CA1222644A - Transmission device - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A transmission device having an input shaft supporting a reverse drive sprocket and a plurality of forward speed-change drive gears, and a speed-change shaft supporting a reverse driven sprocket and a plurality of forward speed-change driven gears, the input and speed-change gears being disposed parallel to each other.
The reverse sprocket and forward speed-change gears on each of the input and speed-change shafts are successively arranged in adjacent relation. Slide keys are mounted on the speed-change shaft for selectively engaging inner peripheral edges of the driven sprocket and driven gears on the speed-change shaft for selectively transmitting rotation of the input shaft to the speed-change shaft.

Description

- ~ZZ2~:;44 TITLE: TRANSMISSION DEVICE

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION
The present invention relates to a transmission device for use in a working vehicle such as a riding mower.

DESCRIPTION OF THE PRIOR ART
Riding mowers have two rear wheels and are operated by an operator riding on the mower to run over and cut off yrass. The riding mower requires a transmission such as employed in passenger cars for driving the mower at desired speeds. The transmission in the riding mower has a wide range of gear ratios since the mower is required to move at a low speed while cutting off grass and to run quickly at a considerably high speed when going to an area where grass is to be cut or after having cut the grass.
The riding mower is driven by a single operator, and hence has a small size with reduced longitudinal and transverse dimensions. Accordingly, the transmission ~or use therein is required to be small in size, and also simple in construction to meet a demand for low-cost working vehicles. ûther requirements for the riding mower transmission are that it have sufficient functions and reliability.
One known riding mower transmission is disclosed in U.S. Patent No. 4,103,566 and the disclosed transmission ns 2226~4 ~H-6502-84 2611G/0037F

will be described with reference to Figure 8 of the accompanying drawings.

The prior art transmission has a transmission case 51 with a central input shaft 52 extending transversely therein. A speed-change shaft 53 is supported in the transmission case 51 in a front position therein, the speed-change shaft 53 extending parallel to the central input shaft 52. Drive axles 54, 55 for wheels are also supported in the transmission case 51 in rear position therein, the drive axles 54, 55 extending parallel to the central input shaft 52. A differential gear device 56 is interposed between confronting ends of the drive axles 54, 55. An input driven bevel gear 57 is splined to or otherwise fitted over an axially intermediate portion of the input shaft 52, and is driven by a drive bevel gear on a propeller shaft (no-t shown). A
plurality of drive gears 58A through 58E are splined to or otherwise mounted on the input shaft 52 at one side (righthand side, as shown) of the bevel gear 57 for rotation with the input shaft 52. The drive gears 58A
through 58E are progressively greater in diameter in a direction away from the bevel gear 57 toward a shaft end, the drive gear 58A closest to the bevel gear 57 being smallest in diameter.

Speed-change driven gears 59A through 59E are rotatably fitted over the speed-change shaft 53 and progressively ~reater in diameter in a direction from a shaft end toward a central portion of the shaft 53. The XEROA ,-ELECOPIER 295: O- O-l)O; ~:OI~ AM; c~lrT G3 -~ ; h6 5 ~1222~i49L

gears 59A t.hrough 59E a:re held .in me~h Wi l,h the correspondiny gears 58A througtl 58i~, respecl:ively.
~herefore~ wher~ the ge..~r 57 l.s ~ri.ver~, the sha:Et 5~ is rotated about: its 0~7rl axi6 to ~au~3e the gears 58A through 58E to rotate the c3ear~i 5!~h thrvus~h S~E idly on the sha~t 53. ~he speed~ch~nge ~Iriven years 5~A through 59~ have engacSement slot3 59a irl inner peripheral edge~ thereo.
There are spacer rin~s 59b L~etween the speed~harlc3e drive gears 59A through 59E.
h .reverse d:riven sprocket ~0 is :Lo~.~ely f L t~ed ovex the speecl-change gear 53 :cemotely ~ro~n the speed-chanc3e driven gear~ 5~ throllgh 5gE~ An output gear 61 is ~plined to or otherwlse mc~urlted on the erJd of the shaft 53 and spaced from the reverse driven sprocket 60 with ~ sleeve boss 60a serving as a spacer between the rever~e c~riven gear 60 and ~he Ollt~Ut gea.r 61. The sprocket 6~ is ~pearatively ~oupled by a ~hain 63 to a drive spxocket 62 mounted for corota~ion O~l the Lnput sha~t 52 and spaced ax.ially from the ~evel. gear 57~ The output ~ear 61 is held in mesh with a larger~ n~eter driven gear 65 moun~ed on an end of a final gear 6/~ ~.oosely ~itted ove~ al~ ~nd portion of the input shaft ~2 which exkelldc, oukwardly o~ t.he s~ro~ket 62. ~he .E.inal gear 64 is in mesh wikh a ge~r ~7 on a dierential cage 66 oE the dife.renti~1 gear device 56.
A spee~d chanc3e or shift ~on~rol rnechani~m is operat.ively ~1E~POSeCI between the gear ~9A on the WH-6502-84 ~Z6i~4 2611G/0037F

speed-change shaft 53 and the sprocket 60. The shift control mechansim is composed of a slider 68 axially slidably fitted over the shaft 53 between the gear 59A and the sprocket 60, engagement bars 69 mounted on one end of the slider 68 for radially swinging movement, and a projection 70 on the other end of the slider 68. The slider 6~ is axially movable by a shift fork 71. The sprocket 60 has a recess 60a defined in an inner end surface thereof for receiving the projection 70 therein.
The projection 70 and the recess 60a jointly consititute a dog clutch.

The parts are shown as being in a neutral position in Figure 8. By moving the shift fork 71 to the right in Figure 8, engagement ends of the engagement bars 69 selectively engage in the slots 59a in the gears 59A
through 59E dependent on the stroke o~ axial movement of the engagement bars 69. The shaft 53 is now driven to rotate at a given speed-change ratio, and the rotative power is transmitted through khe gears 61, 65, 64 and the differential gear device 56 to the wheel axles 54, 55.
The engagement bars 69 are allowed to swing radially in the slots 53a defined in the shaft 53. For a reverse movement of the vehicle, the slider 6~ is moved leftward from the illustrated position to enable the projection 70 to engage in the recess 60a. Then, output power from the sprocket 62 is transmitted to the shaft 53,~and rotative power from the shaft 53 is transmitted through the gears 61, 65, 6~, 67 to WH-6502-84 ~2Z~64~ 2611G/0037F

the wheel axles 54, 55, which are turned in an opposite direction to reverse the vehicle.

With the foregoing prior art construction, the forward speed~change gears 59A through 59E are disposed on one axial end of the shaft 53 while the reverse sprocket 60 is mounted on the other axial end of the shaft 53, the shift control mechanism is positioned between the gears 59A through 59E and the sprocket 60, and the output gear 61 on the shaft 53 is disposed outwardly of the sprocket 60 to avoid interference with the shift control mechanism. Therefore, the gears and sprocket on the input shaft 52 are required to be positioned in radial alignment with the gears and sprocket on the sha~t 53. The shafts 53, 52 should be o~ increased lengths to support these gears and sprockets. In addition, the gears 61, 65 are also mounted on the ends of the shafts 53, 52. As a result, the transmission device, including the transmission case 51, has an increased width. Since the gears 61, 65 are displaced toward the ends of the shafts 53, 52, the gear 67 of the differential gear device 56 should also be positioned closely to one end thereof.
This desi0n goes counter to a demand that the wheel axles 54, 55 be equal in length. The conventional layout is poor in space utilization since there is a dead space around the axle 55 near the gears 58A through 58E. The dif~erential gear device 56 is located in axially spaced relation to the gears 58A through 58E, with the bevel gear 57 and other XEROX TELECOPIER 2g5: O- o- no; ~:oo AM: CCITT G3 -~ ; ,Y 8 , ~ F R ~ 3 -, .~ . s t . 1 ~ . 1 2 ~ 7 .`~ 122;~44 ~ "

p~rt~ located adjacent to the cl.;.:l~x:ererlti~l gear devic~ S~.
The transmission ca.se 51 is o an incre~6ed length~
The tran~ml~ ion device o the prior ar~ i~3 th~r~or~
large ln 5ize anl hcsa~y.
S~ EY OE TllE: tqVE~qTIOq With the ~anv2ntlonal shor$.comin~s in ~7iew~ it is an ~ib ject o:~ the present inven t.ion to prvvide ~ tran~mission devic~ which ha~ re31lced trarlsvers~ and longitud:irl~l dimen~ions, is compact ~nd li~htwei.~ht, arld ha~ ~
dif~erentia:l. gear de.vice lc~ated as closel~ to ~he longitudinal cen~ral ~xis o ~ v~hicle as pos~ible for ~riving wheels more e:E~iciently~
To ac:hieve thè a~o~7e ~bject, there is provlded according to t:he present invent1on ~ transmission device compr:i~ing a propeller shart drlva}~le b~r ~n engine, an input shaft disposed ~ubsta.ntia`i ly perpendicularly to the pxopeller sha~t and c3ri.~able ~hereby, the input sha:Et havin~ ~irst and 3eCOnd ends j a xeverse ~ri~re rota~able member ~nd a plural.i ty of b~wAr~ speecl-change drive gears dispo~ed orl the inE)ut ~;haft and succe~slvely arranged ~rom a posi'cior~ near 'ch~ f irst end toward t.he ~3econd endr a ~peecl--change ~3hat di~;po~ed adjacent and ~3ubstantially parallel to the input ~ha:Et and having f irst arJcl second ends and an interme~iate portion r a reverc;e driven ~o~:atable member and a plurality or forward ~peed-ch~nge driLver~ gears di ~3po~ed idly rotatably on the speed~change ~h~t and æuccess ivel y arr~nged :Erom t:he inl:ermedi~a XERC ELE:COPI ER 295 : O- 0 ~ 00, 0: 00 A~l; CC I r r t3s ~ : # 9 F R ~ a ~ 4 1~ 4 ~, . . . .
.

portion tow~rd tt~ s~clc~nt3 e.nd c~:E the spe~.d~charlge fJear, ~h~
reverse driven rotatable member beintJ opeJ:ativel~ ~oupled ~y a eha in tc~ the ~evexse cl.riv~ :r~l:at~b1e me~nber on che input shaf L ~ t:he ~Iriven g~élrs ~ing held in sne~h respective1y wit:h th~ drive ge~rs, an engagement. member mounted cor~tat~bly and axiall.~f slid~bly on the speed-change shat and selective1~Y eng~eable with inner peripheral edge~ of the driv~n rocatabl.e snesnber and th~
driven gear.~i on the speed-change shaf~ fox select.lvely ~ransmitting xot~tive ~ow~r fr~s~ the input sh~ft to ~he ~peed-change shaft, a ~lide ~e~ber rn~unt~d ~ khe speed-change sha~. more cl~ely than the rev~rsa dri~en rotatable m~mber t~ the f ir~t end of the speed~change shaft, ~he enyageme~nt member being supported by the slide member so a~ to ~e rotata~)le with and axia~ly ~l~da~le on the speed-change snat, a mechanisln for rnoving the ~lide member in response to operation of exte.rnal rnean~, and an output ~ember moun~ced orl 'che ~;peea-change shaft at the second end thereof beyond t~-le driven ~ears, for tl~ansmittin~
rotation o~ the speed-challge gear to ~ di~ferenti~l gear device.
The above and other objects, eatures and advant~es of the present invention ~ill becoYne more apparent from the Eollowirlg descriptlon when take~ .in conjunction with the accomp~nying draw:iny~ irl which a prearred ~n~odiment o tha present inven~.ion .i~ shown by way O:L .illustrative example.

:~2~4~

WH-6502 8~ 2611G/0037F

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a side elevational view of a riding mower in which a transmission device of the present invention is incorporated;
Figure 2 is an enlarged cross-sectional view taken along line 2-2 o~ Figure l;
Figure 3 is an enlarged ~ragmentary cross-sectional view of a support construction for a bevel pinion gear for picking up engine output power;
Figure 4 is an enlarged cross-sectional view of the transmission device shown in Figure 2;
Figure 5 is a cross-sectional view of a separate gear on an input shaft;
Figure 6 is a cross-sectional view taken along line 7-7 of Figure 4; and Figure 8 is a cross-sectional view of a prior art transmission device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 schematically shows a riding mower 1 as an example of a working vehicle to which the present invention is applied. The riding mower 1 has a body 2 having a front portion accommodating an engine 3 and a rear portion with a driver's seat 4 mounted thereon. The body 2 supports two front wheels S serving as steerable wheels on the front portion of the body 2 and two rear wheels 6 serving as XEROX TELECOP I EF~ 29~i : o~ `OO: O: O~ AM: cc l T r G:3 ~ 1 7 F 1~ , f 3 ~ 4 ~ 3 ' ~ t . ~ l~, 1 2 13 ~
~2Z2644 ~rlve wheelc; on the rear end o~ ~he body 2~ A hou~ing ~
covering grass cutt:~r bl.ades 7 r 7 I.s attachec~ to a cen~.ral lower portion o ~he body 2. '.rhe gr~ss c:utter blades 7, 7 are ~rranged tan~iemly .In ~ long.ituc~itial cli~ection o~ tAe body ~, ancl dri~en by a bel.t drive mechanl~m 9 composed of a drive pulley mc~un~ed on a ~r~nt end of the engine 3, directional pull.ey, a driven p~lley, a belt trained therearound~ and o~er pulleys ~rld bel~.
The rear ~7heels 6, ~ a.re driYJen throu~h a tran~mission de~ice :L1 by ~ propel.lGr sha~t 10 extending rearwardly rom a rea.r end oE th engLne 3 and inclined sl1ghtly d~wnw~rdly toward a rear end o:~ the propeller sha~t 10, To the rear end of th propel~e~r !~haft lo i5 coupled a gear sha.~t 102 havin~ an inregral hPvel pinion gear 101 for supplying ~n engine power output, as shown in FI~. 2. A transmi~ssion mechanis~ includillg the bevel pinion gear 101 ~nd a differential ~e~r device ~re enclosea by a protective t.r~nsrnissîo~ cas2 111~ The trarl~mission case 111 i5 COnlpO~'ed 0.~ transverciely separate case members 112, 113 joined to-Jether, with t:he ge~r shaft 1~ covered by a cover 114.
Ag clearly ill~s~rated i.n :FIG. 3, the tra~smission case 111 ha~ a hole 103 tllrough wh.ich the bevel pi.nion geax lO:l. extends. The gear ~ha:Et 102, inte~ra:l with the pinion g~ar :L01, is rotatably suppo.rted by a bear.ing 104 disposed in the hole 1030 The bear.i.n~ 104 has an .inner race 104b mounted on the gear s~a~t 1~2 arll~ axial..l.y positi~ned with g , XEROX TELECOPIER 295; 0~ O-OO; û ~O AM, cc:lT-r C~3 ~ ; #12 1~ R o ~ J e ~ u 1 ~ 13 ~ s I
`` i~Z26g~L
r~spect to the gear shaft 102 ~y ~ein~ clamped he~-ts~a~n a st~p lU2~ of the p3 nion t3ear .101 an~ bearing re~ainer 107 ~uch a~ I.ock nu'c thL-ead~wd over tile gear ~ha~t. 102. The bearin~ lD4 al30 has an .,uter xace 104a mounted in the hole 103 and axiall y po~sitioned wit.h respect ~hereto by being clamped b~-tween a shim 106 0!1 a st:ep 105 o~ the transmiss~on ca~;e 111 and a bea~ing ret.~ er 108 .such .~s a lock nut threaded in the hole lD3~ The bevel plnicln gew~r 101 is held in mesh with a be~el gear 14 a~u.stably dependent on the thicknes.s o the sh.im ~0~, the bevel gear 14 being rotatably wuppor~ed :in the tra Ismis..30n ease 111.
For replacing the .shi.m 1(~6 r the l::~earing reta1.nw.r .L08 i~
detached to allow the p.inlon gewar 101, ~he bearing inner race 107 ther~30n~ and the bea.ring 104 t~ ~e pullea out of the hole 103. 'I~hen, the shim 106 iw replaced with a new one through the hole ln3~ Thereafter, the pinivn gear 101, the bearin~ inner rac~w 107 ~hereon, ~nd the bearing 104 are in~erted into the hc~le 103, anc~ then the bearin~ retainer 108 i.s astened in place ~o p:ress ~he beaxing outer xace 104a against the s~ ep 105 through the ~him 106~
As shown in FIG~ 2, an input shaft 12 i~ c~:ispo~ed rearwar~ly o~ the ~ea~ shaft .L02 in a perpendi~ul~r relati~n thereto~ ancl mounted in the tr~n~rnissi~n case 111 transversely ~f ~he ri.ding mower 1~ The input shaf~ 12 has opposite ends rc~tatably suppo.rted hy ~earing~ 13, 13 on the ca~e mernber~ 112t 11.3, respect.ively~ The bevel ~Jear 14, servin~ as a transm:i.s~ion Inechanism .inp~t (~rive~ ear, is XEROX TELEGOPIER ~9b; o- o-on; 0:QI! AM; ccl rT C/3 ~ ; ~iS13 F R ~ 3 -.~ ` 4 ~ 4 . L ~ 2 ~22Z~6~
sp:l ined to or otherwise mou~ ted on an end of th~ input shat 12 which i5 GlC)Se tCJ l.h~ bevel c~ear lO.lr khe b~el gear ].4 meshing with the hevel ~ea.r 101 as clesc:r:ibed above.
q:he input sha~ has ~ rever;e dri~7e sp1 ock~t 15 loc~ted axially adjacer~t: to the gear 14 and remoie from t:he be~riny forward dri~e ge~r assemhly 16 is mo~nted on the input shaft 12 on a side of the reverse drive sprocXet 15 r~lote rom the geax 1.4~ The :Eorwa.rd dri~re gear a~se3nbly 16 comprises five, axially arran~ed, :Eo.r~ard dr~ve gears 161 through 165 in the illustr~:Lt2d emb~diment. The gear 161 which is cl~sest to the spro~ke~ 15 has a smallest diameter, ~nd the other gears a~e pro~ress~vely g:re~ter in diameter in a ~irectiGn a47ay :Erom the sprockel: 15 toward an end of the inpuk .~haft: 1~. The year 155 which is clc)sest to the case membex 112 i~; o:~ a greatest diam2ter. Ir~ the illust:ra~:ed embodirnen~, the gear 161 which is a lst~speed gear is iI~tegrally fc~rmed wil~h the input shal~t 12, and ~he ye~trs .L6~, :L~3, 164, 165 which are ~nd-, 3rd-, 4th- r ~lnd 5th-speed gear~ are splined separately to the i.nput shaft 12.
As shown in PItr. 5~ the 2nd-speed gear 162 has a clear recess 16~a o~ a relative:ly larc3e dia~neter defined in an end surfaf e fac:ing the lst~~speer.~ ge~r 161. When the ~ear 162 .is ~pl ined to the input sha:E t 12 r r i~iny edge5 161a o spline grc~oves 121 de~. inea in the input sha~t 12, ad~acent to the gear 161, are pc:~si tioned in ~he ~le~r rc3ceE;s 16~a. :L'herefore, the ~Jear 162 can ~e held in ~ Z;226~4 W~1-6502-84 2611G/0037F

intimate contact with the gear 161 without being caught by the rising edges 161a (~igure 4).

A rotative output from the propeller shaft 10 is transmitted through the bevel pinion gear 101 and the bevel gear 14 to the input shaft 12 to drive the sprocket 15 and the gears 161 through 165.
A speed-change shaft 17 is disposed behind the input shaft 12 and parallel thereto. The speed-change shaft 17 is longer than the input shaft 12 and has a lefthand (as shown) end 171 rotatably supported by a bearing 18 on a shaft support 112 of the lefthand (as shown) case member 112 and a righthand end 172 projecting laterally beyond the righthand end of the input shaft 12.
The righthand case member 113 has an outwardly bulging portion 113b including a shaft support 113a on which the projecting righthand end 172 o~ the sha~t 17 is rotatably supported by a bearing 18.

A reverse driven sprocket 19 is loosely ~itted over the speed change sha~t 17 on a substantially central portion thereof in alignment with the sprocket 15. A
neutral collar 20 having a smallest diameter is loosely fitted over the shaft 17 adjacent to a side of the sprocket 19 which is remote from the righthand end 172. A
~orward driven speed change gear assembly 21 is loosely fitted over the shaft 17 adjacent to the collar 20 and comprises first through fifth, or 1st - through 5th-speed, successive driven gears 211 through 215. The first driven gear 211 closest to the collar 20 has a largest diameter and is in mesh with ` 1~2~644 W~l-6502-84 2611GtO037F

the smallest-diameter drive gear 161 to provide a greatest speed reduction ratio. The speed through fifth gears 212 - 215 have progressively smaller diameter. The endmost fifth gear 215 has a smallest diameter among the gears 211 through 215, and is held in mesh with the largest-diameter drive gear 165 to provide a smallest speed reduction ratio. The other driven gears 212 - 214 are held in mesh with the drive gears 162-164, respectively. Washers 22 are interposed between the gears 211 - 215, the sprocket 19, and collar 20 on the sha~t 17. The gears 211 - 215, the collar 20, and the sprocket 19 have key slots 211a -215a, 20a, l9a, respectively, defined in inner peripheral surfaces thereof.

In the illustrated embodiment, the 2nd-~pee~
drive gear 162 is slightly wider than the driven gear 212 meshing therewith, and the ~th-speed drive gear 164a has bosses 164 formed on inner peripheral portions thereo~ and projecting axially away ~rom each other to provide clearances between the drive gear 164 and the drive gears 163, 165. This gear arrangement allows the 1st - through 5th- speed driven gears 211 - 215 to be axially spaced wlth certain clearances therebetween.

~ pair o~ axially elongate slide keys 23, 23 are disposed in inner holes in the gears, the collar, and the sprocket on the sha~t 17, the slide keys 23, 23 being spaced 180 ~rom each other. The slide keys 23, 23 are rotatable with the sha~t 17 and axially slidable along the XEROX TELECOPIER 295; n- o-~o; O:t!O AM. C~ITT G3 ~ 16 F R ~ e 7 ~ 3 ' ` ~ . L ~? . L _' L 3 ~
` ~

shEIft 17. 'rhe shcLft :1.7 ha~i ke.y ~30t.s 173~ .1.73 co~perat:irJg with the ~ey slots 211a - 215a, ~na, :L~a i.n lhe gear~
215, the CC~ c!Lr ~0 ~ a.nd th~.~ sprc~c]~:e~t. :L9 :in ax.ially xeceiving the 5:1.i.de keys 23r 23~ F:~G~ 6 show.s t.he relationsilip of tlle k~y ~lots 211cl t 17~ in the ~i.rst dx iven gear 211 -oll~3 the ~;ha~ 17, arl~ ~he sl.icle keys 23. Ea~h of the ~;:I.ide key~ 23~ ~3 ~omp~ es a l:~ody ~31 ha~in~ a length which is sub~3tantially ~he same as the total ax:ial lenqth of the g~ars 21~ - 211, the colLar ~!U, and the sprocke~ 19 an engagemen~ pro jee~t.i~n 232 pxo ject:ing rat~ially outt,7ardly :from a dista:l ~nd oE the ~lide k.ey 23, and a proximal portion 233 projectiLlg radially outwarclly fro~ ~ proximal end o~ the body 23~ The proxirnal port.ion 233 .is in~erted i.n a recess it'S ~n end 2~:1. o.~ a slid~:L 2~ rot;ata~le with the shaft 17 arld axially ~litlably rittecl over the shaft 17~
~he proximal porkio~ 2~3 is pivot:ably supported by a pin 242 on the slider 21'1, so that khe body 2~1 will be angularly mo~abl~ t.o~7ard ancl awi~y f rc~n ~.he s~laf t 17 in the radial direct~on. The slider 24 ha~ ho1.low c~yl.irl~erica1 portions '2~3r 2~3 prvject;.ng ra~ ally outwardly in diametrit.~ y vppvsite rela~.it~n ~ ~om a centJ~l po:ction or' the slider 24. The cylint~r.i.c~1. port.iorls 243, ~43 have openings 244, 244 deined in lower :Lrollt walls thereof ~nd in which the:te are ~r~ly mvvab1y di~;posed exterlsions 234, 234 from the proximal po.rtions ~33, 233 o:E t he slide keys 23 t 23. Bal~ 2~6 r 24~ normally urged r~.}dia.l.3.y inwardly 1:~y ~ring~ 2~5, ~15 are itted in the cy:lint,lrical por'cions ~ 14 ~

XEROX TELECOPIER 295: O-- O~OO; O:OO AM; cclTr G~'3 -~ ; #17 F F~ t 1 ~ e ~ q / 4 ~ . l 7 1 3: ~ 5 .~ .
j ~2226~9~

243~ 243 and helc~ aga.inst l;he ex~ensi.c~:ns ~34, ~34, re~.pe~tively. ~"ne exterlsi~ n~ 234, 234 a~e ther~fore normally ur~ed re~.ili.ently radially inwardly t~ c~u~;e I:he distal proje~tions ~3~, 232 to be lited radially o~w~rdly resiliently~ Stop~ ~47 are. f~ter3ed to ~he cylindrical portions 243 ~or the spring~ ~45, ~45 D
The slider ~4 ha~ an annular gr~o~Je ~49 de~ined in an c~uter peripheral su:rf ac~* o ar~ . end oE the ~lider 24 . Pins 252 ~only one ~howr3 in F~ S. 2 and ~I) mounted O.fl aista1 ends of legs 251 o:E a shi:c oxk 2S ~nga~e in the annular groove 24~ e ~hi~t fo:rk 25 ha~ a l~roximal port:ion 253 fastened t~ a support shaft 254 whlch can be ~perat~d by an exte~na:l shi~t c~ntro:L mechanism such or example ~s a gear ~hi~'c lever.
Orive pow~r ~rorn the drive ge~.-rs ~51 - 1~5 ~lld th~
sprocket 1~ is transmitted to t~e driverl ~ears ~ 215 and the sp~ocket 19 l:~ut ' :n a n~utral ~ear position, 'che gears ~ 21:~ anc~ the sprocke~ 19 r~?~ate iclly on ~he ~haft 17. 'rhe il.l.u.s~La~ed gear p~ition .is a 5th-speed positic~n in whi.ch the ~;peed reduction ratit~n is the smallest. In thi.s po~ition, th~ pL~je~tivn~; ~32 v:E the slid 3ceys 23 engage .in the key slvt~; ~15a in the f i~th driYen gear 2.15, allow.ing drive power r~ be t.ransmitted rom the d.rive~ geax 165 to the speed-change cJear 17 to ro1:ate the sarne at a high ~;peed. ~he o'cher gear~ 214 ~nd the sproc~ket ~!3 rotat:e idely on the shaf t 17 ~ince they ~re not: in encJ~gement with t.he slide keys ~3. ~heD the -- lS --. , .

XEROX TELE~OPIER 2~3~i; o-- n-oo; o:ou AM; cclTr ~i~3 ~ 18 FRI~ F~ p3,1' 4,J:1 `S~. 113, 1~ 13:56 . ~ .~

2~264~L

6hi~t fork ~5 is t:lirned clo~J;wi~e upon r~tat.;.vrl of the support ~ha~t 254, ~h~ s:Lictel- 2~ moved to t..he right ~r the shaft 17, and .~lant ~;u3~E~qce~ 23~a ~ tsle prc)jectiorl~
~3~ of the ~lide key~ '23 sl.ide radially lnwardl~r agaillst the washe~s 2~ to enable the prv~e;~ti.ons 232 to move radially inwardly a~ainsk t..he .resilierlt fo.rces o:l~ the ~prings ~45. I~s the project.ions ~32 r.i,~e over the washers 2Z into the rlext ~ey slc)ts 21s'ar a next gear position or 4th-speed gear posi~ion is se} ected. Çontinued r ightward movemerlt of the slid~r .24 cau~.es the pro jections 232 t o move ;ue~c:es~;ively throllgh ~he key ~lots 213a :~lla until f inally the p.ro jections 232 enyage i.n the key ~lo,' s 20a in the neutral collor 20, whereuporl drive F,ower frc~rn the sha,L
12 the sh~ft 3 7; C~ cut. oE. When the sh.ift fork ~ is moved in ~n opposit e direct:iorl, slant surfaces 232b oE ~he projections 232 sl ic~e against the washers 22 to cause the projections 232 to move radi.ally inwardly over tne washers 2~ into desired ones c~f tile key sl~t: s 211a - 21Sa to select one o:E the 1st thrc)ugh 5 t.h ~E~eeds . Upc n ~urther rightward movement o~ the pro jec~ ic)rls 2~ rorn ~le nel~ral collar 2û, the projections ~3~ en~JaS~e in the key s~ots 19a .in the r~verse spr~cket 1~, ~nc1 dri~e power i.s now t:ransmitted through the chain 2~ ancl the sprocket 19 to the ~haf~ 17 to rotate the same irl zln opposite direction to move the riding mower 1 backwardl.~
'rhe neutral collar ~0 is supported on khe ~haft 17 ~y at lea.~t olle o t.he wa~hers 22 or~ ax.l~l ends of the collar ~ ' ' .. :.

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20, for example the washer 22 disposed between the collar 20 and the driven sprocket 19 and having a shoulder engaging in a recess 20b defined in the collar 20. ~s shown in Figure 7, the collar 20 has an inner circular hole having a diameter larger than that of the shaft 17 to define an annular gap between the collar 20 and the shaft 17, the gap corresponding the depth of the key slots 211a - 215a in the gears 211 - 215. If the collar 20 had an inner peripheral shape with key slots as shown in Figure 6, the slide keys 23 would interfere with the edges of the key slots at the time of moving the slide keys 23 to the neutral position corresponding to the collar 20, failing to allow the slide keys 23 to slide smoothly. However, the arrangement shown in Fig. 7 permits the slide keys 23 to slide smoothly to the neutral positon.

A drive gear 27 is mounted for corotation on the shaft 17 ad3acent to the end 171 thereof, and is held in mesh with a larger-diameter gear 281 on an end of an intermediate shaft 28 extending parallel to the shaft 17 on the rear side thereof. The intermediate shaft 28 has a ~inal output gear 282 on an axially central portion thereof, and includes opposite ends 283, 284 rotatably supported by bearings 29, 29 on shaft supports 112c, 113c, respectively, of the case members 112, 113.

The transmission case 111 has a rearward extension llla on which a pair of rear wheel axles 30, 31 are supported parallel to the input shaft 12 and the speed-XEROX TEL.EC:OPIER ~9Fi; O-- o-OI~; C):OO AM: CC:ITT GS - ; fi620 F F~ 11 -t 3 ~ 4 1 l ' ~3 1. 1~ 5 13 1~2Z6~a ~h~nge gear 1~. The ar.lec; 30r 3J. a.re suppo:rted in ~h~
following manner~ rhe case rnetllb~rs :1.12, 113 of t he transrllission ca~ 111 are sepaxiabl~ jc~ir~ed to~ether a~ross a plane lying perpenclicularly to the a~es of t.he axle~, 30, 31. The case memhe:c~; ll2, 11^~ ha~e ir~tegral tu~ular portions ~ d, ~13d, respe~ti~eiy, c~n a rear ens3 I:hereo~
which px~ject awa3ir rom each ot.:her in ~he directibns of l:he axes of the axles 3~ ~ 31. A d:if:~:erQ~tial ge~lr de~ice 33 is disposed axially hetwf!en ~ne axles ~1) ) 31 and in~ludes a differen~:ial cage 331 h~ving an integ:ral gear 332 meshing with the fina.l ou~:put ~ear: ~82 o:E the intermed1ate sh~ft ~%, and integraL sleeves 33S col~front:ing each o~her in alignment with the axe~3 of ~:he axle~; 30, 31 and through which inner en~s of t.:he~ f.lxles 3t), 31 extend respecti~7ely.
~he tubular E~or~ions 11.2dl 113d have be~rilgs 32 mounted in innex ends thereo~ with the s.leeves 33~ rotal:ably supported in the bearings 32. 'ï'he tubular pC~I~tiC)II~; 112d, 113d also have bearing.s 3C, mc~unted in out~r ~nd~ thereo~ ancl direc~ly supporting t~le a~les 3U ~ 3:L rc~ta~: ly therein ~nd ,seal ri~gs 36 mount:ed in the ou~.er ends o:~ the tubular porti~ns 11~d, L:L3d axi.al:l.y out,wardly ~ r.he bearing~ 35. Each o:E
the axles 30, 3:L is t~erefore support ed ct~C t w~ axi~lly spaced loc,ation~ by the tr~nsm.issiori cclse 111 with sufficîently high rigi 3ity.
Pinic~ 334, 33~l are hou~sed in the cliferer!t.ial cage 33.1 and loo~;ely fi.tted o~ter a p;in:iOIl ~s}la:~t 333 ext~nding centrcllly thrvul3h the àiff~.ren~.ial cage 331. The pinions 12Z;~69L4 334, 334 are held in mesh with side gears 301, 311 mounted on the contronting ends of the axles 30, 31. Therefore, rotative power from the shaft 17 is transmitted through the gears 27, 281, 282, 332, 334, 301, 311 to the axles 30, 31.

In operation, drive power from the propeller shaft 10 is transmitted to the input shaft 12 to drive the sprocket 15 and the gears 161-165, and drive power is then transmitted through a selected one of` the gears 211 - 215 and the sprocket 19, the shaft 17, the intermediate shaft 28, the differential gear device 33 to the axles 30, 31.

In the transmission device as described above, the gear assemblies 16, 21 and the reverse sprockets 15, 19 are located adjacent to each other on the shafts 12, 17. According to this layout, the transmission case 111 has a width much smaller than the width of the conventional transmission case, with only the gear shift components 23, 24, 25 projectable laterally. Therefore, khe overall si~e of the transmission device is reduced.
Since the gears and reverse sprockets are not divided on axially opposite sides on the shafts 12, 17, the shafts 12, 17 are short and are not required to be supported on intermediate portions thereof. The shafts 12, ]7 are therefore of a reduced diameter and weight. Due to the fact that the gear assemblies 16, 21 and the sprockets 15, 19 are disposed closely to each other, the differential gear device can be located in the vicinity of these gears and sprockets. This arrangement is effective to reduce the XEROX TELECUPIER :29~i; o- 0~0(~ 00 AM: cc I-rr ~ 3 t ; h~22 F 1~ c ~ 9 ~ / 3 ~ 14: 13 ``~
`~ i22;~644 loll~i tudlnal cli.men.c;ion oi i~.he caver al:l tran~3mi~;C.ioll clevice, and achieves a more ~c~mpact arlcl light..we.ight cc;l.~.strtlctj.on o ~he o~erall tre~ras~ .ssi.orl clevic e ~hlle al~ e sarn~ time ma.intainir3g a desi. ed gear shi.~tlny ~apa~ .ility. ~.rhe transmis~iorl device o the in~larat.ion has another unctional advantage in that ~cne di:Eere.nt.i;ll ~ear de~7ic e C'~Jl '~e located closely to the longitudir3al axis o:E the v~hi~le.
A:Ltho~h there has ~een d~scribecl what i ~; a~: present considered t:o be the preerred em`~oùiment o~ the present inven~ion, it wil~ e unders~ood tilat the in~en~.iorl may be embo~ied in other .s~ecific ~orln~ wit:hou~ dep~rtin~ ~rom the spirit or essentia~ char~cteristic~ thereof. The present embodiment is thererore t.o ~e c:c~rlsidere~ in all aspects ~s il:l.ustrative~, a~d rlot r~stxicl:ive, The seope of 1~
in~ention is indica~ed ~:y the a~per~ded claim~ rather than by the foregoin~ desc~ript1on~

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Claims (9)

CLAIMS;

1. A transmission device comprising;
(a) a propeller shaft drivable by an engine;
(b) an input shaft disposed substantially perpondicularly to said propeller shaft and drivable thereby, said input shaft having first and second ends;
c) a reverse drive rotatable member and a plurality of forward speed-change drive gears disposed on said input shat and successively arranged from a position near said first end toward said second end;
d) a speed change shaft disposed adjacent and substantially parallel to said input shaft and having first and second end and an intermediate portion;
(e) a reverse driven rotatable member and plurality of forward speed-change driven gears disposed idly rotatable on said speed-change shaft and successively arranged from said intermediate portion toward said second end of said speed-change shaft;
(f) said reverse driven rotatable member being operatively coupled by a chain to said reverse drive rotatable member on said imput shaft,said driven gears;
being held in mesh respectively with said drive gears;
axially slidably on said speed -change shaft and selectively engageable with inner peripheral edges of said driven rotatable member and said driven gears on said speed-change shaft for selectively transmitting rotative power from said input shaft to said speed-change shaft;

(h)a slide member mounted on said speed-change shaft more closely than said reverse driven rotatable member to said first end of said speed-change shaft; said engagement member being supported by said slide member so as to be rotatable with and axially slidable on said speed-change shaft;
(i) a mechanism for moving said slide member in response to operation of external means; and (j) an output member mounted on said speed-change shaft at said second end thereof beyond said driven gears, for transmitting rotation of said speed-change shaft to a differential gear device,

2.A transmission device according to claim 1, wherein said speed-change shaft is longer at said first end thereof than said input shaft.

3. a transmission device according to claim 1, wherein said forward speed-change drive gears are progressively greater in diameter from one of them positioned adjacent to said reverse drive rotatable member toward said second end of said input shaft, and said forward speed-change driven gears are progressively smaller in diamerter from one of them positioned adjacent to said reverse driven rotatable member toward said second end of said speed-change shaft.

4. A transmission device according to claim 1, wherein said reverse driven rotatable member on said speed-change shaft is disposed axially closely to said forward speed-change driven gears with a collar interposed therebetween, said engagement member being engageable with said collar to select a neutral position.

5. A transmission device according to claim 1, wherein said forward speed-change drive gears on said input shaft include an integral gear integral with said input shaft and a plurality of seperate gears splined to said input shaft, said input shaft having spline grooves terminating in rising edges at one side of said integral gear, one of said separate gears adjacent to said integral gear having a clear recess defined in an end surface facing said integral gear and receptive of said rising edges of said spline grooves so as to be intimate contact with said integral gear.

6. A transmission device according to claim 1, including a drive bevel gear coupled with one end of said propeller shaft, said input shaft having on said first end thereof a driven bevel gear held in mesh with said drive bevel gear.

7. A transmission device according to claim 6, including a case accommodating at least said input shaft therein, said case having a hole through which said drive bearing on said gear shaft, said bearing having an inner race mounted on said gear shaft and an outer race disposed in said hole, further including a shim interposed between an axial end suface of said outer race on the side of said drive bevel gear and a surface defining said hole and confronting said axial end surface.

8. A transmission device comprising:
(a) an input shaft;
(b) a transmission gear mechanism;
(c) an output shaft operatively coupled to said input shaft through said transmission gear mechanism;
(e) a pair of axles extending in opposite directions from said differential gear device;
(f) a transmission case housing therein said input shaft, said output shaft, and said axles in parallel relation to each other;
(g) said transmission case being composed of two case members separated by a plane lying substantially perpendicular to axes of said axles; and (h) said case members having respective tubular portions projecting away from each other along said axes of said axles, said axles being supported by said tubular portions, respectively.

9. A transmission device according to claim8, wherein each of said axles is supported at two axially spaced locations by one of said tubular portions of said case members.