JPS621864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small snowmobile having a track that is movable up and down.

In small snowmobiles having tracks (endless track belts), the tracks are elastically held vertically in order to improve running stability, particularly at high speeds, and to provide good riding comfort. A drive sprocket that is pivotally supported on the frame, a slide rail that is held below the frame so that it can move up and down and that extends in the front and back direction, a guide wheel that is rotatably supported on the rear end of this slide rail, and In a small snowmobile equipped with a drive sprocket, a slide rail, and a track wrapped around a guide wheel, a link mechanism and guide wheel that hold the slide rail within the space surrounded by the track, as well as a buffer spring and a damping device are generally required. A suspension mechanism such as the following is installed. However, in this case, the mechanism within the space surrounded by the track becomes complicated, and the problem arises that the range of vertical movement of the track cannot be sufficiently increased. There is also the problem that snow and ice tend to stick to the links, buffer springs, etc. in the truck, especially when driving on wet snow.

Therefore, there is a mechanism in which a part of the link mechanism protrudes on both the left and right sides of the truck, and a shock absorber is installed vertically or diagonally between this protruding end and the frame, but in this case, the range of vertical movement of the truck is increased. In order to do this, the shock absorber had to be made longer, which caused the problem that the shock absorber protruded upwards from the frame. Further, in this case, since a vertical force is applied to the frame supporting the upper end of the shock absorber, there is also the disadvantage that the vertical rigidity of the frame must be increased and the frame must be reinforced.

This invention was made in view of the above circumstances, and it simplifies the mechanism such as links housed in the space inside the truck, sufficiently widens the range of vertical movement of the truck, and prevents snow and ice from falling inside the truck. To provide a small snowmobile that is difficult to stick to the space of the vehicle and also eliminates the need to increase the rigidity of the frame in the vertical direction too much.

According to the present invention, this purpose consists of a drive sprocket pivotally supported by a frame, a slide rail extending in the front and back direction that is held below the frame so as to be movable up and down, and a rear end of the slide rail that is rotatable. In a small snowmobile equipped with a guide wheel that is pivotally supported by the snowmobile, and a track that is wound around the drive sprocket, the slide rail, and the guide wheel, the snowmobile has a cylindrical shape extending in the front-rear direction almost along the seat mounting surface of the frame. This is achieved by a small snowmobile characterized in that a shock absorber is provided, and the slide rail is connected to the shock absorber via a link mechanism so that vertical movement of the slide rail causes the shock absorber to expand and contract. The present invention will be explained in detail below based on the drawings.

1 to 6 show a first embodiment of the present invention, FIG. 1 is a side view, FIG. 2 is a vertical sectional side view of the main part, FIG. 3 is a cross-sectional view taken along the - line, and FIG. FIG. 5 is a sectional view taken along the - line, and FIG. 6 is a side view showing the truck at its upper limit position. In these figures, reference numeral 1 denotes an aluminum frame, which is bent so that its cross section is convex upwards as shown in Figure 3, and the interior thereof becomes a truck housing 2 that opens rearward, and also opens left and right. The approximately horizontally protruding portion is a step 3. A pair of left and right shock absorber holding tubes 4 are fixed to the front part of the frame 1, and skis 6 are fixed to the lower end of a cylindrical shock absorber 5 rotatably held within the shock absorber holding tubes 4. ing. The skis 6 are supported by the shock absorber 5 so as to be movable up and down. An arm 7a is rotatably held in the shock absorber holding cylinder 4, and the rotation of the handlebar 7 is controlled by this arm 7.
a and the link mechanism to the ski 6, and the ski 6 and shock absorber 5 rotate as one. 8 is a synthetic resin cowling that covers the lower part of the front part of the frame 1, and 10 is a windshield.

A seat 11 is fixed to the upper surface of the frame 1, that is, the seat mounting surface. sheet 11
is a back plate 12 made of plywood that is in contact with the top surface of the frame 1;
The sponge 13 on the back plate 12 and this sponge 13
It consists of an outer skin 14 that covers the. Note that an opening 15 that is long in the front-rear direction is formed approximately in the center of the back plate 12, a cover 16 is fixed to this opening 15 so as to fit inside the sponge 13, and a shock absorber loading chamber 17 is formed within this cover 16. (See Figures 2 and 3).
A transverse opening 18 extending across the seat 11 communicates with the rear portion of the shock absorber loading chamber 17 (see FIG. 3).

Next, the support structure of the truck will be explained. 2
0 is a single wide track, which is disposed inside the track housing 2 in the front-rear direction. A drive sprocket (not shown), which is pivotally supported by the frame 1, is disposed on the inner surface of the front end of the track 20. 21, 21a, 21b are a pair of left and right slide rails, and four connecting shafts 22, 2
3, 24, and 25, they are connected integrally and in parallel so as to maintain a narrower width than the track 20.
The connecting shaft 25 at the rear end connects each slide rail 21a, 2
Brackets 26, 26a, 26 fixed to 1b
b, and the adjustment nuts 27, 27
It is movable in the front-back direction by rotation of a and 27b. Guide wheels 28, 28a, and 28b are pivotally supported on the left and right protruding ends of the connecting shaft 25. Also, the second and third connecting shafts 23 and 24 from the front
has suspension wheels 29, 29a, 29
b and 30, 30a, and 30b are pivotally supported.

The slide rails 21a and 21b are attached to the frame 1 so as to be movable up and down by a front link mechanism 40 and a rear link mechanism 50. The front link mechanism 40 includes an arm 41 that is pivotally supported by the frame 1 and extends diagonally rearward, and the rear end of the arm 41 is pivotally connected to the slide rails 21a and 21b via a bracket 42. The rear link mechanism 50 includes a shaft 51 rotatably supported on the frame 1, arms 52, 52a, 52b whose front ends are supported on the shaft 51, and arms 52,
It consists of links 53, 53a, 53b connecting the rear end and the brackets 26, 26a, 26b. A shaft 43 is fixed to the frame 1 above the arm 41 of the front link mechanism 40, and the shaft 43 and the connecting shaft 22 are connected by a band 44. A shock absorber 45 is interposed. Coil torsion springs 46 are attached to the left and right protruding ends of the connecting shaft 23, respectively, and the extending ends of the torsion springs 46 abut on the shaft 43 and the bracket 42, respectively, and the slide rails 21a,
21b has the habit of returning downward. In addition,
A spring load adjustment bolt 47 is provided on the bracket 42, and the torsion spring 46 is attached to this bolt 47.
is in contact with. 48 is a rubber bump stopper that comes into contact with the shaft 43 when the bump is full, and the band 4
Reference numeral 4 serves as a bound stopper, which restricts the vertical movable range of the front end portions of the slide rails 21a and 21b (see FIG. 6). 49,49
a, 49b are idler wheels held on the shaft 43;

On the other hand, both left and right ends of the shaft 51 of the rear link mechanism 50 protrude outside the frame 1, and upwardly extending arms 54a and 54b are spline-coupled to these projecting ends (see FIG. 5). This arm 54a, 5
4b swings together with the arms 52a, 52b and the shaft 51 as the arms 52a, 52b swing. A transverse opening 1 formed in the sheet 11 is provided at the upper end of the arms 54a and 54b.
A connecting rod 55 passing through the inside of the connecting rod 8 is fixed. Note that 56a and 56b are idler wheels held on the shaft 51, and 57 is a reinforcing member for reinforcing each arm 52a and 52b.

Reference numeral 60 denotes a frame 1 in the shock absorber loading chamber 17.
This is a shock absorbing device disposed in the front and back direction along the upper surface of the seat, that is, the seat mounting surface, and this shock absorbing device 6
0 consists of a so-called suspension unit that integrally combines a known shock absorber with a preload gas chamber and a compression coil spring. The front end of the shock absorber 60 is pivotally attached to a bracket 61 fixed to the upper surface of the frame 1 via a patch 61a, and the rear end is pivoted to the connecting rod 55. Note that 62 is a cover that covers each arm 54a, 54b.

In this embodiment, the slide rail 21
a, 21b are given a downward return behavior by the elastic force of the torsion spring 46 and the compressed coil spring of the shock absorber 60, and the truck 20 moves up and down following the ups and downs of the snow surface. At this time, especially in the rear link mechanism 50, the slide rails 21a, 21b
The vertical movement of the rear end is converted into a substantially horizontal movement of the connecting rod 55, and since the shock absorber 60 is arranged horizontally, the rear end of the slide rails 21a, 21b can be moved without significantly reducing the effective thickness of the sheet 11. It is possible to sufficiently increase the vertical movable range at the end. The shock absorber 45 and the shock absorber of the shock absorber 60 have the function of damping vertical vibrations of the slide rails 21a and 21b. Further, as is clear from FIG. 4, in this embodiment, the arm 41 of the front link mechanism 40 is formed so that its front part spreads left and right, and as shown in FIG. Since there is no interference with the front link mechanism 40, the vertical movable range of the front link mechanism 40 is also sufficiently large. Furthermore, in this embodiment, since the shock absorber 60 integrated with the shock absorber is disposed between the seat 11 and the frame 1, snow does not adhere to the compression coil spring of the shock absorber 60 during driving, and for example when the vehicle is left at night. Even in this case, the problem that the compression coil spring of the shock absorber 60 freezes and becomes inoperable does not occur. Furthermore, the buffer device 60
Since this can be regarded as a sprung load, the unsprung load is reduced, the ability of the truck 20 to follow the snow surface is improved, and running stability and riding comfort are further improved.

Next, a second embodiment of the present invention will be described based on FIGS. 7 to 11. FIG. 7 is a side view of the same, FIG. 8 is a longitudinal sectional side view of the main part, FIG. 9 is a longitudinal sectional side view of the main part showing an example of the operating state shown in FIG. 8, and FIG.
FIG. 11 is a partially cutaway plan view taken along the X-ray, and FIG. 11 is an enlarged sectional view taken along the line XI-XI in FIG. In this embodiment, the present invention is applied to a small snow vehicle having two tracks on the left and right sides. In these figures, the same parts as in the first embodiment shown in Figs. 1 to 6 are designated by the same reference numerals, so their description will not be repeated. The skis 6 in this embodiment are attached via leaf springs 6a. The frame 1 has an opening 1a that is long in the front-rear direction and located at the rear of the shock absorber loading chamber 17.
is formed. Track 20 is the 10th and 11th
As is clear from the figure, there are two tracks 20a on the left and right,
20b, these tracks 20a, 20
b is a drive sprocket 7 pivotally supported on the frame 1
0 (see Figures 8 and 9). In the rear link mechanism 50, a shaft 5 to which a pair of left and right arms 52, 52a, and 52b are fixed.
One arm 72 is fixed at the center of the shock absorber loading chamber 17, and this arm 72 extends into the shock absorber loading chamber 17 between the left and right trucks 20a, 20b and through the opening 1a. The rear ends of the arms 52a and 52b are connected by a connecting shaft 73, and a reinforcing member 74 is fixed between the center of the connecting shaft 73 and the arm 72. In this embodiment, the lower end of the link 53 is directly pivoted to the slide rail 21. Further, the guide wheel 28 is connected to each track 20.
Two pieces are held on the connecting shaft 25 corresponding to the numbers a and 20b (see FIG. 11).

The arm 72 corresponds to the arms 54, 54a, and 54b in the first embodiment, and one end of the shock absorber 60 is pivotally attached to the upper end of the arm 72. The structure of this shock absorber 60 will now be explained in more detail with reference to FIG. This shock absorber 60 includes a well-known shock absorber 75 with a preload gas chamber and a compression coil spring 76. The shock absorber 75 includes a cylinder 77, a free piston 78 that is fitted into the cylinder 77 in an airtight and slidable manner to divide the inside of the cylinder 77 into a high pressure gas chamber G and a hydraulic oil chamber R, and one end of a piston rod 79. The operating piston 80 is fixed and slidably inserted into the hydraulic oil chamber R. Then, when the working piston 80 moves, the working oil in the working oil chamber R is
By passing through an orifice (not shown) provided in the actuating piston 80, a damping effect is exerted, and
The change in volume of the piston rod 79 in the hydraulic oil chamber R due to the movement of the piston rod 79 back and forth is compensated for by the movement of the free piston 78.

In this second embodiment, the slide rail 2
1 is given a downward return habit by the elastic force of a torsion spring (not shown) and a shock absorber 60 similar to that of the first embodiment, and the tracks 20a and 20b are prevented from moving when traveling on a snowy surface with many undulations. When a push-up force is applied to the rear part, the arms 52 and 72 of the rear link mechanism 50 swing counterclockwise in the figure around the shaft 51, as shown in FIG. The pushing up force caused by the ups and downs of the snow surface is absorbed by the shock absorber 60. Furthermore, when a pushing force from the snow surface is applied to the front portions of the trucks 20a, 20b, the arm 41 of the front link mechanism 40 swings counterclockwise in the figure around the shaft 43, and at the same time the torsion spring (not shown) ) is deflected. The pushing force exerted by the snow surface is absorbed by the deflection of the torsion spring.

According to the second embodiment, since the arm 72 of the rear link mechanism 50 is configured to pass between the left and right tracks 20a, 20b, the cover 62 covering the arms 54, 54a, 54b as in the first embodiment is This eliminates the need for any protruding objects to the side of the frame 1, which not only improves safety but also prevents the appearance from being impaired. In addition, the transverse opening 18 is not required, and the loss of the sponge 13 on the seat 11 can be minimized, and the riding feeling on the seat 11 is improved.

The present invention is not limited to the first and second embodiments described above, and may be used, for example, when a plurality of shock absorbers 60 are provided.
This also includes the case where it is placed above the . In short, if the shock absorber 60 is arranged in the front-rear direction of the frame 1, the desired effect can be obtained. Although the shock absorber 60 in the above embodiment uses a so-called suspension unit that integrally combines a compression coil spring and a shock absorber, the shock absorber in this invention may be either a suspension spring or a damping device. It may also be configured on the one hand. Furthermore, it goes without saying that the present invention can also be applied to the front link mechanism 40.

As described above, in this invention, a cylindrical shock absorber is arranged so as to be located in the front and back direction almost along the seat mounting surface of the frame, and the shock absorber is connected to the slide rail via a link mechanism so that the shock absorber returns downward. Since the structure is configured to provide a behavior and to provide a damping effect during vertical movement, the structure of the link mechanism etc. inside the truck becomes simple and the number of members to be accommodated in this space is reduced. Therefore, the vertical movable range of the truck can be expanded, and a snowmobile with good stability and good riding comfort can be obtained even on a highly undulating snow surface. Also, since the mechanism inside the truck is simpler, snow and ice are less likely to stick there. Furthermore, since the reaction force of the shock absorber is applied in the longitudinal direction of the frame, which is long in the front and back direction,
Effects such as almost no need for reinforcement to increase the rigidity of the frame can be obtained.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, FIG. 1 is a side view thereof, FIG. 2 is a vertical sectional side view of the main part, FIG. 3 is a sectional view taken along the - line, and FIG. FIG. 5 is a plan view, FIG. 5 is a sectional view taken along the - line, and FIG. 6 is a side view showing a full bump state. Figures 7 to 11 are the second
7 is a side view thereof, FIG. 8 is a vertical sectional side view of the main part, FIG. 9 is a vertical sectional side view of the main part showing an example of the operating state of FIG. 8, and FIG. 10 is a side view of the main part. of-
A partially cutaway plan view seen from the line, Figure 11 is the 10th
It is an enlarged sectional view taken along the line XI-XI in the figure. 1... Frame, 20, 20a, 20b... Track, 21, 21a, 21b... Slide rail, 28, 28a, 28b... Guide wheel,
50...Link mechanism, 60...Buffer device, 70...
...Drive sprocket.

Claims (1)

[Claims] 1. A drive sprocket pivotally supported on a frame;
a slide rail extending in the front-rear direction and held vertically movably below the frame; a guide wheel rotatably supported on the rear end of the slide rail; and the drive sprocket, the slide rail, and the guide wheel. In a small snowmobile equipped with a truck that is hung around the frame, a cylindrical shock absorber is disposed in the front-rear direction substantially along the seat mounting surface of the frame, and vertical movement of the slide rail causes the shock absorber to expand and contract. A small snowmobile, characterized in that the slide rail is connected to the shock absorber via a link mechanism so as to allow the slide rail to move.