Note: Descriptions are shown in the official language in which they were submitted.
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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
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ns
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~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
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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
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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.
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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
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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.
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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
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~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
,
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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
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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
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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
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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
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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 ~
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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
-- 16 --
~ ' ' .. :.
-- ~'22Z~
WH-6502-84 2611G/0037F
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
WH-6502-84 2611G/0037F
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~
-- ~0 --
