JP3912387B2 - Snowmobile - Google Patents

Description

  The present invention relates to a snowmobile equipped with a four-cycle engine.

  2. Description of the Related Art Conventionally, in general, a two-cycle engine has been a mainstream engine for small snow vehicles such as snowmobiles. As a characteristic of the two-cycle engine, there is an advantage that the engine structure is relatively simple, lightweight, compact and high power. However, compared with a 4-cycle engine, there are problems such as a large amount of exhaust gas emission, a large noise, and a large vibration.

  As a global trend in recent years, clean, quiet and environmentally friendly engines are required. The engine for snow vehicles is no exception, and a clean and quiet engine is desired. Therefore, a 4-cycle snowmobile engine is being studied.

  In conventional snowmobiles, the body frame is generally configured as a monocoque frame structure, and the engine is mounted in a space sandwiched between a track housing and a front suspension housing formed at the front of the frame (engine mount frame). In the case of a two-cycle engine, the engine is mounted upright in the engine room.

  However, when mounting a 4-cycle engine on a snowmobile in the same manner as described above, the cylinder head becomes larger than the 2-cycle engine and an oil pan is required, which increases the overall height of the engine. It was difficult to mount in an upright state. Moreover, in the case of a four-cycle engine, it is necessary to newly install parts specific to the four-cycle engine such as an alternator, a supercharger, an intercooler, and an oil filter, so the layout in a limited space in the engine room is very It is considered difficult.

  Therefore, as shown in FIG. 7, the engine 202 mounted on the snowmobile 201 is tilted forward so that the total height of the engine 202 can be lowered and mounted in the engine room 206, and the engine 202 is tilted. A device has been proposed in which the above-described components are arranged in a space formed in this way.

However, in a four-cycle engine, the oil pan 238 needs to be positioned at the lowest part of the engine. However, when the engine is a wet sump system, the oil pan 238 becomes large, and as shown in FIG. The problem of interference with the pan 238 arises.
In the case of a snowmobile, the lower part of the engine room needs to be closed in order to serve as a ski that slides on snow, and there is a problem that maintenance such as oil change becomes difficult.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a snowmobile that saves space in an engine room and improves maintainability.

The present invention relates to a snowmobile, which includes a crawler and has a four-cycle engine mounted in an engine room covered with a front cover on the front side of the vehicle body. The front part of the vehicle body frame projects upward from the bottom of the engine room. A front suspension housing formed to accommodate the upper part of the front suspension, and a track housing that accommodates the crawler drive wheels in a shape in which the rear part rises upward from the bottom of the engine room, and a windshield is provided on the front cover near the bar handle In a snowmobile equipped with a four-cycle engine that is configured to operate a steering sled through a steering shaft with the bar handle,
The oil supply system of the four-cycle engine is a dry sump type that includes an oil tank separate from the four-cycle engine disposed in the engine room, and sends engine oil to the oil tank via an oil strainer in an oil pan. The oil pan is disposed close to the bottom of the engine room between the front suspension housing and the track housing, while the front cover is formed in a substantially streamline shape toward the front of the vehicle body more gently than the windshield base. a shape falls, a vaporizer which constitutes the intake passage at a position higher than the upper position of the cylinder head of the four-stroke cycle engine, and while placed inside the windshield base front end portion of the front cover in a side view, wherein the oil strainer is arranged vertically below the vaporizer It is a snowmobile that characterized the door.

The upper end of the air cleaner connected to the vaporizer is preferably disposed at substantially the same height as the upper end of the vaporizer in a side view .
Further, it is preferable that an exhaust manifold is extended forward from the 4-cycle engine and a supercharger is installed.
Moreover, it is preferable to provide an opening for communicating the inside and outside of the engine room at a position facing the bottom of the engine oil pan at the bottom of the engine room, and a lid member that allows the opening to be opened and closed.

  According to the snowmobile of the present invention, the oil supply system in the engine is a dry sump type, so that the engine body can be configured low, and by providing an oil tank separate from the engine in the engine room, 4 The mounting of the cycle engine can be realized, and an excellent effect can be achieved that the space in the engine room can be saved by effectively using the space in the engine room.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partial cross-sectional side view showing the overall configuration of a snowmobile according to an embodiment of the present invention.

As shown in FIG. 1, the structure of the four-cycle engine for a snowmobile according to the embodiment is formed inside the front cover 4 on the front side of the vehicle body in the snowmobile 1, with the four-cycle engine 2 having the cylinder head 3 disposed on the upper side. A crankshaft (not shown) is disposed in the engine room 6 so as to be substantially parallel to the vehicle body width direction, and the engine 2 main body is inclined forward toward the vehicle body traveling direction. An intake path 5 is arranged.
The engine 2 has a dry sump type as a refueling system in the engine.

Here, the structure of the snowmobile 1 will be described in detail.
As shown in FIGS. 1 and 2, the snowmobile 1 is rotatably installed at a lower part of a frame front portion 11 of a vehicle body frame 10 extending in the front-rear direction so that a pair of left and right steering sleds 13 face in the left-right direction. A driving crawler 16 that circulates the track belt 15 is disposed below the frame rear portion 12. The crawler 16 circulates by being wound around a drive wheel 17 disposed at the front end of the frame rear portion 12, a driven wheel 18 disposed at the rear end, a plurality of intermediate wheels 19, a suspension mechanism 20, and each wheel. A track belt 15 is provided.

  The vehicle body frame 10 is formed in a monocoque frame structure, and a front portion of the frame (engine mount frame) 11 on which the engine 2 is mounted is formed so that a front portion protrudes upward from the main portion 11a. A front suspension housing 11b that accommodates the upper portion of the supporting front suspension 13a is formed, and a track housing 11c that accommodates the vicinity of the upper portion of the crawler 16 near the driving wheel 17 with a rear portion rising obliquely upward and rearward from the main portion 11a. Is formed continuously and integrally with the frame rear portion 12.

The frame rear portion 12 extends over the rear end portion in the vehicle front-rear direction that also serves as a cover that accommodates the entire crawler 16 downward.
Further, a bowl-shaped seat 22 is disposed above the rear portion 12 of the frame, and steps 23 that are one step lower than the seat 22 are provided on both sides of the seat 22 in the vehicle width direction.
A steering shaft 24 is erected substantially at the center of the vehicle body between the seat 22 and the front cover 4, and a bar handle 26 is inclined at the upper end of the steering shaft 24 and extends in the horizontal direction from side to side. ing.

In front of the bar handle 26, a windshield 28 is erected, and the front cover 4 is substantially streamlined from the base of the windshield 28 and gently lowered toward the front. Presents.
The steering sled 13 is operated via the steering shaft 24 by the bar handle 26.

Next, the configuration of the engine 2 will be described in detail.
As shown in FIG. 1, the engine 2 is a four-cycle engine, and its crankshaft (not shown) is substantially parallel to the vehicle body width direction, and the cylinder head 3 side is greatly inclined toward the vehicle body traveling direction. In this way, the engine room 6 inside the front cover 4 is disposed substantially in the center.
An intake path 5 such as a carburetor or a throttle body is provided on the upper side of the engine 2 main body, and an alternator 31 is disposed behind the intake path 5 and an air cleaner 32 is disposed further rearward.

A V-belt type continuously variable transmission (not shown) is provided with a flywheel (not shown) at one end of the crankshaft (left side facing the vehicle body traveling direction) and a centrifugal clutch device built in the outside of the flywheel. It is connected. The continuously variable transmission is configured to transmit drive to the track belt 15 via a passive gear or the like. A brake (not shown) is provided at the other end of the passive shaft of the continuously variable transmission.
At the other end of the crankshaft (on the right side in the vehicle traveling direction), a pulley 34 is provided as auxiliary device driving transmission means so as to drive the alternator 31 and the water pump 35 provided on the pulley 34 side. Has been.

  A starter motor (not shown) is disposed below the intake path 5 such as a carburetor or a throttle body in the vicinity of the flywheel on the upper side of the engine 2 body. An intake manifold 37 is arranged on the upper side of the main body of the engine 2 so that the intake passage 5 from the carburetor 36 is branched into and communicated with the intake holes of the respective cylinders. An intake system from the intake manifold 37 to the carburetor 36 and the air cleaner 32 is arranged so as to extend rearward at a position higher than the upper position of the cylinder head 3.

The intake system is located inside the windshield 28 near the base of the front cover 4 that is raised. Further, the upper end portion of the cylinder head 3 is accommodated without interfering with other components inside the front cover 4 which is gently lowered.
In the exhaust system, a supercharger 7 is installed by extending an exhaust manifold (not shown) from the cylinder case 39 to the front of the engine 2, and from the front of the engine 2 body along the engine 2 body from the supercharger 7. An exhaust passage is formed toward the rear, and communicates with a muffler (not shown) installed on the rear side of the engine via the exhaust passage.

  As shown in FIG. 1, in the engine room 6, the engine 2 has an oil pan 38 adjacent to an inclined track housing 11c in a state where the engine 2 is inclined forward on the frame front portion 11, and The engine 2 is mounted along the frame front portion 11 with the cylinder case 39 adjacent to the front suspension housing 11b.

In front of the engine 2, an oil tank 40 is disposed separately from the engine 2 on the upper surface of the front suspension housing 11b.
The engine oil supplied to each part of the engine returns to the oil pan 38, is sent to the oil tank 40 via the oil strainer 41, and is appropriately supplied again to each part of the engine from there.

The main portion 11a, which is a part of the engine room bottom 6a, includes a maintenance opening 50 that communicates the inside and outside of the engine room 6 at a position facing the bottom of the oil pan 38 of the engine 2, and the opening. A lid 51 is provided so that 50 can be freely opened and closed.
The opening 50 has a substantially rectangular shape, and is formed to have a size that allows maintenance of the oil pan 38 from the lower side of the engine room 6.
One end of the lid 51 is engaged with one end of the opening 50 by a connecting means 52 such as a hinge so as to be freely swingable. On the other hand, a lock mechanism 53 is provided at the other end of the lid 51 so that the lid 51 is securely fixed to the engine room bottom 6a when the opening 50 is closed.

Since it is configured as described above, according to the present embodiment, the engine 2 is a dry sump engine, the engine 2 is tilted forward, and the oil pan 38 at the bottom of the engine 2 is disposed close to the main portion 11a. The engine 2 could be arranged in the engine room 6 in a compact manner.
In addition, since the oil tank 40 is installed on the upper surface of the front suspension housing 11b that projects from the engine head 6 in front of the cylinder head 3 of the engine 2, a space-saving engine structure that uses the space in front of the engine 2 can be obtained. The engine oil can be efficiently cooled by the driving wind without being affected by the heat from the engine.

In addition, since the maintenance opening 50 is formed at the position facing the oil pan 38 in the engine room bottom 6a, maintenance work such as oil change can be performed from the outside of the engine room 6 and the maintenance performance is greatly improved. We were able to.
Further, since the opening 50 can be freely opened and closed, there is an advantage that the running performance of the snowmobile is not affected.

  In the present embodiment, the engine 2 is tilted forward and mounted in the engine room 6. However, the present invention is not limited to this, and for example, a modification 1 is shown in FIG. As described above, the engine 102 may be mounted substantially vertically in the engine room 6 and the oil tank 141 on the upper surface of the front suspension housing 11b in front of the engine 102 may be installed. This is easy from the present invention. It can be expanded to.

  In the present embodiment, the oil tank 40 is disposed on the upper surface of the front suspension housing 11b in front of the engine 2. However, the present invention is not limited to this, for example, a two-dot chain line in FIGS. As shown, the oil tank 140 may be disposed on the upper surface of the track housing 11 c behind the engine 2. In this case, the space on the upper surface of the track housing 11c behind the engine 2 can be effectively used to save space, away from the heat generating part of the engine, and also to have a cooling effect due to snow dust wound up during traveling. The engine oil can be cooled efficiently.

Further, in the present embodiment, the opening 50 formed in the engine room bottom 6a is opened and closed by a swingable cover 51. However, the present invention is not limited to this, and for example, deformation As an example 2, as shown in FIGS. 3 and 4, a cover 151 having substantially the same shape as the opening 150 formed in the engine room bottom 6 a is provided separately, and the cover 151 is fitted into the opening 150. Then, it may be fixed integrally with the engine room bottom 6a by a fastening member 152 such as a fastening bolt. Reference numeral 153 in the figure is a screw hole into which the fastening member 152 is fastened.
In this case, by making the opening 150 convex to the inside of the engine room 6 approximately the same as the height of the cover 151, the cover 151 can be configured on the substantially same plane as the engine room bottom 6a. It has the effect of improving appearance and reducing running resistance.

  Further, as a third modification, as shown in FIGS. 5 and 6, an opening 250 having a screw part 250 a formed on the inner periphery is formed in the engine room bottom 6 a so as to protrude into the engine room 6 and the screw part is formed on the outer periphery. The lid portion 251 in which the screw portion 251a corresponding to 250a is formed may be provided separately. In this case, when attaching the lid 251 to the opening 250, no other attachment member is required, so that the workability can be improved and the number of parts can be reduced, so that the cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional side view showing an overall configuration of a snowmobile that employs a snowmobile four-cycle engine according to an embodiment of a snowmobile of the present invention. It is a fragmentary sectional top view which shows the whole structure of the snowmobile of the modification 1 of this embodiment. It is a section side view showing composition of an engine room bottom part of modification 2 of this embodiment. It is a lower side top view which shows the structure of the said engine room bottom part. It is a section side view showing the composition of the engine room bottom part of modification 3 of this embodiment. It is a lower side top view which shows the structure of the said engine room bottom part. It is a fragmentary sectional side view which shows the whole structure of the snowmobile carrying the conventional 4-cycle engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Snowmobile 2, 102 Engine 4 Front cover 6 Engine room 6a Engine room bottom part 7 Supercharger 10 Body frame 11 Frame front part (body frame front part)
11a Main part 11b Front suspension housing 11c Track housing 13 Steering sled 16 Crawler 17 Drive wheel 24 Steering shaft 26 Bar handle 28 Wind shield 36 Vaporizer 37 Intake manifold 38, 138 Oil pan 40, 140, 141 Oil tank 41 Oil strainer 50 , 150, 250 Opening 51, 151, 251 Lid

Claims (4)

A four-cycle engine is installed in the engine room, which is equipped with a crawler and covered with a front cover on the front side of the vehicle body. The front part of the vehicle body frame protrudes upward from the bottom of the engine room and houses the front suspension upper part. A suspension housing and a track housing that accommodates the crawler drive wheels in a shape that the rear portion rises upward from the bottom of the engine room , a windshield is formed on the front cover near the bar handle, and the steering shaft is formed by the bar handle In a snowmobile equipped with a 4-cycle engine that operates the steering sled via
The oil supply system of the four-cycle engine is a dry sump type that includes an oil tank separate from the four-cycle engine disposed in the engine room, and sends engine oil to the oil tank via an oil strainer in an oil pan. ,
While disposing the oil pan close to the bottom of the engine room between the front suspension housing and the track housing,
The front cover has a shape that gently falls from the windshield base toward the front of the vehicle body as a substantially streamline shape,
The carburetor constituting the intake path is disposed at a position higher than the upper position of the cylinder head of the 4-cycle engine and inside the windshield base front end portion of the front cover in a side view, and the oil strainer is vaporized. A snowmobile characterized by being placed vertically below the vessel . The snowmobile according to claim 1, wherein an upper end portion of an air cleaner connected to the vaporizer is disposed at substantially the same height as the upper end portion of the vaporizer in a side view .   The snowmobile according to claim 1, wherein an exhaust manifold is extended forward from the four-cycle engine, and a supercharger is installed.   The engine room bottom is provided with an opening communicating the inside and outside of the engine room at a position facing the bottom of the oil pan of the engine, and a lid member that allows the opening to be opened and closed. The snowmobile according to any one of 1 to 3.

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