JPH0637189B2 - Front frame lean type tricycle - Google Patents

Description

The present invention relates to a front frame lean type three-wheeled vehicle in which a rider can lean and control the body.

For a three-wheeled motor vehicle, use a lean front frame to improve steering stability at high speeds. As shown in FIG. 1, the front frame lean type three-wheeled vehicle includes a front frame 1 having a front wheel 4 which can be steered by a steering wheel 3 and a seat 5 on which a rider rides, and left and right rear wheels 6. The rear frame 2 supported by the roll frame 7 is fixed to the front frame 1 and the bearing member 8 fixed to the rear frame 2 so as to swing freely. A bearing member may be fixed to the front frame 1 and a roll shaft may be fixed to the rear frame 2. By making the front frame 1 lean in this manner, the rider can corner by a rapid movement of the center of gravity as in a motorcycle, and can obtain steering stability at high speed.

However, the above configuration has a drawback that the rear wheel changes its direction when the front frame leans, which affects the steering characteristics. As shown in FIG. 1, if the axis 9 of the roll shaft 7 is set horizontally, the roll shaft 7 passes above the ground contact point 10 of the front wheel 4. Leaning of the front frame 1 is substantially performed around a line 11 connecting the ground point 10 and the bearing portion of the roll shaft 7. Therefore, the axis 9 moves along the conical surface inclined by the angle α about the line 11, and when observing this in a plane,
By tilting to the right as shown in FIG. 3 from the upright state of FIG. 2, the shaft center 9 swings the front to the right, and the rear wheel 6 also turns to the right. Lean to the left to turn to the left.

In this way, when the vehicle body is tilted, the rear wheel 6 changes direction
Generally, it makes the steering operation unstable. In particular, as in the above example, when the axis 9 passes above the ground contact point 10, the lean direction and the turning direction of the rear wheel 6 become the same, so there is a concern that the turning radius of the cornering will unintentionally increase. In extreme cases, leaning immediately before steering may cause the vehicle to turn in the opposite direction for a moment. In order to prevent the above phenomenon, the axis 9 may be aligned with the line 11 or may pass below the grounding point 10. However, the center axis 9 becomes considerably downward, and when leaning, the rider feels that he is leaning forward with braking. This point can be prevented by installing the roll shaft 7 at a low position and reducing the inclination angle, but this is not preferable in practice because the ground clearance becomes low.

An object of the present invention is to improve the above various problems.
An object of the present invention is to provide a front frame lean type three-wheeled vehicle which automatically corrects the rear wheel deflection caused by lean so as not to affect the steering characteristics.

The outline of the present invention for achieving the above object is to axially rotatably couple a front frame supporting steerable front wheels and a rear frame supporting left and right rear wheels by a roll shaft in the front-rear direction and a bearing member thereof. The left and right rear wheels are supported by the knuckle shaft so that they can turn to the left and right, and the rotational displacement of the front frame relative to the rear frame about the roll axis is transmitted to the rear wheels via tie rods, knuckle arms, etc. By this, the direction of the rear wheel with respect to the rear frame is controlled in association with the rotational displacement of the front frame, and the direction of the rear wheel is displaced in the same phase as or the opposite phase to the rotational displacement direction of the front frame. The means for transmitting the rotational displacement of the front frame to the lateral displacement of the tie rod uses a combination of a rack and a pinion or a link mechanism.

With this configuration, even if the front frame leans and the rear frame changes its direction in the left-right direction, only the rear wheels maintain the traveling direction with respect to the ground until immediately before. Alternatively, the turning direction and turning angle are positively controlled, for example, the direction of the rear wheel with respect to the rear frame is controlled in the opposite phase direction or the same phase direction with respect to the rotational displacement direction (lean direction) of the front frame, The steering characteristic can be improved. Therefore, in order to prevent the phenomenon of the rear frame sideways, it is not necessary to take measures such as setting the roll shaft axis downward or setting it low, and it does not cause a separate inconvenience due to this measure, in other words, make the roll shaft horizontal or upward. Alternatively, by taking the ground clearance sufficiently, it is possible to actively take advantage of the secondary advantages.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a plan view of the rear frame when the front frame is upright, FIG. 5 is a plan view of the front frame when leaning to the right, and FIG. 6 is an enlarged view around the roll axis as viewed from the arrow AA of FIG. FIG.

The roll shaft 7 is fixed to the front frame and is supported by a bearing member 8 provided on the rear frame 2. The axis of the roll shaft 7 is substantially horizontal. The rear wheel 6 is rotatably supported by a knuckle shaft 12 on a part of the rear frame 2 and has a knuckle arm 13. The outer end of the tie rod 14 is connected to the tip of the knuckle arm 13. 15 indicates an engine. The engine 15 is of the power unit type and is incorporated as part of the rear frame 2. The power of the engine 15 is transmitted to the rear wheels 6 by the rear axle 16.

The roll shaft 7 projects rearward from the rear end of the bearing member 8 and the pinion 17 is fixed. The pinion 17 meshes with a rack bar 18 placed below it. The rack bar 18 is axially supported by the rear frame 2 so as to be slidable from side to side, and the inner ends of the tie rods 14 are connected to both ends.

As shown in Fig. 5, the line where the front frame passes through the front wheel ground contact point
When leaning to the right around the center 11, the roll shaft axis 9 is displaced to the right, and the rear frame 2 and the engine 15 grounded on the rear frame 2 are displaced to the right accordingly. At the same time, the rack bar 18 is displaced leftward by the rotational displacement of the roll shaft 7 with respect to the rear frame 2, and the rear wheel 6 is displaced leftward with respect to the rear frame 2 via the tie rod 14 and the knuckle arm 13. That is, the direction of the rear wheel 6 with respect to the rear frame 2 is controlled in a phase opposite to the lean direction of the front frame. As a result, the rightward displacement of the roll shaft axis 9 and the leftward displacement of the rear wheel 6 cancel each other out, and the rear wheel 6 maintains the traveling direction when the front frame was upright. The direction of the rear wheel 6 with respect to the rear frame 2 may be controlled to be in phase with the lean direction of the front frame.

FIG. 7 shows another embodiment, in which a swing arm 19 extending downward is fixed to the rear end of the roll shaft 7, and the lower end of the swing arm 19 is connected to the inner end of the tie rod 14 by a connecting rod 20. The connecting rod 20 and the tie rod 14 may be integrated and directly connected to the knuckle arm. Swing arm 1 according to the rotational displacement of roll shaft 7 due to lean of the front frame
The rear wheel 6 turns in the direction opposite to the lean side with respect to the rear frame via the 9, tie rods 14, and knuckle arms.

As described above, the front frame lean type three-wheel vehicle according to the present invention rotates the front frame supporting the steerable front wheels and the rear frame supporting the left and right rear wheels by the roll shaft in the front-rear direction and the bearing members thereof. The knuckle shaft supports the left and right rear wheels so that the left and right wheels can be pivoted to the left and right. By transmitting to the wheel, the direction of the rear wheel with respect to the rear frame is controlled in conjunction with the rotational displacement of the front frame, and the direction of the rear wheel can be displaced in the same phase as or opposite to the rotational displacement direction of the front frame. With this configuration, even if the rear frame turns sideways when the front frame leans, the orientation of the rear wheels with respect to the ground can be adjusted so as not to affect the steering characteristics. Therefore, it is possible to prevent the secondary demerit caused by such an unreasonable design without making an effort to limit the lateral phenomenon of the rear frame to a small range by specially designing the roll shaft axis direction. Increased the freedom of design of this type of front frame lean type three-wheeled vehicle,
Moreover, it has the effect of improving the steering characteristics and obtaining an extremely natural riding comfort.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a front frame lean type three-wheeled vehicle, FIG. 2 is a plan view showing an outline of the same structure, FIG. 3 is a schematic view showing a state at the same time of the front frame lean, and FIG. Is a plan view of a rear frame showing an embodiment of the present invention, FIG. 5 is a plan view showing a state at the same lean time, FIG. 6 is an enlarged vertical sectional front view of a roll shaft as viewed in the direction of arrows AA in FIG. 4, FIG. 7 is a vertical sectional front view of a roll shaft showing another embodiment. 1 ... Front frame, 2 ... Rear frame, 3 ... Handle, 4 ... Front wheel, 5 ... Seat, 6 ... Rear wheel, 7 ... Roll shaft, 8 ... Bearing member, 12 ... Knuckle shaft , 13 knuckle arm, 14 tie rod, 17 pinion, 18
...... Rack bar, 19 ...... Swing arm, 20 ...... Connecting rod.

Claims (3)

[Claims] 1. A front frame for supporting steerable front wheels,
The rear frame supporting the left and right rear wheels is rotatably pivoted by the roll shaft in the front-rear direction and its bearing member, and the left and right rear wheels are supported by the knuckle shaft so as to be pivotable left and right. By transmitting the rotational displacement of the front frame with respect to the rear frame to the rear wheel via tie rods, knuckle arms, etc., the orientation of the rear wheel with respect to the rear frame is controlled in conjunction with the rotational displacement of the front frame. A front frame lean type three-wheel vehicle characterized in that the direction of the rear wheels is displaced in the same phase as or opposite to the rotational displacement direction of the front frame. 2. A roll shaft fixed to the front frame side or a pinion fixed to a bearing member is engaged with a rack bar slidably supported on the rear frame, and the rear wheel is displaced by the horizontal sliding displacement of the rack bar. The front frame lean type three-wheel vehicle according to claim 1, characterized in that the orientation of the front frame lean type is controlled. 3. A roll wheel fixed to the front frame side or an arm on a bearing member and a link mechanism connected to the tip of the arm to control the direction of the rear wheel. Front frame lean type three-wheeled vehicle according to item.