, respectively, -the first inclined wall being formed between the first pleat second side and the second pleat first side, the first inclined wall having an edge contiguous to the first edges of the first and second pleats, the first inclined wall being integrally connected through a third score line with the first pleat second side and through a fourth score line with the second pleat first side, the third score line connecting an end point of the second score line and a first point lying at border between the first edge of the first pleat second side and the edge of the first inclined wall, the fourth score line connecting the second score line end point and a second point lying at border between the first edge of the second pleat first side and the edge of the first inclined wal.l, the second inclined wall being formed between the first and second sides of each pleat, the second inclined wall having an edge contiguous to the second edges of the first and second sides of each pleat, the second inclined wall being integrally connected through a fifth score line with the first side and through a sixth score line with the second side, the fifth score line connecting an end point of the first score line and a third point lying at border between the second edge of the first side and the edge of the second inclined wall, the sixth score line connecting the first score line end point and a fourth point lying at border between the second edge of the second side and the edge of the second inclined wall -1~

By vlrtue of the filter ~edium confl~ur~ted ~uch that the ~p~ardly-polntln~ ple~t and ~he downw~rdly-pointin~ ple~t are alternately clo6ed and opened at their oppo~ite end~, the flow pa~h o~ a S fluld ~o be filtered is formed nearly alon~ the length of e~ch pleat in which flltr~tion i~
ac~omplished in a proce~ of the fluLd flowing alonq the pleat length so that i~purities are uniormly ret~ined throughout ~hole the ~ilter medium.
~ccordlngly, the fluid to ~e flltered i~ unifoLmly di~tributed throughc~ut whole the sur~ce of th~
ilter medium, thereby unlfor~alizing flo~ of the fluid flowin~ through the filter ~edium and fitrAtion rate. Addit~onally, A ufflc1ent cle~r~nce ~
~e~urely for~ed between adj~cent pleat~ eYen ~t inner periphery of th~ filter ~edium and therefore the adjacent plea~s are preven~ed from c~lose contact to each other even if cloyging of the fil~er medlum progre~e~r thereby increasing effective fllt~at.~on area~ lrhu~ ~he Eilter m~dium ~f the pre~ent in~ention effectively impro~e~ filtr~tion accuracy and prolongs the lLEe oE the filter elemen~.
E~ E ~ ~ CRIPTIOM ~ T71E ~RAWlNGS
Th~ featuref~ and advan es of the fl.uid ~ilter ~ccorclinc3 'co the pre~ent 1nvqn'cion wi11 ~e more c~eArly appreci~ ea ~rorn ~h~ ~ollowing descriptiot-taken ln conjunction with the accompar~y1ng draw1ng~
in ~hiah like ref~r~nc e numeralg de~lgnate corre~pon~ing elenlen~s and y~ts, in wh1cht Fig. 1 is a vertical ~eoti~nal vlew of ~ flrst embocgiment o~ ~he ~luid f ilte~ in accordance with the r,~

pre~ent lnvention) Fig. ~ plan view of a $~1ter ~lement of the fluld filter of Fi~. lJ
Fig. 3 i~ a front elevation of ~he ~ er element of Fig. ~;
Fig. 4 i~ a fragmentary perspec~lv~ view of a ~ilter mediu~ u~ed in the filter element o~ ~19. 2;
Figs. 5A to 5C are illu~ration~ fihowing a method of fo~min~ the filte~ medium by pleating a flat fllter ~aterial, in which Fl~. SB i~ ~ plan view of the flat filter material with ~core~ and ~dhesive applied thereon, and Figs. 5A ~nd 5B are side view~
of the ~ilter m~terlal after ~eing ple~ted, respe~tively;
Fig. 6 i~ a plan view o~ a ilt~r element of a ~econd embodiment o~ the fluid filter in accord~nce with the pre~ent invention;
Fig~ 7 is a ~ront elevatlon of the fllter element of Flg. ~;
~i~ . 8 iR a ~ide view of the filter elemen~ of E'ig. 7i Flg. 9 i~ a fragment~ry per~pective view of a ~ilter medium o~ the fllter element of Fig. 6;
Fiy. 10 i~ ~ vertical ~ectlonal view of ~he second embodiment fluld filter;
Fig. 11 i~ a plan vie~ of ~ filter element of a third ~mbodiment o~ the fl~ld filter according to the p~e~ent lnventiont Fiy. 12 1~ a front elevation of the ~ilter 3o element of Fig . 117 Fig. 13 i~ a fragment~ry per~pective view of a filter mediu~ of th~ ~ilter ele~ent of Pig. 11;
Flg. 14 i~ a vertical ee~tlonal view of the -1~7~

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third embod$ment fl~id filter:
Fi~. 15 iB ~ verti~ c~onal view o~ a ~ er element of a fourth embodiment of the fluid filter according to the pre~ent inven~ion;
Flg. 16 is a front ele~ation of ~ flltex elemen~
provided wi~h a ~ilter ~edium ~uppor~ ~truc~ure~ of a fith e~bodiment of the fluld filter according to the present inve~tlon 7 Fig. 17 i~ a fr~gment~ry per~pective view of a filter medium of the f ilter element of Flg. 16~
Fig. ~8 1~ ~ plan vlew of the filter element of Fig~ 16 showing the ~t~ture of the filter medium and the ~upport structure;
~ig. 1~ i6 a front elevation of the ~upport ~truçture of Fig. 16 Fig. 20 is a pl~n view of the fi~th embodiment fluid filter ~ccordlng ~o the present lnvention;
Flg. 21 a vertical nectional view of the $1uid fl~ter of ~ 07 Fig. 22 i~ a vertical ~ectional view of a ~ixth embodiment of the fluid fllter ~ccording to the peesent inventlonJ
Fig. 23 is a vertical ~ectional view oE a ~eventh ~mbodiment o~ the ~luid fil~er in accordance with the pre~ent lnvention;
Fig. 24 ia a vertlc~l se~tion~l ~iew o~ an ei~hth ~mbodiment o the fluid Eilte~ in acco~dance with the pre~ent invention7 Fig. ~S 1~ a per~pective view o~ A Eilter ~edlu~
o~ a filter element of the ~luid filter of Fig. 24J
Fig~ 26 i~ an illu~tratlon ~howing a pleating pattern of A fl~t filter material to form the Pllter medium of ~ 5;

- - -Flg. 27 1~ a f rag~entary per~pec~ive view of the filter medium a~ter plea~ed according to the pleating pattern of Fig. 26;
Figs. 2a to ~o ~re illu~trations simi~ar to F1~ but -~howing ~u~ther pleating p~tterns of a flat filter material to form filter medium~ simll~r to tha~ of Fig. 25;
Fig. 31 is a vertic~l ~e~tionAl vlew of a nlnth embodiment of the fluld filter in accordance with the 10 pre~en~ inven~ion; and Fig. 32 1~ a ver~ical sectional view of a ten~h embodiment of the fluld fil~er in accordance wi~h ~he present lnvention.
DETA LED DESCRIPTION OF Ttl~; INVENTION
Referring now to Fig~. 1, 2, 3 and 4, there 1 ~hown a ~ir~t embodiment of a fluid filter in accordance with the present in~ention. This ern~o~lment i~ directed to ~n air filter 10 ~or an automotive lnternal aom~u~tion engine. The air

2~ filter 10 comprise~ a ca~lng 12 w1thin whlch a filter element 1~ ec~rely di~po~ed to remove dust contalned ln alr to be ~uppli~d to the en~ine. A~
shown in ~ig~. 2 and 3, the ~llter elemen~ 14 con~i~t~ of a plea~ed filter medium 1~ formed of a ~heet-~ype f1lte~ m~terlal ~uch a~ a fllter paper or a nonwoven ~abric. The ~llter medlum 16 1~ formed annulAr in ~hi8 embodiment. A~ clearly shown in Flg. 4, ~he filter medium 16 ln~lude~ r~llty of plea~ 18 which extend ~dlally bet~een the inner and outer perlpherle8 oE the filter medium 16.
The ~tructure o~ the filter medium 1~ will be di~cus~ed herein~ter p~rticularly with re$erence ~o Figs. ~ in whlch ad~acent two tfir~ ~nd ~econd) pleat~ ~A~ ~B al~e sho~n forminr~ part o~ the plurAlity of pleats ~ ch pleat 18A, l~EI lnclude~ fir~ and ~econd ~ides 20a, ~Ob which flre lnteyfally connect~d or contl~uou~ thro~h a upp. r or f lr3t main ~core 7 lin~ 22 thereby to form an upsJardly-poini:ing pl~
correspon~lng to that ~A~ ~dditionallys ~he second slde ~Oa of ~he first pl~at l~A i~ int~gr~
connected or ~ontiguous through a lower or s~cond main score line ?4 with the ~lr~t slde 20~ o~ the second pleat 18B ~hereby to form a downwardly-pointing pleat (not identif ied) ~ ~ch ple~t ~ide Ob has outer and inner ~first ~nd se~orld~ end ~ectlons 2~a~ 2~b which contain outer ~nd inner flrst.
and ~econd edges ~6~ b, rq~p~;:tively, edye 26b is best seen 1~ f rom F ig ~ ~ . It wlll b~ under3tood that e~h e~e 26a, 26b is perpendicular to the upper main score 1 in~ 2~ .
~ e outer end sectlon~ 2~a, 24a of the ou~er an~
inner slde~ of e~ch ~leat 18 ~l~A, 18~) are ~pproached and bonded with each other by means of an adhesive, thus forming ~n outer or fir~t bPnded section ~1~ The inner end Bection 24b of the second slde 20b of the ~ir~t ple~ A 1~ appLo~hed an~
bonded to the inn~r end ~ectl~n 24b oE the fi~t ~ide 20a of the second ~le~t 18B by mean~ of ~n adhe~ive, thu~ ~ormlng ~n lnne~ or ~econd bonded ~ec~ion s2.
I~ will be under~tood that the outer end ~ect~on ~4 ~ont~ining the oute~ edge 26a) of the pleA~ side 20~, 20~ extend~ ~ro~ the upper main sco~e llne 2~
~o and h~ a length ~lighkly ~m411~r ~h~n th~ ~idth w ~f the pl~t ~ide~ ~imilarly, the lnner end ~ection 24b contalnlny ~he lnner edge 26b of the ~lea~ slde 20~, 20h ex~ends from the lower m~in score llne ~4 ~nd h~

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a len~th ~ htly ~mallel th~n th~ width W of the ple~t slde~
As clearly shown ln Flg~ 4, an out~r or fl~t inclin~d ~all ~8 of the ~hape of ~n is~sceles trian~le is ~ormed ~etween ~he firs~ ~nd second pleats 18A, l~B on the outer peripheral ~ide. ~he outer lncllend wall 28 ha~ an ed~e ~0 contiguous to the outer ed~es 26a of the plea~ f ir~t and ~econd eide~ 20a, 20b. The ou~er inclined wall 28 ls integrally connected or contiguo~s ~hrough a fir~t obli~ue score line 32a with the second side of ~he fic~t pleat l~A and throu~h ~ ~econd ohllqu~ s~ore line 32b wlth the first ~ide ~Oa of the 6eGond pleat ~, The fir~t obll~ue ~core llne 3~a conn~cts an end point 34 (on the ou~er peripheral side) of the lower mAln ~core line ~4 and a point 36 lying at the border of the outer edg~ 26~ of the ~econd side ~Ob o~ the flr~t pleat lgA and the edge 30 of the outer inclined w~ 8, ~he second ~blique score line 32 connects the end point 34 o t.he lower main ~ore llne 24 and ~ p~int 38 lyiny at the border of the outer edge 26a of the fir~t side 20a of ~he ~econd pleat l~B and the edge 30 o~ the first inclined wall 2~. .
In addition~ an inner oe ~econd inclined wall 40 o~ the shape o~ an iso~c~les tri~n~le i~ focmed conti~uoUB to the upper main score line Z2 and ~o~ed hetween the f irs~ and second sides 20a, 20b o~ each plea~ A, 1~) on the inn~r peripheral ~ide.
30 Th~ inner irlolln~d wall ~0 ha~ ~n ed~e 42 c~o~ltlguou~
to ~he outer inner edge~ 26b of the fir~t And ~:econd slde~ 20a, ~Ob o~ ea~h pleat 18 ~lBA, l~B). ~he inner inclined wall 4~ i~ inteyrally ~onnected or '~

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contlguou~ through a third oblique ~c~re lln~ 44a wlth ~he fir~t ~lde ~O~ of the pleat and through a four~h obllque ~core line 44b with the second ~ide ~Ob of the pleat. The thlrd o~llqu~ ~core llne 44a conne~t8 ~n end poln~ 46 ~on ~he inner peripheral side) o~ the upper maln ~co~e line ~2 and a point 0,8 lying at the bo~der between the inner ed~e ~6b of the f ir~t ~ide 20a of th~ pleat and ~be edge 42 o~ the inner inclined ~all 40. The four~h obllque ~core 10 llne 44b connects the end point 4~ of the upper maln score llne 22 and a polnt S0 lying at the bo~der between the edge 42 of the flecond inclined w~ll 40 And the edge ~b o~ the second ~ide 20~ o~ the pleat.
To facllltate unde~tanding the ~ruc'cure o~ ~he 15 f ilter medium 16 ~ a me~hod of m~king the ~llter nedium will l;e dlacu~sed with re~rence to Fig~0 5A, 5~ and 5c. A f il~er material F such ~ ~ f llter paper of the b~nd type i8 ~c~red l~y suit~ble me~n~
~h ae roll~ ~not ~hown~, aacording to a pattern of 20 Flg. 5B in ~hich solid llne6 indlcate ~cores formed on the front ~lde Sl tcorre~pondlng to the ~ho~n side of the filter medium in Flg~ 4 o~ the filter medium 1~) while ~roken line~ indicate ~core~ formed on the ~ever~e ~lde s2. Each Y-;h~ped ~core~ on the front 25 side S~ include a long atr~lght score a, ~nd ~wo oblique ~hcrt scoreB a' ~ a~ haviny the ~ame l~nyth.
The ~core a corre~pon~s to the lower maln ~core line ~4 in the f llter medium 16 8hown ln Fig . 4, whi le the scores a I, a" corre~pond to th~ f irst and ~econd 30 obllque ~core lin~ 32a, 32b, respectively. Each Y-shaped ~aores on ~he reverse side S2 lnclude a long 8traight ~core b, ~nd ~wo o~lique short ~ores b ', bn having the ~ame length. The ~core ~
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corresponds to the upper m~ln score line 22 of ~he filter medi~ hown in Fig~ 4, while the score~
b', b" co~re~pond to the third and fourth oblique score lines 44a, 44b, re~pectlvely.
An adhesive S~ is applied in the ~orm of ~ band h~vin~ a predetermined width onto the front side s~
at a continuous end sectivn 54a extendlng alon~ an ed~e 56a~ The ~dhesive is also applied in the ~ame mann~r onto the rever~e side S2 at ~he other continuo~ end section 54b extending along the other contin~ous edge 56~ Th~ ~ajor part of the contlnuous end ~ection $4~ forms the inner end se~tlon~ 24b of the fir~t and secon~ si~e~ 20a, 20b o~ the pleats 18~ Simil~rlyt the major p~rt o~ the other contin~ous end ~ec~ion 54b ~orms the outet end sectlon~ 24~ of the fir~t ~nd second sides 20a, 20b of the pleat~ ~8, Thereaft~rt the bAnd type fil~er m~teri~l F is pleated by sui~able means such as a pleating machine ~no~ shown), ~here~y ~eing hent along the ~cores into a zig-zag shape as seen ln Fi~ SA and SB in which the ~core a form~ thQ top of th~ upwardl~pointing pl~at while the s~ore b form~ the bottom o~ the downwardly-polntirlg pleat. Th~n, the ~ection~ c', c"
f l.h~ ~rJ~ s~ctl~n 54~ with th~ adh~sive ar~
approache~ and bonded to e~ch uther except for the section between the score~ a' ~ ~" in ~uch a manneL a~
~hown ln F1y~ sc ln which a part oE the i809celes trian~le sh~pe ~ormed by the ~core~ ~ ', a~
3o corre~pond~ to ~he outer lnclined w~ll 28 of the filter medlum 1~ ln Fi~. 4. It will be under~tood that th~ ~e~tions c ', cl~ cor~e~pond to t~)e outer end ~ection~ 24a, 24a of the ple~t fir~t and ~econd ~ides ~' ~7~Lg.~
~12-202, 20b illustrated ln Fig. 1~ Slmilarly, the ~ectlon~ d', d~ of the end ~e~ions S4a wlth the adhesive are appro~hed and bonded to each other except fo~ the æection between ~he sc~res b', b" in ~u~h a manner a~ ~hown in Fi~. SA in whi~h a p~r~ of the iso~cele6 trl~n~le shape formed by the s~oe~ b~o b" corre~pondq to the inner inclined wall 40 sho~n in ~ig. 4. It will he under~tood th~t the sectivns c~;
c" corre~pond to the lnner end ~ections 24b, 24~ of 1O the pleat fir~t and ~econd slde~ 20~, 20b illus~rated in Fig. 1. ~he thus formed fllter medlurn 16 wlll ~ake a Rhape having ~ longer outer periphery and a ~horter lnner periphery. This i~ becua6e ~he len~th of the edge 30 of the outer inclined wall 28 i~
larger than ~hat of ~he ed~e 42 of the inner inclined ~all 40. Sub~equently, the inltlal end 60 and the ~erminal end 62 ~shown in Flg. 2) of the fll~er mediu~ 16 are bonded to each other, thereby forming the annular filter mediu~ 16 ~ ~hown in Fig. 2.
Accordinyly, ~he length o~ the outer periphery of the annula~ fllter m~dium 16 corre~ponds to the total of the length of all the ou~er lnclined wall edges 30 ~nd ~he th.ickne~ ~f ~11 the outer bonded ~ectlon~ Bl, while the length o~ the inner periphery f the same filter medium 16 ~o~e~pond~ to the ~ot~l o~ the length of ~11 the inner inclined wall edges ~2 and th~ thickne~6 of ~11 the inner bonded ~ec~lons B~ will be under~tood that the length of the edge 30, and of ~he first and ~econd obllque ~core 3o lines 32a, 32b ~efining each inner inclined wall 28, and the length of the ~dge 42 and of the third and fourth oblique ~core llnes 44a, 44b defining the inner inclined w~ll 4D are suitably 6electable f or ~L2 the purpo~e of altering lenyth o~ ~he inner and ou~er peripherle~ of the annula~ filter medium and/or ~he width ~nd length of the 8pace formed between the ad~ace~t pleat~.
A~ seen from ~lg q 1 to 3, an outer annular resilient ~ealing ~ember 64 is ~o provided th~t the radlally outward ~ection or outer peripheral section of the outer lnclined w~ 28 and the lower part~ of the outer bonded ~ection~ Bl ls embedded thereln.
The outer ~eallng member ~4 extends radi~lly and ou~wardly in the ~hape of a flar~ge. Add~tlonally~ an inner annular re~ilient ~ealing mem~er 6~ i~ 80 provlded that ~he radi~lly out~rd ~ection or the outer perlpheral ~ection of the inner inclined walls 4~ mbedded theeein. $he inner ~ealing member extend~ r~dially ~nd inwardly in ~h~ shApe of a flang~. ~he inner ~ealing member is ln parallel relatlonship with the outer ~ealing me~ber ~4. The inner and outer ~eali~g members 64, 6~ are formed of a relat~vely ~oft plastic ~uch a~ foamed polyurethane or polyvinyl chloride. It i~ prefer~ble to form the ~ealing me~be~ ~4, 66 of soft ~oamed polyureth~ne thereby improving i~ sealing ability. ~hç inner And outer ~ealing members 66 ar~ molded lnto the above-mentioned shape ~o that part~ of th~ annular fllter medium 16 are em~edded therein, th~ forming the fll~er el~ment 1~.
The filter element 14 ~ shown in Figs. 2 ~nd 3 are dispo~ed withln the ca~ing ~2 in a fashlon ~hown in Fig. 1. The ca~lng 12 includes a bowl--like body 6~ which 1~ formed ~t it~ central ~ection with an a$r outlet pipe 7~ through which alr i8 sucked into the en~ine. ~he alr outlet pipe 70 i8 loc~ted coax~l ~'7~

with the bo~y ~8. The body ~ further ~ormed at it~ outer periphery wlth an annular ~lange 72 extending radially and outwa~dly. Additionally, the body 6B 1~ provided with a b~idge member 74 extend~
ln the oppo~ite direction ~o the pipe 70. An annular flan~e member 7~ is secured onto ~he top ~ection of the bridge member 74. A cover 78 is det~chably conn~cted to the body 58 and ~ormed with an air inlet pipe 80 through which ~lr is supplie~ in~ide the c~lng 68. The cover 78 is Eormed at the lowe~
perlphery with a radlally inwardly extending annular flange B2 facing the body annular flange 7 Additior~ , the cover 78 i~ depre~ed at it~
central ~ection to form ~ fl~t portion 78a facin~ the Annul~r ~l~nge m~mber 76l Ag illustrated in Fig. 1, the outer je~llng mem~er 64 of the filter e}ement 14 i~ disposed between the body annular fl~nge 72 And the cover annular fl~nge R~ while the inner ~ealing member ~6 iæ di~po6ed ~etween the body ~ide annular 2~ flang~ momber 76 and the cove~ flat portion 78a~ The outer and ~nner sealing members 64, 66 are ~ecured ln position by tightening ~ bolt 84 pas~lng through the cover aentral ~lat port.ion 78~ and the body ~lde brldge ~embex 74 ~o ~e engaged with ~ nut ~6 located 25 beneath the bridge ~ember 74. A~ ~een from Fi~. 1, the air inlet pipe 80 And the ilter element 14 i9 in such a relatlon~hip that the ~xis of the ~lr lnlet pipe 80 i8 in an im~gin~r~ horizontal plan~ parallel with an lmaglnary plane contalnlng the upper main score line~ 22. Additi~nally, the alr lnlet pipe 80 i8 loc~ted in such a level that a maior part o~ the outer bonded section Bl of the pleat 18 i~ within the exten~ion of t~ in~ide openin~ of the air inlet. plpe 80.

~ ~7;~

Wlth the thu~ arran~e~ air ~ilter 10, d~lrlng engine operatlon, a~r containing du~t and the like is ~ucked through ~he air inlet pipe ~0 into the insi~e of the ca~in~ 12 and guided along the outer pe~iphery 5 of the annular filter medium 1~ thro~gh an annular ~çe ~ormed between the inner peripher~l ~urf~ce of the cover 78 and the outer perlphe~y of the annular filter medlum 1~. The thus guided air flowY n~rly along the length o each pleat 18, accomplishing filtering o~ dust and the like. Addltionally, ~he guided air ~low~ throu~h the upper face tcontaining the upper main score lines 22) of the filter ~edium 15 and directed nesrly along the length of each pleat 18, accompli~hing ~ er of dust. In other words~ -air to be fil~ered by the filter medium 16 i9 intro~uce~ ~rom the vlcinlty o~ the outer bonded ~ect~on~ Bl o ~he pleats 18 then to flow through an ~longate space ~ormed between the ad~ac~nt pleats 1~, lB, and pa~se~ khrough the filter medium 16 in ~he 2~ vlclnlty of the inner bonded ~ection~ B~ to be supplied to khe englne. Acco~dingly, the air in~.roduced into the ~ilter ca~iny 12 flowa ne~rly alony a gentle parabola connecting the air inlet pipe 80 and the air outlet pipe 70.
Therefore, according to the fir~t embodiment fluid ~ er, the ~ollowing ~lgnlfl~ant ~dvsntAges } ~re obtained by ~irtue o~ the filter medium con~igurated ~uch th~t the upwardly-polnting pleat and ~he downwardly-pointing ple~t are alternately alose~ and opened ~t thelr oppo~ite endE~. ~1) The ~d~ent pl~ats ~re ~epAr~te fcom e~ah other to form a clearanae therebetwe~n even at the inn~ periphery o~ the annul~r fll~er medium, Accordingly~ although ~~

the pitch of the pleat~ ~t ~he filter medl~m inner periphery i~ oon~lderably ~maller a~ compar~d wlth at the filter medium outer periphery, a ~u$ficient ~urface area can be obtained ev~n at th~ fil~er medium inner periphery~ 80 that ~he flo~ ~esi~tance : o~ fluid to be ~iltered and the li~e o~ ~he ftl~er do not depend on ~he pleat pitch at the inne~ periphery o~ the filter m~dium. T~is m~ke~ effect$ve lowering fluid flow re~istance a~d prolong filter ll~e by 1 o ~ea~ure~ of lncreabin~ the width o~ each ple~t ~nd o~
increa~ing the number of th~ pleats~ (~) since the fluid pa6sing th~ugh the ~ilter medium flow~ nearly ~long the ~entle p~r~bola, the dire~ion of flow of the ~luid doe~ not a~Fuptly change in the ~ er, ~hereby lowering fluld flow re~istan~e. ~3) Even in c~se wher~ the fluid pa~e~ through the ~ er medlu~
a~ a high ~peed or cl~gglng of the Ellter medlum progre~se~, the adj~aen~ ple~t~ ~re prevented from clo~e contact wl~h each other, there~y maintaining a highe~ ef~ectlve ~llt~rlng area. t4) Sln~e the fluld ~low~ ne~rly along the length of ea~h pleat, the fluld i~ unl~ormly di~tributed throughout whole the sur~ace of the ~llter medl~, 80 that filtratlon ~ate i8 uniEormalized throughout whole the filter media. Thi~ ~mproveU the filtering accuracy and prolong~ the li~e o the Eilter. ~5) In a state wh~re the fil~er ele~ent i~ in~t~lled ln the ca~ing, l~ge ~olume spac~s are formed on the re~p¢ctlve up~ream And downstream slde~ of the filter element, 33 and therefore pr~s~u~e di~trib~tlon i~ ~nlfor~llæed on the upstr~a~ ~nd down~tre~m ~ldes.
Flg~. ~ to 10 illufitrat~ ~ ~econd embodiment o~
the flu~d ~ilter ~air ~ilter) ~ccordlng to the presen~ inventlon, which i~ ~lmilar to the flr embodiment of Fl~. 1 to 5C with the exception tha~

t~ ~llter medium 16 i8 arr~nged ~tralght and ~lat ~o thAt th~ ~pper ~nd low~r ma~n ~core line~ ~2, 24 are par~llel with e~ch other~ In thl~ e~bodimen~, ~he fir~t ~nd ~econd bonded section~ B1, B~ ~re ~ubstantially the ~ame in length. Addltlonally, the edge 30 and the edge 42 o~ the flr~t and ~e~ond inclined wall~ 28~ 40 ~re ~early the ~me in length wlth each other. ~he fir~t an~ second oblique score line~ 32a~ 32b of the flr~ incllned wall ~ e ne~rly the ~me ln length a~ t~e thlrd and fourth oblique ~core lines 44a, 44b of the second inclined wall~ 40, re~p~ctlvely. As best seen from Flg. 9, the initial end 60 and the t~rm~nal end 62 of the filter medl~ 16 iB ~0 bent ~long a line conne~iny ~he point 36 and the po$nt 50 to be l~ter~lly extend~
A rectan~ular frame-like resilient sealing member S0 1~ provlded to ~e incorporated with the filter medium 16 thereby to f orm a rectangular ~nd ! 1~t filt~r element 16. The resillent ~e~ling member 1~ fo~med of a rel~tlvely ~oft pla~tic ~u~h a~ ~o~med polyurethane re~in or polyvlnyl ~hloride, and ln~lude~ flr~t ~nd ~econd parallel elon~ate ~ections 90~, 90b, and thlrd and ~ourth par~llel elongate section~ 90c, 90d. A~ 6hown in Fiy~. 6 and 7, the outwar~ ~ection of each fi~ inclined wall 28 ~nd the lower-mosk po~tion of each first bonded ~e~tlon Bl are embedded in the fir~t elongate ~ection 90a.
Simil~rly, the out~ard s~c~ion of each eecond inclined wall 40 and the lower-most portlon of each ~econd bonded ~ectlon B~ are em~ed~ed in the second elongate ~ection 90b. Additionally, the ini~i~l and

3.~7'~

terminal ~nd~ of the fllter medlum 1~ ~re embedd~d in the third and fourth ~lnng~te sec~lons ~Oc, 30d~
re~pectively, The fr~m~-like se~lin~ mem~er ~0 i~
lo~ated incl~ne~ relative to a pl~ne containing the upper or lower m~ln scor~ 1 ine~ ~2, 2~ as be~ ~een from Fig. 8~ I~ will be under~tood that the ilter m~dium 1~ of thi~ embodl~en~ is forme~ ~nd in~orpo~ted with the sealin~ member 90 in ~ slmil~
m~nner ~o o~ the first e~odiment, thu~ producln~ ~he filter elemen~ ~4~ The thus produced filter element 14 is ~ecurely and ~e~lingly in~t~lled in the c~ing 12'. The ca~ins 1~' aon~i~t~ of a bo~y 6~' provided wlth an air outlet pipe 70' and formed at its upper p~riphery with a rectangular fram~-like flange 72lo A ~over 7~ provided with ~he air inlet plpe eo ~
and formed ~t i~s lowee periphery with a rectanqul~r frame~like fl~nge ~2' facing ~he flanye 7~' o~ the body 68 ' . The rectangul~r ~r~me-like ~eallng mem~er g~ ls interposed between the 1~nge~ 72 ', ~2 ' and 2~ ~ecured in po~ltion by u~in~ connecting mean~ ~u~h ~8 : wlre-cllps 92 Fig6. 11 to 14 lll~l~trate ~ third embodimen~ o~
the fluid filter ~alr filter) simllar to the ~r~
em~odi~ent o~ Fi~s. 1 to 5C mainl~ with the exceptlo~
: 25 that the filter medium lfi 1~ generally of the fr~to-conic~1 ~hApe. In or~er ~o form the filter medlum 1~ ~ru~o-~onic~l, the l~ng~h ~f the outer bonded ~ec~ion B~ m~lle~ ~h~n that o~ ~he inner bonded section B~ h~ the len~th of the edge 30 3o o~ the ollt~r in¢llne~ wall 2~ rger thnn that of the edge 4~ o the lnn~r ln~lined wall 40 a~ ~een ~Lom Fige. 13 ~nd 14. Additionally, in thi~
embodiln~nt~ ~he length o~ the EirYt and 3econd ~.
',,~

:
~7~

obllque score lin~ 32a, 32b defining the outer in~lined wall 2~ i~ lar~e~ th~n tho~e in the flrs~
embodiment. Such ~ filte~ ~edlum 16 iB incorpo~te~
with the ou~er ~nd inner re~ilient ~eal mem~ers 64 6~ ~o produ~e the f ilter element 14 a~ shown ln Flg~. 11, 12 and 14, ln which the outer peripheral ~ectlon of each outer inclined w~ll 2~ and ~he lower-most portlon of the outer ~onded ~e~tion Bl ~re embedded ~n the outer ~eallng mem~er 64 while the iO inner perlpheral aectlon of eaçh inner in~line~ w211 40 and the lower-most ~ection of the inner bonded 6ectlon B~ are em~edded in the inner ~eallng member 66. The filter element 14 i~ ~ecurely and sealingly ln~talled in the caslng 10 in such a manner that the outer ~e~llng member 64 i~ 6e~u~ely put be~ween the annul~r flanges 72, 82 o~ ~he body 6~ ~nd the cov~r 78 while the inner ~eal~ng member 6~ ecurely put between the body ~lde annular flAnge 76 and the ~epres~ed flat portion 7Ba of the cover 7~ as shown in Flg. 14. ln thi~ embodiment, the c~ln~ 12 lg formed deeper to hou~e the fru~o-conical filter element 14, thu~ obtaining dirty and ~lean ~ide ~pace~ o~ l~rger volum~, formed upstre~m and d~wnstrea~ o the ilter element 14, respectively, wlthln the aasing 12.
Fig. 15 ill~trate~ an e~ential part of a four~h em~odiment o~ the ~luid ~llter ~ir fllter~
~aco~ding to the pre~ent lnv~ntion, whlch 18 ~lmllar to the third embo~lment with ~he exception that a rigid annular plste 100 i~ embedded i~ the lnner annula~ re6111en~ ~enling memb~r 6~. ~his ~ealing m~mber 66 lc lnserted together with a part of the filter medl~m 10 durin~ moldlng of the lnner ~e~ling ~z~

member 66. Accordlng to this embodlmen~ the inner ~ealing member ~ ~ay be directly atta~hed to the ~idge member 74 or directly put between the b~ld~e ~ember 74 and the inner ~r~a~ of the ~o~er 7~ ~o be ~ecured ln position, for ex~mple, by ~ean~ of bolt-and-nut connsction, Fig~ to 21 illu~rate ~ f if th e~bo~lment o~
~he fluld fllter ~ir fil~e~) aocording to the pre~en~ lnvention, which is simila~ ~o ~he ~hird e~odlment of FigB~ 11 to 14 ~lnly except for provislon of a generally frus~o-~onical ~eletal ~upport structure 110 on which the ~ener~lly ~ru~to-conlc~l filter medlum 16 i8 8ecurely dlBpO~ed to for~ the filter ele~nt 14. The ~uppo~t ~tructure 110 of thl~ embodiment i9 in one-piece con~truction.
As shown in Figl 17, each inner inclined wall 40 oon8i8t8 0~ a trlangul~r ectlon 40a and a rectangulat ~ection 40b~ The ~ectangul~r ~ection 40b 1~ de~ined by two nearly parallel score llnes ~1~ L~
~hich form part of ~h~rd and ~ourth obllque ~core line~ ~4a, 44~, resp~ctively~ ~he score line~ Ll, L2 may be not p~r~llel. The parallel ~core 11ne~ L~
have ~he same length ~nd exten~ nearly parallel (or wi~h a ~ligh~ inclination) with the upper main sc~re ~2 of the ple~t lB ormed ~ith the rectan~ulDr ~ect1on 40~, ~hereby making the r~ctangular ~ec~ion gene~ally ~lat or generally par~llel wl~h ~he upper maln ~core lin~ 22.
As be~t ahown ln Fig~. 18 ~nd 19, the ~upport ~trua~ure 110 iB gene~ally ln the fru~to-conical ~hape and includes an ~nnular beam ~e~tion 112, A
plurallty of ~r~ight b~am ~ections 114 are int~g~ally connected wl~h ~he annular beam ~ec~lon ~2 11~ . The f il er medium 16 iB mounted on the beam ~ctions 11~, 114. In thi~ regard, each ~traigh~
beam ~ection 114 i~ formed incllned relative to an lmayinary radial vertloal plane tnot identif ied) in or~er th~t the downw~rdly-pointlng pleat ~ B preven~ced from coverlng wi~h the straight beam eectlon 114 an~
that m~ny downwardly pointlng pleat~ can be supporte~
by each str~ight beam #ection 114. Ea~h straight ! beam ~ect~on 114 h~ a rec~angular cros~-section or may ha~ a ci~cul~r ~ro~ ection ln order to reduce flow re~lstance of the fluid p~ing ~hrough the fllter element 14.
~ lower ~upport ring 116 ~ ~o provided to be ln~egrally connected with the lower ends of the respecti~e ~tralght beam ~eotlon~ 114. The lowe~
~upport ring 116 ic formed with a plurality o~ long PrOieCtiOn5 11~Q And ~ plurali~y of short projec~ions 118b. Bach long p~oje~tion 11~ extends along the lower ~upport rin~ 116 and located midway between two 20 portion~ to ~h~ch ~he low~r end~ of the ~Jacen~ two ~traight beam ~ection~ re inteyr~lly connected.
E~ch ~hort proJec~lon ll~b is located at a portion to whlch the lower end o~ each ~traight be~m ~e~tlon 114. Addi~ionall~, the lower support ring 116 i~
formed with a plur~lity of long through-hole~ 120~
and a plurality oP ~ho~t ~hrough-h~les 120b. Each long through-hole 120a i~ positioned near the long projectivn 118~ and on the ~l~e of the outer periphery of the lo~er ~upport rlng 116. Eaeh short 3o through-hole 120b i~ po~itioned ne~r the ~3hor~
projection llab and on the ~lde of the outer periphery of the lower ~upport rln~ 116~ A upper ~upport ring 1~0 is eo provlded a~ to be inte~rally ~7~

-2~

conne~ted wlth ~he upper end~ o~ the respe~tive ~traiyht be~m ~e~ion~ 116. The upper support ring 120 1~ lnteyr~lly formed wlth a plurality of vertically extending pilla~ eectlon~ 122 each of 5 whioh has a outwardly pro~ecting bend portion l~a.
~dditionally, an upper rla ~eation 1~4 i~ provlded inside the plllar ~eatlon~ 1~2 in such a manner ~ to ~e integrally connected with the pillar ~ection~ 122.
The upper rld ~e~tlon 124 i8 formed at lts central part with a bolt-hole 124~.
The ou~e~ ~nnular resilient sealin~ member ~4 i~
m~de of a ~oamed polyureth~ne ~nd ~o provlded th~t the lower pa~t of the o~ter peripher~l ~e~tlon of the f$1ter medlum 16 ~nd ~he ~upport s~ruc~ure lowe~
~upport ring 116 are embedded in the ~e~ling member 64. I~ 1~ to be noted that the periphe~al ~ec~lon lower part o~ ~he Pil~er medlum 16 1~ in ~ont~t ~nd engaged wi~h the projections 118a, 118b as best seen from Fig. 16~ In moldlng the o~ter sealing member 64, flowable polyu~eth~ne h~ving a r~l~tively h$gh vico~ity 1~ poured into ~ met~ mold loca~ed at a predetermined position in which the filter medium 16 ~nd the ~upport ~truc~ur~ lowe~ support ring 116 are lo~ated in re~pec~ive pred~termined po~ition~. The thu~ poured polyurethane i~ fo~med and thereafte~
solidified~ ~n thls proce~ ince the poured polyureth~ne ls lower ln flui~l~y, th~ projections ll~a, ll~b ~re formed intermittent along the lower support ring 116 ln order that the 10wable 30 polyurethAne c~n b~ ~u~lciently lntroduced ~rom the upp~r ~ide to the lower ~lde b~ the lower ~upport rlng 116. Th~ throu~h-hole~ l~Oa, l~ob are al~o provlded for ~he ~ame pu~poseJ thereby facilitating -~upply of the flowable polyur~th~ne from the upper slde to the lower ~ide of the lower ~upporS ring 116 Thue, the arran~ement of pr~ection~ 118a, ll~b and the through-h~les 120a, l~Ob ~ontributes to facilltatlng the mol~in~ bf the outer eeallng me~ber 6~ and ~o form~tion of the lnteyral 6tructure of the ou~er ~ealing member ~4 in whlch the ~ealing member upper part located on the lower support ring and ~he seallng member lower part loGated bene~th the ~ame are seaurely integral wlth eAch other, thu~
preventlng the ~eallng member 64 from ~eing peeled off from ~he lowe~ ~upport ring 116 while ~voiding falled fluid seal.
The annular resilien~ inner ~ealing m~mber ~6 is made o'f a ~oamed polyure~h~e and so pro~ded that the upper part of the inner peripheral ~ection o~ the fllter medium 1~ ~nd ~he uppe~ portion o~ the ~upport ~tructure pillar ~ectlon~ 122 ~re embedded ln lnner qealing member 6~ will be under8tood ~hat th~
outer peripher~l por~ion of ~he upper rid ~ec~ion 1~4 i~ also embedded in the upper sealing member 66. The lnner ~ealing member ~6 1~ molded ~imilarly to ~he outer sealin~ member 64. It wi~l be under~t40d th~t, ln thls embo~iment, the bent portion 122a o~ each pillar ~ec~ion 12~ embed~ed in the inner sealing member 66 ~ecu~e~ the connection between the ~ealiny member ~6 an~ the support structure 1~0, therehy preventing the ~ealing mem~er ~6 from being peeled of from the support ~tru~ture 110 while avoiding ~iled fluld ~eal.
A8 ~een ~ro~ Flg~ 20 and 21, the filt~r ele~ent 14 iB ~ecurely ~nd ~ealing in~t~lled withln ~he c~ing 12 formed of ~ pla~tic material. The c~in~

~ 2'~

-~4-12 include~ a rectang~lar ~ox-shaped body ~' formed ~t lt~ centr~l part with an air outlet opening 68'a.
: A rectangular box-~haped cover 7~' is enga~ed wi~h the body ~l and ~ecured in po~ltlon by mean~ of bolt~, thu~ inaoeporatin~ the ~dy 68' and the cover 78'~ The body 68' i~ $n~egrally formed with An air lnlet pipe ~over 78'a. An ~ inlet plpe 80' i~
~ecured to the incorpor~ted ~ody 68' and cover 78' ~o that the ln~ide of the inlet p~pe ~0' i~ communicate~
wlth the lnslde of the casing 12 through an openlng 1~8 formed 1~ the ca~ing 1~. The air lnle~ pipe 80' i~ formed by incorporating upper and lower counterparts 80'a, 80'b by means of pre~ ~it~ A
vaauum mo~or or vacuu~-operated act~tor 130 1 mounted on the air lnlet pi~e upper counterpart 80'~
~nd mechanic~lly aonnected to a damper valve 132 adapted to open or clo~e a he~ted alr lntake plpe 134 throu~h whi~h heated air is ~upplied to th~ the air inle~ pipe 80'~
The filter element 1~ 1B e~cured ln po~ltlon ln ~uch a manner that the ~upport ~truat~re upper rid ~ection ~4 i~ forced to a ~tainer l~fi fixed to the body 68' by ~ean~ of a cent~r ~olt 138 pa~in~
through the cover 78' and located in the bolt-hole 124~ of the ~pper ri~ ~ection 124. ~ ~hown, ~he outer sealin~ member 6~ i~ di~po~ed to be ln tlght ~ontact with the lnner ~urface o the ~ody ~' under the actlon of ~ownwardly e~endin~ parts of the cover 7~' and of the air inlet pipe 80'. The inner ~ealing member 66 i5 ln tight contact with the lnner ~urf~ce of the cover 78'. It will be un~er~tood that the ~ilter element 14 can be installed without any trouble even within ~uch a fl~t C~Bir39 12-~25 ~lg. 22 illu~rate~ ~ six~h ~mbodiment of th~
fluld ~ilter (alr ~ilter) accordlng to the pre~en~ -lnven~lon which i~ ain~ to the fi~th embo~lm~nt of Fig~. 16 and 21. In thls embodlmen~, ~he fllter element 14 a~ same aæ in the fi~th em~odim~nt i~
se~u~ely and 6ealln~1y ~i~po~ed within the ca~ng 12.
The casing 1~ con~ist~ o~ the rel~tively 1a~ body 68' fo~med at lts cen~eral par~ with the alr outlet opening 68'a. The gener~lly bowl-like cover 7~' 1~ provided wlth ~he air inlet pip~ 80' is securely mounted on the body 6a' upon tiqhtening th~ ~ol~ 13 eng~ged ~it~l the ret~lne~ 13~ ~ sp~cer mesn~er 15n i8 interpo~ed between the cover 78' an~ the up~er rid ~e~tion 12~ of the filter m~dlum ~upport stru~ure 1~ 110, so that the upper r~d ~ection 1~4 i~ hrou~ht into tight contact with the retainer 136 while providing ~ ~luld tlght ~eal for ~he ~olt-hole 12~.
The outer se~ling member ~4 iP di~posed to ~e in tlght conta~ wi~h the peripheral ~ection of ~he body 2-, 68' und~r the preP,~lng action of th~ lower peripheral ~ection of the cover 7~ ~ ~cc~rdingly, illustr~ted, air ~ucked lnto the alr Ellte~ ~a~lng 1 flow~, for example~ ~long path~ A1, A2 ~nd A3 to be ~ed ~o the en~ine during engine oper~tion.
~ig. 23 lllu~trate~ a ~eventh embodlment of the fluld ~lter ~alr ~llter) flccordlny to the pre~ent inventlon which i~ ~imilar to the ~lxth embodiment of Fig~ ~ with the excepti.on th~t the annular support b~m 112 section And the s~raight ~upport ~eam ~ectlon~ 114 o~ the skeletal filter medium ~upport structure 110' are ~rr~nged to ~e qener~lly flat~
The fllter medium 16 lle~ fl~t on the thus fl~tly arranged beam ~ctions.

. ~~, ~.

~7~

In the thus configurated air filter 10, air ~ucked to the inside o~ the ça~in~ 1~ flow ~lan~
path~ B~ nd B3 to ~e supplied to the englne.
Figs. 24 to 27 lllu~rate an elghth em~odiment of the fluid filter (air fllter) a~cording to the present inventlon. In thi~ e~bodl~ent~ th~ rilter element 14 is ~ecurely ~nd se~llngly disposed within the ca~lng 1~ a~ ~hown in Flg. 1. The fllter medlum 1~ of the filter element 14 1~ ~ener~lly ~ylindrlcal ~o thaS the pleats 18 exten~ pArallel wi~h each other ~o have a fir~t or ~pper end El and ~ second o~ low~r end E2~ The upper end El cQntain~ the edge 30 o~ th~
first inclined w~ll 28 and the upper e~ye of e~ch first bonded ~ect~on ~1- The lower end ~2 contain~
the edge 42 o ea~h ~eaond inclined wall dO and the lower edge of each second bonded ~c~ion ~ hu~, ~he flr3t inclined ~all~ 28 ~re form~d ln cont~ct with the uppec end E~ and the ~econd i~çlin~d walls 40 are ormed in contact wlth the lower end E2. In thi~ emhodiment, each fir~t inclined wall 28 con~i~t~
of an l~o~cele~-tri~n~ular ~ectlon 28a and a generally rec~angul~r se~tlon 28b containlrly the edge 30. It will be unde~tood thAt th~ 6ur~Ace of ~he rectanyular ~eation 28~ i~ lncllned to th~t of the trlangula~ ~eç~ion 28a. Similarly, e~ch ~econd inclined w~ll 40 con~i~ts o~ an lsosceles~~iangular ~ection 40a and ~ generAlly reçt~ngul~r ~¢~lon ~0~, The ~urf~ce of the rectangul~r sectlon 40~ i~
inclined to that of the tri~n~ul~r sec~ion 4na~
Fl~. 26 ~how~ a ~and~type filter m~terial F
~lmll~ to ~h~t of Fig~ 5~ with the exception ~hat the 11ter mAterial F is ~hown up~lde down rela~ive to that of Flg. 5B. Fig. 26 depict~ ~ plea~lng .A

~ 27 p~ttern of the ~ilter m~terial F to 4b~in the fileer m~dium ~ho~n in Fl~ , ln whiah the core~ ~, a'0 a" indiaated by ~he ~olid line~ are depre~ed to form the downwardly-polnting pleats while the ~cores b, b', b" lndicate~ by the ~roken line~ are rai~ed to form the upwardly-pointing ple~t~ A~ illustr~ted, th~ Adhesive S2 i~ applled on ~he ~ront slde Sl ~t the lower continuoua end secti~n 54~ except for the ~ection~ each being put between the ccore~ b, b~.
Addltlonally, the ~dhe6ive S~ i8 ~pplied on the reve~e side S~ ~t the uppe~ continuou~ end sectlon 54b except for the section~ e~ch being put ~etw~n the s~roe6 ~ In this pleating p~ttern of Fig. 2~ t ~ach o~ the score~ ~', a" i~ bent to have fir~t ~nd ~econd portions Pl, P2~ The portion~ Pl, Pl of the Al, ~" deine an iso~celes-triangular ~re~
whlch correspond~ to the iso~cele~-trlangular ~ection 2~a of the first incline~ w~ll 28 of the fil~r medium 16 Ghown in Fig. 25. The portion~ P2, P2 ~
the ~cores a', a" define a rect~ngle-llk~ area Whlch oorre~ponds to the gener~lly triangul~r ~ection 28~
of the Plr~t inclined WAll 28 of the filter medium lg shown ln Fi~. ~5. As ~hown, the portion P2 of the score~ ~', a" l~ ~o ~ormed thAt the ex~n~lon thereo~
25 pa~e~ through a point where ~he ~cor0 a inter~ects the lower edge of the upper continuou~ end se~tlon 54a. Slmil~rly, eAch Of the ~cores ~', b~ i~ bent to h~ve third ~nd ~ourth p~rtion~ P3, P4. The portion6 P3, P4 of the ~cores b ~, ~" def ine an i~oacele~-30 triangulsr area whlch cor~e~pondc to th~ i~o~celes-~rian~ul~r ~ectlon 40a of the ~e~ond in~lined wall 40 of the filter medlum 16 ~hown in Fig, 25. The portion~ P4, P4 oP the scores bl, b" define a lZ7~

--~0 -rectangle-like area which ~orre~pond~ ~o the gener~lly ~ec~ngular ~ec~ion 40b o the ~e~ond lnclined wall ~0 of the filter medlum 16 shown in Flg. ~5~ A6 ~hown in Fig. ~6, ~he portion8 P4 of ~he ~core~ b', b" is ~o formed th~t the exten~ion ~indicated by ~ dotted line) t~ereof p~eG through polnt where the score b inte~ect~ the upper edge of the lower continuous end ~ec~ion 54~ The fllter ~ateri~l F i~ pleat~d along the ~core~ patterned a~
~hown ln ~ig. ~6 to be ~haped a~ shown in Fl~ 27.
The thu~ ~haped filter mate~ial F i~ there~ter formed lnto ~he ann~l~r shape a~ ~hown in Fig. ~5 by bonding the initial end ~nd ~he terminal end of ~ilter materlal ~. AB ~een from ~i~7 ~4, the ~ir~t ~upper) annulAr resilient ~ealing member 64' iB 80 pr~vided that ~he gener~lly rectangular secticn 28b of e~ch flr~t inclined wall ~8 and the radially lnw~rd portion of each flrst bonded ~e~tlon Bl ~e embedded ln the upper ~eAling member 64'~ The upper ~e~ling member 54' extend~ radlally inwardly ~nd par~llel with the upper end El ~f the annul~ er m~dium 16. Addi~ionally, the ~econd ~lowe~) annular resillent ~e~lin~ member 6~ so provided that the genç~lly rectangular ~eation 40b of each ~econd inelined wall 4~ and the r~d1Ally ~utw~rd portion of e~ch ~çcond bond~d ~ectlon Bz a~e em~edded in the lower ~e~ling member 66'~ Th~ lower sealing member 66' exten~ ~adially outw~rdly ~nd parallel wi~h l~wer end E2~ ~B ~hown in Fig. 24, the upper ~e~ling member 64' l~ ~ecur~d through ~ p~aklng 160 to the b~idge 74 by tl~htening a cen~er bolt 16~ engaged wi~h ~ bridge l64 ~ixed in~ide the air outlet plpe 70. The lo~e~ ~ealing member 66' 18 put betwe~n the --2~--outQr periph~?rAl ~9Ct~Onsl of t he hocly 6R and the cover 7~ throu~h a p~ck.lLn~ 160 . ~cco~din~ly, ~ r sucked through ~he Air irll~t piE~ ~0 flow~ a~
indlc~ted by arr~w~ and pa~ffes thr~ugh the ~llt~r elemen~ 14 to be ~upplied throu~h the ~i r ~utlet pip~
70 to the engin~.
Fig-c~ 28 to 30 ~how a varlety of pleating p~t~erns of the filter m~terial F to form ~nnul~r f ilter medium 1~ llke one shown i n ~ ~ g . 2' ~
The pa~tern of Flg~ 2g i~ ~imllar to th~t shown ln Flg, 27 wi~h the excep~ion ~h~ the ~core~ R ', ai~
are omitted while the ~çore n e~tend~ to re~h the lower edge 5~ o~ the filter ma~erlal F.
The pattern of Fig~ 29 iB similar to that ~hown in Fic~ wi~h ~:h~ exceptlon that the s~ores ~, b' and hn are omi'cted and repl~c~d w:Lth s(:ores g, g ' ea~h exten~ing f ~om the f ll~er m~terl~l lowe~ edge 56a to the lower e~ge of the upper continuou~ end s~ction S4b . The scores ~, g 1 de~ine ~n lso~;cele~-trlang~lar area whlch corre~pond~ to the second inclined wa:Ll 40 formed on the top of e~ch pl e~t l 8 .
The pattern of Flg. 30 1~ ~ln~llar to ~ha~ o~
Fig. 27 with ~he exception th~ the ~cores a, a' ~ a"
are replaoed wi~h ~çore~ h, h' each extendin~ from the ~lltec ~n~terl~l upper edge S~ ~o th~ upper ed~e of the lower contlnuous end ~ection S4a. The BCOre~
h, h' defines an i~o~cele~-tri~ngul2lr ~rea corre~pondln~ ~o the flrst inclined wall ~8.
Fig. 31 illustrate~ a nlnth embodlment of the f luid f ilter ~ai~ f llter) accoralng 'co the p~sen~
ln~ntlon. In ~his embodlment~ ~llter medlum lff ~lmllar to tha~ of F.ig~ Z5 ~the elghth em~odlment) i~

'~`' ~z~

~eGurely atta~hed on the skeletal f llter ~nediunn ~upport structur~ 110 similar to th~t of Fi~ (the f lf~h embodlment) ~o form ~he f 11~eK elemen~ 14~ The filter medium l6 of this enlbodlment .i~ q~nerally fru~to-conlcal and 10CA~ed on the generAlly ~rusto-conlcal sectlon 110~ of the s~pport ~tr~ure 110. ~6 se~n, the inner p~ripher~l sec~lon o~ the filter medium l~ at the ~lr~t end E~ i~ embedded in the ~lr~t sealing mem~er 6~' ln whlch ~he top ~ection 19 of th~ ~uppo~t ~tucture 110 1B embedded~ ~h~ outer peripheral ~ec~ion of ~he fllte~ mediu~ t ~he ~econd end E2 ls em~edded ln the second s~alin~
member 6~' in which the bottom peripher~l $ec~ion of the support ~tru~ture ~lo 1~ embed~ed. In thl~
embodiment, the thus configur~ted filter elem~nt l4 i~ se~ured and ~ealin~ly di~posed in the deep bowl-like body ~8' in ~u~h ~ manner ~hat the ~econd ~ealing mem~er 66' i~ in tight contact with ~he inner ur~ace ~f the body 68' ~ The body 68' is provided w~th the ~ir inlet plpe 801. The flat co~er 7~'is det~ch~bly in~alled to the hody ~' by means o~ th~
bolt 150 engayed wlth the ret~iner 136. A~ordingly, ~ir ~ucked into the c~lng 12 ~low~ ~long p~th~
indicated by Cl, ~2~ ~nd C3 to be supplied to the ~nglne, Fig. 32 illu~t~a~e~ ~ ten~h emhodiment of ~he fluld filter ~air fllter) acGording to the pres~nt lnvention whiah i~ ~imilar to the ninth embcdlment of Flg, 31 wlth the exception th~t the annul~r filter 3o medium l~ ormed flAt ~nd ae~urely di~pooed on the ~lat ~ec~lon llO~ of ~he ~kelet~l fllter medium ~upport ~t~u~ture llO to form the filter element 14.
The low~r ~e~tion o~ th~ ~ir~t ~inner) en~ ~l ~ ~he r !I j' :. , , --31~

~nnular fllter Tne~ium 16 1~ securely connected through the fir~t ~eating member ~4' to the inne~
~ect~ on of the ~upport structure 110 . The upper section of ~he ~econd (outer) end E~ of the annular fll~er medium 16 i~ ~ecurel~ ~onnected through the ~ew nd ~ealln~ mem~er 56' to the outer peripher~l section of 'che ;upport ~ructu~e 110 . In the thu~
configurated alr ~llter 10, air sucked into the ca~lng 1~ flows along path~ lndicated by Pl, D2, and D3 a~d 6uppl ied to the englne.
While the ~d~e 30, 42 of the firat or ~econd inclined wall 2B, 40 has been shown and de~ribed ~8 belnq 6trai~ht, it wlll be understood that the edge may be bent upw~dly or downw~rdly upon incre~ing 15 the leng~h of the edge while decrea~ing the length of the ~lr~t and ~econd bonded ~ec~ion~ 2.
~dd~tlonally~ ~t ~ea~t one of the ~lr~t and ~eco~d incliend w~ 2~ 40 may be cut off ~nd therefor covered with the ~ealing member 64, 66~ It will be appreciated th~t the angle formed between the ~lr~t ~nd ~econd ~l~e~ 20a, ~Ob of each pleat 1~ i~
~uita~ly 6elec'cablç depending upon kind and amo~nt of $1uid to be ~iltered, and allow~ble ~pace for the fll~er element, and that an ~dditional seal member 25 may be u~ed ln c~e where ~he seal memb~rs 64, 6~ are fo~med of a m~te~l~l havlng no re~iliency~ Although only air f ilter~ have been ~ho~n and de~cribed a~ ~he embodiment~ ~ccording to ~he p~esent invention, it will be appreclate~ that the principle of the pre~ent inv~ntion is ~pplicable to a variety of filter~ ~ch A~ lubricating oil, hydr~ullc ~luid, and fuel filter~
used in automotlve lnternal combu~tion englne~

Claims (20)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A fluid filter for an automotive engine, comprising a filter element including a pleated filter medium having a plurality of pleats, said plurality of pleats defining adjacent pairs of first and second pleats, each pleat having first and second sides which are integrally connected through a first score line with each other to form an upwardly-pointing pleat portion, the second side of said first pleat and the first side of said second pleat being integrally connected through a second score line with each other to form a downwardly-pointing pleat portion, each pleat side having oppositely located first and second end sections which have first and second edges, respectively, which extend substantially perpendicular to each score line, the first end sections of said first and second sides of each pleat being approached and bonded to each other to form a plurality of first bonded sections, the second end section of said first pleat second side and the second end section of said second pleat first side, of said adjacent pairs of first and second pleats, being approached and bonded to each other to form a plurality of second bonded sections; and at least one of first and second inclined walls, said first and second inclined walls being inclined to said second score line and said first score line, respectively, said first inclined wall being formed between said first pleat second side and said second pleat first side, said first inclined wall having an edge contiguous to the first edges of said first and second pleats, said first inclined wall being integrally connected through a third score line with said first pleat second side and through a fourth score line with said second pleat first side, the third score line connecting an end point of the second score line and a first point lying at border between the first edge of said first pleat second side and the edge of said first inclined wall, the fourth score line connecting the second score line end point and a second point lying at border between the first edge of said second pleat first side and the edge of said first inclined wall, said second inclined wall being formed between said first and second sides of each pleat, said second inclined wall having an edge contiguous to the second edges of said first and second sides of each pleat, said second inclined wall being integrally connected through a fifth score line with said first side and through a sixth score line with said second side, said fifth score line connecting an end point of the first score line and a third point lying at border between the second edge of said first side and the edge of said second inclined wall, said sixth score line connecting the first score line end point and a fourth point lying at border between the second edge of the second side and the edge of said second inclined wall.

2. A fluid filter as claimed in claim 1, further comprising first and second sealing members, said first sealing member being so disposed that a portion of said plurality of first bonded sections is embedded in said first sealing member, said second sealing member being so disposed that a portion of said plurality of second bonded sections is embedded in said second sealing member, remaining portion of each of said first and second bonded sections being exposed to fluid to be filtered.

3. A fluid filter as claimed in claim 2, wherein said first and second sealing members are made of a material having a resiliency.

4. A fluid filter as claimed in claim 1, further comprising means for forming a first flow path of fluid to be filtered, said first flow path passing between said first bonded sections.

5. A fluid filter as claimed in claim 4, further comprising means for forming a second flow path of said fluid, said second flow path extending between said first and second pleats along length of each pleat.

6. A fluid filter as claimed in claim 5, further comprising means for forming a third flow path of said fluid, said third flow path extending passing through a part of said filter medium, said part including said first pleat second side near and contiguous to said second bonded section, and said second pleat first side near and contiguous to said second bonded section.

7. A fluid filter as claimed in claim 2, further comprising a casing in which said filter element is securely and sealingly disposed.

8. A fluid filter as claimed in claim 7, wherein said casing including at least means for forming a flow path of fluid to be filtered, said flow path passing between said first bonded sections, said means including an air inlet pipe forming part of said casing.

9. A fluid filter as claimed in claim 7, wherein said filter medium is formed annular, wherein said first and second sealing members are annular, said first sealing member extending radially and outwardly, said second sealing member extending radially and inwardly.

10. A fluid filter as claimed in claim 7, wherein said filter medium is formed straight and flat, wherein said first and second sealing members are straight and extending outwardly.

11. A fluid filter as claimed in claim 9, wherein said casing including first fixing means for fixing said first sealing member to the inner surface of said casing maintaining fluid tight seal, and second fixing means for fixing said second sealing member to inner surface of said casing maintaining fluid tight seal.

12. A fluid filter as claimed in claim 9, wherein said annular filter medium is arranged flat so that the first score lines of said pleats are on a flat plane through which an axis of said filter element passes.

13. A fluid filter as claimed in claim 9, wherein said annular filter medium is arranged generally frusto-conical so that the first score lines of all said pleats are on a frusto-conical plane.

14. A fluid filter as claimed in claim 7, wherein said filter medium is formed generally cylindrical so that the first score lines of all said pleats extend parallel with each other, a part of each first bonded section forming a first end of said cylindrical filter medium, a part of each second bonded section forming a second end of said cylindrical filter medium.

15. A fluid filter as claimed in claim 14, wherein said first and second sealing members are annular, said first sealing member extending radially and outwardly, said second sealing member extending radially and outwardly.

16. A fluid filter as claimed in claim 1, further comprising first and second sealing members, said first sealing member being so disposed that a portion of said plurality of first bonded sections is embedded in said first sealing member, said plurality of second sealing members being so disposed that a portion of said second bonded section is embedded in said second sealing member, remaining portion of each of first and second bonded sections being exposed to fluid to be filtered.

17. A fluid filter as claimed in claim 16, wherein the edge of said first inclined wall is embedded in said first sealing member.

18. A fluid filter as claimed in claim 16, wherein the edge of said second inclined wall is embedded in said second sealing member.

19. A fluid filter as claimed in claim 1, 2 or 3, wherein at least one of said first and second inclined walls includes a triangular section defined by said third and fourth score lines, and a nearly rectangular section defined by the edge of said inclined wall, said rectangular section being inclined relative to said triangular section.

20. A fluid filter as claimed in claim 3, wherein said material is one selected from the group consisting of foamed polyurethane and polyvinyl chloride.