JPH01289790A - Snow vehicle - Google Patents

Abstract

PURPOSE:To enable a spatial margin to be formed on the sides of an engine by forwardly inclining, in the fore-and-aft direction, the front cylinder of the multiple cylinder engine in a snow vehicle so called a snowmobile, while erecting the rear cylinder in the vertical direction, and by overlapping the front and rear cylinders in the vehicle width direction. CONSTITUTION:A snow vehicle is provided with a traveling track 41 consisting of an endless body at the lower part of the rear half vehicle body, and this is driven by the power of an engine 1. And a pair of steering skis are provided on the right and left sides of the front lower part of the vehicle body so as to be steerable by a steering wheel. In this case, the front cylinder 2a to the two-cylinder two-cycle engine 1 having been laterally laid on the vehicle body on the far side to the sheave 6 which has been fixed to the end part of a crankshaft 5 (not shown) is arranged in such a position as to be inclined nearly in the horizontal direction, while the rear cylinder 2b on the near side to the sheave 6 is arranged in such a position as to be tilted slightly forward to the vertical direction. Further, respective cylinders 2a, 2b are offset in their axes by a little distance in the width direction, and are arranged so as to be overlapped each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a snowmobile equipped with a multi-cylinder engine.

[Prior art]

Conventionally, when installing a multi-cylinder engine in a snowmobile,
Generally, a parallel multi-cylinder type is used, and it is placed horizontally with the crankshaft in the width direction, and the power is transmitted from the sheave installed at the end of the crankshaft to the drive wheels of the truck via a belt, chain, etc. I was trying to do that. but,
When a parallel multi-cylinder engine is installed in this way, the long crankshaft means that the engine occupies most of the width of the car body, making it extremely difficult to lay out other parts within the limited space. There was a problem.

Furthermore, as the number of cylinders increases, the weight of the engine also increases, but since all of these cylinders are arranged in an upright position, the center of gravity relative to the vehicle body also has to be higher.

[Purpose of the invention]

An object of the present invention is to provide a snowmobile in which, when a multi-cylinder engine is mounted horizontally, the width of the engine in the direction of the crankshaft can be shortened, other parts can be laid out on the side of the engine, and the center of gravity can be lowered. It's about doing.

[Structure of the invention]

To achieve the above object, the present invention provides a track at the rear of the vehicle body, and an engine room surrounded by left and right steering skis and a shroud at the front of the vehicle body, and a multi-cylinder engine is installed horizontally in the engine room. In a snowmobile equipped with a stand-alone vehicle,
The multi-cylinder engine is characterized in that the front cylinders of the multi-cylinder engine are tilted forward in the longitudinal direction, and the rear cylinders are vertically arranged, and the front cylinders and the rear cylinders overlap each other in the width direction of the vehicle body. It is something.

The present invention will be explained below with reference to embodiments shown in the figures.

FIG. 4 shows an example of a snowmobile according to the present invention. A running track 41 consisting of an endless strip is provided at the lower part of the rear half of the vehicle body, and is driven by a drive wheel 42 provided at the front end of the track 41 for running. Power is input to the drive wheels 42 from an engine, which will be described later, and the engine is provided in an engine room surrounded by a shroud 43 that covers the front of the vehicle body. Further, steering skis 44, 44 are provided on the left and right sides of the lower part of the front part of the vehicle body, and are adapted to be steered by a handle 45 on the driver's seat. 46 is a sheet.

1 and 2 show the inside of the front part of the vehicle body of the snowmobile. There are two frames 47 on the left and right sides of the car body.
．． 47 are provided in parallel, and the front end thereof is connected to a cross member 48.
are connected.

Reference numeral 49 denotes a steering shaft, the above-mentioned handle 45 is provided at the upper end, and left and right steering skis 44, 44 are connected to the lower end so as to be interlocked.

1 is an engine placed horizontally on the car body, and its crankshaft 5
is in the width direction of the vehicle. A sheave 6 is fixed to the end of the crank 5 so as not to interfere with the frame 47, and power is transmitted to the drive wheels 42 of the truck 41 through the V-belt 7 wound around the sheave 6. It has become.

In this embodiment, the engine 1 is a two-stroke engine, and consists of two cylinders, a front cylinder 2a and an intake M2b, and both cylinders are L-shaped when viewed from the side. That is, the front cylinder 2a located on the far side with respect to the sheave 6 is tilted forward and extends in the front-rear direction, and is in a position slightly upward from horizontal, and the rear cylinder 2b is located on the side close to the sheave 6. It stands vertically and is tilted slightly forward from the vertical direction. By holding both cylinders in this position, the included angle is 90.
It is L-shaped with a slightly smaller angle.

Furthermore, both cylinders 2a and 2b are in such a relationship that their axes are offset by a slight distance e in the width direction, and their bodies overlap each other. Due to this opening, the crankshaft is shortened compared to a conventional parallel two-cylinder engine, and the length of the engine 1 in the width direction of the vehicle body is significantly shortened.

The engine 1, which has been shortened in the width direction of the car body in this way, can be mounted so as to be offset to the left side in the direction of travel, as shown in Figure 1, and the other parts can be laid out on the right side for comparison. It can create a large space. In order to mount engine 1 in such an unevenly distributed position,
A mount boss 3 is provided at the front end of the lower part of the engine so as to pass through from side to side, and a vibration isolating rubber 55 is attached to the mount boss 3.
The support bolt 4 is inserted through the (see Figure 3)
. One end of the support bolt 4 is fixed to a bracket 50 on the left frame 47, and the other end is fixed to a bracket 51 welded to the center of the cross member 48. On the other hand, at the rear of the engine, a fixing bracket 52 is provided only at one location on the left end, and is fixed to a bracket 53 on the vehicle body frame side via a vibration isolating rubber 54.

A starter motor 14 is provided at the lower rear end of the engine l mounted in this manner. Further, an intake silencer 8 is provided in the rear upper region of the engine 1. Intake passages 9, 9 extend downward from the intake silencer 8 in a nearly vertical manner and are connected to the crankcase of the engine 1.

Furthermore, exhaust pipes 10a and 10b are attached to the sides of the L-shaped cylinders 2a and 2b facing each other, respectively, and these extend forward and are connected to a muffler 11 disposed on the side of the engine. It looks like this. on the other hand,
For the exhaust pipes 10a and 10b arranged in this way,
An air hole 56 for introduction is provided at the front end of the shroud 43, and an air hole 5 for extraction is provided at a position behind the engine 1.
7 is provided. This allows the running wind introduced from the air hole 56 at the front end to the cylinders 2a, 2b, the exhaust pipe 10a,
After cooling 10b, it is discharged outside from the air hole 57 at the rear. In this way, the exhaust pipe, which is the heat source, is concentrated in the valley between both cylinders, and the valley is directed forward.
Traveling wind from the air hole 56 can easily enter, allowing efficient cooling.

Further, both cylinders 2a and 2b are surrounded by a hood, and a cooling fan 12 is installed in an L-shaped space sandwiched between these two cylinders, and this cooling fan 12 is further installed in a shroud 43 via a hood 13. It is connected to the opening 58 (FIG. 5). Therefore, by rotating this cooling fan 12, outside air is actively introduced into the L-shaped space, thereby further improving the cooling effect of both cylinders 2a and 2b.

Figures 5.6.7 show the above-mentioned L-type two-cylinder engine in more detail.

Both cylinders 2a and 2b have pistons 15a and 15b, respectively.
are inserted, and the small ends of connecting rods 16a, 16b are connected to these pistons 15a, 15b, respectively.

Further, one crankcase 18 common to the two cylinders 2a and 2b is provided, and this crankcase 1
One crank pin 1 is attached to the crankshaft 5 installed in the crankshaft 8.
7 should pass through it.

At the center of this crank pin 17 is a disk-shaped partition plate 17.
d is integrally formed in an eccentric manner, and this partition plate 17d separates the crankcase 18 into two crank chambers 18a,
18b, and these crank chambers 18a, 18
Both cylinders 2a and 2b correspond to cylinders b, respectively. The disk-shaped partition plate 17d that partitions the two crank chambers 18a and 18b allows the crankshaft 5 to be inserted while maintaining the partitioned state.
It is designed to rotate together with the

The large ends of the connecting rods 16a, 16b extending from the cylinders 2a, 2b are respectively connected to the single crank pin 17 by sandwiching a slightly thick partition plate 17d. That is, by connecting the two connecting rods 16a and 16b to the single crank pin 17 at the same time, the length of the crankshaft 5 is significantly shortened.

Two crank chambers 18a, 18 in the crankcase 18
Two carburetors 20a and 20 are installed at the rear upper part of b.
b is connected to left and right integrated reed valve units 21a and 21b, and this connection forms an intake passage 9.9 that is linear and nearly vertical. By forming the intake passage 9 in a straight line in this manner, intake resistance is reduced. As shown in FIG. 8-9, the left and right reed valve units 21a and 21b are partitioned at the center by a partition plate 22 to form a pair of left and right passages 23a and 23b each having a triangular cross section. These are connected to the crank chambers 18a, 18b by being provided with reed valves 24a, 24b, respectively.

As described above, in the above-mentioned two-cylinder engine installed in the snowmobile of the present invention, the front cylinder 2a is tilted forward in the longitudinal direction, the rear cylinder 2b is vertically arranged, and both cylinders are placed over each other. Since it is overlapped and offset in the width direction of the vehicle body, the crankshaft is shortened compared to a conventional parallel two-cylinder engine. therefore,
By shortening the crankshaft, the length that the engine 1 occupies in the vehicle body width is shortened, and it becomes possible to create sufficient space on the side of the engine to lay out other parts.

This shortening of the rank shaft 5 can be further facilitated by using one crank pin 17 for two cylinders as in the above-described embodiment. Furthermore, as in the above-mentioned embodiment, if the cylinder 2b of the two cylinders that is closer to the sheave 6 is installed upright in the vertical direction, it is possible to get closer to the sheave 6 without interfering with the frame 47. Therefore, it becomes possible to further simplify the shortening.

In addition, since the engine 1 has the front cylinder 2a tilted forward in the longitudinal direction, the shroud 43 at the front of the vehicle body can be made into a slant nose with the lowest possible slope by tilting the front cylinder 2a forward. Resistance can be further reduced. Additionally, by tilting the cylinders forward, the overall center of gravity of the engine can be lowered, further improving vehicle stability. This lowering of the center of gravity can be made even more advantageous by arranging the heavy starter motor 14 below the engine as in the above embodiment.

On the other hand, by erecting the rear cylinder 2b in the vertical direction,
There is more space at the rear of the engine, the capacity of the intake silencer 8 placed here can be increased, and the heavy crankcase can be moved to the rear.
Allows the center of gravity to move backwards. Therefore, quietness and stability during operation can be achieved by these.

In addition, as in the example, the valley between the L-shaped cylinders is directed forward, and the exhaust pipes from both cylinders are led out into the valley, making exhaust treatment easier and cooling efficiency due to the running wind. can be improved.

In addition, although the above-mentioned embodiment was explained in the case of a two-cylinder engine, the present invention can be similarly applied to an engine with three or more cylinders.

[Effects of the Invention] As described above, the present invention provides a snowmobile in which a multi-cylinder engine is mounted horizontally on the vehicle body, in which the front cylinders of the multi-cylinder engine are tilted forward in the longitudinal direction, and the rear cylinders are vertically erected. In addition, these front and rear cylinders are arranged to overlap with each other in the width direction of the vehicle body, so that the width of the engine in the direction of the crankshaft can be shortened and a space for laying out other parts on the side of the engine can be easily created. You will be able to do this. In addition, the center of gravity is lowered and vehicle stability can be improved.

Additionally, since the front cylinders are tilted forward in the longitudinal direction, it is possible to create a slant nose at the front of the vehicle body, reducing air resistance. On the other hand, since the rear cylinder was installed vertically,
The extra space at the rear of the engine allows the capacity of the intake silencer to be increased, which also allows the center of gravity to be moved rearward. Therefore, it is possible to improve the quietness during driving and the stability of the vehicle body.

Furthermore, the exhaust pipes from both cylinders can be gathered between the front cylinder and the rear cylinder, making exhaust treatment easier and improving the cooling effect.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the inside of the front part of a snowmobile according to an embodiment of the present invention, FIG. 2 is a side view of the same, FIG. 3 is a schematic view showing the support structure for the mounted engine, and FIG. 4 5 shows a side view of the snowmobile as a whole, FIG. 5 is a vertical cross-sectional view of the engine taken along the crankshaft direction, and FIG. 6 shows a cross-section of the engine at right angles to the crankshaft at the rear cylinder. Figure 7 is a longitudinal cross-sectional view of the same engine, taken in a section perpendicular to the crankshaft at the front cylinder, and Figure 8 is a longitudinal cross-sectional view of the main parts of the same engine, showing the intake passage in cross-section. 9 is a view taken along arrow IX-■ in FIG. 8, showing only the intake valve portion. DESCRIPTION OF SYMBOLS 1... Engine, 2a... Front cylinder, 2b... Rear cylinder, 5... Crankshaft, 6... Sheave, 7... Belt, loa, IOB... Exhaust pipe, 11. 7 Fuller,
47...Frame. Agent Patent Attorney Nobuo Ogawa −

Claims (1)

[Claims] A snowmobile in which a track is provided at the rear of the vehicle body, and an engine room surrounded by left and right steering skis and a shroud is provided at the front of the vehicle body, and a multi-cylinder engine is mounted horizontally in the engine room. A snowmobile in which the front cylinder of the vehicle is tilted forward in the longitudinal direction, the rear cylinder is vertically arranged, and the front cylinder and the rear cylinder overlap each other in the width direction of the vehicle body.