Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a tractor in which
the power of the engine is delivered to a propulsion system and
to a PTO (power take-off) system.
Tractors of this type usually comprise a main shaft
rotatable by enginè power, speed change means provided on one
side of the main shaft for the propulsion system and another
speed change means provided on the other side thereof for the
PTO system. These speed change means are each of the gear type
in which speed changes are effected by meshing engagement and
disengagement between gears. When such gear type speed change
means are incorporated in tractors which are adapted for various
uses, frequent speed changes cause damage to the gears, which
then become noisy during engagement or become no longer smoothly
engageable. Additionally the main shaft must be provided with
the speed change gears for the propulsion system and those for
the PTO system. The transmission system therefore has the dis-
advantage of requiring an increased number of parts. Furthermore ~
tractors usually include secondary speed change means for the -
propulsion system, so that the main clutch provided close to the ~ :
engine must be temporarily disengaged every time the primary
or secondary speed change means is to be operated for a speed
change. This interrupts the operation of the PTO system,
possibly causing great inconvenience.
The main object of this invention is to eliminate the
foregoing disadvantages of the prior art tractors and to provide
a tractor in which a multiplicity of speed changes required for
the propulsion system of tractors are readily and smoothly
available with the use of the smallest possible number of speed ~;
change gears and therefore at a reduced cost, the propulsion
system being adapted for the speed changes without the need for
interrupting the operation of the PTO system so that the tractor ~ ~
can fully perform the desired functions. ~ -
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Accordingly, the present invention provides a tractor
of the type in which engine power is transmitted to a propulsion
system and to a power take-off (PTO) system the tractor compris-
ing, a main shaft having a plurality of power transmitting gears
and adjusted to be~rotated by engine power delivered thereto,
first speed change means of the hydraulic clutch type provided
for the propulsion system and disposed on one side of the main
shaft, said fi~rst speed change means having gears meshing with
gears on the main shaft, second speed change means of the gear
type provided for the PTO system and disposed on the other side
of the main shaft, said second speed change means having gears -
meshing with gears on the main shaft, at least one of the gears
on the main shaft being adapted to transmit power to the hydraulic
clutch type speed change means and also to the gear type speed
change means, secondary speed change means coupled to the
hydraulic clutch type speed change means, and differential means
coupled to the secondary speed change means.
Since at least one power transmitting gears is
serviceable for driving the hydraulic clutch type speed change
means and the gear type change means, speed changes can be
effected with a smaller number of parts such as gears than when
these means are individually driven. This is advantageous also
to quality control.
Further because the hydraulic clutch type speed change
means and the gear type speed change means are provided on the
opposite sides of the main shaft, with the propulsion system
made hydraulically controllable, the tractor can be rendered
smaller in longitudinal dimension and compacter in construction
than when the propulsion system is also provided with gear type
speed change means which requires a gear shifting space for speed
changes. The multi-step speed changes required of the tractor
can be hydraulically afforded with ease and smoothness by the -~
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combination of the secondary speed change means and the hydraulic
clutch type speed change means. Moreover the hydraulic clutch
type speed change means provided for the propulsion system
allows the propulsion system to be operated at varying speeds
without disengaging the main c~utch provided for the engine.
Thus the PTO system can be maintained in operation, with the
result that the device driven by the PTO system is continuously
usable to ensure convenience or safety.
The invention will now be described in more detail,
by way of example only, with reference to the accompanying
drawings in which: -
.
Fig. 1 is an overall side elevation showing a tractor
according to the invention;
Fig. 2 is a diagram showing the power transmitting
system of the same; -
Fig. 3 is a side elevation in section showing the
interior of the tractor body in detail;
Fig. 4`is a view in section taken along the line 4-4
in Fig. 3;
Fig. 5 is a side elevation in section showing a second
embodiment of secondary speed change means;
Fig. 6 is a side elevation in section showing a third
embodiment of secondary speed change means;
Fig. 7 is a side elevation in section showing a fourth
embodiment of secondary speed change means;
Fig. 8 is a side elevation in section showing an
intermediate case provided with a traction starter; -
Fig. 9 is an overall diagram illustrating another
embodiment of the traction starter;
Fig. 10 is an overall diagram illustrating another
embodiment of PTO speed reduction means; and -
Fig. 11 is a fragmentary view in section showing
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another embodiment of PTO hydraulic clutch means.
With reference to Fig. 1 showing the overall appearance
of a tractor and to Fig. 2 schematically illustrating a power
transmitting system for a tractor propulsion system and for a
PTO (power take-off) system, the tractor includes a body 1, a
pair of front wheels 2, a pair of rear wheels 3, an engine 4
mounted in the body 1 near its front portion, a primary speed
change case 5 having at its front portion a clutch housing 6
joined to the frame of the engine 4, an intermediate case 7
joined to the rear portion of the primary speed change case 5,
and a secondary speed change case 8 joined to the rear portion
of the intermediate case 7.
With the intermediate case 7 held between the primary
speed change case 5 and the secondary speed change case 8, the
cases 5, 7 and 8 thus joined together provide the frame of the
tractor.
A primary speed change mechanism 9 housed in the
primary speed change case 5 comprises hydraulic clutch type speed
change means 10 for the propulsion system and gear type speed
change means 11 for the PTO system. PTO hydraulic clutch means
12 is positioned to the rear of the PTO speed change means 11
and housed in the primary speed change case 5. Super-speed
reduction means 13 housed in the intermediate case 7 is disposed
to the rear of the speed change means 10 of the hydraulic clutch
type. Secondary speed change means 14 of the gear type is
positioned to the rear of the speed reduction means 13 and -
housed in the secondary speed change case 8. Rear wheel
differential means 15, which is housed in the case 8, drives the
rear wheels 3 through terminal speed reduction means 16. A pair
of brake means 17 for the rear wheels is provided to brake a pair ~`~
of opposite differential yoke shafts. Hydraulic means 18 for
lifting and lowering a working implement is mounted on the
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secondary speed change case 8 as if coverlng the case 8. P'L'O
speed reduction means 19 is housed in the intermediate case 7 and
is positioned to the rear of the PTO hydraulic clutch means 12.
Indicated at 20 is a power transmitting system for the PTO
system, and at 21 an engine clutch housed in the clutch housing
6. A clutch pedal 22, which is provided on one side of the
primary speed change case 5, is depressable by the foot to
engage or disengage the clutch 21 through a link operating
member 23.
A main shaft 24 which is coupled to the engine 4 by
way of the clutch 21 is rotatable by the engine power when the
clutch 21 is in its engaged position.
In the illustrated embodiment, the hydraulic clutch
type speed change means 10 is provided on the upper side of the
main shaft 24, and the gear type speed change means 11 on the
lower side thereof to constitute the primary speed change
mechanism 9. The interior arrangement of the embodiment is
illustrated in Fig. 3 in greater detail. ;
With reference to Fig. 3, *he main shaft 24 coupled
to the engine 4 extends rearward through a partitlon 25 in the
case 5 and through the front wall 26 of the case 7 and is
rotatably supported by a pair of bearings 27 on the walls 25, 26.
A plurality of (i.e. five in Fig. 3) power transmitting
gears 28, 29, 30, 31, 32 are fixedly mounted on the main shaft
24 and spaced apart axially thereof as specified. Of these
gears, the front gear 28 serves only as a gear for giving a
fourth PTO speed, while the rear gear 32 serves exclusively to
give a reverse running speed. The remaining three gears give
first to third speeds both for the hydraulic clutch type speed
change means 10 and for the PTO speed change means 11.
The gears 28 to 32 are fixedly splined to the main
shaft 24. The gear 28 for the fourth PTO speed and the gear 29
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for a first forward running speed and a first PTO speed are
adjacent to each other. The gears 30, 31 for second and third
forward running speeds are adjacent to each other as positioned
in the middle of the axial gear arrangement. As already stated,
these gears 30, 31 serve also to give second and third PTO
speeds. The gear 32 for the reverse running speed is positioned
to the rear of these gears.
The speed change means 10 and 11 are arranged above
and below the main shaft 24 in parallel therewith as illustrated.
The speed change means 10 of the hydraulic clutch -
type comprises a clutch unit 34 and another clutch unit 35
mounted on a clutch shaft 33 serving as a running counter shaft,
the clutch unit 34 being composed of a first forward speed
assembly and a third forward speed assembly disposed side by
side, the clutch unit 35 being composed of a second forward speed
assembly and a reverse speed assembly similarly arranged side by
side according to the illustration. The clutch shaft 33 is
positioned above and parallel to the main shaft 24 and supported
by a pair of front and rear bearings 36. As apparent from Fig.
3, the clutch shaft 33 extends toward the front into the clutch -
housing 6 through the partition 25 of the primary speed change
case 5 and rearward into the intermediate case 7 through the
front wall 26 thereof.
The clutch pack 34 including the first and third
forward speed assemblies is identical in interior construction
with the other clutch pack 35 including the second forward speed
and reverse speed assemblies except that gears 37 to 40 have
different diameters, so that one clutch pack 34 will be described
for illustrative purposes. With reference to Fig. 3, a trans-
mitting member 41 has cylinder portions 42, 43 joined together
end-to-end and is fixedly mounted on the clutch shaft 33 by a
key 44 in the illustrated embodiment. Actuators 45, 46 slidably
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fitting in the cylinder portions 42, 43 respectively are biased
by return springs 47, 48 provided on the tubular boss portion of
the transmitting member 41. Clutch plate mounts 49, 50 integral
with the gears 37, 38 surround the return springs 47, 48 and
extend into the cylindrical portions 42, 43 respectively. A
plurality of hydraulic clutch plates 51, 52 are provided between
the mounts 49, 50 and the cylinder portions 42, 43 of the
transmitting member 41. The clutch plates 51, 52 are interposed
between the actuators 45, 46 and support rings 53, 54 attached
to the cylinder portions 42, 43 and opposed to the actuators
45, 46.
The first and third forward speed gears 37, 38 are
made idly rotatable by needle bearings 57, 58 on sleeves 55, 56
loosely mounted on the clutch shaft 33 according to the illus-
tration. The gears 37, 38 are in mesh with the gears 29, 30 on
the main shaft 24 respectively at all times.
The other clutch unit 35 for giving the second forward
speed and reverse speed includes a transmitting member 61 having ; -
cylinder portions 59, 60 and keyed to the clutch shaft 33 as at `
62. Actuators 65, 66 slidable against the action of return
springs 63, 64 fit in the cylinder portions 59, 60.
The gears 39, 40 are integral with clutch plate mounts
67, 68. A plurality of clutch plates 69, 70 provided between
the mounts 67, 68 and the cylinder portions 59, 60 are interposed
between support rings 71, 72 and the actuators 65, 66 so as to
be clamped therebetween.
The gears 39, 40 are made idly rotatably by needle
bearings 74, 75 on sleeves 56, 73 loosely mounted on the clutch
shaft 33 according to the illustration. The gears 39 is in mesh
with the gear 31 on the main shaft 24 at all times, while the
gear 40 is operatively related to the year 32 on the main shaft
24 by an unillustrated intermediate idle gear.
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The clutch units 34, 35 arranged side by side on the
clutch shaft 33 are held by thrust restraining members 76, 77 at
the opposite ends of the arrangement and an intermediate thrust
restraining member 78.
Indicated at 79 to 83 are circumferential grooves
individually independently formed in the front end portion of the
clutch shaft 33 for passing working oil and cooling oil through
the speed change means 10. These grooves 79 to 83 are in
communication with oil channels 84 to 88 extending axially
through the clutch shaft 33 independently of each other. Of
these oil channels, the channel 84 has a terminal end extending -
diametrically through the shaft 33 into communication with the
interior of the cylinder portion 42 for the actuator 45. The oil
channel 85 is in communication with the cylinder portion 43 for -
the actuator 46, the oil channel 86 with the cylinder portion 59 -
for the actuator 65, and the oil channel 87 with the cylinder
portion 60 for the actuator 66. To lubricate or cool the clutch
plates 51, 52, 69, 70, the remaining oil channel 88 is in
communication with the corresponding cylinder portions. Oil
channels (not shown) are formed in an upper portion of the
partition 25 of the primary speed change case 5 to feed oil to
the channels from control valves.
Fig. 3 further shows brake means 89 for preventing the
momental rotation of the clutch shaft 33. The brake means 89 is
disposed within the clutch housing 6 at the front end of the
clutch shaft 33. The brake means 89 comprises a disk 90 mounted
on the clutch shaft 33, a seal cap 91 covering the circumferential
- grooves in the shaft 33 and fitting in the partition 25, a cover
92 for the seal cap 91 and a slidable ac-tuator 94 accommodated
in the cover 92 and biased toward the disk 90 by a spring 93.
Every time the hydraulic clutch type speed change means 10 is
brought to its neutral position, the drain oil is fed to the
0834g2
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disk 90 for cooling.
The PTO speed change means 11 of the gear type,
positioned below the main shaft 24, has the following construction
With reference to Fig. 3, a PTO speed change shaft
95 extends between the partition 25 of the primary speed change
case 5 and an annular wall 96 and is rotatably supported by a
pair of bearings 97 on these walls, the annular wall 96 being in
the form of a projection and positioned at a longitudinally
intermediate portion of the primary speed change case 5. Midway
between the bearings 97, the shaft 95 has a large-diameter or
enlarged portion 98 formed with a meshing portion 99 on its
outer periphery. The shaft 95 includes small-diameter portions
adjoining the enlarged portion 98 and carrying a pair of front
and rear freely movable sleeves 101, 102 with thrust members 100
provided between the enlarged portion 98 and the members 100.
The sleeves 101, 102 have meshing portions 103, 104 on the outer
peripheries of the opposed ends thereof. A fourth PTO speed
gear 105 is fixedly splined to the sleeve 101 and is in meshing
engagement at all times with the gear 28 on the front end of the
main shaft 24. A first PTO speed gear 106 adjacent the gear 105
and always meshing with the gear 29 on the main shaft 24 is
loosely mounted on the sleeve 101 and has a meshing portion 107.
.
A second PTO speed gear 108 fixedly splined to the other sleeve
102 is in mesh with the gear 31 on the main shaft 24 at all ~
times. A third PTO speed gear 109 adjacent the second PTO speed -
gear 108 is freely movably mounted on the sleeve 102 and is in
mesh with the gear 30 on the main shaft 24 at all times. The
gear 109 has a meshing portion 110.
Thus it is seen that the first and fourth PTO speed
gears 106, 105 are freely rotatably juxtaposed on the speed
change shaft 95 on one side of the enlarged portion g8 thereof,
and the second and third PTO speed gears 108, 109 are freely
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rotatably mounted on the shaft 95 side by side on the other side
of the enlarged portion 98, the first and third PTO speed gears
106, 109 being opposed to each other longltudinally of the
shaft 95. A pair of coupling sleeves 111, 112 slidably splined
to the enlarged portion 98 are formed on their inner peripheries
with meshing portions 113, 114 respectively at the outer ends
of the pair.
Fig. 3 shows that the speed change shaft 95 is dis-
posed below and in parallel to the main shaft 24. Of the power
transmitting gears 28, 29, 30, 31, 32 on the main shaft 24, the
gears 29, 30, 31 thus operate to drive both the hydraulic clutch
type speed change means 10 and the gear type PTO speed change
means 11. The primary speed change mechanism 9 incorporating ~ -
the three shafts is accommodated in the primary speed change
case S containing a lubricant.
The hydraulic clutch means 12, provided to the rear
of the PTO speed change means 11, is disposed between the speed
change shaft 95 and an output transmitting shaft 115 in Fig. 3.
Fig. 3 shows a clutch body 116 fixedly splined to the
shaft 95 and including a bowl-like cylinder portion 117 and a -~
tubular boss portion 120. A slidable actuator 118 is fitted in
the cylinder portion 117. A clutch mount 119 has a bowl-like
portion extending into the cylinder portion 117 and surrounding
the tubular boss portion 120.
The output transmitting shaft llS ls supported by a
bearing 121 fitting in the tubular boss portion 120, is in
alignment with the shaft 95 and extends rearward through the
front wall of the intermediate case 7. The clutch mount 119 has -
a tubular boss portion 122 fixedly splined to the shaft 115 and
supported by a bearing 123 on the front wall 26 of the inter-
mediate case 7. The cylinder portion 117 of the clutch body 116
has a support ring 124 at its open end. A plurality of clutch
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plates 125 are interposed between the ring 124 and the actuator
118 as accommodated in the space defined by the mount 119 and ~-
the clutch body cylinder portion 117. The actuator 118, when
slidingly moved against a spring 126, presses the clutch plates
125, which in turn couple the shaft 95 to the shaft 115. When
the oil is drained, the return spring 126 forces the actuator
backward to disengage the clutch.
The super-speed reduction means 13 is housed in an
upper portion of the intermediate case 7. Fig. 3 shows -the means
13 in the form of a unit mounted on a cover 127 for the inter-
mediate case 7.
In Fig. 3, a gear 128 is fixedly mounted on a rear
end portion of the clutch shaft 33. To the rear of the gear
128, the shaft 33 is formed with a meshing portion 129.
A secondary speed change shaft 130 extends across the
front wall 131 of the secondary speed change case 8 and an
intermediate wall 176 thereof and is aligned with the clutch
shaft 33. The shaft 130 is supported by a pair of bearings 132
on these walls and has a front meshing portion 133 formed as
by splining and extending into the intermediate case 7.
A large gear 134 disposed within the intermediate
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case 7 is freely rotatably mounted on the shaft 130 with a journa~
bearing 135 provided therebetween. The gear 134 has at its
front end an internal gear 136 opposed to the gear 128 on the ~ - ;
clutch shaft 33. ^
A clutch gear 137, mounted on the meshing portion 133
of the secondary speed change shaft 130, connects the meshing ~;
portion 129 of the shaft 33 directly to the meshing portion 133.
Alternatively the clutch gear 137, when engaged with the internal
:
gear 136 of the large gear 134, couples the gear 134 to the
meshing portion 133 of the shaft 130.
A super-speed reduction gear 138 comprises a large
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gear 139 and a small gear 140 fixedly mounted on a gear shaft
141 and spaced apart from each other axially thereof. The gear
138 is freely rotatably supported by a pair of front and rear
projections 142, 142 on the intermediate case cover 127. The
cover 127 thus provided with the speed reduction means 13 is
mountable in place, with the large gear 139 in mesh with the
gear 128 on the clutch shaft 33 and also with the small gear
140 meshing with the large gear 134 on the secondary speed change -
shaft 130.
The gear shaft 141 is deviated from the secondary
speed change shaft 130 rightward in Fig. 4 by a distance L,
thereby permitting the super-speed reduction gear 138 to mesh
the large gear 134 obliquely from above and to be positioned at
a lower level, while providing on one side of the cover 127 a
space for the provision of a speed change lever and other parts.
The secondary speed change means 14 shown in Fig. 3
for illustrative purposes is of the gear type and is adapted to
give three secondary speeds.
With reference to Fig. 3, the secondary speed change
shaft 130 fixedly carries power transmitting gears 144, 145,
146 as spaced apart. The gear 144 gives a first secondary speed,
the gear 145 a second secondary speed and the gear 146 a third
secondary speed. A drive pinion shaft 147 disposed below and
in parallel with the shaft 130 is supported by a pair of front
and rear bearings 148 and carries three secondary speed change
gears, 149, 150, 151 between the bearings 148.
The drive pinion shaft 147 is provided at its rear
end with a pinion 152 meshlng with a crown gear 153 of the rear
wheel differential means 15 and is positioned to the rear of the
main shaft 24 substantially in alignment therewi-th.
The shaft 147 is fixedly provided at its intermediate
portion with a sleeve 155 having a splined or meshing portion
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154. To the front and rear of the sleeve 155, the shaft 147 ~ ~ -
freely rotatably carries the gears 149, 151 always meshing with -~
the gears 144, 146 on the speed change shaft 130. The gears
149, 151 are made idly rotatable substantially by freely
rotatable sleeves'156, 157 having meshing portions 158, 159
opposed to each other. The second secondary speed gear 150
slidable on the fixed sleeve 155 affords three modes of coupling
the gear I50 couples the meshing portion 158 of the rotatable
sleeve 156 to the meshing portion 154 of the fixed sleeve 155,
or couples the meshing portion 159 of the rotatable sleeve 157
to the meshing portion 154 of the fixed sleeve 155 or is meshable
directly with the gear 145 on the secondary speed change shaft - : -
130.
Fig. 4 shows means 160 for operating the super-speed
reduction means 13. The operating means 160, disposed on one
side of the intermediate case cover 127, includes a shift fork
rod 161 supported by the front and rear walls of the cover 127
and extending longitudinally of the tractor. A fork lever 163
having an engaging portion 162 and secured to the rod 161 has
a fork portion in engagement with the clutch gear 137. A
support 164 is mounted on the cover 127 at one side thereof. ;~
An operating lever 166 is turnably supported in its upright
position by a ball 165 on the support 164 and has a lower end
engageable with and disengageable from the engaging portion 162.
Extending in parallel with the shift fork rod 161 is
another shift fork rod 167 fixedly provided with a block 169
having an engaging portion 168. A pin 170 mounted on a side
wall of the intermediate case 7 is provided with a connecting ;
lever 172 connected to the block 169 by a universal ball joint
171. The lever 172 or the pin 170 is coupled, through an un-
illustrated coupling link, to a fork lever engaging the
secondary speed change gear 150.
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1083492
Accordingly when the operating lever 166 is inclined
leftward in Fig. 4 into engagement with the portion 162 and then
moved forward or rearward, the clutch gear 137 slidingly moves
forward or rearward. If the operating lever 166 is turned
rightward in Fig.`4 into engagement with the portion 168 and then
moved forward or rearward, the secondary speed change gear 150
can be moved forward or rearward. Thus the two slidable members
separately positioned can be operated by the single lever 166.
Fig. 3 further shows a drive gear 173 fixedly mounted
on the drive pinion shaft 147. A PTO intermediate shaft 174 is
supported by a bearing 177 in a bearing case 175 projecting
into the intermediate case 7 and by another bearing 177 on an
intermediate wall 176 of the case 8. The shaft 174 is sub-
stantially in alignment with the PTO speed change shaft 95 and
is connected by a coupling 178 to a PTO shaft 179 extending
outward from the rear wall of the secondary speed change case 8.
It will now be apparent tha-t the secondary speed
change case 8 also accommodates a three-shaft arrangement in
which the secondary speed change shaft 130 and the PTO inter-
mediate shaft 174 are disposed on the upper and lower sides ofthe drive pinion shaft 147 in parallel therewi-th. The PTO
intermediate shaft 174 and the PTO shaft 179 may be provided as
an integral shaft.
The PTO speed reduction means 19 positioned to the
rear of the PTO hydraulic clutch means 12 is housed substant-
ially in the lower portion of the intermediate case 7.
In the embodiment of Fig. 3, the rear end portion of
the main shaft 24 extends into the intermediate case 7. A speed
reduction gear 183 including a large gear 181 and a small gear
182 integral therewith is freely rotatably mounted by a needle
bearing 180 on the rear end portion which is supported in a
cantilever fashion. The output transmitting shaft 115 of the
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clutch 12 fixedly carries at its rear end a gear 184 always
meshing with the large gear 181 of the reduction gear 183. A
gear 185 secured to the front end of the intermediate shaft
179 is in mesh with the small gear 182 of the gear 183 at all
times. The gears 184, 18 and the gears 182, 185, involving
different reduction ratios, effect a two-step speed reduction.
As seen in Fig. 3, the PTO intermediate shaft 174
freely rotatably carries an intermediate gear 187 by means of
a needle bearing 186. The year 187 is in mesh with the drive
gear 173 on the drive pinion shaft 147. Power takeoff means 188,
when driven by way of the intermediate gear 187, affords a `~
power in synchronism with the rotation of the rear wheels 3 but
independently of the PTO shaft 179.
The power takeoff means 188, which is mounted on the
bottom of the secondary speed change case 8, has the following
construction.
With reference to Fig. 3, a power takeoff case 189 ;
is attached to a bottom portion of the case 8 with unillustrated
bolts or the like. A power takeoff shaft 190 mounted by a pair
of front and rear bearings 191 on the case 189 extends forward
from the case. ~
A power takeoff gear 192, meshing with the inter- -
mediate gear 187 at all times, is idly rotatably mounted on the
takeoff shaft 190 by a journal bearing 193. The main body of
the gear 192 has a plurality of engaging portions 194 arranged ,
at specified spacing circumferentially thereof. In the
illustrated embodiment, the engaging portion is in the form of ;
a hole. A sleeve 195 adjacent the takeoff gear 192 is fixedly
mounted on the shaft 190. A shifter 197 having an engaging
member 196 is splined to or otherwise mounted on the fixed
sleeve 195 axially slidably. The engaging member 196 on the
shifter 197 is in the form of a pin in the illustrated embodi-
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~L08~92
ment and is projectable by beiny biased with a spring 198 at
all times. A plurality of like engaging members 196 are cir-
cumferentially arranged and are axially slidably projected from
the shifter 197 so as to oppose the engaging portions 194.
The embodiment of this invention shown in Figs. 2
and 3 operates in the following manner. When the clutch 21 is
engaged after starting the engine 4, the main shaft 24 is
positively driven, while an unillustrated hydraulic pump
operates, whereby the working oil contained in the primary speed
change case 5, etc. serving also as an oil reservoir is with-
drawn therefrom or fed thereto while being filtered. With the
rotation of the main shaft 24, the clutch gears 37, 38, 39, 40
of the speed change means 10 above the main shaft 24 and the
speed change gears 105, 106, 108, 109 of the speed change means
11 below the shaft 24, meshing with the gears 28, 29, 30, 31,
32 on the shaft 24, freely rotate on the clutch shaft 33 and on
the speed change shaft 95.
All unillustrated change-over valve is then operated
to feed the working oil to the hydraulic clutch type speed
change means 10, thereby operating one of the actuators 45, 46,
65, 66, whereby the running system is given one of the first to
third forward speeds or reverse speed. Further if one of the
coupling sleeves 111 and 112 is slidingly moved by an unillus-
trated PTO speed change lever rightward or leftward in Fig. 3,
one of the four PTO speeds is given to the PTO system.
First, power transmission through the propulsion
system will be described. When the working oil is fed to the
cylinder portion 42 for the actuator 45, the actuator 45 slides
against the spring 47, thereby connecting the first forward speed
30 ~ gear 37 to the transmitting member 41 secured to the clutch
shaft 33 by the hydraulic clutch plates 51, whereby the desired
torque is delivered to the shaft 33 tllrough the gear 29 on the
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main shaft 24 and the gear 37 on the clutch shaft 33 to drive
the shaft 33. When the working oil is fed to the actuator 65
to engage the clutch assembly concerned, the gear 31 on the
main shaft 24 meshing with the gear 39 on the clutch shaft 33
rotates the transmittiny member 61 through the clutch plates 69,
driving the shaft 33 at the second forward speed. When the
working oil is fed to the actuator 43, the gear 30 on the main
shaft 24 meshing with the gear 38 on the clutch shaft 33 rotates
the transmitting member 41 through the clamped clutch plates 52,
driving the shaft 33 at the third forward speed. Further when
the working oil is fed to the actuator 66, the gear 32 on the
main shaft 24 coupled to the gear 40 on the clutch shaft 33 by
way of the unillustrated intermediate gear rotates the trans-
mitting member 61 through the clutch plates 70 and reversely
rotates the shaft 33. Thus with the primary speed change
- mechanism 9, three forward speeds and a reverse speed are
obtained by individually actuating the clutch assemblies incor- ~
porated in the hydraulic clutch type speed change means 10. -
Every time the speed is changed, the drain oil from the clutch
when it is brought to its neutral position may be fed to the
brake means 89 to cool the means 89, hence advantageous. The
brake means 89 mounted on the clutch shaft 33 is also advantageous
in that the shaft 33 can be prevented from rotation due to the
momental torque involved.
When the clutch gear 137 of the super-speed reduction
means 13 is shifted to the left in Fig. 3 by moving the operatin
lever 166 shown in Fig. 4 longitudinally of the tractor to
connect the secondary speed change shaft 130 directly to the
clutch shaft 33, the torque delivered from the speed change meanS
10 as desired is transmitted directly to the secondary speed
change shaft 130. If the clutch gear 137 is shifted to the
right in Fig. 3 to operatively connect the idel gear 134 on the
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~C~83492
shaft 130 to this shaft, the torque resulting from the super-
speed reduction effected by the gear 138 is given to the
secondary speed change shaft 130. The torque thus transmitted
through the means 13 assures smooth gear engagement for the
secondary speed change means 14 of the gear type.
When the torque derived from -the required speed
change is delivered to the secondary speed change shaft 130
whether directly or by way of the super-speed reduction means 13,
the illustrated secondary speed change means 14 produces one of
three speed changes.
Stated more specifically, when the secondary speed
change gear 150 which is rotatable with and slidable on the drive
pinion shaft 147 is shifted to the left in Fig. 3 by moving the
operating lever 166 shown in Fig. 4 longitudinally of the tractor
to couple the meshing portion 158 of the freely rotatable sleeve
156 to the meshing portion 154 of the fixed sleeve 155, the
engagement between the gear 144 on the shaft 130 and the gear
149 on the shaft 147 gives a first secondary speed. If the gear
150 is shifted into engagement with the gear 145 on the shaft 130,
the engagement therebetween gives a second secondary speed to the
pionion shaft 147. When the gear 150 is further shifted to the
right in Fig. 3 to couple the meshing portion 159 of the freely
rotatable sleeve 157 to the meshing portion 154 of the fixed
sleeve 155, the engagement between the gears 146, 151 rotates the
shaft 147 at a third secondary speed.
In this way, the hydraulic clutch type speed change
means 10 of the primary speed change mechanism 9 produces three
forward speeds and a reverse speed and the secondary speed change
means 14 affords three secondary speeds, thereby delivering a
multiplicity of different forward and reverse speeds to the
differential means 15. The torque is given to the pair of rear
wheels 3 via the terminal speed reduction means 16 to drive them.
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(See Fig. 2.)
When the shifter 197 of the power takeoff means 188
in the embodiment of Fig. 3 is shifted to the right in the
drawing, the power takeoff shaft 190 is driven in timed relation
to the rear wheels 3. More specifically it is seen that the
takeoff gear 192 on the shaft 190 is driven by the drive gear
173 on the shaft 147 by way of the intermediate gear 187. With
the shifter 197 shifted to the right in Fig. 3, the engaging
members 196 are in contact with the main body of the gear 192,
compressing the springs 198. The engaging members 196 thus
biased by the springs 198, when brought into alignment with the
engaging portions 194 of the gear 102, engage in the portions 194,
thus coupling the shifter 197 to the gear 102 to rotate the
shifter therewith and driving the shaft 190 with the pinion shaft
147 since the shifter 197 is connected to the shaft 190 by the
sleeve 195. If the drive pinion shaft of the front wheel differe-
ntial means is coupled to the power takeoff shaft 190 by a pro-
peller shaft connected to the shaft 190, the front wheels 2 are
made rotatable with the rear wheels 3. The four wheel-driven
tractor thus provided will have an increased traction and greater
ability to ascend slopes. The power takeoff shaft 190 is of `
course useful for driving an implement attached to the tractor
bottom. The shifter 197, when shifted to the left from the
engaged position, brings the power takeoff means 188 out of `
operation.
The PTO power transmittlng system is used for driving
a working implement attached to the rear end of the tractor.
When the coupling sleeve 111 is shifted to the left
in Fig. 3 to couple the meshing portion 99 of the speed change
shaft 95 to the meshing portion 107 of the speed change gear 106,
the gear 106 which is in mesh with the gear 29 on the main shaft
24 delivers the torque to the shaft 95 at a first PTO speed.
'
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~L083492
When the coupling sleeve 111 is shifted to the right in the
drawing to couple the meshing portion 99 to the meshing portion
103, the shaft 95 rotates at a fourth PTO speed. If the coupling
sleeve 112 is shifted to the left in Fig. 3 to couple the meshing
portion 99 to the meshing portion 104, a second PTO speed is
available. When the sleeve 112 is shifted to the right to couple
the meshing portions 99, 110 to each other, a third PTO speed is
available. Briefly if the coupling sleeve 111 or 112 is
selectively shifted leftward or rightward, the PTO speed change
shaft 95 in the illustrated embodiment is driven at one of the
four PTO speeds since the gears 28, 29, 30, 31 on the shaft 24
are in mesh with the gears 105, 106, 108, 109 at all times.
When oil is fed to the cylinder portion 117 of the
hydraulic clutch means 12 disposed to the rear of the PTO speed
change shaft 95 to actuate the actuator 118, the torque is
delivered to the output transmitting shaft 115 through the clamped
clutch plates 125. The torque is then subjected to speed re-
duction in the PTO speed reduction means 19 behind the clutch
means 12 and drives the PTO shaft 197 through the intermediate
shaft 174.
Fig. 5 shows a second embodiment of the secondary speecl
change means 14.
With reference to Fig. 5, a secondary speed change
shaft 130 is provided with power transmitting gears 144, 146 on
front and rear portions thereof (i.e. on the left and right of
the drawing), the gear 144 being fixed to the shaft, the other
gear 146 being idly rotatable on the shaft. The idle gear 146
is formed with a recessed engaging portion 146a. `
A slidable gear 145 positioned between the gears 144
and 146 and engageable with the engaging portion 146a is splined
to or otherwise mounted on the shaft 130. A drive pinion shaft ~ ~
147 is freely rotatably provided with a first secondary speed - :
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~083492
change gear 149 meshing with the gear 144 at all times and having
a recessed engaging portion 149a. A third secondary speed change
gear 151 is fixedly mounted on the shaft 147 and is in mesh with
the gear 146 at all times. Between the gears 149 and 151, the
shaft 147 further carries a slidable second secondary speed
change gear 150 meshable with the gear 145 or with the engaging
portion 149a. With the embodiment shown in Fig. 5, therefore,
when the gear on the shaft 147 is engaged with the engaging
portion 149a of the gear 149 on the same shaft, the torque is
delivered from the gear 144 to the idle gear 149, driving the
pinion shaft 147 at a first secondary speed. If the gear 145 on
the shaft 130 and the gear 150 on the shaft 147 are shifted
toward each other into meshing engagement, the shaft 147 rotates
at a second secondary speed. Further when the gear 145 on the
shaft 130 is engaged with the engaging portion 146a of the idle
gear 146 on the same shaft 130, the engagement therebewteen gives
a third secondary speed.
According to the embodiment shown in Fig. 5 in which
the two gears 145, 150 are shiftable on the shafts 130 and 147
respectively, the axial length of the secondary speed change means
14 shown in Fig. 3 between the opposed front and rear bearings
can be greatly shortened. Although not shown in Fig. 5, the
drive gear 173 shown in Fig. 3 can be fixedly provided on the
right side of the gear 151 to drive the power takeoff means 188.
Fig. 6 shows a third embodiment of the secondary speed -
change means 14.
With reference to Fig. 6, three power transmitting
gears 144, 145, 146 are fixedly mounted on the secondary speed
change shaft 130 as in Fig. 3~ Always meshing with the gears
144, 146 are secondary speed change gears 149, 151 idly rotatably
mounted on a drive pinion shaft 147. The gear 149 has a recessed
meshing portion 149a, while the gear 151 has a projecting meshing
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~)83492
portion 151a. A gear lS0 slidable between the gears 149 and 151
and mounted on the shaft 147 has a recessed meshing portion 151a
engageable with the meshing portion 149a. When the slidable
gear 150 is shifted into engagement with the meshing portion 149a
of the gear 149, a first secondary speed is available, the
meshing engagement between the gears 150 and 145 gives a second
secondary speed, and the engagement between the portions 150a and
151a gives a third secondary speed. The bearing-to-bearing axial
distance of the speed change means shown in Fig. 6 is intermediate
between that of Fig. 3 and -that of Fig. 5.
Fig. 7 shows another embodiment of each of the secon-
dary speed change means 14 and the power takeoff means 188.
With reference to Fig. 7, an intermediate gear 187 on
the PTO intermediate shaft 174 has a length equal to the distance
over which a slidable secondary speed change gear 150 is slidable
to eliminate the drive gear 173 shown in Fig. 3. When the gear -
150 is shifted in the same manner as in Fig. 3, three secondary
speeds are available. Since a power takeoff gear 192 is in mesh
with the intermediate gear 187 which rotates with the gear 150
irrespective of the position of the gear 150, a power takeoff
shaft 190 can be brought into or out of operation by the engage-
ment or disengagement of a shifter 197.
Fig. 8 shows a traction starter 199 incorporated in
the intermediate case 7. The main shaft 24 is provided at its
projecting end with a slidable clutch gear 200 engageable with
or disengageable from a large gear 134 on a primary speed change
shaft 130. When the clutch gear 200 is engaged with the large
gear 134, with the gear 134 coupled to the shaft 130 by a clutch
gear 137, and the tractor is pulled by another tracting vehicle,
the main shaft 24 can be driven through the secondary speed
change means 14 and the clutch gear 200 to start the engine 4.
Fig. 9 shows another traction starter 199 comprising a clutch
,
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~L0~33492
gear 200 adapted to disengageably engage the main shaft 24 with
the drive pinion shaft 147. The clutch gear 200 of the starter
199 shown in either Fig. 8 or 9 can be shifted by the operating
lever 166 shown in Fig. 4.
Fig. 10 shows another embodiment of the PTO speed
reduction means 19 including another shaft 183a for carrying a
speed reduction gear 183, as distinct from the arrangement of
Fig 3 in which the corresponding gear 183 is mounted on the
extension of the main shaft 24. Although the rear end portion
of the main shaft 24 shown in Fig. 3 is supported in a cantilever
fashion, the rear extremity of this portion may also be supported
by some means.
The PTO hydraulic clutch means 12 shown in Fig. 11
includes a one way clutch 12a. The clutch mount 119 and the
tubular boss portion 122 shown as an in-tegral member in Fig. 3
are separate in Fig. 11 and made rotatable relative to each other
by a bearing 201. The one way clutch 12a interposed between the
mount and boss portion is of the known type to block the delivery
of momental torque to the PTO speed change means 11 while per~
mitting the transmission of torque from the means 11 to the
intermediate shaft 174.
It will be apparent from the foregoing description
that this invention can be embodied variously within the scope
thereof.
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