Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE FOR ADJUSTING A DRIVING
CXAIN IN A SNOWMOBILE
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a driving device for
a snowmobile which is run on the snow by a crawler belt.
5 Description of Back~round Art
As a driving system for a snowmobile, the driving
syster. using a belt converter has been widely known, as
disclosed in Japanese Utility Model 1aid-Open No. 49-
39124. That is, a driving force of the engine is
10 transmitted to a drive pulley of a belt converter, the
rotation of the drive pulley is transmitted to a driven
pulley through a belt, and the rotation of the driven
pulley is transmitted to a driving sprocket of a crawler
belt through a chain.
In the system disclosed in the aforementioned
Japanese Utility Model Laid-Open No. 49-39124, power is
not effectiYely transmitted since a -?~ ni s~ is not
provided for adjusting a stretching of a chain, or a belt,
for connecting the driven pulley with the driving
2 O sprocket .
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It ls contemplated that as a general procedure for
ad~usting the stretching of the chain, a slipper iB u3ed.
However, where the slipper i8 used, the chain comes lnto contact
with the slipper. Frictlon increase3 and wear is generated.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention i8 to ad~ust the
stretching of the driving chain for the snowmobile without
generating wear or the like. Therefore, the present invention
provides a driving device for a snowmobile, in which an output
of an engine is transmitted to an idle shaft through a belt
converter and a chain is stretched between a sprocket secured to
the idle shaft and a sprocket secured to a drive shaft of a
crawler belt. The driving device is provided with an adjuster
for ad~usting in position the idle shaft around an axis within a
region surrounded by a belt of the belt converter.
According to another aspect of the invention there is
provided a driving device for a snowmobile having a crawler
belt, the driving device comprising:
an engine;
a transmission case connected to the engine;
a belt converter connected to the transmission case, the
belt converter having a drive pulley and a driven pulley, the
drive pulley being connected to the transmission case;
a gear case, a shaft of the driven pulley of the belt
converter being rotatably supported on the gear case;
an idle shaft supported on the gear case;
a drive sprocket connected to the idle shaft, the drive
sprocket moving the crawler belt, the engine driving the drive
_ _ _ _ . _ . _ , . . . . .
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sprocket through the transmission case, the belt converter, the
gear case and the idle shaft; and
an adjuster for pivoting the gear case wlthout
disconnecting the connection between the idle shaft and the
drive sprocket and without disconnecting a connection between
the driven pulley and the drive pulley of the belt converter.
According to another aspect of the invention there is
provided a driving device for a snowmobile comprising:
an idle shaft having a drive sprocket secured thereto;
a crawler belt having a drive shaft;
a chain stretched between the drive sprocket secured to the
idle shaft and a sprocket secured to the drive shaft of the
crawler belt; and
an ad~uster for pivoting in position said idle shaft around
an axis without removing the chain from the drive sprocket.
When the adjuster is rotated, a gear case which
~upports the idle shaft is rotated around an axis (gear case
pivot) within the region surrounded by the belt of the belt
converter whereby the position of the idle shaft moves to finely
20 ad~ust the stretching of the chain. At this time, a fine change
of the distance between shafts of the drive pulley and driven
pulley of the belt converter can be disregarded.
Further scope of applicability of the present
invention will become apparent from the detailed description
given hereinafter. However, it should be understood that the
detailed description and specific examples, while indicating
preferred embodiments of the invention, are given by way of
illustration only, since various changes and modifications
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within the spirit and scope of the invention will become
apparent to those ækilled in the art fror~ this detailed
description .
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BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully
understood from the detailed description given hereinbelow
and the accompanying drawings which are given by way of
5 illustration only, and thus are not limitative of the
present invention, and wherein:
Figure 1 is a side view of the entire snowmobile to
which is applied a suspension device according to the
present invention;
Figure 2 is a perspective view showing inside a body
cover of the snowmobile;
Figure 3 is a plan view of the snowmobile;
Figure 4 is an enlarged side view of the driving
device of the snowmobile;
Figure 5 is an enlarged plan view of the driving
device of the snowmobile;
Figure 6 is a side view showing the suspension device
of the snowmobile and the periphery thereof;
Figure 7 . (right side) is a view taken along Bl of
20 Figure 6, Figure 7 (left side) being a view taken along B2
thereof;
Figure 8 i5 a plan sectional view taken on VIII-VIII
of Figure 4;
Figure 9 is a perspective view showing the adj uster
25 and members in the peripherv thereof; and
Figure 10 is a longitudinal sectional view showing
the adj ustar and members in the periphery thereof .
~ EMBODIMENTS OF THE INVENTION
The embodiment of the present invention will be
3o described hereinbelow with reference to the accompanying
drawings. Turning to Figures 1 and 2, side views of the
entire snowmobile having a suspension device according to
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the present invention are shown. In the snowmobile, an
upper frame 2 is provided at the front portion of a main
frame 1 comprised of a pipe. A floor 3 is provided between
the rear portion of the upper frame 2 and the rear end of
the main frame 1, and a head pipe 4 is mounted on front
ends of the main frame 1 and the upper frame 2.
A lower member 11 of a steering post is inserted into
the head pipe 4. An upper member 13 of a steering post is
connected to the upper end of the lower member 11 through
a universal j oint 12 . A handlebar 15 is connected to the
upper end of the upper member 13 through a universal joint
14. A steering link 16 having a lower end supported on
the snowmobile ~ody and provided swingingly within the
vertical surface is arranged forwardly of and parallel
with the upper member 13. A bracket 17 of the handlebar
15 is connected to the upper end of the steering link 16,
the upper member 13 of the steering post, the handlebar 15
and the steering link 16 constituting a parallel link
mechànism, so that even when a position of the handlebar
15 is moved up and down according to the riding position
of the driver P, an angle of inclination of the handlebar
15 is constantly maintained.
A front ski 21 for steering the snowmobile is mounted
on the lower end of the lower member 11 of the steering
post through links 18, 19 and a bracket 20. The attitude
of the front ski 21 is returned to its straight direction
by means of an urging member 22.
As seen in Figures 2 and 3, a muffler 30 is mounted
on the front side of the head pipe 4. An engine 31 is
mounted on the mainframe 1 at the rear of the head pipe 4.
A battery 32, a transmission case 33, an air cleaner 34,
a carburetor 35, a fuel tank 36 and a radiator reservoir
tank 37 are arranged sideways at the rear of the engine 31
and upwardly at the rear of the transmission case 33,
35 respectively. A body cover 38 covers all these members.
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Further, a radiator pipe 39 in communication with the
radiator reservoir tank 37 is arranged as a whole below a
panel of the floor 3 so as to heat the feet of the driver
P. Moreover, a grip portion 90 pro~ects from }~oth sides
5 of the body cover 38, and a grip portion 91 is also
provided at the rear of the floor 3.
The main structure of the driving device will be
described below with reference to Figures 4 and 5. A
crank shaft 40 of the engine 31 is connected to an output
shaft 43 of the transmission case 33 through gears 41 and
42. A drive pulley 44 of a belt converter is mounted on
the output shaft 43. A driven pulley 45 of the belt
converter is arranged above the drive pulley 44, and a
belt 46 is stretched between the drive pulley 44 and the
15 driven pulley 45.
A shaft 47 of the driYen pulley 45 is rotatably
supported on a gear case 48. An idle shaft 49 is
supported on the other end of the gear case 48, and a
drive sprocket 50 is secured to the idle shaft 49. A
20 driven sprocket 53 for causing a crawler belt 52 to run is
secured to a shaft 51 mounted on the frame, and a chain 54
is stretched between the sprockets 50 and 53.
The gear case 48 is provided with lever portions 48a,
48b. One lever portion 48a is fastened with the engine
25 through a gear case pivot 55. The other lever portion 48b
is fastened with a bracket 56 provided on the upper frame
2 through a chain adjuster 57.
As seen in Figure 9, the chain adjuster 57 has a cam
surface and has a rotational shaft 58 held in a slot 59 of
30 the bracket 56. The chain adjuster 57 is loosened and is
rotated through a predetermined angle while placing the
cam surface of the chain adjuster 57 in contact with a
stopper 57a. Then, the gear case 48 rotates around the
gear case pivot 55 so that the idle shaft 49 moves to
35 finely adjust the stretching of the chain 54.
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Due to the above adjustment, the shaft 47 of the
driven pulley 45 also moves but since the gear case pivot
55 is positioned within the region surrounded by the belt
46, a distance between shafts of the drive pulley 44 and
the driven pulley 45 rarely changes
Gusset plates 86, 86 are provided in the vicinity of
a crossing portion between the main frame 1 and the upper
frame 2, as shown in Figures 6 and 7. The driving shaft
51 is rotatably supported between the gusset plates 86,
86. The sprocket 53 is secured to one end of the driving
shaft 51. A brake disk 8? is secured to the end of the
driving shaft 51 on the side opposite to the sprocket 53,
and a bra3ce caliper 88 is provided, as shown in Figure 6,
in the vicinity of the brake disk 87. A driving wheel 76
is mounted by spline fitting or the like in the
in~P ?~;~te portion of the driving shaft 51, and a gear
portion formed in the outer periphery of the driving wheel
76 is brought into engagement with a rugged portion formed
in the inner surface of the crawler belt 52.
In the suspension device, a cross pipe 61 is
rotatably supported on a shaft 60 mounted in the
in~ te portion between the left and right main
frames l, 1. Fron~ ends of a pair of left and right swing
arms 62, 62 are swingingly supported on the cross pipe 61.
A shaft 63 is mounted in the intermediate portion between
the pair of swing arms 62, 62, and a triangular link 64 is
rotatably supported on the shaft 63.
The front end of a rear cushion unit 65 is connected
to the center of the cross pipe 61 between the front ends
of the pair of left and right swing arms 62, 62, the rear
end thereof being connected to one corner portion of the
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triangular link 64. A shaft 66 is mounted in the
intf~ te portion between the left and right main
frames 1, l. A cross pipe 67 is rotatably supported on
the shaft 66. An upper end of a link 68 is mounted on the
5 cross pipe 67, and the lower end of the link 68 is
connected to the other corner portion of the triangular
link 64.
On the other hand, a collar 69 is provided on the
rear end of the swing arm 62. A shaft 70 is rotatably
10 mounted in the collar 69. A main slide rail 71 laterally
extended is mounted in the central portion of the shaft
70. A pair of left and right side slide rail 72 are
mounted on the outer end of the shaft 70, and guide wheels
73, 74 and 75 are rotatably supported between the front
15 ends, in~ te portions and rear ends of the main
slide rail 71 and the side slide rail 72. The front end
o~ the main slide rail 71 is urged downwardly by a spring
89 .
With the above-described arrangement, when the engine
20 31 is driven, this drive is transmitted to the drive
pulley 80 of the belt converter, as shown in Figure 2.
The drive pulley 81 is rotated through the belt 82
stretched between the drive pulley 8 0 and the driven
pulley 81. The rotation of the driven pulley 81 is
25 transmitted to the idle shaft 83. The rotation of the
idle shaft 83 is transmitted to the driving wheel 76 which
is then rotated through the chain 84 and the driving
sprocket 53, and the crawler belt 52 is moved by the
rotation of the driving wheel 76 so that the snowmobile
3 0 runs .
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As described above, according to the present
invention, there is provided a driving device for a
snowmobile, in which an output of an engine is transmitted
to an idle shaft thr~ugh a belt converter and a chain is
stretched between a sprocket secured to the idle shaft and
a sprocket secured to a drive shaft of a crawler belt, the
idle shaft being adjusted in position around an axis (gear
case pivot) within the region surrounded by the belt of
the belt converter, where~y a change in distance of the
axis of the ~elt converter can be finely adjusted
Accordingly, the stretching of the chaln can be adjusted
without making adjustment of the axis of the belt
conve}ter, and in addition, the adjustment is very easy.
Further, since the pivot pin of the gear case is
positioned internally of the region surrounded by the belt
of the belt converter, the whole system is compact.
Particularly, if the gear case is fastened with the
engine, the variation in distance between shafts can be
minimized in fabrication thereof.
Moreover, since the adjuster according to the present
invention does not contact the chain, friction does not
increase and wear is not produced.
The invention being thus described, it will be
obvious that the same may be varied in many ways. Such
variations are l~iot to be regarded as a departure from the
spirit and scope of the invention, and all such
modifications as would be obvious to one skilled in the
art are intended to be included within the scope of the
following claims
