JPS6345357B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-roll device for stabilizing the attitude of a small snowmobile in which steering skis are supported by a strut-type suspension system.

Leaf spring suspension systems have conventionally been the majority of suspension systems for steering skis on small snowmobiles. Although the leaf spring type suspension system has a simple structure, since the deflection stroke of the leaf spring is relatively small, it cannot effectively absorb the unevenness of the snow surface, and the ride quality is insufficient.

Therefore, attempts have recently been made to employ a so-called strut-type suspension system in which a steering ski is connected to the lower end of a strut that is pressed downward by a coil spring. This allows the suspension stroke to be set large, making it difficult for the unevenness of the snow surface to be transmitted to the vehicle body, resulting in a more comfortable ride. However, since this type of strut suspension system has a large suspension stroke, the vehicle body rolls significantly outward when subjected to centrifugal force during cornering, making the vehicle's posture unstable, especially when cornering at high speeds.

For this reason, it is conceivable to adopt a torsion bar type stabilizer as an attitude stabilizing means, that is, an anti-roll device, in a small snowmobile equipped with this type of strut suspension system. However, since the torsion bar uses torsional stress to balance the inclination of the left and right skis, it is desirable to attach both ends of the torsion bar directly to the steering ski, but the direction of the steering ski can be changed by the steering device. Therefore, if the torsion bar is connected directly, there is a problem that the steering rotation of the ski will be restricted.

The present invention was developed based on the above circumstances, and it fully demonstrates the original function of the torsion bar without significantly interfering with the steering operation of the steering ski, and also automatically controls the steering ski during rolling. It is an object of the present invention to provide an anti-roll device for a small snowmobile that can improve safety by preventing rolling by returning the snowmobile to a rotational direction in a straight running direction.

An embodiment of the present invention will be described below based on the drawings.

In the figure, 1 is a main frame constituting the vehicle body, and a bottom cover 2 is connected to the front end of the main frame 1. The bottom cover 2 is covered with a shroud 3, and these bottom covers 2
An engine room 4 shown in FIG. 2 is constructed between the engine compartment and the shroud 3. For example, an air-cooled two-stroke two-cylinder engine 5 is housed in the engine room 4 . 6 is the intake pipe, 7 is the exhaust pipe,
8 indicates a muffler. The engine 5 is a V not shown.
A belt automatic transmission is provided, and a sprocket wheel (not shown) is driven through this transmission.

A windshield body 9 is provided at the rear end of the shroud 3. Further, a seat 10 is mounted on the main frame 1, and a cargo box 1 is mounted at the rear end of this seat 10.
1 is provided. Reference numeral 12 designates an endless track (hereinafter referred to as a track), the front end of which is wound around the sprocket foil, and the rear end of which is wound around the guide wheel 13. The inner surface of the track 12 is adapted to be in sliding contact with a guide rail 14.
4 is elastically supported by the main frame 1 via links 15, 16, an attenuator 17, and springs (not shown).

Reference numerals 18 and 18 denote a pair of left and right steering skis disposed below the bottom cover 2, which are urged downward and held by strut suspension devices 19, 19. The skis 18, 18 are formed to be convex downward as shown in cross section in FIG. 5, and a metal runner 20 is fixed to the bottom sliding surface thereof. A cover 21 having a substantially dome-shaped cross section is attached to the ski 18. This cover 21 is provided with an opening 22, and a connecting plate 23 is fixed to the inner surface of the cover 21 corresponding to this opening 22 for reinforcing purposes. A bracket 26 is rotatably attached to the cover 21 and the connecting plate 23 via a support shaft 24 and a collar 25. The lower surface of the bracket 26 is convex downward as shown in FIG. 3, and a rubber damper 27 is installed between this lower surface and the ski 18. Since the ski 18 is pivotally supported by the support shaft 24 to the bracket 26, it can swing in the direction of the arrow A in FIG. There is.

To explain the strut suspension system 19,
Reference numeral 30 is a cylindrical holder, and the central axis of this holder 30 is inclined upward and backward.
It is arranged so that a positive caster angle α can be set with respect to the vertical line. As shown in FIG. 2, the holder 30 is welded to both ends of a cross member 31 disposed across the engine room 4. Note that arms 32, 32 of the cross member 31 are connected and supported to the main frame 1. As shown in FIG. 3, a hydraulic damper 33 as a strut is passed through the holder 30 so as to be slidable in the vertical direction. That is, the strut is connected to the cylinder 34 of this damper 33.
This cylinder 34 is rotatably and vertically supported by bearing metals 35 and 36 provided at the upper and lower ends of the holder 30. Seal materials 37 and 38 are provided above and below the bearing metals 35 and 36 to seal the gap between the holder 30 and the cylinder 34. The lower end sealing material 38 has an ice scraping lip 38a extending downward and an oil sealing lip 38 extending upward.
b is formed. In the cylinder 34, a portion extending downward from the holder 30 is exposed to the outside, and since snow and ice adhere to this exposed portion, the ice scraping lip 38a is used to scrape off the snow and ice, and the oil seal lip 38b is removed. This prevents damage to the product. Note that a grease chamber 39 is formed between the bearing metals 35 and 36.

A piston 40 is slidably fitted into the damper 33. A piston rod 41 is connected to the piston 40.
1 extends upward from the cylinder 34. A free piston 42 is slidably fitted into the lower end of the cylinder 34, and a gas chamber 44 separated from an oil chamber 43 is formed below the free piston 42. Nitrogen gas is sealed in the gas chamber 44 at a high pressure higher than atmospheric pressure, and this gas pressure applies an initial load to the piston rod 41 in the direction of extension, and also prevents the piston rod 41 from penetrating into the cylinder 34. This compensates for the accompanying volume increase.

The cylinder 3 in such a damper 33
The lower end of the ski 4 is fixed to a bracket 26 on the ski 18 side. That is, the lower end of the cylinder 34 is fitted into the bracket 26, and by tightening the nuts 45, the cylinder 34 is attached to the bracket 26.
6 is integrally joined.

A connecting collar 46 is welded to the upper end of the holder 30. Air and water drainage holes 47 are opened in this connecting collar 46 . A cylindrical casing 48 is coupled to the connecting collar 46 . An opening 49 is provided in the center of the upper end surface of the casing 48, and the piston rod 4 is inserted into this opening 49.
The top of 1 is facing you. A spring receiving seat 50 is attached to the upper end of the piston rod 41, and a stopper 51 made of rubber is fixed to this spring receiving seat 50. Further, the inner race side of a thrust bearing 52 is fixed to the spring receiving seat 50. Thrust bearing 5
The second outer race is connected to the upper end surface of the casing 48 via a baked annular elastic member 53. Therefore, the piston rod 41 is rotatably held relative to the casing 48, in other words relative to the vehicle body. A spring receiving seat 54 is attached to the upper end of the cylinder 34. A coiled compression spring 55 is spanned between this spring receiving seat 54 and the spring receiving seat 50 at the upper end of the piston rod 41. The piston rod 41 is connected to the casing 4
Since the cylinder 34 is held on the vehicle body side via the spring 8, the cylinder 34 is always pushed downward by the biasing force of the compression spring 55.

On the other hand, the steering skis 18, 18 are steered by a steering device 60. To explain the steering device 60, reference numeral 61 is a steering handle provided in front of the seat 10, and is connected to the upper end of a handle column 62. A pitman arm 63 is connected to the upper end of the handle column 62, and left and right tie rods 6 are attached to this pitman arm 63.
4 are connected. The tie rod 64 is connected to a steering arm 66 via a ball joint 65. The steering arm 66 is rotatably attached to the outer periphery of the holder 30, and its rear end is connected to the tie rod 64 via a ball joint 65.

A link 67 is connected to the support shaft 6 at the front of the steering arm 66.
8 and are rotatably connected. The upper end of another link 69 is rotatably connected to the tip of this link 67 via a support shaft 70. The lower end of the other link 69 is rotatably connected to the bracket 26 on the steering ski 18 side via a support shaft 71. Each of the above-mentioned support shafts 68, 70 and 71
are parallel to the support shaft 24 that connects the bracket 26 and the ski 18 to each other, and each of these support shafts 68, 70, 71 and 24 is parallel to the center axis O-O of the strut which also serves as the damper 33. It is now perpendicular to .

80 is a torsion bar as an anti-roll device. This torsion bar 80 is curved into a substantially U shape and is arranged on the outside of the lower surface of the bottom cover 2 so as to surround the bottom cover 2. The torsion bar 80 is supported by the bottom cover 2 via a support fitting 81 and an elastic member 82. The rear end of the torsion bar 80 is connected to the bracket 26 on the ski 18 side via a rod 83. The connection structure between the torsion bar 80 and the rod 83 is shown in FIG. 6, and an elastic member 84 is interposed between the rod 83 and the eye of the torsion bar 80. In addition, 85, 85 is a stopper, 86
indicates a rubber cover. The lower end of the rod 83 is connected to the bracket 26 by ball joint means. That is, the support shaft 71 connecting the link 69 and the bracket 26 has a ball portion 87 formed at one end, and the lower end of the rod 83 is connected to the ball portion 87.
It is fitted so that it can swing freely. Note that 88 indicates a rubber cover. Further, the rod 88 is connected to the torsion bar 80 and the bracket 26 in a turnbuckle shape so that the distance between them can be adjusted.

By the way, since the lower end of the rod 83 is connected to the bracket 26 via one end of the support shaft 71, the main frame is 1
It is located eccentrically outward in the width direction.
In this case, the central axis O-O has a positive caster angle α
Therefore, the plane perpendicular to the central axis O--O, that is, the plane passing through the line P--P in FIG. 3, is an inclined plane with the front facing upward with respect to the horizontal plane. In the plane along this inclined plane P-P, as shown in FIG. It is also provided eccentrically to the outside in the width direction of the main frame 1 from the center line X-X along the front-back direction passing through the central axis O-O of this attenuator 33, The lower ends of these left and right rods 83 are provided at positions that are symmetrical to each other.

The operation of the embodiment having the above configuration will be explained.

When the steering handle 61 of the operating device 60 is rotated, the steering arm 66 is rotated via the Bitmann arm 63, tie rod 64, and ball joint 65. Links 67 and 69 are connected to the front surface of the steering arm 66 via support shafts 68 and 70, respectively, which are orthogonal to the cylinder 34 of the damper 33. Therefore, the links 67 and 69 are also connected to the steering arm 6.
It can be rotated in the same direction as 6. and link 6
9 is transmitted to the bracket 26 via a support shaft 71 perpendicular to the cylinder 34. The cylinder 34 connected to the bracket 26 is rotatably supported by the holder 30, and the piston rod 41 is rotatably supported by the casing 48, so the damper 33 as a strut is connected to the bracket 26. They are rotated together, and at the same time, the skis 18 are also rotated together. Therefore, the snowmobile must be steered.

On the other hand, the cylinder 34 of the attenuator 33 is connected to the holder 3
Since the upper end of this cylinder 34 is elastically pushed by a compression spring 55, the ski 18 is supported so that it can move up and down with respect to the cylinder 34.
At the same time, the attenuator 33 moves up and down along the central axis O-O. As a result, even if the ski 18 follows the unevenness of the snow surface, the cylinder 34 moves up and down relative to the holder 30, in other words, the vehicle body, so that the unevenness of the snow surface is less likely to be transmitted to the vehicle body. At this time, the distance between the steering arm 66 and the bracket 26 changes relatively, but this fluctuation is absorbed by the rotation of the respective axes of the links 67 and 69. Each spindle 6
8, 70, 71 are perpendicular to the central axis O-O of the attenuator 33, so the links 67, 69 are perpendicular to the central axis O-O of the attenuator 33.
The ski 18 moves within a plane passing through the ski 18, and the ski 18 does not change its steering angle due to its vertical movement.

Since the links 67 and 69 are located in front of the portion of the attenuator 33 that is exposed below the holder 30, even if an obstacle exposed on the snow surface tries to hit the attenuator 33 while driving, the links 67 and 69 will not be connected. 6
7 and 69 to prevent the attenuator 33 from being damaged or damaged.

However, when turning, if the outer ski 18 attempts to sink into the vehicle body to a greater extent than the inner ski 18 due to centrifugal force, that is, if the outer damper 33 attempts to slide upward to a greater extent, the outer bracket 26 transmits the above sliding amount to the torsion bar 80 via the rod 83. Since one end of the torsion bar 80 is pushed up significantly, torsional stress is generated between the torsion bar 80 and the other end. This torsional stress prevents the outer damper 33 from sliding upward and attempts to pull the inner damper 33 upward. Therefore, the sliding protrusion amounts of the left and right dampers 33, 33 are balanced, and the heights of the skis 18, 18 are balanced, so that the vehicle body does not roll significantly outward.

By the way, both ends of the torsion bar 80 are connected to the bracket 26 via rods 83.
As shown in FIG. 7, this connection position is relative to the center axis O-O
They are eccentric to the outside in the width direction of the main frame 1 from the center line XX in the front-rear direction passing through the center axis OO, and are symmetrical to each other. Therefore, when the bracket 26 is rotated by operating the handle during turning, the rod 83
The lower end of can also be rotated integrally. Now, in FIG. 7, it is assumed that the bracket 26 is rotated in the direction of arrow B. Rod 83 and bracket 26
The connection point of is on a plane passing through the line P-P, and this plane is perpendicular to the central axis O-O of the attenuator 33, and this central axis O-O has a positive caster angle α. Therefore, the plane passing through the P-P line is a plane that is inclined forward and upward with respect to the horizontal plane.

Therefore, when the bracket 26 is rotated in the direction of arrow B, the left rod 83 moves to the inclined plane P-
The rod 83 on the right side will go down along the slope P--P. As a result, when turning, the ends of the torsion bars 80 located on the outside are pushed upward, and the ends of the torsion bars 80 located on the inside are pulled down. These pushing-up forces and pulling-down forces return stress to the torsion bar 80 and generate a reaction force, which tends to push down the outer bracket 26 and pull up the inner bracket 26.
These forces are added to the aforementioned forces that slide the outer damper 33 downward and pull the inner damper 33 up. The force at both ends of the torsion bar 80 is a force that causes the brackets 26, 26 to return in the direction opposite to the direction of arrow B, since the plane including the line PP is inclined. The handle 61 is therefore automatically returned. In other words, if you try to turn suddenly, the handle 61 will automatically return to its original position due to the torsion stress of the torsion bar 80, and this will also eliminate the generation of large centrifugal force, thereby preventing an unstable running posture. can do.

Note that when the bracket 26 is rotated in the direction of arrow B, this rod 83 is attached to the upper and lower ends of the rod 83.
The lower end of the rod 83 is ball jointed to the ball 87, and the upper end is connected to the torsion bar 80 via an elastic member 84.
Since the upper and lower ends are connected to each other, the above-mentioned torsion is absorbed at the connecting points at the upper and lower ends. Furthermore, although the lower end of the rod 83 is eccentric from the center axis O-O, the amount of eccentricity is not large, so at most the upper and lower ends of the rod 83 can be sufficiently absorbed by the connecting portions of the upper and lower ends. It does not interfere with operation.

Further, since the torsion bar 80 is arranged outside the bottom cover 2 so as to surround the bottom cover 2, it functions as a bumper when the torsion bar 80 collides with an obstacle. Furthermore, the torsion bar 80 can be grasped to lift the vehicle body, and has the advantage that it can also be used as a handle when changing directions.

In the above embodiment, the torsion bar 8
0 is connected to the bracket 26 via the rod 83, but the rod 83 is omitted and the torsion bar 80 is used instead.
Alternatively, both ends of the bracket 26 may be directly connected to the bracket 26.

As detailed above, in the present invention, both ends of the torsion bar are connected to the pair of left and right struts at positions that are eccentric to the outside in the width direction of the vehicle body from the center axis of the struts and are symmetrical to the left and right sides of the struts. The displacement of the strut when it slides in and out is
The power is transmitted directly to the torsion bar, and therefore the torsion bar's original function is fully demonstrated, balancing the amount of protrusion of the left and right steering skis, preventing the vehicle from rolling, and maintaining a stable posture.

Moreover, since the torsion bar is connected at an eccentric position as described above with respect to the strut with the positive caster angle corrected, when the steering ski is rotated, the strut is automatically rotated from the torsion bar. You will be given the power to recover. For this reason, the steering skis try to return to the straight running direction, which causes the vehicle body to return to its turning direction, thereby eliminating the centrifugal force, which also prevents rolling and enables safe driving. It can be done.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a side view of a small snowmobile, Fig. 2 is a plan view of its engine room, Fig. 3 is an enlarged side view showing a main part in section, and Fig. 4 The figure is a front view, and FIGS. 5 and 6 are sectional views taken along lines - and - in FIG. 3, respectively.
FIG. 7 is a layout diagram showing a plane including the line P--P for explaining the operation. 1... Main frame, 18... Steering ski,
34...Cylinder (strut), 55...Coil spring, 60...Steering device, 80...Torsion bar, 83...Rod.

Claims (1)

[Scope of Claims] 1. A pair of left and right struts forming a positive caster angle are pressed and biased so as to protrude downward by a coil spring provided on the vehicle body side, and the struts are rotated around the central axis of the struts relative to the vehicle body. In a small snow vehicle which is rotatably mounted and a steering ski is connected to the lower end of these struts so that these struts can be rotated by a steering device, both ends of a torsion bar supported on the vehicle body are
Anti-roll of a small snowmobile, characterized in that the pair of left and right struts having a positive caster angle are connected eccentrically outward in the axial direction of the vehicle body from the central axis of the struts and at symmetrical positions. Device.