JP2004211710A - Small snowmobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small snowmobile with a low-profile four-cycle engine mounted in a front cover thereof, allowing the steering of front parts of right and left sleds without any trouble, achieving clean emission and reducing noises and vibration. <P>SOLUTION: The small snowmobile comprises the right and left sleds 19 to be steered via a steering shaft 20 by a crew steering bar handle 18, an oil pan 16 provided in the frontward tilted front cover 13, and the four-cycle engine 1 mounted to be started by a starter motor 24. The four-cycle engine 1 is inclined and an intake passage between a carburetor 11 connected to an intake pipe 9 connected to a cylinder head 8 of the four-cycle engine 1 and an air cleaner 12 extends backward almost straight and is arranged on a rear inside 13a of the front cover 13, while a recessed portion 17 directed upward is provided on an oil pan 16. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a small snowmobile on which a four-cycle engine is mounted.

  Riding over the seat attached to the upper surface of the rear part of the frame, the track belt at the lower part of the rear part of the frame is driven by an engine mounted on the front part through a continuously variable transmission, and the front left and right sleds are steered by bar handles. There is a small snowmobile called a running snowmobile.

In this type of snowmobile, a power source is generally a two-stroke engine and drives a track belt (for example, see Patent Documents 1 and 2).
The two-stroke engine has a large output while being lightweight and compact, and is convenient to be mounted in a front cover of a small snowmobile at the front down (see Patent Documents 1 and 3).
JP-A-7-125679 JP-A-9-195762 JP-A-7-228288

  However, compared to a four-cycle engine, a two-stroke engine is inferior in cleanliness because it has larger noise and vibration, a larger amount of exhaust gas, and the exhaust gas contains lubricating oil after use.

On the other hand, a four-cycle engine has less noise and vibration, a smaller amount of exhaust gas, and a better cleanness than a two-cycle engine. However, a four-stroke engine requires a large cylinder head with an intake / exhaust valve mounted on the cylinder, and an oil pan containing lubricating oil is installed on the lower side of the crankcase.
For this reason, there is a problem that the overall height is large and the weight is heavy, which is disadvantageous for weight reduction, and it is difficult to mount the small snowmobile in the front cover of the downhill front.
If the engine is tilted forward as a countermeasure, there arises a problem that the oil pan interferes with the steering shaft, so that the engine cannot be arranged just below the bottom in the engine room.

  The present invention has been made in view of the above problems, and even if a four-stroke engine is mounted with a reduced height in the front cover of a small snowmobile, steering of the front left and right sleds is not hindered. The objective is to obtain a small snowmobile that is clean and has low noise and vibration.

In order to achieve the above object, the present invention has the following configuration.
The present invention is directed to a small snowmobile equipped with a four-cycle engine that steers left and right sleds via a steering shaft with an occupant's steering bar handle via a steering shaft, includes an oil pan in a front cover having a forward-downward shape, and is started by a starter motor. In a car, the four-cycle engine is tilted, and the intake path of a carburetor and an air cleaner connected to an intake pipe connected to a cylinder head of the four-cycle engine is extended almost straight rearward so as to be inside the rear part of the front cover. A small snowmobile in which an oil pan is provided with a concave portion facing upward while being arranged.
In the present invention, it is preferable that a deep portion is formed in the oil pan, and an oil strainer of an oil pump device is disposed in the deep portion.

In the present invention, by inclining the four-cycle engine, the vertical dimension of the engine itself can be reduced, and the overall height can be reduced.
Then, interference can be avoided by the recess provided in the oil pan at the lower end of the engine, and the mounting position of the engine can be lowered accordingly. In this way, the four-stroke engine can be accommodated in the front cover that is lowered downward.
Also, the carburetor and the air cleaner of the engine can be installed inside the higher position at the rear of the front cover.
In this way, a four-stroke engine can be mounted on the front of a small snowmobile, and a small snowmobile with clean exhaust gas, low noise and vibration, and a comfortable ride can be obtained. .

  In addition, the oil strainer of the oil pump device that sucks the lubricating oil is located in the deep part of the oil pan, so that it becomes a part where the oil accumulates securely and does not suck air. Can be performed without any trouble, and insufficient lubrication does not occur.

Hereinafter, an embodiment of a small snowmobile according to the present invention will be described with reference to FIGS.
As shown in FIGS. 1 to 6, the engine 1 of the small snowmobile according to the embodiment is a four-cycle multi-cylinder engine in which a crankshaft 2 (also in a cylinder arrangement direction) is oriented in a vehicle traveling direction. This is a horizontal engine that is oriented in the left-right direction with respect to the engine.

  The drive side 5a of the continuously variable transmission 5 with the V-belt 4 is connected to one end (the left end in the embodiment) of the engine crankshaft 2. The passive side 5b of the continuously variable transmission 5 is connected to the track belt 6 via a gear or the like so that the track belt 6 can be driven.

  In the engine 1, the cylinder 7 is largely inclined forward (inclined by 45 ° or more in the embodiment), and the cylinder head 8 is mounted on the upper side.

  The cylinder head 8 has an intake pipe 9 connected to the rear side and an exhaust pipe 10 connected to the front side. The intake path of the carburetor 11 and the air cleaner 12 connected to the intake pipe 9 is arranged to extend almost straight rearward, and the carburetor 11 and the air cleaner 12 can be arranged on the inner side 13a which is located at a high position at the rear of the front cover 13. .

  The exhaust pipe 10 is connected to the exhaust manifold 10 a of the engine 1 at a location where the exhaust pipe 10 is gathered and united, extends toward the other end of the crankshaft 2 (to the right in the embodiment), and then extends to the inner wall of the front cover 13. At the approaching position, it bends rearward in an L-shape, and is connected to the muffler 14 disposed near the other side of the crankcase 15 of the engine 1 (the right side in the embodiment).

  Thus, an oil pan 16 is connected to the lower side of the crankcase 15 of the engine 1 to store the lubricating oil in the engine.

  The oil pan 16 is provided with an inverted U-shaped gouge 17 that is recessed toward the cylinder head 8 at the center of the lower surface in a direction orthogonal to the crankshaft 2.

  Then, a steering shaft 20 that steers the front left and right sleds 19 in the left and right directions with the occupant's steering bar handle 18 is passed through the hollow 17.

  By disposing the steering shaft 20 so as to be accommodated in the recess 17, the steering shaft 20 can be wrapped with the oil pan 16, and the mounting position of the engine 1 can be lowered and rearward by that much.

For this reason, the engine 1 can lower the height of the engine 1 and the mounting position of the engine 1 by tilting the cylinder 7 forward and wrapping the steering shaft 20 and the oil pan 16.
As a result, the engine 1 can be housed in the front cover 13 descending to the front frame 3.

Here, as shown in FIG. 3, the oil pan 16 is provided with a lubricating oil pump device (shown in the drawing) in which the depth of both sides 16a and 16b of the lower surface provided with the inverted U-shaped gouge 17 is changed. The oil strainer 21 (omitted) is arranged.
Since the lubricating oil is sucked from the oil strainer 21 in the deep part, there is no fear of insufficient lubrication.

  A drive side 5a of the belt-type continuously variable transmission 5 is provided with a centrifugal clutch device 22, and a drive side 5a is provided on a gear 23 on the outer periphery of a pulley. The pinion 24a of the starter motor 24 can be cranked at the start of the engagement. An alternator 25 driven by a belt is provided at the other end of the crankshaft 2 so as to generate power.

With the configuration described above, the vertical dimension of the engine 1 itself can be shortened by tilting the cylinder 7 of the four-cycle engine 1 forward.
The oil pan 16 and the steering shaft 20 can be wrapped by passing the steering shaft 20 through a gouge (recess) 17 provided in the oil pan 16 at the lower end of the engine 1. Can be lowered by that amount.
In this manner, the four-cycle engine 1 can be accommodated in the front cover 13 that is lowered forward.

Further, since the oil strainer 21 for sucking the lubricating oil is arranged at a deep portion on the deep side of the oil pan 16, it becomes a portion where the oil is reliably stored, and there is no lack of lubrication because no air is sucked.
In addition, the carburetor 11 and the air cleaner 12 of the engine 1 can be installed inside a higher position at the rear of the front cover 13.

  In this manner, the four-stroke engine 1 can be mounted on the front of the small snowmobile, so that the small snowmobile has a clean exhaust gas, low noise and vibration, and a comfortable ride. it can.

It is a side view in the state where the engine of the small snowmobile concerning the embodiment of the present invention was mounted. It is a top view in the state where the engine of the small snowmobile was mounted. FIG. 3 is a rear view of the engine alone. FIG. 2 is a partial vertical cross-sectional view of the engine according to the embodiment of the present invention, as viewed from a direction indicated by an arrow A in FIG. 1. FIG. 2 is an overall side view of the small snowmobile. FIG. 2 is an overall plan view of the small snowmobile.

Explanation of reference numerals

1 engine (four-cycle engine)
2 Crankshaft 3 Frame 7 Cylinder 8 Cylinder head 9 Intake pipe 11 Vaporizer 12 Air cleaner 13 Front cover 15 Crankcase 16 Oil pan 17 Gouge (dent)
18 Steering bar handle 19 Sledding 20 Steering shaft 21 Oil strainer

Claims (2)

A small snowmobile equipped with a four-stroke engine that steers the left and right sleds via the steering shaft with the occupant's steering bar handle via the steering shaft, has an oil pan in the front cover of the downwardly falling shape, and starts with a starter motor,
The four-stroke engine is tilted, and the intake path of the carburetor and the air cleaner connected to the intake pipe connected to the cylinder head of the four-stroke engine is extended almost straight rearward and is arranged inside the rear of the front cover. A small snowmobile, wherein an upward recess is provided in the oil pan. The small snowmobile according to claim 1, wherein a deep portion is formed in the oil pan, and an oil strainer of an oil pump device is disposed in the deep portion.

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