JPH0274486A - Motorcycle - Google Patents

Abstract

PURPOSE:To improve cornering performance as well as running performance by providing a control means which energizes a front frame around a connecting shaft at its standing-up position. CONSTITUTION:A front wheel 3 is suspended from a front frame 1 after a round tire 3a has been fixed onto the frame via an inverted by front fork 2, and a rear wheel 6 which is acting as a driving wheel and is equipped with a wide flat tire 6a via a rear fork 5, is suspended from a rear frame 4. The front frame 1 and the rear frame 4 are connected rotatably with each other around a shaft 8 via a connecting shaft 8. A control means 21 energizes a rotating section 18 around the connecting shaft 8 in such a way that the front frame 1 which is rotatable around the rotating shaft 8 integrally with the rotating section 18, is forwarded to its standing-up position. This constitution makes the front frame keep standing vertically at all times at the time of running straight ahead so that straight ahead running performance can be improved. At the time of cornering, the rear wheel which is not banked, is pressed on the ground, its gripping force is thereby improved so that speedier cornering can be performed.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a motorcycle.

(Prior Art) A normal motorcycle counteracts centrifugal force by banking the vehicle body when cornering, but generally the vehicle speed must be reduced.

(Problem to be Solved) Therefore, the applicant of the present invention has proposed a motorcycle capable of high-speed cornering.

This motorcycle has a body frame that consists of a front frame that suspends the front wheel equipped with a round tire, and a rear frame that suspends the rear wheel that is the drive wheel equipped with a flat tire. They are connected via a connecting shaft, and the front frame can be banked laterally around the connecting shaft. The flat tires of the rear wheels are made wide to suppress the banking of the rear wheels and the rear frame.

When cornering such a motorcycle, the front frame is banked in the turning direction around the connecting shaft to balance centrifugal force. As mentioned above, the rear wheels are wide flat tires, so they do not bank, and therefore exhibit a large grip force, allowing a large driving force to be applied to the rear wheels, which enables high-speed cornering. It is said that

An object of the present invention is to provide a motorcycle that can further improve the running performance of a motorcycle having such excellent cornering performance.

(Means for Solving the Problems) In order to achieve the above object, the motorcycle of the present invention has the following features:
A front frame having a front wheel equipped with a round tire and a rear frame having a rear wheel as a driving wheel equipped with a wide flat tire are rotatably connected via a longitudinal connecting shaft, and the front frame is It is characterized in that a regulating means for biasing around the connecting shaft is provided in the upright position.

The present invention is characterized in that the biasing force of the regulating means when the front frame is in an upright position decreases as the vehicle speed increases.

Further, the biasing force of the regulating means increases as the amount of rotation of the front frame about the connecting shaft from the upright position increases.

Furthermore, when turning with a constant turning radius, the biasing force of the regulating means increases as the vehicle speed increases, and the rate of increase in the biasing force increases as the vehicle speed increases.

(Function) According to this means, the front frame is biased to its upright position by the regulating means, so that when traveling straight, the front frame is not only at high speeds where the gyroscopic effect of the front and rear wheels is large, but also at low speeds where the gyroscopic effect is small. The front frame is maintained in an upright state, and during cornering, the front frame is rotated around the connecting shaft and banked together with the front wheels in the turning direction, thereby balancing the centrifugal force.

At this time, since the rear wheels are wide flat tires, the rear wheels and the rear frame are always maintained in an upright state. Since the biasing force by the regulating means acts in the opposite direction to the bank of the front frame, the bank is transmitted to the rear frame and the rear wheels via the connecting shaft, and the rear wheels that are not banked are pressed against the road surface, causing the flat Strong tire grip is maintained.

When the biasing force of the regulating means in the upright position of the front frame decreases as the vehicle speed increases, the higher the speed, the smaller the biasing force of the regulating means, and the faster the cornering from a straight-ahead state. This makes it possible to bank the front frame.

Furthermore, when the biasing force of the regulating means increases with an increase in the amount of rotation of the front frame around the connecting shaft from the upright position, the bank angle of the front frame increases during cornering, and therefore the centrifugal force increases. As the biasing force increases accordingly, the force that presses the rear wheel against the road surface due to the bank of the front frame increases as the centrifugal force increases, and the grip force of the rear wheel improves.

Furthermore, when turning with a constant turning radius, the biasing force of the regulating means increases as the vehicle speed increases, and the rate of increase in the biasing force increases as the vehicle speed increases,
When cornering with a constant turning radius, the biasing force increases as centrifugal force increases, which is proportional to the square of the vehicle speed.Similarly to the above, the force that presses the rear wheels against the road increases with the increase in centrifugal force. Improves the grip of the wheel. Since the rate of increase of the centrifugal force and the biasing force increases as the vehicle speed increases, it is possible to apply a biasing force suitable for the centrifugal force.

(Example) An embodiment of the present invention will be explained in detail below using the drawings.

FIG. 1 is a side view of a first embodiment of the present invention, and FIG. 2 is an exploded perspective view of its main parts.

In FIG. 1, ■ is a front frame that suspends the front wheel 3 on which a round tire 3a is attached via an inverted front fork 2, and 4 is a drive wheel on which a wide flat tire 6a is attached via a rear fork 5. A rear frame 7 on which a certain rear wheel 6 is suspended is a seat frame. The front frame 1 and the rear frame 4 are rotatably connected around the shaft 8 via a connecting shaft 8 provided in the front-rear direction, and the rotation of the rear frame 4 is controlled by a medium-wide flat tire 6a mounted thereon. It is suppressed by the rear wheels 6. A power unit 9 such as an engine is mounted at a low position on the rear frame 4.

As shown in FIGS. 1 and 2, the front frame 1 includes a pair of side frame portions 14.14 formed in a triangular shape from an upper side member 11, a lower side member 12, and a bottom side member 13. 14 are arranged in a straight shape in plan view with the head vibrator 10 that supports the upper end of the front fork 2 being approximately the apex, and the upper side member 11 and the rear wheel of 11 are connected to the connecting member 15.
It has a connected structure.

The front frame 1 is rotated by support portions 16.16 provided on both sides of the connecting member 15 of the side frame portions 14.14 and support portions 17.17 provided at the lower end of the lower side member 12. A portion 18 is supported, and the pivot portion 18
is fitted onto a connecting shaft 8 which is fixed to the rear frame 4 via fixing means 19, 19, and is rotatably connected around the connecting shaft 8.

The rotating part 18 is connected to the 02 port 2 provided in the rear frame 4.
The regulating means 21 is controlled by the rotating part 18 so that the front frame 1, which is rotatable around the connecting shaft 8, moves toward its upright position.
is biased around the connecting shaft 8.

Further, a vehicle speed sensor 22 for detecting vehicle speed is provided at a portion of the front fork 2 where the front wheel 3 is suspended, and a gravity sensor 23 for detecting centrifugal force is provided at the rear frame 4, and the rotation of the rotating portion 18 At the same time, an angle sensor 24 is provided at the rear end of the connecting shaft 8 to detect the bank angle of the front frame 1 that is banked toward the side of the vehicle body. Each of these sensors 22
．． The output signals of 23 and 24 are input to the CPU 20.

The seat frame 7 is attached to the rear end of the front frame 1 and extends upward from the rear frame 4. The seat frame 7 includes a pair of frame portions 25 and 25 that are substantially rectangular in side view and extend in the longitudinal direction of the vehicle body, and a fuel tank 26 is provided between the frame portions 2525.
Furthermore, above it, a nigerip part 27 is attached to both frame parts 25.
．． 25, and a seat 28 and a step 29 are provided behind the knee grip portion 27.

In addition, 30 is a radiator for the engine, 31 is a front wheel steering handle, 32 is a seat cowl, and 33 is a rear wheel shock absorber.

Next, the structure of the regulating means 21 will be explained in detail with reference to FIG. FIG. 3 is a schematic cross-sectional view of the regulating means 21 taken along the line ■--■ in FIG.

This regulating means 21 supports the connecting shaft 8 in the rotating portion 18 via a Neidhardt rubber 35 made of a soft elastic material provided on the inner surface of a housing 34 having a substantially rectangular cross section. 18, it is rotatable around the connecting shaft 8. This Neidhardt rubber 35 is brought into contact with each of the four recesses of the connecting shaft 8 formed into a cross-shaped cross section in the rotating part 18, and the housing 34 rotates together with the rotating part 18 around the connecting shaft 8. Then, it is twisted and deformed elastically. At this time, the Neidhardt rubber 35 urges the rotating portion 18 toward the upright position by its restoring force.

On the other hand, the left and right side walls 34a, 34a of the housing 34
is formed into a U-shaped cross section, and the upper and lower side walls 34b, 34
It is slidable in the left and right direction along the inner surface of b.

Further, above the housing 34, an arm 36.36 which crosses in an
The arms 36 and 36 are connected to two piston rods 39 and 39, respectively, which are movable in mutually opposite directions of a hydraulic cylinder 38 controlled by the PU 20, and the lower ends of the arms 36 and 36 are connected to the slidable side wall 34a of the housing 34, respectively. .

34a.

Therefore, in the regulating means 21, the piston rod 3 is
As the arms 9 and 39 move in opposite directions, the lower ends of the arms 36 and 36 open and close, and together with this, the side walls 34a and 34a of the housing 34 move in opposite directions. In particular, when the side walls 34a, 34a are moved toward each other, the Neidhardt rubber 35 is compressed and its torsional rigidity increases.
8 is rotated around the connecting shaft 8, the force that urges them back to their original position increases.

Then, the CPU 20 controls the regulating means 21 according to the detection signals of the vehicle speed sensor 22, the gravity sensor 23, and the angle sensor 24, and controls the torsion of the Neidhardt rubber 35 according to the vehicle speed, centrifugal force, and bank angle, as described later. The above-mentioned urging force exerted on the front frame 1 by the regulating means 21 is controlled by changing the rigidity.

Next, the operation of the motorcycle of this embodiment having such a structure will be explained with reference to FIGS. 4 to 6. Figure 4 shows
A schematic front view of the motorcycle and FIGS. 5 and 6 are diagrams for explaining the characteristics of the biasing force exerted on the front frame 1 by the regulating means 21.

In this motorcycle, when traveling straight, the front frame 1, rear frame 4, etc. are upright as shown by the solid line in FIG. 4, similar to a normal motorcycle. At this time, the torsional rigidity S of the Neidhardt rubber 35 changes as shown by the solid line downward to the right in FIG. 5 with respect to the vehicle speed (2). That is, the torsional stiffness S
is large when the vehicle speed ■ is small, and decreases as the vehicle speed ■ becomes large.

Therefore, at low speeds where the gyroscopic effect of the front and rear wheels 3, 6 is small, the torsional rigidity S is large, and the force exerted by the regulating means 21 on the front frame 1 to the upright state is large, so that the front frame 1 can be easily moved by suppressing its bank. maintained in an upright position.

On the other hand, at high speeds, although the torsional rigidity S decreases and the biasing force decreases, the gyroscopic effect of the front and rear wheels 3.6 increases, so that the upright state is easily maintained as at low speeds. Since the biasing force is small, the front frame 1 can be quickly banked around the connecting shaft 8.

Next, the operation during cornering will be explained.

For example, when turning from a straight-ahead state to a corner with a cornering radius R = Ra at a specific vehicle speed V-Va, the centrifugal force G applied to the vehicle body is G = M-Va''/Ra, where the vehicle weight is M.
...... (L), and in order to counteract this centrifugal force G, the front frame 1 together with the seat frame 7 and front wheels 3 is rotated around the connecting shaft 8 in the turning direction as shown in the fourth figure. Bank it. By setting this bank angle θ to an angle corresponding to the centrifugal force G, the centrifugal force G
You can turn while maintaining balance. At this time,
Since the rear wheel 6 is equipped with a wide flat wheel 6a, the rear wheel 6 and the rear frame 4 do not bank and are maintained in an upright state.

Further, since the front frame 1 is urged to an upright position by the Neidhardt rubber 35, the bank of the front frame 1 is transmitted to the rear frame 4 and rear wheel 6 via the Neidhardt rubber 35 and the connecting shaft 8, and thereby The rear wheel 6, which does not bank, is pressed against the road surface. For this reason,
The rear wheels 6 exhibit a large grip force, and can turn by applying a large driving force to the rear wheels 6.

On the other hand, the torsional rigidity S of the Neidhardt rubber 35 increases as the bank angle e increases, as shown by a plurality of broken lines descending to the right in FIG. Each broken line shows the change in torsional stiffness S with respect to vehicle speed ■ when the bank angle θ is constant, and these show that the torsional stiffness S decreases as the vehicle speed ■ increases, similar to the case when traveling straight above. There is.

As described above, when the torsional rigidity S increases as the bank angle θ increases, the biasing force of the regulating means 21 against the front frame 1 increases as the centrifugal force G that balances the bank angle e increases. As shown in the figure, the force pressing the rear wheels 6 against the road surface increases, the grip force of the rear wheels 6 improves, and faster cornering can be performed.

In addition, since the connecting shaft 8 is disposed so as to pass above the grounding point of the front wheel 3 as shown in the first figure, the front frame l
With the banking operation, the connecting shaft 8 moves in the banking direction as shown in the fourth figure, and also points in the turning direction about the grounding point of the rear wheel 4.

Therefore, the rear wheels 4 are steered in the turning direction, improving turning performance.

The two curves sloping upward to the right in Figure 5 indicate the vehicle speeds Vl and V when entering the corner at a bank angle θ=0'' when turning from the above-mentioned straight-ahead condition to a corner with a cornering radius RaO at a specific vehicle speed Va. (V, <V2<Va), an example of a change in torsional rigidity S when the vehicle speed ■ is increased to Va while turning, and the front frame 1 is gradually banked to a bank angle θ that balances the centrifugal force G. shows.

Here, the bank angle θ that balances the centrifugal force G is set to 45°. FIG. 6 shows the change in the torsional rigidity S with respect to the bank angle θ.

In FIG. 5, since V<V2, the respective torsional stiffnesses S+ and Sz when entering a corner are 31>S2 in accordance with the characteristics of the torsional stiffness S when going straight ahead, and the vehicle speed V
a, The torsion angle 11 when the bank angle is 45° is Sa>
SI>Sz. That is, the torsional rigidity S gradually increases as the bank angle θ increases. As shown in FIG. 6, the rate of increase in torsional stiffness S as the bank angle θ increases is greater at approach vehicle speed ■2 than at approach vehicle speed ■2.

In this way, in this motorcycle, when turning with a constant cornering radius R, the rate of increase in torsional rigidity S relative to bank angle θ increases as vehicle speed 2 increases.

As can be seen from equation (1) above, the centrifugal force G is proportional to the square of the vehicle speed ■, and its rate of increase increases as the vehicle speed V increases. By increasing the rate of increase in the torsional rigidity S, the regulating means 21 applies an urging force suitable for the centrifugal force G to the front frame E.

Next, another example of the motorcycle of the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a side view of the second embodiment of the present invention, and FIG. 8 is a schematic cross-sectional view taken along the line ■--■ in FIG.

The motorcycle shown in FIG. 7 has the same basic configuration as the motorcycle shown in FIG. It is something that

As shown in FIG. 8, the regulating means 21 supports the connecting shaft 8 at the center of a housing 40 having a circular cross section, and is rotatable about the connecting shaft 8 together with the rotating portion 18. Left and right partition walls 40a and 40b of the housing 40 protrude toward the connecting shaft 8, and their tips abut against the connecting shaft 8. Further, rotary blades 41 a and 41 b are provided on the connecting shaft 8 to project upward and downward, and their tips abut against the inner surface of the housing 40 . Therefore the housing 40
The inner space is divided into four oil chambers 42a to 42d, and each oil chamber 42a to 42d is filled with oil.

Further, the upper and lower oil chambers 42a and 42d on the right side and the upper and lower oil chambers 42a and 42d on the left side are respectively partitioned by a partition wall 41a,
The oil chambers 42a and 42d are connected by orifices 43a and 43b provided in the motor 44.
It is connected by a bypass 46 via a pulp 45 which is opened and closed by a. Then, the motor 44 is
Controlled by PU 20.

In the regulating means 21 configured in this way, for example, when the housing 40 rotates clockwise around the connecting shaft 8,
The oil pressure in the oil chamber 42d on the lower right side increases, and oil flows out into the oil chamber 42a through the orifice 43a and the bypass 46. At this time, for example, when the pulp 45 is closed, oil cannot flow through the bypass 46 and the housing 40
rotation is suppressed.

Therefore, in a motorcycle equipped with this regulating means 21, the CPII 20 controls the force exerted by the regulating means 21 on the front frame 1 to the upright position by controlling the opening/closing degree of the pulp 45. There is. By controlling this biasing force according to the same characteristics as in the first embodiment, the same operation as in the first embodiment is obtained.

In the second embodiment, the swinging portion 18 may of course be provided with the Neidhardt rubber 35.

(Effects) As is clear from the above description, according to the motorcycle of the present invention, by providing the regulating means for biasing the front frame to the upright position around the connecting shaft, the front frame is always maintained when traveling straight. It is maintained upright, improving straight-line driving performance, and when cornering, the non-banked rear wheels are pressed against the road surface, improving their grip and enabling high-speed cornering.

By reducing the biasing force applied to the front frame by the regulating means as the vehicle speed increases, the biasing force becomes smaller as the vehicle speed increases, and the front frame can be quickly banked during high-speed cornering. .

Furthermore, by increasing the biasing force applied to the front frame by the regulating means as the bank angle of the front frame increases, the grip force of the rear wheels increases during cornering as the centrifugal force that balances with the bank angle increases. Improved and faster cornering.

Furthermore, by increasing the rate of increase of the biasing force as the vehicle speed increases, it is possible to apply a biasing force suitable for the centrifugal force to the front frame during cornering, thereby reliably improving the grip force of the rear wheels. , it is possible to provide a motorcycle with excellent cornering performance.

[Brief Description of the Drawings] Fig. 1 is a side view of the first embodiment of the motorcycle of the present invention, Fig. 2 is an exploded perspective view of the main parts of Fig. 1, and Fig. 3 is a side view of the first embodiment of the motorcycle of the present invention.
4 is a schematic front view for explaining the operation of the first embodiment, FIGS. 5 and 6 are line diagrams for explaining the characteristics of the biasing force of the regulating means 21, FIG. 7 is a side view of the second embodiment of the present invention, and FIG. 8 is a sectional view taken along the line ■--■ in FIG. 1...Front frame 3...Front wheel 3a...Round tire 4...Main frame 6...Rear wheel 6a...Flat tire 8...Connection shaft 21...Regulating means knee 71 death Prayer torsional rigidity S vl Vehicle speed ■ FIG, 6 Torsional rigidity S υ for t4 Kohanoso

Claims (1)

[Scope of Claims] 1. A front frame including a front wheel equipped with a round tire and a rear frame including a rear wheel, which is a driving wheel equipped with a wide flat tire, can be freely rotated via a longitudinal connecting shaft. 1. A two-wheeled motor vehicle, characterized in that a regulating means is provided for connecting the front frame to the upright position and biasing the front frame around the connecting shaft. 2. The motorcycle according to claim 1, wherein the biasing force of the regulating means when the front frame is in an upright position decreases as the vehicle speed increases. 3. The motorcycle according to claim 1, wherein the biasing force of the regulating means increases as the amount of rotation of the front frame about the connecting shaft from an upright position increases. 4. Claim 1, wherein when turning with a constant turning radius, the biasing force of the regulating means increases as the vehicle speed increases, and the rate of increase of the biasing force increases as the vehicle speed increases. Motorcycles listed.