JPS6345358B2 - - 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.

Conventionally, most suspension systems for steering skis on small snowmobiles have been roof spring type suspension systems. 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.

Recently, attempts have 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. If the torsion bar is connected directly, there is a problem that the steering rotation will be restricted.

The present invention has been made based on the above circumstances, and the torsion bar is connected to the strut, and in this case, the torsion bar is configured to effectively receive the axial displacement of the strut, but to allow rotation of the steering ski. An object of the present invention is to provide an anti-roll device for a small snowmobile, which can fully utilize the original function of a torsion bar and reliably stabilize the attitude of the vehicle body.

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 attached to the main frame 1 via links 15, 16, a damper 17, and a spring (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. 4, and a metal runner 20 is fixed to the bottom sliding surface of the skis 18, 18. 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 predetermined 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 the cross member 31 is connected and supported to the main frame 1 by arms 32, 32. As shown in FIG. 3, the holder 30 includes a hydraulic damper 33 as a strut.
is slidably penetrated 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 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 snow and ice are scraped off using the webbed lip 38a, and the oil seal lip 38b is removed. Prevents damage. 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 in the lower part 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 in the direction of extending the piston rod 41 and prevents the piston rod 41 from entering 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. 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 upper end of the piston rod 41 faces the opening 49. 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. The outer race of the thrust bearing 52 is coupled 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 rotatably attached to the upper end of the cylinder 34. The spring receiving seat 54 is integrally fixed to the outer races of the thrust bearings 47, 47, and the inner races of the thrust bearings 47, 47 are fixed to the upper end of the cylinder 34. Therefore, the spring receiving sheet 54 is rotatable relative to the cylinder 34, in other words, the spring receiving seat 54 is rotatable relative to the cylinder 34.
Even if the spring bearing seat 54 is rotated around its central axis 0-0, the spring receiving seat 54 does not rotate.

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.
Since the piston rod 41 is held on the vehicle body side via the casing 48, 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 lower 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 connected to the cylinder 3.
It is perpendicular to the central axis 0-0 of 4.

80 is a torsion bar constituting the anti-roll device. This torsion bar 80 has a straight rod shape, is located at the rear part of the engine room 4, and is suspended horizontally in the left and right direction, as shown in FIG. Mounting is supported. The rear ends of arms 83, 83 are integrally connected to both ends of the torsion bar 80, for example, by serration engagement. The lower end of a rod 85 is connected to the tip of this arm 83 via a support shaft 84. The upper end of the rod 85 is connected via another support shaft 86 to a connecting rod 87 as a connecting member. The connecting rod 87 is welded to the lower spring receiving sheet 54 described above. Therefore, the connecting rod 87 moves integrally with the cylinder 34 following the vertical movement of the cylinder 34, but does not follow the rotation of the cylinder 34 due to the presence of the thrust bearings 47, 47. It's summery. A guide groove 88 is opened in the rear wall of the casing 48 along the axial direction, and the connecting rod 87 passes through this guide groove 88 so that it can be slid along the guide groove 88. There is. Note that the guide groove 8 in the connecting rod 87
It is recommended that a slider (not shown) made of nylon or the like be applied to the area where it comes into sliding contact with 8.

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

When the steering handle 61 of the steering device 60 is rotated, the steering arm 66 is rotated via the pitman 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
0, and the upper end of this cylinder 34 is elastically pushed by a compression spring 55, so that the ski 18
It also moves up and down along the central axis 0-0 of the attenuator 33. As a result, even if the ski 18 follows the unevenness of the snow surface, since the cylinder 34 moves up and down relative to the holder 30, in other words, the vehicle body, 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 relative to each other, but this variation is absorbed by the rotation of the fulcrums of the respective axes of the links 67 and 69. Each spindle 6
8, 70, 71 are perpendicular to the center axis 0-0 of the attenuator 33, so the links 67, 69 are aligned with the center axis 0-0.
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 tends to sink into the vehicle body more than the inner ski 18 due to centrifugal force, that is, the outer damper 33 tends to slide upward to a large extent. The upward movement of the cylinder 34 in this attenuator 33 is
The force is transmitted to the connecting rod 87 through the lower spring receiving sheet 54, and the connecting rod 87 is moved upward along the guide groove 88. Movement of connecting rod 87 is done by rod 8.
It is transmitted to the torsion bar 80 through the fifth arm 83. In the case of the torsion bar 80, since the rotational forces at the left and right ends are different, a torsional stress is generated, and the upward sliding movement of the connecting rod 87 is restrained by this torsional stress. Therefore, the damper 33, that is, the cylinder 34, is prevented from moving significantly upward, and as a result, the vehicle body is prevented from rolling outward. This prevents the vehicle body from tilting when turning, allowing the vehicle to turn in a stable posture.

However, in the above configuration, the steering device 60
Since the connecting rod 87 is rotatably attached to the cylinder 34 which is rotated integrally with the steering skis 18, 18 by
is not restrained by the torsion bar 80. Moreover, since the connecting rod 87 is integrally linked to the vertical movement of the cylinder 34 and transmits this linkage to the torsion bar 80, the torsion bar 80 receives the vertical movement of the steering ski 18 with high precision, and therefore the torsion bar 80 Torsional stress causes steering skis 18
respond sensitively to Therefore, the original function of the torsion bar can be fully demonstrated.

The torsion bar 80 is not limited to a straight bar shape, but may be curved into a conventionally known U-shape.

According to the present invention described in detail above, the torsion bar is supported on the vehicle body side, and the connecting member is attached to the upper part of the strut, which is supported by a holder on the vehicle body side so as to be movable around the axis and movable up and down. Since the torsion bar is mounted with only rotation allowed around its axis and both ends of the torsion bar are connected to this connecting member, vertical movement of the steering ski can be transmitted to the torsion bar with high precision. Therefore, the torsion bar restricts the movement of the strut in the axial direction by its torsional stress.
It prevents the vehicle body from rolling when turning and maintains a stable driving posture. Further, since the torsion bar allows the steering rotation of the steering ski, it has the advantage that it does not interfere with the steering operation in any way.

[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 the engine room, Fig. 3 is an enlarged side view showing a main part in section, and Fig. 4. and FIG. 5 are sectional views taken along lines - and - in FIG. 3, respectively. 1... Main frame, 18... Steering ski,
30...Holder, 34...Cylinder (strut), 47...Bearing, 55...Coil spring,
60... Steering device, 80... Torsion bar, 8
3... Arm, 85... Rod, 87... Connecting rod.

Claims (1)

[Scope of Claims] 1 A pair of left and right struts are supported in a holder provided on the vehicle body so as to be rotatable around their axes and movable up and down, and a steering ski is connected to the lower end of each of these struts. , in a small snow vehicle in which the vertical struts are rotated by a steering device so that the steering skis are operated together with the struts, a torsion bar is supported on the vehicle body side, and a torsion bar is supported above the holder. An anti-roll device for a small snowmobile, characterized in that a connecting member is attached to the upper part of a strut protruding from the strut in a state that only allows rotation in the direction around the axis of the strut, and both ends of a torsion bar are connected to the connecting member. .