JPH0584273B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a running device for a balloon tire vehicle, and in particular to the arrangement of its tires.

b. Prior Art Among saddle-type four-wheeled vehicles that are vehicles for traveling in fields or mountains, some are equipped with balloon tires (these are called balloon-tire vehicles).

FIG. 1 is a perspective view showing the frame and balloon tire of a balloon tire vehicle.

The balloon tire vehicle shown in FIG. 1 is a four-wheel vehicle with rear wheel drive and front wheel steering. Due to its purpose, this balloon tire vehicle is required to be lightweight and structurally simple. Furthermore, since the balloon tire itself has impact force absorption properties, the rear wheel suspension system has a relatively simple structure.

2 is a side view conceptually showing the frame and tire of FIG. 1. FIG.

The rear wheel 1 has an axle 3 rotatably attached to a swing arm 2. The swing arm 2 is attached to the vehicle body frame 4 so as to be rotatable in the vertical direction about a rotation shaft 5. The swing arm 2 consists of two arms, one for the right rear wheel and one for the left rear wheel, and one bridging member 6 that bridges the two arms, and the bridging member 6 and the vehicle body frame. 4 are connected by a suspension system.

As a result, the right rear wheel and the left rear wheel move in conjunction with each other to rotate about the rotation axis 5. In other words, the left and right rear wheels cannot move up and down independently. However, as mentioned above, since the balloon tire itself has impact force absorbing properties, no problem occurs during normal driving. At this time, the larger the balloon tire is, the more effective the impact force absorption ability of the balloon tire is, so it is preferable for the balloon tire to have a larger diameter and tire width. Therefore, wide balloon tires are used for balloon tire vehicles. For the above reasons and in consideration of ease of steering, balloon tire vehicles are designed to have wide rear wheels.

JP-A-59-167333 describes a straddle-type four-wheel vehicle in which the tire widths of the two front wheels are approximately equal to the width of the rear two wheels, and the overall width of the two front wheels is slightly larger than the overall width of the rear two wheels.

In a balloon tire vehicle where the front and rear wheels have approximately the same tire width and tire spacing, the front wheels will trample the uneven ground, and the rear wheels will run in the ruts of the front wheels. As a result, the rear wheels become slippery, resulting in insufficient driving force, and the vehicle also runs over the same ruts, making it difficult to steer. To solve this problem, there is a balloon tire vehicle in which the width of the front two tires is smaller than the width of the rear two tires.

c. Problem to be solved by the invention When the tire width of the front two wheels becomes smaller than the tire width of the rear two wheels, the driving force and maneuverability are improved, so the balloon tire vehicle can be used on more difficult rough terrain. .

Figure 3 is a plan view showing the arrangement of tires when a balloon tire vehicle according to the prior art is traveling in the direction of the arrow on a mountain road between cliffs on the mountain and valley sides, and Figure 4 is the arrangement of tires as shown in Figure 3. is an elevational view of the vehicle seen from the rear.

When driving on such mountain roads, the cliffs on the valley side are dangerous, so drivers tend to drive close to the cliffs on the mountain side. In such a case, the rear wheel 1 may come into contact with the lower end of the mountain cliff as shown in FIGS. 3 and 4. If they make contact, not only will the sides of the balloon tire 1 be abraded, but an external force will be applied to the vehicle from the side, causing the vehicle to shake and become unstable.

Figure 3 shows that when the tires come into contact with the cliff on the mountain side, a lateral external force F acts, and a moment _Mz is generated around the vertical axis passing through the center of gravity. Figure 4 shows that the same external force produces a moment M _y around the longitudinal axis passing through the center of gravity.

FIG. 5 is a plan view showing the arrangement of tires of a balloon tire vehicle traveling in the direction of an arrow in a field with rough terrain.

When the rear tire 1 runs onto a large stone or stump 7 on the field, there is a limit to the ability of the balloon tire to absorb the impact force, and the suspension system of the rear wheel is the
As shown in FIGS. 2 and 2, the rear part of the balloon vehicle swings significantly up and down or left and right.

In order to avoid such rocking, it is sufficient to prevent the tire from coming into contact with the lower end of the valley on the mountain side, large stones, or stumps. However, although the front wheels of a balloon vehicle can be visually checked to prevent them from coming into contact with the obstacles, the rear wheels tend to do so.

An object of the present invention is to provide a traveling device for a balloon vehicle that allows the outer side of the rear wheels to also pass without contacting obstacles when the front wheels are maneuvered so as to pass through the obstacles without contacting them.

d Means for Solving the Problems The above-mentioned problems of the present invention were solved by making the full width of the front wheel, that is, the distance between both outer side surfaces of the tire, narrower than the full width of the rear wheel.

FIG. 6 is a conceptual plan view showing an example of tire arrangement according to the present invention. Here, the forward direction of the vehicle is indicated by an arrow.

The above conditions can be expressed as follows using the tread width of the wheel and the width of the tire.

As shown in Fig. 6, the total width of the front wheels 8 and 9 is W _f ,
The tire width is B _f , the tread width is T _f , and the rear wheel is 10,
The overall width of 11 is w _f , the tire width is b _f , and the tread width is t _f
shall be.

Since W _f = T _f + B _f w _f = t _f + b _f holds, when W _f > w _f , T _f + B _f > t _f + b _f , that is, from the sum of the front wheel tread width and front tire width, the rear wheel The above condition is satisfied when the sum of the tread width of the rear tire and the width of the rear tire is small.

e Effects of the invention The total width of the front wheels is wider than the total width of the rear wheels, so when you discover an obstacle in front of you, if you maneuver so that the front wheels do not come in contact with the obstacle, the rear tires will change as long as you are moving in an almost straight line. The outside will not touch the obstacle. That is, if the front wheels can pass, the rear wheels can also pass.

Furthermore, since the overall width of the rear wheels is narrow, there is little difference in path between the left and right wheels, and the amount of slip is small. Therefore, even a balloon tire vehicle that is not normally equipped with a differential device can easily turn.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the frame and balloon tire of a balloon tire vehicle, Fig. 2 is a side view conceptually showing the frame and tire in Fig. 1, and Fig. 3 is a conventional balloon tire vehicle with mountain sides and valleys. A plan view showing the arrangement of tires when driving in the direction of the arrow on a mountain road between side cliffs, Figure 4 is an elevation view of the arrangement shown in Figure 3 seen from the rear of the car, and Figure 5 is FIG. 6 is a conceptual plan view showing an example of the tire arrangement according to the present invention.

Claims (1)

[Scope of Claims] 1. A balloon tire vehicle equipped with balloon tires on two front wheels and two rear wheels, and a swing arm in which the two rear wheels are rotatably fixed to a vehicle body frame on a lateral horizontal rotation axis at the rear of the vehicle. A running system for a balloon tire vehicle supported by a balloon tire and steered using the front two wheels, characterized in that the tire width of the front two wheels is smaller than the tire width of the rear two wheels, and the total width of the front two wheels is larger than the total width of the rear two wheels. A running device for a balloon tire vehicle.